Magazine assembly for fastening tool

Information

  • Patent Grant
  • 6679413
  • Patent Number
    6,679,413
  • Date Filed
    Monday, April 29, 2002
    22 years ago
  • Date Issued
    Tuesday, January 20, 2004
    20 years ago
Abstract
A magazine assembly for a fastening tool. The magazine assembly includes a feed mechanism having a fastener follower that includes a cam device. The feed mechanism also includes a cam follower which is employed to engage the cam device so that fasteners may be loaded into the magazine assembly. The cam follower alternately engages and disengages the cam device in response to movement of the fastener follower relative to the cam device. The magazine assembly also includes a clamp assembly for coupling the magazine assembly to the body of a fastening tool.
Description




FIELD OF THE INVENTION




The present invention generally relates to a fastening tool for dispensing fasteners from a magazine assembly into a workpiece and more specifically to an improved magazine assembly for a fastening tool.




BACKGROUND OF THE INVENTION




A number of pneumatically operated devices have been developed for use in driving fasteners, such as staples and nails, into workpieces. These tools typically employ a magazine assembly for holding a plurality of the fasteners and feeding the fasteners into the nose of the tool prior to the installation of the fasteners into a workpiece.




Despite the wide spread use of such tools, several drawbacks have been noted. One such drawback concerns the use of a secondary lever to release the position of a nail pusher or follower structure from a lowered and locked condition after the loading of fasteners into the magazine assembly. Such mechanisms are often times cumbersome to operate and tend to increase the weight and overall cost of the magazine assembly.




SUMMARY OF THE INVENTION




In one preferred form, the present invention provides a magazine assembly for holding and progressively dispensing a plurality of fasteners. The magazine assembly includes a magazine housing and a feed mechanism for feeding the fasteners through a hollow cavity in the magazine housing toward a dispensing end of the magazine housing. The feed mechanism includes a fastener follower, which is configured to support the fasteners in the magazine housing, and which includes a cam device. The feed mechanism also includes a cam follower that is coupled to the magazine housing at an end opposite the dispensing end. The cam follower alternately engages the cam device, such that the fastener follower is restrained from movement toward the dispensing end of the magazine housing, and disengages the cam device. Disengagement of the cam follower from the cam device occurs solely from downward motion of the fastener follower relative to the cam follower beyond a predetermined disengaging point.




In another preferred form, the present invention provides a clamp mechanism for removably coupling a magazine assembly to a tool without resort to the use of tools.




Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.











BRIEF DESCRIPTION OF THE DRAWINGS




Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:





FIG. 1

is a left side view of a tool constructed in accordance with the teachings of a preferred embodiment of the present invention;





FIG. 2

is a right side view of the tool of

FIG. 1

;





FIG. 3

is an exploded perspective view of the tool of

FIG. 1

;





FIG. 4

is a sectional view of the tool of

FIG. 1

taken through its longitudinal axis;





FIG. 4



a


is a section view taken along the line


4




a





4




a


of

FIG. 4

;





FIG. 5

is a top view of the tool of

FIG. 1

;





FIG. 6

is a sectional view taken along the line


6





6


of

FIG. 5

;





FIG. 7

is an enlarged portion of

FIG. 4

illustrating the nose assembly in greater detail;





FIG. 8

is a front view of a portion of the tool of

FIG. 1

illustrating the nose body and the contact tip in greater detail;





FIG. 9

is a sectional view taken along the line


9





9


of

FIG. 2

;





FIG. 9



a


is sectional view of a portion of the magazine clamp assembly illustrating the spring collar in greater detail;





FIG. 9



b


is a perspective view of a portion of the magazine clamp assembly illustrating the clamp pin in greater detail;





FIG. 10

is an enlarged portion of

FIG. 4

illustrating the trigger assembly in greater detail;





FIG. 11

is an exploded view of the tool of

FIG. 1

;





FIG. 12

is an enlarged portion of

FIG. 4

illustrating the rear of tool in greater detail;





FIG. 13

is a sectional view of a portion of the exhaust manifold illustrating the construction of the exhaust ports in greater detail;





FIG. 14

is an enlarged portion of

FIG. 4

illustrating the engine assembly in greater detail;





FIG. 15

is an enlarged portion of

FIG. 11

illustrating the engine assembly in greater detail;





FIG. 16

is a sectional view of the sleeve taken along its longitudinal axis;





FIG. 17

is a sectional view taken along the line


17





17


of

FIG. 16

;





FIG. 18

is a sectional view similar to that of

FIG. 10

but illustrating the trigger assembly in an actuated condition;





FIG. 19

is an exploded perspective view of the magazine assembly;





FIG. 20

is a sectional view taken along the line


20





20


of FIG.


1


and illustrating the construction of the magazine body assembly;





FIG. 21

is a rear view of a portion of the magazine body assembly;





FIG. 22

is a side view of a portion of the magazine body assembly illustrating the L-shaped pin aperture in greater detail;





FIG. 23

is a top view of a guide structure;





FIG. 24

is a front view of the bracket structure;





FIG. 25

is a rear view of a portion of the bracket structure;





FIG. 26

is a side view of a portion of the bracket structure;





FIG. 27

is a side view of the follower structure;





FIG. 28

is a top view of a portion of the follower structure illustrating the construction of a portion of the follower body, the follower guide and the actuating lever;





FIG. 29

is a view of a portion of the follower structure illustrating the configuration of the forward leg of the follower body;





FIG. 30

is a view of a portion of the follower structure illustrating the configuration of the rearward leg of the follower body;





FIG. 31

is a front view of a portion of the follower structure;





FIG. 32

is a partial view of the follower structure from a side opposite the side which is illustrated in

FIG. 27

;





FIG. 32



a


is a view similar to that of

FIG. 32

but illustrating the leg of the cam follower engaged into the catch portion of the second loading cam;





FIG. 33

is a side view of the follower spring;





FIG. 34

is a side view of the magazine end cap assembly;





FIG. 35

is a sectional view of a portion of the end cap structure taken along the line


35





35


in

FIG. 34

;





FIG. 36

is a sectional view of a portion of the end cap structure taken along the line


36





36


in

FIG. 35

;





FIG. 37

is a top view of a portion of the end cap structure;





FIG. 38

is a front view of the cam follower;





FIG. 39

is a partial side view of the cam follower;





FIG. 40

is an enlarged portion of the cam follower illustrated in

FIG. 38

;





FIG. 41

is a partial side view of the cam follower illustrating the follower hook in greater detail;





FIG. 42

is a partial section view illustrating the position of the cam follower on the pivot structure just prior to contact between the loading cam and the follower hook;





FIG. 43

is a partial section view similar to that of

FIG. 42

but illustrating the cam follower when the follower hook is contacting the first loading cam portion;





FIG. 44

is a side view of the follower structure engaged to the magazine end cap assembly;





FIG. 45

is a section view taken along the line


45





45


illustrating the follower hook disposed within the capture aperture;





FIG. 46

is a side view of a portion of a tool constructed in accordance with the teachings of the an alternate embodiment of the present invention illustrating the magazine assembly removed from the tool;





FIG. 47

is a side view similar to that of

FIG. 46

but illustrating the magazine assembly coupled to the tool;





FIG. 48

is a perspective view similar to that of

FIG. 9



b


but illustrating an alternately constructed clamp pin; and





FIG. 49

is a partial front view similar to that of

FIG. 24

but illustrating a bracket structure having an alternately constructed slotted pin aperture.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




With reference to

FIG. 1

of the drawings, a fastening tool constructed in accordance with the teachings of the present invention is generally indicated by reference numeral


10


. Fastening tool


10


is illustrated to include a detachable magazine assembly


20


and a fastening tool portion


30


. The fastening tool portion


30


includes a nose assembly


40


, a housing assembly


42


, a cap assembly


44


, an engine assembly


46


and a trigger assembly


48


.




Nose Assembly




With reference to

FIGS. 1 through 9

, the nose assembly


40


is illustrated to include a nose structure


50


, a contact trip


52


, a trigger lever


54


and a contact trip-return spring


56


. The nose structure


50


includes a nose body


60


, a pair of magazine stabilizing tabs


62


, a magazine flange


64


, a pair of magazine guide posts


66


, a mounting base


68


, a spring post


70


and a pair of contact trip guides


72


. The nose body


60


is generally U-shaped, with the legs


80


of the “U” being inwardly offset to form a semi-circular blade cavity


82


. The inwardly offset legs


80


of the nose body


60


also serve as a guide surface


84


for guiding the lower front portion


86


of the contact trip


52


. The contact trip guides


72


are coupled to the top of the nose body


60


and form a guide surface for guiding the portion


88


of the contact trip


52


that extends over the nose body


60


.




The magazine stabilizing tabs


62


are situated on opposite sides of the nose body


60


and are spaced apart by a predetermined distance. The magazine flange


64


is a generally flat structure that is coupled to the bottom of the nose body


60


and that includes a lock-out dog aperture


90


. The magazine guide posts


66


, which are cylindrically shaped in the particular embodiment illustrated, extend downwardly and rearwardly from the magazine flange


64


. The magazine stabilizing tabs


62


, magazine flange


64


and magazine guide posts


66


are discussed in greater detail, below.




The mounting base


68


is coupled to the magazine flange


64


and the nose body


60


and includes a pair of mounting apertures


94


, a nose seal groove


96


and a nose guide


98


. The nose guide


98


is generally cylindrically shaped and includes an internal cavity


100


that having a cross-section that is configured to receive the fastener F and which may include a fastener stop


102


which is configured to prevent the fasteners F from traveling rearwardly toward the engine assembly


46


. In the embodiment illustrated, the internal cavity


100


is generally semi-circular in shape but which includes a key-shaped fastener stop


102


. The nose seal groove


96


is formed around the outer perimeter of the nose guide


98


and is sized to receive a nose seal


104


, which is an O-ring seal in the particular embodiment illustrated. The spring post


70


is coupled to the top of the mounting base


68


and includes a boss


108


that is sized to fit within the contact trip-return spring


56


.




The contact trip


52


is fit over and slides on the nose body


60


, being guided thereon by the inwardly offset legs


80


of the nose body


60


and the contact trip guides


72


. Preferably, the effective length of the contact trip


52


is adjustable so as to permit the tool operator to vary the depth at which the tool


10


sets the fasteners F. A spring protrusion


110


, which is sized to engage the inside diameter of the contact trip-return spring


56


, is formed in the rear of the contact trip


52


. The contact trip-return spring


56


is set over the boss


108


on the spring post


70


and the spring protrusion


110


on the contact trip


52


and exerts a spring force that biases the contact trip


52


away from the spring post


70


. Forward motion of the contact trip


52


is checked by a contract trip stop


114


that is formed onto a side of the nose body


60


and which contacts the contact trip


52


at a predetermined point.




