Lockable telescoping screwdriver

Description

SCOPE OF THE INVENTION

This invention relates generally to a screwdriver for driving collated screws which are joined together in a strip, and, more particularly, to a power screwdriver with a slide body which extends and retracts in driving collated screws and which can be maintained in a retracted position.

BACKGROUND OF THE INVENTION

Collated screwstrips are known in which the screws are connected to each other by a holding strip of plastic material. Such strips are taught, for example, by U.S. Pat. No. 4,167,229 issued Sep. 11, 1979 and its related Canadian Patents 1,040,600 and 1,054,982 as well as U.S. Pat. No. 4,930,630, the disclosures of which are incorporated herein by reference. Screws carried in such screwstrips are adapted to be successively incrementally advanced to a position in alignment with and to be engaged by a bit of a reciprocating, rotating power screwdriver and screwed into a workpiece. In the course of the bit engaging the screws and driving it into a workpiece, the screw becomes detached from the plastic holding strip leaving the strip as a continuous length.

In the use of such collated screwstrips in screwdrivers, the strip serves a function of assisting in guiding the screw into a workpiece and, to accomplish this, the holding strip is retained against movement towards the workpiece. In the screwstrip, each screw to be driven has its threaded shaft threadably engaged in a threaded sleeve of the holding strip such that on the screwdriver engaging and rotating each successive screw, the screw turns within the sleeve which acts to guide the screw as it moves forwardly into threaded engagement into the workpiece. Preferably, only after the tip of the screw becomes engaged in the workpiece, does the head of the screw come into contact with the sleeves. Further, forward movement of the screw into the workpiece then draws the head downwardly to engage the sleeve and to rupture the sleeve by reason of the forward movement of the head with the strip retained against movement towards the workpiece. The sleeve preferably is configured to have fragile straps which break on the head passing through the sleeve such that the holding strip remains intact as a continuous length. Since the holding strip is a continuous length, on advancing the screwstrip with each successive screw to be driven, it necessarily results that portion of the holding strip from which each screw has been driven are also advanced to exit from the power screwdriver.

Known power screwdrivers for driving such collated screwstrips include U.S. Pat. No. 4,146,071 to Mueller et al, issued Mar. 27, 1976, and U.S. Pat. No. 5,186,085 to Monacelli, issued Feb. 16, 1993, the disclosure of which are incorporated herein by reference. Such known power screwdrivers include a rotatable and reciprocally moving screwdriver shaft which is turned in rotation by an electric motor. A screwdriving bit forms a forwardmost portion of the shaft for engaging the head of each successive screw as each screw is moved into a driving position, axially aligned under the screwdriver shaft.

Known power screwdrivers for collated screwstrips suffer the disadvantage appreciated by the applicant that they are dedicated to drive collated screws. In use, they cannot be used to drive separate screws or to withdraw misdriven screws or other screws which are desired to be removed. Known power screwdrivers for collated screwstrips also suffer the disadvantage that it is difficult to engage and change bits mounted to the front end of the drive shaft.

SUMMARY OF THE INVENTION

To at least partially overcome these disadvantages of previously known screwdrivers, the present invention provides a power screwdriver for collated screwstrips which may be latched or locked in a retracted position for use as a normal power screwdriver so as to drive separate screws and/or to withdraw screws and the like independently of the collated screwstrip.

An object of the present invention is to provide a power screwdriver adapted for driving collated screws which may be latched in an extension limiting position in which the screwdriver may be used independently of the collated screwstrip.

Another object is to provide a screwdriver for collated screws which permits latching in a position for use as a screwdriver with or without the collated screwstrip engaged in the screwdriver assembly.

Another object is to provide a screwdriver for collated screwstrips which may be latched in a position permitting access to the drive shaft and/or bit for facilitating removal and/or changing of the bit and/or to permit manual engagement with the bit of screws separate from the collated screwstrip.

Accordingly, the present invention provides a power screwdriver attachment for driving collated screws having a housing and a slide body movable between extended and retracted positions to drive screws from a collated screwstrip, a latching system to releaseably latch the slide body in an extension limiting position in which the power driver is able to be used as a power screwdriver independent of the collated screwstrip. The screwdriver attachment may be used as a power screwdriver for driving or withdrawing screws whether or not a screwstrip is engaged in the attachment. When latched, the screwdriver attachment permits the collated screwstrip to be withdrawn or inserted and, as well, permits the drive shaft to be rotated either forwardly or rearwardly. The screwdriver attachment preferably has a depth adjustment mechanism to adjust the extent to which any screw is driven into a workpiece and which mechanism remains operative when the attachment is latched in the extension limiting position. In the extension limiting position, a bit carried on a forward end of a driver shaft is preferably accessible for manual engagement of separate screws thereon to permit driving or removal of such separate screws with the power screwdriver attachment. The latching system preferably is readily manually accessible to a person using the power tool.

The construction of the screwdriver is preferably compact and lightweight. A compact design may be achieved by camming portions of the slide body extending within the housing rearwardly past the coupling of the housing to the power driver. A lightweight design utilizes lightweight synthetic plastic and nylon materials to comprise major portions of the element.

In one aspect, the present invention provides an apparatus for driving with a power driver a screwstrip comprising threaded fasteners such as screws or the like, which are joined together in a strip comprising:

a housing;

an elongate drive shaft for operative connection to a power driver for rotation thereby and defining a longitudinal axis;

a slide body coupled to the housing for displacement parallel to the axis of the drive shaft between an extended position and a retracted position;

a spring biasing said slide body forwardly relative to the housing parallel to the axis to the extended position;

screw feed advance mechanism to engage the screwstrip and successively, incrementally advance screws on the screwstrip to be axially in alignment with said drive shaft for driving of the screws by the drive shaft, and

the screw feed advance mechanism coupled between the slide body and the housing whereby displacement of the slide body relative the housing between the extended position and the retracted position activates the screw feed advance mechanism to advance successive screws;

an extension limit mechanism activatable to releasably prevent the housing and slide body from being extended relative each other towards the extended position beyond an extension limit position. The extension limit mechanism may, in one aspect, lock the housing and slide body together against relative movement. Preferably, the slide body has a guide channel mechanism for said screwstrip extending through the slide body,

a guide mechanism to locate successive of the screws advanced via the guide channel to be axially in alignment with said drive shaft for engagement in driving of the screws from the guide mechanism by the drive shaft, and

screw feed advance mechanism to engage the screwstrip and successively, incrementally advance screws on the screwstrip through the guide channel mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects and advantages of the present invention will appear from the following description taken together with the accompanying drawings, in which:

FIG. 1

is a pictorial view of a power screwdriver in accordance with a first embodiment of the present invention;

FIG. 2

is an exploded pictorial view of the housing and slide body shown in

FIG. 1

;

FIG. 3

is a pictorial view of the opposite side of the slide body to that shown in

FIG. 2

but with a screwstrip positioned therein;

FIG. 4

is a schematic partially cross-sectional view of the driver attachment of

FIG. 1

in a fully extended position as seen in

FIG. 1 through a

plane passing through the longitudinal axis of the drive shaft and centrally of the screws in the screwstrip;

FIG. 5

is a view identical to

FIG. 4

but with the driver attachment in a partially retracted position in driving a screw into a workpiece;

FIG. 6

is an end view of the nose portion of

FIG. 2

;

FIG. 7

is a view identical to

FIG. 4

but with the driver attachment in a more retracted, extension limit position;

FIG. 8

is a schematic cross-sectional view of the driver attachment of

FIG. 7

along lines

8

—

8

′ and with the nose portion removed;

FIGS. 9

,

10

and

11

are respectively, side, top and front views of the latch member shown in

FIG. 8

;

FIG. 12

is an enlarged cross-sectional view of the housing alone as seen along line

8

—

8

′ of

FIG. 7

in the absence of the other components;

FIG. 13

is an enlarged side view of the righthand side of

FIG. 8

, however, showing the housing alone;

FIG. 14

is a schematic pictorial view of another version of a removable nose portion with a segment of a screwstrip;

FIG. 15

is a partially cut-away pictorial view of the nose portion of

FIG. 14

from a different perspective;

FIG. 16

is an exploded pictorial view of a housing and slide body in accordance with another aspect of the invention, however, substantially the same in most respects to the embodiment shown in

FIG. 2

;

FIG. 17

is a pictorial view of the opposite side of the slide body to that shown in FIG.

16

and with a screwstrip positioned therein in a manner similar to that shown in

FIG. 3

;

FIG. 18

is a schematic partially cross-sectional view of the driver attachment of

FIG. 16

in a fully retracted position similar to that shown in FIG.

