US3261526A

US3261526A - Fastener driving apparatus

Info

Publication number: US3261526A
Application number: US355384A
Authority: US
Inventors: Edward J Novak
Original assignee: Duo Fast Corp
Current assignee: Duo Fast Corp
Priority date: 1964-03-27
Filing date: 1964-03-27
Publication date: 1966-07-19
Anticipated expiration: 1983-07-19
Also published as: DE1478894B1

Description

July 19, 1966 E. J. NovAK FASTENER DRIVING APPARATUS 5 Sheets-Sheet 1 Filed March 27, 1964 July 19, 1966 E. J. NovAK FASTENER DRIVING APPARATUS Q Irl ,y l.; M MMV 45 2 V .4 m QQN ,M v NN 7 M u Nm. @5w www om m 0% @MN www Nhw uw NQ W @n M/ 5 j A .m W a Sm D W E M ,WNW Vm @M NWN Nmxl Illl'll IIIIII July 19, 1966 E. J. NovAK FASTENER DRIVING APPARATUS 5 Sheets-Sheet 5 Filed March 27, 1964 5 Sheets-Sheet 4 E. J. NOVAK FASTENER DRIVING APPARATUS J@ EDM/A FDJ /VOM/w July 19, 1966 E. J. NovAK FASTENER DRIVING APPARATUS 5 Sheets-Sheet 5 Filed March 27, 1964 United States Patent O 3,261,526 FASTENER DRIVING APPARATUS Edward .1. Novak, Franklin Park, Ill., assigner to Fastener Corporation, Franklin Park, Ill., a corporation of Illinois Filed Mar. 27, 1954, Ser. No. 355,384 34 Claims. (Cl. 227-1) The present invention relates to ya fastener driving apparatus and, more particularly, to a portable hand tool capable of driving large lfasteners such as common nails the the li-ke Awhich are supplied 'from a continuous carrier strip.

The increasing use of automatic fastener driving tools for driving large fasteners has resulted in the requirement for a new and improved tool which is capable of driving these fasteners supplied from a carrier strip formed of strong flexible material such as plastic and the like. It is not practical to ycement the fasteners together as is commonly done in the case of smaller staples because of the interference between the heads of the nails. Thus, it is generally necessary to provide a carrier strip in which the Shanks of the nails are held in spaced apart parallel relation. The carrier strip must be relatively strong to hold these large fasteners yet flexible enough to be coiled to fit in a magazine assembly of a portable fastener driving tool.

With this in mind, it is a principal obj-ect of the present invention to provide a new and improved fastener driving tool which is capable of driving relatively large fasteners such as common nails and the like supplied from a continuous flexible carrier strip.

It is another object of the present invention to provide a new and improved fastener driving tool including means for positive positioning each successive fastener of the carrier strip in a proper orientation with the drive track of the tool for driving by the driving element.

It is another object of the present invention to provide a new and improved magazine and feed assembly for a portable fastener driving tool which is capa-ble of holding a relatively large supply of fasteners carried on a continuous flexible carrier strip and which positively indexes each successive fastener on the strip into a -feed position wherein it is then positively separated from the strip and fed into the drive track of the tool.

Another object of the present invention is the provision of a new and improved pneumatically operated magazine assembly for a fastener driving tool which is automatically actuated in selected synchronous rela-tion with the movements of the fastener driving element of the tool.

Still another object of the present invention is the provision of a new and improved Pneumatically operated magazine assembly for a fastener driving tool which prevents fring of the tool after the last fastener in the magazine has been driven.

Yet another object of the present invention is the provision of a new and improved Pneumatically operated magazine assembly for a fastener driving tool which is automatically disabled from supplying fasteners to the drive track of the tool until the lower end of the drive track is positioned against a workpiece.

Yet another object of the present invention is the provision of a new and improved magazine assembly in which new and improved means are provided for positively separating each success-ive fastener from the carrier strip prior to the feeding of the fasteners into the drive track.

The foregoing and other objects and advantages of the present invention are accomplished by the provision of a new and improved tool for driving fasteners supplied from a continuous exible carrier strip. The tool includes a reciprocal fastener driving element which is slidably disposed within a drive track having a fastener feed opening in the wall thereof. A magazine assembly is provided which includes fastener indexing means having rotatable sprocket means with fastener receiving grooves spaced around the periphery thereof. The grooves engage successive fasteners of the carrier strip to positively move and index each fastener into a feed position immediately adjacent the feed opening in the wall of the drive track. A fastener pusher is provided to sever the previously indexed fastener from the carrier strip and move the individual fastener into the drive track.

Pneumatically operated means are provided for actuating the fastener indexing means and for actuating the pusher in selected synchronous relation with the move'- ment of the fastener driving element. A pneumatic safety device is provided which prevents actuation of the tool unless the drive track is pressed against a workpiece, and additional means are provided for disabling the indexing and pusher means from operation after the last fastener in the carrier strip has been driven.

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

FIG. 1 is a sectional view of a fastener driving tool embodying the present invention and shown in a normal position;

FIG. 2 is a sectional view of the magazine and feed assembly of the fastener driving tool of FIG. 1 taken substantially along the line 2 2 in FIG. 1;

FIG. 3 is a sectional View similar to FIG. 1 showing the drive tool in its operated position;

FIG. 4 is a sectional view similar to FIG. 1 showing it after release but prior to restoration to its normal condition;

FIG. 5 is a sectional View taken along line 5 5 in FIG. l showing the fastener indexing means in its normal position;

FIG. 6 is a view similar to FIG. 5 taken along line 6 6 in FIG. 3 and showing the fastener pusher means in a retracted position;

FIG. 7 is a view similar to FIG. 5 taken along line 7 7 in FIG. 4 and showing the fastener indexing means in a disabled position; and

FIG. 8 is a perspective view of the fastener indexing'y means of the present invention.

Referring now to the drawings, there is illustrated a new and improved pneumatically operated fastener driving tool 10 which is constructed in accordance with the present invention. The tool 10 includes a main housing 12 which is preferably constructed of a strong, lightweight material such as aluminum in order that the tool can be easily manipulated by an operator. The main housing 12 includes a rearwardly extending hollow handle 14 which serves as a reservoir for compressed air supplied to the tool by a flexible hose (not shown). The forward portion of the main housing 1.2 provides a vertically disposed cylindrical chamber 16 which extends downwardly from the forward end of the handle 14. The upper end of the chamber 16 is in communication with the interior of the handle 14 by means of an enlarged opening 18l in the upper side wall of the chamber and is continually supplied with compressed air from the handle.

The chamber 16 contains a fastener driving mechanism 20 which includes a piston assembly 22 movably disposed within `a sliding sleeve 24 carried in the upper portion of the chamber. A fastener driving element 26` is secured to the lower end of the piston assembly 22 and when the tool is fired, the fastener driving element moves downwardly in guided sliding engagement within a drive track 28 formed in a nosepiece assembly 30 which is disposed at the lower depending end of the chamber 16. The drive system for the element 26 is of the general type shown and described in Wandel et al. Patent Nos. 2,979,- 725 or 3,043,272.

A magazine assembly 32 is provided in order to feed individual nails 34 into the drive trackV 28 to be driven by the tool. The nails 34 are of the headed type such as common nails and are supplied from a flexible, continu-ous carrier strip 36 of considerable length. An enlarged magazine housing 38 (FIG. 2) is provided in order to receive and contain a considerable number of the nails on the carrier strip. The magazine assembly 32 includes guide means for guiding the nails carried by the strip forwardly from the housing 38 toward the nosepiece assembly where a nail indexing means 40 (FIGS. 5-7) positively positions each successive nail into a feed position closely adjacent a feed opening in the drive track 28. Adjacent the forward end of the magazine assembly there is provided a reciprocally movable pusher 42 which engages successive nails arriving in the feed position and separates them from the strip 36 to feed them, one at a time, into the drive track 28.

In order to initiate a ring stroke of the tool for driving the nails, there is provided a manually operated valve means 44 (FIG. l) which is actuated by a trigger 46 carried on the handle 14 of the tool. A magazine operating mechanism, indicated generally as 48, is operatively associated with the valve means 44 to operate the nail indexing means and pusher 42 in a selected timed relation with the tiring stroke of the tool. The magazine operating mechanism 48 includes a movable operator piston assembly 50 which is connected to the pusher 42 and which is operatively linked with the nail indexing means 40 by means of a pawl member 52.

The operator piston assembly 50 is disposed for sliding movement within a valve cylinder 54 defined in a base member 56 which forms a central body of the magazine assembly 32. plurality of air passageways and valve chambers for pneumatically interconnecting the manually operated valve means 44, the chamber 16, the reservoir handle 14, and the p valve cylinder 54 in order that the tool can be fired and the magazine assembly 32 operated in a timedsequence there- The base member 56 is provided with a tool and prevent the ring thereof until the lower end y of the nosepiece assembly 30 is positioned against a workpiece 60.' Various operating elements of the safety device 58 are carried by the base member 56 and include a plunger-type safety valve element 62 which is slidably disposed within a passage 64 formed in the base member.

