US3638687A

US3638687A - Wire-forming machine

Info

Publication number: US3638687A
Application number: US52338A
Authority: US
Inventors: Gerald B Bardo
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1970-07-06
Filing date: 1970-07-06
Publication date: 1972-02-01
Anticipated expiration: 1989-02-01

Abstract

A wire-working machine in which the free end of a strand of wire is forced through a tunnel in a bending die to form a loop. The end of the strand of wire is held rigid by a brake mechanism and a movable wire guide. A drive mechanism moves the bending die forward causing the wire guide to be displaced longitudinally along the wire, thus forcing the end of the wire through the tunnel. A clamp and cut bar operated by a variable stroke toggle mechanism clamps the leading end of the wire as it emerges from the die tunnel. The bending die is driven in reverse from the die tunnel. The bending die is driven in reverse direction to draw wire from a supply through the wire guide which moves with the bending die a portion of the return distance. The clamp and cut bar is again operated by the variable stroke toggle to sever the loop from the strand and to unclamp the severed loop to permit removal by an article carrier to a subsequent work station.

Description

United States Patent Bardo 1 Feb. 1, 1972 [54] WIRE-FORMING MACHINE Primary Examiner-L0wellA, Larson [72] Inventor: Gerald Bard), Nichos Attarneyl-lanifin and Jancin and John S. Gasper [73] Assignee: International Business Machines Corpora- [57] ABSTRACT Armonk NY A wire-working machine in which the free end of a strand of [22] Filed: July 1970 wire is forced through a tunnel in a bending die to form a loop. The end of the strand of wire is held rigid by a brake Appl' 52338 mechanism and a movable wire guide. A drive mechanism moves the bending die forward causing the wire guide to be [52] US. Cl ..140/71, 140/102 i pl gi in lly l g the i thus f r ing the n f [51] B21f 1/00 the wire through the tunnel. A clamp and cut bar operated by 58 Field of Search 140/1, 71, 102; 72/294, 312 a variable Stroke toggle mechanism clamps the leading end of the wire as it emerges from the die tunnel. The bending die is 56] References Ci driven in reverse from the die tunnel. The bending die is driven in reverse direction to draw wire from a supply through UNITED STATES PATENTS the wire guide which moves with the bending die a portion of the return distance. The clamp and cut bar is again operated 3,079,957 3/1963 Weiss ..140/7l 3,215,168 11/1965 Dian et al. ..140/71 by the vanable toggle Sever the from and to unclamp the severed loop to permit removal by an article carrier to a subsequent work station.

24 Claims, 17 Drawing Figures PATENIEU FEB lmz 3,638,687

sum 1 OF 8 PATENTEU FEB 1 I972 SHEET 3 OF 8 PRC-3.3

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FIG.4

PATENYEU FEB H972 3538587 SHEET 7 0F 8 AIR SUPPLY PATENTED FEB 1 I972 uNcLANP-cuL,

SHEET 8 OF 8 WIRE LOAD ER SEQUENCE CHART CUT/ CLAMP CLAMP OPEN COVER CLOSE CLAMP ANTI BACK RELEASE RAISE RAISE LOWER LOWER FOREWARD LEADSCREW DRIVE RETRACT EXTERNAL HOLDER CLAMPS WIRE CLAMP OPENS WITHOUT CUTTING WIRE FEEDING AROUND TUNNEL FEED WIRE LOOP TO DESIRED SIZE FIG. 17

WIRE-FORMING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to wire working machines and particularly to a wire forming machine which makes U-shaped loops of wire from a continuous strand.

2. Description of the Prior Art Wire-working machines are well known in which a small loop is first formed in the leading end of a flexible strand of wire. The loop is then enlarged to the desired size and then severed from the strand. In one form of such a prior art machine, the leading end of the strand of wire is wrapped around a cylindrical mandrel. The leading end of the wire is clamped and held stationary while the mandrel is moved to draw the strand of wire from its reel to the desired size. A cutting tool severs the formed loop from the strand and the loop is released and removed from the machine. To repeat the process. the mandrel and wrapping tools are returned to their initial positions, and the wire feed mechanism operated to provide a portion ofwire for again bending around the mandrel.