The trigger lever


54


is fixedly coupled to the contact trip


52


at a first end


120


and extends rearwardly from the nose structure


50


where a second end


122


engages the trigger assembly


48


in a conventional manner that is well known in the art. Briefly, the trigger assembly


48


includes a primary trigger


126


, a secondary trigger


128


and a trigger valve


130


that selectively controls the flow of compressed air to the engine assembly


46


. The primary trigger


126


is pivotably mounted to the housing assembly


42


and movable in response to the tool operator's finger. Movement of the primary trigger


126


will not, in and of itself, alter the state of the trigger valve


130


. Rather, the second end


122


of the trigger lever


54


must also move rearwardly and into contact with the secondary trigger


128


before the state of the trigger valve


130


is changed to permit compressed air to flow to the engine assembly


46


. A stop member


134


, which is configured to interact with the magazine assembly


20


in a matter that will be discussed in greater detail below, is coupled to the trigger lever


54


below the magazine flange


64


and extends inwardly toward the nose body


60


. In the particular embodiment illustrated, the stop member


134


is die-punched into the trigger lever


54


and is offset inwardly therefrom toward the nose body


60


.




Housing Assembly




Housing assembly


42


includes a unitarily formed housing


150


, a piston bumper


152


, a magazine clamp assembly


154


and a housing seal


156


, which is illustrated to be an O-ring seal in the example provided. The housing


150


includes a housing body


160


, a trigger housing


162


, a nose housing


164


and a handle portion


166


. The housing body


160


is a container-like structure having a front base


170


and an outwardly tapering sidewall


172


that cooperate to form a housing cavity


174


. The outwardly tapering sidewall


172


terminates at the rear of the housing body


160


at a rear housing face


176


, which in the particular embodiment illustrated, includes a housing seal groove


178


that is configured to receive the housing seal


156


. A guide bore


180


is formed into the inside face


182


of the housing cavity


174


and terminates at its forward end at a guide stop


184


. A nose guide aperture


188


is formed through the front base


170


of the housing body


160


.




The nose housing


164


is coupled to the front base


170


of the housing body


160


and extends forwardly therefrom. The nose housing


164


includes an upper shroud


200


, a pair of sidewalls


202


and a pair of spaced apart bosses


204


, each of which having a threaded aperture


206


. The upper shroud


200


, sidewalls


202


and spaced apart bosses


204


cooperate to locate the nose assembly


40


to the housing


150


and the nose guide


98


is inserted into the nose guide aperture


188


. Threaded fasteners


210


are placed through each of the mounting apertures


94


in the mounting base


68


and threadably engaged to the threaded apertures


206


in the spaced apart bosses


204


to fixedly but removably couple the nose assembly


40


to the housing


150


. The axis


212


of the threaded fasteners


210


is skewed toward the rear of the tool


10


, causing the threaded fasteners


210


to exert a clamping force that pushes the nose assembly


40


downwardly onto the spaced apart bosses


204


and rearwardly against the front face of the front base


170


to thereby compress the nose seal


104


and sealingly engage the nose structure


50


to the housing body


160


. The upper shroud covers the spring post


70


, the contact trip-return spring


56


and a portion of the rear of the contact trip


52


to prevent foreign objects from lodging between the rear of the contact trip


52


and the spring post


70


.




The handle portion


166


is preferably non-circular in shape and contoured to comfortably fit the hand of a tool operator. The distal end


250


of the handle portion


166


is enlarged so as to render the handle portion


166


less prone to slipping out of the tool operator's hand. With additional reference to

FIG. 4



a


, a clamp boss


252


is coupled to the forward face of the distal end


250


of the handle portion


166


. The clamp boss


252


includes a clamp boss base


254


that extends toward the front of the tool


10


, a clamp boss sidewall


256


that wraps around the perimeter of the clamp boss base


254


and an annular intermediate clamp boss wall


258


that cooperates with a portion of the clamp boss sidewall


256


to form a circular spring cavity


260


. The clamp boss base


254


and the clamp boss sidewall


256


cooperate to form a clamp cavity


262


into which the magazine clamp assembly


154


is disposed. A pair of U-shaped pin apertures


264


, which will be discussed in further detail below, are formed into an end of the clamp boss sidewall


256


.




The handle portion


166


intersects both the housing body


160


and the trigger housing


162


and includes an air inlet cavity


270


which extends through the distal end


250


of the handle portion


166


to receive a supply of compressed air. The air inlet cavity


270


extends through the handle portion


166


and into both the housing cavity


174


and the trigger housing


162


to permit the compressed air to be directed through the tool


10


in a predetermined manner that will be described in detail, below.




In the example provided, the magazine clamp assembly


154


is illustrated to include a clamp pin


300


, a compression spring


302


, a spring collar


304


, an actuating cam


306


and a coupling pin


308


. The clamp pin


300


includes a head portion


322


, a first body section


324


, which is coupled to the head portion


322


, and a second body section


326


that is coupled to the opposite end of the first body section


324


. The first body section


324


is generally cylindrically shaped and includes a pair of parallel flats


328


. The second body section


326


is generally cylindrically shaped but has an outer diameter that is smaller than that of the first body section


324


. The head portion


322


includes a frusto-conical abutting face


330


.




The spring collar


304


includes a first annular portion


340


having a diameter that is sized to fit within the compression spring


302


, and a second annular portion


342


that is relatively larger in diameter than the compression spring


302


and which has a flat contact surface


344


. A pin aperture


346


is formed through the spring collar


304


that is sized to receive the second body section


326


of the clamp pin


300


.




The actuating cam


306


has a base portion


350


and a leg portion


352


which are arranged relative to one another in an L-shape. The end of the base portion


350


opposite the intersection point


354


between the base and leg portions


350


and


352


includes a coupling pin aperture (not specifically shown) which is sized to engage the coupling pin


308


. The leg portion


352


of the actuating cam


306


is arcuate in shape and includes a plurality of gripping protrusions


356


or is otherwise textured on its inside surface so as to improve the tool operator's ability to move the actuating cam


306


in a desired direction. A slot


358


, which is sized to engage the second body segment


326


of the clamp pin


300


in a slip-fit manner, is formed into the actuating cam


306


through the base portion


350


and a portion of the leg portion


352


.




The clamp pin


300


extends through a pin aperture


360


formed into the clamp boss base


254


of the clamp boss


252


such that the second body section


326


extends into the spring cavity


260


. The compression spring


302


is positioned over the second body section


326


and into the spring cavity


260


. The spring collar


304


is placed over the second body section


326


such that the first annular portion


340


is disposed inside the compression spring


302


. The base portion


350


of the actuating cam


306


is positioned into contact with the flat contact surface


344


such that the second body segment


326


extends into the portion of the slot


358


that is formed into the base portion


350


of the actuating cam


306


. The coupling pin


308


, which is a roll-pin in the example illustrated, is positioned into one of the U-shaped pin apertures


264


and driven through the base portion


350


of the actuating cam


306


and into engagement with a pin aperture


364


in the second body segment


326


of the clamp pin


300


. Accordingly, the coupling pin


308


pivotably couples the actuating cam


306


to the clamp pin


300


. Rotation of the actuating cam


306


about the coupling pin


308


places the intersection point


354


into contact with the flat contact surface


344


, causing the spring collar


304


to compress the compression spring


302


and transmit a clamping force to the head portion


322


of the clamp pin


300


. When the actuating cam


306


has been pivoted sufficiently so as to place the leg portion


352


into contact with the flat contact surface


344


, the force exerted by the compression spring


302


urges the spring collar


304


against the leg portion


352


to releasably lock the actuating cam


306


in place. The clamp cavity


262


protects the actuating cam


306


from being contacted during the operation of the tool


10


, thereby guarding against the inadvertent unlocking or releasing of the actuating cam


306


.




In

FIG. 10

, the trigger housing


162


is configured to receive the trigger assembly


48


and includes a supply port


370


, which is coupled to the air inlet cavity


270


to provide the trigger assembly


48


with a source of compressed air. A biasing port


372


extends from the trigger housing


162


through the guide bore


180


in the housing cavity


174


that permits the trigger assembly


48


to direct air to or exhaust air from the housing cavity


174


.




As shown in

FIGS. 7 and 11

, the piston bumper


152


is a unitarily formed molded elastomeric structure. In the particular example illustrated, the piston bumper


152


has a cylindrical body portion


390


and an annular lip


392


. The cylindrical body portion


390


preferably includes a first annular bumper portion


396


and a second annular bumper portion


398


that is generally larger in diameter than the first annular bumper portion


396


and which is disposed between the first annular bumper portion


396


and the annular lip


392


. The annular lip


392


extends radially outwardly of the body portion


390


and includes a front abutting face


400


that is configured to abut the inside surface


402


of the housing body


160


and sealingly engage the front base


170


of the housing body


160


. The annular lip


392


also includes a rear abutting face


404


having a first annular lip portion


406


and a second annular lip portion


408


that that lies radially outwardly of and recessed forwardly relative to the first annular lip portion


406


. The rear abutting face


404


and a cylindrically-shaped driver blade aperture


410


that extends through the center of the piston bumper


152


will be described in detail, below.




Cap Assembly




With reference to

FIGS. 11 and 12

, the cap assembly


44


includes a cap housing


420


, an exhaust manifold


422


and a top bumper


424


. The cap housing


420


includes an outer cap wall


430


that is generally flat at the rear of the tool


10


, but folds over on its sides to form a cup-like container having a generally flat forward face


432


that is configured to engage the housing seal


156


to permit the cap housing


420


to be sealingly coupled to the rear of the housing


150


.




The cap housing


420


also includes a plurality of foot tabs


434


, a plurality of strengthening gussets (not specifically shown), an annular exhaust port wall


438


, an exhaust button


440


and a cylindrical locating hub


442


having a threaded aperture


444


formed therethrough. The foot tabs


434


extend forwardly from the flat portion of the outer cap wall


430


beyond the front face


432


by a predetermined distance. The outside diameter of the foot tabs


434


is sized such that the foot tabs


434


fit within the housing cavity


174


. The foot tabs


434


will be discussed in greater detail, below. The strengthening gussets are employed to couple both the foot tabs


434


or the outer cap wall


430


to the annular exhaust port wall


438


, which extends forwardly from the flat rear portion


446


of the outer cap wall


430


. The exhaust button


440


is an annular member that also extends forwardly from the flat rear portion


446


of the outer cap wall


430


but which is spaced apart from the annular exhaust port wall


438


and the locating hub


442


. A plurality of primary exhaust ports


450


are formed through the exhaust button


440


and a plurality of secondary exhaust ports


452


are formed through the portion of the outer cap wall


430


between the annular exhaust port wall


438


and the exhaust button


440


.




