US2962720A - Anvil construction - Google Patents

Description

2 Sheets-Sheet 1 Filed Sept. 19, 1958 Dec. 6, 1960 w. c. QUEDNAU ANVIL CONSTRUCTION ZZ/aZZerC. Quednazb, k W Q?- ANVIL CONSTRUCTION Walter C. Quednau, Berkeley, illl., assignor to Acme Steel Company, Chicago, Ills, a corporation of Illinois Filed Sept. 19, 1958, Ser. No. 762,122

4 Claims. (Cl. 1-2) This invention relates to improvements in wire stapling machines of the kind that automatically drive and clinch staples formed in the machine from wire segments cut from a Continuous wire supply. More particularly, the present invention is directed to a highly improved anvil for use in machines of this type.

In automatic wire stapling machines of the kind just mentioned, wire is intermittently advanced into the machine to a position wherein the innermost end portion of the wire lies across or through a slot in an anvil used in the formation of the staples. When the wire has reached this position a cutter automatically severs the end portion of the wire from the wire supply and a staple forming device then comes into contact with the severed wire segment to bend the same over the anvil to form a staple, the opposite ends of the severed segment becoming the legs of the staple. A driving member thereupon moves toward the head of the staple, first displacing the anvil from its staple supporting position, and then contacting the newly formed staple to drive it through a work-piece.

I In automatic machine operation of the kind just stated a serious problem arises in gripping the relatively short segment of wire and retaining the same in proper position on the anvil during the brief period that elapses between the time when the segment is cut from the wire supply and the time when it is contacted and bent over the anvil by the staple forming member. In normal operation this time lapse may be only a fraction of a second, but the vibration of the machine and the operation of the cutter are such that the severed segment will often slip or move with respect to the anvil during this interval, causing an improperly shaped staple to be formed unless the segment is firmly retained in its proper position on the anvil.

Previously used means for retaining the segment in proper position on the anvil during this period have comprised spring-pressed fingers built either into the anvil itself or constructed and positioned externally of the anvil so as to grip the segment before it is severed and thereafter retain the segment until it is subsequently contacted by the staple forming or driving members.

Externally disposed springpressed fingers or plungers have not affected the strength of the anvils with which they have been employed, but in o'rder that a machine embodying an externally disposed finger or plunger may be used to manufacture and drive staples of different widths it has been necessary that the finger or plunger be mounted in such a way that it could be moved from one position to another when an anvil of a different width was employed. The external finger or plunger required positioning close to an anvil for narrow widths to insure contact with the short wire segment and another positioning for the manufacture of staples of wider width to prevent the wider anvil from interfering with the ex ternal plunger or finger-like wire gripping means. The need for repositioning the external wire gripping means requires the use of special parts and is consequently Patented Dec. 6, 1960 undesirable in standardized machines capable of forming and driving staples of a variety of widths. In addition, externally disposed spring-pressed wire gripping fingers or plungers are made as small as possible so as to interfere with the work-piece as little as possible. They are therefore necessarily relatively weak, and because they must be placed in the vicinity of the workpiece, they are subject to being broken and bent by the work-piece and otherwise rendered inoperative because of dirt or other foreign material present in the work region. There is also another disadvantage of the ordinary type externally disposed spring-pressed wire gripper; it grips by pressing against the upper surface of one end of each staple wire segment passed through the wire receiving groove of the anvil to cause the wire segment to be tilted slightly from its normal path through the groove and thereby frictionally held between the upper surface of the groove on one end and its lower surface on the other end. This manner of gripping has proven only satisfactory. it requires that the wire cutting members which sever the segment from the main length of wire be sharp, otherwise, with dull cutting members the severing more nearly resembles a pinching action which causes the severed segment to jump forward and be displaced as it is cut because it is not gripped tightly enough. This is a deleterious condition which requires more fre quent replacement of the cutting members than would ordinarily be expected.

Certain types of internally disposed spring-pressed wire grippers have been used with varying degrees of success.

