US3576120A

US3576120A - Apparatus and method for winding coil springs

Info

Publication number: US3576120A
Application number: US766560A
Authority: US
Inventors: Arnold Peter Levasseur
Original assignee: North American Rockwell Corp
Current assignee: BLISS-SALEM Inc A CORP OF; Boeing North American Inc
Priority date: 1968-10-10
Filing date: 1968-10-10
Publication date: 1971-04-27
Anticipated expiration: 1988-04-27
Also published as: GB1260695A; DE1947723A1

Abstract

A method and apparatus for winding coil springs in which the spring wire is supplied to a bending location at a substantially constant feed rate and is sequentially bent for predetermined periods of time at a first fixed radius of curvature, a first variable radius of curvature, a second fixed radius of curvature, and a second variable radius of curvature, the bending steps being repeated a predetermined number of times and the spring wire then being cut such that a spring having a predetermined number of identical, multiradius coils is formed.

Description

United States Patent Arnold Peter LeVasseur Lakeville, Minn.

Oct. 10, 1968 Apr. 27, 1971 North American Rockwell Corporation Pittsburgh, Pa.

Inventor Appl. No. Filed Patented Assignee APPARATUS AND METHOD FOR WINDING COIL SPRINGS 23 Claims, 7 Drawing Figs.

US. Cl 72/33, 72/132, 72/138, 140/103 Int. Cl ..B2lc 51/00, B2lf3/00, B2lf 1 1/00 Field of Search 72/138,

[56] References Cited UNITED STATES PATENTS 2,455,863 12/1948 Halvorsen 72/138 3,009,505 11/1961 72/33 3,342,052 9/1967 72/138 3,472,051 10/1969 72/138 Primary Examiner-Charles W. Lanham Assistant Examiner-R. M. Rogers Attorneys-George R. Powers and John R. Bronaugh ABSTRACT: A method and apparatus for winding coil springs in which the spring wire is supplied! to a bending location at a substantially constant feed rate and is sequentially bent for predetermined periods of time at a first fixed radius of curvature, a first variable radius of curvature, a second fixed radius of curvature, and a second variable radius of curvature, the bending steps being repeated a predetermined number of times and the spring wire then being cut such that a spring having a predetermined number of identical, multiradius coils is formed.

PATENTEB m2? I97! 3576.120

sum 2 or 3 @WWWV'Q- FIG. 3

PATENTED APR 27 1971 sum 3 0F 3 APPARATUS AND METHOD FOR WINDING COIL SPRINGS This invention relates to the winding of coil springs and, more particularly, to a method and apparatus for winding coil springs having nonuniform radii of curvature. The invention is particularly suited to the winding of coil springs of the type described and claimed by copending Pat. application Ser. No. 711,774, entitled Coil Spring. filed Mar. 8, 1968 in the name of Glenn E. Mather and assigned to the assignee of this invention.

The aforesaid patent application discloses a coil spring adapted for loading in a direction transverse to its coiled or longitudinal axis, each coil of the spring having portions formed on different constant radii joined by relatively short transition portions of varying radii. By controlling the different radii, the spring index, and the spring pitchwith accuracy, springs characterized by a broad range of loaddeflection characteristics, including substantially constant load characteristics, can be produced. Heretofore, it has not been possible to manufacture coil springs of the type taught by the aforesaid patent application in a rapid, efficient and accurate manner.

It is therefore an object of this invention to provide an improved method and apparatus for winding coil springs having nonuniform radii of curvature.

Another object is to provide improved means for automatically producing coil springs of the type disclosed by the aforesaid patent application.

A further object is to provide a rapid, efficient and accurate method and apparatus for making coil springs having nonuniform coil radii and constant pitch.

A still further object of the invention is to provide means capable of automatically producing a wide variety of coil springs in a rapid, efficient and accurate manner.

Yet another object is to provide a method and apparatus for automatically winding springs of the foregoing type and automatically cutting the springs to proper length.

Briefly stated, in carrying out the invention in one form, a spring wire is longitudinally supplied to a bending location at a substantially constant rate and is there sequentially bent at a first fixed radius of curvature for a first period of time, at a variable radius for a second period of time, at a second fixed radius for a third period of time, and at a variable radius for a fourth period of time to form a single spring coil, the first and third periods of time being substantially longer than the second and fourth periods of time. The bending process is repeated a selected number of times to produce a coil spring having a desired number of coils, the spring simultaneously and continuously being stretched along its longitudinal axis to provide a desired constant pitch. The wire is cut after the predetermined number of coils have been formed to form a discrete spring of predetermined length.