The exhaust manifold


422


is preferably unitarily formed from a molded from a plastic material and includes a center hub


460


, an annular spacing wall


462


and an annular manifold wall


464


. The center hub


460


is configured to fit between the exhaust button


440


and the locating hub


442


and includes a hub aperture


468


that is configured to engage the locating hub


442


in a slip fit manner. The annular spacing wall


462


is coupled to the forward-most portion of the center hub


460


and is spaced apart from the exhaust button


440


. The annular manifold wall


464


is coupled to the outer perimeter of the annular spacing wall


462


and includes a plurality of circumferentially extending exhaust slots


470


that are spaced around the circumference of the annular manifold wall


464


. The exhaust slots


470


are generally U-shaped and as best shown in

FIG. 13

, have a rear edge


472


that tapers rearwardly and inwardly toward the center hub


460


.




Returning to

FIGS. 11 and 12

, the top bumper


424


preferably includes a dampening member


480


that is molded from an elastomeric material, such as urethane, and a structural member


482


, such as a washer, that is molded into the dampening member


480


. The dampening member


480


is a cup-shaped structure that is sized to fit within the center hub


460


of the exhaust manifold


422


. The dampening member


480


includes an annular wall


484


that extends forwardly from the base


486


of the dampening member


480


. A ridge


488


is formed into the forward end of the annular wall


484


, thereby creating a groove


490


between the base


486


of the dampening member


480


and the ridge


488


. A plurality of slits


492


are formed into the annular wall


484


, creating a plurality of wall segments


494


that are flexibly coupled to the base


486


. A threaded fastener


496


is threadably engaged to the threaded aperture


444


in the locating hub


442


to fixedly but removably couple the top bumper


424


to the cap housing


420


. The structural member


482


is employed so as to permit the clamping force that is exerted by the threaded fastener


496


to be transmitted through the top bumper


424


without crushing the base


486


of the dampening member


480


. A portion of the clamping force is transmitted through the base


486


of the dampening member


480


and into the center hub


460


of the exhaust manifold


422


to maintain the exhaust manifold


422


in a stationary position relative to the cap housing


420


.




Engine Assembly




Engine assembly


46


is shown to include a cylinder assembly


500


, a piston assembly


502


, a rod or driver blade


504


. The cylinder assembly


500


includes a hollow, cylindrical, and unitarily constructed sleeve


510


, an inner exhaust port seal


512


, an outer exhaust port seal


514


, a cap flange seal


516


, rear and front guide seals


518


and


520


, a guide assembly


522


, a compensating valve


524


, a rear spring flange


526


, a spring


528


, a front spring flange


530


and a front spring flange seal


532


. In the particular embodiment illustrated, inner exhaust port seal


512


, outer exhaust port seal


514


, rear and front guide seals


518


and


520


and front spring flange seal


532


are conventional, commercially available O-ring seals. The cap flange seal


516


is a molded elastomeric seal having an outside surface with a generally flat seal face


540


and first and second radially inwardly extending flanges


542


and


544


, respectively, that are spaced apart from one another to form an engagement groove


546


therebetween.




With additional reference to

FIG. 16

, the sleeve


510


is shown to include a first sleeve body portion


550


, an annular sleeve flange


552


, a second sleeve body portion


554


having a maximum outer diameter that is generally the same as that of the first sleeve body portion


550


and a third sleeve body portion


556


having a maximum outer diameter that is generally larger than that of the first sleeve body portion


550


. The first sleeve body portion


550


includes a first U-shaped seal groove


560


, which is sized to receive the front spring flange seal


532


, a plurality of circumferentially-spaced front exhausting ports


562


, a spring flange groove


564


, which is sized to receive the rear spring flange


526


, a valve groove


566


, which is discussed in greater detail, below, and a second U-shaped seal groove


568


, which is sized to receive the front guide seal


520


.




The valve groove


566


has a first U-shaped portion


570


, a second U-shaped portion


572


and a plurality of valve apertures


574


. The first U-shaped portion


570


is sized to receive the compensating valve


524


, which in the particular embodiment illustrated, is a flat elastomeric band


580


. The second U-shaped portion


572


is disposed within the first U-shaped portion


570


, but has a diameter that is somewhat smaller than that of the first U-shaped portion


570


so as to define an annular ring that extends around the circumference of the first U-shaped portion


570


. In the particular embodiment illustrated, the diameter of the second U-shaped portion


572


is about 0.010 inches to about 0.030 inches smaller in diameter than the first U-shaped portion


570


. The valve apertures


574


are illustrated to be relatively small diameter holes that are located within the second U-shaped portion


572


and which are drilled through the sleeve


510


. The valve apertures


574


will be discussed in greater detail, below, as will the set of front exhausting ports


562


that are located between the first U-shaped seal groove


560


and the spring flange groove


564


.




The annular sleeve flange


552


extends radially outwardly from the first sleeve body portion


550


of the sleeve


510


and separates the first and second sleeve body portions


550


and


554


from one another. A third U-shaped seal groove


584


, which is sized to receive the rear guide seal


518


is formed into the outer surface of the annular sleeve flange


552


.




The majority of the second sleeve body portion


554


of the sleeve


510


is of approximately the same outer diameter as the first sleeve body portion


550


. The rear end of the second sleeve body portion


554


, however, includes a flange portion


590


that extends radially outwardly to form a seal lip


592


and a fourth U-shaped seal groove


594


prior to its connection with the third sleeve body portion


556


. The seal lip


592


is configured to engage the engagement groove


546


formed into the cap flange seal


516


and abut the first and second radially inwardly extending flanges


542


and


544


. The fourth U-shaped seal groove


594


is configured to receive a portion of the first radially inwardly extending flange


542


.




The third sleeve body portion


556


is fixedly coupled to the end of the second sleeve body portion


554


and is larger in diameter than the outer diameter of the first sleeve body portion


550


. A fifth U-shaped seal groove


600


is formed into the outer surface of the third sleeve body portion


556


and is sized to receive the outer exhaust port seal


514


. A plurality of circumferentially extending rear exhaust slots


604


are disposed around the perimeter of the third sleeve body portion


556


. The rear exhaust slots


604


are located between the fourth and fifth U-shaped seal grooves


594


and


600


. A sixth U-shaped seal groove


608


, which is configured to receive the inner exhaust port seal


512


, is formed into the inner diameter of the third sleeve body portion


556


.




The hollow cavity


610


that is formed through the sleeve


510


has a first cavity portion


612


that is generally of a constant diameter over the portion of its length that includes the first and second sleeve body portions


550


and


554


and the annular sleeve flange


552


. The hollow cavity


610


also has a second cavity portion


614


having a larger diameter than that of the first cavity portion


612


.




In

FIG. 14

, the guide assembly


522


is shown to include a guide


650


and first and second housing seals


652


and


654


, which in the particular embodiment illustrated, are O-ring seals. The guide


650


is a molded plastic component, having a stepped-diameter body portion


660


, a plurality of longitudinally extending legs


662


, a locating tab


664


and a plurality of stop tabs


668


. The stepped-diameter body portion


660


includes a flange bore


670


, which is sized to receive the annular sleeve flange


552


and sealingly engage the rear guide seal


518


, a body bore


672


, which is sized to receive the first sleeve body portion


550


and sealingly engage the front guide seal


520


, and an abutting flange


676


that forms the transition between the flange bore


670


and the body bore


672


.




The longitudinally extending legs


662


extend away from the stepped-diameter body portion


660


and are spaced apart circumferentially in equal amounts. The locating tab


664


is positioned on the same side of the stepped-diameter body portion


660


as the longitudinally extending legs


662


between two of the longitudinally extending legs


662


. The locating tab


664


is employed to signify the presence of an air gallery


680


and locate the guide assembly


522


relative to the housing assembly


42


. The air gallery


680


is configured to permit air to flow through the stepped-diameter body portion


660


from a point between the first and second housing seals


652


and


654


through the stepped-diameter body portion


660


and out the abutting flange


676


.




The rear and front guide seals


518


and


520


and the elastomeric band


580


that forms a portion of the compensating valve


524


are initially installed to the sleeve


510


. Thereafter, the guide assembly


522


is positioned over the first sleeve body portion


550


and pushed onto the sleeve


510


such that the flange bore


670


and body bore


672


are sealingly engaged to the rear and front guide seals


518


and


520


, respectively, and the abutting flange


676


abuts the annular sleeve flange


552


.




The rear spring flange


526


is next installed to the sleeve


510


. The rear spring flange


526


is a plastic collar that is split on one side to permit the ends of the rear spring flange


526


to be spread apart so that it may be loaded onto the first sleeve body portion


550


of the sleeve


510


and into the spring flange groove


564


. The rear spring flange


526


has a cylindrically shaped body portion


690


and a flange portion


692


that extends radially-outwardly from the body portion


590


in a manner that provides the rear spring flange


526


with a L-shaped cross-section. The rear spring flange


526


is located to the spring flange groove


564


such that the flange portion


692


is nearest the annular sleeve flange


552


.




The front spring flange


530


is a plastic collar having a tapering outside diameter


596


and a generally flat rear face


698


. The inside surface


700


of the front spring flange


530


is generally cylindrical, but includes an annular protrusion


702


that extends radially inwardly of the remainder of the inside surface


700


and which engages the first sleeve body portion


550


of the sleeve


510


in a slip-fit manner.