The magazine assembly 32 is also provided with automatic means for preventing the firing of the tool after the last nail has been driven, which means includes a valve member 66 that is formed at the rear end of the operator piston assembly and is operable to prevent the flow of compressed air into the valve cylinder 54 after the last nail in the magazine assembly has been driven. In conjunction with this feature, a manual reset valve means 67 is provided to reset the tool for operation after a new carrier strip of nails has been placed in the magazine assembly 32.

Referring now to the fastener driving mechanism 20, the piston assembly 22 comprises a lower piston 68, an upper piston 70 of slightly larger diameter and a central neck 72 of reduced diameter which integrally joins the upper and lower pistons into a single unit. The lower end of the piston assembly 22 is provided with an axial opening 22a for receiving the upper end of the driving element 26 `which is secured therein by a pin 74.

The lower piston 68 is slidably disposed within a cylinder liner 76 which is provided in a lower cylinder 78 `formed in the chamber 16. The lower cylinder 78 is closed at the bottom end thereof, by an end wall 80 which has a central aperture 82 in order to accommodate and guide the driving element 26 as it moves downwardly in a driving stroke. A port 84 is provided in the side Wall of the lower cylinder 78 at the lower end thereof in order to maintain atmospheric pressure within the cylinder in the region below the lower piston 68. A stop member or bumper 86 of resilient material is disposed on the lower end wall 80 of the lower cylinder to reduce the striking force on the end wall as the piston assembly 22 reaches the end of a driving stroke. An O ring 88 is disposed within an annular groove provided around the edge of the lower piston 68 to seal the piston to the internal surface of the lower cylinder liner 76.

The upper piston 70 is slidably disposed within the sleeve 24 which in turn is mounted for sliding movement within an upper cylinder 90 formed in the upper end of the chamber 16. The upper end of the upper cylinder 90 is closed by a removable cap assembly 92 which is threadedly engaged therewith, and the lower end of the cylinder 90 is in communication with the upper end of the lower cylinder 78. The lower end of the upper cylinder 90 is provided with a narrow band portion 94 having a slightly reduced diameter and lined with a liner 96 which extends upwardly above an annular shoulder 98 formed at the upper end of the reduced diameter band portion 94. An O ring 100 is disposed at the upper end of the liner 96 to provide a seal between the internal wall of the upper cylinder 90 and a portion 24a of the outer surface of the sliding sleeve 24. A port 102 is provided in the side wall of the upper cylinder 90, which port is aligned with a port 96a formed in the liner 96 to allow atmospheric air to enter an annular recess 104 defined between the internal surface of the liner 96 and the band surface 24a of the sleeve 24 immediately below the O ring 100.

The sliding sleeve 24 is constructed with a thickened wall portion at the lower end thereof forming a relatively narrow lower band portion 106 which slides within the liner 96, and an O ring 108 is disposed within an annular recess defined in the band portion 106 to provide an air tight seal between the band and the liner. Immediately above the band portion 106, the sleeve 24 is provided with a slightly thinner wall portion of relatively narrow width dening the narrow bandv portion 24a and having an outer surface which is sealingly engaged with the O ring 100 as previously described. Immediately above the portion 24a, the sleeve 24 is provided` with an enlarged annular ring or'piston portion 112, the outer surface of which is slidably engaged with the interior wall of the upper cylinder 90. Above the annular ring 112, the sleeve 24 comprises a relatively thin walled portion 114, the upper edge of which is engageable with a resilient main valve element 116 in a main exhaust valve assembly 118. The exhaust valve assembly 118 is carried on the cap assembly 92 and controls the connection of the upper portion of the interior of the sleeve 24 to the atmosphere.

The internal diameter of the sleeve 24 is constant in order to accommodate the sliding movement of the upper piston 70 during the driving and return-strokes of the piston assembly 22 and an O ring 120 is disposed within an annular groove provided in the edge of the upper piston 70 to provide a seal between the piston and the adjacent wall surface of the sleeve 24.

lWhen the sleeve 24 is in its upper position shown in FIG. l of the drawings, the upper end thereof is in contact with the resilient main valve elementJ 116, and compressed air within the upper cylinder 90 cannot enter the interior of the sleeve to `drive the piston assembly 22 downwardly. In order to tire the tool, the sleeve 24 is 90. As the sleeve moves downwardly, the exhaust valve assembly 118 is closed, and the top end of the sleeve moves away from the valve 116 to allow compressed air within the upper cylinder 90 to ilow rapidly into the upper interior of the sleeve and drive the piston assembly 22 and the fastener driving element 26 downwardly to the position shown in FIG. 3.

Immediately above the shoulder 122, between the upper cylinder 90 and lower cylinder 78, a port 124 is provided to allow compressed air to How into and out of an annular central space 126 which encompasses portions of both the lower end of the upper cylinder and the upper end of the lower cylinder. More specically, the central annular space 126 comprises a moving annular space surrounding the central neck 72 of the piston assembly 22 beneath the upper piston 70 and above the lower piston 68.

When compressed air is supplied to the central space 126 through the port 124, pressure acts on the lower surface of the piston 70 to move the piston assembly 22 upwardly within the sleeve 24- until it reaches the position of FIG. l with the upper surface of the upper piston 7i) engaging a lower surface 118:1 of the main valve assembly 118. The upper end of the piston assembly 22 is provided with an axially disposed recess 22h to accommodate a depending portion of the valve assembly 118 when the piston assembly is in the position shown in FIG. 1.

Compressed air within the central space 126 also causes the sleeve 24 to move upwardly to the position shown in FIG. l since the upper surfaces on the sleeve 24 exposed to the compressed air in the upper cylinder 90 are smaller in area than the lower surfaces of the sleeve subject to the air pressure within the central space 126. The exhaust valve assembly, which can be of the type shown in the above-identified patents, allows the entrapped air above the upper piston 70 to be exhausted to the atmosphere as the piston moves upwardly in the sleeve on its return Stroke and also operates to prevent the air in the upper end of the upper cylinder 90 from being exhausted to the atmosphere during a driving stroke of the piston when the sleeve 24 moves downwardly away from the resilient valve element 116.

When the tool is fired, the port 124 is connected to the atmosphere to allow the pressure within the annular central space 126 to drop. As this occurs, the upper end of the sleeve 24 moves downwardly away from the valve element 116 to allow compressed air to rapidly fill the upper end of the sleeve and drive the piston assembly 22 and driving element 26 rapidly downward in a driving stroke. After a ring stroke, the central space 126 is immediately repressurized with compressed air from the handle 14 through the port 124. When this happens, the sleeve 24 moves upwardly until the upper end thereof seats against the resilient valve element 116 closing oif the upper end of the sleeve. Simultaneously with the upward movement of the sleeve 24, the air pressure within the annular central space 126 causes the piston assembly 22 to move upwardly on its return stroke and the exhaust valve assembly 118 opens to allow the air entrapped within the sleeve above the piston 70 to be exhausted to the atmosphere.

The space surrounding the surface 24a of the sleeve immediately above the O-ring 100 is subject to the pressure 0f the air within the upper cylinder 90 while the space immediately below the O-ring 161) is always subject to atmospheric pressure because of the ports 102 and 96u. This compresses the O-ring 100 downwardly against the top end of the liner 96 and provides a tight seal between the sleeve and the walls of the upper cylinder 90 and prevents any loss of compressed air from the cylinder to the atmosphere.

The magazine assembly 32 and its associated assemblies and parts provide means for holding a supply of fasteners or nails 34 and for feeding the nails, one at a time, into the drive track 28 of the nosepiece assembly 30 in proper timed relationship with the movements of the driving element 26. When the tool is l'lred by manual actuation of the trigger 46, a nail is driven, and, as the driving element moves upwardly on its return stroke, another nail is automatically positioned in the drive track in preparation for the next firing stroke.

The forward end of the magazine assembly 32 is positioned to communicate with a feed opening 128y provided in the rear wall of the drive track 28, The feed opening 128 is dimensioned t0 be slightly wider than the Shanks Vof the nails 34 and is provided with an enlarged head portion 128a at its upper end to accommodate the heads of the nails as they pass into the drive track. The enlarged portion 12841 of the opening slidably accommodates a nail head engaging tip 42a formed at the forward end of an upper leg 32b on the U-shaped pusher 42. The feed opening 128 is also provided with an enlarged opening 128b adjacent its lower end to slidably accommodate a similar tip 42C formed at the forward end of a lower leg 42d on the pusher 42.

