Fastener Driving Tool

Abstract

A stapler or nailer for applying such fasteners to inaccessible workpiece locations includes a "long nose" or extended nosepiece structure forming a drive track. Although the drive track is greatly elongated compared to a conventional tool, a fastener driving blade and a coupled piston-cylinder motor do not require corresponding longer operating strokes because the fastener is advanced through the drive track in steps on successive driver blade strokes of conventional length. This incremental movement is obtained by using a stepped driver blade to move, on successive strokes of the driver blade, a fastener supplied from a magazine through one or more fastener storage or retaining stations spaced along the drive track to a discharge opening at the lower end of the drive track.

Description

The present invention relates to a fastener applying tool and, more particularly, to such a tool which requires only a normal operating stroke while providing a substantially elongated nosepiece.

Fastener applying or driving tools such as pneumatically actuated staplers and nailers are frequently used in applications in which it is necessary to provide a large clearance between the end of the nosepiece structure from which the nail or staple is driven into a workpiece and the remainder of the tool housing. In most tools, the magazine assembly extending rearwardly from the point on the nosepiece at which the fasteners are fed into the drive track provides the structure that limits the clearance. Since the lower end of the fastener driver is usually disposed just above the fastener at the point in the drive track at which the fastener is supplied by the magazine assembly, any increase in the length of the clearance between the workpiece engaging end of the nosepiece and the magazine must be accompanied by an increase in the stroke of the driver and its connected piston.

As an example, U.S. Pat. No. 3,190,522 discloses a group of pneumatic stapling tools for fastening coil springs to a frame in which the size of the coil springs necessitates a large clearance between the staple magazine and the workpiece engaging end of the nosepiece. This clearance is supplied by providing a "long nose" on the tool with an increase in the length of the cylinder and the piston-driver blade stroke. This increased tool size results in stationary assembly fixtures that are larger than desirable and in tools that are unwieldy to operate manually. The necessity of increasing the cylinder length to provide the increased stroke required by the "long nose" tool also means that "long nose" tools must be specially designed and that the standard pneumatic motor drive systems for the large volume hand tools cannot be used in "long nose" applications.

Accordingly, one object of the present invention is to provide a new and improved fastener applying tool.

Another object is to provide a fastener driving tool with a nosepiece or drive track of substantially increased length that does not require an increased stroke for the driver operating means.

A further object is to provide a "long nose" fastener driving tool capable of being operated by pneumatic motors used in conventional tools.

A further object is to provide a fastener driving tool in which a fastener, such as a staple or nail, is advanced through a drive track in increments by a series of strokes of an operating means.

A further object is to provide a fastener driving tool including one or more fastener storage or retaining stations spaced along a drive track.

Another object of the present invention is to provide a fastener applying tool for driving a fastener through a drive track in a plurality of strokes in which the drive track and a fastener driver movable therein have sections of different widths or thicknesses.

A further object is to provide a fastener applying tool with a drive track having fastener storage assemblies for storing fasteners in the drive track wherein the storage assemblies include means for retaining a fastener against retrogressive movement and for transferring the fastener to different sections of the drive track.

In accordance with these and many other objects, an embodiment of the present invention comprises a pneumatically actuated fastener driving or applying tool having a substantially elongated nosepiece structure affording a substantial clearance between the fastener discharging opening in the lower end of the nosepiece and the remainder of the tool housing so as to afford a tool capable of reaching inaccessible workpiece locations. This is accomplished without increasing the length of the operating stroke of the fastener blade slidably mounted in the drive track and its connected pneumatic piston by provding one or a number of fastener storing or retaining stations spaced along the length of the drive track. The fastener driving blade is provided with a series of corresponding stepped fastener engaging portions, the upper one of which is disposed adjacent the point at which fasteners are supplied to the drive track from a magazine and the remainder of which are disposed adjacent successive fastener storing stations.

Accordingly, when the tool is first operated following the provision of a supply of fasteners in the magazine, the first fastener such as a staple is transferred from its point of introduction into the drive track to the first storing station by the related portion of the driver blade, and no fastener is applied to the workpiece. The first transferred fastener is retained in the storage station as the driver blade is retracted to its normal position. When the driver blade is retracted, the storage station transfers the fastener beneath the next step on the driver blade. Accordingly, when the tool is next operated, the staple in the storage station is either driven into the workpiece or transferred to a subsequent storage station, while the uppermost step on the driver blade transfers a fastener or staple from the drive track inlet to the first storage station to replace the staple previously stored therein and now being transferred by another section of the driver blade.

In this manner, by providing one or more storage stations and corresponding staple engaging portions on the driver blade, the staples or fasteners can be successively transferred along the length of the drive track and driven into a workpiece during a series of cycles of operation of the tool, all using a pneumatic motor of a conventional construction and operating stroke. Once all of the storage stations in the drive track have been filled, each operation of the tool results in the driving of a fastener. By providing different numbers of storage stations, different amounts of clearance can be provided by the nosepiece structure. In one illustrated embodiment, the drive track and blade have a number of different width sections determined by the number of storage sections, and in another illustrated embodiment any number of storage sections can be provided using drive track and driverwidths of only two different values.

Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the drawings in which:

FIG. 1 is a side elevational view in partial section of a fastener driving tool embodying the present invention;

FIG. 2 is an enlarged sectional view of the nosepiece structure embodied in the tool shown in FIG. 1 and illustrating the drive system for the tool in a normal condition prior to operation of the tool;

FIG. 3 is a view similar to FIG. 2 illustrating the tool after a single cycle of operation;

FIG. 4 is a view similar to FIGS. 2 and 3 illustrating the nosepiece assembly at the end of a powerstroke during a second or subsequent operating cycle of the tool;

FIG. 5 is an enlarged sectional view taken along line 5--5 in FIG. 3;

FIG. 6 is a front elevational view of the nosepiece assembly shown in FIG. 4;

FIG. 7 is a sectional view taken along line 7--7 in FIG. 2;

FIG. 8 is a sectional view similar to FIGS. 2-4 but illustrating a nosepiece structure having a number of fastener storing assemblies;

FIG. 9 is a seectional view taken along line 9--9 in FIG. 8;

FIG. 10 is a fragmentary sectional view of a modification of the tool shown in FIGS. 1-7 using a driver blade of a different configuration;

FIG. 11 is an enlarged sectional view taken along line 11--11 in FIG. 10;

FIG. 12 is an enlarged sectional view taken along line 12--12 in FIG. 10;

FIG. 13 is a fragmentary sectional view of another embodiment of the nosepiece structure of another tool embodying the present invention;

FIG. 14 is an enlarged sectional view taken along line 14--14 in FIG. 13; and

FIG. 15 is an elevational view of the back of the nosepiece structure viewed in the direction of line 15--15 in FIG. 13.

Referring now more specifically to FIG. 1 of the drawings, therein is illustrated a pneumatic fastener driving tool which embodies the present invention and which is indicated generally as 10. The tool 10 is in substantial part a conventional manually manipulated and pneumatically actuated staple driving tool having a housing 12 with a rearwardly extending handle 12A affording a compressed air reservoir. When a trigger 14 is actuated to control a control valve assembly 16, pressurized air from the hollow handle 12A operates a pneumatic motor indicated generally as 18 to drive a fastener supplied by a magazine assembly indicated generally as 20 through a drive track in a nosepiece assembly indicated generally as 22 into a workpiece, such as a workpiece indicated generally as 24 (FIG. 4). The construction of the nosepiece assembly 22 and of a fastener driving blade 26 actuated by the motor 18 and slidable in the nosepiece 22 is such that the motor 18 can be of a conventional or "short" stroke construction, even though the nosepiece structure 22 is greatly elongated. This permits most of the components of the fastener driving tool 10 to be of a conventional construction used in hand tools and obviates the need for a special motor having a long stroke.

