US3779058A

US3779058A - Spring forming apparatus

Info

Publication number: US3779058A
Application number: US00244407A
Authority: US
Inventors: H Norman
Original assignee: Individual
Current assignee: Leggett and Platt Inc
Priority date: 1972-04-17
Filing date: 1972-04-17
Publication date: 1973-12-18
Anticipated expiration: 1990-12-18

Abstract

A spring forming apparatus of the type wherein a wire is twisted substantially circumferentially between an isolator wheel and a feed wheel mounted for planetary motion on a revolving platen. The improvements include the use of a pinch wheel cooperating with a single feed wheel to grip the wire adjacent its exit from the twist mechanism, together with a simplified planetary drive system in which a portion of the drive assembly is bearing mounted to a cylindrical journal at the wire input end of the platen cage.

Description

United States Patent [1 1 Norman SPRING FORMING APPARATUS [75] lnventor: Harry H. Norman, Los Angeles,

Calif.

[73] Assignee: Stephen Baliski, Gardena, Calif. a

part interest [22] Filed: Apr. 17, 1972 [21] Appl. No.: 244,407

[52] US. Cl 72/66, 72/140, 72/145, 140/149 [51] Int. CL... ..B21f3/02, 8211 3/04, B2lf 3/10, B2lf 7/00, 8211 23/00, B2lf 35/00 [58] Field of Search ..29/173; 72/66, 135, 72/140, 141,142,145;140/89,149

[56] References Cited UNITED STATES PATENTS 1,892,501 12/1932 Burd et a1. 72/145 2,162,355 6/1939 Parrish et al... 72/145 2,567,537 9/1951 Workman 140/149 2,631,639 3/1953 Palmer 72/66 VAQIABL &

SPEED DQIVE Dec. 18, 1973 Beaumont 72/66 2,927,744 3/1960 Nye et a1. 72/66 2,983,301 5/1961 Leclahart..... 72/135 3,541,828 11/1970 Norman.... l40/l49 3,570,291 3/1971 Shiguma 140/149 Primary Examiner-Richard J. Herbst Assistant Examiner-12. M. Combs Atturney-Allan M. Shapiro [5 7] 7 ABSTRACT A spring forming apparatus of the type wherein a wire is twisted substantially circumferentially between an isolator wheel and a feed wheel mounted for planetary motion on a revolving platen. The improvements include the use of a pinch wheel cooperating with a single feed wheel to grip the wire adjacent its exit from the twist mechanism, together with a simplified planetary drive system in which a portion of the drive assembly is bearing mounted to a cylindrical journal at the wire input end of the platen cage.

12 Claims, 7 Drawing Figures PAIfmgunzmems sum zur 3 Y PGO QMM W m M453,

PAIENTEB new 8191s saw 2 or 3 PATENTEU 0E0: a 1915 SHEET 3 0f 3 1 SPRING FORMING APPARATUS BACKGROUND OF THE INVENTION wheel and planetary feed wheel at the output.

2. Description of the Prior Art The inventors U.S. Pat. 'No. 3,541,828 entitled SPRING FORMING APPARATUS AND PROCESS describes the manufacture of springsby circumferen- .tially twisting an isolated length of wire to less than the elastic limit, then releasing the wire to form the spring. Springs. so formed may exhibit greater working stress than obtainable with springs of the same material and index but fabricated by prior ar mandril wrapping techniques. Less wire is needed to form a spring of the sameworking stress. In the bedding industry, where many springs are used, substantial reduction in final product cost may result. One object of the present invention is to provide an improved apparatus for forming coil springs using this patented process.

The same patent also discloses apparatus for forming such springs. Wire from a spool is fed via an isolator wheel to a revolving platen carrying a planetary feed wheel. The wire is retrained between the feed wheel and a metal guide band which is held taught by a separate bias wheel on the platen. As the platen revolves,

the section of wire between the isolator wheel and the feed wheel is twisted; the wire emergent from the feed wheel releases into a coil spring. Excellent performance is achieved using this apparatus. However, continuous'flexing limits the lifetime of the guide band, necessitating periodic replacement. Another object of the present invention is to eliminate both the wire restraining guide band and the associated bias wheel.

The patented apparatus employs an oil immersed, double planetary gear system carried by the platen and facilitating dynamic control of the planetary ratio,i.e., the relative rotation rate of the platen and the feed wheel. A feedback system incorporating such planetary ratio control insures that the spring does not rotate as it emerges from the machine. The gear system is complex, and provision must be made to compensate for oil driven toward the platen periphery by centrifugal force..Thus it is a further object of the invention to provide a spring forming apparatus having a simplified planetary drive mechanism using neither complicated sets of gears nor oil immersion, yet permitting dynamic control of the planetary ratio.

