US3038505A - Auxiliary tool-adjusting mechanism for wire-forming machines - Google Patents

Description

June 12, 1962v M. G.l cLAY- 3,038,505Y

.I AUXILIARY TOOL-ADJUSTING MECHANISM FOR WIRE-FORMING MACHINES Filed May 15, 1960 2 sheets-sheet 1 95 lo; s

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M. G. CLAY 3,038,505 AUXILIRY TOOL-ADJUSTING MECHANISM FOR WIRE-FORMING MACHINES June l2, 1962 2 Sheets-Sheet 2 Filed May 13. 1960 nlllnllllllla n EEE-EE?" INVENTOR;l MURRAY G. CLAY Avvv.:

3,@3855 Patented June l2, 1962 tice 3,038,505 AUXELIARY TGQL-ADJUSTING MECHiNlSM FOR WIRE-FORMING MACHENES Murray G. Clay, Evanston, El., assigner to The Baird Machine Company, Stratford, Conn., a corporation of Connecticut Filed May 13, 1969, Ser. No. 28,879 3 Claims. (Cl. Mtl-7l) The present invention relates generally to Wire-forming machines, and has particular reference to a machine of the type in which a hardened steel wire is fed from a guide member or quill and caused to impinge against a suitable tool to cause deflection and coiling of the wire as it is fed.

The invention is illustrated herein as embodied in a machine of the type disclosed in my `cci-pending United States patent application Serial No. 705,522, tiled on December 27, 1957 and entitled, Wire Forming Mechanism With Selectively Operable Forming Tools. In such applica-tion, lthere has been disclosed a fully automatic cyclicly operable wire-shaping mechanism which embodies means whereby lengths of spring wire stock from a supply are successively forcibly projected through an elongated coniining bore provided in a guide member or quill and allowed to issue from a discharge orifice at a forming station. At the forming station, a series of wire-forming tools are selectively brought into forming register with the orifice, either singly or in groups of two or more tools, at appropriate times in the machine cycle to produce a predetermined spring form, after which la cut-off knife is caused to sever the completed form from the supply at the orifice. Such a machine cycle is repeated indefinitely.

The ability of a machine of this type to produce, without adjustment, spring forms which are uniform in character, i.e., shape, is dependent upon many factors, any one of which, if varied to the slightest degree, will contribute to a departure in the spring shape from a norm.

Among the factors which thus may contribute to departures in spring shape are variations in hardness of the wire stock as affected, for example, by the amount of cold working or heat treatment employed in its manufacture, variations in grain structure, variations in the carbon content or in the alloy constituents at different regions along the wire stock, changes in room temperature and consequent expansion or contraction of machine parts :as well as the Wire stock itself, the effect of wear on the wire-forming tools, changes in ambient, humidity, varia-tions in the character of the lubricant employed on the spring stock, fluctuations in line voltage and its effect on the driving rate of the machine, and other factors too numerous to mention.

In lthe successive and rapid production of springs, the effect of these factors on spring shape is capable of 'being detected visually by observing a change in `the position in space of the distal end region of a spring shape during the short dwell period which exists while the cutoif knife is swinging to-ward `t-he quill to effect vthe severing operation. For example, in the manufacture of helical coil springs having terminal loops or hooks which extend diametrically .across the spring body at each end of the spring, it may be specified that these two loops be coplanar. Since ythe amount of wire fed through the quill for each operation is exactly the same, an iniinitesimal change in the diameter of the coiled body of the spring occasioned by any of the various factors enumerated above, will give to or subtract from each coil convolution an increment of wire length which is ap proxirnately three and one-seventh (1r) times the change in diameter of the coil. Multiplied by the number of coil convolutions, the shortage or excess of wire assigned -to the creation of the last convolution by the forming tool will result in a change in direction of extent of the first terminal loop at the time of cut-offu If it has been specified that the terminal loops be coplanar, or that they bear any other definite directional relationship to each other, a deviation in the direction of the rst terminal loop at the time of cut-off Will obviously render lthe spring unsatisfactory `for failure to meet loop specifications. However, irrespective of loop specifications, such a change in spring diameter will invariably result in a change in spring load which is a function of the square of the coil diameter.