A supply of the nails 34 is provided by the flexible carrier strip 36 which is coiled within the magazine housing 38. This housing is of generally cylindrical conguration and is disposed at the rearward end of the magazine assembly 32. The housing 38 is detachably secured at its forward face 38a (FIG. 2) to a rear end face 56a of the body member 56 and comprises a bottom wall 129 for supporting the nails, a circular side wall 13G having a forward opening 131m abutting the face 56a, and a top wall 131 which is removable from the circular side wall to facilitate the loading and Icoiling of the carrier strip of nails in the housing. In order to guide the nails 34 from the rear housing 38y into the feed opening 128 of the nosepiece assembly 30, there is provided a guide track 132 (FIG. 2) which extends forwardly from the opening 13th: of the housing 38 to communicate with the feed opening of the nosepiece assembly. The guide track includes a straight portion 133, a curved portion 134 adjacent the indexing means 40, an-d a short forward end portion 135 (FIG. 7) which communicates directly with the feed opening 128. The inner surface of the guide track 132 is dened by the left-hand edges of the body member 56 (FIG. 2) and by a pair of upper and

lower guide plates

136 and 138, respectively, which extend forwardly of the body member S6 to abut a rear face 30a of the nosepiece assembly 30. The outer surface of the guide track 132 is formed by a forward side wall member 140 which has an inner face 14th: disposed in spaced relation to the left-hand edge of the

plates

136 and 138. The guide track 132 is slightly greater in width than the diameter of the Shanks of the nails 34; and the heads of the nails are vsupported on the upper surfaces 0f the wall member 1419, the upper plate 136, and the body member 56 as the nails move forwardly along the track from the magazine housing 38.

In order to move the nails 34 of the carrier strip 36 forwardly along the guide track 132 to position successive nails in the strip in a feed position (FIG. `6) immediately adjacent the feed opening 128, the indexing means 40 is provided with a pair of upper Iand lower

rotating sprockets

142 and 144, respectively. The sprockets are joined together by a central cylindrical spacer 146, and the assembly is provided with a central shaft 148 the upper end of which is journaled in the plate 136 and the lower end of which is journaled in the lower plate 138. The indexing means 40 is rotatable about a central vertical axis 148a in a clockwise direction as indicated by the arrows in FIGS. 2, 5, 6, 7, and 8 to move the nails from the straight lportion 133 of the guide track 132 around the curved portion 134 into the feed position of FIG. 6 within the short forward end portion 135 of the track.

Each of the

sprockets

142 and 144 are provided with teeth around the periphery thereof which form a plurality of spaced apart nail shank receiving grooves 150. 'Ihe grooves 150 are spaced so that as the indexing means 40 is rotated, successive nails 34 in the carrier strip 36 are picked up and moved around the curved portion 134 of the guide track 132 into the feed position. This rotating -action of the indexing means moves the string of nails in the carrier strip 36 out of the .magazine housing 38 forwardly along the guide track 132, and positively indexes each successive nail on the strip into the feed position shown in FIG. 6. As each successive nail 34 reaches the feed position, rotation of the indexing means is stopped because the shank of the nail as it reaches the feed position engages a side wall 135a of the short forward portion 135 of the guide track.

After a nail 34 has 'been positively indexed by the indexing means 40 into the feed position, the pusher 42 moves forwardly to its full forward position shown in FIGS. 1, 2, -and 5. During the forward movement of the pusher 42, the upper tip 42a thereof engages the nail head; and the lower tip 42e engages the lower end of the nail shank to snap the nail away from the carrier strip 36 and move it through the feed opening 128 into the drive track 28. When the head -of the nail clears the feed opening 128, the nail then drops downwardly from the upper posi-tion in the drive track shown in phantom in FIG. 1 to the lower position shown in solid outline. To prevent the nail from dropping completely out of the drive track, a spring retaining means 151 is provided on the nosepiece assembly 30 which means includes la spring member 152 having a nail head engaging portion normally extending into the drive track to retain the nail in the track until lit is driven. As the driving element 26 moves downwardly on a driving stroke, the spring -member 152 -is cammed outwardly as `shown in FIG. 3 to allow the nail to be driven.

The forward movement of the pusher 42 is limited by engagement `of lforwardly facing shoulders 42e on the legs 42a and 42C with the rear face 30a of the nosepiece assembly 30. When the pusher is in its forward position with the shoulders 42e engaging the rear face 30a of the nosepiece assembly, the forward ends of the tips 42a and 42e are positioned tangent to the rearwardmost wall portion (FIG. 1) of the drive track 28 so that a nail which has been moved into the drive track can drop freely downward -until the head thereof engages the spring retaining member 152.

The pusher 42 includes a central or bight portion 42f integrally formed with the upper and lower legs 42h and 42d. As the pusher moves forwardly to feed a nail into the drive track 28 and subsequently is withdrawn to the position shown in FIGS. 6, and 7, the bight portion 423c is slidable within

enlarged slots

136a and 138a provided in the

guide plates

136 and 138, respectively. The bight 42)c `of the pusher is tightly secured on a threaded shank 50a disposed at the forward end of the operator piston assembly 50 by a nut 153.

The operator piston assembly 50 includes a rst cylindrical stern portion 154 disposed adjacent the end shank 50a and terminating in an annular shoulder 155. Rearwardly from the s-houlder 155, there is provided. a second larger cylindrical stem yportion 156 which terminates in another annular shoulder 157. Rearwardly of the shoulder 157, there is provided a front piston 158 having an O ring 159 disposed in an annular recess around the periphery thereof. Adjacent the valve means 66 at the rear end of the operator piston assembly 50, there is provided a rear piston portion 160 having an O ring 161 disposed in an annular recess around the periphery thereof. The front piston 158 is slightly smaller in diameter than the rear piston 160 and the two are interconnected by an integral rod-like portion 162 of reduced diameter to provide an annular space 163 defined within the valve cylinder 54 between the front and rear pistons of the operator piston assembly.

The front piston 158 is slidably disposed within a forward portion 164 of the valve cylinder 54, which portion is slightly smaller in diameter than a rear portion 165 of the valve cylinder in which the rear piston is slidably mounted. The valve cylinder 54 is provided with a pair of wall ports 166 and 167 which are positioned in the wall of the Icylinder in the central area thereof adjacent the juncture of the forward portion 164 and the rear portion of the cylinder. The upper port 166 is in communication with the manually operated valve means 44, and the lower port 167 `is in communication with the manual reset valve means 67.

The pawl member 52 operatively interconnects the operator piston assembly 50 with the nail indexing means 40. The pawl (FIG. l8) is comprised of an L-shaped spring member having both a short mounting leg 168 which is disposed for sliding movement on the rst stem portion 154 of 'the operator piston assembly 50 and a longer operating leg 169 which is deflectable outwardly during the later portion of the forward travel of the operator piston. The forward end of the leg 169 is provided with a vertically extending groove engaging member 1-70 which is engageable within the grooves 150 of the upper and

lower sprockets

142 and 144 to rotate the sprockets in a clockwise direction upon rearward movement of the pawl.

During the later portions of the forward travel of the operator piston assembly 50, the rear face of the mounting leg 168 of the pawl 52 is positioned against the annular shoulder 155 on the piston assem'bly and the pawl then moves forwardly with the assembly. As the forward travel proceeds, the groove engaging member 170 at the forward end of the pawl is deflected outwardly by camming action with the teeth of

sprockets

142 and 144. In order to insure that the

indexing sprockets

142 and 144 are not rotated in counterclockwise direction by the camming action with the forwardly moving member 170, there is provided a resilient back lash pawl 171 (FIG. 2), the forward end of which engages successive nails 34 in the carrier strip 36 and prevents rearward movement of the strip while allowing forward movement thereof. Since the nails of the strip are engaged between the teeth of the spr-ockets, the sprockets cannot be rotated in a counterclockwise direction unless the -pawl 171 is disengaged from the nails and hence possi'ble back-lash during forward movement of the pawl 52 is prevented. After the member 170 moves far enough forwardly to clear two aligned teeth on the sprockets, it springs inwardly into engagement with the adjacent grooves 150 in these sprockets. When the operator piston assembly 50 starts to travel rearwardly, the pawl 52 remains stationary while the stem portion 154 slides through the mounting leg 168 until this leg abuts the rear face `of the 'bight portion 42)c of the pusher 42. Upon Vfurther rearward travel of the operator piston assembly 50, the pawl 52 moves rearwardly therewith and the member 170, which is engaged with the

sprockets

142 and 144, causes a clockwise rotation of the index means 40 to positively index the next nail 36 into the feeding position shown in FIG. 6.

Upon forward travel Iof the operator piston assembly 50 during the next feeding stroke, the stern portion 154 moves forwardly through the leg 168 of the pawl 52 until the shoulder 155 engages the leg. Further forward travel of the operator piston assembly 50 causes the pawl 52 to move forwardly so that the groove engaging member 170 at the forward end of the pawl will engage the next selected groove 150 on the

sprockets

142 and 144. When the operator piston assembly 50 next moves rearwardly, the index means 40 advances the next nail 34 in the carrier strip 36 into the feeding position.