7

and in a locked position;

FIG. 19

is a schematic pictorial exploded view of the lock mechanism shown in

FIG. 18

; and

FIG. 20

is a partial view of the embodiment of

FIG. 16

in a fully retracted position identical to that in

FIG. 18

except showing the locking mechanism in an unlocked position.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is made to

FIG. 1

which shows a complete power screwdriver assembly

10

in accordance with the present invention. The assembly

10

comprises a power driver

11

to which a driver attachment

12

is secured. The driver attachment

12

engages a collated screwstrip

14

with spaced screws

16

to be successively driven.

Reference is made to

FIG. 2

showing an exploded view of major components of the driver attachment

12

as housing

18

and a slide body comprising a rear portion

22

and a removable nose portion

24

.

FIGS. 4 and 5

show in cross-section the interaction of these components.

As seen in

FIG. 4

, the rearmost end

26

of the housing

18

has a rearwardly directed socket

27

with a longitudinal slot

28

in its side wall to receive and securely clamp the housing

18

onto the housing

30

of the power driver

11

so as to secure the housing

18

of the driver attachment to the housing

30

of the power driver against relative movement. The power driver

11

has a chuck

32

rotatable in the driver housing

30

by an electric motor (not shown). The chuck

32

releasably engages the driver shaft

34

in known manner. The housing

18

is provided with an optional lateral flange

36

at its rear end to which a known screwstrip containing cartridge (not shown) may be secured in a conventional manner if a screwstrip in the form of a coil is desired to be utilized. It is preferred, however, to utilize screwstrips as shown in the form of discrete, self-supporting strips which are preferably straight.

As seen in

FIG. 4

, the slide body

20

is slidably received in the housing

18

with the driver shaft

34

received in a bore passing through the rear portion

22

and nose portion

24

of the slide body

20

. A compression spring

38

disposed between the housing

18

and the rear portion

22

coaxially about the driver shaft

34

biases the slide body away from the housing

18

from a retracted position towards an extended position. As shown, the spring

38

is disposed between the housing

18

and the rear portion

22

. Slide stops

25

, best shown in

FIG. 2

, are secured to the rear portion

22

of the slide body. Two slide stops

25

slide in two longitudinal slots

40

on each side of the part cylindrical side wall

42

of the housing

18

to key the rear portion

22

of the slide body to the housing

18

against relative rotation and to prevent the slide body being moved out of the housing

18

. The slide stops

25

are slidable in the longitudinal slots

40

and engage either end of the slots

40

to limit relative sliding of the slide body

20

and housing

18

between a fully retracted position and a fully extended position.

As will be described in greater detail, the slide body

20

is adapted to receive a collated screwstrip

14

, to successively advance the screwstrip

14

, and to position and drive successive screws from the screwstrip in a cycle of extension and retraction of the slide body

20

relative the housing

18

.

Reference is made to

FIGS. 1

,

2

and

8

to

13

which show a latching system adapted to latch the slide body

20

relative the housing

18

against extension towards the extended position past an extension limit position. The latching system comprises a latch member

402

mounted between two support flanges

406

and

408

preferably integrally formed with the housing

16

. Latch member

402

is adapted to releasably couple with a catch member

410

formed on one of the slide stops

25

.

Support flanges

406

and

408

extend generally, radially outwardly and axially along housing

18

on either side of the slot

40

so as to define an axially and radially extending slot

412

therebetween opening radially inwardly into slot

40

.

Latch member

402

is pivotally mounted within the slot

412

by pivot pin

414

which extends between the flanges

406

and

408

through apertures in each of the flanges and through an aperture

416

in the latch member

402

. Latch member

402

is pivotable between an activated position shown in solid lines in FIG.

8

and an inactivated position shown in dashed lines in FIG.

8

. The latch member

402

carries two semi-circular bosses

418

and

420

, one on each side thereof. Each flange

406

and

408

has two spaced circular openings

422

and

424

each sized to receive a respective one of the bosses

418

and

420

. On each side, a boss

418

or

420

is to either locate in an opening

424

to retain the latch member

402

in the activated position or in an opening

422

to retain the latch member

402

in the inactivated position. The bosses

418

and

420

and the openings

422

and

424

cooperate to limit movement between the activated and inactivated positions and to bias the bosses to assume the closest of the two positions, preferably due to the inherent resiliency of the flanges. The area between the opening

422

and

424

preferably is, at least partially, cut-away.

Latch member

402

has an engagement portion

426

which extends radially beyond the flanges

406

and

408

for engagement manually by a user to move the latch member

402

between the activated position and the inactivated position.

The latch member

402

has a forwardly extending resilient arm

428

carrying a rearwardly directed hook

430

. One of the stop slides

25

is shown to have a catch member

410

formed as a rib-like protrusion which extends radially into the slot

412

between the flange members

406

and

408

to be axially slidable therein upon reciprocal, relative sliding of the slide body

20

and the housing

18

. Catch member

410

has a tapering rearwardly directed cam surface

432

and a forwardly directed catch shoulder

434

as best seen in FIG.

2

.

FIG. 8

shows the slide body

20

and the housing

18

in an extension limit position in which with the latch member

402

is in an activated position and its hook

430

is engaged on catch shoulder

434

of the catch member

410

to prevent the relative extension of the slide body relative the housing, that is, towards the extended position. From positions in which the slide body

20

is extended forward of the housing relative the extension limit position, the latched condition shown in

FIG. 8

may be attained by placing the latch member

402

in the activated position and then retracting the slide body

20

relative the housing

18

past the extension limit position. On rearward movement of the slide body

20

, with respect to the housing

18

a forward cam surface

436

of the hook

430

engages the rear cam surface

432

of the catch member

410

and the flexible arm

428

deflects radially outwardly to pass over the catch member

410

and subsequently snap into engagement forward of the catch shoulder

434

with a surface

438

of the hook

430

to engage catch shoulder

434

and to prevent forward extension of the slide body. The forces required to flex arm

428

are less than that required to shift the latch member

402

from the activated to the inactivated position.

To release the hook

430

from catch member

410

, due to the flexibility of the arm

428

, a user must first apply pressure to retract the slide member

20

rearwardly relative of the housing. With the slide member retracted rearwardly from the extension limit position, the catch member

410

may then be moved by manual application of forces onto the engagement portion

426

to place the latch member

402

in the inactivated position.

When the latch member is in the inactivated position, the hook member

430

and the catch member

410

do not engage each other and, thus, do not impede extension or retraction of the slide body

20

relative the housing

18

.

Reference is made to

FIG. 7

which shows the screwdriver attachment in the extension limit position. In this position, the drive shaft

34

is free to be rotated by the power driver. As to be described in greater detail, an adjustable depth stop mechanism remains operative. The depth stop mechanism comprises an elongate rod

110

which is axially slidable relative the side wall of the housing

18

parallel the longitudinal axis of the drive shaft. A depth setting cam member

114

may be positioned to set the extent to which the rod

110

may slide rearwardly such that the front end

118

of the rod

110

may be engaged by an annular stop surface

119

provided on the nose portion

24

of the slide body and thereby prevent the slide body

20

from retracting relative the housing

18

beyond an adjustable retraction limit position. With the depth stop mechanism remaining operative, the extent to which the slide body

20

may retract may be set to provide a desired retraction limit position at the retracted position or at a distance therefrom towards the extended position.

In the extension limit position shown in

FIGS. 7 and 8

, the latched driver attachment can be used as a screwdriver independently of the collated screwstrip and with or without the collated screwstrip maintained in engagement within the slide body. As seen in

FIG. 7

, in the extension limit position, the bit

122

carried on the front end of the driver shaft

34

is proximate the forward end of the nose portion. A separate screw may manually be placed by a user wish the head of the screw in engagement with the bit

122

and the bit may then be driven by rotating the drive shaft

34

with the power driver

11

is in the manner with a normal screwgun. In that the depth stop mechanism remains operational, the depth stop mechanism can be used to set the depth to which this separate screw is driven. For example, the slide body

20

is capable of retraction from the extension limit position to the retraction limit position, if they are different, while the latch member remains activated.

The drive shaft

34

extends past the spent screwstrip

13

′ and is free to rotate with the screwstrip left in place as may, for example, be desired to drive and/or to remove but a few screws. Alternately, the screwstrip

13

may be manually withdrawn while the attachment is latched in the extension limit position. By way of example, in use in driving collated 1¼ inch (3.2 cm) drywall screws for securing drywall, circumstances may arise where one or more different screws, for example, of 1¾ inch (4.5 cm) length may be desired to be used. With the latching system, a user need only secure the attachment into a latched configuration in order for the user to then drive one or more longer screws by manually engaging each of the screws to be driven onto the end of the bit. Similarly, while using the attachment as to delve screws from a screwstrip, it is desired that a screw be withdrawn, the attachment may be latched in the extension limit position, the bit positioned over the screw to be withdrawn and the direction of rotation of the power driver reversed to withdraw the screw.