In present day high production environment, greater machine efficiency is required and greater precision in forming and sizing the loops for use in miniaturized high-density electronic packaging is a necessity. In addition, a suitable wire working machine is one which is relatively simple and which is readily adapted to automated operation under control of electronic data processing equipment, or the like, using digital techniques.

SUMMARY OF THE INVENTION Therefore, it is a broad object of the present invention to provide a wireworking machine which will meet the above requirements.

It is a more specific object to provide an improved wireworking machine for producing U-shaped wire loops which is greatly simplified, more efficient, capable of precision loop forming, and which is adapted for automated operation by electronic data processing devices, or the like, digital control devices.

The above, as well as other objects, are attained in accordance with the present invention by providing a wire holder means which supports the end of a flexible strand of wire in columnar fashion and a die member having a curved passageway for blending the leading end of the wire. In accordance with this invention, the die member is reciprocated relative to the wire holder to force the end of the wire through the passageway and then to pull the wire from the wire strand through the wire-holding means. The wire-holding mechanism comprises a wire brake which prevents reverse movement of the wire and a movable wire guide which coacts to hold the wire rigid and in alignment with the passageway. The wire guide is adapted to be displaced along the wire (while maintaining it rigid and in alignment with the passageway) by the bending die such that movement of the bending die forces the end of the wire through the tunnel to bend the wire while the brake holds the wire firmly against bending and movement. A clamp member carried by the movable wire guide grips the end of the wire as it emerges from the tunnel. The clamp is preferably a bar element which further includes a cutter and a straightener. The clamp and cut bar is reciprocably movable on the wire holder by a mechanical linkage whose stroke is controllably varied as a function of the position of the wire holder. Thus, by forcing the end of the wire through a bending die and then drawing the wire from the supply, a wire-feeding mechanism is eliminated. Using a movable wire guide with a clamp and cut bar attached thereto further simplifies the mechanism and makes precision sizing of loops readily obtainable.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an embodiment of the wire-working machine of the present invention;

FIG. 2 is a side elevation of the machine of FIG. 1;

FIG. 3 is an elevation view taken along line 3-3 of FIG. 2 with parts shown in section;

FIG. 4 is an elevation view taken along line 44 of FIG. 2 showing the die member assembly;

FIGS. 5 & 6 are an enlarged fragment from FIGS. 1 and 2 showing the die assembly;

FIG. 7 is an enlarged plan view of the wire brake shown in FIG. 2;

FIG. 8 is an end view of a wire brake mechanism of FIG. 7',

FIGS. 9-13 are a sequence of drawings schematically illustrating the principle operation of the machine described in FIGS. 14;

FIGS. 14 and 15 are plan views of a schematic showing of the cut and clamp bar and operating mechanism;

FIG. 16 is a schematic of a pneumatic system for operating the machine of FIGS. 14 according to the sequence shown in FIGS. 5-11; and

FIG. 17 is a timing chart illustrating the timing of the sequence of operations of the machine of FIGS. 14.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIGS. 1 & 2, a die assembly 20 is reciprocatable horizontally by a drive mechanism which comprises drive motor 21, gear train 22, and lead screw 23. The die assembly and associated drive mechanism are mounted in any known manner to a frame 24, pivotally connected at one end to standards 25 & 26 which extend upwardly from baseplate 27. An elevating mechanism for frame 24 comprises a pneumatic cylinder 28 attached at one end by clamp 29 to base 27 with the piston rod 30 connected to arm extension 31 of frame 24. Rails 32 & 33 of frame 24 guide the die assembly 20 as it is moved reciprocably by rotation of lead screw 23, due to rotation of motor 21 and gear train 22. The motor 21 is preferably an electric motor operable by control means (not shown) connected through an interface to an electronic data processing system, if desired. The gear train 22 and lead screw 23 may be of any well-known type and would be selected to provide rotational speeds and torques dependent on the size, flexibility or other parameters of the wire.

The die assembly 20, as best seen in FIGS. 4,5, and 6 comprises a gear block 34 with threaded aperture for drivingly engaging lead screw 23. A block extension 35, or the like, slidably moves along rails 32 & 33 to prevent rotational movement of die block 34 as lead screw 33 is rotated. Attached to block 34 is a wire bending die comprising a vertical die block 36 and a die cover plate 37. The top surface of die block 36 is machined to provide a vertical semicylindrical post 38. The front edge of die plate 37 has a semicircular cutout 39 and an extension or nose 40. A groove 41 is formed on the underside of the front edge of the plate 37 along the border of the cutout 39 and nose 40. Cover plate 37 is movable relative to die block 36 such that when cover plate 37 is moved to its most forward position, the lead edge of cutout 39 contacts the curved surface of post 38 to form a tunnellike wire bending passageway for bending wire. When die plate 37 is in its most forward position, nose 40 extends beyond'post 38 for the purpose to be later described.

