US2653316A - Hammer stapler - Google Patents

Description

Sept. 29, 1953 w. R. BECKMAN ETAL HAMMER STAPLER 6 Sheets-Sheet 1 Filed Oct. 28, 1950 www QM Tz-JFE Iii UTE William 7?. Beck/wan Char/es E. Crooks Sept. 29, 1953 w. R. BECKMAN ETAL HAMMER STAPLER 6 Sheets-Sheet 2 Filed Oct. 28, 1950 Sept. 29, 1953 w. R. BECKMAN ETAL HAMMER STAPLER Filed Oct. 28, 1950 BFEIZZLUVT William 7?. Bea/(man Charles 1', Crooks w flrhu: W I! p 1953 w. R. BECKMAN ETAL 2,653,316

HAMMER STAPLER 6 Sheets-Sheet 4 Filed Oct. 28, 1950 .100 F4 5- 6 10 11. 1 M 8 I 7 .05 25 .184 I" I I I iii J79 m w W 9 4m llllllllll ll M w WW mm a? w I IhI ETIZUT William 7?. Bea/(man Char/es E. Crooks Sept. 29, 1953 w. R. BECKMAN ETAL 2,

HAMMER STAPLER Filed 001:. 28, 1950 6 Sheets-Sheet 5 1571 5 I722: 12- William 7?. Bee/ man Char ea 2". Crooks Sept. 29, 1953 Filed Oct. 28, 1950 W. R. BECKMAN ETAL HAMMER STAPLER 6 Sheets-Sheet 6 5,13% 1 III b wam ze Charles E Crooks 'uf r William 7?. Beckman Patented Sept. 29, 1953 HAMMER STAPLER William R. Beckman,

E. Crooks, Evanston, Ill., assignors to Spotnails, Inc., Evanston, 111., a corporation of 1111- nois Chicago,

and Charles Application October 28, 1950, Serial No. 192,762

37 Claims. 1

The present invention relates to improvements in stapling devices and more particularly concerns a hammer stapler.

Among the more important objects of the invention is the provision of a hammer stapler capable of carrying a substantiial roll of partially formed sheet metal staples from which individual staples are successively formed and driven in the use of the stapler.

Another object of the invention is to provide in a hammer stapler improved means for forming and driving the staples.

A further object of the invention is to provide in a stapling machine an improved construction including a plurality of unitary subassemblies whereby a staple driving and a staple feeding unit are arranged in the form of cartridge subassemblies that can be easily and quickly assembled in a supporting casing or removed when desired, thus greatly facilitating servicing or repair of the machine whenever required.

Still another object of the invention is to provide an improved hammer stapler embodying various novel features in structural relationships which will provide extreme sturdiness, durability and efiiciency together with light weight.

Yet another object of the invention is toprovide a hammer stapler capable of carrying an unusually large load of staple blanks in a magazine so disposed that not only does it assist in the handling of the device for drivingstaples but also places the staple load well forwardly in the machine so that the center of mass is as near as practicable to the driving head of themachine.

A still further object of the invention is to provide an improved staple forming and driving assembly for a hammer stapler.

' hammer stapler.

' Also an object of the invention is the provision of animproved body and handle structure for a hammer stapler.

Other objects, features and advantages of the present invention will be readily apparent from 2 the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings, in which:

Figure l is a fragmental top plan view of a hammer stapler according to the invention;

Figure 2 is a fragmental side elevational view of the hammer stapler;

Figure 3 is an enlarged fragmental longitudinal sectional elevational view taken substantially on the line III--III of Fig. 1;

Figure 4 is an enlarged front or head end elevational View of the hammer stapler;

Figure 5 is an enlarged vertical sectional view through the magazine of the hammer stapler 7 taken substantially on the line VV of Fig. 2;

Figure 6 is an enlarged top plan view of the head end portion of the hammer stapler and partially in section taken substantially on the line VI-VI of Fig. 2;

Figure '7 is an enlarged fragmentary horizontal sectional view taken substantially on the line VII-VII of Fig. 3; p

Figure 8 is a fragmentary vertical sectional view taken substantially on the line VIIIVIII of Fig. 7;

Figure 9 isan isometric, more or less schematic view of a roll of sheet metal staple blanks of the kind which ar adapted to be used in the hammer stapler of the present invention;

Figure 10 is a fragmentary elevational view of the inside face of the lower portion of the front gate member of the stapler, looking generally in the direction of the arrows on th line XX of Fig. 7;

Figure 11 is a; top plan view of the staple blank strip feed unit;

Figure 12 is a side elevational view of the feed unit;

Figure 13 is a rear elevational view of the feed unit;

Figure 14 is a side elevational view of the replaceable staple driving and forming unit;

Figure 15 is a front elevational view of the driver and forming unit;

Figure 16 is a sectional detail view taken substantially on the line XVI-XVI of Figur 14;

Figure 17 is a sectional detail view taken substantially on the line XVII-XVII of Figure 14; and

Figure 18 is an enlarged fragmentary sectional detail view taken substantially on the line XVIII-XVIII of Fig. 2. I

' It is believed that the present invention provides the first hammer stapler to depart from the capacity limitations of prior staplers in which reliance was placed upon individual sticks or lengths of staples fed into the machine and limited as to length by the length of the staple magazine. This has necessitated frequent reloadings. By the present invention a hammer stapler is provided which is adapted to be loaded with staple blanks in a practical instance up to 1500 to 2000 units. Such staple units are adapted to be in the form of partially formed fiat staple blanks 28 (Fig. 9) formed successively in a sheet metal strip supplied in a roll R of the desired quantity or size and which may be conveniently supplied and handled for insertion in the hammer stapler wherein the individual staple units 2:; will be successively formed, severed from the leading end of the strip and driven from the machine into an object or surface into which the staple prongs are to penetrate.

General description of the hammer stapler According to the invention, the sam'fner stapler comprises a body 2| which is preferably formed from sheet metal stampings of any desired number of complementary parts brazed or welded together to provide a strong, light weight and durable body member and a casing 'or housing within which the staple rollR and the various feeding and driving mechanisms are housed. In a practical form, the housing or body member 21 has been made of two majorpartsa left hand and a right hand part stamped to forn and then Welded together edgewise along upper and lower marginal flanges into a single integral unit.

The rear end portion of the bcdymember gl is substantially elongated and appropriately shaped to provide a handle 22 of suitable length to be grasped in the hand of a user. The rear extremity of the handle is appropriately finished off by means of a knob-like tip or plug member 23 which closes the end of the handle shell and has a downwardly projecting retainer nose 24 which will prevent rearward slipping of th users hand from the handle in service. The handle tip member 23 may be formed from a suitable light weight metal such as aluminum or it may be formed as a molded plastic element.

Intermediate the handle 22 and the forward extremity portion of the body 2i of the hammer stapler and which forward extremity portion provides a staple feeding, forming and driving head 25 containing most of theactive mechanism of the device, is provided an enlargedsta-ple blank roll magazine 21. For practical reasons the magazine portion 21 of the hqusi-ng is disposed as close as practicable to the head portion 25 of the stapler and is as large vertically as practicable in order to house a staple blank strip roll R of as large a diameter as feasible so that a maximum number of staple blank units 23 can be loaded into the machine at any one time. In this manner, not only is the capacityof the machine at a maximum, but the mass distribution of the machine, implemented by the weight'of the roll of staple blanks, is most eificie'nt from a practical standpoint for a hammer'typ'e's'tapler, namely with the center of mass 'close to the driving tip of the hammer.

cludes a top wall portion 28 and a bottom wall portion 29 extending substantially right angu-.

larly to a side wall portion 30 at the right side of the assembly, considered when looking from the handle end toward the head end of the machine, and a side wall 3| completing the body shell structure of the magazine portion or section of the device. The spacing between the opposing top and bottom walls 23 and 29 and the right side Wall 30 and the opposing left side wall 3|, and the shape or configuration of the walls is dictated by dimensional requirements to receive a roll R of staple blanks and also to provide adequate reinforcement and stress resistance in the intermediate portion of the body casing 2| occupied by the magazine. It will be observed that the handle portion 22 of the body shell merges smoothly to juncture with the magazine encasing body section 21.

Inasmuch as the strip of staple blanks 20 in the roll R presents numerous burred and otherwise rough edges or surfaces not only at the sides but also at the periphery of the roll, means are provided within the magazine section 21 for not only efficiently supporting the -'roll R in the hammer stapler but also to eliminate or at least minimize abrasion or frictional resistance to free un'rolling 'of the roll as the staple blanks are used from the end of the staple blank strip. To this e'n'd, a cup-shaped liner 3-2 is porvlded within the magazine section 21 having a generally circular Wall 33 of an inside width or depthscmewhat greater than the width of the staple blahk strip in the roll Rand an inside diameter suincient to receive freely the roll R in the maximum diameter it may be supplied. Integral with the wall 33 is a back wall 34. Junctur'e of the liner walls 33 and 34 is on a fairly sharply defined or small radius corner 35 with the back wall 34 bearing in fac'e-to-f'a'ce relation against and secured as by welding, brazing or by a central rivet 35 to the opposing surface of the housing wall 3i). Additional stability in assembly is attained by having the corner 35 fit in a complementary annular reentrant corner or seat 3? provided therefor in the inner surface of the housing magazine wall portion 33.

