US2896214A

US2896214A - Wire staple handling apparatus

Info

Publication number: US2896214A
Application number: US603967A
Authority: US
Inventors: Theodore M Wright
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-08-14
Filing date: 1956-08-14
Publication date: 1959-07-28
Anticipated expiration: 1976-07-28

Description

July 28', 1959 T. M. WRIGHT WIRE STAPLE HANDLING APPARATUS 9 Sheets-Sheet 1 Filed Aug. 14. 1956 ATTORNEY i l N M July 28, 1959 T. M. WRIGHT WIRE STAPLE HANDLING APPARATUS 9 Sheets-Sheet 2 Filed Aug. 14. 1956 6 5 I 2, \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\A m 2 4 4% 1 WM I y mi m x 0 Q "a 4 a. 1 7 6 0 A :WV .11 A fl m l e a I 1 y 0 A A R T .A... v u w c. fl i fl T. M. WRIGHT WIRE STAPLE HANDLING APPARATUS July 28, 1959 Filed Aug. 14. 1956 9 Sheets-Sheet 5 T. M. WRIGHT WIRE STAPLE HANDLING APPARATUS July 28, 1959 9 Sheets-Sheet 4 Filed Aug. 14. 1956 p a g IN VEN TOR. Headare M Mzfif AZTOKMY.

July 28, 1959 I 1-. M. WRIGHT 4 wms STAPLE HANDLING APPARATUS Filed Aug. 14. i956 9 Sheets-Sheet 5 IN VEN TOR.

Yfimdore M M131 BYZ 2 ATTDHVEYY July 28, 1959 T. M. WRIGHT 2,896,214

WIRE STAPLE HANDLING APPARATUS Filed Aug. 14. 195s 9 Sheets-Sheet e IN V EN TOR.

ATTORNEY T. M. WRIGHT WIRE STAPLE HANDLING APPARATUS July 28, 1959 9 Sheets-Sheet '7 Filed Aug.- 14. 1956 ATTOFACEY 1959 T. M. WRIGHT I 2,896,214 WIRE STAPLE HANDLING APPARATUS Filed Aug. 14. 1956 9 Sheets-Sheet. a

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YZam'omM M15152 AZYURIVEX July 28, 1959 T. M. \INRIGHT 2,896,214

WIRE STAPLE HANDLING APPARATUS IN V EN TOR.

AI'IURIVEX nite This invention relates to wire staple handling apparatus, and more particularly to apparatus for forming and securing wire staples to the edge of a sheet of material which may, for example, be the edge of a paper box.

Wire staples of the general type to which this invention relates are illustrated in US. Patent 1,825,140 issued to K. F. Berthold and in US. Patent 2,138,495 issued to A. J. Lewis. The staple, itself, is in the form of a length of wire bent into a generally U-shaped configuration with a shoulder formed in each leg of the U.

In the prior art machines, the U-shaped staples are formed in a vertical plane, and the ends of the U are forced through the sheet member to which the staples are applied adjacent to the edge of the sheet. Thereafter, certain members sweep across the edge of the sheet member to bend and fold the staples over the edge. In these machines, the sheet member itself must supply the counter force which is applied to the staple for cooperation with the sweeping members in effecting the folding of the staple. Thus, the sheet member must be sufiiciently strong to withstand the strain necessary to supply such bending force.

The primary object of the present invention is to provide an improved apparatus for forming and applying wire staples to the edge of a sheet member, which apparatus will be free from the aforementioned difiiculty.

More particularly, it is an object of the present invention to provide improved wire staple forming and applying apparatus as set forth wherein no strains are imposed upon the sheet member in effecting the seeming of the staple thereto.

It is a further object of the present invention to provide improved drive means for apparatus of the type set forth.

Yet another object of the present invention is to provide an improved, selectively engageable, automatically disengageable clutch which, while particularly useful in apparatus of the type set forth, is of wider and more general usefulness.

In accomplishing these and other objects, there has been provided, in accordance with the present invention, wire staple forming and applying apparatus having means for feeding in and cutting off a desired length of wire from which a substantially U-shaped staple is formed in a horizontal plane. The horizontally disposed staple is then moved to a bending and applying position where the loop portion of the staple is held firmly. The ends of the legs are next bent to an angle of substantially 90 with respect to the plane of the body of the staple. The bent legs are fully supported and pushed through the edge of the sheet to which the staple is to be affixed. While the loop portion of the staple is held firmly, the leg ends extending through the edge of the sheet are bent, first back toward the edge of the sheet, and then over the edge to wrap around the sides of the loop portion. The loop'portion of the staple is held firmly throughout the bending operation. At no time is the strength of the sheet member relied upon to assist in the bending operation.