Latching of the attachment in the extension limit position may also be advantageous for removal of a removable bit

122

from he drive shaft

34

. With the attachment in the extension limit position and with the screwstrip removed, the bit is accessible not only axially from the front end of the nose portion

24

but also radially via the radially extending screw access opening

86

which aligns with and is received within the radially extending opening in the housing

18

into which the screw feed channel element

76

is axially slidable. Thus, with the attachment latched in the extension limit position, the bit

122

and/or the driver shaft

34

are accessible for changing of the bit.

FIG. 8

schematically shows the bit

122

as removably secured to the driver shaft

34

against rotation by a rearward extension

439

of the bit extending into a forwardly opening axial socket

441

in the driver shaft with a split ring retaining the bit in the socket such that the bit can be removed by applying axially directed forward forces on the bit. A slot

440

extends radially into the driver shaft rearward of the bit and opening into the socket

441

such that a lever tool

444

as illustrated in broken lines in

FIG. 7

may have its end inserted radially into the slot

440

to be used to apply forwardly directed surfaces to the rear of the bit

122

to remove the bit from the driver shaft. Such an assembly for a socket to receive the bit and a lever tool for removal of the bit are described in the applicant's International Application PCT/CA94/00209, published Oct. 27, 1994 the disclosure of which is incorporated herein by reference. With the driver attachment locked in the extension limit position as shown in

FIGS. 7 and 8

, the slot

440

is readily accessible for insertion of the tool

444

radially through both the housing and through the opening

86

in the nose portion. As may be seen, the housing and the nose portion both have radially directed slots in the same side which are complementary in the sense that when the housing and slide body are proximate the retracted position, they provide radial access to the driver shaft as is particularly useful for ingress and exit of the lever tool. With the driver shaft free to rotate, the slot

440

can be disposed to open into the opening

86

for engagement by the lever tool. Preferably, the screwstrip would be totally or partially removed from the nose portion before using the lever tool

444

.

Only one arrangement has been illustrated for relative latching of the housing

18

and the slide body

20

. It is to be appreciated that many different latching arrangements can be provided to couple the housing and the slide body against extension past an extension limit position. Such latching system may be manually or electromechanically operated. Preferably, a mechanism for activation and release of the latching mechanism may be readily accessible to a person using the tool as in the case with the engagement portion

426

which is readily accessible to either one of the hands of a person operating the power driver.

In the preferred embodiment illustrated, the extension limit position is shown as preferably proximate the retracted position and may, in fact, be the retracted position. When the extension limit position is the retracted position, the housing and slide body are locked together against relative movement. The extension limit position is preferably between the retracted position and the extended position. The attachment could be arranged such that a retracted position in which retraction of the slide body in driving of screws from a collated screwstrip is stopped in normal operation is not a fully retracted position and the extension limit position could be provided to be more retracted than such a normal retracted position. Having the capability of latching the slide body in a position more retracted than a normal retracted position might be advantageous, for example. to have the bit in the fully extended position extend forwardly from the front of the guide tube as, for example, to assist in manually placing a screw on the bit and/or for engagement of the drive shaft

34

and bit

122

as for removal of a bit threadably engaged in the driver shaft. The depth stop mechanism may need to be modified to accommodate an extension limit position beyond the normal retracted position.

The illustrated embodiment shows one catch member

410

provided on slide stop

25

. It is appreciated that the slide stop

25

could carry two or more catch shoulders to permit latching at different extension limit positions.

The illustrated embodiment shows but one form of a mechanism to releasably prevent the housing and slide body from sliding relative each other. Many other embodiments could be provided. For example, another embodiment is a clamp mechanism adapted to be manually operated and to clamp the housing to the slide body to lock each against relative movement. A simple clamp could be carried in a threaded manner on the slide stop

25

of the slide body

20

extending outwardly therefrom with an enlarged head to overlie the housing

18

and to frictionally clamp through the slot

40

of the housing

18

onto the housing

18

as when the head is manually turned in one direction and for release by manual turning in the other direction. Such a clamp for locking the housing relative the slide body could be provided between many different interacting parts of the slide body and housing and, preferably, could be activated to lock the slide body in the fully retracted position.

Additional features of the driver attachment and the interaction of its components is now described with reference to the remaining figures which show the slide body as comprising a rear portion

22

and a removable nose portion

24

. It is to be appreciated that the latching system described is equally operative with a slide body in which the nose portion

24

is not removable as with the rear portion and nose portion

24

being an integral element.

The rear portion

22

comprises a generally cylindrical element

44

with a radially extending flange element

46

on one side. A lever

48

is pivotally mounted to the flange element

46

by bolt

50

for pivoting about an axis

51

of bolt

50

normal to a longitudinal axis

52

which passes centrally through the drive shaft

34

and about which the drive shaft is rotatable. Lever

48

has a forward arm

54

extending forwardly to its front end

56

and a rear arm

58

extending rearwardly to its rear end

60

. A cam follower

62

has its forward end

63

mounted to the rear end

60

of the rear arm

58

by a bolt

64

being received in a slot

65

extending longitudinally in the rear end of the rear arm

58

. The cam follower

62

has at its rear end

66

two cam rollers

67

and

68

rotatable on pins parallel to the axis of bolts

50

and

64

.

As seen in

FIGS. 2 and 4

, the housing

18

carries a camming channel

70

in which the cam rollers

67

and

68

are received. The camming channel

70

is disposed to one side of the driver shaft

34

and extends generally parallel thereto. The camming channel

70

has opposed camming surfaces

71

and

72

at least partially closed by side walls

73

and

74

.

The camming channel

70

extends rearwardly beside the socket

27

of housing

18

and thus rearwardly past the chuck

32

of the power driver

11

to one side thereof. This configuration permits the use of a housing

18

which is of a lesser length parallel longitudinal axis

52

.

A spring

69

wound about bolt

50

is disposed between the flange element

46

and the forward arm

54

of the lever

48

to bias the lever in a clockwise direction as seen in FIG.

4

. The effect of spring

69

is to urge the cam roller

67

into engagement with cam surface

71

and to urge cam roller

68

into engagement with cam surface

72

.

With relative sliding of the slide body

20

and the housing

18

between the extended and the retracted positions, the cam follower

62

translates the relative movement and positioning of the slide body

20

and housing

18

into relative pivoting and positioning of the lever

48

about the axis

51

. The ability of bolt

64

to slide longitudinally in the longitudinal slot

65

provides a lost motion linkage as is known and is advantageous such that the relative timing of pivoting of the lever

48

varies as compared to the relative location of the slide body

20

and housing

18

in moving towards an extended position as contrasted with moving towards a retracted position.

The nose portion

24

has a generally cylindrical screw guide element or guide tube

75

arranged generally coaxially about longitudinal axis

52

and a flange-like screw feed channel element

76

extending radially from the guide tube

75

.

The guide tube

75

has a cylindrical portion

77

at its rear end with a cylindrical exterior surface sized to be closely received, preferably in a friction fit within a forwardly opening cylindrical bore

78

in the forward end of the rear portion

22

. A radially extending key

80

is provided to extend from the cylindrical portion

77

of the nose portion

24

to be received in a correspondingly sized keyway slot in in the rear portion

22

as best seen in

FIGS. 4 and 7

to secure the nose portion

24

to the rear portion

22

against relative pivoting about the longitudinal axis

52

.

The guide tube

75

has a cylindrical bore or guideway

82

extending axially through the guide tube with the guideway

82

delineated and bordered by a radially extending cylindrical side wall

83

and open at its forward axial end

84

and at its rearward axial end

85

.

The guide tube

75

has a rearward section adjacent its rear end

85

in which the side wall

83

extends 360° about the guideway

82

. Forward of the rearward section, the guide tube has a forward section best seen in FIG.

4

and which has an access opening

86

, shown in the drawings as being on the right hand side of the guide tube

75

. Screw access opening

86

is provided to permit the screwstrip

14

including retaining strip

13

and screws

16

to move radially inwardly into the guideway

82

from the right as seen in

FIGS. 4 and 5

. Each screw preferably has a head

17

with a diameter marginally smaller than the diameter of the side wall

83

. It follows that where the head of the screw is to enter the guideway

82

, the screw access opening must have circumferential extent of at least 180°. Where the shank

208

of the screw is to enter the guideway, the screw access opening may have a lesser circumferential extent.

In the forward section, the side wall

83

of the guide tube

75

engages the radially outermost periphery of the head

17

of the screw

16

, to axially locate the screw head

17

coaxially within the guideway

82

in axial alignment with the drive shaft

34

. In this regard, the side wall

83

preferably extends about the screw sufficiently to coaxially locate the screw head and thus preferably extend about the screw head at least 120°, more preferably, at least 150° and most preferably about 180°.