By a further aspect of the invention, the wire is supplied at the constant feed rate by supporting and guiding means preferably including a roller engaging the wire, and the wire is bent by forming means including a reciprocable abutment surface movable along the feed axis of the wire and an arbor offset from the feed axis. The wire supplied by the supporting and guiding means strikes the abutment surface and is deflected therefrom around a bending surface and on the arbor, the radius of curvature of the wire being dependent on the axial spacing between the abutment surface and the supporting and guiding means. Means are provided for interconnecting and coordinating the movement of the wire advancing means and the abutment surface such that the nonuniform radii characteristics of the coils can be controlled with accuracy. Automatic cutoff means are also provided for counting the number of coils formed and for cutting the wire when a predetermined number of coils have been formed.

While the invention is distinctly claimed and particularly pointed out in the claims appended hereto, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description when taken in conjunction with the drawing, in which:

FIG. 1 is an exploded perspective view of a spring winding machine incorporating the invention;

FIG. 2 is an enlarged side view of the wire forming means and the wire advancing means of the invention;

FIG. 3 is an enlarged view of the abutment means of FIG. 2 illustrating in solid lines its first end position and in broken lines its second end position;

FIG. 41 is a view taken along viewing line 4-4 of FIG. 3;

FIG. 5 is a perspective view of the means, including a cam and a follower, for reciprocating the abutment surface and a partial view of the means for interconnecting the wire advancing means and the means for moving the abutment surface;

FIG. 6 is an enlarged view of the cam and the follower of FIG. 5, the position of the follow corresponding to the first end position of the abutment surface being shown by solid lines and the position corresponding to the second end position being shown by broken lines; and

FIG. 7 is a side view of an alternative form of the invention.

Referring first to FIGS. 1-3, a spring coiling machine 10 formed in accordance with the invention includes a wire supporting and guiding mechanism 12 for delivering a wire 13 to a coiling location 14, the mechanism 12 including rollers 15 for forcing the wire 13 along a longitudinal axis 16 defined by guide plates 17. At least one of the rollers 15 is driven by an electric motor 18 or other suitable drive means. Adjacent the discharge portion 21 of the guide means 12 is a stationary arbor 22 which is offset laterally below the longitudinal axis 16, the arbor 22 having a smoothly curved bending surface 23 as best shown by FIG. 3 which is substantially tangent to the longitudinal axis 16 immediately adjacent the discharge portion 21 and diverges axially and laterally therefrom to a forward point 25. An abutment surface 27 on a block 28 extends transversely across the longitudinal axis 16 axially spaced from the discharge portion 21. More particularly, the coiling point surface 27 is axially movable between first and second end positions as illustrated by FIG. 3, the first end position illustrated by solid lines being a distance x: from the discharge portion 21, and the second end position illustrated by broken lines being a distance x from the discharge portion 21. With the abutment surface 27 in either of its end positions, or, for that matter, anywhere between its end positions, the wire 13 discharged from the discharge portion 21 will, when once started, be deflected by the coiling point 27 out of the longitudinal axis 16 into a curved configuration. Actually, it is desirable that the initial deflection of the wire 13 be directed such that the wire is bent around the bending surface 23. When the abutment surface 27 is in its first end position, the wire 13 will be bent at a first constant radius, and when the surface 27 is in its second end position, the wire will be bent around the surface 23 at a second constant radius, the second constant radius being larger than the first constant radius since the distance 1 is larger than the distance x,. In the preferred embodiment of the invention, the ratio of the distance x to the distance x, is 1.422 to 1. It will, of course, be obvious to those skilled in the art that wire bent while the surface 27 is at any position between its end positions will have a radius of curvature somewhere between the radii of curvature at the end positions.

In accordance with the present invention, the electric motor 18 and the rollers 15 advance the wire 13 at a substantially uniform rate to the forming means adjacent the discharge portion 21, and the abutment surface 27 is moved between its end positions in a predetermined manner. More particularly, the surface 27 is sequentially maintained in its first end position for a first predetermined period of time, moved to its second end position during a second predetermined period of time, maintained in its second end position for a third predetermined period of time, and moved to its first end position during a fourth predetermined period of time. A single coil formed in this manner will have a first portion of relatively small constant radius formed when the abutment surface 27 is in its first end position, a portion of relatively large constant radius formed when the surface 27 is in its second end msition, and portions of varying radius formed when the abutment surface 27 is being moved between its end positions. By scheduling the movement of the surface 27 that the first and third time periods are much longer than the second and fourth time periods, the constant radius portions may be made much longer than the variable radius portions since the wire is supplied by the rollers at a constant rate.

