US3420279A - Secondary wire-bending machine - Google Patents

Description

Jan. 7, 1969 J. TUIT SECONDARY WIRE-BENDING MACHINE Sheet of 7 Filed July 1966 INVENTOR.

' JOHN 771/7 Jan. 7, 1969 J. TUIT SECONDARY WIRE-BENDING MACHINE Sheet Filed July 1966 l/VVEIVTOR JOHN 7'U/7' kg 2.

Jan. 7, 1969 J. TUIT 7 3,420,279

SECONDARY W IRE- BENDING MACHINE Filed July 5. 1966 Sheet 4 of 7 INVENTOR. JOHN 7'U/T Jan. 7, 1969 J. TUIT 3,420,279

SECONDARY wms-aznnme MACHINE Filed July 5, 1966 Sheet 5 of '2 INVENTOR. JOHN 7'U/7' BY '&. ,.,A -r

Jan. 7, 1969 .1. TUIT SECONDARY WIRE-BENDING MACHINE Sheet Filed July 5, 1966 w lw Jan. 7, 1969 J. TUIT 3,420,279

SECONDARY WI RE BEND ING MACHINE Filed July 6, 1966 Sheet 7 of 7 INVENTOR JOHN 7'U/7 BY ra United States Patent 4 Claims AESTRACT 015 THE DISCLOSURE A wire-bending machine having rotatable jaws for hold ing and twisting wire workpieces, and also having bending arms adapted to bend workpieces held in the jaws around portions of the jaws at a selected rotary position of the jaws to conform the workpiece to a forming configuration on the side of the jaws.

This invention relates to the construction of machines designed to perform bending operations on a type of wire spring element commonly referred to as shaped wire. These elements are essentially serpentine pieces of steel wire, and are used in large numbers in the seats and backs of vehicle seat units. The configuration of these spring elements is usually an initially coplanar wave-like formation modified by secondary bending operations. The current method of anchoring the ends of these spring elements is by inserting a short bight of wire into a slot in a tubular beam with a force fit that utilizes the resilience of the wire. The shape of these end-bights must be carefully controlled to maintain the necessary fit and position of the spring elements, and it is in the formation of this part of the spring elements that the preferred form of the present invention has been applied.

In summary, the initially coplanar spring element is placed in position in the machine by an automatic device, after having previously been bent into the serpentine form. A jaw moves out and seizes a portion of the element at a point back somewhat from the end of the bight. A device advances from the opposite side of the machine, and wraps the exposed portion of the bight around the holding jaw, and then retracts. The holding jaw then rotates about the axis of a transverse section of the serpentine configuration, while the opposite side of the spring element is held against rotation, to swing the bight away from the original plane of the wire element. Further bends may be formed by other sections of the machine on the parts of the wire still in the planar configuration. The preferred form of the invention is constructed to perform operations such as those summarized above, while maintaining close bending tolerances and fully automatic operation.

The features of the invention will be analyzed in detail through a discussion of the particular embodiment illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a plan view of the portion of the machine embodying the subject invention, in the condition in which the wire workpiece is initially received.

FIGURE 2 illustrates the mechanism shown in FIG- URE 1 in the second principal position of the components, with the wire workpiece shown seized in preparation for the performance of the first bending operation.

FIGURE 3 is a plan view on an enlarged scale of the portion of the machine immediately adjacent the situs of the bending operations.

FIGURE 4 is a section on the plane 4-4 of FIG- URE 3.

FIGURE 5 is a view of the mechanism shown in FIG- 3,420,279 Patented Jan. 7, 1969 ice URE 3, after the completion of the first bending operation.

FIGURE 6 is a section of the plane 66 of FIG- URE 5.

FIGURE 7 is a view on the plane 77 of FIGURE 5, on a somewhat reduced scale.

FIGURE 8 is a view similar to FIGURE 6, showing the relaxed position of the bending member assumed after the completion of the bending operation shown in FIGURE 6, preparatory to retraction of the bending member.

FIGURE 9 is a plan view illustrating the second bending operation, in which the formed bight is rotated away from the initial serpentine plane, with the displacement taking place about the axis of a transverse portion of the wire element.

FIGURE 10 is a view on the plane 1010 of FIGURE 1, on an enlarged scale.

FIGURE 11 is a view on the plane 1111 of FIG- URE 9.

FIGURE 12 is a fragmentary view showing the power transfer system utilized to rotate the bending jaw.

FIGURES 13, 14 and 15 illustrate successive conditions in the wire workpiece as the bending operations proceed.