An exit opening

87

, shown towards the left hand side of the guide tube

75

in

FIGS. 4 and 5

, is provided of a size to permit the spent plastic strip

13

from which the screws

16

have been driven to exit from the guideway

82

. Forwardly of the exit opening

87

, the side wall

83

of the guide tube

75

is shown as extending greater than about 180° about the longitudinal axis

52

so as to continue to provide a side wall

83

which can assist and positively coaxially guide the head

17

of a screw

16

being driven.

The screw feed channel element

76

is best seen in

FIGS. 3 and 4

as providing a channelway

88

which extends radially relative the longitudinal axis

52

to intersect with the guideway

82

in the guide tube

75

. In this regard, the channelway

88

opens into the guideway

82

forming the screw access opening

86

. The channelway

88

provides a channel of a cross-section similar to that of the screw access opening

86

from the screw access opening

86

to a remote entranceway opening

90

. The channelway

88

is defined between two side walls

91

and

92

joined by a top wall

93

. The major side wall

91

is shown as extending from the heads

17

of the screws

16

forwardly to at least partially behind the plastic retaining strip

13

. The lesser side wall

92

is shown as extending from the heads

17

of the screws

16

forwardly to above the plastic strip

13

. The side walls

91

and

92

define the channelway

88

with a cross-section conforming closely to that of the screwstrip

14

and its strip

13

and screws

16

with an enlarged width where the heads of the screws are located and an enlarged width where the retaining strip

13

is provided about the screws. The side walls

91

and

92

also have an enlarged funnelling section at the entranceway opening

90

which tapers inwardly to assist in guiding the screwstrip to enter the channelway.

As best seen in

FIG. 3

, the major side wall

91

is provided on its exterior back surface with a raceway

94

extending parallel the channelway

88

and in which a shuttle

96

is captured to be slidable towards and away from the guide tube

75

between an advanced position near the guide tube and a withdrawn position remote from the guide tube. The shuttle

96

has a rear surface

97

in which there is provided a rearwardly directed opening

98

adapted to receive the front end

56

of the forward arm

54

of lever

48

so as to couple the shuttle

96

to the lever

48

for movement therewith.

Shuttle

96

carries a pawl

99

to engage the screwstrip

14

and with movement of the shuttle

96

to successively advance the strip one screw at a time. As seen in

FIG. 6

, the shuttle

96

has a fixed post

100

on which the pawl

99

is journalled about an axis parallel the longitudinal axis

52

about which the driver shaft

34

rotates. The pawl

99

has a strip pusher arm

101

which extends through a slot

103

in the major side wall

91

to engage and advance the screwstrip. The pawl

99

has a manual release arm

102

away from pusher arm

101

and which extends out through a slot

104

in the shuttle

99

. A torsional spring is disposed about post

100

between pawl

99

and shuttle

96

and urges the pusher arm

101

clockwise as seen in FIG.

6

. The spring biases the pusher arm

101

into the screwstrip

14

. The engagement of release arm

102

on the right hand end of slot

104

limits the pivoting of the pawl

99

clockwise to the position shown in FIG.

6

.

The pusher arm

101

of the pawl

99

has a cam face

107

. On the shuttle moving away from the guide tube

75

towards the withdrawn position, i.e., to the left in

FIG. 6

, the cam face

107

will engage the screws

16

and/or the strip

13

and permit the pusher arm

101

to pivot about post

100

against the bias of spring so that the pusher arm

101

may move with the shuttle to the left.

The pusher arm

101

has an engagement face

108

to engage the screws

16

and/or strip

13

. On the shuttle moving towards the guide tube

75

towards the advanced position, i.e., to the right in

FIG. 6

, the engagement face

108

will engage the screws

16

and/or strip

13

and advance the screwstrip to the right as seen in

FIG. 6

so as to position a screw

16

into the guideway

82

in a position to be driven and to hold the screwstrip

14

against movement towards the left.

The release arm

102

permits manual withdrawal of the screwstrip

14

. A user may with his finger or thumb manually pivot the release arm

102

against the bias of spring so that the pusher arm

101

and its engagement face

108

is moved away from and clear of the screwstrip

14

whereby the screwstrip may manually be withdrawn as may be useful to clear jams or change screwstrips.

With the nose portion

24

coupled to the rear portion

22

, the lever

48

couples to the shuttle

96

with the forward arm

54

of lever

48

received in the opening

98

of the shuttle

96

. Sliding of the slide body

20

and the housing

18

in a cycle from an extended position to a retracted position and then back to an extended position results in reciprocal pivoting of the lever

48

about axis

51

which slides the shuttle

96

between the advanced and withdrawn position in its raceway

94

and hence results in the pawl

99

first retracting from engagement with a first screw to be driven to behind the next screw

16

and then advancing this next screw into a position to be driven.

The nose portion

24

is removable from the rear portion

22

. The nose portion

24

and rear portion

22

may be coupled together by axially inserting the cylindrical portion

77

of the guide tube

75

into the bore

78

in the rear portion

22

with the key

80

aligned with the keyway slot

82

and with the front end

56

of the forward arm

54

of the lever

48

aligned with the opening

98

in the shuttle

96

. Thus, the removable nose portion

24

may be coupled to the rear portion

22

merely by axially aligning the nose portion and the rear portion and moving the two elements together in a direction parallel the longitudinal axis

52

.

With the nose portion

24

held on the rear portion

22

by a friction fit. the nose portion

24

can manually be removed by a user merely by the manual application of force. The nose portion

24

is removable from the rear portion

22

without disassembly or uncoupling of any of the remainder of the screwdriver assembly

10

. Thus, the nose portion

24

is removable without uncoupling of the rear portion

22

relative any of the housing

18

, spring

38

, power driver

11

, driver shaft

34

or the screw feed activation mechanism comprising amongst other things the lever

48

and cam follower

62

and without uncoupling of the cam follower

62

in camming channel

70

of the housing

18

.

The nose portion

24

carries the guide tube

75

with its screw locating guideway

82

, the screw feed channel element

76

with its channelway

88

, and screw feed advance mechanism with the reciprocating shuttle

96

and pawl

99

to advance the screwstrip

14

via the channelway

88

into the guideway

82

. Each of the guideway

82

, channelway

88

and shuttle

96

are preferably customized for screwstrips and screws or other fasteners of a corresponding size. In this context, size includes shape, head diameter, shaft diameter, retaining strip configuration, length, spacing of screws along the retaining strip and the presence or absence of washes amongst other things. Different nose portions

24

are to be configured for different screwstrips and screws. The different nose portions

24

are each compatible with the same rear portion

22

and are readily exchangeable so as to permit the driver attachment to be readily adapted to drive different screwstrips and screws.

Many changes can be made to the physical arrangement of the nose portion

24

to accommodate different screws and fasteners. For example, the cross-sectional shape of the channelway

88

can be changed as can the diameter of the guideway

82

. The length of the side walls

91

and

92

about the channelway

88

can be varied to accommodate different size screws which may require greater or lesser engagement.

To adjust for different spacing between screws in different screwstrips, the stroke of the shuttle

96

in reciprocating back and forth can be shortened or lengthened by varying the distance from the axis

51

of the lever

48

to where the shuttle

96

engages the forward arm

54

of the lever

48

. For example, placing the same shuttle

96

in a raceway

94

spaced further from the axis

51

will increase the length of the stroke of the shuttle

96

for the same arc of pivoting of lever

48

. Similarly, using the same shuttle

96

in the same raceway

94

but having the opening

98

in the shuttle

96

to engage the lever

48

farther from the axis

51

will also increase the length of the stroke of the shuttle

96

for the same arc of pivoting of lever

48

.

In contrast with the removable nose portion

24

which is intended to be provided in many different replaceable configurations, the remainder of the driver attachment is preferably of a constant unchanged configuration. In this regard, the remainder of the driver attachment may be characterized by the housing

18

, rear portion

22

of the slide body

20

, drive shaft

34

and spring

38

together with a screw feed activation mechanism comprising the lever

48

cam follower

62

interacting between the rear portion

22

and the housing

18

. This screw feed activation mechanism is activated by relative movement of the housing

18

and rear portion

22

and serves to engage and move the screw feed advance mechanism comprising the shuttle

96

and pawl

99

carried on the nose portion

24

.

The construction of the housing

18

and slide body

20

provide for a compact driver attachment.

The housing

18

has a part cylindrical portion formed by sidewall

301

.