The spring


528


is a conventional compression spring having both ends ground flat. The spring


528


is disposed over the first sleeve body portion


550


of the sleeve


510


such that its rear end abuts the flange portion


692


of the rear spring flange


526


. Thereafter, the front spring flange


530


is positioned such that its rear face


698


contacts the second end of the spring


528


. The front spring flange


530


is pushed toward the annular sleeve flange


552


to compress the spring


528


a sufficient distance to permit the front spring flange seal


532


to be inserted into the first U-shaped seal groove


560


. Thereafter, the front spring flange


530


is moved toward the front of the sleeve


510


such that the front spring flange seal


532


is sealingly engaged with the inside surface


700


of the front spring flange


530


. The rear side of the front spring flange seal


532


contacts the annular protrusion


702


to limit the forward travel of the front spring flange


530


prior to the installation of the engine assembly


46


to the housing assembly


42


. Forward motion of the guide assembly


522


along the sleeve


510


is checked by contact between the stop tabs


668


and the rear surface of the flange portion


692


of the rear spring flange


526


to thereby prevent the guide


650


from becoming disengaged from the rear and front guide seals


518


and


520


. Construction in this manner is highly advantageous in that it permits the entire cylinder assembly


500


to be pre-assembled outside of the housing assembly


42


in a relatively easy and cost efficient manner.




The piston assembly


502


includes a piston


720


and a ring


722


. In the example provided, the piston


720


is shown to include a first piston portion


730


and a second piston portion


732


. The first piston portion


730


in an annular member that is smaller in diameter than the first cavity portion


612


of the hollow cavity


610


in the sleeve


510


. A U-shaped annular ring groove


734


is formed around the circumference of the first piston portion


730


that is sized to receive the ring


722


. In the embodiment illustrated, the ring


722


is shown to be fabricated from a plastic material and have a rectangular cross-section. The ring


722


is split to permit its ends of the ring


722


to be spread apart so that it may be loaded around the first piston portion


730


and into the ring groove


734


. The second piston portion


732


is an annular member that is smaller in diameter than the first piston portion


730


. The second piston portion


732


is coupled to the rear end of the first piston portion


730


and includes a pair of wrench flats


740


and a locking protrusion


744


, both of which will be discussed in more detail, below. A generous fillet radius


746


is employed at the intersection between the first and second piston portions


730


and


732


so as to reduce the concentration of stress within the piston


720


.




The construction of the driver blade


504


is largely conventional and as such, a detailed discussion of it is neither required nor within the scope of this disclosure. Briefly, the driver blade


504


is shown to include a coupling portion


760


and a driver body


762


. In the example provided, the coupling portion


760


includes a collar


764


and a threaded portion


766


which are formed into the rear end of the driver blade


504


. The wrench flats


740


on the second piston portion


732


are employed to facilitate relative rotation between the driver blade


504


and the piston


720


to permit the threaded portion


766


to threadably engage a threaded aperture


768


that is formed through the piston


720


and to permit the collar


764


to engage the front surface


770


of the piston


720


to generate a clamping force that fixedly but removably couples the piston


720


and the driver blade


504


together. Coupling of the piston


720


and the driver blade


504


via a threaded connection is presently preferred so as to permit the servicing and replacement of the driver blade


504


, since this portion of the tool


10


is essentially perishable. Those skilled in the art will understand, however, that other coupling mechanisms, such as press-fitting, shrink fitting, welding, or any other mechanical coupling method may also be employed.




The driver body


762


is sized to fit in the blade cavity


82


and is shown to include a keyway


774


, a slide surface


776


, a loading groove


778


and a tip portion


780


. The keyway


774


is illustrated to be a cut that is formed into the surface of the driver body


762


along its longitudinal axis. The fastener stop


102


that is formed into the internal cavity


100


in the nose guide


98


is disposed within the keyway


782


to guard against a situation wherein fasteners F feed rearwardly into the tool


10


. The slide surface


776


is generally flat and provides the driver body


762


with a relatively large surface that will consistently slide over the fasteners F that are loaded into the magazine assembly


20


. The tip portion


780


is formed at the front end of the driver body


762


and is operable for contacting the fasteners F and driving them into a workpiece. The loading groove


778


is cylindrically shaped and is formed along an axis that is skewed to the longitudinal axis of the driver blade


504


such that it intersects both the tip portion


780


and the slide surface


776


. The loading groove


778


is tapered such that it is deepest at the front of the driver blade


504


. The loading groove


778


ensures that only one fastener F is sheared from the remaining fasteners F in the magazine assembly


20


. The loading groove


778


also permits the fasteners F in the magazine assembly


20


to move upwardly toward the nose body


60


of the tool


10


prior to the time at which the driver blade


504


has stroked back to its rear-most (i.e., retracted) position to thereby minimize the lag time between the point at which the driver blade


504


has moved to its retracted position and the point at which the driver blade


504


can be moved forwardly to drive another fastener F.




With additional reference to

FIGS. 16 and 17

, the driver blade


504


and the piston assembly


502


, once coupled to one another, are inserted into the second cavity portion


614


of the hollow cavity


610


in the sleeve


510


. The diameter of the second cavity portion


614


is larger than the diameter of the piston assembly


502


(with the ring


722


in an expanded condition). A chamfer


790


is employed at the front of the second cavity portion


614


to facilitate the transition to the smaller-diameter first cavity portion


612


. With the exertion of light force onto the rear of the piston assembly


502


, the piston assembly


502


is moved forwardly in the hollow cavity


610


and into contact with the chamfer


790


. The chamfer


790


is operable for compressing the ring


722


to permit the piston assembly


502


to travel into the first cavity portion


612


.




Once assembled, the engine assembly


46


is placed into the housing cavity


174


such that the locating tab


664


is aligned to a tab slot


800


formed into the housing cavity


174


and the driver blade


504


is inserted through the driver blade aperture


410


in the piston bumper


152


and into the internal cavity


100


in the nose guide


98


. The engine assembly


46


is pushed forwardly into the housing cavity


174


to engage the guide assembly


522


against the guide stop


184


. In this position, the first and second housing seals


652


and


654


sealingly engage the guide bore


180


that is formed into the inside surface


182


of the outwardly tapering sidewall


172


. The first and second annular bumper portions


396


and


398


extend through the front face


810


of the sleeve


510


and into the hollow cavity


610


. The front face


820


of the front spring flange


530


sealingly contacts the second annular lip portion


408


on the piston bumper


152


. The cap assembly


44


is thereafter placed onto the rear end of the housing assembly


42


such that each of the longitudinally extending legs


662


contacts one of the foot tabs


434


. The foot tabs


434


cooperate with the longitudinally extending legs


662


to prevent the guide assembly


522


from moving along the longitudinal axis of the tool


10


. The sleeve


510


, however, is slidable within the guide assembly


522


, as will be discussed in greater detail, below.




Alternatively, the piston assembly


502


and driver blade


504


may be inserted into the housing cavity


174


such that the driver blade


504


is inserted through the driver blade aperture


410


in the piston bumper


152


and into the internal cavity


100


in the nose guide


98


. The cylinder assembly


500


is then loaded into the housing cavity


174


in the manner discussed above. A lead L formed into the front face


810


of the sleeve


510


that permits the ring


722


to be compressed so that the piston assembly


502


can travel rearwardly into the first cavity portion


612


of the hollow cavity


610


in the sleeve


510


.




Engine Operation




With reference to

FIGS. 10

,


14


and


16


, when the tool


10


has been coupled to a source of compressed air, the trigger assembly


48


maintains the trigger valve


130


in an unactuated state wherein compressed air is directed from the supply port


370


to the biasing port


372


where it enters the air gallery


680


at a point between the first and second housing seals


652


and


654


. Compressed air flows through the stepped-diameter body portion


660


and exits from the abutting flange


676


where it enters a sleeve return chamber


850


that is defined by the forward face


852


of the annular sleeve flange


552


, the rear guide seal


518


, the flange bore


670


, the body bore


672


, the front guide seal


520


and the first sleeve body portion


550


of the sleeve


510


. As the guide


650


is not movable within the housing


150


, the pressure of the air that is in the sleeve return chamber


850


is exerted against the front face


852


of the annular sleeve flange


552


to bias the sleeve


510


in a rearward direction.




The air inlet cavity


270


also provides compressed air to a sleeve extend chamber


860


that is defined by the rearward face


862


of the annular sleeve flange


552


, the rear guide seal


518


, the guide


650


, the second housing seal


654


, the portion of the outwardly tapering sidewall


172


that is situated rearwardly of the second housing seal


654


, the outer portion of the cap housing


420


that includes the annular exhaust port wall


438


, the cap flange seal


516


and the second sleeve body portion


554


of the sleeve


510


. Compressed air in the sleeve extend chamber


860


directs force to both the rearward face


862


of the annular sleeve flange


552


and the front face


864


of the flange portion


590


of the second sleeve body portion


554


of the sleeve


510


.




The forces that act on the annular sleeve flange


552


and the front face


864


of the flange portion


590


, in cooperation with the force that is exerted by the spring


528


, bias the sleeve


510


in a rearward direction into its retracted position such that the flat seal face


540


of the cap flange seal


516


sealingly engages the front face


866


of the annular exhaust port wall


438


.




With reference to

FIGS. 10 and 12

, when the sleeve


510


is in the retracted position, a primary exhaust chamber


870


is defined by the cap flange seal


516


, the inside surface


872


of the annular exhaust port wall


438


, the outer exhaust port seal


514


, the third sleeve body portion


556


of the sleeve


510


, the inner exhaust port seal


512


, the exhaust manifold


422


, the second sleeve body portion


554


of the sleeve


510


, the piston assembly


502


and the driver blade


504


. The position of the sleeve


510


relative to the cap assembly


44


is such that the air that is in the primary exhaust chamber


870


is permitted to flow between the third sleeve body portion


556


and exhaust manifold


422


, through the exhaust slots


470


in the exhaust manifold


422


and out the primary exhaust ports


450


in the exhaust button


440


where this air is vented to atmosphere.




With the sleeve


510


in the retracted position, a secondary exhaust chamber


880


is formed by the annular exhaust port wall


438


, the outer exhaust port seal


514


, the third sleeve body portion


556


of the sleeve


510


, the inner exhaust port seal


512


, the exhaust manifold


422


, the exhaust button


440


and the portion of the outer cap wall


430


between the annular exhaust port wall


438


and the exhaust button


440


. Air that is in the secondary exhaust chamber


880


is vented to the atmosphere through the primary exhaust ports


450


in the exhaust button


440


and through the secondary exhaust ports


452


in the portion of the outer cap wall


430


between the annular exhaust port wall


438


and the exhaust button


440


.