Referring now to FIG. 3, it will be seen that the individual coils are bent inthe plane of the drawing such that the coiled axis of the resulting spring will be normal to the plane of the drawing. To provide a constant spring pitch, an adjustable member 30, commonly known as a pitch tool, having a flat surface 31 thereon laterally spaced, as best shown by FIG. 4, a distance x from the axis 16 is provided, the spring coils being directed across the surface 31 after being deflected by the surface 27. The function of the surface 31 is to longitudinally stretch the coils along the coiled axis to produce a desired pitch. If it is desired to vary the pitch, the offset distance x may be adjusted by suitable adjusting means, the screw 34 representing such means. With reference to FlGS. 3 and 4, it will be noted that the arbor surface 23 and the pitch tool surface 31 are mutually perpendicular, the arbor surface 23 extending axially beyond the forward edge 35 of the member 30 toward the coiling point surface 27.

Referring now to FIGS. 2 and 5, the block 28 upon which the abutment surface 27 is located is mounted on the outer end 40 of a lever 41 secured at its other end 42 to a rotatably mounted axle 44, the connection between the lever 41 and the axle 44 being at right angles. Adjustment screws 46 and 47 are provided for limiting the angular movement of the lever 41, the surface 27 being in its first end position when the lever 41 is in engagement with the screw 46 and in its second end position when the lever 41 is in engagement with the screw 47. Since the total movement of the surface 27 is quite small relative to the length of the lever 41, motion of the surface 27 may be described as being translational in character, and the surface 27 may be said to be reciprocated between its end positions. The axle 44 is connected at right angles at its other end to a lever 50 supporting a rotatable cam follower 51 at its remote end 52. The cam follower 51 rides on the periphery of a generally circular cam 53 fixed to a rotatably mounted shaft 54. A tension spring 55 along with the pressure of the wire 13 on the surface 27 biases the cam follower 51 into engagement with the periphery of the cam 53.

As illustrated by HO. 6, the cam 53 has a first set of constant radius peripheral portions 56 peripherally spacedapart around the earn, the radius R of these portions 56 being selected to move the abutment surface 27 to its first end position whenever the cam follower 51 is in contact with one of these portions 56. A second set of constant radius peripheral portions 58 are alternated with the portions 56 about the periphery of the cam 53, the radius R of these portions 58 being selected to permit the abutment surface 27 to move its second end position whenever the cam follower 51 is in contact with one of these portions. The first and second sets of

portions

56 and 58 thus constitute an even number of constant radius portions interconnected by an even number of relatively short transition peripheral portions 60. By making the angular extents of the

portions

56 and 58 large relative to the portions 60 and by rotating the cam 53 at a constant rate, the abutment surface 27 will be reciprocated in the manner described above, dwelling at its end positions a much longer time than utilized in moving between its end positions. As illustrated, the portions 56 have twice the angular extent of the portions 58, the result being that the small radius portions of the coils formed will have substantially twice the length of wire as the large radius portions. Similarly, the portions 56 have approximately four times the angular extent of the transition portions 60. It will, of course, occur to those skilled in the art that the relative angular extents can be different to provide different relative lengths of wire in the different radius portions ofthe coils.

Attention is now directed to FIGS. 1 and 6. To assure coordination of movement of the wire 13 along the longitudinal axis 16 and reciprocation of the surface 27, the shaft 54 carrying the cam 53 has a sprocket 62 fixed thereto for rotation therewith. An idle shaft 66 rotatably mounted in the machine 10 has a pair of

similar sprockets

64 and 65 fixed thereto, and a shaft 67 connected to at least one of the rollers 15 has a pair of sprockets 68 and 69 fixed thereto. The electric motor 18 drives, through a brake mechanism 100, a sprocket 70, which is positively connected to the sprocket 69 by a continuous chain 72 such that the roller 15 is driven at a constant speed by the motor 18. The sprockets 68 and 65 are similarly connected by a chain 73, and the

sprockets

64 and 62 are interconnected by a chain 75. In this manner, the motor 18 drives not only the roller 15 at a constant speed, but also the cam 53. Furthermore, the positive interconnection thus provided by the chains assures the predetermined relationship between movement of the wire 13 and the abutment surface 27 even if for some reason the roller 15 and the cam 53 are not driven at the desired constant rate.