In accordance with the present invention, this is accomplished by providing a modified and lengthened driver blade 26 with separate portions for moving fasteners through different parts of the nosepiece structure 22 and by providing one or more fastener storing or retaining assemblies such as an assembly indicated generally as 28 in FIGS. 2-4. When the tool 10 is first operated, a fastener is transferred from the magazine assembly 20 to the storage assembly 28 in the nosepiece structure 22. On the next cycle of operation of the motor 18, the fastener in the storage station 28 is driven into the workpiece 24, and concurrently therewith another fastener is transferred from the magazine assembly 20 to the storage assembly 28. On all succeeding cycles of operation of the tool 10, one fastener is driven into the workpiece 24 and another fastener is transferred to the storage station or assembly 28. In this manner, fasteners from the magazine 20 are fed in increments through the nosepiece 22 to be driven into the workpiece 24 by a series of cycles of operation of the conventional pneumatic motor 18.

An indicated above, a substantial number of the components of the tool 10 can be of conventional construction. As an example, the illustrated tool 10 can comprise the pneumatically actuated tool for driving staples shown and described in detail in U.S. Pat. No. 3,638,532. As shown in this patent, the motor can comprise a cylinder 30 in which is slidably mounted a piston 32, to the lower end of which the upper end of the fastener driving blade 26 is secured. Movement of the piston 32 through an operating cycle including a power stroke and a return stroke is controlled by the control valve assembly 16 such as the comparable unit illustrated in the above-identified patent. The assembly 16 is such that the tool 10 cannot be operated unless both the trigger 14 is elevated and a safety stem 34 is moved downwardly (FIG. 1). When the lower end of a safety member or yoke 36 is moved upwardly by engagement with the workpiece 24 (FIG. 4), a pivotally mounted link 38 moves a connecting element 40 coupled to the stem 34 downwardly to depress the safety stem 34 and enable operation of the control unit 16 under the control of the manual trigger 14.

If the trigger 14 is depressed with the safety stem 34 in its lower position, a top valve (not shown) for the cylinder 18 is opened to admit pressurized fluid to the upper interior of the cylinder 18. This moves the piston 32 downwardly through a power stroke. When this piston reaches a lower position determined by engagement with a resilient bumper 42, compressed air above the piston 32 passes through a passage 44 in this piston and a passage 46 in the cylinder 30 to be accumulated within a storage return chamber 48. When the control valve assembly 16 is released, either automatically in a single stroke tool or by release of the safety member 36 or the trigger 14, compressed air above the piston 32 within the cylinder 30 is vented to the atmosphere, and the pressurized air contained within the return space 48 enters the cylinder 30 below the piston 32 through one or a number of ports 50. This pressurized air serves to restore the piston 32 to its normal condition.

The tool 10 can be arranged to drive any suitable type of fasteners such as staples or nails. In the illustrated tool 10, the magazine assembly 20 includes a pusher 52 continuously resiliently biased by a tension spring 54 to advance a strip of U-shaped staples 56 (FIG. 2) toward the nosepiece structure 22 by sliding movement supported on a rail 58, the forward end of which is carried on a shear block or member 60 rigidly secured to the housing 12 for the tool 10. The strip of staples 56 and the other components of the magazine assembly 20 are enclosed in a suitable housing 62 (FIG. 1). However, the construction of the magazine 20 can be of any of a number well known in the art and can be such as to feed not only the staples 56 but also nails, brads, and other fasteners.

The nosepiece structure 22 is, in general, formed by a front wall structure or member 64 and a rear wall structure or member 66 which are secured together and to the housing 12 and the magazine assembly 20 to define a drive track 68 having an upper portion 68A (FIG. 2) of greater width and a lower portion 68B of a lesser width. The upper end of the front wall member 64 is secured to a depending portion of the housing 12 as by a pair of machine screws 70 (FIG. 6). The upper portion of the front wall structure 64 also includes a rearwardly extending tab or wing 64A (FIG. 1) which is secured to the magazine assembly 20, as by machine screws 72. A pivot pin 74 carried on the rearwardly projecting portion 64A pivotally supports the pivotal link 38 in the operating mechanism described above for the safety stem 34.

The front wall member 64 also provides a slidable support for the safety link or operator 36. As illustrated in FIG. 6, the front wall is provided with a raised central portion 64B and two opposed pairs of projecting lugs 64C spaced from the central portion 64B. The legs of a U-shaped lower end or work engaging portion 36A of the safety operating element 36 lie between the central raised portion 64B and the lower pair of lugs 64C with a plate 76 secured in an overlying relation by a machine screw 78 so as to slidably mount the lower end of the member 36 on the front wall 64. An upper portion of the element 36 lies in the groove defined by the raised portion 64B and the left-hand one of the upper lugs 64C and is slidably mounted therein by an overlying plate 80 secured to the front wall 64 by a machine screw 82. An upper end portion 36B of the touch-trip member 36 is offset to protrude through an opening in one end of the link 38 to provide a pivotal coupling therebetween. The operator element 36 is shown in an actuated position in FIG. 6.

As set forth above, the drive track 68 including the greater width upper portion 68A and the lesser width lower portion 68B is defined by the front and back wall structures 64 and 66 in combination with portions of the structure of the tool 10, such as the block 60. The drive track 68 is primarily defined by a centrally disposed slot milled or otherwise formed in the rear surface of the front wall member 64 (see FIG. 5) and which is closed by the block 60 and the rear wall structure 66. The greater width portion 68A is defined between the slot and the facing wall of the block 60 (FIGS. 2-4) and a recess 86 formed in the front surface of the back wall member 66 (FIGS. 2-5). The narrow portion 68B of the drive slot 68 is defined by a plate portion 66A (FIGS. 2-4 and 7) which fits within the slot formed in the rear surface of the front wall member 64. In this connection, it should be noted that the portion 66A projects out of the plane of the rear wall member 66 and into the slot formed in the rear surface of the front wall member 64.

The fastener or staple storage or retaining assembly 28 is carried on the rear wall member 66 disposed within the recess 86. This assembly receives a staple 56 from the magazine assembly 20 during one stroke of the fastener driving blade 26 and transfers this staple or fastener 56 to a position in which it is driven into the workpiece 24 by the driver blade 26 during the next stroke of the pneumatic motor 18. The assembly 28 includes a pair of generally channel-shaped staple retaining and biasing members 88 and 90 (FIGS. 2-5 and 7) disposed within the recess 86 and independently biased toward the front wall of the drive track 68 by three conical compression springs 92, 94, and 96 interposed between the adjacent wall of the rear wall structure 66 and the back walls of the elements 88 and 90, respectively. The member 88 is provided to prevent upward movement of a staple 56 disposed in the assembly 28, and the member 90 is provided to rceive a staple 56 from the magazine assembly 20 on one stroke of the driver blade 26 and to transfer this staple within the drive track 68 to a position in which it will be driven into the workpiece 24 on the next cycle of operation of the tool 10.

To this end, the member 88 includes a pair of projecting and downwardly and inwardly inclined or tapered side walls 88A (FIGS. 2 and 7) spaced from each other a distance substantially equal to the separation between two spaced depending legs 56A of the U-shaped staples 56. The two cam or inclined portions 88A are spaced from each other by a somewhat channel-shaped space shown as 88B in FIG. 7.