The invention itself, both as to its organization and 2 method of operation, as well as additional objects" and ad= vantages thereof, will be understood more readily from the following description, when read in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view, with one side panel open to show the interior mechanism, of one form of stapling machine constructed in accordance with the present invention,

Fig. 2 is a front elevational View, partly in phantom and partly broken away, of the apparatus shown in Fig. 1,

Fig. 3 is a sectional view taken along the line 33 of Fig. 2, and viewed in the direction of the appended arrows, i

Fig. 4 is a partial sectional view taken along the line 4--4 of Fig. 3 and viewed in the direction of the appended arrows,

Fig. 5 is a perspective view of the staple-forming por tion of the apparatus of Fig. 1,

Fig. 6 is a perspective view of the staple clincher assembly of the apparatus of Fig. 1,

Fig. 7 is a perspective view of the staple holding and leg bending assembly,

Fig. 8 is a detailed perspective view of the staple holding die of the assembly shown in Fig. 7,

Fig. 9 is a detailed perspective view of the staple-wire cut-elf mechanism,

Fig. 10 is an exploded view of the cams which effect the operation of the apparatus of Fig. 1,

Fig. 11 is a pictorial flow diagram illustrating the forming of the staple and its movement into engagement with the holding die shown in Fig. 8,

Figs. 12, 13 and 14 are detailed views, partly broken away and in section, illustrating the progressive steps of bending the legs of the staple and thendriving the bent legs through the sheet member,

Figs. 15, 16 and 17 are detailed views illustrating the progressive steps of clinching the staple over the edge of the sheet member,

Fig. 18 is a view showing a completed, clinched staple secured to a sheet member,

Fig. 19 is an elevational view of a once-around clutchbrake mechanism in accordance with the present invention for driving the shaft carrying the cams of Fig. 10, the clutch being shown in the disengaged condition,

Fig. 20 is a view similar to. Fig. 19, but showing the clutch in its engaged condition,

Fig. 21 is aside view of the clutch, and

Fig. 22 is an enlarged, detail view. showing the wire clamping mechanism.

Referring, now, to the drawing in more detail, there is shown, in Figs. 1 to 3, a front mounting panel 2, a; base member 4 and a rear mounting panel 6. Each of these members is made of suitable metal of sufiicient thickness and strength to support, during operation, the several elements carried thereby. Extending between the front panel 2 and the rear panel 6 at an elevation somewhat above the center, there is a main brace and a horizontal mounting bar 8. Also extending between the two panels 2 and 6, and journalledtherein, is a main camshaft 10;

At the top of the front panel 2 is a bracket 12 which carries a supply spool'14 of wire 16 from which the staples are to be formed. A guide member 18' leads the wire from the, spool 14 to a feed tube 20 which, in turn, leads the wire 16 to a wire feed mechanism 21 (Fig. 2

Mounted on the upper half of the front surface of the front panel 2 is a staple holding and leg bending subassembly 22. This subassembly is shown inmo're detail in Fig. 7. The subassembly 22 is driven by a. lever 24 which is coupled to the subassembly 22 lbyfa connecting link 26. The lever 24. is pivotally mounted on a' stud 28 carried by a supporting boss 30. The: boss 30 is secured to the rear surface of the front panel 2. The lever 24 extends through a suitable opening 32 in the panel 2.," The to the anvil.

end of the lever 24 opposite from the link 26 is connected, by a second link 34, to a cam follower arm 36. The cam follower arm-36 is pivotally carried bya suitable stud extending from a boss 38. A tension spring 40, coupled between a stud 42 on the lever 24 and an anchor eye 43 in the base member 4, provides the necessary return force for the reset operation of the subassembly 22. The subassembly 22 includes two main moving members which will be described more fully hereinafter. These two moving members are'coupled, respectively, to the driving link 26 by a pair of connecting

links

44 and 46 and a pin 48 which extends through and couples together the

links

44, 46 and 26. Selective operation of the two aforementioned moving members is effected through engagement of a cam follower extension, which projects rearwardly from'the pin 48, and a cam member 50.

Below the subassembly 22, and extending through the front panel 2, is a staple clinching subassembly'52. This subassembly is shown in more detail in Fig. 6. Some of the moving parts of the subassembly 52 are operated by a first lever 54 which is shown broken away in Fig. 3. The lever 54 is pivotally carried by a boss 56 which is, in turn, mounted on the front panel 2. A link 58 conples the lever 54 to a cam follower arm 60. Others of the moving parts of the subassembly 52 are operated through a linkage including a cam follower arm 62, a link 64, a crank 66 on a rod 68, and a pair of coupling links 70 and 72. A tension spring 74, extending between the crank 66 and an anchor eye 76 on the base member 4, provides the necessary return force to reset that portion of this subassembly which is operated by the last mentioned linkage. A similar tension spring 78 is coupled between the follower arm 60 and an overhead anchor eye 80 and supplies the necessary restoring force for that portion of the subassembly operated by the lever 54.