By preference, the top and bottom walls 28 and 29 of the body shell are spaced substantially further apart than the diameter of the magazine liner wall 33 so as to lie in spaced relation thereto for, among other reasons, accommodating an inturned marginal housing flange 38 defining a circular opening a of a diameter to receive and support the outer margin of the liner wall 33 closely. There is thus provided by the magazine liner 32 a cavity defining a 'chamberopenir'ig toward the left'side of the hammer stapler within which the supply roll R is accommodated.

In order to minimize frictional resistance or abrasion contact of the periphery of the roll R with the inner surface of the liner wall 33, means are provided for limiting peripheral 'contactto a minimum. In an efficient'and simple form, such means comprise an intermediate inwardly projecting substantially annular rib 53 formed on the liner wall 33 in substantially centered relation for engagement by the central body and connecting area of the-staple blank strip which is free from the burrs resulting from stamping out of the stable blank 23 in the strip and which is of ample width to assure engagement with the peak or the spacer and friction eliminating rib 49. By having the rib 43 relatively narrow and of arcuate cross section, substantially line contact is maintained between the solid central portion of the staple blank strip as long as any of the'strip remains in the magazine and with substantial tolerance for limited transverse or rocking shifting of the strip due to the inevitable variables encountered in such a strip.

Frictional resistance or burr abrasion from the points of the staple blanks which make up the sides of roll R. is avoided by equipping the magazine with rotary anti-friction side plate structure comprising an inner or right side plate 4! and an outer or left side plate AZ. By preference the inner plate 4i comprises part of a rotary reel or spool E3 on which the roll R is mounted in the magazine. For this purpose the plate 4| is centrally apertured at 1-4 to fit rotatably about a central tubular hub 45. At its inner end, the hub 45 is provided with a laterally extending flange 4! bearing against the opposing inner surface of the wall 34 of the liner cup which is formed with a central embossment as projecting into the base portion of the hub 45 for centering purposes. The flange A! is fixedly secured to the liner wall 34 as by welding or brazing. Secured to the margin of the plate ii defining the central aperture 44 is a hub flange 49 of generally L-shaped cross section effecting bearing engagement with the surrounded base portion of the hub 45 and retained against outward displacement on the hub 45 by a retaining ring as seated in an annular groove 5! in the hub. As a result, the inner anti-friction plate ll is adapted to turn freely about the stationary hub t5 and is maintained in spaced relation to the liner wall 34 by the base flange d1 of the hub. It will be observed in Fig. 5 that the housing side wall 30 and the juxtaposed liner wall 3% are bulged or bowed outwardly to accommodate the thickness of the spacer and attachment flange 41 of the hub member. It will also be observed that the plate 4! is preferably formed to flare gradually slightly outwardly toward its perimeter so that while relatively close confinement of the inner portion of the staple blank roll R, indicated in dash outline in Fig. 5, against axial movement in the magazine is effected, increased freedom from binding is afforded toward peripheral margin of the retaining and anti-friction rotary plate 4|.

In order to avoid wear and friction at the intermediate portion of the hub member 45 which projects into and through a core hole 52 in the roll B (Fig. 9) engaged thereon, an anti-friction sleeve 53 is provided about the hub and which sleeve is preferably made from a self-lubricating synthetic plastic material such as nylon. The sleeve .53 may be freely rotatable upon the hub 45 or it may be in press fit relationship thereabout, or even molded directly on the hub.

The circular anti-friction disk or plate 42 is mounted in appropriately spaced relation to the disk or plate ti and adjacent to the outer edge of the liner wall 33. Since it is necessary to gain access to the magazine chamber to place a supply roll therein, the anti-friction disk 42 is mounted on the inner side of a closure member or door 54 constructed and arranged to close the magazine and to be opened for access therei-nto. Forthis purpose the door 5 preferably comprises a sheet metal stamping marginally shaped to bear in closing relation against the body wall 3| about the opening to the magazine chamber and has a rearwardly extending hinge portion 5'! appropriate hingedly'mounted between spaced complementary hinge bosses 58 on the body shell 2| rearwardly from the magazine chamber opening. The central portion of the door panel 54 is bulged outwardly and has an aperture 59 through which extends a reduced diameter portion 60 of an inwardly projecting stud post 6| secured to the door by upsetting or riveting an attachment head 62 over the outer margin of the door defining the opening 59. The stud member 6! serves as a hub or pintle bearing for an outturned central annular bearing flange 63 on the anti-friction disk 42. Retention of the disk 12 against axial displacement inwardly from the bearing stud 6! is effected bya retaining disk ring 64 locked in a groove 65 on an inner portion of the bearing stud. The construction and arrangement is such that the anti-friction disk 42 retoins the staple blank roll R. in place within the magazine when the door 54 is closed, and the disk 42 is freely rotatable with the roll as the roll unwinds as an incident to use of the staple blanks. As seen in Fig. 5, the anti-friction disk 42 is also preferably angled uniformly outwardly from the center towards its periphery so as to afford greater clearance for the sides of the staple blank roll progressively to the periphery of the anti-friction disk so as to easewithdrawal of the staple blank strip from the periphery of the supply roll, similarly as explained in connection with the cooperating antifriction disk 4!.

For retaining the door 545 closed in service, a latch is provided which in the present instance comprises a snap latch 61. This comprises a pair of shouldered latch fingers 6B pivoted on a pin, stud or pintle 69 carried by an inward extension l'fl on the disk bearing stud 6i to project into the outer end portion of the tubular hub member 55. The shouldered latch fingers 68 are biased by means such as oppositely tensioned arms ii of a torsion spring into a separated condition for latching engagement with the inner end of a keeper ferrule i2 secured within the outer end portion of the tubular hub 45. The keeper member 12 provides a flaring throat defined at its outer end by a lateral flange l3 spaced autwardly from the end of the tubular hub '35 and providing with the hub end an annular groove within which is secured a retainer snap ring it serving as a retainer for the sleeve bushing 53 and also as a protection against damage of the outer end of the sleeve bushing by the side edge of a staple roll when the same is inserted on the magazine reel spindle or hub. It will thus be apparent that the door 54 is held closed by the latch El but can be pried open by overcoming the yieldable engagement of the snap latch arms or fingers 68 within the keeper ferrule 72. When the door 54 is closed, the latch 67 operatively snaps into latching relation within the keeper ferrule "52.

From the magazine, the outer end portion of the strip of staple blanks is fed from the supply roll through a gap '55 (Figs. 3 and 5) in the lower forward portion of the liner wall 33 toward the forward or forming and driving head end of the stapler. For this purpose, the lower forward portion of the liner wall 33 is split and a lower forwardly directed flange portion li provides a ramp for egress from the magazine. At the upper side of the gap it a short flange por tion I8 of the side of the liner wall is turned downwardly and forwardly arcuately as a deflector lip.

Strip guide and anvil structure Adjacent its rear end, the member portion 8| of the body shell flange 38 are received. Forwardly from the tip of the ramp flange H, the member i9 is provided with a longitudinal upwardly opening channel 82 of a width to receive the staple blank strip horizontally therein to be fed forwardly therethrough to the forward or driving end of the driving head portion of the stapler. At its rear end the channel 82 is wider than at its front end and the channel gradually tapers forwardly to a side clearance which closely approximates the total width of the staple blank strip to properly center the strip at the forming and driving station of the machine. However the rear portion of the guide channel is slightly wider so as to afiord greater clearance and thus eliminate any possible binding or resistance to forward movement of the strip as it is drawn from the'magazine.

Inasmuch as the staple blank strip when it comes from the roll in the magazine has a tendency to curl up conformable to its roll curl, means are provided at the entranceor rear portion of the channel 82 to restrain the upwardly curling tendency of the strip and hold it down in the channel. Herein such means comprises 'a roller '83 mounted on a pin or axle 85 supported between the side walls of the housing shell above the rear end portion of the channel 52 and with the periphery of the roller dipping into the channel. By preference the roller is made from an appropriate plastic material such as nylon. Thus, when -'a new supply roll is inserted in the machine and the leading end portion is threaded from the magazine into the guide channel 32, the roller $23 facilitates the threadingcperatio'n by holding the end portion of the strip down in the channel as it is threaded forwardly. It should also be noted that in order further to reduce frictional resistance to forward movement of the strip, the

channel 32 is interme'dia'tely, deepened as best seen in Fig. 3 immediately forwardly from the hold down roller 83 so as to accommodate the downwardly buckled shape of the strip which will persist due to the curled 'set of the material in the roll and until the strip is straightened out adjacent to the forming and driving station as will be more fully described hereinafter.

The sides of the guide channel 82 are defined by a pair of longitudinal flanges orcur bs 85 which are disposed in a common to'p plane.

The anvil and guide member is serves in addition as a bottom reinforcement for the head portion of the machine and for this pur'p'oseis constructed to fit closely between the forward extensions of the side walls 39 and El of the housing shell and to engage against the forward-extension of the lower wall 22 of the housing. Permanent attachment of the block member 9 is effected by means such as a rivet 8i securing the rear channeled portion of the guide block to the lower wall 29 while a plurality of transverse rivets 83 secure the forward portion of the block to the side walls as and 31. t the rear rabbeted extremity of the guide block a rivet 88 secures the laminated flanges Ti and 3% not only to the guide'bloc'k but through the guide block to the lower housing wall 29. Additional attachment to the housing is effected at the forward end portion of the block 1 9 by the interconnection of a respective pressed in longitudinal rib 99 in each of the side walls 30 and 3| in a complementary groove :91 in the respective opposing side of the block. In this way the bottom forward portion of the machine is greatly resistant to impact as will occur repeatin the use cf the hammer stapler. Distribution of impact stress from the bottom of the unit to the side walls 30 and 3-! is implemented by the provision of outward embossments 92 in the side walls 30 and 3! at the place where the rearmost transverse rivet 88 is secured therethrough to afford a space from the adjacent side of the block -79 (Fig. 18') within which an impact stress distribution washer 93 is disposed about the rivet 88 and dimensioned to be in snug edgewise engagement witha shoulder 93 provided by the offsetting of the embossment '92. Thereby impact stresses against the bottom of the block 19 are distributed in shear through the rivet 83 not only to the respective engaged portions of the side walls 36 and 3| but also through the washers 93 to the walls 30and 31 (Fig. 18).