With reference to

FIGS. 12

,


14


and


18


, when the trigger assembly


48


is actuated to change the state of the trigger valve


130


to an actuated state, air in the sleeve return chamber


850


is vented through the trigger assembly


48


to the atmosphere. Consequently, the force that is exerted onto the rear face


862


of the annular sleeve flange


552


causes the sleeve


510


to slide forwardly relative to the housing assembly


42


. When the sleeve


510


slides in a forward direction, the seal between the cap flange seal


516


and the front face


866


of the annular exhaust port wall


438


is broken, permitting compressed air to flow through the rear exhaust slots


604


in the third sleeve body portion


556


of the sleeve


510


. As the area of the front surface


900


of the rear exhaust slots


604


is larger than the area of its rear surface


902


, the pressure of the air flowing through the rear exhaust slots


604


also tends to push the sleeve


510


in a forward direction. The piston bumper


152


checks forward travel of the sleeve


510


. More specifically, forward travel of the sleeve


510


is checked when the front face


810


of the sleeve


510


contacts the first annular lip portion


406


of the piston bumper


152


.




Simultaneous with the forward motion of the sleeve


510


, the inner exhaust port seal


512


slides forwardly by an equal amount to sealingly engage the outer circumference


910


of the exhaust manifold


422


at a point forward of the exhaust slots


470


to thereby prevent air from flowing to the atmosphere through the exhaust slots


470


. Pressure acts on the rear surface


920


of the piston assembly


502


to disengage the locking protrusion


744


in the second piston portion


732


from the groove


490


in the top bumper


424


. The pressure acts on the piston assembly


502


to drive the piston assembly


502


and the driver blade


504


forwardly through the first cavity portion


612


of the hollow cavity


610


in the sleeve


510


. Air in the first cavity portion


612


is compressed by the forward motion of the piston assembly


502


, causing it to be expelled from the hollow cavity


610


through the internal cavity


100


in the nose guide


98


, as well as through the front exhausting ports


562


and into a frontal air chamber


940


. The frontal air chamber


940


is defined by the first sleeve body portion


550


of the sleeve


510


, the front guide seal


520


, the guide


650


, the first housing seal


652


, the outwardly tapering wall


172


of the housing body


160


, the second annular lip portion


408


of the annular lip


392


in the piston bumper


152


, the front spring flange


530


and the front spring flange seal


532


.




The piston bumper


152


checks the forward motion of the sleeve


510


. Thereafter, the piston assembly


502


pushes the driver blade


504


forwardly so that the tip portion


780


drives a fastener F into a workpiece (not shown). With the piston bumper


152


also checks the forward motion of the piston assembly


502


and effectively seals against the front surface


770


of the piston assembly


502


to seal the frontal air chamber


940


. In this condition, the piston assembly


502


is positioned forwardly of the valve apertures


574


in the first sleeve body portion


550


of the sleeve


510


. Accordingly, if the pressure of the air in the portion of the hollow cavity


610


that is rearward of the piston assembly


502


is greater than the pressure of the air in the frontal air chamber


940


, the compensating valve


524


permits air to flow through the sleeve


510


and into the frontal air chamber


940


so as to balance the air pressure that is acting on the front and rear surfaces


770


and


920


of the piston assembly


502


. The compensating valve


524


, however, is a one-way valve that does not permit air to flow from the frontal air chamber


940


through the valve apertures


574


and into the hollow cavity


610


.




Referring back to

FIGS. 10

,


12


,


14


and


16


, when the state of the trigger valve


130


is changed to its unactuated state, compressed air is once again routed to the sleeve return chamber


850


where it applies a force against the front face


852


of the annular sleeve flange


552


. The balance of the forces on the sleeve


510


is such that the sleeve


510


is pushed in a rearward direction until the cap flange seal


516


sealingly engages the front face


866


of the annular exhaust port wall


438


. Air in the primary and secondary exhaust chambers


870


and


880


is then vented to the atmosphere in the manner discussed above.




The piston assembly


502


, immediately prior to the exhausting of the air in the primary and secondary exhaust chambers


870


and


880


, was such that it remained in sealed engagement with the piston bumper


152


. When the air in the primary exhaust chamber


870


is vented to the atmosphere, however, the pressure in the frontal air chamber


940


generates a force on the front surface


770


of the piston assembly


502


that exceeds the force that is acting on its rear face


920


. As mentioned above, the compensating valve


524


is a one-way valve that prevents air from flowing through the valve apertures


574


and into the hollow cavity


610


and as such, the pressure of the air to the rear of the piston assembly


502


is less than the pressure of the air in the frontal air chamber


940


. Accordingly, the pressure acting on the front surface


770


of the piston assembly


502


drives the piston assembly


502


rearwardly until the locking protrusion


744


in the second piston portion


732


engages the groove


490


in the top bumper


424


.




Those skilled in the art will understand that while the above-described configuration of the engine assembly


46


results in a relatively lighter-weight tool as compared with pneumatic fastening devices that employ a conventional head valve, the reduction in the weight of the tool


10


does not come at the expense of increased recoil that is felt by the tool operator. In this regard, the felt force that is exerted onto the cap assembly


44


when a fastener F is driven into a workpiece is counteracted by the felt force that is exerted by the sliding of the sleeve


510


in a forward direction.




Magazine Assembly




The magazine assembly


20


is shown to include a magazine body assembly


1000


, a follower structure


1002


, a follower spring


1004


and a magazine endcap assembly


1006


. The magazine body assembly


1000


includes a magazine housing


1010


, a pair of guide structures


1012




a


and


1012




b


and a coupling bracket


1014


. In the example illustrated, the magazine housing


1010


is extruded from a lightweight material, such as aluminum and includes a wall member


1020


that defines a fastener head portion


1022


, a follower housing portion


1024


, a pair of guide housing portions


1026


and a fastener body portion


1028


.




The fastener head portion


1022


is generally rectangular in shape, defining a fastener head chamber


1030


that is open at its top and bottom ends so as to permit the head portion H of the fasteners F to travel through the fastener head portion


1022


. The fastener head portion


1022


is also open along a portion of one of its sides


1032


so as to permit the follower structure


1002


to travel upwardly within the magazine housing


1010


. With additional reference to

FIG. 21

, a threaded fastener


1034


is threadably engaged to the wall member


1020


, forming a contact surface


1036


that checks the upward travel of the follower structure


1002


.




As shown in

FIGS. 19

,


20


and


22


, the follower housing portion


1024


is coupled to the forward side of the fastener head portion


1022


and defines a generally rectangular follower cavity


1040


that is sized to receive the follower structure


1002


and the follower spring


1004


. A slot


1042


is formed into the rear surface


1044


of the follower housing portion


1024


. The slot


1042


interconnects the follower cavity


1040


to the fastener head chamber


1030


. An L-shaped pin aperture


1050


is formed into a side of the follower housing portion


1024


. The L-shaped pin aperture


1050


includes a relatively narrow first portion


1052


that extends generally parallel the longitudinal axis of the follower housing portion


1024


and a second portion


1054


that is skewed to the first portion


1052


. The L-shaped pin aperture


1050


will be discussed in greater detail, below.




In

FIGS. 19 and 20

, each guide housing portion


1026


is shown to include a pair of spaced apart and arcuate protrusions


1060




a


and


1060




b


that are coupled to the wall member


1020


. The arcuate protrusions


1060




a


and


1060




b


cooperate with the wall member


1020


to define a guide structure cavity


1062


that extends over the length of the magazine housing


1010


and which is configured to receive one of the guide structures


1012




a


and


1012




b


. In the particular embodiment illustrated, the guide structure cavity


1062


includes a first cavity portion


1064


that is generally cylindrically shaped and located proximate the follower housing portion


1024


, and a second cavity portion


1066


that is shaped as a generally flat void that is generally tangent to the cylindrically shaped first cavity portion


1064


.




The fastener body portion


1028


is generally U-shaped, being coupled to the forward portion of the pair of guide housing portions


1026


. The fastener body portion


1028


includes a U-shaped fastener body cavity


1070


that is configured to receive the body B of the fasteners F. A plurality of oval windows


1072


are formed into the sides


1074


of the fastener body portion


1028


which permit the tool operator to monitor the quantity of fasteners F that are housed in the magazine assembly


20


, as well as to reduce the overall weight of the magazine assembly


20


.




As guide structures


1012




a


and


1012




b


are generally identical in construction, reference numerals may occasionally be shown on only of the guide structure


1012




a


and


1012




b


. Those skilled in the art will understand, however, that guide structure


1012




b


is a mirror image of guide structure


1012




a


. In the embodiment illustrated in

FIGS. 19

,


20


and


23


, each of the guide structures


1012




a


and


1012




b


includes a cylindrically-shaped guide port


1100


, first and second retention tabs


1102


and


1104


, respectively, an intermediate member


1106


and an end member


1108


. The guide port


1100


is generally hollow, having an outside diameter that is sized to slip fit into the first cavity portion


1064


of an associated one of the guide housing portions


1026


and an inside diameter that is to engage an associated one of the magazine guide posts


66


. The first retention tab


1102


is coupled to the guide port


1100


on one side and to the intermediate member


1106


on the opposite side. The second retention tab


1104


is coupled to the intermediate member


1106


on the side opposite the first retention tab


1102


. The intermediate member


1106


is sized to fit between the arcuate protrusions


1060




a


and


1060




b


in the guide housing portion


1026


as well as to space the first and second retention tabs


1102


and


1104


apart from one another by a predetermined distance that permits the first and second retention tabs


1102


and


1104


to engage the arcuate protrusions


1060




a


and


1060




b


when the guide structures


1012




a


and


1012




b


are inserted into the guide structure cavities


1062


. The inner surface


1110


of the second retention tab


1104


extends inwardly further toward the centerline


1112


of the magazine housing


1010


than the inside surfaces of the U-shaped fastener body cavity


1070


so as to form a wear surface


1114


against which the body B of the fastener F is permitted to rub. The end member


1108


is coupled to the end of the guide structures


1012




a


and


1012




b


opposite the end to which the guide port


1100


is coupled. The end member


1108


is configured to abut the ends of the arcuate protrusions


1060




a


and


1060




b


so as to prevent the guide structures


1012




a


and


1012




b


from moving upwardly out of the top of the magazine housing


1010


.




In

FIGS. 24 and 25

, the coupling bracket


1014


is shown to have a pair of threaded bushings


1200


and a bracket structure


1202


having a pair of mounting flanges


1204


and a U-shaped body portion


1206


that is coupled to one of the mounting flanges


1204


at each of its opposite ends. Each of the threaded bushings


1200


is coupled to one of the mounting flanges


1204


. The mounting flanges


1204


abut the side of the follower housing portion


1024


and threaded fasteners


1210


(

FIG. 2

) are employed to engage the threaded bushings


1200


to fixedly but removably couple the coupling bracket


1014


to the magazine housing


1010


.