Mounted on the side of and supported by the horizontal mounting bar 8 is a staple forming subassembly 82. This subassembly is shown in more detail in Figs. 4 and 5. The moving parts of the subassembly 82 are operated by a link 84 coupled to one leg of a bell-crank 86 (see Fig. 4). The bell-crank 86 is supported on a boss 88 mounted on the mounting bar 8 and is driven through a link 90 coupled to a cam follower arm 92 (see Figs. 2 and 3). The cam follower arm 92 is reset to its normal or rest position by a pair of springs 93 which connect it to a pair of fixed pins on the rear panel 6.

Associated with the staple forming subassembly 82 is a wire holding finger 94 (see Figs. 2, 3 and 4). This finger 94 holds a severed length of wire in position to be formed into a staple by the staple forming mechanism. The finger 94 is moved into and out of operating position by a slide block 96 which is driven by a link 98 coupled to a crank lever 100. The crank lever is, in turn, coupled by a link 102 to a follower arm 104 (best seen in Fig. 1). slide block 96 is guided in its motion by sliding engagement with a guide rod 106.

constituting an intermediate mechanism, in that it is physically a part of the clinching subassembly 52 but operates in association with the staple forming subassembly 82, is a staple forming anvil 108 (see Figs. 3, 4, 6 and 11). The anvil 108 is arranged for slight vertical movement for a purpose presently to be set forth. To accomplish this, the anvil 108 is provided with a depending leg 110 which is provided with a recess 112. A stud 114 carried by a lever 116 is nested within the recess 112. The lever 116 is pivotally mounted on a boss 118 and is coupled by alink 120 to a cam follower arm'122. Operation of this linkage provides a slight amount of vertical motion As was previously mentioned, the wire 16 is fed. through the feed tube 20 to a. wire feedmechanism21. -This mechanism is shown in Fig. 2. A cam follower arm 124 carries a large 'sector gear 126. A biasing spring 128 The gear 126 and its associated mechanism. The sector gear 126 is positioned to engage a first spur gear 130 which, in turn, engages a second spur gear 132. The spur gears 130 and 132 respectively carry

smooth wheels

134 and 136 for rotation therewith. The diameter of the wheels 13 4, 136 is substantially equal to or slightly less than pitch diameter of the associated gears. The lowermost gear 130 is mounted on a fixed stud 138 for rotation about a fixed axis. The other gear 132, however, is mounted for rotation about a stud 140 the axis of which may be slightly shifted. The stud 140 is an eccentrically disposed extension from the end of a larger stud 142. The axis of rotation of this larger stud is fixed. A crank member 144 is keyed to impart a slight rotation to the stud 142, thereby slightly shifting the axis of the smaller stud 140.

The crank 144 is normally biased in a counterclockwise direction (as viewed in Fig. 2) by a spring 146. However, the crank 144 is constrained in a direction to oppose the biasing force by a pivoted plate member 148 having a lip 150 (see Fig. 9). The lip 150 carries an adjustable screw stop pin 152 which engages a tang 154 on the crank 144. The plate member 148 is pivotable about the axis of the stud 142 under the control of a link 156. The link 156 is connected to be driven by a cam follower arm 158 which is biased clockwise (as viewed in Fig. 2) by a spring 159.

Positioned above the lip 150 of the plate member 148 is a wire clamp actuating member 160. The member 160 also includes a tang which extends over the lip 150 and carries an adjustable screw stop pin 161 the lower end of which cooperates with the upper surface of the lip 150. The member 160 is biased by a spring 163 in a counterclockwise direction (as viewed in Fig. 22) about an axis defined by a pin 162. The rotational motion of the member 160, under the influence of the biasing spring 163, is limited by the engagement of the pin 161 with the upper surface of the lip 150. However, the pin 162, which determines the axis of rotation of the member 160, is keyed to rotate with the member 160. This pin 162 has an extension which has a flattened face 165 on the lower side. One side of the flattened face of the pin 162 engages a wire clamping rod 164. This rod 164 extends through a suitable opening in the base of the wire feed subassembly to rest upon the upper surface of the wire 16. A backing block 166 is positioned to engage the opposite side of the wire from the rod 164. When the member 160 is allowed to be rotated slightly in a counterclockwise direction (as viewed in Figs. 2 and 22), the flattened face 165 of the pin 162 forces the rod 164 downwardly to clamp the wire 16 between the lower end of the rod 164 and the backing block 166.

Whenever the follower arm 158 is operated by its associated cam 168 (see Fig. 10), the plate member 148 is pushed upward by the link 156. A slight amount of play or lost motion is included in the movement of the lip 150 between the two

tangs

154 and 160. The initial upward motion of the pin allows the crank 144 to rotate slightly under the influence of the spring 146. This causes a shift in the axis of the upper gear 132 and, hence, of the associated wheel 136. The direction of the shift in the axis of the wheel 136 is such as to bring the wheel 136 closer to the other wheel 134. The magnitude of the shift in the axis is limited by the length of the gear teeth on the two

gears

130 and 132. The gear teeth never become completely disengaged. When the two wheels are shifted provides the necessary restoring force for h sector 7 into closer proximity, the wire is clamped between them.

