Keyless clamp assembly for reciprocating tool

Information

  • Patent Grant
  • 6237231
  • Patent Number
    6,237,231
  • Date Filed
    Tuesday, October 10, 1995
    29 years ago
  • Date Issued
    Tuesday, May 29, 2001
    23 years ago
Abstract
A clamp for the blade of a hand held reciprocating tool includes a spindle coupled to the drive mechanism. A slot is formed in the spindle for receiving the blade tang and a collar is threadably received on the spindle. A blade clamping member is disposed between the collar and the blade and includes an engaging member for engaging a hole in the blade tang and a pair of ears which engage the upper and lower shoulders of the blade tang to provide three points of engagement when the collar is tightened. The clamp also includes a nose section which engages the blade at its junction with the tang to provide reinforcement against breakage.
Description




BACKGROUND OF THE INVENTION




Hand held reciprocating tools, such as electric reciprocating saws, include removable blades which permit the use of different cutting edges as may be necessary for cutting different materials and for the replacement of worn or damaged blades. This requires a blade mounting system which allows rapid blade replacement while accurately and firmly coupling the blade to the tool. One problem with blades for hand held reciprocating saws is breakage at the junction between the blade and the substantially narrower tang.




SUMMARY OF THE INVENTION




It is an object of the invention to provide a new and improved blade clamping assembly for reciprocating tools.




A further object of the invention is to provide a blade clamping assembly for reciprocating saws which does not require the use of a key or tool for blade replacement.




Another object of the invention is to provide a keyless blade clamping assembly for reciprocating saws which permits rapid blade replacement and firmly and accurately holds the blade in position.




A still further object of the invention is to provide a blade clamping assembly for reciprocating saws which reduces blade breakage.




These and other objects and advantages of the present invention will become more apparent from the detailed description thereof taken with the accompanying drawings.




In general terms the invention comprises a reciprocating tool including a reciprocating member and clamping means for clamping one end of a blade to the reciprocating member, the blade having a hole formed in the one end. The clamping means includes a first member for engaging the blade at spaced apart points and a second member coupled to the first member for engaging the hole and so as to provide three points of contact between the clamping means and the blade. Means are also provided for engaging the clamping means and the reciprocating means for adjustably forcing the first and second members into pressure engagement with the end of the blade.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

shows a tool in which the invention may be used;





FIG. 2

is an exploded perspective view of the preferred embodiment of the invention;





FIG. 3

is a perspective view of a portion of the embodiment of

FIG. 2

;





FIG. 4

is a cross-sectional view of the embodiment of

FIG. 2

;





FIG. 5

is a view taken along lines


5





5


of

FIG. 4

;





FIG. 6

is a view taken along lines


6





6


of

FIG. 5

;





FIG. 7

is a cross-sectional view of a first alternate embodiment of the invention;





FIG. 8

is a view taken along lines


8





8


of

FIG. 7

;





FIG. 9

is a cross-sectional view of a second alternate embodiment of the invention;





FIG. 10

is a cross-sectional view of a third alternate embodiment of the invention; and





FIGS. 9 and 10

illustrate a second alternate embodiment of the invention.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS





FIG. 1

shows a hand held reciprocating tool, such as a saw


10


, having an axially reciprocating spindle


12


which is coupled to the saw blade


14


by a clamping assembly


16


.




The clamping assembly


16


according to the preferred embodiment of the invention is shown in

FIGS. 2-5

to include a metallic clamping member


18


for securing the blade


14


to the spindle


12


and a sleeve


20


threadably received on the spindle


12


for forcing the clamping member


18


against the blade


14


and the spindle


12


thereby securing the blade


14


to the spindle. The spindle


12


, the clamping member


18


and the sleeve


20


reciprocate within a guide mounted on the tool


10


.