SUMMARY OF THE INVENTION platen. A belt connects the feed wheel shaft to a drive pulley mounted in bearing'relationship with the cage cylindrical journal and driven at a controllable rate. As .the platen revolves, the independent rate and direction of rotation of the drive pulley establishes the planetary ratio.

' 2 Wire from the isolator wheel enters the platen cage through the cylindrical journal and is guided by a slot wheel through the platen to the feed wheel. A pinchv wheel engages the wire against the feed wheel periphery to isolate the twisting forces from the emergent wire which, when relieved, assumes a coil shape. Use of the pinch wheel, optionally in conjunction with a set of idler rollers at the feed wheel periphery, eliminates the need for a guide band and its associated bias wheel.

BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of the invention will be made with reference to the accompanying drawings wherein like numerals designate corresponding elements in the several figures.

FIG. 1 is a simplified pictorial view of a spring forming apparatus in accordance with the present invention.

FIG. 2 is an end view of the apparatus of FIG. 1, showing details of the platen, feed wheel and pinch wheel.

FIG. 3 is a transverse sectional view of the spring forming apparatus, as seen along the line 3-3 of FIG. 1.

FIG. 4 is a fragmentary sectional view of the feed wheel and pinch wheel, as seen along the line 44 of FIG. 2.

FIG. 5 is a fragmentary side view of the pitch control wheels, as seen along the line 55 of FIG. 2.

FIG. 6 is a fragmentary end view of another embodiment using idler rollers in conjunction with the feed wheel.

FIG. 7 is a fragmentary sectional view of the feed wheel and a typical idler roller, as seen along the line 7-7 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in alimiting sense, but is made merely for the purpose of illustrating the general principles of the invention since the scope of the invention best is defined by the appended claims.

Operational characteristics attributed to forms of the invention first described shall also be attributed to forms later described, unless such characteristics are obviously inapplicable or unless specific exception is made.

Referring now to the drawings, the inventive apparatus 10 (FIG. 1) forms a wire 11 supplied from a spool or other source into a coil spring 12. The spring 12 is produced by substantially circumferentially twisting the section of wire 11a between an isolator wheel 13 and a feed wheel 14 mounted for planetary motion on a revolving platen is. A pinch wheel 16 presses the wire 11 against the feed wheel periphery 14a to isolate the twisting forces from the wire 1 1b emerging from the feed wheel 14. This released wire 11b assumes a coil shape as a result of the imparted circumferential twist.

The apparatus 10 is mounted on a stationary frame 20 having a horizontal table 200 to which the isolator wheel 13 is mounted by a vertical shaft 21. The frame 20 also supports a generally conical platen cage 22. The platen 15 forms the base of the cage 22 and is connected by rigid cage members 23 to a cylindrical journal 24 at the apex of the cage 22. The platen 15 is sup ported by a frame member 20b via a bearing 25, and

the journal 24 is mounted by a bearing 26 to a frame member c. This arrangement permits the entire platen cage 22 to revolve about the common axis through the journal 24 and the platen 15, when driven by a belt 27 engaging a groove 28 at the periphery of the platen 13. Preferably, the common axis of the cage 22 is tangential to the isolator wheel 13.

A simple assembly 30 is used to drive the planetary feed wheel 14. The feed wheel 14 is affixed to a shaft 31 (FIGS. 1 and 3) extending through the platen 15, a cage member 23 and a support bracket 32 (omitted in FIG. 1 A belt 33 connects a pulley 34 on the shaft 31 to another pulley 35 mounted in bearing relationship about a portion 24a of the cage cylindrical journal 24. As the platen cage 22 revolves in a counterclockwise direction (arrow 36 in FIG. 1) the feed wheel 14 will rotate about the shaft 31 axis in a clockwise direction (arrow 37).

The planetary ratio (i.e., the number of rotations of the feed wheel 15 for each revolution of the platen 13) is determined by the direction and rate of rotation of the pulley 35. The pulley 35 itself is driven via a belt 38 and a variable spped drive 39 by a motor 40. The motor 40 also may drive the platen cage 22 directly via the platen belt 27. Adjustment of the variable speed drive 40 controls the planetary ratio and hence the feed rate of the emerging wire 11b. The simplified drive assembly 30 completely eliminates the relatively complicated, oil immersed double planetary gear system described in the above mentioned U.S. patent. The wire section Ila from the isolator wheel 13 is directed into the cage 22 by a pair of coplanar drive wheels mounted on support'brackets 46 projecting rearwardly from the cylindrical journal 24. The wire 11a thence goes through the interior 24b of the journal 24 and around a peripheral portion of a slot" wheel 47 mounted to the cage 22 by a shaft 48 having an axis in a plane parallel to the platen 15. A sector 47a of the wheel 47 projects through a slot 49 (FIGS. 2 and 3) in the platen 15 so as to guide the wire 11a into the plane of the feed wheel 14.