Further upward movement of the lip 150 brings it into engagement with the lower end of the screw pin 161 to produce a clockwise rotation of the clamp actuating member 160 (as seen in Figs. 2 and 22) against the force of its biasing spring. This clockwise rotation of the member 160 releases the pressure on the rod 164, thereby unclamping the wire at that point. I

In the condition thus established, the arm 124 carrying the sector gear 126 may be actuated by its associated cam 170 (Fig. Operation of this arm 124 causes the two

spur gears

130, 132 with their associated

wheels

134, 136 to be rotated. Since the Wire 16 is pinched between the two

wheels

134, 136, a rotation of the wheels causes the wire to be advanced. The excursion of the sector gear 126 and the diameters of the two

wheels

134, 136 measures out a predetermined length of wire.

After the measured length of wire 16 has been advanced, the cam 168 reaches a contour, with respect to the cam follower 172 on the arm 158, which first allows the plate 148 to reestablish a clamping of the wire between the rod 164 and the backing block 166, and then to disengage the

wheels

134 and 136 from the wire. However, simultaneously therewith, the arm 158 operates to also cause the measured length of wire to be cut off. For this purpose, a wire cutting knife 174 (Fig. 9) is slidingly mounted in a guide block 176. The knife 174 is driven forward to shear the wire, by actuation of a bell-crank driver member 178. The bell-crank driver member 178 is coupled to the arm 158 by a link 180. This may be most clearly seen by reference to Fig. 9. A spring 182 applies the necessary restoring force to the knife.

At the time that the measured length of wire is cut off, that measured length is positioned across the staple forming subassembly 82, ready to be formed into a staple. In describing this operation, particular reference will be made to Figs. 4, 5, 6 and 11.

It Will be remembered that a staple forming anvil 108 was described as a part of the clinching subassembly 52 but designed to be functionally a part of the staple forming subassembly 82. This anvil 108 was described as I being movable slightly in a vertical direction. This anvil member 108 is carried in a base block 183. At the time that the measured length of wire is cut off, the anvil 108 is in its uppermost position and protrudes slightly above the surface of the base block 183. The wire rests on the base block 183 adjacent the end of the anvil 108. The finger 94 is moved to its lowermost position and holds the severed length of wire 16 in. the position just described.

The remainder of the staple forming subassembly includes a mounting bracket 184 by means of which the subassembly is secured to the mounting bar 8. It also includes a pair of side guide blocks 186, a slide member 188, and a pair of top guide plates 190. The slide member 188 is coupled to and driven by the link 84, in the manner described above. The forward end of the slide member 188 is provided with a notch 192 which is shaped complementarily to the anvil 108, that shape being the desired contour of the staple to be formed. In this case, the staple 193 will be given substantially a U-shaped configuration with a shoulder part way down each leg of the U. Upon being driven forward by the link 84, the slide member 188 engages the cut length of wire and bends it around the anvil 108. The forward motion of the slide member 188 is continued until the wire is formed firmly between the outer surface of the anvil 108 and the complementary curve of the notch 192. The base of the notch is provided with a further recess 194 to accommodate the end of the finger 94 which continues to hold the wire until the staple 193 is completely formed.

When the staple 193 has been completely formed, as just described, the finger 94 is retracted by operation of its operating cam 1196. in cooperation-withits associated follower arm 104, At the same time, the anvil 108 is. retracted or lowered below the surface of the base block 183,by the cooperative action of the follower am 122 with its associated. cam 198. During the time that the finger '94. is being raised and the anvil 108 is being lowered, thecam follower arm 92 encounters a' momentary dwell on the surface of its driving cam 200. After the finger 94 and the anvil 108 have been retracted, the earn 200- again rises, thereby continuing the forward motion of the slide member 188. The slide member 188 then carries the newly formed staple 193 forward to the staple holding and leg bending subassembly 22.

Reference is now made to Figs. 7, 8 and 12 to 14. The subassembly 22 includes a staple holding block 202 (shown most clearly in Fig. 8) secured to a rear slide plate 204. This constitutes one of the twormain moving members to which previous reference was made. The rear slide plate 204 is coupled, through a stud 206, to the previously mentioned link 44. The rear slide plate 204 is held on a submounting plate 208 by a pair of side guide bars 210. A pair of spacer bars 212 are positioned in front of the bars 210 and are, in turn, overlaid by a pair of front guide bars 214. A front slide plate 216 is positioned for operation in the recess defined by the two front guide bars 214.