The second retaining element 90 is also channel-shaped and includes two upstanding edge portions 90A whose upper ends 90B are inclined downwardly and inwardly toward the front wall of the drive track 68. The portions 90A, 90B of the members are spaced apart approximately the same distance as the depending legs 56A of the staple 56 to define an intervening channel or space indicated as 90C (FIG. 7).

To provide means for setting the normal position of the elements 88, 90 of the storage assembly 28 and to provide means for pre-assembling the components of the assembly 28 on the wall structure 66, the member 88 is provided with two outwardly projecting tabs 88C (FIG. 7), and the member 90 is provided with two pairs of opposed tabs 90D. The tabs 88C and 90D are disposed within extensions 86A of the recess 86 in the back wall member 66. Two thin spacers or plates 98 (one of which is illustrated in FIG. 7) are secured by machine screws 100 to the inner wall surface of the back wall structure 66 on opposite sides of the recess 86 so as to overlie the ears or lugs 88C and 90D on the two members 88 and 90. The plates 98 secure the members 88 and 90 in their desired normal position against the resilient bias provided by the compression springs 88, 94, and 96. The use of the plates 98 permits the retaining assembly 28 to be assembled on the back wall structure 66 as an integral subassembly.

This subassembly is then secured to the front wall structure 64 by placing the structure 66 in the position shown, for example, in FIG. 2, and securing the wall sections 66 and 64 together by machine screws passing through a plurality of openings 102 (FIG. 7) in the rear wall structure 66, the openings 102 also passing through the spacers or retaining plates 98. The back surface of the front wall structure 64 is relieved to accommodate the heads of the fasteners 100, if necessary. The normal position of the elements 88 and 90 in the assembly 28 relative to the drive track 68 is illustrated in FIG. 2 of the drawings.

The lower end of the driver blade 26 is slidably received within the drive track 68 and is provided with separate staple or fastener engaging sections of a stepped configuration. More specifically, the driver blade 26 includes a first step or fastener engaging surface 26A (FIG. 2) of a width approximately equal to the width of a crown portion 56B of the U-shaped staple 56. The length of the crown engaging surface 26A in a direction perpendicular to the plane of the drawing in FIG. 2 is somewhat less than the width of the spaces or channels 88B, 90C on the elements 88 and 90. The thickness of the driver blade 26 above the step or contact engaging surface 26A is approximately equal to the width of the wide portion 68A of the drive track 68 or twice the width of one of the staples 56. In the normal position of the tool 10 or the pneumatic motor 18, the contact engaging surface 26A is spaced slightly above the crown 56B of the single staple 56 fed into the wide portion 68A of the drive track 68 by the magazine assembly 20 through a staple receiving opening indicated generally as 104. This opening 104 is defined by a clearance between the block 60, the housing 12 for the tool 10, and the housing 62 for the staple magazine 20 in the usual manner. The position of the staple 56 which is resiliently biased to the right (FIG. 2) by the pusher 52 is set by engagement of the staple legs 56A and the staple crown 56B with a portion 26B of the staple driver or staple driving blade 26.

The portion 26B of the driver blade 26 terminates at its lower end in a lower staple engaging surface indicated as 26C. The length of the portion 26B is such as to extend from the step or crown engaging portion 26A to a point slightly above the lower edge of the member 88 in the storage assembly 28. The width of the portion 26B of the blade 26 is approximately equal to the width of the crown 56B of the staple 56 which is also substantially equal, considering clearances, to the width of the narrow portion 68B of the drive track 68. The length of the surface 26C and also of the portion 26B in a direction perpendicular to the sheet in FIG. 2 is substantially equal to the corresponding dimension of the drive track 68 which, in turn, is substantially equal to the length of the crown 56B measured in a direction perpendicular to the plane of the sheet in FIG. 2.

When the tool 10 is to be operated, a strip of staples 56 is placed in the magazine assembly 20, and the resiliently biased pusher 52 advances the strip of staples 56 to the right so that the first staple 56 is disposed in the position shown in FIG. 2 of the drawings which is set by engagement of this first staple 56 with the adjacent side surface of the driver blade portion 26B. In this position, the crown 56B of the first staple underlies the crown engaging portion 26A on the driver blade 26. The tool 10 is then disposed on the workpiece 24 so that a staple discharging opening 68C from the drive track 68 is disposed immediately adjacent or against the workpiece 24, and the U-shaped portion 36A of the safety link 36 engages the workpiece 24 to move the safety link or operator 36 upwardly. As set forth above, this partially enables the control valve assembly 16. The operator then actuates the trigger 14 so that compressed air is supplied to the interior of the cylinder 30 above the piston 32 to initiate downward movement of this piston and the connected driver blade 26.

During the first increment of downward movement, the surface 26A engages the crown 56B of the first staple 56 in the wide portion 68A of the drive track 68 and severs this staple from the remainder of the staple strip. During this movement of the driver blade 26, the next staple 56 is not permitted to enter the drive track 68 through the opening 104 because it bears against the upper portion of the driver blade 26.

Continuing downward movement of the driver blade 26 moves the lower or free ends of the staple legs 56A into engagement with the downwardly inclined walls 88A on the retaining member 88 so that this member is cammed or displaced to the left in FIG. 2 against the bias of the compression spring 92 and held in this displaced position as the staple legs 56A pass beyond and by the lower ends of the inclined surfaces 88A. The lower free ends of the staple legs 56A next contact the inclined surfaces 90B on the member 90 to displace this member to the left (FIG. 2) against the bias of the compression springs 94, 96. Thereafter, the sides of the staple legs 56A slide along the parallel surfaces on the edge portions 90A of the member 90 disposed between these surfaces and the flat rear surface of the blade portion 26B.

At the end of the normal or "short" operating stroke of the pneumatic motor 18 determined by the engagement of the piston 32 with the resilient bumper 42, the driver blade 26 is in the position illustrated in FIG. 4. In this position, the narrow portion of the blade 26 above the crown engaging surface 26A is slidably disposed between the inclined side walls 88A on the member 88. When the crown 56B has moved to the position shown in FIG. 4, the compression spring 92 moves the remaining member 88 to the right (FIG. 4) so that the lower edges of the side walls 88A overlie the crown 56B of the first staple. Thus, the member 88 provides a latch preventing upward movement of the first staple 56. At this time, the compression springs 94, 96 bias the element 90 to the right so that the staple legs 56A are held against the rear surface of the driver blade portion 26B in the position shown in FIG. 4. The lower driving surface 26C of the driver blade is flush with or projects slightly beyond the opening 68C at the lower end of the narrow portion 68B of the drive track but does not drive a staple 56 inasmuch as no staples have been provided as yet to this portion of the drive track 68.

When the control valve assembly 16 is released, the piston 32 is elevated to its illustrated normal position shown in FIG. 1 in the manner described above. The staple 56 remains in the position shown in FIG. 4 even though this staple is biased against the upwardly moving blade portion 26B because of the detent provided by the lower edges of the side walls 88A on the member 88. When the lower end of the driver blade portion 26B clears or passes upwardly beyond the crown 56B of the staple in the storage means 28, the compression springs 94, 96 move the member 90 to the right to the position shown in FIG. 3 so that the crown 56B of the staple 56 is moved from beneath the lower edge of the member 88, and the edge surfaces of the staple 56 are biased against the front wall of the drive track 68 defined by the rear wall of the front wall structure 64. At substantially the same time, the surface 26A clears the crown 56B of the next staple in the strip of staples in the magazine assembly 20, and an additional staple 56 is moved into the wide portion 68A of the drive track 68 beneath the crown engaging surface 26A on the driver blade 26, as illustrated in FIG. 3.