By means of the lost motion connection between the operator piston assembly 50 and the pawl 52, the pusher 42 is moved through a considerably greater distance than the pawl, which only moves to rotate the indexing means 4l? an lamount neces-sary to advance each successive nail from the strip into the feeding position. Additionally, the lost motion mechanism allows the pusher 42 to move rearwardly for a short distance before the pawl 52 starts to move engaging the sprocket teeth to rotate the indexing means 40. This delay in the commencement of the rotation of the indexing means allows the forward tips 42a and 42e of the pusher to be clear of the forward portion of the guide track 135 so as not to interfere with the next successive nail 34 which is being fed into the feed position by the indexing means. The amount of rotation of the

sprockets

142 and 144 between successive forward strokes of the pusher 42, if measured at the pitch circle of the sprockets, is exactly equal to the spacing between the centers Vof successive nails 34 in the carrier strip 36, so that during each successive rotary movement of the sprockets, a new nail is carried Ainto the curved section 134 of the guide track 132. It should be noted that the outer surface of the curved. portion 134 is substantially coextensive with the portion of the outer periphery of the sprockets defined 4by the outer ends of the teeth. The inner surface of the curved portion 134 is substantially coextensive with a portion of the root circumference of the sprockets measured at the bottom of the grooves 150.

The manual valve means 44 controls the manual operation of the tool 10 and includes a hollow tubular member 180 which communicates with the interior lof the handle 14 and which is supported for vertical sliding movement -in a gland fitting 182 carried on the bottom wall of the handle 14. The lower end of the member 180 is slidably supported in the vertical slideway 184 defined in the body member 56 of the magazine assembly 32. An enlarged portion 186 at the lower end of the member 180 is provided with a downwardly facing conical valve surface 188 -at its lower end and an upwardly facing annular conical valve surface 190 at its upper end. Immediately above the upper valve surface 190, the tubular member is provided with a reduced diameter portion 192 which provides an annular space 195 between this portion and the walls of the slideway 184.

'Ihe enlarged end portion 186 -of the tubular member 180 is disposed for sliding movement within a trigger valve chamber 194 formed in the body member 56, the upper end of the chamber 194 being in communication with the lower end of the slideway 184. The upper end of the valve chamber 194 is also provided with an O ring 196 which encircles the opening to the slideway 184 and forms an upper valve seat cooperating with the upper valve surface 190 on the member 186. The lower end. of the valve chamber 194 is provided with an O ring 198 which encircles a bottom port 200 and forms a lower valve seat cooperating with the lower valve surface 188.

The tubular member 180 is vertically movable between an upper position (FIG. l) wherein the upper valve surface 190 is seated against the upper O ring valve seat 196 and a lower position (FIG. 3) wherein the lower valve surface 188 is seated against the lower O ring valve seat 198. The trigger 46 is pivotally mounted on a pin 202 which is supported on a bracket 284 formed on the underside of the handle 14. The trigger includes a portion 206 disposed forwardly of the pivot pin which is provided with a forwardly opening slot 208 in which is disposed a round lug or pin 210 carried on the tubular member 180. The trigger extends rearwardly of the pivot pin 202 and is biased downwardly to the position of FIG. 1 by a com- .pression spring 212. When the trigger is not being depressed by an operator, the forward portion 206 is biased upwardly by the compression spring 212 to maintain the tubular member 180 in the upper position of FIG. 1 with the upper valve surface 190 seated against the upper O yring 196 in the valve chamber 194. In this position, compressed air from the handle 14 flows freely through the tubular member 180 into the valve chamber 194. When the trigger 46 is actuated by an operator, the biasing spring 212 is compressed, and the forward end 206 moves the tubular member downwardly to the position of FIG. 3 in which the lower valve surface 188 seats against the lower O ring 198. In this position, compressed air cannot flow directly into the chamber 194 from the bottom end of the tubular member but can iiow out through the bottom port 200. Furthermore, in this position any air within the chamber 194 flows upwardly into the annular space 195 within the slideway 184 since the upper valve surface is not seated against the upper O ring valve seat 196. When the trigger 46 is released, the tubular member 180 moves back to the upper position shown in FIG. 1 under the influence of the biasing force supplied by the compression spring 212.

Directly 'beneath the lower end of the valve chamber 194 and in communication therewith through the bottom port 200, there is provided a passage 214, one end of which communicates with the lower end of the safety valve passage 64. The passage 214 is also in communication with 'the annular space 163 dened in the piston valve cylinder 54 by means of the port 166. Thus, regardless of the position of the tubular member 180, compressed air from the handle is continuously supplied. to the passage 214 and consequently to the Iannular space 163 directly from the lower end of the tubular member 180.

Above the passage 214 and parallel thereto, there is provided a passage 216 which extends between the side wall of the valve chamber 194 andthe left-hand side (as viewed in the drawings) of the safety valve passage 64. Aligned with the passage 216 and extending rearwardly from the right-hand side (FIGS. l, 3, and 4) of the safety valve passage A64, there is provided a short passage 218. The rear end of the passage 218 is in communication with a vertically extending passage 220, the lower end of which is in communication with the rear end of the cylinder 165 through a centrally disposed end port 222. The upper end of the vertical passage 220 is in communication with a horizontally extending passage 224 which communicates with another vertical passage 226, and the upper end of this passage is in communication with the port 124 in the side wall of the chamber 16.

The annular space 195 within the slideway 184 cornmunicates with one end of a ball valve chamber 228 formed in the body member 56 through a passage 230. The other end of the ball valve chamber 228 is vented to the atmosphere through an end port 232 which is encircled by an O ring valve seat 234 disposed at one end of the chamber. A ball element 236 is disposed within the chamber and is movable to seat against the O ring 234 to close the exhaust port 232.

In order to prevent the ball 236 from closing the exhaust port 232, there is provided a ball valve operator 238 which is centrally pivoted on a pin 240 carried by `a bracket 242 formed on the upper guide plate 136. The upper end of the operator 238 is provided with a ball engaging stem 244 for holding the ball in an unseated position whenever the lower end of the operator is moved forwardly to the position shown in FIG. l by engagement with the shoulder 157 on the operator piston assembly 50. When the operator piston assembly 50 moves to the rear as shown in FIGS. 2 and 3, the shoulder 157 no longer engages the operator 238 and the ball 236 is then free to seat against the O ring 234 and shut the exhaust port 232. It should be noted that the shoulder 157 is positioned on the operator piston assembly 50 so that `it will only engage the operator 238 during the final portion of the forward travel of the assembly. For example, the shoulder may be positioned on the assembly so that it will not engage the operator until the final 1/16 of its forward stroke. This provides an additional safety feature in that should a nail become jammed in the feed position preventing the full forward travel of the pusher 42 the operator 238 will not be engaged by the shoulder 157 and the tool will not fire when the trigger is depressed because the ball 236 will not be held off the seat 234 by the stem 244 of the operator 238. This is a desirable safety feature which prevents the jamming of nails in the feed slot 128 or the drive track 2S which might occur if the tool were tired when a nail was misaligned or not properly positioned in the drive track.

The automatic safety devi-ce 58 includes a vertically movable sensing rod 250 having -its lower end normally disposed adjacent to and extending below the lower end of the nosepiece assembly 30 as shown in FIG. 1 so that when the nosepiece assembly of the tool is positioned against .a workpiece 60 the rod will move upwardly relative thereto as shown in FIG. 3. The upper end of the sensing rod 250 .is connected to the forward end of a lever 252 which is p-ivotally mounted about a centrally disposed axis on a pivot pin 254 carried on a bracket 256 formed on the housing. The rear end of the lever 252 is connected to the upper end of the valve element 62 by an end 'slot 25211 which receives a pin 258 on the valve element. The rear .portion of the lever 252 is biased upwardly by compressed air acting upwardly on the lower end of the valve element 62 and additionally there is provided a com- .pression spring 260 to bias the rear end of the lever upwardly when there is no air pressure acting on the lower end of the valve element 62. Thus, the valve element 62 is normally biased to a safe position as shown in FIG. 1 at all times until the sensin-g rod 250 is moved upwardly. When the nosepiece assembly 30 is pressed against a workpiece 60, the sensing rod 250 also engages the workpiece and moves upwardly to move the valve element 62 downwardly to a fire position shown in FIG. 3.

-When the valve element 62 is in `its upper or safe position shown in FIG. 1, communication between the .

passages

216 and 218 is interrupted by the valve element. However, communication between the passage 214 and the passage 218 is established through an end bore 62a and side opening 62b in the valve element 62. When the valve element 62 is in its lower or fire position shown in FIG. 3, communication is established between the passage 216 and the passage 218 through an annular groove 62C formed in the valve element 62 and communication between the passage 218 and passage 214 is interrupted.

' Provision is made to vent the annular space 163 Within the valve cylinder 54 by means'of the manual reset valve 67. The reset valve includes a conical valve surface 67a formed at the upper end thereof which is normally seated on an O ring valve seat 261 disposed -in the lower end of a reset valve chamber 262. The upper end of the chamber 262 is in communication with the annular space 163 through the bottom port 167 in the valve cylinder 54, and the lower end of the chamber 262 is vented to the atmosphere by an exhaust port 264. The reset valve 67 includes a thin downwardly extending stern 67b having a button 67e` on the lower end thereof. The stern 67b extends through and is of ysmaller diameter than the exhaust port 264 to allow an air flow out through the port when the button 67e is pushed upwardly as shown in FIG. 4 to unseat the valve surfa-ce 67a from the O ring seat 261. Normally, the surface 67a will be seated against the O ring 261 because of the air pressure within the reset valve chamber 262, and unseating must be accomplished by manual upward movement of the valve.