In the embodiment of FIG. 1 the wire llb from the slot wheel 47 loops around the feed wheel periphery 14a approximately one and a half times. The pinch wheel 16 has a peripheral groove 16a (FIG. 4) which pinches or presses the wire 11 radially against the feed wheel 14 at the point 51 where the wire 11b emerges from the feed wheel 14. The bias force is provided by a compression spring 52 acting against a lever arm 53 carrying the shift 54 of the pinch wheel 16.

Preferably the wire 11b should emerge from the pinch wheel 16 in a line tangential both to the spring 12 being formed and to the feed wheel 14. To fabricate springs 12 having different diameters, the pinch wheel 16 may be mounted (FIG. 2) so as to allow arcuate adjustment of the contact point 51. Thus, the lever 53 is pivotally supported at 55 to a bracket 56 adapted to pivot about the axis of the feed wheel shaft 31. An arcuate guide 57 on the platen 15 receives a nut or other fastener 58 at the outer end 56a of the bracket 56. By loosening the nut 58 and pivoting the bracket 56, the pinch wheel 16 can be positioned to the required point 51. The pinch wheel 16 isolates the emergent wire section 11b from the circumferential twisting forces imparted by revolution of the platen 15. The isolator wheel 13 (FIG. 1) isolates these twisting forces from the portion of wire 11c entering from the source. To

this end, the wire 11 forms one or more loops around the periphery of the isolator wheel 13. Appropriate tension of the wire section 1 1a between the isolator wheel 13 and the pinch wheel 16 is insured by a pair of drag wheels 60 mounted on the table 20a on opposite sides of the wire 11 and biased to provide the necessary drag. An offset pair of cast killer rollers 61 also may be used to break the cast of the wire from a spool or other source, thereby aiding uniformity of the produced spring 12.

The twisted wire 11b emerging from the feed wheel 14 assumes a coil shape. However, the natural pitch and/or diameter may differ from the desired value. Accordingly, a pitch control wheel assembly 64 (FIG. 5) mounted on the bracket 56 limits the pitch assumed by the wire 11b. The wire 11b is guided by the rollers 65 through an angle established by a lever arm 66 carrying the wheel 65' and adjusted by a screw 67. A set of diameter control wheels 69 mounted on the platen 15 control the spring 12 diameter. The radial spacing of the rollers 69 with respect to the center of the platen 15 is adjusted to produce springs of larger or smaller diameter. When such adjustment is made, the pinch wheel 16 position is adjusted correspondingly.

As an alternative to looping the wire 11b completely around the feed wheel 14, the arrangement of FIGS. 6 and 7 may be employed. There, several idler rollers 70 guide the wire 11b around a portion of the feed wheel 14. The grooved periphery 70a of each roller 70 is aligned with a wire-receiving groove 14b in the feed wheel periphery 14a. The idler rollers 70 all are mounted on a support bracket 71 fixed to the platen 15. Individual bias springs 72 urge each roller 70 toward the feed wheel 14, and retainers 73 prevent the wire 11a from looping away from the feed wheel 14 between adjacent idler rollers 70.

Use of the feed wheel 14 and pinch wheel 16, with the arrangement of either FIG. 1 or FIG. 7, eliminates wire restraining band and bias wheel, as discussed above.

The apparatus 10 of FIG. 1 is configured to form left handed springs 12. To form right handed springs, the slot wheel 47 is mounted on the side of the platen cage axis opposite that shown in FIG. 1, and the pinch wheel 16 is situated against the lower periphery of the feed wheel 14. Rotation of the cage 22 and the feed wheel 14 is opposite that indicated by the

arrows

36 and 37.

By appropriately controlling the direction and rate of rotation of the drive pulley 35, the spring 12 will emerge from the apparatus 10 without rotation. Such control may be accomplished by a feedback system utilizing a spring rotation sensor (not shown) cooperating with the variable speed drive 39. The belt 33 and the

pulleys

34, 35 may be replaced by appropriate gears. The spring 12 produced by the apparatus 10 may be fed directly to other equipment to be shaped into a bedspring, mattress assembly or the like. Identical right and left hand spring formers 10 may be interconnected to insure simultaneous spring formation. Intending to claim all novel, useful and unobvious features shown or described, the applicant:

I claim 1. Apparatus for forming a spring from a wire supplied from a source, comprising:

a generally conical platen cage having a cylindrical journal at the apex and a platen at the base, said cage being mounted to revolve about the common axis of said journal and base,

a feed wheel affixed to a shaft journaled through said platen parallel to said common axis but spaced therefrom, 7

drive means for rotating said feed wheel shaft via a drive pulley in bearing relationship with said journal,

a pinch wheel on said platen and biased to pinch wire against the periphery of said feed wheel,

a slot wheel mounted in said cage to rotate about an axis generally parallel to said platen, the periphery of said slot wheel projecting beyond said platen,

an isolator wheel spaced from said cage and mounted to rotate only about an axis generally perpendicular to said common axis,

wire from said source looping about the periphery of said isolation wheel, thence through said cylindrical journal, around said slot wheel and around at least a portion of the periphery of said feed wheel to said pinch wheel, revolution of said cage imparting a substantially circumferential twist to the portion of wire between said isolation wheel and said pinch wheel, twisted wire emergent from between said feed and pinch wheels releasing into a coil spring.

2. Spring forming apparatus according to claim 1 wherein said pinch wheel presses said wire at the point where tangentially emergent from said feed wheel, and including means for arcuately positioning said pinch wheel to adjust said point.

3. Spring forming apparatus according to claim 2 wherein said means for positioning comprises an arm mounted to pivot about the axis of said feed wheel shaft, said pinch wheel being mounted on said arm, means for maintaining said arm at a selected arcuate position, and means for biasing said pinch wheel radially toward said feed wheel.

4. Spring forming apparatus according to claim 3 further comprising pitch control wheels mounted on said arm for restraining the pitch assumed by said emergent twisted wire.

5. Spring forming apparatus according to claim 1 wherein said drive means comprises;

a first belt connecting said feed wheel shaft and said drive pulley, and

means for rotating said drive pulley at a selectable rate.

6. Spring forming apparatus according to claim 5 wherein said means for rotating comprises;

a drive motor,

a variable speed drive coupling said drive motor to said drive pulley, adjustment of said variable speed drive controlling the relative rotation rate of said platen and said feed wheel, said relative rate being adjustable so that the spring formed by said apparatus does not rotate.

7. Spring forming apparatus according to claim 6 wherein said drive motor also revolves said platen.

8. Spring forming apparatus according to claim 1 wherein the direction of rotation of said platen establishes whethere said spring is right or left handed, said slot wheel being situated on one side of said common axis for formation of right handed springs and on the other side of said common axis for formation of left handed springs.

9. Spring forming apparatus according to claim 1 further comprising one or more idler rollers positioned about the periphery of said feed wheel to guide said wire thereabout.

10. Spring forming apparatus according to claim 9 wherein said idler rollers all are mounted on a support fixed to said platen, each idler roller being biased radially toward said feed wheel, and retainers between said idler rollers to retain said wire against feed wheel periphery.

11. Spring forming apparatus according to claim 1 together with means for providing slight drag on said wire between said source and said isolator wheel.

12. Spring forming apparatus according to claim 11 together with means for breaking the cast of said wire before entry to said isolator wheel. 1

Claims

1. Apparatus for forming a spring from a wire supplied from a source, comprising: a generally conical platen cage having a cylindrical journal at the apex and a platen at the base, said cage being mounted to revolve about the common axis of said journal and base, a feed wheel affixed to a shaft journaled through said platen parallel to said common axis but spaced therefrom, drive means for rotating said feed wheel shaft via a drive pulley in bearing relationship with said journal, a pinch wheel on said platen and biased to pinch wire against the periphery of said feed wheel, a slot wheel mounted in said cage to rotate about an axis generally parallel to said platen, the periphery of said slot wheel projecting beyond said platen, an isolator wheel spaced from said cage and mounted to rotate only about an axis generally perpendicular to said common axis, wire from said source looping about the periphery of said isolation wheel, thence through said cylindrical journal, around said slot wheel and around at least a portion of the periphery of said feed wheel to said pinch wheel, revolution of said cage imparting a substantially circumferential twist to the portion of wire between said isolation wheel and said pinch wheel, twisted wire emergent from between said feed and pinch wheels reLeasing into a coil spring.

5. Spring forming apparatus according to claim 1 wherein said drive means comprises; a first belt connecting said feed wheel shaft and said drive pulley, and means for rotating said drive pulley at a selectable rate.

6. Spring forming apparatus according to claim 5 wherein said means for rotating comprises; a drive motor, a variable speed drive coupling said drive motor to said drive pulley, adjustment of said variable speed drive controlling the relative rotation rate of said platen and said feed wheel, said relative rate being adjustable so that the spring formed by said apparatus does not rotate.

8. Spring forming apparatus according to claim 1 wherein the direction of rotation of said platen establishes whether said spring is right or left handed, said slot wheel being situated on one side of said common axis for formation of right handed springs and on the other side of said common axis for formation of left handed springs.

12. Spring forming apparatus according to claim 11 together with means for breaking the cast of said wire before entry to said isolator wheel.