Thus, the second staple to be driven is now biased against the driver blade portion 26B with its corwn 56B underlying the driver blade surface 26A, and the first staple 56 to be driven is also disposed in the wide portion 68A of the drive track 68 with its crown 56B disposed beneath the driving surface 26C at the lower end of the driver blade portion 26B. This staple 56 in the storage section 28 is removably retained in this position by the resilient bias of the compression springs 94, 96 supplied through the retaining member 90. The tool 10 remains in this condition until such time as the next cycle of operation is initiated.

When the control 16 initiates the next power stroke of the pneumatic motor 18, the piston 32 and the connected driver blade 26 again move downwardly from the position shown in FIG. 2. At this time, the full width crown engaging surface 26C at the lower end of the driver blade portion 26B engages the crown portion 56B of the staple 56 held in the storage section 28 and moves the legs 56A of this staple downwardly into the narrow portion 68B of the drive track over the slight resistance of the resilient bias provided by the springs 94, 96. At the completion of the full stroke of the motor 18, the first staple 56 has been discharged from the drive track 68 through the opening 68C and driven into the workpiece 24 as illustrated in FIG. 4. At the same time, the surface 26A severs the endmost or second staple 56 from the strip thereof and moves this staple to the storage section 28 in the manner described above. Thus, at the termination of the second power stroke of the pneumatic motor 18, the components are in the position illustrated in FIG. 4.

The release of the control valve 16 causes the retraction of the piston 32 and the driver blade 26 so that the tool is then placed in the condition shown in FIG. 3 in which the third staple 56 in the strip is disposed beneath the driving surface 26A, and the secnd staple 56 is held in the storage section or assembly 28 with its crown 56B disposed beneath the driver surface 26C. Thus, on each successive operation of the tool 10, a staple supplied by the storage section 28 is driven into the workpiece 24, and an additional staple 56 is transferred from the magazine assembly 20 into the storage section or assembly 28. All of this is accomplished with a stroke of the pneumatic motor 18 that is approximately one-half of the stroke previously required for nosepiece structures of the length afforded by the illustrated nosepiece structure 22.

FIGS. 8 and 9 of the drawings illustrate a nosepiece structure 110 embodying the present invention and affording an even greater clearance than the nosepiece structure 22 but capable of being used with the pneumatic motor 18 without a change in the operating stroke thereof. In FIGS. 8 and 9 components similar or identical to the components in the embodiment shown in FIGS. 1-7 are identified by like reference numbers. In general, the nosepiece structure 110 utilizes a pair of staple storing or retaining assemblies identical to the assembly 28 and designated in FIG. 8 by the reference numbers 28 and 128 and a modified driver blade 112. Using the nosepiece structure 110, three cycles of operation of the tool 10 are required to transfer a staple 56 from the magazine 20 to the workpiece 24 because the staple 56 must pass in sequence through the two staple storing sections 28 and 128.

The nosepiece structure 110 includes a drive track indicated generally as 114 having an upper greatest width portion 114A, an intermediate lesser width portion 114B, and a lower narrowest width portion 114C. The widths of the portions 114A-114C differ from each other by dimensions generally equal to the width of the staple 56. The front and side walls of the drive track 114 are defined by the front wall member 64, and the rear wall is defined by the block 60 and the rear wall structures 66 of the two storage assemblies 28 and 128. Although the front wall structure is identified by the reference number 64, it is obvious that the length of this structure is greater than the front wall 64 in the nosepiece structure 22 because of the greater length of the nosepiece assembly 110. Further, the rear surface of the front wall structure 64 to which the back wall structure 66 is secured may be provided with steps so that when the two structures 66 carrying the assemblies 28 and 128 are secured thereto, changes in the width or thickness of the drive track portions 114B and 114C can be obtained. On the other hand, by changing the thickness of the retaining plates 98 secured to the wall structures 66, the same change in the width or thickness of the drive track sections 114B and 114C can be obtained using a planar rear surface on the front wall member 64.

The components of the nosepiece structure 110 are secured or joined together and to the housing 12 of the tool 10 in the same manner as the nosepiece structure 22. As an example, threaded fasteners or machine screws 70 extend through an upper portion of the front wall structure 64 to be threadedly received within a depending portion of the housing 12 (FIG. 9). The wall structures 66 are secured to the edge portions of the front wall structure 64 by threaded fasteners passing through openings corresponding to the openings 102 shown in FIG. 7. By using substantially identical assemblies 28 and 128 to provide the nosepiece structure 110, the inventory required to provide tools 10 with nosepieces of different lengths is reduced.

The driver blade 112 which is connected to and moved by the piston 32 in the pneumatic motor 18 is longer than the driver blade 26 by an amount approximately equal to the length of one of the rear wall structures 66 measured in its direction of elongation. The blade 112 is slidably received within the drive track 114. To provide means for moving fasteners or staples 56 from the staple receiving opening 104 along the drive track 114, the driver blade 112 includes portions of three widths or thicknesses 112A, 112B, and 112C slidable respectively, within the three different width portions 114A, 114B, and 114C of the drive track 114. Each of these portions 112A-112C differs from each other in width approximately the width of one of the staples 56. Each of the different width portions 112A-112C terminates in a staple crown engaging portion or surface 112D-112F, respectively, with the surface 112D being disposed immediately above the crown 56B on a staple fed by the magazine assembly 20, with the surface 112E disposed immediately above the crown 56B of the staple in the first storage section 28, and with the surface 112F disposed immediately above the crown 56B of a staple 56 in the second storage assembly 128. The portions 112A and 112B immediately above the crown engaging surfaces 112D and 112E are reduced in dimension in a direction perpendicular to the sheet in FIG. 8 to a value somewhat less than the spaces or channels 88B, 90C on the elements 88 and 90 so that the indicated portions of the driver blade 112 do not engage members 88 and 90. This reduction is illustrated in FIG. 9.

When the tool 10 containing the nosepiece structure 110 is placed against the workpiece 24 to elevate the safety operator 36, the operation of the trigger 14 to actuate the motor through its first power stroke moves the blade 112 downwardly so that the surface 112D moves the first staple 56 from the position illustrated in FIG. 5 to be stored in the first storage assembly 28. When the blade 112 is retracted, the element 88 in the assembly 28 prevents return movement of the staple 56. Thus, when the middle width portion 112B of the blade 112 clears the staple 56 in the assembly 28, the element 90 in this assembly shifts the first staple 56 into engagement with the portion 112C of the blade 112 beneath the crown engaging surface 112E.

When the pneumatic motor 18 is next operated, the surface 112D moves the second staple 56 into the first storage section 28, and the surface 112E moves the first staple into the storage section 128. When the driver blade 112 is retracted at the end of this second stroke, the element 90 in the assembly 28 shifts the second staple against the blade portion 112C with its crown 56B beneath the surface 112E. The element 90 in the assembly 128 shifts the first staple against the front wall of the drive track 114 beneath the crown engaging surface 112F.

When the tool 10 is operated for the third time, the surface 112D moves the third staple 56 from the strip into the first storage section 28, the surface 112E moves the second staple from the storage assembly 28 into the storage assembly 128, and the surface 112F engages the crown 56B of the first staple 56 to drive this staple through the narrow width drive track portion 114C into the workpiece 24. When the blade 112 is retracted, the second staple 56 from the magazine is moved under the surface 112F, the third staple 56 from the magazine is fed beneath the surface 112E, and the fourth staple 56 from the strip is advanced through the opening 104 into the drive track 114 to abut the driver blade portion 112B with its crown 56B disposed beneath the surface 112D. Thereafter, each actuation of the tool 10 drives a staple 56 into the workpiece 24 and transfers staples 56 between the magazine assembly 20 and the storage sections 28 and 128.