In` order to operate the tool 10, a supply of the nails 34 carried on a relatively long length of the continuous flexible carrier strip 36 is loaded in the housing 38 in a ycoiled manner as shown in FIG. 2. The leading end of the .strip of nails is moved forwardly along the guide track 132 until the rst nail is engaged within the grooves 150 on the

sprockets

142 and 144 of the indexing means 40. Further forward movement of the nail strip causes the indexing means 40 to be rotated in a clockwise direction until the first nail in the strip is positioned `in the feed position immediately adjacent the feed open-ing 128 in the nosepiece assembly 30 as shown in FIG. 6. During this rotation of the indexing sprockets, successive nails become engaged within successive ones of the grooves 150 and the carrier strip of nails is moved forwardly along the guide track 132. The pawl 52 does not interfere with this rotation of the sprockets, since the forward end of the leg 169 will act as a ratchet and be deflected outwardly by each tooth of the sprockets. When the first nail in the strip reaches the feed position, the shank thereof will engage the side wall a of the short forward portion 135 of the guide track preventing further rotation of the indexing means 40, and the operator will then know that the lead nail in the strip is properly positioned in the feeding position.

When a compressed air source is connected to pressurize the reservoir handle 14 of the tool, the air flows freely into the upper cylinder 90 through the opening 18 and simultaneously ows through the interior of the tubular member 180 and out the bottom end thereof to ll the valve chamber 194. From the chamber 194, the air flows into the annular space 163 in the valve cylinder 54 via the bottom port 200, the passage 214, and the top port 166 in the valve cylinder 54. The air within the space 163 also flows into the reset valve chamber 262 via the bottom port 167 and causes the reset valve 67 to positively seat and close the exhaust port 264.

If the safety valve mechanism 58 is in the safe position shown in FIG. 1, air from the passage 214 flows into the passage 218 through the bores 62a and 62b of the valve element 62 or, if in the operated position, through the recess 62C. From the passage 218, air flows into the annular space 126 around the central stem 72 of the piston assembly 22 via the vertical passage 220, the horizontal passage 224, the vertical passage 226, and the port 124. This causes the sleeve Z4 to move upwardly and the piston assembly 22 to travel upwardly to the ring position shown in FIG. l in the manner previously described. In order to feed the rst nail in the strip from the feed position into the drive track the reset valve 67 is momentarily depressed which unseats the O ring 66 from the port 222 at the rear of the valve cylinder 54 allowing air pressure to enter the rear end of the cylinder and move the operator piston assembly 50 on a forward or feeding stroke.

The forward travel of the operator piston assembly 50 causes the pusher 42 to move forwardly so that the tips 42a and 42e engage the head and lower shank respectively, of the lead nail 34 which has been previously placed in the feeding position. Th-is forward movement of the lead nail severs the carrier strip 36 immediately adjacen-t the shank of the nail, allowing the nail to be separated from the strip and fed forwardly through the opening 128 into the drive track 28. As previously described, as soon as the head of the nail completely clears the upper portion 12861 of the feed opening 128, the nail will drop downwardly in the drive track until the head thereof is engaged by the nail retaining member 152 which holds the nail within the drive track as shown in FIG. 1.

The forward travel of the operator piston assembly 50 and the pusher 42 lis stopped when the forward shoulders 42e of the pusher engage the rear face 30a of the nosepiece assembly. Because of the lost motion connection between the pawl 52 and the operator piston assembly 5i), the former does not move during the rst portion of forward travel of the latter. During the later portions of the forward travel of the operator piston assembly, however, the leg 168 of the pawl engages the shoulder 155 and the pawl then moves forwardly. During this forward movement of the pawl, the groove engaging member 170 thereof is deflected laterally outward by engaging the teeth of the

indexing sprockets

142 and 144 as previously described until nally after clearing the teeth it can move into engagement with the next successive groove of the sprockets. Also, toward the end of the forward travel of the operator piston assembly 50, the shoulder 157 engages the lower end of the operator 238 to pivot this operator in a clockwise direction so that its upper end 244 holds the ball 236 .away from seating engagement with the O ring seat 234 surrounding the exhaust port 232. If the pusher 42 and operator piston assembly 50 is prevented from moving to the full forward position because of a nail jamming in the feed slot 128, or drive track 28 the .shoulder 157 will not engage the operator 238 to unseat the ball 236. As previously described, when this happens the tool cannot be fired and it is necessary to clear the jam before a firing stroke can be initiated.

When it is desired to drive the nail which has been positioned in the drive track, the tool is disposed with the lower end of the nosepiece assembly resting against the workpiece 60 into which the nail is to be driven. This causes the safety valve mechan-ism 58 to move to the rire position previously described. The trigger 46 is then depressed to the position shown in FIG. 3 by the operator to move the lower valve surface 188 against the lower O ring `seat 198 in the valve chamber 194 and to unseat the upper valve surface 190 from the upper O ring seat 196. When this occurs, the annular space 126 about the stem 72 of the piston assembly 22 is connected to the atmosphere via the port 124, the

passages

226, 224, 220, 218, the annular groove 62C in the valve element 62, the passage 216, the valve chamber 194, the annular space 195 within the slideway 184, the passage 230, the ball valve chamber 228, and the exhaust port 232. As previously described, when the annular space 126 is connected to the atmosphere, a ring stroke is initiated with the piston assembly 22 moving rapidly downward so that the driving element 26 drives the nail in the drive track 28.

When the space 126 is vented to the atmosphere, the right-hand or rear end of the cylinder 54 is also vented to the atmosphere because the end port 222 is in communication with the vertical passage 220. occurs, the operator piston assembly 50 moves rapidly toward the rear because the air pressure within the annular space 163 acting on the rear piston portion 160 is no longer balanced by the pressure in the rear end of the cylinder 54. During the initial portion of the rearward travel of the operator piston assembly 5t), the shoulder 157 moves out of engagement with the lower end of the ball valve operator 233 allowing this operator to pivot so that the ball 236 seats against the O ring seat 234 under the influence of the air pressure in the chamber 22S closing the exhaust port 232.

Thus, when the trigger 46 is released by the operator, the tubular member 180 moves upwardly, and air pressure again enters the space 126 and the rear end of the cylinder 54 through the valve chamber 194, the passa-ge 216, the annular groove 62C in the valve element 62, and the

passages

213, 220, 224, and 226. When the annular space 126 is again pressurized, the sleeve 24 moves upwardly; and the piston assembly 22 and driving element 26 move upwardly on a return stroke as previously described. Also when the rear end of the valve cylinder 54 is again pressurized, the operator piston assembly 50 starts its forward movement to feed another nail from the feeding position into the drive t-rack 28.

During the initial portion of the rearward travel of the operator piston assembly 50 the pusher 42 moves rearwardly so that the tips 42a and 42C thereof are clear of the forward end of the guide track 135 as previously described to allow the next nail in the strip to be indexed into the feed position and during this time the pawl 52 remains stationary because of the lost motion connection between the former and latter. During the later portion of the rearward travel of the operator piston assembly, the bight 42j of the pusher 42 engages the leg 168 of the pawl 52 causing the latter to move rearwardly. As the pawl 52 moves rearwardly, the member 170 causes the

sprockets

142 and 144 to rotate clockwise an amount equal to the width of a tooth and a groove. The rotation of the sprockets is stopped after this amount of rotation by the engagement of the next nail in the strip with the wall 135a of the short forward end 135 of the guide track 132 (FIG, 6). When this engagement occurs, the rearward travel of the operator piston assembly 50 and the pawl 52 is stopped in the position shown in FIG. 3 because of the connection between the pawl 52, the sprockets When this

u

142 and 144, and the operator piston assembly Si). Thus, the amount of rearward travel of the operator piston assembly 5t) is dependent on whether a nail reaches the wall g at the forward end of the guide track 132.

After the last nail in the strip has been driven, there are no means for limiting the amount of rotation of the sprockets and the amount of rearward travel of the operator piston assembly 50. Accordingly, after the last nail has been driven, the operator piston assembly will travel rearwardly past the position of FIG. 3 until the valve member 66 at the rear end thereof engages the end port 222 of the valve cylinder 54 to close it as shown in FIG. 4. When this occurs, compressed air cannot enter the rear end of the cylinder 54 to move the operator piston assembly 50 forwardly, and the shoulder 157 will not engage the ball valve operator 238 to `open the ball valve 236. With the ball valve 236 free to move in the chamber 228, it will always seat to close the exhaust port 232 whenever pressure is supplied to the chamber from the passage 230. Thus, if the trigger 46 is depressed to fire the tool no air can be exhausted from the annular space 126 -because the ball valve will immediately seat to close the exhaust port 232. Thus, after the last nail is driven, the tool is automatically disabled so that it cannot be fired. This is highly desirable since it has been found that ring tools of this type when there are no fasteners in them adversely affects the life of the tool.