The slide body

20

as best seen in

FIG. 3

comprising the rear portion

22

and nose portion

24

, has a part cylindrical portion of a uniform radius sized to be marginally smaller than the side wall

301

of the housing

18

. The side wall

301

extends circumferentially about the part cylindrical portion of the slide body

20

to retain the slide body

20

therein.

The housing has a flange portion

302

which extends radially from one side of the part cylindrical portion and is adapted to house the radially extending flange

46

of the rear portion

22

and the screw feed activation mechanism comprising the camming channel

70

interacting with the lever

48

and cam follower

62

. The flange portion

302

is open at its front end and side to permit the screw feed channel element

76

to slide into and out of the housing

18

. Concentrically located about the drive shaft

34

is the spring

38

, the part cylindrical portions of the slide body

20

, and the part cylindrical portions of the housing

18

.

The driver attachment is provided with an adjustable depth stop mechanism which can be used to adjust the fully retracted position, that is, the extent to which the slide body

20

may slide into the housing

18

. The adjustable depth stop mechanism is best seen in

FIGS. 2 and 3

as comprising an elongate rod

110

slidably received in an elongate open ended bore

111

provided in the side wall

42

of the housing

18

and extending parallel to longitudinal axis

52

.

A depth setting cam member

114

is secured to the housing

18

for rotation about a pin

116

parallel the longitudinal axis

52

. The cam member

114

has a cam surface

115

which varies in depth, parallel the longitudinal axis

52

, circumferentially about the cam member

114

. A portion of the cam surface

115

is always axially in line with the rod

110

. A spring

112

biases the rod

110

rearwardly such that the rear end

117

of the rod engages the cam surface

115

. The spring

112

is disposed between the housing and a pin

112

on the rod. By rotation of the cam member

114

, the extent to which the rod

110

may slide rearwardly is adjusted.

The rod

110

has a front end

118

which extends forwardly from bore

111

for engagement with rearwardly directed annular stop surface

119

provided on the nose portion

24

of the slide body. The slide body

20

is prevented from further sliding into the housing

18

when the front end

118

of the rod

110

engages the stop surface

119

. The extent the slide body

20

may slide into the housing

18

is determined by the length of the rod

110

and the depth of the cam member

114

axially in line with the rod. The cam member

114

is preferably provided with a ratchet-like arrangement to have the cam member

114

remain at any selected position biased against movement from the selected position and with circular indents or depressions in the cam surface

115

to assist in positive engagement by the rear end

117

of the rod. The cam member

114

is accessible by a user yet is provided to be out the way and not interfere with use of the driver attachment. The nose portion

24

may be customized for use in respect of different size screws by having the location of the stop surface

119

suitably provided axially on the nose portion

24

as may be advantageous for use of different size screws.

The driver shaft

34

is shown in

FIGS. 4 and 5

as carrying a split washer

120

engaged in an annular groove near its rear end

121

to assist in retaining the rear end of the driver shaft in the socket

27

of the housing

18

. The driver shaft

34

is provided with a removable bit

122

at its forward end which bit can readily be removed for replacement by another bit as for different size screws. Such bits include sockets and the like in any replacement bits will preferably be of an outside diameter complementary to the inside diameter of the guideway

82

in a corresponding replacement nose portion adapted for use with a corresponding sized screws. To accommodate bits of increased diameter over the bit shown in

FIGS. 4 and 5

, the guideway

82

of the guide tube

75

may be provided with an increased radius, at least commencing at the location where the bit may have an enlarged diameter and extending forwardly therefrom. The guideway

82

in the guide tubes

75

may thus have a step configuration with the side wall

83

being of a reduced diameter where the driver shaft

34

enters the rear of the guide tube

75

and the sidewall

83

may then increase to an enlarged diameter forwardly to accommodate an enlarged bit such as a socket.

The rear portion

22

is shown in

FIGS. 4 and 5

as having a radially inwardly extending annular flange

19

which provides the end of the forwardly opening bore

78

as well as the end of a rearwardly opening bore

79

within which the spring

38

is received. The annular flange

19

has an opening therethrough of a diameter slightly larger than the diameter of the driver shaft

34

so as to assist in journalling the driver shaft therein. The opening through the annular flange

19

may however be increased so as to facilitate the use of driver shafts

34

having enlarged diameters as well as a driver shafts

34

having reduced diameters.

Insofar as the driver shaft

34

has a removable bit

122

, it is preferred that as shown, when the driver attachment

12

is in the fully extended position and the nose portion

24

is removed, the bit

122

be readily accessible for removal and replacement. In this regard, it is preferred that the nose portion

24

have a guideway

82

of a minimum diameter throughout its length at least equal to the diameter of the bit

122

such that the nose portion

24

may be removed from the rear portion

22

without the need to remove the bit

122

as may otherwise be the case in the event the guideway

82

may have a stepped configuration.

Operation of the driver attachment is now explained with particular reference to

FIGS. 4 and 5

. As seen in

FIG. 4

, the screws

16

to be driven are collated to be held parallel and spaced from each other by the plastic retaining strip

13

.

In operation, a screwstrip

14

containing a number of screws

16

collated in the plastic retaining strip

13

is inserted into the channelway

88

with the first screw to be driven received within the guideway

82

. To drive the first screw into the workpiece

124

, the power driver

11

is activated to rotate the driver shaft

34

. The driver shaft

34

and its bit

122

, while they are rotated, are reciprocally movable in the guideway

82

towards and away from the workpiece

124

. In a driving stroke, manual pressure of the user pushes the sousing

18

cowards the workpiece

124

. With initial manual pressure, the forward end

23

of the nose portion engages the workpiece

124

to compress spring

38

so as to move slide body

20

relative the housing

18

into the housing

18

from an extended position shown in

FIG. 4

to a retracted position. On release of this manual pressures in a return stroke, the compressed spring

38

moves the slide body

20

back to the extended position thereby moving the housing

13

and the driver shaft

34

away from the workpiece.

In a driving stroke, as the driver shaft

34

is axially moved towards the workpiece, the bit

122

engages the screw head

17

to route the first screw to be driven. As is known, the plastic strip

13

is formed to release the screw

16

as the screw

16

advances forwardly rotated by the driver shaft

34

. Preferably, on release of the screw

16

, the plastic strip

13

deflects away from the screw

16

outwardly so as to not interfere with the screw

16

in its movement into the workplace. After the screw

16

is driven into the workpiece

124

, the driver shaft

34

axially moves away from the workpiece under the force of the spring

38

and a successive screw

16

is moved via the screw feed advance mechanism from the channelway

88

through the access opening

86

into the guideway

82

and into the axial alignment in the guideway with the driver shaft

34

.

The screw

16

to be driven is held in position in axial alignment with the driver shaft

34

with its screw head

17

abutting the side wall

83

in the guideway

82

. As a screw

16

to be driven is moved into the cylindrical guideway

82

, a leading portion of the strip

13

′ from which screws have previously been driven extends outwardly from the guideway

83

through the exit opening

87

permitting substantially unhindered advance of the screwstrip

14

.

To assist in location of a screw to be driven within the guide tube

75

, in the preferred embodiment the exit opening

87

is provided with a rearwardly facing locating surface

125

adapted to engage and support a forward surface

222

of the strip

13

. Thus, on the bit

122

engaging the head of the screw and urging the screw forwardly, the screw may be axially located within the guide tube

75

by reason not only of the head of the screw engaging the side wall

83

of the guideway but also with the forward surface

222

of the strip

13

engaging the locating surface

125

of the exit opening

87

. In this regard, it is advantageous that the forward surface

222

of the retaining strip

13

be accurately formed having regard to the relative location of the screws

16

and particularly the location of the their heads

17

. The forward surface

222

of the strip

13

may be complementary formed to the locating surface

125

and if desired indexing notches or the like may be provided in the forward surface

222

of the strip

13

to engage with complementary notches or indents on the locating surface

125

of the entranceway to assist in indexing location of the strip

13

relative the locating surface and enhance the location thereby of the screw

16

within the guide tube

75

.

In the embodiment of the nose portion

24

shown in

FIGS. 1

to

6

, on the bit

122

engaging the head

17

of the screw

16

and urging it forwardly in the guideway

82

, the strip

13

is preferably held against movement forwardly firstly by the forward surface

222

of the strip engaging locating surface

125

and, secondly. by the under surfaces of the heads

17

of screws in the channelway

88

engaging on the rearwardly directed shoulders provided on each of the side walls

91

and

92

where the enlarged width cross-section of the channelway

88

accommodating the head of the screws reduces in width as seen in FIG.

3

. Together with the location of the head

17

of a screw

16

coaxially in the guideway, the screw

16

to be driven is located axially aligned with the driver shaft without any moving parts other than the advance shuttle

96

.