FIGS. 10-12 of the drawings illustrate a nosepiece structure which is indicated generally as 130 and which embodies the present invention. The nosepiece structure 130 is similar to the nosepiece structures 22 and 110 described above and can use fasteners such as the staples 56. However, the nosepiece structure 130 and an accompanying driver 132 can also be used with staples in which the crown portion is not planar or perpendicular to the staple legs. As an example, the nosepiece structure 130 can be used with staples having a crown portion that is pitched upwardly. The nosepiece structure 130 forms a part of the tool 10 and can be such as to include only a single storage section. The arrangement illustrated in FIGS. 10-12 is, however, designed for use with a tool having two storage sections and requiring three strokes to drive a staple in the manner of the nosepiece structure 110 shown in FIGS. 8 and 9. In FIGS. 10-12, those parts of the tool 10 that are similar to those described above are identified by like reference numbers.

In general, the nosepiece structure 130 is constructed in the same manner as the nosepiece structure or assembly 110 and is coupled or secured to the housing 12 of the tool 10 as well as to the magazine assembly 20. The constructions of the driver blade 132 and a drive track 134 in which the blade 132 is slidably mounted are modified from those shown in FIGS. 8 and 9. The blade 132 drives a staple 56 supplied from the magazine assembly 20 into a workpiece after a sequence of three driving strokes of the piston 32 in the pneumatic motor 18 to which the upper end of the driver blade 132 is connected. The nosepiece structure 130 includes two storage assemblies or stations 136 (only one of which is illustrated in FIG. 10) spaced along the drive track 134 in positions corresponding to the storage stations 28 and 128 in the nosepiece structure 110. Each of the storage stations or assemblies 136 is identical to the storage assembly 28 except for the means provided therein for preventing retrogressive movement of the staple 56.

The driver blade 132, the upper end of which is coupled to the piston 32 in the pneumatic motor 18, is formed in part with a generally U-shaped or channel-shaped configuration (FIG. 11) and includes a flat bight or base portion 132A of sectional dimensions generally corresponding to the planar dimensions of the crown portion 56B of a staple 56. Opposite edges of the upper portion of the driver blade 132 are provided with transversely projecting or upstanding legs 132B stepped to provide portions of two different heights, each one terminating in a pair of transversely aligned crown engaging shoulders 132C and 132D, respectively.

The pair of shoulders 132C (FIG. 10) are normally disposed just above the crown 56B of the staple supplied through the opening 104. The pair of shoulders 132D on the projecting edges 132B are spaced below the shoulders 132C a distance approximately equal to the stroke of the piston 32 and normally overlie the crown portion 56B of a staple stored in the assembly 136. The lower end of the planar base portion 132A of the blade 132 provides a means for transferring a staple 56 from the second storage assembly 136 (not shown) to the workpiece and is spaced below the pair of shoulders 132D a distance approximately equal to the stroke of the piston 32. Since the shoulders 132C and 132D engage the staple crown 56B adjacent its opposite ends in positions generally aligned with the staple legs 56A, the intervening center of the crown 56B need not be flat and can, for example, be upwardly dished or bowed.

The drive track 134 (FIG. 11) is primarily defined by a recess formed in the back surface of the front wall structure 64 which is closed by a portion of the housing 12, the shear block 60, and the rear wall structures 66 of the two storage assemblies 136 in the same manner as the drive tracks 68 and 114. However, the configuration of these parts is changed to provide U-shaped portions in the drive track 134 to receive the like formed parts of the driver blade 132. The rear wall structures 66 for the two storage assemblies 136 provide drive track portions of three progressively smaller widths as in the drive track 114 for the nosepiece structure 110. The length of the drive track 134 measured from the opening 104 to a staple discharging opening is around three times the length of the stroke of the pneumatic motor 18, the same as the length of the drive track 114, and longer than the length of the drive track 68 which is twice the length of the stroke of the motor 18.

Since the crown 56B of each staple 56 to be advanced through the nosepiece structure 130 is engaged at its ends in general alignment with the upper ends of the staple legs 56A, each of the storage assemblies 136 is modified so that the retaining means provided therein for preventing retrogressive movement of the staple 56 during the return stroke of the blade 132 engages the central rather than the edge portions of the staple crowns 56B. More specifically, the storage or transfer assembly 136 is identical to the assembly 28 described above except for the construction or configuration of a staple retaining element 138 (FIGS. 10 and 12). The element 138 is generally planar in configuration and includes offset opposite end portions or tabs 138A (FIG. 12) disposed within the recesses 86A and adapted to be biased against the locating plates 98 by the interposed compression spring 92 (FIG. 10). However, the retaining member 138 is provided with an upstanding central portion 138B (FIGS. 10 and 12) having an upper surface that tapers downwardly and inwardly (FIG. 10). The upstanding portion 138B is narrow enough to be freely movable within the channel spaced area disposed between the upstanding legs 132B on the driver blade 132.

Accordingly, when a strip of staples 56 is placed in the magazine assembly 20, its forward portion is disposed within the opening 104, and the first staple 56 is biased against the intermediate height portion of the two legs 132B with the staple legs 56A on this first staple disposed against the aligned edges of the intermediate height portion of the legs 132B. Thus, the crown 56B on the first staple 56 underlies the pair of shoulders 132C. When the piston 32 first moves downwardly, the shoulders 132C engage the crown portion 56B at its two opposite ends and separate this staple from the strip of remaining staples 56.

Continuing downward movement of the piston 32 moves the separated staple 56 downwardly through the widest portion of the drive track 134 so that the staple legs 56A engage the inclined surfaces 90B on the member 90 in the first storage assembly 136 and shift this member to the left against the bias of the compression springs 94, 96. These legs are then moved into a position interposed between the flat edge surface of the spaced legs 90A on the member 90 and the edges of the intermediate height portion of the legs 132B on the driver blade 132.

As the crown 56B of this staple moves into the station 136, it engages the inclined surface on the projecting portion 138B and cams the element 138 to the left (FIG. 10) against the bias of the spring 92. The legs 132B on the driver blade 132 pass by the projecting portion 138B. When the staple crown 56B moves downwardly below the lower edge of the retaining member 138, the lower edge of the projecting portion 138B snaps over the crown 56B on the first staple 56.

When the pneumatic motor 18 initiates its return movement, the bearing of the lower edge of the projecting portion 138B on the central portion of the crown 56B prevents return or retrogressive movement of this staple. As the blade 132 moves upwardly toward its normal position, the compression springs 94 and 96 act on the member 90 to transfer the first staple 56 to the right so that it bears against the base portion 132A of the driver blade 132 with the crown 56B of the first staple 56 disposed beneath the spaced shoulders 132D. At the end of the return movement of the blade 132, the second staple 56 moves into the widest portion of the drive track 134 with its crown below the spaced shoulders 132C. The tool remains in this condition until it is next operated.