The machine shown generally in FIGURES 1 and 2 has a rigid frame which includes the mounting rails 20 and 21. An automatic placement device (not shown) positions the serpentine wire workpiece 22 at a particular location corresponding to the position of the rotatable jaw assembly 23 and the bending device 24. The placement of the wire workpiece 22 is such that the jaw assembly 23 grasps the bight 25 at a position somewhat back from the end of the bight, leaving a major portion of the bight exposed for the action of the bending arm 26. When the wire 22 is initially placed in the machine, the bending device 24 and the jaw assembly 23 are retracted as shown in FIGURE 1 to an extent permitting the wire workpiece to be placed downwardly into the position for engagement with the components of the machine.

The structural details of the jaw assembly appear best in FIGURES 3, 4, 9, and 10. The opposite jaws 27 and 28 are secured to the blocks 29 and 30 with a freedom of movement between the positions shown in FIGURES 9 and 10. The mechanism for inducing this change of position forms no part of the present invention, and is not shown in detail. The components including the jaws 27-28 and the blocks 2930 are mounted on the shaft 31, and this shaft is capable of both rotation and axial movement. Rotation is controlled by the interaction of the gear 32 and the rack 33, with the latter being moved vertically by the air cylinder 34. The gear 32 is slidably, but non-rotatably, mounted on the shaft 31, with this relationship being obtained either through the use of a square cross-section on the shaft, or by a suitable spline arrangement. In either case, the axial movement of the shaft 31 is controlled by the air cylinder 35. Suitable bearing structure (not shown) is provided in the frame rail 21 for accommodating the rotation and axial movement of the shaft 31.

The bending device 24 has a hub 36 rotatably mounted in a suitable bearing (not shown) in the frame rail 20, and is also capable of both rotation and axial movement. The mechanism for providing this is similar to that described in connection with the shaft 31. The hub 36 is mounted on a shaft 37 which is positioned axially by the air cylinder 38, and rotatively by the air cylinder 39 functioning in conjunction with the rack 40 and the gear 41. The gear 41 is slidable, but non-rotatable with respect to the shaft 37. The machine will additionally in- 3 clude locating devices (not shown) for maintaining the axial position of the gears 32 and 41, and for supporting the cylinders 34, 35, 38 and 39 in fixed positions with respect to the frame.

The bending device 24 is provided with a disc-shaped portion 42 from which the bending arm 26 extends. The disc portion 42 is received within the gap of a C-shaped holding member 43, which is slidably supported in the bracket structure 34 mounted on the frame rail 20. The gap in the holding member 43 which engages the disc portion 42 of the bending device is considerably wider than the thickness of the disc portion 42, resulting in a lost-motion relationship between the axial movement of the bending device and the position of the holding member 43. As the bending device moves from the FIG- URE l to the FIGURE 2 position, the disc portion 42 moves into contact with the surface 45 defining one side of the gap. After contact has been made at this surface, the holding member 43 moves to the right with the bending device 24 into the FIGURE 2 position. Referring to FIGURE 10, the holding device 43 has a slot 46 disposed to engage the wire workpiece 22 as the machine moves from the FIGURE 1 to the FIGURE 2 position. During this movement, the bending arm 26 will be psitioned so that it will move across the bight 25 in a position sufiiciently above the wire to eliminate interference, as shown in FIGURE 4. It is preferable that the bending arm 26 be provided with a stop abutment 47 to engage the free end 48 of the wire, as shown in FIG- URE 3, to hold it against expansion as the bending operations proceed.

The accurate maintenance of the position of the wire workpiece 22 during the bending operations is very important, and the jaw assembly 23 has special provision for assisting in maintaining the placement of the bight 25. The pin 49 is fixed with respect to the jaw member 28, and is received within a clearance hole in the opposite jaw 27. This pin engages the transverse portion 50 of the wire as best shown in FIGURE 3, and has the effect of eliminating accumulations of tolerance in the initial bending of the wire workpiece 22 into the coplanar serpentine configuration. The function of the pin 49 is supplemented by that of the pin 51 in the holding member 43, and the combined effect of these pins is to accurately position the bight end of the wire workpiece in a left-right direction, as viewed in FIGURE 3. The location of this part of the workpiece in the transverse direction (vertically on the FIGURE 3 representation) is obtained by the combined effect of the pin 52 on the jaw assembly 23 and the base of the slot 46 in the holding member 43. When the components of the machine are in the operating position shown in FIGURE 2, the bight end of the wire workpiece 22 is thus accurately confined in all directions. The pin 52 is mounted in the same manner as the pin 49, and may be considered as fixed with respect to the jaw 28, and moving within a clearance hole in the opposite jaw 27.