The U-shaped body portion


1206


includes a base


1220


and a plurality of legs


1222


, with each of the legs


1222


coupling a side of the base


1220


to an associated one of the mounting flanges


1204


. The base


1220


includes a slotted pin aperture


1230


that includes a circular portion


1232


, a slotted portion


1234


that is spaced apart from the circular portion


1232


, and a necked-down slotted portion


1236


having a width that is smaller than that of the slotted portion


1234


and which interconnects the circular and slotted portions


1232


and


1234


. The circular portion


1232


is sized to receive the head portion


322


of the clamp pin


300


, the slotted portion


1234


is sized to slidingly receive the first body section


324


of the clamp pin


300


, and the necked-down slotted portion


1236


is sized to receive the second body section


326


of the clamp pin


300


but not the first body section


324


. With specific reference to

FIG. 25

, the back side of the base


1220


is illustrated in pertinent detail. The end of the slotted portion


1234


is shown to include a conical detent


1238


which is configured to confront the frusto-conical abutting face


330


of the head portion


322


of the clamp pin


300


.




With reference to

FIGS. 19

,


20


and


27


through


32


, the follower structure


1002


is illustrated to have a follower body


1300


, a front guide tab


1302


, a lock-out dog


1304


, a loading cam


1306


, a follower guide


1308


and an actuating lever


1310


. The follower body


1300


is generally U-shaped, having a base


1320


and a pair of follower legs


1322




a


and


1322




b


. The lock-out dog


1304


extends upwardly from the base


1320


in a direction opposite that of the follower legs


1322




a


and


1322




b


. The front guide tab


1302


is also coupled to the base


1320


but extends upwardly and forwardly therefrom in the same plane as the base


1320


. Accordingly, when the follower structure


1002


is installed to the magazine housing


1010


, the front guide tab


1302


extends forwardly from the follower housing portion


1024


, past the pair of guide housing portions


1026


and into the fastener body portion


1028


where the U-shaped tip portion


1330


of the front guide tab


1302


supports the body B of the fasteners F.




The loading cam


1306


is formed into follower leg


1322




a


and includes a first loading cam portion


1350


, a second loading cam portion


1352


and an unloading cam portion


1354


. The first loading cam portion


1350


is a tapered ramp that extends outwardly and upwardly from the distal end of the follower leg


1322




a


. The second loading cam portion


1352


includes an oval follower capturing portion


1360


, a downwardly and forwardly extending intermediate portion


1362


and a forwardly and upwardly extending catch portion


1364


and a catch aperture


1368


that is formed at the lower-most portion of the catch portion


1364


. The follower capturing portion


1360


and the intermediate portion


1362


are formed into a first side of the follower leg


1322




a


at a first depth, and the catch portion


1364


is formed into the first side of the follower leg


1322




a


at a second depth that is greater than the first depth. The unloading cam portion


1354


is a generally flat portion of the front surface


1370


of the follower leg


1322




a.






The follower guide


1308


is formed onto the outside surface of follower leg


1322




b


. The follower guide


1308


includes a V-shaped flange


1380


, an end member


1382


and a connector portion


1384


that couples the V-shaped flange


1380


and the end member


1382


. The connector portion


1384


is configured to fit into the slot


1042


in the follower housing portion


1024


such that the V-shaped flange


1380


and the end member


1382


confront the rear inside surface


1044


and the rear outside surface


1388


, respectively, of the follower housing portion


1024


.




The actuating lever


1310


extends outwardly from the end member


1382


and thereafter bends inwardly toward the follower legs


1322




a


and


1322




b


. The distal end of the actuating lever


1310


forms an engagement surface


1390


that is configured for receiving an input from the tool operator's thumb. A protrusion


1392


that is configured to contact the contact surface


1036


in the fastener head portion


1022


is also formed onto the actuating lever


1310


.




With reference to

FIGS. 19

,


20


,


29


,


30


and


33


, the follower spring


1004


is illustrated to include a spring hook


1400


, a coiled, flat band spring


1402


, a cylindrically-shaped spring roller body


1404


and a spring roller pin


1406


. The spring roller pin


1406


extends through and rotatably supports the spring roller body


1404


. The band spring


1402


is a type of torsion spring, being coupled to and wound around the spring roller body


1404


. The free end of the band spring


1402


is coupled to the spring hook


1400


. Each end of the spring roller pin


1406


is set into a generally U-shaped spring roller slot


1410


that is formed into each inside surface of the follower legs


1322




a


and


1322




b


to couple the follower spring


1004


to the follower structure


1002


.




When the follower structure


1002


is disposed within the follower housing portion


1024


, the band spring


1402


is unwound to permit the C-shaped spring hook


1400


to be engaged to the side of the follower housing portion


1024


opposite the side in which the L-shaped pin aperture


1050


is formed. The torsion exerted by the band spring


1402


is converted to a force that is exerted through the spring roller pin


1406


to the follower structure


1002


, thereby biasing the follower structure


1002


in an upward direction toward the spring hook


1400


.




In the particular embodiment illustrated in

FIGS. 1

,


19


and


35


through


45


, the magazine endcap assembly


1006


includes a molded end cap structure


1600


, a crush tube


1602


, a pivot structure


1604


, a cam follower


1606


, a cam follower spring


1608


and a thrust member


1610


. The end cap structure


1600


is configured to mate against the bottom of the magazine housing


1010


to close off the follower housing portion


1024


and the fastener body portion


1028


.




The end cap structure


1600


includes a bushing trunnion


1620


for receiving the crush tube


1602


, a fastener trunnion


1622


for receiving a fastener


1623




a


(

FIG. 1

) that couples the nose


1623




b


of the end cap structure


1600


to the fastener body portion


1028


and a pair of pivot trunnions


1624


for receiving the pivot structure


1604


, which is illustrated to be a threaded fastener


1626


that is secured to the end cap structure


1600


via a threaded nut


1628


in the example provided. The crush tube


1602


, which is retained by the bushing trunnion


1620


, prevents the end cap structure


1600


form being overstressed as well as the follower housing portion


1024


from being deformed as a result of the clamping force that is exerted by the threaded fastener


1630


(

FIG. 1

) that couples the end cap structure


1600


to the follower housing portion


1024


.




The end cap structure


1600


also includes a follower directing wall


1640


, a thrust flange


1642


and a spring flange


1644


. The follower directing wall


1640


extends upwardly from the base


1646


of the end cap structure


1600


and includes a ramped portion


1650


, which tapers outwardly and downwardly from the top end


1652


of the follower directing wall


1640


, and a generally flat portion


1654


that interconnects the ramped portion


1650


to the base


1646


of the end cap structure


1600


. The spring flange


1644


is located proximate one of the pivot trunnions


1624


, extending upwardly from the base


1646


of the end cap structure


1600


behind one of the pivot trunnions


1624


. The thrust flange


1642


is located between the spring flange


1644


and the follower directing wall


1640


and includes a first U-shaped aperture


1660


that is configured to receive the pivot structure


1604


and a second U-shaped aperture


1662


that is configured to receive the hollow thrust member


1610


.




In the particular embodiment illustrated, the cam follower


1606


includes a lever


1670


and a follower hook


1672


. The lever


1670


includes a slotted pivot aperture


1680


that is sized to receive and rotate as well as pivot in a lateral (side-to-side) direction on a portion of the pivot structure


1604


. The lever


1670


extends beyond the slotted pivot aperture


1680


to form a spring follower hook


1672


that can be employed during the assembly of the magazine endcap assembly


1006


. The follower hook


1672


includes a cylindrical body portion


1690


that is coupled to the distal end of the lever


1670


and a leg member


1692


that is coupled to the outer end of the body portion


1690


and which extends downwardly from the body portion


1690


generally parallel to the lever


1670


. The outside face


1694


of the leg member


1692


is heavily chamfered such that the leg member


1692


terminates at a rounded tip portion


1696


. The intersection between the body portion


1690


and the leg member


1692


is undercut by a radius


1698


.




The cam follower spring


1608


is illustrated to be a combination compression and torsion spring having a spring body


1700


that wraps around a portion of the pivot structure


1604


, a bent end


1702


for contacting the front face of the lever


1670


and a straight end


1704


for contacting the spring flange


1644


. The cam follower spring


1608


is operable for exerting a rotational biasing force onto the cam follower


1606


which biases the cam follower


1606


toward the rear of the tool


10


. The cam follower spring


1608


is also operable for exerting a lateral force onto the cam follower


1606


which biases the cam follower


1606


toward the thrust member


1610


.




The pivot structure


1604


is positioned through the pivot trunnion


1624


that is adjacent the spring flange


1644


. The cam follower spring


1608


is positioned over a portion of the pivot structure


1604


such that the straight end


1704


is in contact with the spring flange


1644


. The cam follower


1606


is positioned into the end cap structure


1600


such that the lever


1670


will contact the thrust member


1610


and the follower hook


1672


will be proximate the follower directing wall


1640


. The spring follower hook


1672


of the cam follower


1606


is employed to lift the bent end


1702


of the cam follower spring


1608


onto the lever


1670


. The pivot structure


1604


is then pushed through the slotted pivot aperture


1680


. The hollow thrust member


1610


, which is a washer in the embodiment illustrated, is positioned in the second U-shaped aperture


1662


in the thrust flange


1642


and the pivot structure


1604


is pushed entirely through the end cap structure


1600


and secured in place with the threaded nut


1628


.




With additional reference to

FIGS. 27

,


31


and


32


, when fasteners F are to be loaded into the magazine assembly


20


, the tool operator presses the engagement surface


1390


of the actuating lever


1310


to move the follower structure


1002


downward toward the end cap structure


1600


. The ramped portion


1650


of the follower directing wall


1640


directs the follower leg


1322




a


of the follower structure


1002


toward the cam follower


1606


and the flat portion


1654


of the follower directing wall


1640


ensure that proper contact is established and maintained between the loading cam


1306


and the cam follower


1606


.




When the first loading cam portion


1350


of the loading cam


1306


contacts the leg member


1692


of the follower hook


1672


on the cam follower


1606


, the ramp of the first loading cam portion


1350


pushes the follower hook


1672


in a side-to-side motion along the axis of the pivot structure


1604


in the direction of Arrow R (FIG.


