US3504838A - Bottom stapler - Google Patents

Description

A. E. CAIRATTI April 7, 1970 BOTTOM STAPLER 5 Sheets-Sheet 1 Filed April 24, 1968 A. E. CAIRATTI April 7, 1970 BOTTOM STAPLER 5 Sheets-Sheet 2 Filed April 24, 1968 gawk May;

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A. E. CAIRATTI BOTTOM STAPLER April 7, 1970 5 Sheets-Sheet 5 Filed April 24, 1968 United States Patent 3,504,838 BOTTOM STAPLER Anthony E. Cairatti, Herrin, Ill., assignor to Werner Schafroth, Herrin, Ill. Filed Apr. 24, 1968, Ser. No. 723,702 Int. Cl. B27f 7/10, 7/16; B311) 1/68 US. Cl. 227-89 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates in general to stapling machines, and in particular, to a bottom stapler for stapling the bottoms of cartons, said bottom stapler having forming links mounted on a yoke assembly to form a cut wire into a staple as previously formed staple is being driven.

Stapling machines utilizing straight out wires to increase the magazine capacity are old in the art. In the past, such stapling machines utilized the driving blade or means movable with and attached to the driving blade to form a staple in a position rearwardly of the staple which is being driven.

One of the principal objects of the present invention is to provide forming links connected to yoke assembly of a bottom stapler. Another object is to provide for the formation of staples gradually by means of force applied adjacent to the ends of the cut wire instead of moving a die vertically downwardly and sliding the die against the legs formed on the staple. Another object is to permit a construction in which the staple may be overformed to compensate for the inherent springback of the metal or any bow in the cut wires, so that the staple legs are truly perpendicular to the staple crown. Another object is to provide in such a stapling machine a driving blade which does nothing except drive staples and which has no staple forming mechanism connected to said blade itself. Another object is to provide a construction in which the staple itself, as it is being formed, retracts the pushers slidably mounted on the forming block. Another object is to provide for the start of the formation of a staple before the driving blade contacts the staple to be driven, so as to lock the roll of cut wires against any rearward movement. The roll of cut wires is prevented from rearward movement by the formed staple which is ready to be driven, and thereafter, by a partially formed staple. This construction eliminates the necessity of a spring loaded member or roller which biases the strip of cut wires downwardly to prevent rearward movement of the roll or strip. Another object is to provide a construction in which any wear occurs on the staple itself, because the partially formed staple moves the pusher, which is hardened tool steel, rearwardly as the staple is being formed. In the past, a vertically movable hardened steel die moved the pusher rearwardly resulting in wear between said parts.

These and other objects and advantages will become apparent hereinafter.

The present invention is embodied in a bottom stapler using cut wires hinged together in roll form, the yoke having forming links thereon for bending the outer edges of cut wires around a forming block to form staple legs, said partially formed staple legs moving pushers rearwardly during the formation thereof, said staple legs adapted to be bent more than 90.

3,504,838 Patented Apr. 7, 1970 The invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed. In the accompanying drawings which form part of this specification and wherein like numerals and symbols refer to like parts wherever they occur:

FIG. 1 shows a bottom stapler embodying the present invention on a manually operated bottom stapler machine,

FIG. 2 shows said bottom stapler on a power actuated machine,

FIG. 3 is a top plan view of the stapling mechanism for cut wires embodying the present invention,

FIG. 4 is a cross-sectional view along the line 44 of FIG. 3,

FIG. 5 is a front elevational view thereof,

FIGS. 6, 7 and 8 are fragmentary views showing the forming links in their upper, intermediate, and lower positions,

FIGS. 9, l0 and 11 are side elevational fragmentary views showing the pusher as it is moved rearwardly by the forming links in FIGS. 6, 7 and 8, respectively,

FIG. 12 is an exploded perspective view of a forming block and forming links embodying the present invention.

FIG. 13 is a rear view of the magazine and rear shell,

FIG. 14 is an exploded perspective view of the stapling head and magazine, and

FIG. 15 is a fragmentary cross-sectional view taken along the line 1515 of FIG. 6.