The spindle


12


is an elongate shaft member having one end


22


constructed and arranged for being secured to the operating mechanism of the saw


10


whereby the spindle is moved axially when the saw


10


is energized. The opposite end


23


of the spindle has external threads


24


and an axially extending slot


26


for receiving the tang


28


of the blade


14


. The slot


26


is offset relative to the axis of spindle


12


and divides the end


23


into left and right portions


32


and


34


. An inclined surface


36


is formed in the forward portion


32


of spindle


12


and intersects the slot


26


intermediate its ends and extends outwardly therefrom. The opposite side of the slot


26


is defined by a generally planar surface


37


.




The clamping member


18


has a forward nose portion


38


and a rear wedge portion


40


. The surface


41


of member


18


is generally planar while the opposite surface (

FIG. 3

) of the nose portion


38


includes a section of a frusto cone


42


and a short cylindrical section


44


. At the sides of the surface


41


and adjacent the junction of the sections


42


and


44


, there are a pair of extending ears


45


and


46


.




The wedge portion


40


includes a surface


48


which is inclined relative to the planar surface


41


at the same angle that the surface


36


in spindle


12


is inclined relative to the axis of the slot


26


. Inwardly of the inclined slot there is an axially extending surface


50


, and a laterally extending flange


52


disposed between the nose portion


38


and the wedge portion


40


. In the embodiment of the invention shown in

FIGS. 2-6

, a recess


54


is formed in the wedge portion


40


for housing a metallic ball or engaging member


56


which is suitably fixed within recess


54


so that only a portion extends from the surface


41


(FIG.


4


), that extending portion of the ball functioning to engage a hole in the saw blade as will be described. The opposite portion of the ball


56


(as seen in

FIG. 4

) is ground to conform to the contours of the surfaces


48


and


54


. Instead of a ball


56


, a section of a sphere could also be formed on surface


41


and project therefrom in the same manner as ball


56


. In other embodiments of the invention the ball


56


could be replaced by a member having a conical projection for engaging the hole in the saw blade, or the ball


56


could be replaced by a pin or projection having other configurations.




The sleeve


20


is a generally tubular member having internal threads


60


which are complementary to the threads


24


formed on the end


23


of the spindle


12


. The threads


60


extend from a first end of sleeve


20


to a point short of the opposite end which has an inwardly extending rim


62


formed thereon. A plurality of radially extending fins


64


project radially outwardly from the sleeve


20


adjacent the first end.




The blade


14


is conventional and includes a tang


28


which has a reduced width with respect to the blade itself. Conventional blades of the type illustrated have a hole


66


formed in the tang


28


for being secured by a set screw. At the junction between the blade


14


and the tang


28


there may be upper and lower shoulders


68


and


69


, respectively, or only a singled lower shoulder


69


may be present.




As best shown in

FIG. 5

, the ears


45


and


46


on clamping member


18


are spaced apart from each other and from the ball


56


such that the ears


45


and


46


engage the upper and lower shoulders


68


and


69


. The surface of the engaging member


56


engages the rearward edge of the hole


66


in the tang of the saw blade. In the case where the tang


28


only has a single shoulder


69


, the ear


45


engages the upper edge of the tang


28


.




The clamping member


18


is disposed adjacent the slot


26


with its inclined surface


48


facing the inclined surface


36


. In addition, the sleeve


20


is threaded onto the spindle


12


with the rim


62


surrounding the cylindrical section


44


of member


18


and engaging the flange


52


. When the tang


28


of blade


14


is inserted into the slot


26


, it moves between the surfaces


37


of spindle


12


and


41


of clamping member


18


until the shoulder


68


and


69


engage the ears


45


and


46


. At this point, the engaging member


56


engages the rearward rim of hole


66


. The sleeve


20


may then be tightened to force the clamping member


18


into the slot


26


and to force the surface


48


of clamping member


18


against the surface


36


of spindle


12


. This forces the engaging member


56


against the back of hole


66


so that the blade


14


is urged inwardly toward the saw


10


and the shoulders


68


and


69


are forced against the ears


45


and


46


to provide a rigid three point support for the blade


14


. In addition, the nose portion


42


of the clamping member extends past the inner end of tang


28


and onto the blade


14


to prevent the blade from flexing at the intersection with tang


28


thereby reducing the possibility of blade failure at what is otherwise its weakest point. The ears


45


and


46


and the engaging member


56


are also arranged such that the blade


14


tilts downwardly at a slight angle of approximately 3° as seen in

FIG. 1

to facilitate cutting. The guide


21


is preferably a tubular member having longitudinal slots


70


on its inner surface


71


for receiving the fins


64


. This facilitates the tightening of the sleeve


20


and protects the operator from the reciprocating fins


64


.