At this time, the shoulders 132C transfer the second staple 56 from the strip into the illustrated assembly 136, and the shoulders 132D transfer the first staple 56 from the illustrated storage station 136 to the next subsequent station 136 (not shown) along the drive track 134 and located in an intermediate width portion of this drive track. When the driver blade 132 is retracted at the end of this second cycle of operation, the third staple 56 is moved beneath the shoulders 132C, the second staple is moved beneath the shoulders 132D, and the member 90 in the second storage station 136 (not shown) moves the first staple 56 beneath the lower end of the flat base portion 132A of the blade 132. Accordingly, on the next cycle of operation of the tool 10, the third staple from the strip is moved into the storage station 136, the second staple is moved into the lower storage station 136, and the first staple from the strip is driven through the narrow portion of the drive track 134 into the workpiece 24. Thereafter, each operation of the tool 10 results in driving a staple 56.

FIGS. 13-15 of the drawings illustrate a nosepiece structure which embodies the present invention and which is indicated generally as 140. The nosepiece structure 140 is adapted to be used with the tool 10 and is secured to both the housing 12 and the magazine assembly 20 to provide means for driving staples supplied from the assembly 20 through the opening 104 into a workpiece by operating the pneumatic motor 18 through a plurality of strokes. In the nosepiece assembly 140, a drive track 142 in the nosepiece structure 140 requires only two different widths or thicknesses regardless of the number of staple storing sections or assemblies provided along the length of the drive track 142. The illustrated nosepiece structure 140 includes a pair of fastener or staple storing assemblies 144 and 146 so that three cycles of operation of the pneumatic motor 18 are required to advance any given staple 56 from the magazine assembly 20 to a workpiece. The drive track 142 and thus a driver blade 147 coupled to the piston 32 and slidable within the drive track 142 can be formed having only two effective widths or thicknesses by forming the components of the transfer assemblies 144 and 146 of flexible resilient members.

The drive track 142 is defined by a front wall member 148 on the rear surface of which is integrally formed or secured a rear wall structure 150. The drive track 142 is primarily defined by a slot in the rear surface of the front wall 148 (FIG. 14) of sectional dimensions approximately equal to the planar dimensions of the staple crown 56B. The length of the drive track 142 measured from the opening 104 to its lower end is around three times the length of the stroke of the pneumatic motor 18. The open side of the slot in the front wall 148 is closed by a portion of the housing 12, by the shear block 60, and the rear wall structure 150 so that the greater portion of the drive track has a wide or greater width or thickness indicated at 142A (FIG. 13) approximately corresponding to the width of two staple crown portions 56B. A lower portion 142B of the drive track 142 has a width approximately equal to the width or thickness of a single staple crown 56B.

The rear wall structure 150 (FIGS. 13 and 15) includes a longitudinally extending slot shown generally as 152 that throughout a greater portion of its length is approximately equal to the width of the slot in the front wall 148. At its lower portion indicated as 152A and generally corresponding to the portion 142B of the drive track, the slot 152 is of less width than the slot or recess in the front wall 148 to provide a positive support for the staple legs 56A as they are driven into the workpiece. The slot 152 is interrupted substantially midway along its length by a bridging wall portion 150A on the back wall structure 150.

The driver blade 147 includes a base portion 147A of generally the same width and thickness as the narrow portion 142B of the drive track which extends from a staple engaging or driving surface 147B (FIG. 13) throughout its length to its point of connection to the piston 32 in the pneumatic motor 18. Superimposed on and formed integral with the base portion 147A are a pair of projecting portions 147C and 147D (FIGS. 13 and 14) which terminate in shoulders 147E and 147F, respectively, adapted to engage centrally disposed portions of the staple crowns 56B. The projecting portions 147C and 147D are adapted to move within the greater width portion 142A of the drive track, and their points of greatest thickness at the shoulders 147E and 147F are approximately equal to the width of the staple crown 56B. The shoulders 147E, 147F and the driving surface 147B are spaced apart approximately the length of the stroke of the motor 18.

As noted above, the back wall structure 150 is opened by the slot 152 substantially throughout its length. The staple storage assemblies 144 and 146 provide means for not only retaining and transferring staples 56 at spaced positions along the drive track 142 during operation of the tool but also provide means for selectively closing the back wall of the drive track 142. The assemblies 144 and 146 are carried on a generally U-shaped supporting bracket 160 so that a bight portion 160A of the member 160 is spaced from and disposed generally parallel to the back surface of the back wall structure 150. The two side walls of the U-shaped member 160 are secured to one or both of the drive track defining wall structures 148 and 150.

The staple storing assembly 144 is formed by a flexible and resilient member 162 having one end secured by a rivet 164 against the inner surface of the bight portion 160A of the supporting bracket 160. The member 162 has a width approximately equal to the width of the drive track 142 and is generally U-shaped in configuration so that an intermediate portion 162B (FIG. 13) is disposed within the slot 152 in the back wall member 150 overlying the adjacent portion of the driver blade 147. The portion 162B, in addition to guiding movement of the staple 56, provides means for transferring this staple to a position in which its crown 56B is disposed beneath the shoulder 147F on the driver blade 147.

To aid adequate guiding or positioning of the staple legs 56A within the drive track 142, the slot 152 is provided with two vertically spaced and opposed pairs of enlargements identified as 152B (FIG. 15). The web portion 162B is provided with two longitudinally spaced and opposed pairs of projections or tabs 162C which project outwardly into the recesses 152B. The member 162 is prestressed to bias the web portion 162B toward the front wall structure 148, and the engagement of the tabs 162C with the adjacent surface of the back wall structure 150 forms a stop to properly position the web portion 162B with respect to the drive track 142.

The free end of the member 162 is offset angularly away from the plane of the drive track 142 and is provided with a pair of offsets, projections, or ears 162D. The lower edges of the ears 162D are adapted to engage the staple crown 56B to provide means for preventing retrogressive movement of a staple 56 within the drive track 142. The ears 162D are spaced apart a distance slightly greater than the width of the projections 147C and 147D so that these projections can slide between these ears.

The storage assembly 146 is formed of a pair of flexible resilient members 164 and 166. The member 164 is of a width substantially equal to the width of the drive track 142 and includes an upper end portion 164A that is secured against the outer wall of the bight portion 160A of the supporting bracket 160 by a rivet 168. A free lower end portion 164B of the member 164 is disposed within the slot 152 to define a portion of the back wall of the drive track 142 and to provide means for releasably retaining a staple 56 beneath the lower end or staple engaging surface 147B of the driver blade 147.

To insure proper guiding or positioning of the staple legs 56A as they move through the portion of the drive track 142 closed by the second storage assembly 146, the slot 152 in the back wall of the back wall structure 150 includes a pair of opposed recesses or relieved portions indicated as 152C (FIG. 15). The free end portion 164B of the resilient member 164 includes a pair of outwardly projecting lugs or tabs 164C which project into the recessed portions 152C. The engagement of the tabs 164C with the adjacent surfaces of the back wall structure 150 serves as a stop to set the normal position of the web portion 164B which is prestressed or biased toward the front wall structure 148.

The member 166 provides a retaining member for preventing retrograde movement of a staple 56 located in the assembly 146. An upper free end of the flexible resilient member 166 is secured adjacent the inner wall of the bight portion 160A of the bracket 160 by the rivet 168. The lower free end of the member 166 which is of a width substantially less than the width of the member 164 is formed with a pair of offset and projecting ears or lugs 166A, the lower edges of which are adapted to engage the crown 56B of a staple in the assembly 146 to prevent return movement of this staple. The space between the lugs or ears 166A on the member 166 is slightly greater than the width of the projecting portion 147D on the driver blade 147.

To aid in positioning the free end of the retaining member 166 containing the offset ears 166A, the lower edge of the bridging portion 150A of the back wall member 150 is recessed or notched as shown at 150B (FIG. 13). The portion of the resilient member 166 containing the ears 166A extnds at least partially through the notch 150B which aids in locating this retaining means. The member 166 is prestressed to be biased against the bridging portion 150A.