The presen-t invention is designed to overcome the above-noted limitations that are attendant upon the performance of corrective measures such as are currently employed for attaining consistency of spring shape over a given period or" machine operation, and toward this end, the invention contemplates the provision of a novel tool-adjusting mechanism by means of which the fixed distance existing between rthe operative coiling point on the tool and the orifice of the quill from which the spring wire stock issues, may be varied within very fine limits, and having been varied, held constant throughout successive body coiling operations, such adjustment being available to the operator at all times and while the machine is running.

The provision of a tool-adjusting mechanism of the character briefly outlined above being among the principal objects of the invention, it is a further object to provide such an adjusting mechanism which may be installed as original equipment or readily applied to existing springceiling machines.

Numerous other objects and advantages of the invention, not at this time enumerated, will become more readily apparent as the nature of the invention is better understood.

In the accompanying two sheets of drawings `forming a part of this specification, one illustrative embodiment of the invention has been shown.

In these drawings:

FIG. l is a fragmentary perspective view, somewhat schematic in its representation, of a portion of a Wire-forming machine in the vicinity of the wire-forming station thereof, and showing the improved auxiliary tool-adjusting mechanism of the present invention operatively applied thereto;

FIG. 2 is an enlarged side elevational view, partly in section, of portions of the disclosure of FIG. l which are pertinent to the present invention;

FIG. 3 is a top plan view, partly in section, of the structure shown in FIG. 2; and

FIG. 4 is au enlarged perspective View, schematic in its representation, and illustrating the manner in which the position of the terminal loop of a captive spring may vary in accordance with `spring body diameter.

Referring now to the drawings in detail, and in particular to FIG. `l, the novel adjusting mechanism of the present invention has been designated in its entirety at 10 and it is shown as being operatively applied to a wireforming machine of the type shown and described in my co-pending application Serial No. 705,522, referred to above. This environment for the adjusting mechanism 10 is purely exemplary since the mechanism is capable, with or without modification, of being applied to other types of wire-forming machines. Briefly, the adjusting mechanism 1t) assumes the form of an adjustable limit stop or abutment l2 which is movably mounted for extremely small displacements on a stationary part of the machine framework, and the movements of which may manually be controlled by means of an operating lever assembly 14 conveniently accessible to the hand of an operator. The adjustable abutment i2 is provided for aosasos the purpose of limiting the operative stroke of one of a series of stop screws, one of which has been shown at l5, and each of which is movable in unison with a respective forming tool. By limiting the throw of the stop screw, the position of the forming tool during spring-coiling operations is fixed so as to impart a definite and fixed curvature to the deliected wire stock to thus control the diameter of the spring body undergoing coiling, all in a manner that will be made clear presently.

For a full disclosure of a spring-forming machine of the type fragmentarily illustrated in FlG. l as an environment for the present invention, reference may be had to my above-mentioned (zo-pending application. It is deemed suicient for purposes of description herein to state that such a machine is predicated upon the positive forcing of successive lengths of spring wire stock W from a supply through an elongated confining bore 18 provided in a guide member or quill Ztl while simultaneously driving the wire as it issues from the orifice 22 at the forward end of the bore against a series of wireforming tools, two of which have been shown at 24 and 26, respectively, and which are selectively brought into forming register with the end of the bore at appropriate times in the machine cycle to produce a predetermined spring form7 and thereafter, severing the wire by means of a cut-off knife 28, and repeating the machine cycle immediately after the severing operation without stopping the machine.

The spring-forming mechanism illustrated herein is so designed that the tools 24 and 26 may be moved in a controlled manner under the influence of a Cain-controlled mechanism, one for each tool. Only the mechanism. for controlling the movements of the tool 24 has been shown in FlG. l, but is will be understood that similar mechanism is employed for the tool 28. The cam-control mechanism shown herein includes a cam disk on which there rides a follower arm 32 which is pivoted as at 34 to a portion of the machine framework and which transmits its motion through a link 36 to a crosshead 38 carried at one end of a tool holder 40 which is pivoted as at 42 medially of its ends, and which carries the tool 24 at its other end. The tool holder 40 is springbiased as at 43 in such a direction that the tool 24 is normally urged into cooperating register with the orifice 22 of the quill 20. The tool 24 is adapted to be moved toward and away from the orifice 22 under the influence of the cam disk 30. An adjusting knob 44 and cooperating lock nut 46 control the effective length of the link 36 while a similar adjustment knob 48 and lock nut 49 control the effective length of the stop screw 16. This latter stop screw is designed for engagement with a stationary portion of the machine to hold the tool stationary and control its distance from the orifice 22 at such time as the tool 24 is effecting a spring-ceiling operation.