The driver attachment

12

disclosed may be provided for different applications. In a preferred application, the driver may be used for high volume heavy load demands as, for example, as in building houses to apply sub-flooring and drywall. For such a configuration, it is preferred that with the power driver

11

comprising a typical screw gun which inherently incorporates a friction clutch and thus to be extent that a screw is fully driven into a workpiece, the clutch will, on the forces require to drive the screw becoming excessive, slip such that the bit will not be forced to rotate an engagement with the screw head and thus increase the life of the bit.

The driver attachment in accordance with the present invention is, however, adaptable for use with conventional power drills which are similar to screw guns yet do not incorporate a clutch mechanism. The driver attachment may be suitably used with a drill without a clutch preferably with the user manipulating the drill and driver attachment in use to reduce the likelihood of bit wear by the bit rotating relative the screw head in a jamming situation.

The driver attachment may be constructed from different materials of construction having regard to characteristics of wear and the intended use of the attachment. Preferably, a number of the parts may be molded from nylon or other suitably strong light weight materials. Parts which are subjected to excessive wear as by engagement with the head of the screw may be formed from metal or alternatively metal inserts may be provided within an injection molded plastic or nylon parts. The provision of a removable nose portions

24

also has the advantage of permitting removable nose portion to be provided with surfaces which would bear the greatest loading and wear and which nose portions may be easily replaced when worn.

The screw feed advance mechanism carried on the nose portion has been illustrated merely as comprising a reciprocally slidable shuttle carrying a pawl. Various other screw feed advance mechanisms may be provided such as those which may use rotary motion to incrementally advance the screws. Similarly, the screws feed activation mechanism comprising the lever

48

and the cam follower have been shown as one preferred mechanism for activating the screw feed advance mechanism yet provide for simple uncoupling as between the shuttle

96

and the lever

48

. Other screw feed activation means may be provided having different configurations of cam followers with or without levers or the like.

In the preferred embodiment, the screwstrip

14

is illustrated as having screws extending normal to the longitudinal extension of the strip

13

and in this context, the channelway

88

is disposed normal to the longitudinal axis

52

. It is to be appreciated that screws and other fasteners may be collated on a screwstrip in parallel spaced relation however at an angle to the longitudinal axis of the retaining strip in which case the channelway

88

would be suitably angled relative the longitudinal axis so as to locate and dispose each successive screw parallel to the longitudinal axis

52

of the driver shaft.

A preferred collated screwstrip

14

for use in accordance with the present invention is as illustrated in the drawings and particularly FIG.

3

and are substantially in accordance with Canadian Patent 1,054,982. The screwstrip

14

comprises a retaining strip

13

and a plurality of screws

16

. The retaining strip

13

comprises an elongate thin band formed of a plurality of identical sleeves interconnected by lands

106

. A screw

16

is received within each sleeve. Each screws

16

has a head

17

, a shank

208

carrying external threads

214

and a tip

15

. As shown, the external threads extend from below the head

17

to the tip

15

.

Each screw is substantially symmetrical about a central longitudinal axis

212

. The head

17

has in its top surface a recess

213

for engagement by the screwdriver bit.

Each screw is received with its threaded shank

208

engaged within a sleeve. In forming the sleeves about the screw, as in the manner for example described in Canadian Patent 1,040,600, the exterior surfaces of the sleeves come to be formed with complementary threaded portions which engage the external thread

214

of the screw

16

. Each sleeve has a reduced portion between the lands

106

on one side of the strip

13

. This reduced strength portion is shown where the strip extends about each screw merely as a thin strap-like portion or strap

220

.

The strip

13

holds the screw

16

in parallel spaced relation a uniform distance apart. The strip

13

has a forward surface

222

and a rear surface

223

. The lands

106

extend both between adjacent screws

16

, that is, horizontally as seen in

FIG. 3

, and axially of the screws

16

, that is, in the direction of the longitudinal axes

212

of the screws. Thus, the lands comprise webs of plastic material provided over an area extending between sleeves holding the screws and between the forward surface

222

and the rear surface

223

. A land

106

effectively is disposed about a plane which is parallel to a plane in which the axes

212

of all the screws lies. Thus, the lands

106

comprise a web which is disposed substantially vertically compared to the vertically oriented screws as shown in the figures. The lands

106

and the sleeves, in effect, are disposed as continuous, vertically disposed strip

13

along the rear of the screws

16

, that is, as a strip

13

which is substantially disposed about a plane which is parallel to a plane containing the axes of all screws.

A preferred feature of the screwstrip

14

is that it may bend to assume a coil-like configuration due to flexibility of the lands

106

, such that, for example, the screwstrip could be disposed with the heads of the screws disposed into a helical coil, that is. the plane in which all the axes

212

of the screws lie may assume a coiled, helical configuration to closely pack the screws for use. Having the lands

106

and sleeves as a vertically extending web lying in the plane parallel that in which the axes

212

permits such coiling.

The invention is not limited to use of the collated screwstrips illustrated. Many other forms of screwstrips may be used such as those illustrated in U.S. Pat. No. 3,910,324 to Nasiatka: U.S. Pat. No. 5.083,483 to Takaji; U.S. Pat. No. 4,019,631 to Lejdegard et al and U.S. Pat. No. 4.018,254 to DeCaro.

Reference is now made to

FIGS. 14 and 15

illustrating a second embodiment of a removable rose portion

24

which is adapted for substitution with the nose portion

24

illustrated in

FIGS. 1

to

6

. Throughout

FIGS. 14 and 15

, similar reference numbers are used to refer to similar elements in

FIGS. 1

to

11

. For simplicity, the nose portion

24

shown in

FIGS. 14 and 15

is shown merely in the context of the nose portion and/or with a screwstrip

14

including retaining strip

13

and screws

16

. Other elements such as the shuttle

96

, the shuttle pawl

99

, the lever

48

, the drive shaft

34

, the bit

122

and the workpiece

124

are not shown for the purposes of simplicity. However, operation and interaction of various parts is substantially the same.

The nose portion

24

of

FIGS. 14 and 15

is identical to the nose portion

24

of

FIGS. 1

to

6

other than in the configuration of a passageway for the screwstrip radially through the guide tube

75

from the screw access opening

86

to the exit opening

87

.

In

FIGS. 1

to

6

, the guide tube

75

has an outboard side which is completely cut away between the screw access opening

86

and the exit opening

87

. In

FIGS. 14 and 15

, the guide tube

75

is not completely cut away on its outboard side but rather has a continuous portion

382

of its outer wall which separates the screw access opening

86

from the exit opening

87

on the outboard side of the guide tube

75

. As used herein, the outboard side is the side to which the strip

13

is deflected when a screw

16

is separated from the screwstrip

14

.

To accommodate deflection of the strip

13

away from a screw

16

towards the outboard side, the passageway which extends from the screw access opening or entranceway

86

to the exit opening or exitway

87

is provided on its outboard side with a lateral strip receiving slotway cut to extend to the outboard side from the cylindrical guideway

82

.

The access opening

86

forms an entranceway for the screwstrip

14

generally radially into the guideway

82

on one side. The exit opening

87

forms an exitway for portions of the strip

13

from which screws

16

have been driven.

The exit openings or exitway

87

is shown as adapted to encircle the spent strip

13

with the exitway

87

bordered by rearwardly directed forward surface

125

, forwardly directed rear surface

312

, inboard side surface

314

and outboard side surface

316

.

In

FIGS. 14 and 15

, the screwstrip

14

has been shown in a preferred form for screwstrips which are to comprise discrete length segments. The strip, as seen in

FIGS. 14 and 15

, has lands

106

of relatively constant cross-section throughout the length of the strip, with an enlarged flange

107

extending along the outboard side of the strip. This structure and particularly the enlarged flange

107

assists in making the strip self-supporting, that is, so that a segment will support the weight of the screws against bending. Flange

107

extends in the axial direction of the screw at least half the height of the lands.

The nose portion

24

is shown as removable for use in an assembly as illustrated. It is to be appreciated that the particular features of the exitway, entranceway and guideway specifically disclosed to assist in driving the last screw in a strip could be used in other guide tubes such as those which are not removable and which may or may not have an associated channelway.

The driver attachment

12

in accordance with this invention and the nose portion

24

described herein are particularly adapted for driving screwstrips

14

in the form of short segments, preferably in the range of about six to eighteen inches in length. One preferred length is about twelve inches so as to hold, for example, about 32 screws of, for example, drywall screws or wood screws. To provide each segment with sufficient rigidity to be self-supporting, it is preferred to provide the strip

13

to have increased dimensions normal the axis of the screw on the outboard side of the screws as, for example, with the lands

106

extending as a continuous web along the outboard side of the screws as seen in FIG.

14

. Reinforcing rib or flange

107

may be provided along the entire length of the strip as seen in FIG.