When the tool 10 is to be operated using the nosepiece assembly 140, a strip of staples 56 is placed in the magazine assembly 20 so that the first staple 56 is moved through the opening 104 into the wide portion 142A of the drive track 142. In this position, the legs 56A and the crown 56B bear against the base portion 147A of the driver blade with the crown 56B disposed immediately below the shoulder 147E on the projecting portion 147C. When the tool is operated and the driver blade 147 begins to move downwardly, the shoulder 147E moves against the crown 56B of the first staple and moves this staple downwardly through the wide portion 142A of the drive track. As the lower ends of the staple legs 56A reach the storage assembly 144, the legs 56A engage and displace to the left the portion 162B of the resilient member 162. As the driver blade 147 reaches the end of its power stroke, the shoulder 147E moves the crown 56B of the first staple into engagement with the inclined edges of the ears 162D so that this element is deflected to the left and snaps back to the right so its lower edges overlie the crown 56B. The projecting portion 147C passes between the ears 162D during this movement.

When the blade 147 moves upwardly, the ears 162D engage the crown 56B of the first staple now in the storage assembly 144 to prevent its upward movement, and the web portion 162B of the resilient member 162 biases the staple legs 56A against the base portion 147A of the driver blade 147 as it is retracted. During this movement the protruding portion 147D on the driver blade passes between the legs 56A of the staple held by the member 162 until such time as the inclined surface thereof begins to cam against the crown portion 56B. This deflects the staple crown 56B and the upper portion of the resilient member 162B carrying the ears 162D to the left to permit the projecting portion 147D to clear or pass by the crown 56B of the staple 56 held in the assembly 144. As the shoulder 147F passes by the crown 56B, the web portion 162B biases these components to the right to the position shown in FIG. 13. This places the crown 56B of the first staple 56 beneath the shoulder 147F on the projecting portion 147D with the staple legs 56A pressed against the base portion 147A by the web portion 162B.

When the driver blade 147 next moves downwardly, the second staple 56 supplied through the opening 104 from the magazine assembly 20 moves downwardly through the wide portion 142A of the drive track 142 and is disposed in the first storage assembly 144 in the same manner as the first staple. During this movement, the shoulder 147F engages the crown 56B of the first staple and slides this staple downwardly within the wide portion 142A of the drive track 142 against the bias provided by the portion 162B of the resilient member 162. As this first staple moves into the second storage assembly 146, the legs 56A cam the lower portion 164B of the resilient member 164 to the left so that the staple 56 is held against the base portion 147A of the driver blade 147. During this movement the projecting portion 147D passes between the ears 166A on the resilient member 166 and moves the crown 56B on the first staple beneath the lower edges of these ears.

When the return stroke of the second cycle of the pneumatic motor 18 is initiated, the first staple 56 is held within the assembly 146 because the lower edges of the ears 166A engage the crown 56B of this staple. As the driver blade 147 approaches its normal position, the portion 164B of the resilient member 164 shifts the first staple 56 to the position shown in FIG. 13 so that its crown 56B underlies the lower end driving portion 147B on the driver blade 147. Further, as the inclined surface on the projecting portion 147D of the blade 147 engages the crown 56B of the second staple now in the first storage assembly 144, this staple and the member 162 are tipped to the left (FIG. 13) to permit the shoulder 147D to pass by the crown 56B of this staple. When the shoulder 147D has passed by the crown 56B, the portion 162B of the resilient member 162 moves the engaged second staple 56 to the position shown in FIG. 13 in which its crown 56B underlies the shoulder 147F.

On the next or third power stroke of the motor 18, the shoulder 147E moves the third staple 56 from the strip to the first storage assembly 144, and the shoulder 147F moves the second staple 56 from the strip to the second storage section 146. The lower end 147B of the blade 147 now engages the crown 56B of the first staple and moves this staple against the bias of the resilient portion 164B into the narrow portion 142B of the drive track 142 and out of this portion of the drive track into the workpiece. At the completion of the return stroke of the driver blade 147, the nosepiece structure 140 is in the condition illustrated in FIG. 13. Thereafter, each cycle of operation of the pneumatic motor 18 results in driving the staple 56 stored in the storage assembly 146 and the transfer of an additional staple from the magazine assembly 20 into the first storage assembly 144, the staple 56 therein being transferred into the storage assembly 146.

Although the present invention has been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which will fall within the spirit and scope of the principles of this invention.

Claims

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A tool for applying fasteners to a workpiece comprising

a drive track assembly defining a drive track with a fastener receiving opening and a fastener discharge opening and having fastener storage means therebetween,

a fastener driver slidable in the drive track and having separate portions for moving fasteners from the receiving opening through the storage means to the discharge opening in separate steps,

and an operating means coupled to the fastener driver and operable through separate strokes during each of which one fastener is moved from the receiving opening to the storage means and another fastener is moved from the storage means through the discharge opening to be applied to the workpiece,

said drive track assembly including at least one enlarged portion in the drive track,

and the fastener driver including a corresponding enlarged portion.

2. A tool for applying fasteners to a workpiece comprising

a power actuated fastener driver movable through a given stroke between normal and displaced positions,

a drive track structure defining a drive track with a fastener receiving opening through which fasteners are supplied to the drive track and a fastener discharge opening through which fasteners are discharged from the drive track to the workpiece, the fastener receiving opening and the fastener discharge opening being spaced from each other along the drive track a distance that is substantially an integral multiple of the given stroke and greater in value than one, said fastener driver being slidably mounted in the drive track,

and spaced fastener engaging portions on the fastener driver for advancing successive fasteners through different portions of the drive track on successive strokes of the fastener driver,

the fastener having a given first width,

and the drive track having a first portion of said given first width adjacent the fastener discharge opening and a second portion between the first portion and the fastener receiving opening with a width greater than said given first width.

3. The tool set forth in claim 2 including

retaining means in the drive track for removably retaining fasteners in the drive track between strokes of the fastener driver.

4. A tool for applying fasteners of a given first width to a workpiece comprising

a power actuated fastener driver movable through a given stroke between normal and displaced positions,

a drive track structure defining a drive track with a fastener receiving opening through which fasteners are supplied to the drive track and a fastener discharge opening through which fasteners are discharged from the drive track to the workpiece, the fastener receiving opening and the fastener discharge opening being spaced from each other along the drive track a distance that is substantially an integral multiple of the given stroke and greater in value than one, said fastener driver being slidably mounted in the drive track,

spaced fastener engaging portions on the fastener driver for advancing successive fasteners through different portions of the drive track on successive strokes of the fastener driver,

said drive track having a first portion of said given first width adjacent the fastener discharge opening and a second portion between the first portion and the fastener receiving opening with a width greater than said given first width,

said second portion of the drive track including portions of second and third widths greater than the first width,

and said fastener driver having portions of first, second, and third widths slidably mounted in the first, second, and third width portions of the drive track.

5. The tool set forth in claim 2 in which

said second portion of the drive track has a second width along its length,

and the fastener driver has one portion of the first width slidably mounted in the first portion of the drive track and spaced portions of said second width slidably mounted in the second portion of the drive track.