There is a form of this type using a positively actuated plunger which is positively cleared of the path of the wire to allow for the presentation to the anvil of the wire segment, after which the plunger is released to let it grip the wire under the force of spring pressure. This type of plunger has had the disadvantage of being complex because its operation must be linked to and timed properly with the other operative parts of the stapling or stitching machine.

It is therefore the principal object of this invention to provide an improved anvil construction in a stitching machine of the type referred to, which obviates the difficulties and shortcomings mentioned for prior art devices.

In order to accomplish this object, it is a further object of the invention to provide an improved anvil construction wherein the gripper is of the internally spring biased type and not an integral part of the anvil portion over which the wire segment is bent into a U-shape, is one which is separated by the action of the wire itself camming against it during wire feed, is one which does not require an excessively strong spring so that even light guage wire will not buckle when fed into the anvil, but which can use a spring strong enough to prevent slippage of the wire segment during wire cutting to thereby prolong the useful life of the wire cutting parts, and which is extremely simple in design so that it can be manufactured inexpensively and assembled easily and quickly. I

In order to provide such an improved anvil, it is another object of this invention to provide a gripper in the form of a rod protruding at its outer end into the wire receiving slot of the anvil, the rod being connected at its inner end to an enlarged portion. against which a spring reacts to urge the gripper forward of the anvil, the enlarged portion being mounted relative to the rod and positioned in a recess in the anvil in such a manner that the gripper is urged angularly by the spring to urge its outer rod end into the path of the wire receiving slot where it frictionally grips a wire segment positioned therein, the rod portion being of circular cross-section to provide a curved cam surface against which the wire being fed can react to deflect the gripper and permit access of the wire into the wire receiving slot in the anvil.

These and other objects and advantages of the present invention will be apparent from the following description of certain preferred embodiments thereof, taken with the accompanying drawings wherein:

Fig. l is a perspective and exploded view of one form of the improved anvil;

Fig. 2 is an elevation of an automatic wire stitching machine of a kind in which the anvil of Fig. 1 may be employed;

Fig. 3 is a fragmentary elevational view, partly in crosssection, of the lower portion of the machine of Fig. 2, showing the relative position of the anvil and the staple forming means of the machine after the staple has been formed over the anvil but before driving the staple has begun;

Fig. 4 is a cross-section taken substantially along the line 44 in Fig. 2, showing a length of wire in the anvil before the forming operation has begun;

Fig. 5 is a fragmentary elevation of the rear side of the lower portion of the machine;

Fig. 6 is a top plan view of the anvil of Fig. 1;

Fig. 7 is a side view thereof;

Fig. 8 is a front view of the anvil;

Fig. 9 is a longitudinal cross-section taken substantially along line 99 in Fig. 5 showing the interior construction of the anvil;

Fig. 10 is a lateral cross-section taken substantially along line Ill-10 in Fig. 6.

The anvil of the present invention in its first embodiment, is shown in detail in the drawings in Fig. 1 and in Figs. 6 to 10. As there illustrated, the anvil comprises a generally cylindrical body 30, of mild steel or the like, having two parallel planar work surfaces 31 formed on its opposite sides adjacent its forward end which, for the sake of clarity in description, will be called its nose or working end. A transverse open slot 32, preferably of rectangular cross-section, is provided in this working end of the anvil body and extends from one work surface 31 to the other, the longitudinal axis of the slot being normal to both surfaces. From a level slightly above the slot 32, the upper portion of the working end of the anvil body extends upwardly and rearwardly in an inclined planar. surface 33. That portion of the end of the anvil body below the slot, on the other hand, is curved downwardly and rearwardly as at 34 and converges smoothly with the generally cylindrical main portion of the anvil body. The effect of this construction is to provide the front of the anvil body with a forwardly extending nose-like arrangement having the transverse slot 32 formed therein into which stapling wire may be fed endwise in the direction shown by the arrow 35 in Fig. 1. In order to make it easier to feed the wire into the slot, the upper wall of the slot at one end thereof may be beveled upwardly as at 32a (Fig. 8) in order to provide a larger mouth for the slot.