43


), permitting the leg member


1692


to travel over the first loading cam portion


1350


and into the oval follower capturing portion


1360


of the second loading cam portion


1352


of the loading cam


1306


. With the leg member


1692


being positioned in the oval follower capturing portion


1360


, the follower structure


1002


cannot be moved further down the magazine housing


1010


. When pressure on the engagement surface


1390


of the actuating lever


1310


is released, the force generated by the follower spring


1004


is employed to lift the follower structure


1002


within the magazine housing


1010


so as to simultaneously cause the cam follower


1606


to pivot about the axis of the pivot structure


1604


, thereby permitting the leg member


1692


to travel through the intermediate portion


1362


and into the catch portion


1364


of the second loading cam portion


1352


of the loading cam


1306


. When the leg member


1692


is positioned in the catch portion


1364


of the loading cam


1306


, the leg member


1692


extends through the catch aperture


1368


and around the follower leg


1322




a


of the follower structure


1002


as illustrated in

FIG. 32



a


, thereby securely coupling the cam follower


1606


to the follower structure


1002


and inhibiting upward travel of the follower structure


1002


within the magazine housing


1010


. In this condition, fasteners F may be readily loaded into the magazine assembly


20


.




If the magazine assembly


20


is not already coupled to the fastening tool portion


30


, this operation is performed next. This is accomplished by positioning the top end of the magazine assembly


20


relative to the nose assembly


40


such that the holes in the guide ports


1100


are proximate an associated one of the magazine guide posts


66


, the stop member


134


on the trigger lever


54


is positioned directly above the first portion


1052


of the L-shaped pin aperture


1050


, and the head portion


322


of the clamp pin


300


is engaged to the circular portion


1232


of the slotted pin aperture


1230


in the base


1220


of the bracket structure


1202


. The actuating cam


306


is then pushed toward the clamp boss


252


to compress the compression spring


302


and extend the clamp pin


300


in an outward direction so that the second body section


326


of the clamp pin


300


extends through the slotted pin aperture


1230


. With the clamp pin


300


in this condition, the magazine assembly


20


is slid upwardly until the clamp pin


300


is fully positioned into the slotted portion


1234


of the slotted pin aperture


1230


. Simultaneously, the guide ports


1100


are slid further onto the magazine guide posts


66


so that the top of the magazine assembly


20


cannot pivot relative to the nose assembly


40


and the stop member


134


on the trigger lever


54


is disposed in the second portion


1054


of the L-shaped pin aperture


1050


.




Thereafter, the tool operator releases the actuating cam


306


, causing the compression spring


302


to retract the clamp pin


300


somewhat so that the first body section


324


of the clamp pin


300


is disposed within the slotted portion


1234


of the slotted pin aperture


1230


. In this condition, the parallel flats


328


that are formed onto the first body section


324


abut the parallel sides of the slotted portion


1234


of the slotted pin aperture


1230


, thereby permitting the magazine assembly


20


to be slid along an axis defined by the magazine guide posts


66


and the slotted portion


1234


of the slotted pin aperture


1230


. The magazine assembly


20


is pushed upwardly into contact with the magazine flange


64


that is formed into the nose structure


50


. The actuating cam


306


is then pivoted to place the leg portion


352


in contact with the flat contact surface


344


. More specifically, the frusto-conical abutting face


330


of the head portion


322


of the clamp pin


300


engages the conical detent


1238


that is formed into the end of the slotted portion


1234


to both locate the magazine assembly


20


relative to the tool portion


30


as well as to mechanically lock the clamp pin


300


to the coupling bracket


1014


.




In this condition, the compression spring


302


exerts a clamping force that is transmitted through the clamp pin


300


to fixedly but removably couple the coupling bracket


1014


to the clamp boss


252


. The magazine stabilizing tabs


62


extend downwardly from the magazine flange


64


and abut the opposite sides of the fastener body portion


1028


of the magazine housing


1010


to inhibit excessive rotation of the magazine assembly


20


relative to the nose assembly


40


.




With the magazine assembly


20


attached, the fasteners F are fed into the magazine assembly


20


such that the body B of the fasteners F enter the follower cavity


1040


via the slot


1042


. Typically, the fasteners F are collated (usually at an angle of 20° or 31°) in “sticks”, which permits the magazine assembly


20


to be loaded relatively rapidly.




The follower structure


1002


is released from the cam follower


1606


by pressing downwardly on the engagement surface


1390


of the actuating lever


1310


. The body portion


1690


of the follower hook


1672


rides on the upper surface of the forwardly and upwardly extending catch portion


1364


, causing the cam follower


1606


to rotate forwardly. The simultaneous downward movement of the follower structure


1002


and the forward rotation of the cam follower


1606


continues until the leg member


1692


slips out of the catch portion


1364


and the body portion


1690


of the follower hook


1672


slides onto the unloading cam portion


1354


of the loading cam


1306


. As the leg member


1692


of the follower hook


1672


is not contacting the side of the leg


1322




a


of the follower structure


1002


, the follower spring


1004


exerts a force against the lever


1670


that pushes the follower hook


1672


in a side-to-side motion so that the lever


1670


abuts the thrust member


1610


. With the body


1690


of the follower hook


1672


engaged against the unloading cam portion


1354


of the loading cam


1306


, the body


1690


of the follower hook


1672


prevents the cam follower


1606


from engaging the follower structure


1002


and the upward motion of the follower structure


1002


is controlled by the follower spring


1004


. The upward movement of the follower structure


1002


brings the tip portion


1330


of the front guide tab


1302


into contact with the bottom-most fastener F in the magazine assembly


20


which urges the fasteners F upwardly and into the nose assembly


40


. The force exerted by the follower structure


1002


onto the fasteners F, along with the configuration of the fastener head portion


1022


, ensures that fasteners F will not slip rearwardly out of the magazine assembly


20


during the operation of the tool


10


.




As discussed above, the tool operator must push the contact trip


52


against the workpiece to cause the trigger lever


54


to push the secondary trigger


128


in to contact with the trigger valve


130


to permit the state of the trigger valve


130


to be changed. With the magazine assembly


20


fully engaged against the magazine flange


64


, the stop member


134


on the trigger lever


54


is free to move in a direction parallel to the longitudinal axis of the tool


10


(i.e., rearwardly-forwardly) within the second portion


1054


of the L-shaped pin aperture


1050


.




In the event of a “jam” condition wherein fasteners F have not fed properly through the nose assembly


40


, the tool operator need only rotate the actuating cam


306


such that its base portion


350


is abutted against the flat contact surface


344


to release the clamping force that is exerted through the clamp pin


300


. The magazine assembly


20


may then be slid downwardly from the magazine flange


64


to permit the tool operator to service the nose assembly


40


. The magazine assembly


20


, however, is constrained by the magazine guide posts


66


and the clamp pin


300


so that it can only move in a predetermined linear direction. The predetermined linear direction is cooperatively defined by the magazine guide posts


66


, which remain engaged in the holes


1800


in the guide ports


1100


, and the first body section


324


of the clamp pin


300


, which remains engaged in the slotted portion


1234


of the slotted pin aperture


1230


. Downward movement of the magazine assembly


20


is checked when the first body section


324


of the clamp pin


300


contacts the necked-down slotted portion


1236


of the slotted pin aperture


1230


. Accordingly, the nose assembly


40


may be serviced without completely removing the magazine assembly


20


from the magazine flange


64


. Furthermore, when the magazine assembly


20


is moved downwardly into this condition, the stop member


134


is moved out of the second portion


1054


of the L-shaped pin aperture


1050


and into the first portion


1052


of the L-shaped pin aperture


1050


. With the stop member


134


located in this manner, rearward motion of the contact trip


52


relative to the nose body


60


is limited such that the stop member


134


contacts the rearward edge


1820


of the first portion


1052


of the L-shaped pin aperture


1050


, thereby preventing the trigger lever


54


from pushing the secondary trigger


128


sufficiently rearward so that the state of the trigger valve


130


cannot be changed (i.e., actuated). Accordingly, the stop member


134


and the L-shaped pin aperture


1050


cooperate to selectively prevent the trigger valve


130


from being actuated depending upon the position of the magazine assembly


20


relative to the magazine flange


64


.




Those skilled in the art will understand that as fasteners F are dispensed from the tool


10


, the follower spring


1004


will force the follower structure


1002


in an upwardly direction so as to continue to feed fasteners F into the nose body


60


. When the magazine assembly


20


is empty of fasteners F, the follower structure


1002


will be raised within the magazine housing


1010


to a point wherein the lock-out dog


1304


extends through the lock-out dog aperture


90


that is formed into the magazine flange


64


so that it inhibits sufficient rearward motion of the contact trip


52


so as to prevent the trigger lever


54


from changing the state of the trigger valve


130


. Accordingly, the lock-out dog


1304


inhibits the tool


10


from cycling when the magazine assembly


20


is empty of fasteners F and coupled to the magazine flange


64


.




In an alternate embodiment of the present invention illustrated in

FIGS. 46 and 47

, the nose assembly


40


includes a pivoting lock-out tab


2000


that is rotatably coupled to the nose structure


50


and pivotable between a first position, which is illustrated in

FIG. 47

, that permits the contact trip


52


to move rearwardly a sufficient amount that permits the trigger lever


54


to change the state of the trigger valve


130


, and a second position, which is shown in

FIG. 46

, that inhibits rearward motion of the contact trip


52


by an amount wherein the trigger lever


54


cannot change the state of the trigger valve


130


. As illustrated in

FIG. 47

, when the magazine assembly


20


abuts the magazine flange


64


, the top surface


2010


of the magazine housing


1010


contacts the lock-out tab


2000


and rotates it into the first position. When the magazine assembly


20


is not abutted against the magazine flange


64


as illustrated in

FIG. 46

, however, the lock-out tab


2000


is rotated by a torsion spring (not specifically shown) into the second position to prevent the tool


10


from being cycled.




Those skilled in the art will understand that the configuration of the slotted pin aperture and the clamp pin may be somewhat different from that which is shown in

FIGS. 9



b


and


24


. For example, the clamp pin and the slotted pin aperture may be formed as is illustrated in

FIGS. 48 and 49

, respectively. In this embodiment, the clamp pin


300


′ is substantially identical to the clamp pin


300


except for the omission of the parallel flats


328


from the first body section


324


′.