Inasmuchas it is desirable to maintainthetotal weight'of the hammer stapler to aminimumcom sistent with durability, the strip guide and anvil block 19 is formed in its under-surface with a series of cavities '95. However this leaves the underlying portions of the lower wall as of the housing without direct reinforcement by the block against deformation as a result of impacts thereagainst. To remedy this, the cavities are filled with a light weight highly resistant material of which nylon has been found to be quite satisfactory. This material lends itself readily to molding directly into the cavities 9 5 and has high resistance to deformation due to impacts thereagainst while affording a certain amount of cushioning and being exceptionally light in relation to its mass. The plastic cavity fills are identified at 9 L In order to reinforce the bottom wall 29 rearwardly from the guiding and reinforcing anvil block ia-and under the stapleiblank roll magazine, reinforcing means are interposed between the bottom wall :29 and the inturne'd flange .38 (Figs. 3 and 5) and in the present instance comprising a sheet metalireinforcing tube '98 of rectangular cross section and dimensioned to fit snugly in'the space between the bottom wall 29 and the flange 38. At intervals, the top wall of the tube 98 is depressed to provide a reinforcing strut '99 bearing against and secured as by welding to the bottom wall of the reinforcing tube. At its forward end, the-reinforcing tube 98 is secured to the rear end of the block 19 by embracing the rear extension extremity of the block and utilizing the rivet B9 to secure the tube to the block under the flange laminations 1'. and 8 I. "The lower portion of the forward end of the reinforcing tube member 98 is secured by the rivet 85 between the lower wall 29 of the housing and the undersurface of the rear extension of the guide block which for this purpose may be rabbeted or recessed sufliciently to accommodate'the reinforcing tube wallclosely. The forward end portions of the side walls of the reinforcing tube 98 are preferably received-closely between recess portions of the rear extension of the block and the side walls 36 and at, as best seen in Fig. '7.

Staple forming, cut-073 and driving mechanism At the forward end of the anvil block 79, each successive staple blank '20 at the leading end of the staple blank strip reaches the forming, cutoff and driving station in the hammer stapler and means are provided which are responsive to impact against the surface of the object into which a staple is to be driven for severing and driving the leading end staple blank which by this time has been fully formed into the conventional -U-shaped staple form, and in the same action U shaping the next succeeding staple blank. Externally of the machine, such means 9. comprise a striker I (Figs. 1, 2, 3, 4 and The function of the striker I00 is to receive the full force of the impact of a staple driving blow directed against the object to receive the staple by manipulation of the hammer stapler and thereby activate the mechanism which actually forms, shears and drives the staple. For this purpose, the striker I00 comprises a hardened metal member which normally projects below the driving head portion 25 of the machine and is reciprocable in an up and down direction responsive to the impact of a staple driving blow and subsequent lifting of the machine away from the stapled surface. In a preferred form, the striker I00 is made from a suitable heavy gauge sheet steel stamped to form and subsequently hardened and comprising spaced wings or side walls IM lying in assembly at the opposite sides of the driving head end portion 25 of the machine and integrally joined together in one piece by a lower front yoke web portion I02. The lower edges of the striker sides IOI and the connecting web or barI02 are preferably disposed in a common plane and provide a striker surface of generally U-form when the striker is viewed from its lower end.

Each of the striker side walls I M is of a length to extend substantially upwardly along the sides of the head end of the machine and is guided for vertical reci rocation by means com rising a lower anti-friction and guide assembly I 04 and a spa ed upper anti-friction and guide assembly I05.

The lower striker guiding means I04 (Figs. 2

and 4) comprises a pin I01 extending through vertically elongated respective apertures I08 in the side wing portions IOI of the striker and transversely through the driving head end portion of the machine. One end of the pin I01 has an enlarged retaining head I00 while the opposite end of the pin is equipped with a removable retaining disk or collar H0, detachably held in place by means such as a screw III secured into the contiguous end portion of the pin. Supporting bearings for the pin I0! are provided by respective oppositely outwardly projecting hollow bearing bosses I I2 respectively formed integral with the side walls 30 and 3I of the housing shell and disposed in coaxial alignment. Respective rollers II3 are preferably disposed between the ends of the bearing bosses II 2 and the respective adjacent inner sides of the retaining head I05 and the collar H0. The width of the slots I08 is slightly greater than the diameter of the rollers I I3 so that free riding movement of the edges defining the slots on the rollers is permitted during reciprocations of the striker I00. The length of the slots I 08 is so related to the range of desired reciprocal movement of the striker to permit full retraction of the striker during a staple driving impact and subsequent extension of the striker to a desirable distance below the lower wall of the hammer stapler hous ing.

Since in the operation of the striker I 00,there is some tendency toward rocking thereof about the guide pin I01, the upper guide assembly I05 is preferably equipped to afford substantial antifriction relief. Accordingly the guide assembly at each side of the housing may be constructed substantially identical and in each instance comprises a freely rotatable grooved roller I I4 (Figs. 1, 2, 4 and 6) cooperatively related to the upper portion of the respective striker side wall IOI within a vertical upwardly opening slot I I5. The diameter of the bottom of the groove in th spective rollers H4 and the spacing between the vertical edges defining the slots H5 is such as to afford a fairly close relationship but yet ample clearance to permit a very slight rocking of the striker to an extent wherein only one of the vertical edges defining the respective slots II5 engages the roller at any one time.

Each of the rollers II4 (Fig. 6) is freely rotatably mounted on a journal boss I" formed to project outwardly from the respective side wall 39 or 3I, as the case may be, and having a cylindrical journal end portion upon which the roller is freely rotatable. Retention of the rollers H4 is effected by means such as respective retaining studs H8 having enlarged respective base portions I I9 seated in a base enlargement I20 of the respective journal boss II'I providing a socket therefor. The stud II8 projects endwise beyond the end of the journal boss I I I and has an annular groove I2I in the end portion within which a snap-on split retaining disk annulus I22 is secured. In this manner the respective rollers H4 are retained within axial limits by the retaining disk or washer I22 and the bulging stud socket base portion I20 of the tubular journal boss II'I.

As best seen in Fig. 4, the side Walls 30 and 3| of the housing body shell are substantially more closely spaced in the head portion 25 of the device forwardly of the magazine section 21 and above the portions thereof engaging the anvil block I9 whereby to provide substantial clearance between the opposing side wing portions IOI of the striker, and the laterally projecting guide assembly bosses H2 and III on the side walls of the housing maintain the spaced relationship.

In order to reinforce the side walls above the laterally spreadlower portions thereof in the head portion of the device, vertical juncture reinforcing ribs I23 are preferably formed at each side.

Opening rearwardly from the upper portion of the side flange or wing portions It! of the striker are respective similar slots I24, preferably formed in upper rearwardly extending portions of the striker sides and which portions are preferably inset relative to the remainder of the respective striker sides and in parallel planes, as best seen in Figs. 1 and 4. Within the slots li i are engaged respective grooved rollers I25 (Figs. 1, 2 and 6) rotatably carried by opposite end portions of a pin or shaft E21 by which an operating connection is effected between the striker ltd and the internal staple-forming;severing and driving mechanism. To this end, the shaft 52? extends transversely through the rear portion of the head section 25 of the machine and is ac commodated for upward and forward components of movement in arcuate clearance apertures in the respective side walls 30 and 3| of the housing as the shaft I21, responding to actuation by the striker I90, causes an actuating lever 29 to rock about a pivot see (Figs. 2, 3 and 6). The relative positions assumed by the rollers I25 and the shaft I2? in the extended at rest condition of the striker IE5 and the protracted or impact-responsive, staple-driving condition of the striker I00 are indicated in the full line and dot-dash line positions, respectively, Fig. 2. It will be observed that as the roller, shaft assembly I25, I27 moves upwardly and forwardly, the rollers I25 shift forwardly in the respective slots IZQ in the striker, the opposite horizontal edges of which are parallel and operatively engage with the associated rollers I25 in the operations of the device.

By reason of the three-point anti-friction supaesaerc i port of the stri ken. with the supports: or guides tit and I 35 lying in: a. vertical plane. close to the frontof the striker and the operating shaft and roller support E25, t2? lying diagonally in line with the. striking point: substantially rearwardl-y spaced from the support 535-, an advantageous leverage: relationship is provided. results in substantial balancing of striking force stresses due to the-short lower striking lever arm and the relatively long upper driver-actuatin lever arm having asfulcrum the pin I01 which at maximum impact force intervenes between the. striking point and the driver actuating shaft [21.

The forming, severing" and driving unit The side plates I33 and I34 are preferably substantially alike but in complementary relation and formed of the same outline so thatin the assembly while there are differences to the extent that the plate I33 provides the left. side of the unit and the plate I34 provides the right side of the unit all of the structural features are the same. The plates. are secured coextensively in parallel relation by means of a screw 35 securing the lower portions of the. plates together and a screw I37 securing the upper portions of the plates together. Opposin contacting coaxially aperturedv spacer bosses I38 (Fig. 16) space the side plates properly apart at the screw L35, while opposing contacting spacer bosses I39 space the upper portions of the plates apart at the screw 63?. The bosses I38 and I39 are preferably formed integral in one piece with the respective plates. I33 and I34.