FIGS. 7 and 8

illustrate an alternate embodiment of the invention which includes a spindle


12




a


, a collar


20




a


, and a sleeve


76


disposed therebetween. The spindle


12




a


has an unthreaded end


77


, external threads


24




a


adjacent the unthreaded end


77


and an axial slot


26




a


which extends through the unthreaded end portion. The sleeve


76


surrounds the unthreaded end


77


of spindle


12




a


and the slot


26




a


. The collar


20




a


has internal threads


60




a


at one end which are complementary to the threads


24




a


of the spindle


12




a


. The remaining portion of the inner surface


78


of collar


20




a


is unthreaded and surrounds the outer surface


80


of sleeve


76


. Aligned holes


82


and


84


are formed in this sleeve


76


and the spindle


12




a


, respectively, for receiving an engaging member or detent


56




a


having engaging surfaces


86


and


88


at its ends, respectively. The collar


20




a


has an outwardly facing, frusto conical internal surface


90


at its end opposite the threads


60




a


and which engages the outer spherical surface


86


of engaging member


56




a


. The engaging member


56




a


is positioned such that when a blade


14




a


is in the slot


26




a


, the hole


66




a


in the blade tang


28




a


is adjacent the engaging member


56




a


. Upon tightening, the collar


20




a


moves to the right as viewed in

FIG. 7

thereby forcing the end


88


of engaging member


56




a


against the rearward rim of the hole


66




a


in blade tang


28




a


. The hole


66




a


is offset relative to engaging member


56




a


so that the rear edge of the hole


66




a


is engaged by the engaging member


56




a


. This forces the blade


14




a


toward the saw


10


thereby forcing the shoulders


68




a


and


69




a


into engagement with the outer edge


92


of the sleeve


76


to provide a firm three point support. The edge


92


is preferably arcuate for engagement with the complementary surface of the shoulders


68




a


and


69




a.






A second detent


93


may be disposed in a counter sunk hole


94


formed in spindle


12




a


in alignment with the hole


84


. A spring


95


urges the detent


93


into the hole


66


on the side of tang


28


opposite the engaging member


56




a.







FIGS. 9 and 10

show another alternate embodiment of the invention including a clamp member


100


constructed and arranged to be employed with a sawblade


101


having a modified tang


102


. In particular, the tang


102


includes relatively smaller tangs


103


and


104


extending laterally from its opposite sides. Each tang


103


and


104


has forward and rear arcuate edges


108


and


109


, respectively, with the edges


108


and


109


converging toward the projecting ends of the tangs


103


and


104


. In addition, a hole


110


, is formed in the tang


102


rearwardly of the tangs


103


and


104


.




The clamping member


100


is similar to that shown in

FIGS. 2-6

and includes a rear wedge portion


112


having an inclined surface


114


and a front nose portion


115


. The surface


116


of the clamping member


100


on the side opposite the inclined surface


114


is generally planer for engaging the tang


102


. A pair of spaced apart ears


120


and


122


extend from the surface


116


and intermediate the ends of the nose portion


116


and are intended to be positioned on opposite sides of the tang


103


. A second pair of ears


124


and


126


project from the surface


116


and are intended to be positioned on opposite sides of the tang


104


. In addition, an engaging member


118


having the shape of a truncated cone extends outwardly from the surface


116


opposite the wedge portion


112


and is intended to be housed in the hole


110


. Each of the ears


120


and


122


and


124


and


126


has an arcuate surface


123


which is complementary with the opposed surface of the tangs


103


and


104


. In addition, the ears


122


and


126


and the engaging member


118


are spaced from each other such that when the conical surface of the engaging member


118


engages the rearward edge of the hole


110


, the surfaces


123


of ears


122


and


126


engage the edges of the tangs


102


and


103


.