The wire stapling machine in which this particular form of the anvil may best be employed, and the manner in which the anvil performs in the machine, will be described presently. At this point in the description, however, it will suffice to state that after a length of wire 36a has been fed endwise into the slot 32 to substantially the position shown by the straight broken lines in Fig. 1, with a portion of the wire extending from the opposite ends of the slot 32, the wire is cut or severed from the Wire supply and a staple former is thereupon downwardly in straddling fashion alongside the working surfaces 31 to bend the protruding ends of the Wire downwardly to form a staple having legs 36b. During this operation, it will be seen that the portion 36c of the wire contained within the slot 32 becomes the crown or upper portion of the newly formed staple.

The anvil body 30 is hollow and, as will presently be explained, it forms a shell for contents that act forcibly to retain or grip the length of wire 36a in the slot 32 during the severing and bending operations just referred to.

The anvil body 30 is provided with a cylindrical bore 37 extending axially inwardly from the rear end 38 thereof to a point short of shoulders 39 that define the innermost vertical edges of the working surfaces 31 on the sides of the body. The inner end 40 of the bore is flat and intersects an open slot 41 cut into the front portion of the anvil body 30 below the level of the wire receiving slot 32. The slot is defined by two parallel walls 42 and 43. This slot 41 extends into the anvil body to a region beyond the inner end 40 of the bore 37 and terminates at an inner end 44. When positioned properly in the stitching machine, a pin 45 provided in the frame 49 of the machine acts as a stop to limit the inward travel of the anvil body 30. Positioned in the bore 37 is the wire gripper 46 which comprises an enlarged cylindrical inner end 46a of slightly smaller diameter than the bore 37. This inner end 46a is ordi: narily urged forward of the anvil body 30 by means; of a compression spring 46b which reacts between the inner end 46a and a cover plate 71 which is fastened to the frame member 49 by means of four screws 71a. A raised projection 71b is provided in the plate 71 to keep the spring 46b in alignment. The forward surface of the end 46a of the wire gripper 46 is secured slightly below center to a smaller diameter cylindrical rod 46c which protrudes forward through the slot 41 where its free end 46d terminates in the region of the wire receiving slot 32 of the anvil. This rod 46c is slightly curved concavely upward with the result that it normally urges the enlarged end 46a to be displaced angularly from the bottom surface 40 of the bore 37 in the region 72. This angular displacement provides a degree of angular movement of the entire wire gripper which is resisted by the force of the spring 46b, but which enables the rod end 46d to be urged by the force of the spring 46b into wire gripping position as shown in Fig. 9 against the. length of wire 36a.

The automatic wire stitching machine in which the anvil just described may best be used is illustrated in Figs. 2 to 5. Machines of this general type are well-known in the art and need not be described in great detail here; The machine comprises a pair of feed rollers 47 each of which is mounted on a shaft 48 rotatably carried on a. supporting plate or frame member 49. The rollers 47 are rotated in synchronism and in opposite directions by a gear 50, carried and driven by a drive shaft 50a (Fig. 4), and by a pinion 51 which meshes with a gear 52 carried upon the back of the right-hand roller 47 as seen in Fig. 2. This latter gear meshes with an identical gear 52 carried on the back of the other roller. The drive shaft 50a is operatively connected to a driving motor or other source of power, not shown.

Each roller 47 has a peripheral cam 53 formed thereon, with feeding of the staple wire 36 between the rollers 47 taking place when portions of the cams 53 are opposite each other. A detailed description of the operation of these rollers 47 and their earns 53 may be found in US. Patent No. 2,199,241. It will suffice here merely to state that the rollers act to advance the wire 36 intermittently, once upon each complete cycle of the machine. The wire 36 from the feed rollers 47 enters awire guide 54 having a passage therein for slidably re-' ceiving the wire and directing the same to a'wire cutting device indicated generally by the numeral 55. During its passage through the wire guide 54 the wire may pass under a wire check 56 of the kind described in detain in US. Patent No. 2,478,397.