Referring now to FIGS. 1 and 2, the bottom stapler machine M has a frame which is generally old and comprises the base members 1 and 2 with a forward upright 3 having an anvil 4 and a handle or spacer member 5 thereon, and a rigid rear upright 6. A bar 7 having a pedal 8 therein is pivotally connected to the base member 1 (FIG. 1) on the pin 9. An upright link 10 is pivotally connected to the bar 7 by the pin 11 and to an upper frame 12 by means of the linkage 13. The upper frame 12 is pivotally connected to the rear upright 6 by the pin 14. The frame 12 receives the stapling head 15 in the forward portion thereof. The rear upright 6 is provided with means 16 for receiving a roll 17 of cut wires W. In the past, the upper frame 12 held a stapling head which was supplied with rigid clips of formed staples having crowns and legs thereon, and the operator would depress the pedal 8 to cause the stapling head to come down and drive a staple into the bottom flaps of a carton, which had previously been placed over the anvil 4. The older bottom staplers were operated either by hand or with a power cylinder 18, such as shown in FIG. 2, with a piston rod 19 therein. This requires the proper lubricators 20, pressure regulators 21, and hose connections 22 leading to the foot pedal 8. Upon depressing the pedal 8, the power cylinder 18 would force a piston rod 19 upwardly to cause the stapling head 15 to come down and clinch a formed staple against the anvil 4. These machines shown in FIGS. 1 and 2 are so designed that the parts are returned to their inoperative position with the stapling head 15 raised after a staple had been driven.

The present invention is embodied in the stapling head 15 of a bottom stapler M and is adapted to hold rolls of 5000 cut wires instead of individual rigid clips of 50 formed staples each. The purpose of this is to avoid the down time of the machine for reloading and to permit continuous operation and the driving of large numbers of staples without reloading.

The stapling head 15 (FIGS. 3-5) has a guide or magazine 25 though which cut wires move forwardly from the roll 17. This stapling head 15, which includes the guide 25, may be substituted for similar parts on present existing bottom staplers which use rigid clips of formed staples. The stapling head 15 is connected to the guide 25 which comprises a bottom plate 26 having side walls 27 and inturned flanges 28, and an inner channel 29 having upstanding sides 30 with top edges 31 thereon which support the strip of cut wires W as they move forwardly beneath the flanges 28. A mounting bracket 32, which has bearings 23 and a spring 24 therein, is connected to the bottom rear of the guide 25 and is provided with suitable mounting means, such as bolts 33, so that the stapling head may replace older types of stapling heads on existing bases and frames. The guide also has inclined side plates 34 at its forward end.

The cut wires W are generally straight, but may be slightly bowed due to their method of manufacture so that their edges may be higher than their central portion which receives the tape T, which may be plastic or other suitable material. Each cut wire W has a crown or central portion 35 with two end portions 36 which form the legs 37 of a staple S. The edges 38 of each cut wire W are pointed and form the points of the staple S. Each staple S has a bend or curve 39 between the crown 36 and the legs 37. The cut wires W are hingedly connected together by tape T extending over a portion of their crowns 36.

The stapling head 15 comprises a front shell 40 and a rear shell 41 which slidably receive a work assembly 42, which comprises a yoke 43, two outer side members 44 connected between the frame 12 and the yoke 43, two upright spring guides 45 with helical return springs 46 therearound and two forming links 47 with a staple driving blade 48 mounted therebetween. The staple driving blade 48 slides vertically within a blade guide 48a. The guides 45 and springs 46 fit within wells or vertical openings 40a within the front shell 40. Cams 49 are mounted between the shells 40 and 41. Each cam 49 has a straight vertical surface 50 with an inwardly extending cam surface 51 near the bottom 52 thereof. Each forming link 47 is pivotally mounted on the yoke 43 on a pin 53 and has an inner edge 54 at its upper portion 55 and a curved lower forming portion 56 at its lower end adapted to contact the outer end portions 36 of the cut wire W to bend them downwardly to form the legs 37 of a staple S.

The stapling mechanism 15 is provided with a forming block 57 (FIG. 12), which is made from a number of stamped parts. The forming block 57 comprises a support block 58 of mild steel, an upper plate 59 with downturned side flanges 60, a forward forming plate 61 of hardened tool steel with sloping sides 62 forming staple leg receiving notches 63 therein below the upper corners 64, and two slidably mounted pushers 65 biased forwardly by springs 66 positioned within openings 67 in the pushers 65 and maintained therein by the downturned rear flange 68. A guide channel 69 is positioned above the upper plate 59. The pushers 65 are slidably mounted in the cut-out portions 70 of the support block 58 and are held in such position by means of the downwardly extending side flanges 60 on the upper plate 59. Each pusher 65 has a sloping forward or curved cam 71 which is contacted and moved rearwardly by a cut wire W as its end portion 36 is bent downwardly to form a staple leg 37. During this bending which exceeds 90, the staple legs 37 move the pushers 65 rearwardly the thickness of one staple against the pressure of the spring 66.