The spindle


130


and the sleeve


132


are similar to the corresponding parts of the embodiment of

FIGS. 1-5

. When the tang


102


of blade


101


is inserted into the slot


134


formed in spindle


130


, and between the clamping member


100


and the surface


134


of spindle


130


so that the hole


110


is moved into a position opposite the engaging member


118


, the tangs


103


and


104


are positioned between the ears


120


and


122


and


124


and


126


respectively with the surfaces


123


opposed to the tangs


103


and


104


. The sleeve


132


may then be tightened to force the inclined surface


114


on the clamping member


100


against the complementary inclined surface


136


on the spindle


130


. This forces the engaging member


118


against the rear edge of the hole


110


and the surfaces


123


on ears


122


and


126


into engagement with the tangs


103


and


104


. As a result, the blade is urged inwardly of the spindle


130


and firmly locked in position.




While only a few embodiments of the invention have been illustrated and described, it is not intended to be limited thereby but only by the scope of the appended claims.



Claims
  • 1. A reciprocating saw comprising:a reciprocatable spindle; a saw blade; a clamping assembly for interconnecting said saw blade with said spindle, said clamping assembly including: a first member interconnected with said spindle and engagable with a first portion of said saw blade to limit movement of said saw blade in a first direction relative to said spindle; and a second member movably mounted relative to said spindle and being engagable with a second portion of said saw blade spaced from said first portion, said second member being movable relative to said spindle from a first position to a second position where said saw blade is held under tension between said first and second members.
  • 2. A reciprocating saw as claimed in claim 1, wherein a longitudinal direction is generally defined by reciprocating motion of said spindle, and wherein tension in said saw blade is substantially parallel to the longitudinal direction.
  • 3. A reciprocating saw as claimed in claim 1, wherein said saw blade includes teeth that define a cutting plane, and wherein movement of said second member from the first position to the second position occurs along a path that is transverse the cutting plane.
  • 4. A reciprocating saw as claimed in claim 3, wherein the path is substantially perpendicular to the cutting plane.
  • 5. A reciprocating saw as claimed in claim 1, wherein said second member includes an engaging surface engagable with said saw blade, said engaging surface being spherical in shape.
  • 6. A reciprocating saw as claimed in claim 1, wherein said second member is positionable at least partially within a hole in said saw blade.
  • 7. A reciprocating saw as claimed in claim 6, wherein said first member includes two ears engagable with two shoulders on said saw blade.
  • 8. A reciprocating saw as claimed in claim 1, wherein movement of said second member from the first position to the second position causes said first portion of said saw blade to be pulled tight against said first member.
  • 9. A reciprocating saw comprising:a reciprocatable spindle that reciprocates in a longitudinal direction; a saw blade having teeth that define a cutting plane; a clamping assembly for interconnecting said saw blade with said spindle, said clamping assembly including: a first member interconnected with said spindle and engagable with a first portion of said saw blade to limit movement of said saw blade in a first direction relative to said spindle; and a second member movably mounted relative to said spindle and being engagable with a second portion of said saw blade spaced from said first portion, said second member being movable relative to said spindle from a first position to a second position where said saw blade is held under pressure engagement between said first and second members, wherein movement of said second member from said first position to said second position occurs along a path that is transverse to the cutting plane, and wherein the pressure engagement in said saw blade is substantially parallel to the longitudinal direction; wherein said saw blade is held under tension between said first and second members.
  • 10. A reciprocating saw comprising:a reciprocatable spindle that reciprocates in a longitudinal direction; a saw blade having teeth that define a cutting plane; a clamping assembly for interconnecting said saw blade with said spindle, said clamping assembly including: a first member interconnected with said spindle and engagable with a first portion of said saw blade to limit movement of said saw blade in a first direction relative to said spindle; and a second member movably mounted relative to said spindle and being engagable with a second portion of said saw blade spaced from said first portion, said second member being movable relative to said spindle from a first position to a second position where said saw blade is held under pressure engagement between said first and second members, wherein movement of said second member from said first position to said second position occurs along a path that is transverse to the cutting plane, and wherein the pressure engagement in said saw blade is substantially parallel to the longitudinal direction; wherein said first member includes two ears engagable with two shoulders on said saw blade.
  • 11. A reciprocating saw comprising:a reciprocatable spindle that reciprocates in a longitudinal direction; a saw blade having teeth that define a cutting plane; a clamping assembly for interconnecting said saw blade with said spindle, said clamping assembly including: a first member interconnected with said spindle and engagable with a first portion of said saw blade to limit movement of said saw blade in a first direction relative to said spindle; and a second member movably mounted relative to said spindle and being engagable with a second portion of said saw blade spaced from said first portion, said second member being movable relative to said spindle from a first position to a second position where said saw blade is held under pressure engagement between said first and second members, wherein movement of said second member from said first position to said second position occurs along a path that is transverse to the cutting plane, and wherein the pressure engagement in said saw blade is substantially parallel to the longitudinal direction; wherein movement of said second member from the first position to the second position causes said first portion of said saw blade to be pulled tight against said first member.
Parent Case Info