To provide the relative motion of the die elements, a ball slide mechanism is provided comprising a stationary block 42 attached to gear block 34 and carrier member 43 which moves on ball bearings 44, or the like. Cover plate 37 is attached to the upper surface of carrier member 43 which is controllably moved by rod 45 of pneumatic cylinder 46 attached to bracket 47. The other end of pneumatic cylinder 46 is attached to gear block 34 through bracket 48.

Means for detecting whether the die plate 37 is in open or closed position comprises a sense switch 49 mounted on bracket 50 attached to gear block 34. A cam 51 attached to carrier member 43 of the ball slide mechanism so as to be movable with cover plate 37 activates the sense switch 49 through cam follower 52.

The wire-holding means of the present invention comprises a wire brake assembly 60 and a movable wire guide assembly 61, both mounted on a flat table plate 62 attached to the frame 24 in any well-known manner. As best seen in FIGS. 1, 2, 7, and 8, the wire brake 60 comprises a guide block 63 with a V-notch groove 64 in the surface thereof. The guide block 63, with groove 64 facing up, is attached to the upper surface of plate 62 so that groove 64 is in line with a strand of wire 54 coming from a bulk wire supply, such as wire reel 55, which may be mounted in convenient manner to the standards 24 & 26, or the like. During bending operation, wire 54 is held fixed in groove 64 by brake arm 65 pivotally mounted on block 63 by pin 66. A friction pad 67, or the like, which is preferably slightly deformable, is attached to the gripping end of arm 65 for pressing the wire 54 in groove 64. An operator for the gripper arm 65 to selectively hold or release the wire 54 comprises a pneumatic cylinder 68 having a plunger 69 movable outwardly and inwardly to rock arm 65 on pivot pin 66. Leaf spring 70 is fixed to the surface of block 60 for frictionally engaging wire 54 in groove 64 near brake arm 65. Leaf spring 70 provides sufficient frictional drag on wire 54 in groove 64 to assure that wire 54 is relatively taut as it is being pulled from reel 55 around post 38 of die block 36.

The movable wire guide assembly 61 of the wire holding means comprises guide plate 71 and guide block 72 attached to the movable guide carrier 73 of a ball slide mechanism in which the base block 74 thereof is attached to table plate 62. The ball slide mechanism is mounted on plate 62 so that guide carrier 73 moves horizontally along the length of wire 54 over ball bearings 75, or the like. Attached to guide plate 71 and extending outwardly therefrom is nose plate 76. A step 77 in the upper surface of nose plate 76 provides a two-sided bearing surface for wire 54 as it extends forwardly from brake mechanism 60. The nose plate 76 is formed and located on guide plate 71 so that step 77 is in alignment with the groove 41 of the cover plate 37. The step 77 in nose plate 76 is so located that when die assembly is advanced toward the wire guide means 61, the nose 40 of die plate 37 extends over the nose plate 76 to provide an extension of the passageway of the die assembly 20v This assures that the leading end of the wire is not deflected or bent when the die assembly 20 moves the wire guide assembly 61 along the wire 54 to force it into the groove 41 to be bent. Further guidance for wire 54 is provided by eyelet 78 formed in guide extension 79 of a bracket 80 whose base is attached to guide plate 71. Eyelet 78 is in line with step 77 of nose plate 76 so that eyelet 78 and step 77 are in contact with wire 54 at all times during longitudinal motion of carrier 73 along wire 54.