The pushers 65 each have a vertical front wall 72, which is normally flush with the front face 73 of the forming plate 61. The pushers 65 also have a sloping surface 74 which is normally positioned opposite to the sloping sides 62 on the forming plate 61, and a narrow vertical surface 75 which abuts against the rear of the forming plate 61. The forming plate 61 has bevel portions 76 to direct the staple legs 37 downwardly should the staple tend to pivot as it is being driven. The top edge of the forming plate 61 is flush with the top surface of the guide channel 69 on which the cut wires W slide forwardly. The sloping sides 62 slope inwardly about 10. The upper comers 64 have a radius of 0.031". The guide channel 69 and the upper plate 59 are connected to the support block 58 by suitable means, such as a pin 77 and a screw 78. The forming plate 61 is connected to the support block 58 by suitable means, such as pins 79 and a screw 80. The support block 58 is secured to the bottom plate 26 by suitable means, such as the screws 81.

The rear shell 41 is provided with a hold down bracket 82 connected thereto by a screw 83. The hold down bracket 82 is provided with a hold down plate 84 and a hold down spring 85 connected by a bolt 86. The cut wires W move forwardly on the guide channel 69 and beneath the hold down plate 84 until they are stopped by the blade guide 48a, at which time they are in a so-called position No. 2. over the forming plate 61. Once the cut wire W has been formed into a staple S, it is moved forwardly by the pushers 65 to a so-called position No. 1 directly beneath the staple driving blade 48.

In operation, and in order to drive a staple S, the pedal 8 is depressed, which raises the link 10 (FIG. 1) or the piston rod 19 (FIG. 2) which lowers the forward portion of the frame 12 and moves the stapling head 15 down toward the anvil 4. When the head 15 stops, the frame 12 and the side members 44 and yoke 43 continue their downward movement to drive the forming links 43 and driving blade 48 downwardly. As the forming links 47 are lowered, the lower forming portion 56 first contacts the end portions 36 of the cut Wires W and gradually bends them down over the upper corners 64 of the forming plate 61. This is not an instantaneous bending as in prior machines. As the forming links 47 move to their lowest position (FIG. 8), they force the legs 37 into the notches 63 formed by the sloping sides 62 in the forming plate 61. This bends the legs 37 more than and as the forming links 47 are moved upwardly, the spring-back of the metal causes the legs 37 to be perpendicular to the crown 35. As the driving blade 48 moves downwardly, the pushers 65 are moved rearwardly until they are behind the legs 37 of the staple which was formed in position No. 2. When the driving blade 48 is moved upwardly under the force of the springs 46, the pusher springs 66 move the pushers 65 forwardly to place the formed staple S in position No. 1 under the driving blade 48 ready to be driven.

FIGS. 6-8 are front views and FIGS. 9-11 are side views showing the forming links 47 in their upper, middle, and lower positions and the pushers 65 in their forward, middle, and rearward positions, respectively. Referring to FIG. 6, the forming links 47 are freely pivotally mounted on pins 53 in the yoke assembly 43. The forming links 47 extend downward into the openings 87 between the shells 40 and 41. Upon downward movement of the yoke 43 with respect to the front shell 40, the curved lower ends 56 of the forming links 47 contact the end portions 36 of the cut wire W whose central portion 35 is mounted on the forming plate 61. This downward movement causes the links 47 to contact and be guided by the cam surface 50 as said links 47 bend the outer ends 36 downwardly over the corners 64 of the forming plate 61 to form the staple legs 37, as shown in FIG. 7. As the downward movement of the yoke assembly 43 continues, the lower ends 56 of the forming links 47 are moved or cammed inwardly by the cam surface 51 to bend the staple legs 37 slightly more than 90 to compensate for the inherent spring-back in the metal of the staples and/ or the bow in the cut wire W. As the staple leg 37 is formed during the more than 90 bending, the staple leg 37 contacts the arcuate surface 71 on the pusher 65 to move the pusher 65 rearwardly against the action of the pusher spring 66. While this has been happening, the driving blade 48 has been driving a previously formed staple S downwardly from the front shell 40 through the carton bottom to be stapled and against the anvil 4 to clinch the staple legs, thereby stapling the bottom closure. The inward movement of the forming links 47 is limited by the inner edges 54 thereof contacting the blade guide.

The means 16 permits easy replacement of the roll 17 of cut wires W and permits the roll 17 to rotate gradually to feed cut wires W to the magazine or guide 25 as they are needed. When the roll 17 is empty, a new roll of about 5000 or more cut wires, as desired, can then be inserted and threaded forwardly on the top edges 31 of the sides 30 until the first cut wire abuts against the blade guide 48a. In this position, the roll or strip of cut wires can be moved rearwardly except for the pressure exerted by the hold down plate 84. To prevent rearward movement, the pedal 8 should be moved downwardly to cause the first cut wire W in position No. 2 to be formed into a staple. Since the roll 17 has tape T thereon to secure the cut wires W to one another, once the first cut wire has been formed into a staple, the roll 17 cannot be moved rearwardly.