Between the front slide plate 216 and the rear slide plate 204 there is positioned a pair of separable jaw members 218. The lower ends of the jaw members 218 embrace the lower end of the staple holding block 202. The front slide plate 216 is coupled, through a stud 220, to the aforementioned link 46. The staple holding block 202 is contoured to conform to the shape of the staple 193. The lower end of the staple holding block 202 is undercut by an amount just sufficient to embrace the staple 193 as the slide member 188 of the staple forming subassembly 82 pushes the staple forward. When the staple 193 is thus moved forward and seated around the undercut shoulder of the block 202, the ends of the legs of the staple extend beyond the front edge of the block 202 as shown in phantom in Fig. 8. Spring biased guide clamps 219 carried by the forward ends of the guide blocks 186 (Figs. 4 and 5) serve to guide the ends of the staple 193 into proper position with respect to the staple holding block 202.

As previously mentioned, the lower ends of the jaw members 218 embrace the end of the block 202. As may be seen in Fig. 12, this arrangement leaves a small horizontal opening through which each leg of the staple 193 may protrude. The body of the staple is firmly held between the block 202 and the jaws 218. In this condition, a cam 222 on the cam shaft 10 causes the cam follower arm 36 to be moved in a direction to start the link 26 in its downward motion through the associated interconnecting linkage. It will be recalled that a pin 48 extends through the lower end of the link 26 and through the

links

44 and 46 to a cam follower (not shown). The cam follower on the pin 48 engages a first cam surface on the cam 50. The angle of the first cam surface is such that it is substantially normal to a line drawn from that surface to the stud 206 which connects the link 44. to the rear slide plate 204. The initial downward motion of the link 26 then causes no corresponding motion of the rear slide plate 204. However, substantially all of the initial downward motion of the link 26 is transferred to the front slide plate 216 through the link 46 and its connecting stud 220. a

The rear surface of the front slide plate 216 is provided with a pair of parallel channels 224 which are aligned with and are of a dimension to receive the ends of the legs of the staple 193. In Fig. 8, it may be seen that the forward surface of the block 202 has a pair of guide projections 226. These projections 226 also fit within the channels 224 and serve to assure proper alignment of the front slide plate 216 with respect to the staple.

As the front slide plate 216 is driven downward by the operation of the link 26, the lower end thereof engages the extending legs of the staple, bending them downward over the edge of the embracing ends of the jaw members 218 (see Fig. 13). Thus, the ends of the legs of the staple are bent at right angles to the main body or loop portion of the staple. As the front slideplate continues its downward motion, the bent legs of the staple are enclosed in and supported by the channels 224 on three sides and by the faces of the jaw members 218 on the. fourth side.

It will be noted that the lower ends of the jaw members 218 meet at the extreme ends, then taper away from each other to about the place where the wire of the staple 193 is engaged. There, a small horizontal step 228 is formed. It is over this step 228 that the legs of the staple are bent downward. It will also be noted that the lower end of the front slide plate 216 has bevelled corners. As the front slide plate 216 continues its downward movement,

the bevelled corners engage a pair of pins.230 which protrude from the front face of the jaw members 218. This engagement causes the jaw members to be separated somewhat against the force of a spring 232 which acts on a pair of studs 234 to normally biasthe two jaw members 218 together.

As the jaw members 218 are separated, the steps 228 are moved out from under the legs of the staple 193, as shown in Fig. 14. At this point, the .cam follower on the pin 48 will have reached the end of the first cam surface on the cam 50. The second surface on the cam 50 permits a small simultaneous movement of both the front slide plate 216 and the rear slide plate,204. This small movement places the lower end of the front slide plate 216 and-the ends of the bent legs of the staple 193 in engagement with the surface of a sheet member 236 to which the staple is to be attached.

The link 26 then continues its downward movement. This continued movement brings the cam follower on the pin 48 into engagement with a third surface on the cam 50. This third surface is perpendicular to a line drawn from that surface to the center of the stud 220 on the front slide member 216. Since the front slide member has reached the limit of its downward movement, the continued movement of. the link 26 is substantially all transferred to the rear slide plate 204. .This motion results in a corresponding downward motion of the staple holding block 202. The motion of the block 202 forces the ends of the staple through the sheet member 236. It will be remembered that the bent ends of the staple legs were embraced by the closely fitting walls of the channels 224. The open face of the channels 224 is closed by the tapered ends of the jaw members 218. Thus, the ends of the legs are completely supported during the initial descent of the block 202. Accordingly, considerable pressure may be applied to force the ends of the staple through the sheet member 236 without the likelihood of having the legs buckle. The complete downward stroke of the block 202 firmly seats the loop or body portion of the staple in contact with the upper surface of the sheet member 236 with the full length of the bent legs extending through and below the sheet, as shown in dotted lines in Fig. 14. When the staple is thus seated on the sheet member 236, the shoulders on the legs of the staple will lie at the edge of the sheet.