As previously mentioned, means is provided for clamping, cutting and straightening the wire in coordination with the movement of the die assembly 60 and the wire guide assembly 61. In accordance with this invention, these functions are preferably performed by a single device attached to the movable part of the wire-holding means. In the preferred embodiment, a bar 82 is slidably held on the upper surface of guide block 72 of carrier 73 by retaining plate 83. One end or bar 82 has an arm 84 slidably connected to link 85 of a toggle mechanism to be operated to reciprocate bar 82 relative to carrier 73 by means to be further described hereinafter. Attached to the other end of bar 82 is a cutter blade 86 having a cutting edge 87 adapted to sever wire 54 when bar 82 is reciprocated by toggle link 85. Intermediate the cutter blade 86 and arm 84 is clamp portion 88 extending parallel with surface 89 of nose plate 76 to grip the leading end of wire as it emerges from the groove 41 of the die assembly 20. Intermediate the clamp portion 88 and the cutting blade 87 is extension 90 which functions to straighten the end of the wire 54 after severing to bring it into alignment with bearing surfaces of step 77 of nose plate 76. Bar 82 is shaped so that blade 86 and extension 90 contact wire 54 along a transverse line between nose plate 76 and guide extension 79 of bracket 80.

The lateral spacing of the clamp portion 88, cutter blade 87 and straightener extension 90 along the length of bar 82 such that variable stroke reciprocation of bar 82 by linkage causes each to selectively perform their separate functions. Thus, a single bar and a single actuator mechanism is operable to perform clamping, cutting, and straightening operations thereby greatly simplifying the wireworking machine and increasing precision capability for forming loops in wire 54.

The mechanism designed for reciprocating the bar 82, as best seen in FIG. 14 & 15, comprises a toggle link 85 pivotally oscillated by piston rod 92 of pneumatic cylinder 93 attached to stationary plate 62 of the machine support frame. A spring 94 connected to bar 82 and to carrier 73 biases bar 82 so that clamp portion 88 bears against surface 89 of nose plate 76. When no wire is held by clamp portion 88, extension engages wire 54 as it extends from the eyelet 78 thereby correcting any bend in the end of the wire 54 and holding in alignment with the step surface 77 of nose plate 76. The clamping of wire 54 against surface 77 of nose plate 76, the cutting of wire by cutter 86, and straightening by extension 90 is performed by extending and retracting piston rod 92 by air supplied to cylinder 93. The stroke of piston rod 92 is fixed; however, the length of the stroke of bar 82 is selectively varied by movement of arm 84 of bar 82 to move pin 81 within opening 95 of toggle link 85 relative to its pivot point. Thus, when arm 84 of bar 82 is in the position shown in FIG. 14, (i.e., when die assembly 20 is advanced by drive motor 21 has fully displaced wire guide platform 73) the extension of piston rod 92 imparts a short stroke to bar 82 sufficient to separate clamp portion 88 from surface 89 of nose plate 76 to receive and clamp and free end of wire 54 as it emerges from groove 41 of die assembly 20. During this short stroke, cutter blade 86 does not move sufficiently to sever wire 54. On pulling of wire 54 from supply 55 when die assembly 20 has been driven by motor 21 to the left, as shown in FIG. 15, platform 73 will be at its extreme left position and arm 84 of bar 82 will be at its extreme left position and pin 81 will be located in opening 95 at the greatest distance from the pivot of toggle link 85. Thus, when piston rod 92 is extended, the stroke of bar 82 is great enough to cause blade 86 to sever wire along the line between nose plate 76 and guide extension 79 while simultaneously unclamping wire 54.

Thus, it is seen that clamping, cutting, and straightening is performed by a single mechanism operated by a single simplified mechanical operator. Only two positions of rod 92 are required, thereby greatly simplifying the automation of the operation.

For operating bar 82, as just described, a position sense switch 96 is provided (see FIG. 2) mounted on plate 62. A cam follower 97 for operating switch 96 rides on cam 98 attached to carrier 73 of the ball slide mechanism thereby sensing the motion of die assembly 20 and arm 84 as it moves to the rear position of FIG. 14. The location of switch 96 and cam 98 is such that cylinder valve 93 operates piston rod 92 to rotate toggle mechanism 85 to slide bar 82 to separate clamp 88 from surface 89 of nose plate 76 just as wire 54 emerges from tunnel of die member 20. Sense switches 99 & 101, with followers 100 8!. 102, respectively, are operated by movement of toggle link 85 when pivoted by piston rod 92. The forward limit of motion of the carrier 73 and, hence, bar 82 is controlled by motion rod 103 attached to plate 72. A spring 104 biases the ball slide mechanism forward. An adjustable stop nut 105 is provided on the threaded portion or rod 103 to abut stop member 106, thereby setting the forward limit position of platform 73. The rear limit position is controlled by limit switch 96.