The plate or frame member 49 has formed thereon a pair of upright spaced projections 57 and 58 which constitute a guideway for a vertical reciprocating sliding block 59 that has a pair of staple formers 60 and 61 formed on its lower end in spaced apart relation. Retention of the block 59 between the projections 57 and 58;

is accomplished by a cover plate 62 extending across and secured to the projections 57 and 58 by screws 63. The sliding block 59 is reciprocated by means including a cam member 65 mounted upon the inner end of the drive shaft 50a. A cam groove 65 in the cam is adapted to receive a roller 66 carried on the sliding block 59 adjacent its upper end. From Figs. 2 and 4 it will be understood that the block 59 completes a downward stroke and returns to its uppermost position once during each complete revolution of the cam 64.

Slidably supported between the staple formers 60 and 61, for reciprocating movement is a staple driver 67 that is pivotally connected adjacent its upper end to one end of a connecting link 68 (Fig. 4) which has its opposite end rotatab ly supported upon a stub shaft 69 fixed upon the forward face of the cam member 64 in a position offset with respect to the axis of the drive shaft 50a. It will thus be seen that the staple driver 67 is reciprocated upwardly and downwardly as the shaft 50a revolves. The arrangement of the parts is such that the feed rollers 47, the staple formers 60 and 61, and the staple driver 67 are operated in a timed relation, with each being moved through a complete cycle during one revolution of the shaft 50a.

The anvil described above is located in the machine between the plate projections 57 and 58, and below the staple driver 57, in a path that lies between the staple formers 60 and 61. The anvil is slidably supported in a round transverse opening 70 (Fig. 4) in the frame member 49.

The wire 36 from the wire guide 54 passes through a cutter tube 75 carried in the plate projections 58, the staple former 61 being provided with a longitudinal groove 77 for slidably receiving the extended innermost end 76 of the cutter tube. A cutting tool 78 is mounted on the lower end of the staple former 61 for reciprocal movement therewith in a path across the end 76 of the cutter tube 75, the Wire 36 being cut by the tool 78 as the tool passes across the wire opening in the cutter tube.

In the operation of the stitching machine just described the wire 36 is fed by the feed rollers 47 through the guide 54 and the cutter tube 75 into the transverse slot 32 in the anvil while the staple formers 60 and 51 and the staple driver 67 are in their uppermost positions as shown in Fig. 2. The cylindrical rod portion 460 is of sufficient diameter that no more than its upper one-half protrudes into the slot 32 when no wire is present. Since this upper one-half has a curved surface, it presents a camming surface against which the leading end of the wire can react in order to deflect the rod portion 46c downward and clear of the slot 32 and thereby permit passage of the wire into the slot 32. Upon completion of the feeding operation, the staple formers and the staple driver are moved downwardly by the cam 64. In the initial phase of this downward movement the block 59, and the staple formers 60 and 61 that are formed thereon, descends at a rate more rapid than that of the staple driver. As the staple formers 60 and 61 approach the length of wire 36a contained in the slot 32 of the anvil, the cutting tool 78 severs the wire as it passes the end 76 of the cutting tube 75. The cutting of the length of wire 36a in this operation, however, does not disturb or dislodge the wire from the slot 32 because it is firmly gripped or held therein by the outer end of the rod portion 460. The length of wire 36a is thus retained in its proper position on the anvil, and when the staple formers 60 and 61 contact the wire, the ends of the wire protruding from the slot 32 are bent downwardly along the working surfaces 31 on the sides of the forward end of the staple body, the protruding ends of the length of wire 36a becoming the legs 36b of a newly formed staple. The legs 36b of the formed staple are thereupon retained in slots 60a and 61a (Fig. 3) provided in the staple formers 60 and 61, respectively, while the staple driving member 67 drives the staple.

' As the staple driver approaches its driving position the lower edge thereof strikes the oblique surface 33 on the front of the anvil body 30, forcing the anvil body rearwardly in the opening 70 against the compression of the spring 46b. Inasmuch as the legs 36b of the newly formed staple are retained in the slots 60a and 61a in the staple formers 60 and 61, this rearward movement of the anvil body 30 withdraws the anvil from the staple, the force against the oblique surface 33 of the anvil being sufiicient to overcome the grip of the rod portion 46d pressing the formed staple against the anvil. The staple driver then contacts the crown 36c of the newly formed staple and drives it downwardly into a carton or other work piece.