14

. Such a reinforcing flange

107

or rib is of assistance in maintaining the axis of the screws in the same plane against coiling. The enlarged slotway in the nose portion of

FIG. 14

is readily adapted to accommodate strips of increased width with such lands and ribs as shown.

Preferred strip segments for use with the drive attachment in accordance with this invention are as shown in

FIG. 14

, segments of discrete length in which the axis of all strips lie in the same flat plane and in which the heads

17

of the screws are all located in a straight line.

Reference is now made to the embodiment shown in

FIGS. 16

to

20

. The embodiment of

FIG. 16

is substantially the same as the embodiment illustrated in

FIGS. 2

to

7

, however, with the cam follower

62

of

FIG. 2

removed and a separate camming mechanism being provided by a pin

502

being provided on rear arm

58

to be received in a cam slot

506

in the side wall

302

of the housing

18

with camming surfaces

508

and

510

to selectively engage the pin

502

and appropriately move the rear arm

58

with extension and retraction of the slide body in the housing. As shown, the flange element

46

in

FIG. 16

has been extended rearwardly as a substantially elongated rearwardly extending side flange element

46

. As well. a depending side flange element

546

is provided.

The embodiment of

FIG. 16

has also been modified so as to provide what was previously the camming channel

70

in the embodiment of

FIG. 2

as a passageway of generally L-shape in horizontal cross-section as seen in FIG.

16

. which L-shaped channel

70

is sized so as to permit the side flange element

46

and its depending side flange element

546

to be axially slidable therein.

Reference is made to

FIG. 18

which shows a schematic cross-sectional view along section line

18

—

18

′ in FIG.

16

. As shown, the housing

18

has a bore

624

extending therethrough adjacent the L-shaped channel

70

within which there is received a locking mechanism

622

. The locking mechanism

622

is schematically shown in an exploded pictorial view in

FIG. 19

as comprising a locking lever

626

secured to a shaft rod

628

which carries at its lower end an eccentric cam or wedge member

630

. A screw

632

is shown to secure the lever

626

to the rod

628

against relative rotation. Similarly, the wedge member

630

is secured to the rod

628

against relative rotation.

The wedge member

630

is secured to the rod such that relative rotation of the rod

628

within the bore

624

by means of manual movement of the lever

626

will cause side surfaces

632

of the wedge member

630

to move towards or away from the inner side surface

72

of the channel

70

. The wedge member

630

is preferably shown as comprising a frustoconical member secured, however, eccentrically from the center axis through the frustoconical member yet mounted for rotation parallel the center axis of the frustoconical member.

Reference is made to

FIG. 20

which shows the latching mechanism with the lever

626

rotated into a position such that the wedge member

630

has its side surface

632

spaced away from side wall

72

a distance greater than the thickness of the side flange element

46

. With the locking mechanism in the position shown in

FIG. 20

, the side flange elements

46

and

546

are free to slide axially within the L-shaped channel

70

.

FIG. 18

shows the locking lever

626

in a locked position as shown in

FIG. 16

in which the wedge member

630

carried by the rod

628

has been rotated into a position in which the wedge-shaped member

630

is placed sufficiently close to the side surface

72

so as to have the side flange element

46

frictionally engaged between the wedge member

630

and the side surface

72

. By creating frictional forces holding the side flange element

46

to be greater than those developed by the spring

38

, the slide body is locked in the retracted position.

As seen in

FIG. 18

, the wedge member has side surface

632

which extend away from the side surface

72

as they extend forwardly. This sloped side surface

632

permits the side flange element

46

to be forced rearwardly past the wedge member

360

into the locked position shown in

FIG. 18

on retraction of the slide body into the housing.

In use, it is to be appreciated that the locking mechanism may be moved to the latched position as shown in

FIG. 18

while the slide body is in an extended position. On subsequent retraction of the slide body into the housing, the side flange element

46

will be forced rearwardly past the wedge member

360

into a frictionally engaged configuration as shown in

FIG. 18

against forward extension under the force of the spring

38

until such time as the locking mechanism is moved by movement of the lever

626

to an unlocked position as shown in FIG.

20

.

As well, if the slide body may be retracted to the fully retracted position as shown in

FIG. 18

with the latching mechanism in the unlocked position, with the slide body in the retracted position as seen in

FIG. 20

, it is then possible to manually move the lever to the locked position as shown in

FIG. 18

so as to lock the side flange element

46

in the channel

70

.

In the embodiment shown in

FIG. 16

, the wedge member

630

is shown as being generally frustoconical. This is not necessary and it may have many other configurations, the dominant characteristic being that, on rotation of the wedge member, portions of the wedge member move closer to and/or away from the walls of the channel

70

. The embodiment of

FIG. 16

has been discussed with the wedging effect being achieved between the wedge member

630

and the side wall

72

. It is also to be appreciated that in substitution thereof or in combination therewith, similar wedging could be provided between the wedge member

630

and the side wall

73

by clamping the side flange element

546

therebetween.

In the embodiment illustrated in

FIG. 16

, the side flange element

46

and the side flange element

546

are shown as having uniform thickness. It is to be appreciated that either of these could taper. For example, the side flange element

46

could reduce in thickness as it extends rearwardly and upwardly as seen in

FIG. 18

to assist in increasing the frictional forces by which it is wedged between the wedge member

630

and the side surface

72

with relative movement rearwardly.

It is to be appreciated that in the embodiment of

FIGS. 2

to

7

, the latching system utilizes catch members which mechanically engage opposing rearwardly and forwardly directed engagement surfaces. In contrast, in the embodiment as illustrated in

FIGS. 16

to

20

, the latching system utilizes catch members which frictionally engage opposing side surfaces as in the manner of a friction clutch mechanism.

The friction catch member system of

FIGS. 16

to

20

can be adapted to be a mechanical catch member system as follows.

The wedge member

630

has an upper edge

648

between its rear surface

650

and its side surface which is relatively sharply defined as may assist in frictionally engaging the side flange element

46

. The side flange element

46

may be provided with one or more vertically spaced, horizontally extending, forwardly directed shoulders for positive engagement by the upper edge

648

of the wedge member

630

and with engagement upon different of the shoulders dependent on the extent to which the slide body is retracted.

As a further modification, the side flange element

46

could carry a catch member which only mechanically catches with the wedge member when the wedge member is in the locked position and save for the catch member, the side flange element

46

is always slidable in the channel

70

.

FIG. 19

shows a helical spring

634

to be disposed about rod

628

and located about the rod

628

between the rear upper surface of the wedge member

630

and a lower surface of the housing about the bore

624

. The purpose of this spring is to assist, once the lever

626

is placed in any position, in frictionally keeping the lever in that position against movement. Various other mechanisms could be provided to lock the locking lever

626

in any position in which it is to be manually placed. Of course, the locking lever

626

could be replaced by other manually operated mechanisms such as a rotatable thumb screw.

While the invention has been described with reference to preferred embodiment, the invention is not so limited. Many variations and modifications will now occur to persons skilled in the art. For a definition of the invention, reference is made to the appended claims.