The configuration of the slotted pin aperture


1230


′, however, is substantially different from the configuration of the slotted pin aperture


1230


. In this regard, the slotted pin aperture


1230


′ includes a circular portion


1232


′, which is sized to receive the head


322


′ of the clamp pin


300


′ therethrough, and a slotted portion


1234


′, which has a body portion


1234




a


with a first end


1234




b


and a second end


1234




c


. The first end


1234




b


interconnects the body portion


1234




a


to the circular portion


1232


′ in a dog-legged manner. In this regard, the first end


1234




b


defines a protrusion


1234




d


that necessitates that the coupling bracket


1014


′ and the clamp pin


300


′ be moved laterally relative to one another to permit the clamp pin


300


′ to move around the protrusion


1234




d


and into the circular portion


1232


′. The first end


1234




b


and the protrusion


1234




d


may be sized so as to permit the first body section


324


′ of clamp pin


300


′ to pass around the dog-leg and into the circular portion


1232


′, or, as is presently preferred may be sized to allow only permit the second body section


326


′ of the clamp pin


300


′ to pass around the dog-leg and into the circular portion


1232


′. The second end


1234




c


of the body portion


1234




a


is similar in configuration to the end of the slotted portion


1234


, in that it includes a conical detent


1238


. The second end


1234




c


, however, defines one or more protrusions


1234




e


which are relatively narrower than the body portion


1234




a


so as to admit therethrough only the second body section


326


′ of the clamp pin


300


′.




This alternate construction of the clamp pin


300


′ and the coupling bracket


1014


′ is advantageous in that it simplifies the construction of the clamp pin


300


′ (relative to the clamp pin


300


), and renders the connection between the clamp pin


300


′ and the coupling bracket


1014


′ more secure.




While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the foregoing description and the appended claims.



Claims
  • 1. In a magazine assembly for holding and progressively dispensing a plurality of fasteners, a feed mechanism for feeding the fasteners through a hollow cavity in a magazine housing toward a dispensing end of the magazine housing, the feed mechanism comprising:a fastener follower that is configured to support the fasteners in the magazine housing, the fastener follower including a cam device; and a cam follower coupled to the magazine housing at an end opposite the dispensing end, the cam follower operable for alternately engaging and disengaging the cam device, the fastener follower being restrained from movement toward the dispensing end of the magazine housing when the cam follower is engaged to the cam device; wherein disengagement of the cam follower from the cam device occurs solely from downward motion of the fastener follower relative to the cam follower beyond a predetermined disengaging point.
  • 2. The feed mechanism of claim 1, further comprising a device for biasing the fastener follower toward the dispensing end of the magazine housing.
  • 3. The feed mechanism of claim 1, wherein engagement of the cam follower to the cam device occurs via movement of the fastener follower toward the cam follower beyond a predetermined point followed by movement of the fastener follower away from the cam follower.
  • 4. The feed mechanism of claim 1, wherein the cam follower includes a lever that is pivotable in first and second orthogonal directions, the lever pivoting in the first and second orthogonal directions in response to contact with the cam device to engage the cam follower to the cam device, the lever pivoting in at least the first orthogonal direction when disengaging the cam device.
  • 5. The feed mechanism of claim 4, wherein the lever includes a slotted aperture through which a pivot structure extends, the lever pivoting on the pivot structure in the first and second orthogonal directions.
  • 6. The feed mechanism of claim 5, wherein the lever is biased in a predetermined rotational direction and a predetermined lateral direction by a biasing device.
  • 7. The feed mechanism of claim 6, wherein the biasing device is a combination compression and torsion spring.
  • 8. The feed mechanism of claim 4, wherein the cam follower further includes a hook for engaging the cam device.
  • 9. The feed mechanism of claim 8, wherein the hook has a leg member that extends into a hole in the cam device when the cam follower is engaged to the cam device.
  • 10. The feed mechanism of claim 8, wherein the hook is generally L-shaped.
  • 11. A magazine assembly for holding and progressively dispensing a plurality of fasteners, the magazine assembly comprising:a magazine housing having a hollow cavity that is configured to hold the fasteners, the magazine housing having a dispensing end; and a feed mechanism for selectively urging the fasteners toward the dispensing end, the feed mechanism having: a fastener follower for supporting the fasteners in the magazine housing, the fastener follower including a cam device; a biasing device for biasing the follower toward the dispensing end of the magazine assembly; an end cap structure that is coupled to an end of the magazine housing opposite the dispensing end; and a cam follower pivotably coupled to the end cap structure and movable between an engaged condition, wherein the cam follower is engaged to the cam device to inhibit movement of the fastener follower toward the dispensing end, and a disengaged condition, wherein movement of the fastener follower toward the dispensing end is not inhibited by the cam follower; wherein disengagement of the cam follower from the cam device occurs solely from downward motion of the fastener follower relative to the cam follower beyond a predetermined disengaging point; and wherein engagement of the cam follower to the cam device occurs via movement of the fastener follower toward the cam follower beyond a predetermined engaging point followed by movement of the fastener follower away from the cam follower.
  • 12. The magazine assembly of claim 11, wherein contact between the cam device and the cam follower causes the cam follower to pivot about first and second orthogonal directions prior to engaging the cam device.
  • 13. The magazine assembly of claim 12, wherein the cam device includes a first loading portion and a second loading portion, the first loading portion consisting of a tapered wedge for pushing the cam follower in a lateral direction into abutment with a lateral side of the cam device, the second loading portion including a recessed follower capturing portion and a catch aperture, the recessed follower capturing portion inhibiting movement of the fastener follower toward the end of the magazine housing opposite the dispensing end when the cam follower is abutted against the lateral side of the cam device and thereafter guiding the cam follower into engagement with the catch aperture in response to movement of the fastener follower toward the dispensing end.
  • 14. The magazine assembly of claim 13, wherein the cam device further includes an unloading portion, the unloading portion having a sloped surface for contacting the cam follower in response to movement of the cam device from the engaged condition toward the opposite end of the magazine housing, the sloped surface of the unloading portion pushing the cam follower in a rotational direction away from the recessed follower capturing portion, the cam follower thereafter pivoting laterally toward the cam device such that movement of the cam device toward the dispensing end will not cause the cam follower to engage the second loading portion.
  • 15. The magazine assembly of claim 14, wherein the cam follower includes a generally L-shaped hook having a body portion and a leg, the leg extending from the body portion and extending into the catch aperture when the cam follower is engaged to the cam device.
  • 16. The magazine assembly of claim 11, wherein the fastener follower includes a generally U-shaped follower guide having a pair of spaced apart legs, the cam device being coupled to a first one of the legs.
  • 17. The magazine assembly of claim 16, wherein the fastener follower is unitarily formed.
  • 18. The magazine assembly of claim 16, wherein an actuating lever is coupled to a second one of the legs, the actuating lever being configured to receive a manual input for positioning the cam device in the engaged condition and releasing the cam device from the engaged condition.
  • 19. The magazine assembly of claim 16, wherein one of the legs includes a V-shaped flange for confronting a portion of the magazine housing, the V-shaped flange and the portion of the magazine housing cooperating to guide the fastener follower as the fastener follower is moved between the dispensing end and the opposite end of the magazine housing.
  • 20. A fastening tool for holding a plurality of fasteners and selectively setting a first one of the fasteners into a workpiece, the fastening tool comprising:a fastening tool portion having a handle, a clamp mechanism, and a nose structure, the handle being configured to be gripped by an operator when using the fastening tool, the clamp mechanism being coupled to the handle and including a clamp pin with a head portion and a body portion, the clamp pin being movable between an engaged condition and a disengaged condition, the nose structure including a magazine flange; and a magazine assembly having an upper surface that is configured to abut a bottom surface of the magazine flange, the magazine assembly further including a magazine housing and a coupling bracket, the coupling bracket coupled to the magazine housing and including a slotted coupling aperture having a first portion, which is sized larger than the head portion of the clamp pin, a second portion, which is sized to engage the head portion, and a slotted portion interconnecting the first and second portions of the slotted coupling aperture, the slotted portion of the slotted coupling aperture being sized larger than the body portion of the clamp pin and smaller than the head portion of the clamp pin; the magazine assembly being positionable relative to the fastening tool portion in an uncoupled condition, wherein the magazine assembly is separated from the fastening tool portion; the magazine assembly being positionable relative to the fastening tool portion in a coupled condition, wherein the magazine assembly is fixed to the fastening tool portion such that the clamp pin is disposed in the second portion of the slotted coupling aperture and the clamp mechanism is positioned in the engaged position and generating a clamping force that is applied through the head portion of the clamp pin and against the coupling bracket to thereby secure the magazine assembly to the handle; the magazine assembly also being positionable relative to the fastening tool portion in a semi-coupled condition, wherein the clamp mechanism is positioned in the disengaged position and the clamp pin is disposed in the slotted portion of the slotted coupling aperture to thereby permit the magazine assembly to be slid relative to the fastening tool portion, the slotted portion being sized to limit sliding movement of the magazine assembly in a predetermined direction.
  • 21. The fastening tool of claim 20, wherein the first portion, the second portion and the slotted portion are each disposed about a common axis.
  • 22. The fastening tool of claim 20, wherein the body portion includes a first body portion and a second body portion, the first body portion being coupled at opposite ends to the head portion and the second body portion, the second body portion being sized relatively smaller than the first body portion and wherein an intersection between the slotted portion and the second portion is sized smaller than the first body portion such that only the second body portion can be admitted therethrough.
  • 23. The fastening tool of claim 20, wherein the body portion includes a first body portion and a second body portion, the first body portion being coupled at opposite ends to the head portion and the second body portion, the second body portion being sized relatively smaller than the first body portion and wherein an intersection between the slotted portion and the first portion is sized smaller than the first body portion such that only the second body portion can be admitted therethrough.
  • 24. The fastening tool of claim 23, wherein the head of the clamp pin is frusto-conical in shape and configured to matingly engage a conical detent formed into a surface of the coupling bracket.
  • 25. The fastening tool of claim 20, wherein the slotted portion defines a protrusion proximate the first portion, the protrusion forming a dogleg in the slotted coupling aperture which prevents the clamp pin from being pushed from the second portion to the first portion in a generally straight line.
PRIORITY & CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 10/072,603 entitled Magazine Assembly for Fastening Tool, now U.S. Pat. No. 6,609,646, filed Feb. 7, 2002 which claimed the benefit of U.S. Provisional Application No. 60/267,359, filed Feb. 8, 2001. Other features of the present invention are discussed and claimed in commonly assigned copending U.S. application Ser. No. 10/10,072,668 entitled Pneumatic Fastening Tool.

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Provisional Applications (1)
Number Date Country
60/267359 Feb 2001 US
Continuation in Parts (1)
Number Date Country
Parent 10/072603 Feb 2002 US
Child 10/134784 US