Particular reference is now made to Figs. 6 and 15 to 18. Fig. 6 shows some of the details of the structure of the staple clinching subassembly 52, certain of the parts having been broken away for clarity of detail. On a base guide block 238, there is positioned an upper guide block 240. Adjacent the guide block 240 may be seen the base block 183 which carries the anvil 108. The guide block 240 is provided with a centrally positioned recess 242 which is contoured to match the contour of the staple holding block 202 of the subassembly 22. A spring biased staple ejector 244 extends into the recess 242. A guide channel 246 in the block 238'houses and guides a first clincher arm 248. The clincher arm 248 moves in a vertical plane which makes an angle of about 45 with front panel 2. It is operated by a bell crank 250 which is coupled to the link 70. This link is connected through the previously described rod 68 and associated crank 66 and link 64 to the carnfollower arm 62. A cam 252 on the cam shaft drives the arm 62.

A guide channel 254 similar to the guide channel 246 but on the opposite side of the block 240 from the channel 246 houses and guides a second clincher arm 256 similar to the clincher arm 248 (see Fig. 4). This second 8 clincher arm 256 is also coupled, through a bell crank 258, to its driving link 72.

The base guide block.238 has a recess 260 in its lower portion in which is mounted a lever 262. The lever 262 is pivotally mounted on a bolt 264. The forward end of the lever 262 carries a pair of front leg-bending arms 266. The upper end of each of the leg-bending arms 266 bears against a cam member 268. The other end of the lever 262 carries. a cam follower 270 which engages a cam surface on the end of the lever 54. The lever 54, it will be recalled, is connected, through a link 58, to a cam follower arm 60. The arm 60 is, in turn, driven by a cam 272 on the shaft 10. Directly coupled to the lever 54 adjacent to the cam surface thereon is a pair of rear legbending arms 274.

When the staple holding block 202 is moved downward, it fits snuglyinto the recess 242 in the upper guide block 240 and continues its downward motion until the staple 193 is held embraced on two sides by the undercut end of the block 202, on a third side by the walls of the recess 242 and on the fourth side by the upper surface of the block 238. With the body of the staple thus securely held, the cam 272 starts the forward end of the lever 54 in an upward motion. This motion is accompanied by a corresponding upward motion of the front leg-bending arms 266. However, the upward motion of the arms 266 is modified by the cam members 268 to introduce a rearward component to the motion of the upper ends of the arms 266. This motion is illustrated in Fig. 15 where it may be seen that the arms 266 engage the depending legs of the staple 193, bending those legs back on the main body of the staple along straight paths or lines and snugly against the lower surface of the sheet member 236, as shown in dotted lines in Fig. 15.

While the arms 266 are bending the legs of the staple backward, the rear leg-bending arms 274 are moved in position to become operative. The continued motion of these arms 274, as shown in Fig. 16, causes the ends of the arms 274 to engage the now backwardly extending legs of the staple 193. These legs are then bent upwardly over the edge of the sheet member 236 and adjacent to the shoulders of the staple as shown in dotted line in Fig. 16. As these arms are retracted, the

clincher arms

248 and 256 are moved toward the front, but at the aforementioned 45 angle. A cam surface in the guide channels 246 and 254 first allows an initial horizontal motion of the clincher arms, and then causes a downward component to be added to the motion. When these clincher arms move in this manner, they extend into suitably provided slots 276 in the staple holding block 202, carrying the ends of the legs of the staple back over the shoulders in the staple and then downwardly to clinch those ends into or against the upper surface of the sheet member 236. This movement is shown in Fig. 17 and results in a staple attached securely to the edge of the sheet member 236 as shown in Fig. 18. When the ends of the staple 193 have been clinched, the staple holding block 202 moves upward, releasing the staple. The spring biased ejector 244 pushes the staple out of the recess 242.

All of the foregoing steps and operations are carried out through the cooperative action of the several cams on the cam shaft 10 and the associated cam followers. One revolution of the cam shaft 10, carrying the several cams with it, is suflicient to carry out, in sequence, all of those steps and operations. In order to assure a reliable once-around or single revolution operation of the cam shaft 10, with proper indexing at the end of each revolution, there is provided a novel single revolution type clutch. This clutch is shown in Figs. 19, 20 and 21, and is also disclosed in my copending application, Ser. No. 525,534, filed August 1, 1955, for Apparatus for the Sensing and Registration of Sheets.