Pivotal support for the lever I23 is afforded by a temporary pivot pin I33 supported in respective pivot pin apertures I43 coaxially disposed in the side plates I33 and 34. Clearance for the actuating pin or shaft I2! is afiorded by arcuately shaped respective apertures I II in the side plates i33 and I34, in assembly registering with the apertures i 23 in the respective housing side walls 33 and 35. A bearing aperture I42 in the lever E23 registers with the clearance apertures 14! and affords a sliding bearing fit for the actuating pin or shaft I2I'.

The temporary pivot pin I33 provides a fulcrum for the lever I29 which is disposed forwardly from the actuating shaft axis a shorter distance than the axis of a pivot pin I43 by which the link I3! is connected to the lever I23. It will be observed that the pivot pin I43 is disposed forwardly and upwardly adjacent the forward end of the lever I29 with respect to the pivot pin I33, and that the forward end of the lever is bifurcated so that the link I SI is slidably mounted between the forward end bifurcations of the lever. Through this arrangement, it will be clear that relatively smaller arc of movement of the actuating shaft I2! will effect a relatively longer are of movement of the pivot pin I43 by reason of the differential in the arms of the lever from the fulcrum or pivot pin axis of the lever.

The link I3I projects downwardly and forwardly from the forward end of the lever I29 and is received slidably in a bifurcated head M4 at. the upper end. of the plunger or driving member I32, a pivot pin I45 connecting the link in the head. From this, connection the driving member I32 extends reciprocably downwarcliy within the forward. margins of the. side plates I33. and. I34 of the assembly- As. a result, rock ing movements of the lever I29.- efiected by the strikertfln to carry the rear end portion of the lever upwardly and the forward end portion downwardly causes the driver I-32 to.- be driven. through the transmission medium of the lick I31 downwardly, while reverse rocking of the lever its causes reverse movement. of connected parts.

The driver I32 is guided for vertical. reciprocal movement. between. the forward margins of the side plates I33 and I34. For this purpose the sides of the driver are. provided. with. respective longitudinal keying ribs lei lon itudinally slidably bearinged in respective vertical guide grooves M3 in the opposing faces of the side panels 133 and; i34- (Figs... 16 and 1'1). The construction and relationship is preferably such that the front surface of the driver I32 isdisposedsubstantially flush with the front edges.- of the side panels I33 and I34.

By preference,v the side. plates I33. andv 533 are made from an easily machined, or molded, self lubricating plastic material such as nylon. By the use of such material long, wear-free life for the unit is assured since friction and wear due to friction is reduced to a minimum without need for special lubrication.

view of the impact stress factors involved in the use of the hammer stapler, reinforcement is preferably provided in the upper portion of the side plates I33 and I34, and especially in association with the lever pin #30. For this purpose, metallic reinforcing plates 549 are set flush into the outer faces of the side plates preferably by molding, the reinforcing plates being secured in place as: by means of keying lugs I50 of the. material of the respective side panels in terlocred within respective taper edged interlock apertures IS! in the reinforcing plate. To prcvide: solid bearingsupport. for the lever pivot pin I30, each of the reinforcing plates I43v is provideol with an inturned bearing flange I52 defining the respective bearing openings I40 for the pivot pin. Reinforcement for the bearing flanges IE2 is provided by a metallic reinforcing disk or washer I53 press fitted about each of the bearing flanges and preferably taper-edged as indicated at I54 (Fig. 6) for interlocking with the plastic material of the side panels of the unit. As a result, the respective areas of the side panels I33 and I34 which are subjected to the greatest stress or shock from impact in the operation of the machine, and especially in the areas thereof about the pivot pin I36 are stiffened and reinforced and the pivot pin I30 is supported on a fixed axis relative to the assembly in spite of the inherent tendency of the plastic material to yield in response to an impact thereagainst. On the other hand, operation of the machine is very quiet due to the cushioning and sound deadening effect of the plastic material of the side panels i33 and I34. It will be observed in Figs. 14 and 15 that the upper edges of the reinforcing plates I49 are coincident with the upper edges of the side panels I33 and I34 as are also the front edges of the reinforcing plates coincident with the front edges of the side panels.

When the driver unit is mounted within the head end section 25 of the hammer stapler, the

lower edges of the side panels I33 and I34 are disposed above the forward portion of the channel 82 of the anvil member I9 while the upper edges of the side panels are received under the forward portion of the top wall 28 of the housing shell. The outer faces of the side panels and the flush reinforcing plates Hi9 slidably ppose the inner surfaces of the housing side walls 36 and 3| in the upper forward narrow spacing thereof. The construction and arrangement are such that the driver unit can be slid into position from the front end of the hollow housing shell which is for this purpose arranged to be opened at will.

Support of the driver unit is effected by interengagement of the side walls 36 and 3i and the side panels I33 and I34. For this purpose longitudinally extending respective inwardly projecting interlock ribs I55 (Figs. 2 and 4) in the side walls Bil and 3! slidably engage in complementary longitudinally extending interlock grooves in the outer faces of the side panels I33 and I34 (Figs. 4, 14 and 15).

Releasable retention of the driving unit against forward displacement from the head section of the machine is effected at least in part by the striker guide pin I69 which extends through aligned apertures I58 in the lower portions of the side panels I33 and I34 and through a metallic retaining block I59 which is held removably between the side panels by engagement withthe forward faces of the spacer bosses I38 and with upper and lower retaining bosses I66 formed on the inner sides of the side panels forwardly from the bosses I38 and at the inner sides of the driver guide channels I46. Further retention of the driver unit is effected by the pivot pin I33 which is driven into place and displaces the temporary pin I36 after the driver unit has been inserted fully into the housing and before the striker I66 is assembled with the head end portion of the housing. The end portions of the pin I36 (Fig. 6) extend in thrust bearing relation through bearing apertures IBM in the side wall panels and 3i. Snap rings or washers I3llb on the pin end portions retain the pin against displacement. When the driver unit is to be removed from the machine, the pins I69 and I36 are released and removed.

Front closure and 4mm! gate Further retention of the drive unit within the head section 25 of the housing is effected by means of a releasable hinged gate I6I of generally L-shape adapted to close the forward end A of the housing shell (Figs. 1, 2, 3 and 4). The gate has an upper short leg I62 which overlies the forward portion of the top wall 28 of the housing and has marginal side flanges I63 fitting down around the upper contiguous margins of the side walls 36 and 3! of the housing and terminating at the distal end of the leg I62 in a pair of parallel journal ears I64 which are appropriately coaxially apertured and accommodate a headed attachment hinge pin I65 extending therethrough and through appropriate aligned apertures in the side walls 30 and SI of the housing and the side plates I33 and I34 forwardly of the main portions of the spacer bosses I39 at the inside upper rear portions of the side plates I33 and I34. The hinge pin I65 is quickly removably retained in place as by means of a cotter pin I61 extending through its projecting end opposite the head of the pin. Through this arrangement the pin I65 can be readily removed when it is desired to withdraw 14 the driving unit from the head end of the machine.

A downwardly extending angular front leg I68 of the gate member is of a length to close the front of the machine or at least the front of the driver unit and extends throughout the height of the machine from the top down to the lower face of the forward portion of the bottom wall 29 of the housing. When the gate is to be opened it is swung up about the hinge pin I65 into a position as shown in dash outline in Fig. 2. When the gate is closed, the front leg I68 is held against unintentional opening by a pivoted latch I69. The upper portion of the latch has a journal I76 which is hingedly connected as by means of a pin I'II between a pair of forwardly projecting hinge lugs or ears I12. This enables the pivoted latch arm to swing into and out of latching position as indicated in full and dash outline, respectively, in Fig. 2.

In the latching position, the latch E39 operates to retain the gate member I fiI in closed relation at the front of the hammer stapler by engagement of a pair of rearwardly projecting spaced parallel latching or interlock lugs I73 on the distal end portion of the latch arm with respective contiguous forwardly projecting respective latching interlock or keeper shoulders I13 and IE5 on the side walls of the housing and the side panels of the driver unit at the forward margins of the side walls and panels. The latching flanges or lugs H3 are spaced apart sufficiently to clear the side edges of the front leg of the gate I58 and have upwardly facing preferably concavely arcuate rearwardly and upwardly curving interlock shoulders ill, and the shoulders I'E l and H5 are complementary in radius. Through this arrangement, as will be best appreciated from Figs. 2 and 3, an efficient hooked under relationship of the interlock shoulders is attained which will resist any force tending to swing the gate member outwardly and it will be necessary to swing the latch member 5633 out of latching position before the gate member can be swung to open position. The interlock shoulders We are provided by laterally extending lower edge integral flanges Il s on respective forwardly projecting wing flange portions I'iEl on the respective forward margins of the side walls 36 and 3| of the housing shell. The interlock shoulders I'IE are provided on the lower edges of forwardly extending wing flanges or lugs ISll on the forward margins of the respective side panels I33 and I3 4 of the driver unit.

Retention of the latch member Hi3 against unintentional opening effected by releasable means such as a-yoke-like retainer preferably formed from heavy spring wire having a generally U-shape and including a yoke head portion I 8I engageable about the lower latching head end portion of the latch member. A pair of substantially elongated spring legs E82 extend rearwardly under the guide pin journal bosses II2 inside the side wings Id! of the striker (Fig.