Claims

1. An apparatus for driving with a power driver a screwstrip comprising threaded fasteners which are joined together in a holding strip comprising:a housing; an elongated drive shaft for operative connection to a power driver for rotation thereby and defining a longitudinal axis; a slide body coupled to the housing for displacement parallel to the axis of the drive shaft between an extended position and a retracted position; a screw feed advance mechanism to engage the screwstrip and successively, incrementally advance fasteners on the screwstrip into axial alignment with said drive shaft for driving of successive fasteners by drive shaft; an extension limit mechanism activatable to assume an activated configuration and an inactivated configuration, a manual switch for manual operation by a user to switch the extension limit mechanism between the activated configuration and the inactivated configuration, in the activated configuration, the extension limit mechanism does not impede relative sliding of the housing and the slide body between the extended position and the retracted position, in the activated configuration, when the housing and slide body are retracted beyond an extension limit position disposed toward the retracted position from the extended position the extension limit mechanism prevents the housing and slide body from being extended relative each other towards the extended position beyond the extension limit position, in the activated configuration, the extension limit mechanism does not impede the housing and the slide body from being retracted to the extension limit position-towards the retracted position.
2. An apparatus as claimed in claim 1 wherein the elongate drive shaft has a rearmost end for operative connection to a power driver for rotation thereby and a forwardmost end carrying a fastener engaging bit,the slide body carrying guide means about the axis to locate successive of the fasteners in the holding strip advanced by the screw feed advance mechanism axially in alignment with the drive shaft for driving forwardly by the bit out of the holding strip and from the guide means, the slide body also carrying a guide channel extending transversely to the axis to guide the holding strip containing fasteners into the guide means.
3. An apparatus as claimed in claim 2 wherein in the extension limit position the bit is located forward from the holding strip received in the guide means.
4. An apparatus as claimed in claim 2 including a release mechanism activable to permit withdrawal of the screwstrip from the guide channel, the release mechanism activatable whether or not the extension limit mechanism is activated and whether or not the slide body is prevented from being extended relative the housing beyond the extension limit position.
5. An apparatus as claimed in claim 2 wherein when the housing and slide body are in the extension limit position, the bit being accessible radially through the slide body and the housing via complementary radially extending access slots in the same side of the slide body and the housing for removal of the bit from the drive shaft.
6. An apparatus as claimed in claim 2 wherein when the extension limit mechanism is activated, the drive shaft remains rotatable.
7. An apparatus as claimed in claim 2 wherein the guide channel guides the holding strip from which fasteners have been driven out of the guide means and the guide means having an entranceway for entry of the holding strip carrying threaded fasteners from the guide channel and an exitway for exit of the holding strip from which fasteners have been driven.
8. An apparatus as claimed in claim 1 wherein the extension limit position is proximate the retracted position.
9. An apparatus as claimed in claim 1 wherein the extension limit position is the retracted position.
10. An apparatus as claimed in claim 1 including a screwdriving depth adjustment mechanism to adjustably prevent the housing and slide body from being retracted relative each other towards the retracted position beyond a retracted limit position, and wherein when the extension limit mechanism is activated, the screw driving depth adjustment mechanism remains operative for adjustment.
11. An apparatus as claimed in claim 10 wherein the screwdriving depth adjustment mechanism is adjustable to set the retracted limit position at the extended position or spaced from the extended position.
12. An apparatus as claimed in claim 1 wherein the screw feed advance mechanism is coupled between the slide body and the housing whereby displacement of the slide body relative the housing between the extended position and the retracted position activates the screw feed advance mechanism to advance successive fasteners.
13. An apparatus as claimed in claim 1 including a spring biasing the slide body forwardly relative to the housing parallel the axis to the extended position.
14. An apparatus as claimed in claim 1 the extension limit mechanism only switching from the activated configuration to the inactivated configuration by manual operation by a user of the manual switch.
15. An apparatus as claimed in claim 1 wherein in the activated configuration, while the housing and slide body are extended beyond the extension limit position, the extension limit mechanism does not impede relative sliding of the housing and the slide body toward the extended position.
16. An apparatus as claimed in claim 1 wherein in the activated configuration, while the housing and slide body are extended beyond the extension limit position, the extension limit mechanism does not impede relative sliding of the housing and the slide body between the extension limit position and the extended position,in the activated configuration, while the housing and slide body are retracted beyond the extension limit position, the extension limit mechanism does not impede relative sliding of the housing and the slide body between the extension limit position and the retracted position, and in the activated configuration, the extension limit mechanism does not impede relative sliding of the housing and the slide body towards the retracted position through the extension limit position.
17. An apparatus as claimed in claim 1 wherein the extension limit mechanism comprises a friction clutch mechanism.
18. An apparatus for driving with a power driver a screwstrip comprising threaded fasteners which are joined together in a holding strip comprising:a housing; an elongate drive shaft for operative connection to a power driver for rotation thereby and defining a longitudinal axis; a slide body coupled to the housing for displacement parallel to the axis of the drive shaft between an extended position and a retracted position; a screw feed advance mechanism to engage the screwstrip and successively, incrementally advance fasteners on the screwstrip into axial alignment with said drive shaft for driving of successive fasteners by drive shaft; an extension limit mechanism activatable to assume an activated configuration and an inactivated configuration, in the activated configuration, the extension limit mechanism does not impede relative sliding of the housing and the slide body between the extended position and the retracted position, in the activated configuration, when the housing and slide body are retracted beyond an extension limit position disposed toward the retracted position from the extended position, the extension limit mechanism prevents the housing and slide body from being extended relative each other towards the extended position beyond the extension limit position, in the activated configuration, the extension limit mechanism does not impede relative sliding of the housing and the slide body from being retracted to the extension limit position towards the retracted position, wherein the elongate drive shaft has a rearmost end for operative connection to a power driver for rotation thereby and a forwardmost end carrying a fastener engaging bit, the extended position is forward of the retracted position; the slide body carrying guide means about the axis to locate successive of the fasteners in the holding strip advanced by the screw feed advance mechanism axially in alignment with the drive shaft for driving forwardly by the bit out of the holding strip and from the guide means, the slide body also carrying a guide channel extending transversely to the axis to guide the holding strip containing fasteners into the guide means, and wherein the forward end of the drive shaft carries a forwardly opening socket, the bit frictionally received in the socket for removal by axially directed forces, a radially inwardly directed removal slot provided on the drive shaft rearward of the bit and adapted for the radial insertion of a lever tool radially into the removal slot for levered engagement of the bit to urge the bit axially forwardly for removal, wherein when the housing and slide body are in the extension limit position, the bit and the slot being accessible radially through the slide body and the housing via complementary radially extending access slots in the same side of the body and the housing.
19. An apparatus for driving with a power driver a screwstrip comprising threaded fasteners which are joined together in a holding strip comprising:a housing; an elongate drive shaft for operative connection to a power driver for rotation thereby and defining a longitudinal axis; a slide body coupled to the housing for displacement parallel to the axis of the drive shaft between an extended position and a retracted position; a screw feed advance mechanism to engage the screwstrip and successively, incrementally advance fasteners on the screwstrip into axial alignment with said drive shaft for driving of successive fasteners by drive shaft; an extension limit mechanism activatable to assume an activated configuration and an inactivated configuration, in the activated configuration, the extension limit mechanism does not impede relative sliding of the housing and the slide body between the extended position and the retracted position, in the activated configuration, when the housing and slide body are retracted beyond an extension limit position disposed toward the retracted position from the extended position, the extension limit mechanism prevents the housing and slide body from being extended relative each other towards the extended position beyond the extension limit position, in the activated configuration, the extension limit mechanism does not impede relative sliding of the housing and the slide body from being retracted to the extension limit position towards the retracted position, wherein the extension limit mechanism comprises a first catch member on the slide body and a second catch member on the housing; one of the first and second catch members being manually adjustable to assume either an activated or an inactivated position, wherein with the adjustable one of the first and second catch members in the activated position, the first and second catch members do not prevent the housing and slide body from being retracted relative each other, however, when the slide body and housing are retracted beyond the extension limit position, the first and second catch members are engagable to prevent the housing and slide body from being extended relative each other beyond the extension limit position, and wherein with the adjustable one of the first and second catch members in the inactivated position, the first and second catch members do not engage to impede relative sliding of the housing and the slide body.
20. An apparatus as claimed in claim 19 including an activation member for manual engagement to locate the adjustable one of the first and second catch members in either its activated or inactivated position.
21. An apparatus as claimed in claim 19 including a spring biasing the slide body forwardly relative to the housing, and wherein the extension limit position is between the extended position and the retracted position and when the extension limit mechanism is activated and the first and second catch members are in engagement preventing the slide body from moving towards the extended position, to release the first and second catch members from engagement requires initial retraction of the slide body against the bias of the spring towards the retracted position from the extension limit position.
22. An apparatus for driving with a power driver a screwstrip comprising threaded fasteners which are joined together in a holding strip comprising:a housing; an elongated drive shaft for operative connection to a power driver for rotation thereby and defining a longitudinal axis; a slide body coupled to the housing for displacement parallel to the axis of the drive shaft between an extended position and a retracted position; a screw feed advance mechanism to engage the screwstrip and successively, incrementally advance fasteners on the screwstrip into axial alignment with said drive shaft for driving of successive fasteners by drive shaft; and a selectively activatable latching system operatively connected with said housing and said slide body, said latching system, when activated, defining a limit position between said extended position and said retracted position and, when the slide body is displaced relative to the housing between said retracted position and said limit position, said latching system prevents displacement of said slide body toward said extended position beyond said limit position.

PRIORITY CLAIM

This application claims the priority of international application PCT/CA98/00432, filed Apr. 24, 1998, and is a continuation-in-part of the priority of U.S. application Ser. No. 08/741,278 filed Oct. 30, 1996 now U.S. Pat. No. 5,855,151.

PCT Information

Filing Document	Filing Date	Country	Kind
PCT/CA98/00432		WO	00

Publishing Document	Publishing Date	Country	Kind
WO99/55494	11/4/1999	WO	A

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Continuation in Parts (1)

	Number	Date	Country
Parent	08/741278	Oct 1996	US
Child	09/673917		US

Lockable telescoping screwdriver

Information

Patent Number

Date Filed

Date Issued

Inventors

Examiners

Agents

CPC

US Classifications

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US