FIG. 16 shows a schematic of an electropneumatic control system for operating the wire-working machine just described. An air supply is fed through a filter to a regulator 111 which supplies a substantially constant air pressure in parallel to control valves 112-115. Elevator control valve 112 is a four-way valve operated by an electromagnet 116 connected to an external controller which may be an electronic data controller such as a computer. Dual outputs from valve 112 are connected through parallel flow control valves 117 & 118 to opposite sides of piston of elevator cylinder 28 whose rod 30, as shown in FIG. 1, is connected to bracket arm 31 for raising and lowering platform 24. Limit arm 119 on rod 30 operates up and down limit switches 120 & 121 which are externally connected to control circuits which regulate operation of elevator electromagnet 116.

Control valve 113 is a three-way valve operated by control electromagnet 122 for selectively supplying air pressure through flow control valve 123 to brake release cylinder 68. Control valve 113 is normally open so that piston 124 is advanced upwardly from position shown, thereby operating brake arm 65 to grip wire in groove 64 of block 63. In the position shown, piston 124 is in brake release position due to energization of electromagnet 122. A limit arm 125 operates limit switch 126 to indicate to external control when brake is in release position.

Control valve 114 is a three-way normally open valve operated by electromagnet 127 to supply air through flow control valve 128 to piston 129 in cover operator cylinder 46. Rod 45 is connected to cover plate 37 of die assembly 20, motion of which operates sense switch 49. In the valve position shown, cover 37 is closed and a signal from external control to electromagnet 127 in response to predetermined motion of drive motor 21 moving die assembly 20 away from wire guide assembly 61 closes valve 114 retracting piston 129 to open cover 37.

Control valve 315 is a three-way, normally closed, valved operated by electromagnet 130 on signal from external control for supplying air selectively through flow control valve 131 to control cylinder 93 for operating toggle link 85 to move clamp-cut bar 82, as previously discussed. Sense switches 99 & 101, operated by toggle link 85, are electrically connected to external control to indicate operational condition of link 85.

While pneumatic control is shown in schematic form, persons skilled in the art could readily understand how to connect actual devices for supplying operational pressures, etc., as well as external controls for selectively synchronizing the pneumatic system with operation of the wire-working mechanism. In this regard, a sequence of operation of the various electrical and pneumatic devices is shown in FIG. 17.

The details of operation of the apparatus can be readily understood by reference to all the figures and particularly to FIGS. 9-17. As shown in FIG. 9, the die assembly 20 has been advanced by drive motor 21, gear train 22 and lead screw 23 to start line 135. AT this point, carrier 73 of the ball slide mechanism is biased forward by spring 104. The die block 36 (see FIGS. 5 & 6) has made contact with the front surface of nose plate 76, the wire guide nose 40 extends over step surface 77 of nose plate 76, and bar 82 is in clamp condition so that clamp portion 88 is in contact with surface 89 of nose plate 76. Also, the straightener extension 90 is in contact with the free end of wire 54 which now rests on the step surface 77 of nose plate 76. In this state of the apparatus, brake cylinder 68 has air supplied to it and brake arm 65 grips wire 54 in groove 64. The entire wire-working mechanism is held in lowered position by pneumatic cylinder 28.

FIG. shows the condition of the mechanism as lead screw 23 drives die assembly past start line 135. The ball slide carrier 72 has been displaced along wire 54 compressing spring 104 and the lead end of wire 54 has been forced into the groove 41 into the extended passageway formed by nose 40 and nose plate 76 and the passageway formed between die cover plate 37 and post 38 of die block 36. Bar 82 is still in clamp condition and frame 24 remains in lowered condition.