: 4) and then extend upwardly rearwardly of the lower portion of the striker and outwardly of the rearwardly projecting slotted upper portion of the striker and are yieldably anchored under tension by engagement in retaining annular grooves 83 in the respective opposite end portions of the actuating pin or shaft 52? outwardly of the striker-engaging rollers E25 thereon. This affords a multi-advantage relationship since not only are the spring retainer legs I82 thus maintained under resilient tension by engagement i5 under the respective tensioning fulcrums pro.- vided by the bosses IE2 and thus cause the yoke head to be constantly and positively biased rearwaro'ly into firm latch-retaining relation, but the retainer legs. also serve as retainers or keepers for the shaft 523' the rollers I25. By their engagement in the grooves I83 (Fig. 6;) the arms or legs ItZ- are held against displacement in axial direction from the end portions of the shaft I 2'1 and in turn retain the rollers I against axial displacement endwise from the shaft, and by co.-. operation with the rollers 525 retain the shaft in generally endwise centered relation in the ass sembly. Nevertheless, when it is desired to dis assemble the mechanism, the retainer arms I82 can be re lily out of engagement with the shaft, 527 and the shaft displaced endwise from the assembly. An additional advantage of having the retainer arms 5&2 engaging the shaft I21 resides in that as the striker Ifiil is activated upon a staple driving impact and thus moves the actuating shaft fill in its upwardly and for-. wardly arcuate operating movement, the arms I82 are correspondingly flexed forwardly, thus exerting increased retaining tension upon the re-.

tainer member at the very moment when the maximum jarring and centrifugal forces are active tending to swing the latch I39 open unintentionally.

It will be observed that the spring arms I32 of the retainer are of relatively great length and that the tensioning curvature thereof is on a large radius while the respective fulcrum points provided by the bosses IIZ and the respective tensioning points provided by the shaft l2! are spaced a substantial distance apart so that tensioning deflection on the arms I82 is distributed throughout such a length of each of the arms as to avoid concentration of bending stresses and fatigue failure of the spring arms.

Further implementation of the tensioning of the spring retainer results from having the fulcrums afforded by the bosses IIZ offset down.- wardly relative to respective lateral reta ning lugs or ears its at the sides of the lower latching head portion of the latch 69 and engaging under the retainer head end portions of the arms I82. Since the bosses H2 are spaced substantially rearwardly from the latch, substantial tension is developed in a downward and rearward direction in the retainer head l8! in the, full assembly. It will also be observed in Fig, l that the arms I82 of the latch retainer flare or are in divergent relation from the head I8I so that when the latch I 69 is to be opened removal of the spring retainer yoke is easily effected by releasing the legs I52 thereof from the shaft I21 and drawing the retainer forwardly until the retainer ears ltd are cleared and the retainer can be dropped clear of the latch head. Reassembly is, of course, easily effected by a reversal of the steps described for removal of the retainer spring. The upper or distal ends of the arms I52 are preferably provided with return bent terminals I disposed on the forward sides of the legs for finishing purposes and to avoid upstanding sharp edges (Figs. 1, 2 and 6).

In the operation of the hammer stapler, upon the impact of the striker I00 against the surface of the object to be stapled, the driving member I32 is driven downwardly between the front end portion of the anvil I9 and the lower end portion of the gate member IBI which cooperates with the front end of the anvil to provide a staple guideway or driveway I81 (Figs. 3 and 7) down whicha staple is driven after it has been severed by e. driv n m mb r fr m the l ad d of a strip f s ple la into t e upper d of the driveway IB'I. A staple exit hole I38 is provided'by the forward edge of the housing low- 1. all 29 in o pe ation w th e l w r n of the g t membe st p e f ming. s e in nd driving As the driver I32 descends in a driving stroke, a shearing edge E89 at the inner side of the dl'iV-s ing tip of the driver cooperates with a shearing edge I90 at the forward undercut or raked end of the anvil I9 (Figs. 3, 7 and 8) to shear the formed staple from the staple blank strip and the staple is then driven on down through the driveway I81. As the staple is sheared from the strip, it tilts downwardly and with the staple legs swinging rearwardly as is desirable in order to facilitate the shearing action. However to prevent over-tilting, respective downwardly and for wardly sloping tapers or lead-in ramps I9I are provided at suitable distance below and at op-.- posite sides of the shearing edge I90 on the front end of the anvil member and extending for: wardly beyond the shearing edge I90 for engagement by the tips of the staple legs (Fig. 8) not only to limit the tilting of the staple but also to guide and straighten the staple legs forwardly into the driveway I81 after severance of the staple.

It has been found that there is a tendency for the staple legs to escape sidewise from the ramps itI and cause the staples to be upended, sometimes with jamming effect as the driving mem-. bers moves down from the severing position. To eliminate this hazard, means are provided at the outer sides of the ramps I9! providing lateral guide and retainer surfaces for the staple tips. Herein such means comprise integral side walls I92 formed in one piece with the forward end portion of the anvil block at the respective outer sides of the lead-in ramps I9 I. These walls provide shoulders which positively prevent running out of the staple leg tips at the ends of the ramps and assure that the staple tips will move down into the driveway I81.

To define the driveway I8! and provide a guideway for the driving end portion of the driver I32, the forward end portion of the anvil is formed as a central forwardly projecting nose [93 which cooperates at its forward end or tip with flanking, interengaging, rearwardly projecting staple driveway side wall projections I94 on the lower inner portion of the gate member front lee I68 (Figs. 7, 8. and 10). Snug lateralstability interengagement of the driveway walls I94 with the nose portion I93 is effected by 1 ternesting engagement of complementary side front edges of the nose portion I 93 in rounded socket-like vertical recesses or pockets I95 in the r spective sid wa 1 p o ti ns I 4- The up er ends of the. pockets I95 are defined by rigid downwardly facing thrust shoulders I96 opposing upwardly facing thrust shoulders I 96c atthe opposite sides of the nose portion I93 outwardly relative to the staple tip retaining walls I 92. Thereby an internested thrust interlock is provided for transmitting upthrust on the forward end of the anvil to the gate leg I68 and thence through the latch I69 to the housing 2 I.

Th driveway wall surfaces of the wall projections I94 are shaped or tapered inwardly as shown at IIl'I generally conformable to or Go! operative with the lead-in tap rs I I to a driveattests way throat" of a; width substantially equal toth'e spacing between the guide shoulders or surfaces l92" for receiving'andgui'ding' the staple legs downwardly and providing lower guid'e'way for the driving member 132. Spaced'irom the forward tip of theanvilnose' I 9 3 and disposed inwardly frointl'ie wall projections I94 are'res'peotiveguidedrivewayboss portions l98on' the gate member cooperating with the anvil" nose to pro vide' generally channel sh'aped ways? for the? staple" legs and the sides of the member" F82" at the sides of'thedriveway'l 8T; Itwi'll' be observed" that-clearance is'afforde'dbetween the inner'ends of the" lead-in ramps Isl ati910; andfbetwe'en' the adjacent or" innerends" of the guideway bosses i98 at i98a for the rear and forwardcentral projections on the staple heads resulting fromthe severed central connecting webportions by which one" staple bla nk'i's connected'to'the' others in the strip.

When the staple-driving stroke'has' progressed? substantially, the driver" 32" in cooperation" with the'anvil block forward nose portion 193 forms the next succeeding? fiat staple blank into the U-shape* desired for the staple; To this end, the

and the-driver i-GZis provided with a rearwarclly and; downwardly opening vertical forming j channel We" bet'ween' the guide ribs MT thereof and" having downwardly directed rounded forming shoulders 2'89" (Fig. 16); In the downwardiad- Vance of' the driver; the forming" shoulders 2W cooperate with tapered longitudinally or for \vardly'extending spaced, parallel a'xi's forming shoulders 21M on the" upper side edges of the anvil noseportion (Figs: 'T'a'nd 8). As a result; thenext succeeding staple blank'is' formed as an incident todriving of the previously formed staple'on the leading end of the strip".

In order to assure uniform driving of the staples the driving tip'of the driver i'32is formed at" each side with" a concave shoulder [32a g'enera'llyeonformable' to th'e opposinglc'onvex shoul der'of a staple:

Staple hoZdf-do wn and" feed Means are provided operative as an incident to and preferably as aresult. of; motivation: by the staple. forming; cut=off-. andsdriving, member.

l3'2'for feedingthe staple; strip by, staplelunit increments into: driving. -position.. Herein. such means comprise part of a package unit 202 including a staplestripholdingor back lash preventing device and a hold-down device.