6. A tool for applying fasteners to a workpiece comprising

an elongated fastener driver operable through an operating stroke between normal and actuated positions, said driver having a fastener driving portion at one end and at least one fastener engaging transfer portion spaced above the fastener driving portion,

drive track structure defining a drive track in which is slidably mounted the fastener driver, said drive track having a lower portion slidably receiving the fastener driving portion of the fastener drive and an enlarged storage portion disposed above the lower portion and slidably receiving the transfer portion of the fastener driver,

fastener retaining means carried on the drive track structure and disposed in the enlarged storage portion of the drive track for removably retaining a fastener in the storage portion,

fastener feeding means for feeding fasteners into the drive track,

and operating means coupled to the fastener driver for actuating the fastener driver through successive strokes during which the transfer portion of the fastener driver moves fasteners into the retaining means in the storage portion and the fastener driving portion of the fastener driver moves fasteners from the storage portion into the workpiece.

7. A tool for driving elongated fasteners into a workpiece comprising

a drive track structure defining a drive track and having a fastener receiving opening and a fastener discharge opening adapted to be placed adjacent the workpiece,

fastener driving means including a fastener driver movably mounted in the drive track for movement through repeated strokes,

a magazine assembly for supplying a fastener through said receiving opening to the drive track on each stroke of the fastener driver,

and fastener storage means on the drive track structure between the fastener receiving opening and the fastener discharge opening for storing a fastener between strokes of the fastener driver whereby more than one stroke of the fastener driver is necessary to move a fastener from the fastener receiving opening to the fastener discharge opening,

the fastener storage means including a number of fastener storage assemblies spaced from each other along the drive track, each assembly adapted to store a single fastener.

8. The tool set forth in claim 7 in which

each fastener storage assembly includes deflectable means removably retaining a fastener in a position in the drive track spaced between the fastener receiving opening and the fastener discharge opening.

9. The tool set forth in claim 8 in which

the deflectable means includes a rigid fastener engaging means and resilient biasing means acting on the rigid fastener engaging means.

10. The tool set forth in claim 8 in which

the deflectable means includes flexible resilient means engaging the fastener.

11. The tool set forth in claim 7 in which

the fastener driver includes separate fastener engaging portions for moving the fastener from a position adjacent the fastener receiving opening through the storage assemblies to the fastener discharge opening.

12. A tool for driving fasteners into a workpiece comprising

a nosepiece structure defining a drive track extending from a fastener receiving portion to a fastener discharge opening with at least two drive track portions of different widths between said receiving portion and said discharge opening,

fastener driver means slidable in the drive track and having separate and spaced fastener engaging portions slidable in the different width portions of the drive track,

fastener feeding means for feeding fasteners into the drive track at the fastener receiving portion,

and operating means for moving the fastener driver means through repeated strokes in the drive track to advance a fastener from the receiving station successively through the different width portions of the drive track on successive strokes of the fastener driver means whereby movement of the fastener through the drive track from the receiving portion to the discharge opening requires more than one stroke of the fastener driver means.

13. A fastener driving tool for driving fasteners into a workpiece comprising

a nosepiece structure including spaced front and back walls joined by side walls defining a drive track, a lower end of the drive track terminating in a discharge opening and the spacing between the front and back walls being enlarged in steps above the discharge opening to provide a drive track with portions of at least two different widths,

an elongated driver element slidably mounted within the drive track with different fastener engaging portions movable in different width portions of the drive track,

a magazine assembly coupled to the nosepiece structure for feeding successive fasteners into the greatest width portion of the drive track to be engaged by the corresponding fastener engaging portion of the fastener driving element,

and means for reciprocating the fastener driving element within the drive track through a stroke substantially less than the length of the drive track to cause a fastener supplied to the drive track to be successively engaged by different fastener engaging portions on the fastener driving element and successively moved through different width portions of the drive track during successive strokes of the fastener driver element.

14. The fastener driving tool set forth in claim 13 including

biased retaining means in at least one of the different width portions of the drive track for removably retaining a fastener in said portion of the drive track between strokes of the fastener driving element.

15. The fastener driving tool set forth in claim 14 in which

one wall of the drive track is at least partially defined by a wall structure carrying a retaining means and detachably mounted on the other wall of the nosepiece structure.

16. The fastener driving tool set forth in claim 14 wherein the fastener has at least one elongated leg depending from a transverse portion and in which

the retaining means includes a first means resiliently biasing the fastener leg toward a wall of the nosepiece structure.

17. The fastener driving tool set forth in claim 16 in which

the retaining means includes a second means resiliently biased to a position overlying the transverse portion of the fastener to permit movement of the fastener retained by the retaining means in only one direction through the drive track.

18. The fastener driving tool set forth in claim 17 in which

the second means includes spaced portions overlying spaced parts on the transverse portion of the fastener.

19. The fastener driving tool set forth in claim 17 in which

the second means includes means overlying a central part of the transverse portion of the fastener.

20. A tool for applying fasteners to workpieces comprising

a nosepiece structure defining a drive track with at least two different width portions and terminating in a fastener discharge opening, the width of said portions increasing considered upwardly from a lower end of the drive track containing the discharge opening,

means for supplying fasteners adjacent an upper end of the drive track,

a fastener driver means having different width portions corresponding to and movable within the different width portions of the drive track,

fastener retaining means disposed in at least one of the different width portions of the drive track for releasably retaining a fastener,

and means coupled to the fastener driver means for moving the fastener driver means through successive strokes in the drive track to move a fastener through the drive track to the discharge opening in a series of successive strokes including more than one stroke, the fastener being retained within the drive track by the fastener retaining means between at least one pair of successive strokes.

21. The fastener applying tool set forth in claim 20 in which

the fastener retaining means includes at least two fastener retaining assemblies spaced along the drive track from each other and each disposed in a different width portion of the drive track.

22. A tool for applying to a workpiece staples having a crown portion and depending leg portions, said tool comprising: a drive track structure defining a drive track extending between a staple receiving opening through which staples are supplied to the drive track and a staple discharge opening from which staples are driven into the workpiece; a staple drive member slidably movable in said drive track; power means for moving said staple drive member in said drive track through a given drive stroke distance; the length of said drive track being substantially an integral multiple of said drive stroke distance; spaced staple engaging portions on said staple drive member for advancing staples successively through segments of said drive track, each such segment being substantially equal in length to said stroke distance; and a staple holding structure disposed along said drive track between each adjacent pair of drive track segments; said holding structure including first holding means movable transverse to the drive track and engageable with the staple leg portions for capturing an advanced staple in the drive track, and second holding means engageable with the staple crown portion for preventing retrograde movement of an advanced staple.

23. A tool as claimed in claim 22, further comprising a magazine assembly disposed adjacent said drive track structure for feeding staples through said staple receiving opening.

24. A tool as claimed in claim 22 wherein the staples have a given thickness and wherein the drive track segment adjacent the staple discharge opening is substantially of said given thickness.

25. A tool as claimed in claim 24, said drive track segments decreasing in thickness from said staple receiving opening to said staple discharge opening.

26. A tool as claimed in claim 25, said staple drive member including drive member segments extending between said staple engaging portions, each drive member segment being slidable in and substantially equal in thickness to a corresponding drive track segment.

27. A tool as claimed in claim 22, wherein said drive track structure includes a wall defining one side of the drive track, and said first and second holding means are resiliently biased toward said wall.

28. A tool as claimed in claim 27, said second holding means comprising a staple leg engaging member movable to clamp said staple leg portions against said wall.

29. A tool as claimed in claim 27 wherein each said first and second holding means includes a rigid element and a spring biasing said rigid element toward said wall, and each rigid element including a cam surface engageable by a staple in said drive track for retracting said rigid element.

30. A tool as claimed in claim 22 including a single holding structure and two drive track segments.

31. A tool as claimed in claim 22 including a plurality of N holding structures and N + 1 drive track segments.