Movement of the tool 26 is effected under the control of mechanism similar to that described above in connection with the tool 24. None of this latter mechanism appears in FIG. 1, it having been omitted Afor the sake of clarity. However, portions thereof appear in =lFlGS. 2 and 3, and similar characters of reference have been applied to the corresponding parts thereof to avoid needless repetition of description.

The wire stock W is fed to the quill 29 by feed rollers 51 and 53, respectively. The wire stock leaving the feed rollers is forced through a central bore 55 provided in a composite guide member 57.

Referring now, additionally, to FIGS. 2 and 3, the stop screw 16, which regulates the effective distance between the tool 24 and quill orifice 22, is designed for engagement with the forward end of the previously mentioned adjustable abutment 12. This abutment is in the form of an abutment screw which is threaded throughout its entire length and is threadedly received in an opening 52 CII ,A fr provided in the fixed front plate Sti. The abutment screw l2 projects rearwardly of the plate 5@ an appreciable distance and it is threaded through one end region of a tiltable binding or rocker plate 54 which is disposed rearwardly of the plate Si) and which is provided with a medial fulcrurn rib 55 adapted to bear against the rear face of the plate 5t?. rhe other end of the binding plate 54 threadedly receives therein one end of a tensioning screw 58 which extends through a hole 6d provided in the front plate 5f). From the above description, it will be seen that by progressively tightening the tensioning screw 5?, increasing degrees of frictional retardation will be applied to the abutment screw 12 resisting turning movement thereof.

In order to adjust the abutment screw l2 in either direction, the manipulating lever assembly 14 is provided. rfhis assembly includes a hub plate 64 through which the screw 12 is threaded as at 6e, and which may be locked in any desired angular position thereon by means of a lock nut 67. One end of a manipulating handle proper 6% is secured to the distal end of the hub plate by means of a clamping bolt 7d. The purpose of the tensioning mechanism previously described is to inhibit pendulous swinging movement of the handle proper 68, which may be initially adjusted to any desired inclination which is convenient to the operator and left in a position where a few degrees of forcible swinging movement thereof in either direction will embrace all of the adjustments required of the abutment screw l2. The inclination of the handle 68 may be adjusted to accommodate the preference of the operator by loosening either the lock nut 67 or the clamping bolt '70.

When it is desired to displace the abutment screw 12 axially in either direction to diminish or extend the throw of the stop screw in, it is merely necessary for the operator to swing the handle 68 in one direction or the other. Preferably, the threads associated with the abutment screw l2 are coarser than the threads associated with the adjustment yknob 48 since it is contemplated that very small increments of swinging movement of the handle 68 shall impart appreciable adjustment movement of the tool 26 toward and away from the quill orifice 22.

An exemplary situation requiring the use of the present auxiliary tool-adjusting mechanism for shape-corrective purposes has been schematically illustrated in FIG. 4. ln this view, a completed spring S, having a generally cylindrical helically coiled body consisting of fifteen closely-wound convolutions, is shown as being held captive on the quill 2li immediately prior to the cut-olf operation by the knife 28. The spring S is provided with a crossbar 82 at each end of the body 80 which merges with a terminal loop or hook 84. The axis X-X represents the direction of extent of the distal crossbar and loop during the dwell period which exists during each machine cycle ywhile the knife 28 is swinging toward the quill 2u to perform its cut-off operation.

Let it be assumed for purposes of discussionV that, in making a spring having a diameter of 0.20 inch, for example, due to a change in wire hardness, ambient temperature, or any of the numerous factors previously cited, which may contribute to a shift in the diameter of ceiling effected by the tool 26 during that portion of the machine cycle in which the body 3G is being formed, the overall diameter d of the spring body 80 increases by .005 inch. Since exactly the same amount of wire is fed by the feed rollers 5l, 53 during each machine cycle, at the end of each spring-forming operation immediately prior to spring cut-oft', the amount of wire stock lacking for the production of a normal spring body will, of course, be 31/7 times .005 inch times fteen, or approximately .235 inch. Due to this shortage of wire, the diametrical direction of the distal crossbar and loop will be angularly displaced as indicated by the axis Z-Z and resulting in a departure angle 0. The magnitude of the angle 6 will, for the change in diameter, be approximately Such a shift in the position of the crossbar and loop is readily visible to the operator.