As best seen in Figures 3; 11 12 and I3} the staple: feed and hold-down'unit 2112 1580 con'-- structed'? and; arrangedthatl it can lie-inserted into andlremoved from the headend section 2 5" ofthemachine'wvith the driver unit? To this end; the feeder unit-1 comprises a'frame preferably formed as'a oliepiece heavygauge sheet" metal stamping of" generally inverted u -shapecompri's ing. comelementary' spaced si'de wall panels "-203" a forwardly and" downwardly extendin teen arm or lever 2TB. This lever maybe of'iriverted' U- sl'ia'pe in cross section with parallel rear end portions slidabl'y disposed at op-posi side's ofthe lower hdofth'e supporting level 2 8 and providing journals for the pin zile. A torsion spring 21"! yoked" over the reed lever 2le'arid coiled about" the outer ends of'tl'l'e pin 2st tension:

ih'g. arms 2 f2" anchored "against-a transverse ahthe pivot pin 203' and normally biases the reedleve'r'i'h a downward direction. At the same time" the lever ft't'i's blas'ei'i fi o fidllfia'lly' 85371111115 f6!- wardly swung direction by meansof a torsion downwardly opening" rectangular sfdckts'iZlT' complementary to and within which the front ancrrear margins 'ofthds'ide panels insane z'ta; respectively, are adapted to be received in assentbliz'." Fortliispurpose each of the" feeder housing al'ly' nrojectirrg ffon't' marginal "engagement wing" 211; 160th oftl'le' unit assemblies are adaptedto bei'r'lsertedintothe liea'd'sec'tion ortlie machine together. For intereneagement with the side" walls" s'namr 31* of the housing shell ofthe ma= chill-eqsiinllarly asefiectedby means of thelio'u's mg shell-retaining ribs I55 in the longitudinal grooves It? or the driver unit side wall panels;

recessfill complementaryto the retaihingribs' lee-"seas to interengage" retainingly' with said -'=ribs% For additional stability of the feeder unit'iii assembly inthe ni'ac'liinaianlfin"order"tb facilitate-insertion thereofihto the machine, side root flangesiifare provideil on the bottom margins laterally and engage" slidabl'y" upon the side rilis" 85of the anvilrilenib'erfllf.

In the assembled relationship, as best seen in Fig": 3;; an" operative" actuating" relationship isv efiected: betweenan actuating: finger 22'2" pro jecting downwardly" and rearwardly from" the head'portion te l ofthestapledriver member and" a forwardly-prod ecting'fportion of 'thele've'rm'ehi her-2'08 of the feedenunit. Fer thisplirbb'seth'e forwardly projectin'g' portionof the" feeder" u mt leveri 'cfli's formed with a downwardly and-for wardly slantin camedge 223 which irrth'e. fully 75- construction and relationship'is such that when the driver 132 is driven downwardly in a staple driving, cut-oil and forming stroke, the actuating finger 222 acts on the cam surface 223 and swings the feeder motivating lever 288 rearwardly to thereby retract the feeder arm or lever 25d which normally engages behind the formed staple at the leading end of the staple strip. This feeder arm retraction movement is one staple width so that staple-engaging tip prongs 224 on the feeder arm will engage behind the next succeeding staple blank and when the driving member i32 returns to retracted position, and the actuating ringer 222 enters a clearance notch 225 in the upper forward portion of the lever tilt, the lever 206, under the impulse of the biasing spring 2M snaps forwardly to drive the feeder arm lever 2H3 forwardly and thus advance the staple strip one staple blank forwardly.

In order to assure a feeding action or the feeder unit even though something may cause the mechanism of the feeder unit to stick, or if the spring 214 should break, a positive feeding return action is provided for by having a return head or finger or lug 22: at the upper forward portion of the lever 2% above the clearance notch 225 and in a position to be engaged by the upper side of the actuating finger 222 in the retracted position of the drive member. In this relationship, the feeding mechanism must operate in a feeding stroke irrespective of any other factors that might otherwise cause delay or tend to block the feeding action.

Inasmuch as the feeding lever 2 it? must travel rearwardly with frictional engagement of the feeding prongs 22d with the next succeeding staple blank, a holding arm or lever 228 is provided which is pivotally connected as by means of a pivot pin 2223 between the lower forward portions of the side panels 2G3 and 2% of the feeder housing and projects forwardly under the feeder finger or lever 2H; so that holding prongs 236 on the holding lever will engage behind the rear edge of a succeeding staple blank and hold the strip against return movement. The hold-down lever 22% is normally biased to swing downwardly by means such as a torsion spring 231 wound about the pivot pin 229 and having an arm in engagement with the hold-down lever forwardly of its pivot and a torsion arm engaging an anchoring pin 232 spaced rearwardly from the holddown lever pivot between the side wall panels 203 and 2% under the feeding lever 21c during a feeding forward movement or the staple strip, the hold-down lever 22% yields upwardly and then snaps down behind the next succeeding staple blank.

By having the feeder cam lever 268 springbiased forwardly forward thrust pressure is imparted to the driving member I32 through the finger 222 and this avoids striking of the driver shear edge its on the anxil shear edge I90, should there be any play between the plunger or its aligned guideways.

In order to facilitate initial feeding of a staple strip under the feeding unit and then to flatten out the strip as it is fed forwardly by the feeding unit, a flat spring hold-down lever 233 is provided which projects forwardly between the lower margins of the side wall panels 293 and 2M and under the remainder of the feeder unit mechanism including the holddown lever 228 and the feeder lever 2 I O and with the forward end portion thereof projecting forwardly between the prongs 224 and 230 to lie upon and press downwardly against the staple blank 26 in position to be formed.

As best seen in Fig. 3, the rear end portion of the hold-down spring 233 in assembly overlies the deepest portion of the staple strip track 82 in the anvil block and provides a substantial gap between the bottom of the track and the undersurface of the hold-down spring 30 that the leading end of the staple strip can readily be fed forwardly in the track. At the forward end of the track the hold-down spring lever 233 normally tends to engage the bottom surface of the track and thus holds the forward end portion of the staple strip firmly down in the track. Then as the strip runs out to a trailing end dummy blank like the dummy 1) (Fig. 9), the lever 233 assures that the final staple blank as will be formed and driven.

Mounting or" the hold-down spring 233 is effected at the rear of the feeder unit 202 by means such as a rivet 234 which fixedly secures the rear end portion of the strip to a rearwardly projecting horizontal eye or lug formed as an integral angular flange on a vertical spacer and supporting plate 23'! having side edge lugs 238 secured in respective slots 233 in the rear lower portions of the side wall panels 263 and 204. Since the rear portion of the hold-down spring 233 is substantially narrower than the spacing between the side wall panels 263 and 204, the lower margin of the supporting plate 23'! is provided with downwardly extending centering lugs 2&9 which flank the rear end portion of the holddown spring and hold the same against turning about the axis of the rivet 234.

Further interconnection between the feeder unit 282 and the driving unit is effected and a spring bias for normally returning the driving mechanism to the initial or inactive condition thereof is effected by means of a coiled tension spring 241 having one end attached to an anchor pin 242 extending between rearwardly projecting bifurcations 2 53 on the actuating lever I29 of the driving unit. The opposite or lower end of the connecting and return spring 24! is attached to a transverse anchoring pin 264 carried by and between rearwardly projecting vertical parallel ears 245 at the lower portions of the side wall panels 203 and 264 of the feeder unit housing. The cars 2% are provided with appropriate coaxial apertures 2 47 for reception and support of the pin 2%. The spring 24E is tensioned normally to rock the actuating lever E29 clockwise as seen in Fig. 3 and stretches to accommodate counterclockwise movement of the actuating lever 129 in response to actuation by the striker lull when a staple driving blow is struck.

Summary of operation After the combined driving unit and feeder unit have been inserted in the head section 25 of the machine and the gate l 6| swung down into closing and retaining relation to the assembly, and the latch I69 has been locked in place, with the striker I08 also operatively mounted on the machine, the latch retainer spring l8l, I82 also being operatively positioned, the machine is ready for operation. A roll R of staple blanks is placed into the magazine of the hammer stapler and the leading end portion of the roll fed from the magazine under the guide roller 83 into the anvil track 82 and with a prongless starter dummy terminal blank D in the staple driving position. This is accomplished quickly and easily by reason of the anti-friction non-snagging structures that have been described. The door 55 is then closed and the machine is ready for operation.

Z1 Q 2 he miti ls to se the ltmmablan smcemes out Ii atv bottete nsuc eeding-hie. c usivevoaf inela t-h a l sntthelsttinwlllbeli n}. lhon end tiveoeqcuo atelw rom machine n eseeose toieetmatico oithe 94 n mna t. ae atast.. sn tac a staple is e-be driven.

In manipulating the machine it is wieldedthe lmeaelauhamen sl thahandle. 22; is stashed the machin swun at and m hammen ns; e ation aeain the-hob-leoti to be ta ed. the teinem lfleza med :to sllr ke; the ons t, 7

- .le: when l ssen theet' a ihtheliorwardipote t. relativelwshort for: ttheb ttel aisidisoosedin mandala d atribe-beet surfiace While e: bi aenl athlete; harene der of;

the; object; torhe ee eaeea l cularpoi-itionoflthe cf. thecbiee ch isuliflnrecfiive the Q2 imayuoocur when the==ham- 152 111 Witha short hammering This rel-a1 hShih-l:i$-.-.-best.aseem in Figs. 2' l ed It elso belobserved-from;mes 1 and stroke.