The forming block 57 arrangement permits the ends of the cut wires W to be bent more than 90 (FIG. 8) so that the legs 37 are truly vertical when the forming links 47 are removed and the inherent spring-back in the metal moves the legs 37 several degrees toward their original position.

It will be seen that, unlike prior devices, the forming links 47 gradually, and not instantaneously move the staple legs 37 downwardly around the upper edge 64 of the forming plate 61. This results in easier operation, since in a typical commercial size only about one-half pound more pressure need be exerted as the staple is being formed. Previously, a definite resistance point was encountered because the staple was formed instantaneously by sliding movement of a downwardly moving die. This arrangement avoids the necessity of close tolerances between forming dies and the forming links and also permits the staple to be over-formed (i.e. over 90), thereby permitting the staple legs 37 to spring back to a 90 position due to the inherent spring-back of the material.

In prior bottom staplers, staples were often underformed because of this spring-back and difficult points were encountered in the actuation of the machine due to the instantaneous formation of the staple in position No. 2. This also created much friction.

The present device moves the forming links 47 against the outer ends 36 of the cut Wires and allows a staple to be formed by a rolling motion and over a period of time. There is no wear between the forming links 47 and the pushers 65 because the staples, which are mild steel, move the hardened steel pushers rearwardly. If the pedal 8 is moved initially downwardly, a staple is partially formed and this prevents the roll or strip of cut wires from moving rearwardly without the necessity of any hold-down bar or roller.

This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. In a stapling machine for forming and driving staples formed from a band of cut wires connected together in side by side relation, said stapling machine having a casing with a stapling mechanism therein, said stapling mechanism having a driving blade mounted on a yoke, the improvement which comprises providing a forming block of substantially rectangular shape extending rearwardly of said casing, said forming block having a staple leg receiving notch in the forward portion of each of its sides and a pusher slidably mounted on each side thereof, each of said pushers having a cam thereon, said pushers being normally urged forwardly by resilient means so that the front faces of said cams are positioned adjacent to the front face of said forming block, and providing forming links connected to said yoke and extending downwardly and adapted to c ontact the end portions of a cut wire to bend said end portions substantially perpendicularly to the crown portion over a portion of the forming block and beyond into said staple leg receiving notches in the side of the forming block, said cut wire ends moving said pushers rearwardly when said out wire ends are pivoted downwardly to form staple legs during the driving of a staple Which has previously been formed.

2. The improvement set forth in claim 1 wherein said forming links are mounted on said yoke on either side of said driving blade and rearwardly thereof the width of one cut wire.

3. The combination set forth in claim 1 wherein each of said forming links is pivotally mounted on a pin in said yoke.

4. The combination set forth in claim 1 wherein each of said forming links has a curved lower end which is received in a vertical opening in the casing, said opening having a cam surface therein for forcing said curved lower end inwardly after said curved lower end has contacted said out wire end and has begun to bend said out wire end over the forming block, said curved lower end sliding along the cut wire end to bend the same more than 90 and force said cut wire end into a staple leg receiving notch in said forming block.

5. The combination set forth in claim 1 wherein said forming links are flat and the bottom of each forming link comprises a curved portion in the form of a circle.

6. The combination set forth in claim 1 wherein the cut wire ends are partially bent downwardly by said forming links before said driving blade contacts a previously formed staple and begins to drive the same.

7. The combination set forth in claim 1 wherein said forming link has a projection on its inner edge adapted to contact means to limit the inward movement of the forming links toward one another, thereby limiting the degree to which the forming links can bend the cut wire ends more than 90 and into the staple leg receiving notches of the forming anvil.

8. The combination set forth in claim 1 wherein the staple leg receiving notches in the side of said formlng blocks are formed by a sloping side wall which slopes inwardly from the top of said forming block about 10 from a vertical line.

9. The combination set forth in claim 1 wherein said forming link is maintained in contact with a cam surface positioned oppositely to said cut-out portion in said forming block after said forming link has contacted said cut wire, said cam surface causing said forming link to move inwardly in a predetermined manner upon downward movement of said forming link.

References Cited UNITED STATES PATENTS 1,437,228 11/ 1922 Craig. 3,245,203 4/1966 Miller. 3,279,673 10/ 1966 Schafroth 227-85 FOREIGN PATENTS 661,536 4/1963 Canada.

WAYNE A. MORSE, IR., Primary Examiner US. Cl. X.R.

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