As lead screw 23 continues to move die assembly 20 past the start line 135, carrier 73, with nose plate 76 and eyelet guide 79, is moved further along wire 54 toward brake mechanism 63 which holds the wire 54 firmly driving the lead end of wire 54 further through groove 41 around post 38. At this stage, cam 98 wire guide carrier 73 operates limit switch 96 causing electromagnet 130 to switch control valve 115 to pressurize cylinder 93 to drive piston 92 overriding clamp bar spring 94 to rotate toggle link 85. Since carrier 73 has been driven back, pin 81 of arm 84 of bar 82 has been moved into groove 95, as previously described, close to the toggle link pivot so that a relatively short stroke is imparted to bar 82 separating clamp portion 88 from surface 89 of nose plate 76. Cutter blade 86 will not sever wire at this time. Lead screw 23 continues to drive wire 54 further through groove 41 around post 38 until it emerges from groove 41 to extend into the space between the separated clamp portion 88 and surface 89 of nose plate 76. Electromagnet 130 is operated by switching control valve 115 to exhaust air cylinder 93, releasing springs 132 & 94 to drive toggle link down causing bar 82 to move to clamp the emerged end of wire 54. As shown in FIG. 12, the die assembly 20 and carrier 73 will have been driven to its farthest position beyond start line 135 at which time the drive mechanism is reversed. Brake release valve 113 is switched by electromagnet 122 causing air to be exhausted from cylinder 68, thereby operating brake arm 65 to release wire 54 in groove 64. As shown in FIG. 17, frame 24 is still in-lowered condition.

With the brake release, the lead screw 23 is reversed by drive motor 21 and die assembly 20 is driven to the left, drawing wire 54 from supply reel 55 while spring 70 of brake mechanism 63 supplies drag to keep it taut. Initially, carrier 73, with nose plate 76 and eyelet arm 79, move under pressure supplied by spring 104 until start line 135 is reached where stop nut 105 engages stop 106 on plate 62 limiting further motion of wire guide carrier 73. Cam follower 97, riding on cam 98, carried by platform 73, operates sense switch 96 signifying the return of carrier 73 to the forward position and preparation for the next bending cycle. Lead screw 23 continues to drive die assembly 20 to the left of start line 135 a predetermined distance established by external control to draw a predetermined length of wire 54 from reel 55. When this length is reached, drive motor 21 is stopped. Wire clamp 133 from external apparatus is brought into position above the wire loop. As shown in FIG. 17, wire 54 is still clamped by bar 82, thereby keeping wire 54 under tension. Electromagnet 127 is energized switching control valve 114 to exhaust air from cylinder 46, thereby causing spring 135 to drive piston 129 to open cover 37. Electromagnet 116 is energized operating control valve 112 to supply air through flow control valve 117 and exhausting air through flow control valve 118, thereby raising platform 24. This causes the loop of wire 54 to be engaged by external gripper 133. Electromagnet is then energized causing piston 93 to oscillate toggle link 85. Since arm 84 of bar 82 has been moved so that pin 81 is at the greatest distance from the pivot of toggle link 85, bar 82 is moved a long stroke unclamping the leading end of wire 54 and moving the cutter blade 86 between nose plate 76 and guide arm 79 cutting wire 54. Electromagnet 116 is then activated to switch control valve 112, operating elevator cylinder 28 to lower frame 24, thereby freeing the wire loop from the die assembly 20 to be transported by clamp 133 to another work station. Electromagnet is then operated, causing cylinder 93 to rock toggle link 85 to move bar 82 to clamp condition. Since no wire is present at surface 89, clamp portion 88, under bias from spring 94, moves into engagement with surface 89 of nose plate 76. This allows bar 82 to move slightly further than when clamping wire. Thus, straightener extension 90 eliminates any bend formed in the severed end of wire 54 and restores its alignment with step 77 of nose plate 76 for alignment with groove 41. Thus, the wire-working mechanism is ready to repeat the cycle by again driving lead screw 23 to advance the die assembly 20 to start line 135 of FIG. 9. Thus, wire loop forming may be repeated any number of times and loop size is readily controlled precisely by adjusting length of motion of die assembly by controlling operation of drive motor 21. Not only does this permit repetitive forming of loops of the same size, but change of the size of the loop is readily made. Furthermore, since the supply of wire has already been drawn from reel 55 in the wire guide assembly 61, further feeding of wire prior to bending is eliminated and movement of die assembly 20, as described in PEG. 9, is all that is required to repeat the cycle. Thus, the wire loop forming is accomplished simply by reciprocating the die assembly 20 along with wire guide assembly 61.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

1 claim:

1. Apparatus for forming a loop of wire from a strand of flexible wire comprising:

means of holding the end of said wire in a substantially rigid columnar condition,

a bending die having a curved passageway,

means for effecting a first relative motion of said rigidly held wire and said bending die to force the leading end of said wire through said passageway to form a loop in the end of said wire;

means attached to said wire-holding means for gripping the free end of the bent wire as it emerges from said passageway;

means for effecting a second relative motion of said wireholding means and said gripping means and said die means to draw a predetermined length of the supply of said wire through said passageway; and

means for severing the drawn portion of said wire from said supply.