I, N p for.- annrea-sombe very readily. cleaige H by -the; simple expedient 0fHsWimgingthegate 6 open This; can-be.- eiiected without the 11. 9 51 filli ll i thefi1atchs 69; swinging the et? on n ndl h nswineinatheagate;op

hinggoes wrongimeitheis the-drivingrmovedrahd repaired on replaced by=the-- simple expedient of opening the gate l6], removing--the-- pigs-J m, 15235 and lfifitand withdrawing-the dr-iver ole units; This-isle. -substantial conven pf .fc rugged; efiicient structural relastaple long, trouble f reeuuseful: service canhe expects flZQII the machine..-

be: effected: i without departing We claim as out. invention: 1 ln comhina tion in: a hamn'lenstapler,- an

elon ated; body-Lcomptising a rear handlasection- V the feeder-unit, theseecan be readily-l 13 hi mfichainismwofzthelpresent harneeundez stoodi that modifications and ads sections; and-call:- otthe sections being n; -,l;;ne;,- said magazine section being di's'-- 22 nosed; close to; the; head; sectionandr including means .foy: reception-pica substantial 1'01]; of: metal staple blanks in .a; continuous: strip, said magazine section including anpassagewayzforwardly. from the; bottom portion theteof intoisaid head section; and means disposed w-nzhinthe). head 1 section in]: severing :and driving; staples fromithe leading; .encl Ofi the staple; strip responsive; to. wielding of the; hammer stapler; 'hammet-elikebfor the staples 2; In, combination in.- a hammerv stapler,-. an elongated-body comprising a rear handle section and; a; from; head: section witltu mtermedl'iate magazinesection; int-ervemng. between 1 the:- ham d'le andairontzhead sections, saidz'magazine seofl tion including/means :fonreoeption of asubstantialxrol'l :of :sheetimetal staple blanks-in aucontinne ous strip and including a passageway forwardly from bottom portion thereot intow sald- =head ;section,-i and means for severing: and driving staples from; th'aiead-ing. end: at the staple -blanl'; strip nesponstve to wielding ofthe. hammer stapler hammenelilzefor driving the staples; said magazine section means including anti-friction H structure.cengageablezby theou-tside of the staple strip roll zto min-imize-ftiotionat 01 abrasion resistanceof the staplablank strip in the-roll to forward-movement oh the staple-stPi-pdnthe ep ora-tion of thehammer stapler;

3*.1In'. coznbinationiin ahammen-staplerr an;- assemblyincluding 3111p clongatedhandle" and" 8:1 driving head sec ticn-zwitlnan' intervening-ymagag zine, section all disposed indorrgitudinal -series; said magazine-section being generally flatten-ed; and of" maximum dimension in a vertical sense; said magazine section having-means therein forsupporting a substantial roll of metal staple blanks vand including a passag e to the driving head: section, andlimea-nscarried by thep'dl'iving head section forsuccessively driving staples from theleading end: ot the staple blank strip substantially square into a surface responsive to Wield ing ,ofthe hammer staple'rhammer-like against, such: surface-01 stapling; saidmagazine section being of substantially greater vertical dimension than; thehandle and including; a juncture area witl'rvth'a handle shaped to accommodate graspingtha-same for short leverage yvielding of the. hammer stapler; thebottonrzofsaid magazine section and: said-juncture area being dlsposed in,

substantialcleara-nce elevation relative tjqthe, lower forwardportionof the driving head. sec: tion. so as to accommodate the :fingers 12 the. usens: hand to avoid striking the same against an aoba'ect being; stapled during; sa-idshort leverage.

wielding of the hammer stapler,

4.- In- 'combinationin a, hammer stapler. an, elongated tubular sheet metal shell body including spaced side-walls and spaced; top and bottom.

hwalls, said body including an elongatedrrean handle section and a relatively. Short front end-a head section with an intervening vertically en! largedmagazine-section closely. adjacent, to. said,v head section, saidmagazine section. having,

means therein for supporting a substantial, roll of sheet metalstaple blanks instrip formto be fedf0rward1yfromthe magazine section into-the Y head section; and means carried by. the :head S8075 tion for driving staples from the vendvof. the strip.

responseto wielding of the hammer stapler.

5. In combination in a hammer stapler, an elongated tubular sheet metal shell body including spaced side walls and spaced top and bottom walls, said body including an elongated rear handle section and a relatively short front end head section with an intervening vertically enlarged magazine section, said magazine section having means therein for supporting a substantial roll of sheet metal staple blanks in strip form to be fed forwardly from the magazine section into the head section, means carried by the head section for driving staples from the end of the strip in response to wielding of the hammer stapler hammer-like, and means carried by the head section and magazine section portions of the bottom wall to reinforce the same against impact deformation in the use of the hammer stapler.

6. In combination in a hammer stapler, an elongated tubular sheet metal shell body including spaced side walls and spaced top and bottom walls, said body including an elongated rear handle section and a relatively short front end head section with an intervening vertically enlarged magazine section close to the head section and substantially closed off from the interior of the handle section, said magazine section having means therein for supporting a substantial roll of sheet metal staple blanks in strip form to be fed forwardly from the magazine section into the head section, means carried by the head section for driving staples from the end of the strip in response to wielding or the hammer stapler hammer-like, and means carried by the head section and magazine section portions of the bottom wall to reinforce the same against impact deformation in the use of the hammer stapler, said reinforcing means comprising an elongated anvil block extending from the magazine section throughout substantially the length of the head section and providing a guideway for the staple blank strip.

7. In a stapling machine including staple forming and driving means, a magazine for a roll of partially formed spaced sheet metal staple blanks comprising substantially coplanar oppositely directed pairs of arms connected by medial narrow spacer and connecting necks in strip form to be fed from the magazine to the forming and driving means by staple blank incremental withdrawal of the strip from the roll, means in the magazine for supporting the roll, and means substantially encircling the roll but having an opening therefrom for passage of the strip from the roll to the forming and driving means, said encircling means comprising an inwardly projecting roll-expansion-limiting and friction-reducing arcuate rib medially opposing the periphery of the roll continuously except for said opening to engage the medial neck connecting portion of the strip at the outer periphery of the roll, said rib having a substantially line-contact engagement ridge opposing the connecting neck medial portion of the strip at the periphery of the roll spaced radially inwardly from the sides of the connecting necks.

8. In combination in a stapling machine, means providing a magazine for a roll of sheet. metal staple blanks in strip form, said magazine comprising a wall substantially encircling the roll and having an opening therefrom for passage of the strip from the periphery of the roll in the use of the strip for stapling purposes, said wall having a rib projecting from the roll opposing surface of said wall and extending in the direction of rotation of the roll for holding the strip at the roll periphery out of contact with the Wall except for engagement with said rib, and a pair of spaced opposing rotary anti-friction plates opposing the opposite sides of the roll and rotatable therewith as the roll rotates in withdrawal of the strip therefrom for stapling purposes.

9. In combination in a stapling machine including staple driving means, a housing providing a magazine for a substantial roll of sheet metal staple blanks having substantially coplanar oppositely extending pointed legs and connected together in strip form, a roll supporting hub structure, said housing having at one side a wall supporting said hub structure and with the hub structure projecting toward the opposite side of the housing, said opposite side of the housing having an opening for insertion of a roll of staple blanks as aforesaid into the magazine onto said hub structure, a rotary anti-friction plate rotatable about said hub structure adjacent to said wall to prevent engagement of the pointed legs at the opposing side of the roll with said wall, a closure for said opening removably mounted on said housing and cooperating with said hub structure to retain the roll rotatably thereon, said closure member having rotatably mounted thereon and removable and replaceable therewith relative to said hub structure a rotary anti-friction plate complementary to said first mentioned rotary plate and opposing the remaining side of the roll in the magazine to prevent engagement of the points of the legs on said remaining side against said closure.

10. In combination in a stapler, a body having a driving portion and an adjacent magazine portion, said magazine portion including means for supporting a roll of sheet metal staple blanks in strip form and having a passage therefrom toward said driving portion for the strip of staple blanks from the roll, means leading from said passage and providing a channel for receiving the strip therein, means within said driving portion for feeding the strip forwardly in said channel for driving staples from the leading end thereof, and a roller located within the body adjacent to said passage and above the portion of the channel adjacent to and leading from said passage to hold the strip down against any tendency of the strip to curl up within said channel.

11. In combination in a stapler, a body having a driving head portion and an adjacent magazine portion, said magazine portion including means for supporting a roll of sheet metal staple blanks in strip form and having a passage therefrom toward said driving head portion for the strip of staple blanks from the roll, means within said driving head portion for feeding the strip forwardly for driving staples from the leading end thereof, a roller located within the body adjacent to said passage and above the path of movement of the strip through the passage to hold the strip down against any tendency of the strip to curl up within said driving portion, and a flat hold-down spring extending forwardly in front of said roller for additionally holding the strip down against any tendency to curl up.

12. In combination in a stapling machine, means for supporting a roll of sheet metal staple blanks in strip form, means providing a track for the staple strip as withdrawn from the roll, a flat hold-down spring supported cantilever fashion at the rear and above said track and aesaezre 25 bearing down'withinfisaid track forstrazightening the strip, a yieldable holding finger "for preventing :retraction of the :strip, and a. feeding lever forstep-hy-step advancing of the strip.

13. In combination in "a stapler, azbodylhaving a. driving :head and means for supplying staples tozsaid .head,. means withinsaidzhead .for driving staples therefrom, .a striker member, means for supporting. and guiding said -fstriker member in :an undeviatingrectilinear reciprocal path gonithe front portion of Sa-id' hBadTtQ move from *a striking-position projecting .below the bottom .ofsaid rhea-d to a higher .elevation in response to staplingimpact against :a, surface to receive a staple, and .means operatively connecting said striker withqsaid staple driving-means so'thaton impactlstroke. movement ofzthe-striker said driving means is actuated to drive astaple.

14. In combination in "a stapling -mach=ine, .'a body including :a housing having an opening therefrom, -a self-contained driving .unit, :a .selfcontained stapleefeeding unit, means separably connecting said units-for operationoftheieeding unit by the driving unit. said units Lbeing removablyinsertabl in said-housing through said opening, and means for 'removably connecting said units in place in saidhousing.