When the jaw assembly 23 and the bending device 24 move into the FIGURE 2 position, the machine undergoes a further preparation for the first bending operation. A C-shaped clamping device 53 is shoved into engagement with the jaw assembly 23, as best shown in FIG URE 7. The clamping device is positioned by the upper and lower guide rails 54 and 55, respectively, and movement along these rails is generated by the piston rod 56 of the air cylinder 57. This air cylinder is mounted on a bracket 58, which (together with the guideway structure) is fixed with respect to the frame rail 21. The efiect of the engagement of the clamping member 53 with the jaw assembly is to lock the rotative position of the jaw assembly so that the bending operation can proceed to a greater accuracy than would be practical through the mere control of the vertical position of the rack 33.

The machine having achieved the position of the components thus far described, the first bending operation proceeds. The axis of rotation of the bending device 24 is located on the center of curvature of the edge 59 of the jaw 28. Rotation of the bending device 24 in a counterclockwise direction (as viewed in FIGURE 4) will proceed to wrap the bight 25 of the wire 22 around the edge 59 into the configuration shown in FIGURE 6. Referring to FIGURE 8, the surfaces 60 and 61 register with respect to the surfaces 62 and 63 on the bending arm 26 and jaw member 28 to produce the desired configuration in the bight 25. FIGURE 6 represents the completion of this bending operation, after which the device is relaxed to the position shown in FIGURE 8. This permits the bending device 24 to be retracted into the FIGURE 1 position preparatory to the second bending operation. With the bending arm 26 clear of the bight 25, it now becomes possible for the jaw assembly 23 to rotate in a clockwise direction, as shown in FIGURE 4, approximately degrees to the position of FIGURE 11. This action has the effect of bending the wire workpiece from the FIGURE 14 to the FIGURE 15 condition, which is essentially a twisting action about the transverse portion 50 of the wire workpiece. It should be noted here that the placement of the pins 49 and 51 is such as to place the wire workpiece with its axis approximately on the axis of rotation of the jaw assembly 23. When this has been accomplished, the jaw assembly 23 can be opened and retracted to the FIG- URE 1 position, releasing the wire workpiece either for subsequent bending operations at other positions, or for discharge from the machine.

Under some conditions, it may be desirable to supplement the principal operating structure of the machine with some guiding devices to facilitate the initial downward placement of the spring elements in the FIGURE 1 position. The holding member 43 may be provided with a vertical piece 64 having a cam surface 65 for shifting a possibly displaced wire laterally enough that it can be received in the slot 46. A deflecting member can also be placed over the bending device 24, if necessary. The details of these auxiliary items will vary with the type of variations encountered in the original serpentine form of the wire 22.

The machine will also include a conventional system for activating the various moving components in sequence. This system can be based either on a timing device, or on a sequence-completion arrangement in which the completion of each operation energizes the machine in the succeeding operation. Suitable standard detection devices such as switches or valve actuators can be used in the latter system, mounted so that the machine actuates them as it completes the operations.

The particular embodiments of the present invention which have been illustrated and discussed herein are for illustrative purposes only and are not to be considered as a limitation upon the scope of the appended claims. In these claims, it is my intent to claim the entire invention disclosed herein, except as I am limited by the prior art.

I claim:

1. A wire-bending machine, comprising:

a frame;

a jaw assembly having a forming surface on one side thereof, said jaw assembly being rotatably mounted in said frame;

a bending arm mounted in said frame opposite said jaw assembly 'for rotation in a limited sector, said arm extending parallel and eccentric with respect to the axis of rotation thereof, and normally overlapping said jaw assembly in a direction parallel to said axis, the overlapping portions of said arm and jaw assembly being radially spaced from each other to receive a workpiece therebetween, whereby a portion of said workpiece extending from the side of said jaw assembly may be wrapped around and conformed to said forming surface by rotation of said opposite side of said jaw assembly from said bending arm about said axis; and arm.

actuating means for rotating said jaw assembly and References Cited bending arm in sequence. IT D PA N 2. A machine as defined in claim 1, wherein said jaw 5 3 104 685 27 5 1 TE TS 140-71 b1 d b d' bl ax l1 ith i ma 8 assem y an en mg arm are Para 6 la y W 3,256,915 6/1966 Fisher et al. 140 71 respect to each other.

3. A machine as defined in claim 1, wherein said machine additionally includes a clamping device engageable CHARLES LANHAM Prlmary Exammer' with said jaw assembly to lock the same against displace- 10 LOWELL A. LARSON, Assistant Examiner. ment at least during the operation of said bending arm.

4. A machine as defined in claim 1, wherein said ma- US. Cl. X.R. chine additionally includes a holding member on the 7 320

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