2. Apparatus in accordance with claim 1 in which said wireholding means is stationary and said die member is reciprocally movable in said first and second directions to effect said feeding and drawing of said wire through said passageway.

3. Apparatus in accordance with claim 1 in which said wireholding means comprises:

means for fixedly gripping said wire at some predetermined distance from the end of said wire;

means for slidably supporting said wire proximate the end thereof in alignment with the passageway of said die member; and

said slidable support means being displaceable along said wire by said die member during gripping by said wiregripping means to effect feeding of the free end of said wire through said passageway.

4. Apparatus in accordance with claim 3 in which said wiregripping means is a wire brake means selectively operated to grip said supply wire when wire is being forced through said passageway and to release said wire for drawing from a supply.

5. Apparatus in accordance with claim 3 in which said means for slidably supporting said wire comprises a carrier movable along said wire; and

wire guide means for aligning the end of said wire with said passageway fixedly attached to and movable with said carrier.

6. Apparatus in accordance with claim 5 in which said wireguide means comprises a nose plate attached to said carrier for slidably holding the free end of said wire in alignment with said passageway, said nose plate being fixedly attached to and movable with said carrier.

7. Apparatus in accordance with claim 5 in which said means for gripping the free end of said wire on emerging from the passageway of said die is movably attached to said carrier.

8. Apparatus in accordance with claim 5 which further comprises a bar movably supported on said carrier, said bar having clamp means for gripping the free end of said wire on emerging from said bending die, and cutting means for severing the drawn portion of said wire from said supply; and

operator means for moving said bar to sequentially grip and sever said wire in timed relation with the relative motions of said wire-holding means and said bending die.

9. Apparatus in accordance with claim 8 in which said out and clamp bar further includes means for straightening the end of said wire following cutting thereof to provide for alignment of the free end of said wire with said passageway by said nose plate.

10. Apparatus in accordance with claim 1 in which said bending die comprises first and second die elements having means for forming a tunnel for bending the free end of the wire forced therethrough.

1 1. Apparatus in accordance with claim 10 in which said die elements are relatively movable to open said tunnel to permit removal of a wire loop therefrom.

12. Apparatus in accordance with claim 11 in which said first die element comprises a die block having a semicylindrical or curved post for pulling wire from said supply upon the second relative motion of said bending die and said wire holding means; and

said second die element is a die coverplate having a semicircular cutout and groove coacting with said post for providing said bending tunnel for wire forced therethrough from said holding means.

13. Apparatus in accordance with claim 12 in which said die coverplate and die block are relatively movable to open said tunnel to permit removal of wire loops formed in said tunnel.

14. Apparatus in accordance with claim 12 in which said bending die further comprises a support block. a carrier movably mounted on said support block, and said die block is attached to said support block and said coverplate is attached to said carrier, and operator means attached to said support block and said coverplate for selectively moving said die coverplate and said platform for opening and closing said tunnel.

15. Apparatus in accordance with claim 14 which further comprises control means mounted on said support block of said bending die including means for sensing the motion of said coverplate.

16. Apparatus in accordance with claim 15 in which said sense means comprises a sense switch with cam follower attached to said support block and a cam operatively engaging said cam follower and attached to said coverplate.

17. Apparatus in accordance with claim 12 in which said coverplate has extension means adapted to engage said nose plate of said wire-holding means and to coact therewith to provide an extension of said passageway for guiding the free end of said wire into said bending tunnel.

18. Apparatus in accordance with claim 8 in which said bar further includes cutting means for severing the loop of wire from the strand.

19. Apparatus in accordance with claim 18 in which said bar further includes a straightener for engaging the end of said strand following severing of said wire to align the end of the strand with said passageway.

20. Apparatus in accordance with claim 8 which further comprises means for operating said bar for gripping the emerging free end of said wire; and

means for sensing the movement of said wire guide carrier for activating said bar-operating means.