.15. .In combination in 1a stapling machine, a self-contained staple feeding unit including a supporting structure :and -stap'le ieeding structure mounted on said supporting structure for movement aboutian axis; transverse ,to the :directiontof staple feed action of -theieed structure, a housing shell :having'lan "opening there-from.

said :unit being .insertable yinrsaiad housingshell through said opening, :andzmeans for supporting the unit .removably .in-said housing.

.16 In oombinatiomina stapling machine, aseifcontained driver unit, a self-contained feeder unit,-a bodyrcomprisinga housing having an opening therefrom, .said units :being eooperably separably related and insertable to'ge'therthrough said opening, and rib and groove, interconnecting means between said unitszand said'lhousing for supporting said units, in the housing.

17 .;In-.combination 'in' a stapler, "a. body includingia head portion and .an adjacent magazine section, :means for supporting azsupply of staple blanks in said magazinesection, 'sai'dhead portion, havingxa forward :openin'g, an anvil: 's'tructure supported'within the lowerpart of said h'ea d portion, astapleefeedingmnitcomprising a h usingZ -and: staplee feeding means. and a: stapler-feed ing=means actuating al'ever carried by sai-d ihou'sing as aself-contained unit, a'staple driving 'u'r'iit including :a staple driver and a driver-actuating lever'andsupportingpanel-members carrying the driver and driver-actuating lever as a sel-f cohtainedtunit, :said units :being interengag'eable and insertahle :in and removable from the head por tion through said opening'in a position above said anvil, means on said driver for someone said staple4feeding+means actuating lever, a tension spring connecting said d r iver actuati-ng lever Withthe housing of the feeding-unit and serving to imaintain the units in predetermined assembled-relation. as well 'asbiasing the driver actuating-lever'to maintain the driver normally-in retracted position, said driver and said anvil-and said staple-feeding means being cooperably related in assembly for staple-feeding and driving purposes, means carried exte'rnally of said head portion and movable relative to said head ;portion and responsive to substantial impact against a surface to receive a staple, andmeans-operably connecting 'seiid impact-responsive means and said driver-actuating lever formotivatingsaid driver+ actuating lever in opposition to said biasing spring to actuate isaid driver for driving :a staple when said -impact-responsive means moves responsive itofisa-id substantial impact.

:18. In-"combination in :a stapler, a body including a head portion .and ansadjacent inagazine section, means or. supporting .a supply of staple blanks in said magazine section, said head .por-

tion .having a :forward opening, an anvillstructure supported within :the lower part of said head bortion, a staple-feeding :unit comprising a .housing and stapleefeedin'g means and a staple-feedingemearss sactuating lever carried by said housingas .aself-con-tained unit, a staple driving innit including a, staple driver and .av

driver-:actuatingdever and-supporting panel members carrying the driver and driver actuatin-g lever ;as :a :selfecontained unit, ,said units .being interefngageable andl-insertable in and removable from the .rhead-zportiionthrough said opening in a position'abovesaidlanvil,means on said driver for actuatingLsaidlstapleefeedingemeans actuating lever, ;a tension spring connecting said driver actuatinglever withithe housing of the feeding unit and. serving to maintain the units jnpredeterminedyassembled relation well :as biasing the driver-actuating ;-lev.er toztmaintain the driver normally retracted position, said :driver :and said anvil and saidstaple-feeding :means being cooper-ably related in assembly for staple-feeding and driving purposes, :means carried externally of-saidhead portion and movable relative to-saidhead portion and responsive-tosubstantial impact-against, a surface to receive-a staple, means operably connecting said impactresponsive 'meansland said driver-actuating lever for motivating, said driver-actuating lever in oppositionto said biasing spring to :actuate said driver for-drivingastaple when said-impact responsivemeans moves,-responsive:to-said-substantial .impact,-and-a gate.member hinged-1y mounted on theupper partof:said iheadportion and having a part zmovable across said 1 opening and into lcooperative relation to said anvil and said driver to define a staple driveway in whichthe driver is operable.

.19.;In a .seli -contained feeder unit for .a stapling machine, a housing comprising :spaced wall panels, an actuating lever pivotally-mounted between said panels, astaple feed lever pivotally carried by-saidlever andrprojecting-from the housing, .a hold-down lever pivotally carried :loetween-the lower portion of the walls of therhousing-under saidfeed lever, and Ya flat cantilever hold-down finger-like spring supported Joy the lower rear portion of the. housing and extending under said hold-down lever andisaid feed lever,

the. unit being-insertable into a stapling ,ma-

the staplee'feeding means and slidably mounted upon the anvil member by. engagement with said ribs.

. 21. In combination in'a stapler, a, bodyincludmg a head-portion-said head portion being hollov'v and opening forwardly, staple-driving and feeding means removably inserted through said Opening in a front to rear direction, means in the lower portion of said head portion under said staple-feeding and driving means and cooperable therewith for supporting a staple strip in position to be fed to said driving means for driving thereby in the operation of the stapler, a gate member for closing the opening in the head portion and pivotally mounted on the upper part of said head portion and including a portion swingable into and out of cooperative relation to said staple strip supporting means to define with the latter a driveway for staples driven by said driving means, and a latch carried by said gate member and cooperable with said head portion of the housing for retaining the gate member in its closing position wherein said portion of the gate member cooperates with said staple strip supporting means.

22. In combination in a hammer stapler of the character described, a body including a handle portion and a head portion, said head portion being hollow and open forwardly, a selfcontained driving unit within said head portion and having side panels, a gate member swingable into and out or" blocking relation to said opening, and a latch carried by said gate member, said latch having on its lower portion upwardly directed interengagement and thrust lugs and said panels and said head portion having cooperating downwardly directed thrust shoul ders thereon interengaging with said latch lugs for retaining the latch in gate-latching position.

23. In combination in a stapler, a body having a head portion, said head portion being open forwardly and having a hollow interior, stapledriving and feeding mechanism mounted within said head portion and accessible through said opening, a gate member swingably mounted on said head portion and swingable into and out of blocking relation to said opening, and means for holding said gate member in said blocking relation including a yoke member having legs retained in position at the sides of said head portion and a yoke portion extending in retaining relation about the forward portion of said gate member.

24. In combination in a stapler, a, body having a head portion, said head portion having a forwardly opening entrance thereinto, staplefeeding and driving means within said head portion and accessible through said entrance, a

gate member swingably mounted on the upper,

portion of said head portion, a striker movably mounted on the exterior of said head portion. means operably connecting the striker with said staple driving and feeding means and including a shaft movable arcuately upwardly and forwardly in the operative movement of the striker, and a spring retainer yoke member retainingly cooperating with said gate member and having resilient legs connected with said shaft so that on the movement of said shaft upwardly and forwardly said legs are stressed to increase the gate-retaining action of said yoke member.

25. In combination in a stapling machine, an anvil structure for receiving a strip of metal staple blanks for successive driving of staples from the end of the anvil, said anvi1 end having a shearing edge, a driving plunger having a shearing edge cooperative with said anvil shearing edge and a staple-engaging and driving tip, said anvil structure having lead-in cam surfaces spaced below said anvil shearing edge for engagement by'the tips of the staple during shear-' ing tilting thereof to lead the staple tips into alignment under the plunger, and means on and rigid with the anvil structure and projecting forwardly at the outer sides of the lead-in cam surfaces providing lateral guide surfaces for the staple tips to prevent endwise running off of the staple tips from said lead-in cam surfaces, said run-off preventing projection means and said cam surfaces being free from joints at their juncture.

26. In a metal staple driving machine wherein a strip of staple banks is fed to a driving station for successive cut-off and driving of staples from the leading end thereof, an anvil member formed as a one piece block including a shearing edge cooperable with a complementary shearing edge on a driving plunger, lead-in taper surfaces spaced below said shearing edge to guide the staple tips back into alignment with the plunger after shearing, and forwardly projecting wall portions formed in one piece with the anvil member at the respective outer sides of said lead-in taper surfaces to prevent spreading of the staple legs beyond said outer ends of the taper surfaces.

27. In combination in a stapler, a body having a driving head and means for supplying staples to said head, a reciprocabie driver in the forward part of said head, a lever pivoted intermediate its ends in the upper part of head and extending rearwardly above the driver, a link connecting the forward end of the lever with the upper portion of the driver, a striker member, means for supporting and guiding said striker member in an undeviating rectilinear reciprocal path on the front portion of said head to move from a striking position projecting below the bottom of said head to a higher elevation in response to stapling impact against a surface to receive a staple, means operatively connecting the upper portion of said striker to said lever rearwardly from the lever pivot and operable in response to stapling impact movement of said striker to pivot the lever for moving said driver in a staple-driving stroke, and a tension-type return spring attached to the rear end portion of said lever and to a stationary anchorage and normally acting to return the lever and the striker and thereby the driver to an inactive relation after the impact pressure is relieved from said striker.

28. In combination in a staple driving machine, means providing a housing, said housing having an opening thereinto, an anvil structure in the lower portion of the housing adjacent to said opening, a driver unit including a reciprocable driver and means accessible through said open ing providing a guideway for the driver above the forward end of the anvil to direct the driver into staple-driving relation forwardly of the anvil, and a removable closure for said opening including means projecting from the inner face plane thereof and cooperating with anvil to provide a staple driveway and a supplementary driver guideway operatively aligned with the guideway above the anvil.

29. In combination in a stapling machine, a housing having an opening thereinto from the front, an anvil structure in the lower portion of the housing adjacent to said opening, a driver for successively driving staples from the forward end of'the anvil, and an openable gate for said opening having means projecting inwardly from the inner face thereof and interposed in thrust interlock cooperation with said anvil structure and defining with said anvil structure a driver and staple guideway.

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