A member 80 (Fig. 4) is pivoted at 81 to the staple formers 60 and 61 for pivotal movement therebetween, the members 80 being yieldably movable to a position between the staple formers by a spring-pressed member 82 movably carried on the cover plate 62. The pivoted member 80 provides a support to prevent the staple legs from bending inwardly toward each other during the staple driving operation. The member 80 is pivoted outwardly from between the staple formers by the driver 67 as it approaches its lowermost position during the downstroke.

Although only one specific embodiment of the invention has been shown and described, it should be apparent to those skilled in the art that various changes may be made in construction without departing from the true scope of the appended claims.

I claim:

1. In combination with a wire stitching machine having wire feeding means, means for cutting said Wire and a staple former, an anvil comprising, an anvil body adapted to coact with said staple former in the formation of staples, said body having a fixed open transverse slot in one end thereof for receiving a length of wire fed by said wire feeding means, a wire gripper within said body biased by a spring urging the wire gripper into wire gripping position against a length of wire fed into said open transverse slot by said feeding means, said wire gripper having a wire gripping portion which is curved in crosssection to provide a wedge shaped wire entry between the wire gripper portion and one wall of said open transverse slot on the wire inlet side to thereby enable the end of the wire fed endwise by said wire feeding means to cam said Wire gripper portion clear of the open transverse slot and allow passage of the Wire into the open transverse slot.

2. In combination with a wire stitching machine having wire feeding means, means for cutting said wire, a staple former, and an anvil comprising, an anvil body adapted to coact with said staple former in the formation of U-shaped staples, said body having a fixed dimension open transverse slot in the forward end thereof for receiving a length of wire fed by said wire feeding means, a wire gripper contained by said body and provided with a rigid rod having a free end and another end secured to a plunger positioned at the bottom of a bore provided in the rear end of said body, said plunger being angularly positioned relative to the bottom of said bore when the rod is gripping a length of wire, a spring reacting against the plunger and urging it into a position of smaller angular relation with said bottom to thereby urge said free end of said rod into a position intersecting said open transverse slot to block the passage of wire thereto.

3. In combination with a wire stitching machine having wire feeding means, means for cutting said wire, a staple former, and an anvil comprising, an anvil body adapted to coact with said staple former in the formation of U-shaped staples, said body having a fixed dimension open transverse slot in the forward end thereof for receiving a length of wire fed by said wire feeding means, a wire gripper contained by said body and provided with a rigid rod having a free end and another end'secured to a plunger positioned at the bottom of a bore provided in the rear: end of said body, said plunger being angularly positioned relative to the bottom of said bore when the rod is gripping a length of wire, a spring reacting against the plunger and urging it into a position of smaller angular relation with said bottom to thereby urge said free end of said rod into a position intersecting said open transverse slot to block the passage of wire thereto, the rod having a cam surface against which the leading end of wire fed by said wire feeding means can react to displace the Wire gripper against the pressure of said spring and permit the passage of the wire into the open transverse slot. I

4. In combination with a wire stitching machine having wire feeding means, means for cutting said wire, a staple former and an anvil comprising, an anvil body slidable in the frame of the stitching machine between a wire receiving position and a retracted position and adapted to coact with said staple former in the formation of U-shaped staples, said body having a fixed dimension open transverse slot in the forward end thereof for receiving a length of wire fed by said wire feeding means and a longitudinal bore in its rear end extending partially through the length of the body and another opening providing a passage between the slot and the bore, a wire gripper contained by said body and provided with a rigid at the bottom of the bore with the rod extending through said passage with its free end intersecting the open transverse slot in the wire feed path, the plunger being urged against the bottom of the bore by a compression spring which is mounted to react between the frame of the wire stitching machine and the plunger for urging the free end of the rod into wire gripping position, said spring also urging slidable movement of the anvil body along the frame into its wire receiving position, the curvature of the rod acting as a cam surface for causing the Wire gripper to be deflected angularly bodily from the Wire path to a wire gripping position when wire is fed endwise into the transverse slot, this deflection causing the plunger to be positioned at a different angle relative to the bottom wall of the bore.

References Cited in the file of this patent UNITED STATES PATENTS

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