A flywheel 278 is coupled to a suitable motor (not 9 shown). A clutch drum 280 is secured to the face of the flywheel 278 by suitable bolts 282. The cam shaft 10 extends through the rear panel 6 and into coaxial alignment with the clutch drum 280. The end of the shaft 10 carries a clutch yoke 284. Pivotally secured to the yoke 284 at one end is a pair of clutch shoes 286 with suitable linings 288 thereon. The other end of each of the shoe members 286 is coupled to the opposite end of the yoke 284 by an eccentric toggle arrangement which includes a pair of'toggle links 290 eccentrically mounted on a toggle key 292. The toggle key 292 is pivotally mounted on the yoke 284. The toggle ends of the two shoe members286 are normally biased apart by a main clutch spring 294. The spring 294 surrounds a guide pin 296 which extends through end portions on theshoe members 286. A pair of studs 298 extend out from the face of the yoke 284 and are positioned to limit the rotational movement of the toggle key 292 by engagement with an arm 300 which extends from the hub of the toggle key. A spring 302 is coupled to the arm 300 of the toggle key 292 and biases that key in a I direction to augment the separating force applied to the shoes 286 by the spring 294.

The end of the yoke 284 adjacent to the toggle constitutes a cam surface 304 which engages an indexing roller 306 carried by a spring biased arm 308 positioned adjacent to the clutch. A clutch pin 310 extends through the rear panel 6 (see Figs. 4 and 21) and engages the arm 300 of the toggle key 292. The pin 310 is retractable from engagement with the arm 300 by operation of a lever 312 which is biased by a spring 314 and actuated by a solenoid motor 316.

In the idle condition, as shown in Fig. 19, the flywheel 278, with the clutch drum 280, is continuously rotated by the driving motor. The clutch shoes 286 are held out of engagement with the drum 280 by operation of the toggle arrangement. The arm 300 on the toggle key 292 is held in position to cause disengagement of the shoes 286 by the clutch pin 310. With the clutch pin extended, as in Fig. 19, the arm 300 of the toggle key is held securely between the clutch pin 310 and the lowermost of the studs 298. The clutch yoke 284 is prevented from moving in a reverse direction by the indexing roller 306 which engages the yoke 284 adjacent the'cam' surface 304.

When the solenoid motor 316 is energized by operation of a suitable switch (not shown), the lever 312 is operated to retract the clutch pin 310. When the pm 310 is retracted, the arm 300 of the toggle key 292 is pulled by the spring 302 to shift the toggle bolts 290 and thus allow the spring 294 to move the shoes 286 into driving engagement with the drum 280. The upward movement of the arm 300, as viewed in Fig. 19, is limited by the uppermost one of the studs 298. When the shoes 286 are moved into engagement with the drum 280, the yoke 284 is rotated, carrying the shaft 10 with it. By the time the yoke 284 nears the completion of one revolution, the pin 310 will have been returned to its normal or rest position. The arm 300 of the toggle key 292 thereupon comes into contact with the side of the pin 310. The inertia of the clutch carries the mechanism with at least enough force to cause the coaction of the arm 300 and the pin 310 to overcome the force of the spring 302 and the spring 294 to disengage the shoes 286 from the drum 280. At about the same time that the arm 300 comes into contact with the pin 310, the roller 306 engages the cam surface 304 of the yoke 284. As the roller 306 moves outward on the cam surface, the spring bias on the roller arm 308 adds a further decelerating force to the yoke 284. The position of the roller 306 is made adjustable so that it drops over the edge of the cam surface 304 at the instant that the arm 300 is locked between the pin 310 and the stud 298. This arrangement positively locks and indexes the yoke 284 and, hence, the cam shaft 10 a 0 in rest position, ready to start another cycle whenever the pin 310 is retracted.

There has thus been provided an improved apparatus for forming and applying wire staples to the edge of a sheet member,the apparatus being characterized in that no strains are imparted to the sheet member during the application, and being further characterized in an improved drive means for such apparatus which includes a selectively engageable and automatically disengageable clutch mechanism.

I claim:

1. A wire staple fastener apparatus, comprising means for forming from wire a reversely-bent staple having a loop portion and a pair of legs, means for holding said loop portion and bending the ends of said legs to a plane angularly related to said loop portion, means for confining said legs to maintain them relatively rigid and for driving said ends through a sheet member in proximity to an edge of said sheet member while said legs are so confined, means for thereafter'bending said leg ends back toward said loop portion along straight paths snugly up against said sheet member-and beyond said sheet member edge, and means for thereafter bending said leg ends -over said sheet member edge and over said legs and for clinching said ends onto the surface of said sheet member.

2. A wire staple fastener apparatus comprising means for forming from wire a reversely-bent staple having a loop portion and a pair of legs, means for holding said loop portion and bending the ends of said legs to a plane at right angles to the plane of said loop portion, means for embracing and supporting said legs and for driving said ends through a sheet member in proximity to an edge thereof, further means for holding said loop portion and bending said leg ends back parallel to said loopportion, and means for thereafter bending said leg ends over said sheet member edge and over said legs and for clinching said ends onto the surface of said sheet memher while said loop portion remains held by said last mentioned holding means.