In order to move the operator piston Iassembly 50 out of the position shown in FIG. 4 so that the tool 10 can be used after reloading the magazine assembly with a new supply of nails, the reset valve 67 is momentarily depressed by the operator. This unseats the surface 67a from the O ring seat 260 and allows the air in the annular space 163 to be exhausted to the atmosphere through the exhaust port 264. When the pressure in the space 163 is reduced suiciently, the air pressure in the end port 222 acting against the rear end of the operator piston assembly 50 moves the piston assembly forwardly to unseat the valve 66 and allow the rear end of the cylinder 54 to become pressurized. This action causes the operator piston assembly 50 to move forwardly and feed the lead nail into the drive track as previously described and the tool is again ready for use.

Momentary unseating of the reset valve 67 as just described, will not re the tool since the top port 166 is small enough to prevent a rapid flow of air from the annular space 126 into the annular space 163 and out the port 264, and thus, the pressure within the space 126 is not reduced enough to cause -ring of the tool. Moreover, high pressure air is continually supplied to the passage 214 and the annular space 163 yfrom the lower end of the tubular member and further tends to prevent the evacuation of the annular space 126 when the reset valve 67 is actuated. Only a small reduction of pressure in the space 163 is required to cause the valve 66 to -be unseated; and once unse'ated, the operator piston -assembly 50 is moved forwardly because of the air pressure entering the rear end of the valve cylinder 54 through the port 222.

Another method of firing the tool is possible by maintaining the trigger 46 in a continually depressed position as shown in FIG. 3 and positioning the nosepiece assembly 30 against the workpiece 66 whenever it is desired to drive a nail. When this is done, the safety valve 5S operates as a triggering mechanism in allowing the annular space 126 to be connected to the atmosphere via the

passages

226, 224, 220, and 218, the annular groove 62C, the passage 216, the chamber 194, the annular space 195, the passage 230, the valve chamber 228, and exhaust port 232 when the safety valve is in the fire .position as shown in FIG. 3. After tiring in this manner, the piston assembly 22 will not return to the top of the chamber 16 as shown in FIG. l until the nosepiece 30 is moved away from the workpiece 60 to allow the safety valve 58 to move to the safe position. Thus, it is possible to re the tool by maintaining the trigger in a continually depressed position .and successively positioning the nosepiece assembly 30 of the tool against the workpiece at the points where the nails are to be driven. After a driving or firing stroke of the tool has been completed, the piston assembly 22 will remain -at the lower end of the chamber 16 until either the trigger 46 is released or the nosepiece assembly 30 of the tool is moved away from the workpiece allowing the safety valve 58 to move to the safe position.

When either of these events occurs, the piston assembly 22 wil-l move to the upper end of the chamber 16 on a return stroke in preparation for another firing stroke. The tool can be fired either in the normal manner by positioning the nosepiece assembly 30 against a workpiece and then squeezing the trigger 46, or in the manner just described by rst squeezing the trigger and then placing the nosepiece 30 against the workpiece to fire the tool. The latter method of tiring the tool is occasionally desirable for the rapid driving of nails in a large workpiece where the tool is moved rapidly and nails are driven at appropriate intervals in the workpiece. The former method of firing the tool is more appropriate where accurate positioning of the nails is important.

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

What is claimed as new and desired to be secured by Letters P-atent of the United States is:

1. In a tool for driving fasteners supplied from a carrier strip, said tool including a drive track and a driver slidable therein; feed sprocket means having a plurality of fastener receiving grooves spaced around the periphery thereof, each groove receiving a successive fastener in the carrier strip upon rotation of said sprocket means to positively move said fasteners toward said track; and means for separating the fasteners moved into a position adjacent said drive track from the carrier strip and feeding said fastener into said drive track in timed sequence with the rotation of said sprocket means and movement of said driver.

2. In a tool for driving fasteners supplied from a carrier strip including fastener driver movable in a drive track; the combination including feed sprocket means having a plurality of fastener receiving grooves spaced around the periphery thereof, each groove receiving a successive fastener in the carrier strip upon rotation of said sprocket means to positively move said fasteners to a feed position adjacent said drive track; fastener pusher means reciprocally movable to engage a fastener in said feed position and separate said fastener from said carrier strip for movement into said drive track; and means for rotating said sprocket means to index successive fasteners into said feed position and thereafter moving said pusher means to separate said fastener in said feed position from said carrier strip and move said fastener into said drive track.

t3. A tool for driving fasteners supplied from a carrier strip comprising a drive .track havin-g a fastener feed opening in a wall thereof; a driver movable in said drive track to drive fasteners positioned therein; feed sprocket means having a plurality of fastener receivin-g grooves spaced around the periphery thereof, each groove receiving a successive fastener in the carrier strip, Asaid sprocket means rotatable about an axis for moving said fasteners into a feed position adjacent said feed opening in said drive rtrack: guide means having a forward portion disposed along -a portion of the periphery of said sprocket means for guiding said fasteners into the grooves of said sprocket means for movement into said feed position; fastener pusher means engageable with the fasteners' in said feed position forseparatin-g successive fasteners from said strip and moving these fasteners through said feed opening into said Idrive track, said pusher means reciprocally movable in a radial plane extending through said feed position and the axis of said sprocket means; and means for rotating said sprocket means to index successive fasteners in said feed position and thereafter moving said pusher means to separate the faste-ners from the strip and feed said separated fasteners into said drive track prior to a driving stroke of said driver.

4. A tool for 'driving fasteners supplied from a carrier strip comprising a structure forming a drive track and a fastener driver slidable in said drive track, feed sprocket means having a plurality of fastener receiving grooves spaced around the periphery thereof, each Igroove receiving a successive fastener in the carrier strip, said sprocket means rotatable about an axis parallel to said drive track for moving successive fasteners into a feed position adjacent said drive track, guide means having a forward portion coextensive with a portion of the periphery of said sprocket means for guiding successive fasteners into engagement with said grooves, fastener pusher means engageable with each successive fastener positioned in said feed position for separating said fastener from the strip and moving it into said drive track, means for rotating said sprocket means to index each successive fastener into said fee-d position, and means for moving said pusher means to separate a fastener from the strip and :feed said fastener into said drive track in timed sequence with the movements of said driver.

5. A tool for drivin-g fasteners supplied from a carrier strip comprising a drive track and a driver slidable in said drive track to drive fasteners positioned therein; feed l sprocket means adjacent said drive track having a plurality of fastener receiving grooves spaced around the periphery thereof, each groove receiving a successive fastener in the carrier strip upon rotation of said sprocket means for moving said fasteners toward said drive track; guide means for guidalbly supporting said strip of fasteners and positioned to lie adjacent a portion of the periphery of said sprocket means to guide said fasteners into said groove-s thereof; fastener pusher means engageable 'with each successive fastener positioned adjacent said drive track for separating said fastener from said carrier lstrip and moving said fasteners into said drive track, said pusher means reciprocally movable toward and away from said drive track, and means for rotating said sprocket means to index successive fasteners into a position adjacent said drive track and thereafter moving said pusher Imeans to separate each said fastener from said carrier strip and feed said Ifastener into said =drive track in timed sequence with the movements of said driver.

`6. A magazine assemlbly for feeding successive fasteners supplied from a carrier strip into the drive track of a ydriving tool having a driver slidable lin said track comprising guide means for guiding the strip of fasteners to position each successive lead fastener of the strip in a feed position adjacent said drive track, fastener indexing means :including fastener receiving grooves around the periphery thereof for receiving successive fasteners in the stnip, said indexing means rotatable to move the strip of fasteners along said guide means to index successive lead fasteners thereof in said feed position and pusher means rec-iprocally movable for separating each successive fastener moved into said feed position from said strip and moving said fastener into said drive track.

y7. A magazine assembly -for feeding fasteners supplied from Ia carrier strip into the drive track of a driving tool, said tool including a driving element slidable in said track, comprising guide means for guiding the fasteners of said strip into a position adjacent said drive track, fastener indexing means [having a plurality of fastener receiving grooves around the periphery thereof, said indexing means rotatable to receive successive faste-ners in the strip for moving said fasteners Ainto said position and nail pusher means movable to separate the rfasteners in said position from said carrier strip and feed t-hem one at -a time into said drive track.

8. A magazine assembly for feeding `fasteners supplied from a carrier strip into the drive track iof a driving tool having a reciprocally movable driver in said drive track comprising a base structure having la cylinder therein and operator piston means slidably disposed in said cylinder, guide means in said structure for guiding the fasteners in said strip into a position -adjacent said drive track, indexing means having teeth and fastener receiving grooves lspaced alternately around the periphery thereof, said indexing means rotatable about a central axis to receive .successive fasteners of the strip 'within the grooves and Iindex successive fasteners in said position, Ipusher means secured to said operator piston means for separating the fasteners in said position from said strip and moving the separated fasteners into said drive track upon a forward stroke of said piston means `and pawl means operatively interconnecting said piston means `and said indexing means for engaging sa-id 'teeth to rotate said latter means an amount necessary to move the next successive fastener into said position upon a rearward stroke of said piston means.