Upon detecting the discrepancy in the angular displacement of the crossbar and loop, the operator may bring the formation of the springs back to normal by merely swinging the lever 68 in one direction to move the abutment screw 12 a slight distance in a direction such that the operative wire-engaging surface 2S of the forming tool 24 may move closer to the quill orifice 22 and increase the angle of deflection of the wire stock and thus decrease the diameter of the spring body 80 a commensurate amount. The operator need make no mental calculations and his manipulation of the lever 68 may be an empirical matter based upon his observation in a change in the direction of the axis YY. When this axis is restored to its normal direction, the operator will be apprised of the fact that springs of the correct diameter are being made by the machine. Obviously, if the position of the crossbar 82 and loop 84 shifts to a position such as is indicated by the axis Y-Y, this will be an indication that springs of undersize diameter are being formed and the operator will shift the position of the handle 68 in the opposite direction so as to cause the abutment screw 12 to position the wire engaging surface of the tool further away from the orifice so as to coil a spring body of slightly greater diameter.

Since certain obvious changes may be made in the illustrated device without departing from the scope of the invention, it is intended that all matter contained herein be interpreted in an illustrative and not a limiting sense.

Having thus described the invention what I claim as new and desire to secure by letters patent is:

l. In an apparatus for progressively shaping Wire stock into predetermined spring form as the stock emerges forwardly from a feed orifice, a frame, a wire guide having a central longitudinal wire-confining bore extending therethrough and terminating in a feed orifice, means for repeatedly forcibly impelling exact predetermined lengths of the wire stock through said bore in a direction to cause the wire stock to issue from said orifice, a wireengaging and forming tool movably mounted on the frame in the vicinity of said orifice, means for moving said tool toward and away from the orifice, said tool moving means and tool being resiliently biased toward said orifice, a limit stop abutment positioned in the path of movement of the tool moving means and engageable with the latter for limiting the extent to which said tool may swing toward said orifice, and operator controlled means movable independently of and unaffected by the movement of said tool moving means for shifting the effective position of said abutment in opposite directions.

2. In an apparatus for progressively shaping continuous wire stock into predetermined spring form as the stock emerges forwardly from an orifice, a stationary framework, a `wire guide mounted on said framework and having a central longitudinal wire-confining bore extending therethrough and terminating in a feed orifice, means for repeatedly forcibly impelling exact predetermined lengths of wire stock through said bore in a direction to cause the wire stock to issue from the orifice, a wire-engaging and forming tool movably mounted in the vicinity of said orifice for movement toward and away from the latter, means for moving said tool in timed relationship with said wire impelling means, sai tool being resiliently biased toward said orifice, an adjusting screw mounted for movement with the tool and adjustable for controlling the degree of movement of the tool toward the orifice, a limit stop abutment movably mounted on the framework and positioned in the path of movement of the adjusting screw and engageable with the latter for limiting the extent to which said tool may move toward the orifice, and manually operable means operable independently of and unaffected by the movement of said tool moving means for imparting limited increments of motion to said abutment in opposite directions.

3. In an apparatus for progressively shaping continuous wire stock into predetermined spring form as the stock emerges forwardly from an orice, a stationary framework, a wire guide mounted on said framework and having a central longitudinal wire-confining bore extending therethrough and terminating in a feed orifice, means for repeatedly forcibly impelling exact predetermined lengths of wire stock through said bore in a direction to cause the wire stock to issue from the orifice, a wire-engaging and forming tool movably mounted in the vicinity of said orifice for movement toward and away from the latter, means for moving said tool in timed relationship with the operation of said Wire impelling means, said tool being resiliently biased toward said orifice, an adjusting screw mounted for movement with the tool and adjustable for controlling the degree of movement of the tool toward the orifice, said framework including a member having a threaded opening therein, a limit stop abutment screw threadedly received in said opening and having an end thereof positioned in the path of movement of said adjusting screw and engageable with the latter for limiting the extent to which the tool may approach said orifice, a torque-applying handle secured to said abutment screw operable independently of and unaffected. by the movement of said tool moving means for turning said abutment screw, and means frictionally engaging said abutment screw for inhibiting pendulous swinging movement of the torque-applying handle.

References Cited in the file of this patent UNITED STATES PATENTS 1,250,252 Wadsworth Dec. 18, 1917 2,073,343 Heilman Mar. 9, 1937 2,077,243 Leal Apr. 13, 1937 2,085,570 Blount et al June 29', 1937 2,744,546 Williams May 8, 1956

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