3. A wire staple fastener apparatus comprising means for forming from wire a substantially U-shaped staple having a loop portion and a pair of legs, means for holding said loop portion and bending the ends of said legs to a plane perpendicular to the plane of said loop portion, means for embracing and supporting said bent ends of said legs and for driving said ends through a sheet member in proximity to an edge thereof, further means for holding said loop portion during subsequent bending operations, means for bending said leg ends back parallel to said loop portion, means for thereafter bending said ends over said sheet member edge and past said legs, and means for bending said ends over said legs and clinching said ends onto the surface of said sheet member.

4. A wire staple fastener apparatus comprising means for forming from wire a substantially U-shaped staple having a loop portion and a pair of legs, means for holding said loop portion and bending the ends of said legs to a plane perpendicular to the plane of said loop portion, means for embracing and supporting said bent ends of said legs and for driving said ends through a sheet member in proximity to an edge thereof, further means for holding said loop portion during subsequent bending operations, means for bending said leg ends back parallel to said loop portion, means for there-after bending said ends over said sheet member edge and past said legs, means for bending said ends over said legs and clinching said ends onto the surface of said sheet member, and means for ejecting said staple from said last mentioned holding means.

5. A wire staple fastener apparatus comprising a staple forming assembly for forming from wire a reversely bent staple having "a loop portion and a pair of legs; a leg bending assembly including means for holding said loop portion, means for bending the ends of said legs to a plane angularly related to the plane of said loop portion, and means for driving said bent ends of said legs through a sheet member 'in proximity to an edge thereof, said driving means including means for embracing and supporting said leg ends during said driving; and a leg end clinching assembly including further means for holding said loop portion, means for bending said ends back toward said loop portion, means for further bending said ends over said sheet member edge, and means for still further bending said ends over said legs and clinching said ends onto the surface of said sheet member.

6. The invention as set forth inclaim characterized by the addition of ejection means for ejecting said loop from said last mentioned holding means.

7. A wire staple fastener apparatus comprising a staple forming assembly including a contoured anvil member and a complementary slide member for forming from wire a substantially U-shaped staple having a loop portion and a pair of legs; a leg bending assembly including means for holding said loop portion, means for bending the ends of said legs to a plane perpendicular to the plane of said loop portion, and means for driving said bent ends through a sheet member,'said driving means including means for embracing and supporting said ends during said driving; a leg end clinching assembly including further means for holding said loop portion, means for bending said ends back parallel to said loop portion, means for further bending said ends over the edge of said sheet member and clinching said ends over said legs and onto the surface of said sheet member; and common driving means for all of said assemblies.

8. A wire staple fastener apparatus comprising a staple forming assembly including a contoured anvil and a com plementary slide member for forming from wire a substantially U-shaped staple having 'a loop portion and a pair of legs; a Wire feeding mechanism for feeding to said staple forming assembly and severing a measured length of said wire; a leg bending assembly including means for holding said loop portion, means for bending the ends of said legs to a plane perpendicular to the plane of said loop portion, and means for driving said ends through a sheet member in proximity to an edge thereof, said driving means including means for embracing and supporting said ends during said driving; a leg end clinching assembly including further means for holding said loop portion, means for bending said ends back parallel to said loop portion, means for further bending said ends over said sheet member edge and clinching said ends over said legs and onto the surface of said sheet member; and common driving means for all of said assemblies.

9. A wire staple fastener apparatus comprising a retractable staple forming anvil contoured to the shape of the staple, a complementary slide member, means for feeding and severing a measured length of wire between said anvil and said slide member, means for driving said slide member into engagement with said anvil to form said wire into a substantially U-shaped staple having a loop portion and a pair of legs, means for retracting said anvil from the path of said slide member, means for bending said legs of said staple to a plane perpendicular to the plane of said loop portion, means for continuing the motion of said slide member after formation of said staple to move said staple to said leg bending means, said leg bending means including a staple holding block for supporting said loop portion of said staple, a pair of separable jaw members which embrace the end of said block and a portion of said loop portion, and a leg bending slide plate operable tobend the ends of said legs over said jaw members and then to separate said jaw members, said holding block being operable to drive said ends of said legs through a sheet member in proximity to an edge thereof, said slide plate having a pair of recesses for receiving and supporting said bent ends of said legs during said driving, additional means including said block for holding said loop portion of said staple subsequent to the driving of said leg ends through said sheet member, a first pair of leg-bending arms operable to bend said leg ends back parallel to said loop portion, a second pair of leg-bending arms operable to bend said leg ends over said sheet member edge, and a pair of clincher arms operable to bend said ends over said legs and clinch said ends onto the surface of said sheet member.

References Cited in the file of this patent UNITED STATES PATENTS 1,119,510 Heim Dec. 1, 1914 1,167,764 Liebig Jan. 11, 1916 1,264,901 Craig May 7, 1918 1,811,028 Ryan June 23, 1931 1,825,140 Berthold Sept. 29, 1931 2,138,495 Lewis Nov. 29, 1938 2,216,453 Paulin Oct. 1, 1940 2,566,031 Nilson Aug. 28, 1951