9. A pneumatically operated magazine assembly for feeding fasteners supplied from a carrier strip into the drive track of a pneumatic driving tool having a reciprocal driver disposed in said drive track comprising a base structure having a cylinder therein, operator piston means slidably disposed in said cylinder, guide means in said structure for guiding the fasteners of said strip into a position adjacent said drive track, indexing means rotatably mounted on said structure including sprocket means having fastener receiving grooves spaced around the periphery thereof, said sprocket means rotatable in one direction to receive successive fasteners of the strip within said grooves and move the fasteners along said guide means toward said position, pawl means interconnecting said indexing means and said operator piston means to rotate said indexing means in said one direction in an amount to index the each successive fastener of the strip into said position on repetitive `rearward vstrokes of said operator piston means and pusher means attached to said operator piston means and movable therewith on repetitive forward strokes to engage successive fasteners lpositioned in said position and separating said fasteners from said strip and moving said separated fasteners into lsaid drive track.

10. A pneumatically loperated magazine assembly for feeding successive fasteners supplied from a carrier strip into the drive track of a pneumatic driving tool having a reciprocal driver disposed in said drive track, said assembly comprising a base structure defining a cylinder having a closed rear end and an open forward end, operator piston means slidably disposed in said cylinder, guide means in said structure for guiding the fasteners in said strip into a position adjacent said drive track, rotatable indexing means for moving said fasteners along said guide means to index successive fasteners in said position, pawl means interconnecting said indexing means and said voperator piston means for rotating the former a predetermined amount on a rearward stroke of the latter to move a next successive fastener in the strip into said position, pusher means secured to the forward end of said operator piston means for engaging each successive fastener in said position to separate said fastener from the carrier strip and move -it into the drive track on a forward stroke of said operator piston means, and means `responsive to the absence of a fastener in said position permitting said indexing means to rotate more than said predetermined amount whereby said operator piston means moves to a fully retracted position.

11. A pneumatically operated magazine assembly for lfeeding successive fasteners supplied from a carrier strip into the drive track of a pneumatic driving tool includling a reciprocal driver disposed in said drive track and movable on a drive stroke in response to actuation of valve means and movable on a return stroke upon release of said valve means, said 4assembly comprising a base structure defining a cylinder having an open forward end and a closed rear end, operator piston means slidably disposed in said cylinder movable on a forward stroke in response to pneumatic pressure in the rear end of said cylinder and movable on a rearward stroke upon reduction of pneumatic pressure in the rear end of said cylinder, guide means for guiding the fasteners of said strip to position successive fasteners in a feed position adjacent said drive track, fastener indexing means rotatably' mounted on said structure including fastener receiving grooves around the periphery thereof for receiving successive fasteners of the strip to move them into said feed position upon rotation of said indexing means, pawl means interconnecting said indexing means and said piston means for rotating the former means a predetermined amount upon a rearward stroke lof the latter means to index successive fasteners of the strip into said feed position, pusher means secured to the forward end of said operator piston means for separating successive fasteners in the feed position from said carrier strip and moving said separated fasteners into said drive track upon a forward stroke of said piston means, and means responsive to the absence of a fastener in said feed position permitting said indexing means to rotate more than said predetermined amount whereby said operator piston means moves into a full retracted position and is maintained therein -regardless of the actuation of said valve means.

12. A pneumatically operated fastener driving tool for driving successive fasteners supplied from a carrier strip, said tool comprising a drive track and a driver slidable therein, a piston assembly in said tool carrying said driver and movable on a downward driving stroke and an upward return stroke, trigger valve means for actuating said pist-on assembly to move on a drive stroke when depressed and a return stroke when released, safety valve means responsive to the position of a lower end of said drive track in relation to a Work piece for preventing a drive ,stroke of said piston assembly when said lower end is away from said work piece, a magazine assembly for feeding successive fasteners from said carrier strip into .said drive track, said assembly including a base structure defining cylinder means having an open forward end and :a closed rear end, operator piston means slidably disposed in said cylinder means and movable on a forward feed stroke and a rearward indexing stroke in response to pneumatic pressure in the rear end of said cylinder means, rotatable fastener indexing means for indexing successive fasteners of the carrier strip into a feed position adjacent said drive track, pawl means interconnecting said indexing means to said operator piston means for rotating said former means an amount required to index the next successive fastener in the strip into said feed position upon a rearward stroke of said latter means, pusher means secured adjacent the forward end of said operator piston means and movable on a forward stroke of the lattter means to positively separate the fastener in said feed position from said strip and move said fastener into said drive track, rst passage means interconnecting said trigger valve means and said cylinder means for exhausting the rear end thereof on depression of said trigger vvalve means permitting said operator piston means to move rearwardly, lsecond passage means interconnecting said trigger valve means and said cylinder means for supplying pneumatic pressure to said cylinder means intersupplied to the rear end of said cylinder for moving said operator piston means forwardly.

13. In a tool for driving fasteners supplied from a carrier strip, said tool including a fastener driving element; the combination comprising a drive track for said driving element having a fastener feed opening in a wall thereof; feed sprocket means having a plurality of fastener receiving grooves spaced around the periphery thereof, each groove adapted to receive successive fasteners in the carrier strip, said sprocket means rotatable t-o positively move the fasteners in said grooves into a feed position adjacent said feed opening; and means for severing the carrier strip adjacent said feed position and feeding the fasteners from said feed position radially outward from said groove through said feed opening into said drive track in timed sequence with the rotation of said sprocket means and movement of said driving element.

14. A pneumatic tool for driving fasteners supplied from a carrier strip comprising a drive tnack and a fastener driving element slidably disposed therein for downward movement on a driving stroke and upward movement on a return stroke, pneumatically actuated piston means for moving said driving element on said return stroke when pneumatic pressure is supplied to one side thereof and on said driving stroke when said one side is vented to the atmosphere, trigger valve means operable to control said piston means for movement on a driving stroke when depressed and on a return stroke when released, safety valve means operatively associated with said trigger valve means and said piston means for preventing a driving stroke of said piston means in response to a safe position of said tool relative to a work piece, said safety valve means including means normally extending below the lower end of said drive track when in a safe position and engageable with a work piece and movable upwardly to a fire position when the lower end of said drive track er1- gages said work .piece and a pneumatically actuated fastener feeding assembly for supplying fasteners from said carrier strip one at a time to said drive track in selected synchronisrn with the movement of said driver.

15. A pneumatic tool for driving fasteners supplied from a carrier strip comprising a drive track with a driving element slidably disposed therein for downward movement on a driving stroke and upward movement on a return stroke, pneumatically actuated piston means connected to said driving element for moving said element on a driving stroke and return stroke in response to the absence of pressure and to the presence of pressure, respectively, supplied to one side thereof, trigger valve means operable to control said piston means on a driving stroke when depressed and a return stroke when released, respectively, safety valve means operatively associated with said trigger valve means and said piston means and responsive to the position of the lower end of said drive track for preventing the depressurization of said one side of said piston means when in a safe position regardless of the position of said trigger valve means, said safety valve means including rod means normally extending below the lower end of said drive track when in a safe position and movable upwardly by engagement with a work piece to a re position permitting said trigger valve means to depre-ssurize said one side of said piston means to initiate a drive stroke, a pneumatic magazine assembly for feeding successive fasteners on said carrier strip one at a time into said drive track, said magazine assembly including fastener indexing means having a rotating member with grooves spaced apart around the periphery thereof for receiving successive fasteners in the ycarrier strip and indexing said fasteners to a feed position adjacent lsaid drive track, reciprocal pusher means movable on a forward stroke to engage fasteners in said feeding position and separate them from said strip and feed them into said drive track, operator piston means operatively associated with said trigger valve and safety valve means for moving sai-d pusher forwardly upon a return stroke of said driving element and rearwardly on a driving stroke of said elementuand pawl-means interconnecting said operator piston means and said indexing means for rotating the latter to index the next fastener in said feed position upon rearward movement of said operator piston means.

16. A pneumatic magazine assembly for feeding successive fasteners supplied from a carrier strip, one at a time, into a drive track of a tool for driving by a downward stroke of a driving element disposed in said track comprising a housing for containing a supply of fasteners carried by said carrier strip, guide means for supporting and guiding the movement of the fasteners in said strip from said housing to a feed position adjacent said drive track, rotary indexing means having a plural-ity of spaced apart grooves around the periphery thereof for receiving successive fasteners in the strip and moving the fasteners along said guide means to position successive fasteners in said feed position, reciprooally movable pusher means movable forwardly to engage fasteners in said feed position to separate them from said strip and feed them one at a time into said drive track prior to a -driving stroke of said fastener driving element and movable rearwardly to a retracted position, pawl means having a resilient forward end receivable within the grooves of said indexing means and movable rearwardly with said pusher means to rotate said indexing means until the next successive fastener in the strip reaches said feed position, said guide means including a surface engageable with the fastener in said vfeed position to limit the rotation of said indexing means and the rearward movement of said pawl means and said pusher to said retracted position, operator piston means slidably disposed in cylinder means of said magazine assembly, said piston means having a forward end secured tol said pusher and including a lost motion mechanism interconnected to said pawl means for allowing relative sliding movement therebetween, said piston means further including a first cylindrical piston portion and a second larger diameter piston portion spaced rearwardly therefrom defining an -annular cav-ity between said portions wi-thin said cylinder means, and means for controlling air pressure supplied to said annular cavity and for controlling air pressure supplied to the rear of said second piston portion in said cylinder means.