21. Apparatus in accordance with claim 20 which further comprises means for sensing the wire drawing displacement of said bending die for operating said bar to disengage said gripping means of said bar from the free end of said wire and to advance the cutting means to sever the loop of wire from said strand.

22. Apparatus in accordance with claim 8 in which said operator means comprises a toggle mechanism having a movable operating connection with said clamp and cut bar.

23. Apparatus in accordance with claim 22 in which said toggle mechanism is a pivoted lever and said clamp and cut bar has arm means slidably connected to said pivoted lever for movement relative to the pivot of said lever.

24. Apparatus in accordance with claim 23 in which said operator means further comprises means for oscillating the pivoted lever; and

means for sensing the movement of said wire guide carrier of said bar relative to the pivot of said lever whereby said bar is reciprocated selectively different distances to sequentially grip and sever said wire.

Claims

1. Apparatus for forming a loop of wire from a strand of flexible wire comprising: means of holding the end of said wire in a substantially rigid columnar condition, a bending die having a curved passageway, means for effecting a first relative motion of said rigidly held wire and said bending die to force the leading end of said wire through said passageway to form a loop in the end of said wire; means attached to said wire-holding means for gripping the free end of the bent wire as it emerges from said passageway; means for effecting a second relative motion of said wireholding means and said gripping means and said die means to draw a predetermined length of the supply of said wire through said passageway; and means for seveRing the drawn portion of said wire from said supply.

2. Apparatus in accordance with claim 1 in which said wire-holding means is stationary and said die member is reciprocally movable in said first and second directions to effect said feeding and drawing of said wire through said passageway.

3. Apparatus in accordance with claim 1 in which said wire-holding means comprises: means for fixedly gripping said wire at some predetermined distance from the end of said wire; means for slidably supporting said wire proximate the end thereof in alignment with the passageway of said die member; and said slidable support means being displaceable along said wire by said die member during gripping by said wire-gripping means to effect feeding of the free end of said wire through said passageway.

4. Apparatus in accordance with claim 3 in which said wire-gripping means is a wire brake means selectively operated to grip said supply wire when wire is being forced through said passageway and to release said wire for drawing from a supply.

5. Apparatus in accordance with claim 3 in which said means for slidably supporting said wire comprises a carrier movable along said wire; and wire guide means for aligning the end of said wire with said passageway fixedly attached to and movable with said carrier.

6. Apparatus in accordance with claim 5 in which said wire-guide means comprises a nose plate attached to said carrier for slidably holding the free end of said wire in alignment with said passageway, said nose plate being fixedly attached to and movable with said carrier.

8. Apparatus in accordance with claim 5 which further comprises a bar movably supported on said carrier, said bar having clamp means for gripping the free end of said wire on emerging from said bending die, and cutting means for severing the drawn portion of said wire from said supply; and operator means for moving said bar to sequentially grip and sever said wire in timed relation with the relative motions of said wire-holding means and said bending die.

9. Apparatus in accordance with claim 8 in which said cut and clamp bar further includes means for straightening the end of said wire following cutting thereof to provide for alignment of the free end of said wire with said passageway by said nose plate.

11. Apparatus in accordance with claim 10 in which said die elements are relatively movable to open said tunnel to permit removal of a wire loop therefrom.

12. Apparatus in accordance with claim 11 in which said first die element comprises a die block having a semicylindrical or curved post for pulling wire from said supply upon the second relative motion of said bending die and said wire holding means; and said second die element is a die coverplate having a semicircular cutout and groove coacting with said post for providing said bending tunnel for wire forced therethrough from said holding means.

14. Apparatus in accordance with claim 12 in which said bending die further comprises a support block, a carrier movably mounted on said support block, and said die block is attached to said support block and said coverplate is attached to said carrier, and operator means attached to said support block and said coverplate for selectively moving said die coverplate and said platform for opening and closing said tunnel.

20. Apparatus in accordance with claim 8 which further comprises means for operating said bar for gripping the emerging free end of said wire; and means for sensing the movement of said wire guide carrier for activating said bar-operating means.

24. Apparatus in accordance with claim 23 in which said operator means further comprises means for oscillating the pivoted lever; and means for sensing the movement of said wire guide carrier of said bar relative to the pivot of said lever whereby said bar is reciprocated selectively different distances to sequentially grip and sever said wire.