This is a continuation-in-part of application Ser. No. 08/345,997, filed Nov. 29, 1994, entitled “KEYLESS CLAMP ASSEMBLY FOR RECIPROCATING TOOL”, now abandoned.

US Referenced Citations (47)
Number Name Date Kind
2049898 Driest Aug 1936
2565344 Benham Aug 1951
3114402 Jacoff Dec 1963
3259158 Garamy Jul 1966
3338278 Reuterfors Aug 1967
3521686 Weinmann Jul 1970
3583716 Daniel Jun 1971
3750283 Hoffman Aug 1973
3802079 Ketchpel, Jr. et al. Apr 1974
3823473 Hoffman Jul 1974
3927893 Dillon et al. Dec 1975
3964163 Russo Jun 1976
4011657 Vance Mar 1977
4020555 Hedrick May 1977
4083112 Palm Apr 1978
4106181 Mattchen Aug 1978
4204692 Hoffman May 1980
4285129 Hoffman Aug 1981
4294013 Krieg Oct 1981
4299402 Hoffman Nov 1981
4351112 Nalley Sep 1982
4441255 Hoffman Apr 1984
4470196 Hoffman Sep 1984
4528753 Kuhlmann et al. Jul 1985
4550500 Kuhlmann et al. Nov 1985
4594781 Hoffman Jun 1986
4601477 Barrett et al. Jul 1986
4648182 Hoffman Mar 1987
4739557 Wagner Apr 1988
4941246 Finnegan Jul 1990
5058280 Pollak et al. Oct 1991
5103565 Holzer, Jr. Apr 1992
5165173 Miller Nov 1992
5233892 Roberts Aug 1993
5272948 Theising Dec 1993
5322302 Quirijnen Jun 1994
5324052 Ortmann Jun 1994
5340129 Wright Aug 1994
5351590 Everts et al. Oct 1994
5363733 Baird et al. Nov 1994
5402580 Seto et al. Apr 1995
5421232 Laverick Jun 1995
5433457 Wright Jul 1995
5439472 Evans et al. Aug 1995
5443276 Nasser et al. Aug 1995
5458346 Briggs Oct 1995
5487221 Oda et al. Jan 1996
Foreign Referenced Citations (5)
Number Date Country
1484393 Sep 1977 GB
1597240 Sep 1981 GB
2173734 Oct 1986 GB
WO 8908524 Sep 1989 WO
9527583 Oct 1995 WO
Continuation in Parts (1)
Number Date Country
Parent 08/345997 Nov 1994 US
Child 08/541894 US