17. Apparatus as defined in claim 16 including trigger valve means depressible for initiating a driving stroke of said driving element and releasable to initiate a return stroke thereof, and means operatively associ-ated with said trigger valve means for simultaneously reducing the air pressure in said cylinder means rearwardly of said second piston porti-on causing rearward movement of said operator piston means when said trigger valve means is depressed and for simultaneously pressurizing said cylinder means rearwardly of said second piston portion to cause lforward movement of said operator piston means when said trigger valve means is released.

18. Apparatus as defined in claim 17 including safety valve means for preventing a driving stroke of said driving element when in a safe position, said safety valve means including structure normally extending below the lower end of said drive track when in said safe position and movable to a tire position when the lower end of said drive track is in close proximity to a work piece.

19. Apparatus as defined in claim 2 wherein said pusher means includes upper and lower forward tips engageable with the head and lower shank, respectively, of the fasteners in said feed position, said pusher means being movable between a full forward position wherein forward surfaces of said tips are adjacent said drive track and a rearward position wherein said tips are spaced rearwardly from said drive track.

20. Apparatus as defined in claim 19 wherein said means for rotating said sprocket means and moving said pusher means includes structure opera-ble to rotate said sprocket means to move 4a next successive fastener into said feed position after a predetermined amount of rearward movement of said pusher means from said full forward position. v

21. Apparatus as defined in claim 19 including means for simultaneously initiating a downward driving stroke of said driver and a rearward stroke of said pusher means from said full forward position.

22. Apparatus as defined in claim 19 including actuating means for initiating a downward driving stroke of said driver and disabling means operatively associated with said pusher means for preventing a driving stroke of said driver unless said pusher means is positioned in said full forward position.

23. A fastener driving tool comprising structure defining a drive track for receiving fasteners, power 4actuated fastener driving means including a fastener driving element slidable in the drive track, a repetitively movable fastener feeding means operable through a cycle to feed `a fastener to the drive track incident to each operation of the fastener driving means, and means controlled by the fastener feeding means and operable to prevent operation of the fastener driving means when the fastener feeding -means -fails to completely feed a fastener into the drive track.

24. A fastener driving tool comprising a drive track for receiving fasteners, power actuated fastener driving means inc-luding a driver slidable in the drive track to drive successive fasteners positioned therein, a repetitively lmovable fastener feeding means operable through a feeding cycle to feed successive fasteners from a carrier strip into said drive track prior to each repetitive driving stroke of said driver, said feeding means including -a pneumatically operated pusher means movable forwardly on a feeding stroke to a full forward position whereby a fastener is moved into said drive track and rearwardly yon a return stroke to a rearward position, and means -actuated by said feeding means for preventing a driving stroke of said driver until said pusher means reaches its full forward position.

25. A fastener driving tool comprising a drive track for receiving fasteners, pneumatically actuated fastener driving means including a driver slidable in said drive track and repetitively movable on driving strokes to drive successive fasteners positioned in the drive track, said driving means including valve means for controlling the operation of the driver, a repetitively movable fastener feeding means operable through a feeding cycle for feeding successive fasteners into said drive track for driving by said driver, and means controlled by said fastener feeding means to control said valve means.

2'6. A fastener feeding mechanism operable through feeding cycles to feed successive fasteners into a drive track of a tool having a slidable driver in the track movable through repetitive drive strokes to drive fasteners supplied to the drive track, said mechanism comprising repetitively movable fastener feeding means engageable with successive fasteners during feeding strokes thereof for moving said fasteners into said drive track, and means operable for preventing a drive stroke of said tool until said feeding means has completed a feeding stroke moving a fastener into said drive track.

27. A fastener feeding mechanism operable through a repetitive feeding cycle to feed successive fasteners into a drive track of a driving tool having a power actuated driving element slidable in said drive track, said mechanism including piston lmeans movable forwardly on a feed stroke for feeding a fastener into said drive track prior to a driving stroke of said driving element, and means associated with said piston means and said power actuated driving element for preventing a driving stroke of said driving element until said piston means reaches a forward feed position wherein a fastener has been moved into said track.

28. A pneumatic fastener driving tool including a drive track for receiving fasteners and a repetitively moving driver slidably mounted in said track and movable downwardly on a driving stroke, pneumatically actuated power means for moving said driver to drive a fastener supplied to said drive track, said power means including valve means operable to an open position to permit a driving stroke of said driver and normally closed to prevent a driving stroke, a repetitively operable -fastener feeding means movable forwardly on a feeding stroke to feed successive fasteners into said track incident to each operation of said driver, said feeding means including pneumatic piston means Ioperable to move said fasteners into said track when moved to a forward position, and means operatively interconnecting said piston means and said valve means to 4open said valve means only when said piston means reaches said forward position.

29. A fastener driving tool including a power actuated driver slidably mounted within a drive track for driving fasteners positioned therein, fastener feeding means including magazine means and operable through a feeding cycle for moving successive fasteners into said drive track, control means for initiating a driving stroke of said driver, means operatively associated with said control means and responsive to the absence of fasteners in said magazine for preventing a driving stroke of said driver, and means controlled by said feeding means for preventing a driving stroke of said driver when said feeding means has not fed a fastener from the magazine into the drive track.

30. A fastener driving tool including a power actuated driver mounted for repetitive sliding movements in a drive track to drive fasteners positioned therein, fastener feeding means operable through repetitive cycles for feeding successive fasteners into said track, and means responsive to the position of Said feeding means for preventing a drive stroke of said power actuated driver until a fastener is positioned in said drive track.

31. A fastener driving tool comprising a drive track for receiving fasteners and a reciprocally movable driver mounted therein and movable through a drive stroke and a return stroke, fastener feeding means for moving successive fasteners into said drive track Ifor driving by said driver, said feeding means including piston means movable through a feeding stroke to feed a fastener into said track and a rearward stroke, pneumatic means for moving said driver on said driving and return strokes including valve means for initiating a drive stroke and safety valve means for preventing a drive stroke when in a safe position, and means responsive to the position of said piston means for preventing a drive stroke when said piston means is not disposed in a predetermined position.

.32. In a fastener driving tool of the type including a drive track and a fluid actuated driver movable in said track on a power stroke in response to lluid pressure, the combination including a rotatable sprocket means having grooves therein for receiving fasteners and feeding successive fasteners toward said drive track, control valve means for controlling the tlow of fluid for moving said driver on a power stroke, and valve means responsive to the absence of a fastener in a groove of said sprocket means for rendering said control valve means ineffective.

33. In a fastener driving tool of the type including a drive track and a iluid actuated driver movable in said track on a power stroke in response to iluid pressure, the combination including sprocket means having alternate grooves and teeth around the periphery thereof and rotatable about an axis to move successive fasteners received in said grooves toward said drive track, trigger valve means for controlling the ilow of pressurized fluid to actuate said driver on a power stroke, and valve means including piston means slidable in response to the absence of a fastener in a groove of said sprocket means for rendering said trigger valve means ineffective.

34. In a fastener driving tool of the type including a drive track, a fluid actuated driver movable in said track in response to fluid pressure and trigger valve means for controlling the ilow of iluid to move said driver on a power stroke, the combination including a magazine assembly for holding a supply lof fasteners and feeding them into said drive track, said assembly including fastener indeXing means having spaced-apart grooves around the periphery thereof and teeth abetween adjacent grooves for engaging fasteners in the grooves and moving them toward said drive track upon rotation of said indexing means about an axis, means for rotating said indexing means to move successive fasteners toward said drive track and valve means responsive to the absence of a 24 fastener withinv a groove adjacent said drive track for rendering said trigger valve means ineective to initiate a power stroke of said driver.

No references cited.

GRANVILLE Y. CUSTER, JR., Primary Examiner.

Claims

1. IN A TOOL FOR DRIVING FASTENERS SUPPLIED FROM A CARRIER STRIP, SAID TOOL INCLUDING A DRIVE TRACK AND A DRIVER SLIDABLE THEREIN; FEED SPROCKET MEANS HAVING A PLURALITY OF FASTENER RECEIVER GROOVES SPACED AROUND THE PERIPHERY THEREOF, EACH GROOVE RECEIVING A SUCCESSIVE FASTENER IN THE CARRIER STRIP UPON ROTATION OF SAID SPROCKET MEANS TO POSITIVELY MOVE SAID FASTENERS TOWARD SAID TRACK; AND MEANS FOR SEPARATING THE FASTENERS MOVED INTO A POSITION ADJACENT SAID DRIVE TRACK FROM THE CARRIER STRIP AND FEEDING SAID FASTENER INTO SAID DRIVE TRACK IN TIMED SEQUENCE WITH THE ROTATION OF SAID SPROCKET MEANS AND MOVEMENT OF SAID DRIVER.