As just described, a continuous spring will be formed by the machine 10. It is, however, usually necessary to cut the continuous spring at predetermined intervals to form springs of proper length. To accomplish this is an accurate and efficient manner, a disc 80, as illustrated by H05. 1 and 5, is fixed to the shaft 54, the disc having a number of cam lobes 81 projecting radially therefrom for use in counting the number of coils formed. There are the same number of lobes 81 as there are constant radius portions 56, the same number of coils being formed for each full revolution of the cam 53 and the disc 80 (one large radius portion to each coil) as there are constant radius portions 56. A switch 83 is mounted adjacent the disc 80 in a position to be contacted and closed by each lobe 81 as it passes the switch 83 during rotation of the disc 80. Actuation of the switch 83 by each lobe 81 indicates to a control device 85 through a suitable circuit 86 that a single coil has been formed. The control device 85 counts the coils indicated in this manner and, when a predetermined number have been formed, signals a cutoff mechanism 90 illustrated by FIG. 1 to cut the wire intermediate the

surfaces

27 and 31.

The cutoff mechanism 90 includes shears 92 carried by a support 93 which is reciprocably mounted on a slide 94 for movement between a first position in which the cutting shears 92 are remote from the coil forming means and a second position in which the cutting shears 92 are positioned to cut the wire 13, the first position shown by solid lines and the second position by broken lines. The cutoff mechanism 90 also includes an actuating mechanism 95 for operating the shears 92 and a fluid actuator 96 for moving the support 93 along the slide 94 between its first and second positions. In operation, upon the formation of a predetermined number of coils, the control device 85 sequentially causes the actuator 96 to move the support 93 and the shears 92 from the first position into the second cutting position, the actuating mechanism 95 to operate the shears 92 to cut the wire, and the actuator 96 to return the support 93 and the shears 92 to the first position.

The control device 85 also actuates the brake mechanism 100 to stop the feed of the wire 13 and the reciprocation of the surface 27 during the cutoff operation. After the wire is cut, the brake 100 is released and the roller 15 again feeds the wire and the surface 27 is again reciprocated to form the coils of a new spring. On the other hand, the wire 13 may be cut while being continuously advanced through the machine. In either event, however, the cam lobes 81 on the disc 80 should be positioned to cause the wire 13 to be cut at the proper point, it being recognized that the wire 13 will in either case be advanced to a limited extent before the actual cutting occurs after the control device 85 signals the cutoff mechanism 96 that the predetermined number of coils have been formed.

While the arrangement of FIGS. 1-6 is the presently preferred form of the invention, it will be obvious to those skilled in the art that alternative arrangements can be utilized in the practice of the invention. For example, FIG. 7 illustrates an arrangement in which a pressure actuator 102 and valve means 103 are used in place of the cam 53 and its associated apparatus. More particularly, the pressure actuator 102 includes a cylinder 105 pivotally secured to the machine 10 at 106 and a piston 107 slidably mounted within the cylinder 105. A connecting rod 108 connects the piston 107 to a block 23 having an abutment surface 27 thereon for reciprocating the block 28 between a first position illustrated by solid lines and a second position illustrated by broken lines. The valve mechanism 103 selectively supplies pressurized fluid from a source 110 to a selected one of the

cylinder regions

112 and 113. When the actuating fluid is supplied to region 112, the piston 107 is moved to the right and the surface 27 is moved to its first position, and when the fluid is supplied to region 113, the piston 107 is moved to the left and the surface 27 is moved to its second position. Movement of the piston 107 must, of course, be coordinated with movement of the wire 13' by the roller This may be accomplished by mounting a disc 116 on the drive shaft 67' and locating suitable cam lobes 118 on the disc 116 for indicating formation of the various constant and variable radius portions of the coils. These cam lobes 118 actuate switches 120 to indicate to a control device 121 for the valve mechanism 103 the formation of each coil portion.

From the foregoing, it will be appreciated that the coil winding method and machine of this invention automatically produces coil springs of the nonuniform radii type in a rapid, efficient and accurate manner.

it will be understood that the invention is not limited to the specific details of the construction and arrangement of the illustrated embodiments since changes and modifications will be obvious to those skilled in the art. It is therefore intended to cover in the appended claims all such changes and modifications which may occur to those skilled in the art without departing from the true spirit and scope of the invention.

lclaim:

1. Coil springrwinding apparatus comprising:

means for supporting and guiding a wire along a longitudinal axis, said supporting and guiding means including a discharge portion,

forming means adjacent said discharge portion for bending a wire discharged from said discharge portion, said forming means including abutment means mounted for reciprocable movement between first and second end positions,

said abutment means in said first and second end positions extending transversely of said longitudinal axis in axiallyspaced relationship to said discharge portion such that a wire discharged from said discharge portion contacts said abutment means and is thereby deflected out of said longitudinal axis into a curved configuration,

the axial spacing between said abutment means and said discharge portion being greater in said second end position than in said first end position such that the radius of curvature of the wire portions fonned when said abutment means is in said second end position is greater than the radius of curvature of the wire portions formed when said abutment means is in said first end position,

said supporting and guiding means further including means for advancing a wire through said discharge portion into contact with said abutment means,

means for moving said abutment means alternately between said first and second end positions,

and control means operatively connected to and coordinating the operation of both said wire advancing means and said means for moving said abutment means such that relatively small movement of the wire occurs during movement in either direction of said abutment means between said end positions and relatively large movement of the wire occurs when said abutment means is in either of said endpositions,

whereby a coil spring wound on said coil spring winding apparatus includes a series of connected identical coils each having a portion of relatively small substantially constant radius formed when said abutment means is in said first end position, a portion of relatively large substantially constant radius formed when said abutment means is in said second end position, and portions of varying radius formed when said abutment means is being moved between said end positions, the constant radius portions being long relative to the varying radius portions.

2. Coil spring winding apparatus as defined by claim 1 in which said forming means further comprises stationary arbor means adjacent said discharge portion, said arbor means having a smoothly curved bending surface substantially tangent to said longitudinal axis adjacent said discharge portion and extending therefrom axially and laterally away from said discharge portion such that a wire deflected away from said longitudinal axis by said abutment means is bent around and accurately shaped by said curved bending surface.

3. Coil spring winding apparatus as defined by claim 1 in which said forming means further comprises:

pitch forming means positioned to longitudinally stretch the coils to provide a desired pitch, said pitch forming means being laterally offset from said longitudinal axis in a direction substantially normal to the plane in which the.

coils are formed,

and adjusting means for selectively varying the amount of lateral offset of said pitch forming means so as to thereby permit variation of the desired pitch.

4. Coil spring winding apparatus as defined by claim 1 further comprising automatic cutoff means for counting the number of coils formed and cutting the wire after a predetermined number of coils have been formed to form a spring of predetermined length.

5. Coil spring winding apparatus as. defined by claim 1 in which:

said wire advancing means includes at least one rotatably mounted roller positioned to engage and force a wire through said supporting and guiding means;

said means for moving said abutment means comprises:

a rotatably mounted cam having an even number of angularly spaced-apart constant radius peripheral portions thereon and an even number of variable radius transition peripheral portions interconnecting said constant radius portions, a first set of alternate ones of said constant radius portions having identical angular extents and identical radii and a second set of alternate ones of said constant radius portions having identical angular extents and identical radii different than the identical radii of said first set, the angular extents. of. each of said constant radius portions being long relative to the angular extents of said transition portions,

a cam follower biased into contact with the periphery of said cam,

and means connecting said cam follower and said abutment means for varying the position of said abutment means in accordance with the angular position of said cam;

said control means including means positively interconnecting said roller and said cam such that there is a direct relationship between longitudinal feed of a wire by said roller and movement of said abutment means.

6. Coil spring winding apparatus as defined by claim 5 in which the angular extent of each of the constant radius portions of said first set is approximately twice the angular extent of each of the constant radius portions of said second set.

7. Coil spring winding apparatus as defined by claim 6 in which the angular extent of each of the constant radius portions of said first and second sets is substantially greater than the angular extent of the transition portions.

0. Coil spring winding apparatus as'defined by claim 7 in which the ratio of the axial distance between said abutment means and said discharge portion in said second and first end positions, respectively, is 1.422.

9. Coil spring winding apparatus as defined by claim in which said forming means further comprises stationary arbor means about which a wire deflected away from said longitudinal axis by said abutment means may be bent and shaped, said stationary arbor means being positioned adjacent said discharge portion and being laterally offset from said longitudinal axis.

10. Coil spring winding apparatus as defined by claim 9 in which said forming means further comprises:

pitch forming means positioned to longitudinally stretch the coils to provide a desired pitch, said pitch forming means being laterally offset from said longitudinal axis along a direction substantially normal to the direction of lateral offset of said arbor means,

and adjusting means for selectively varying the amount of lateral offset of said pitch forming means so as to thereby pennit variation of the desired pitch.

1]. Coil spring winding apparatus as defined by claim 9 in which said abutment means includes a flat substantially smooth surface axially facing said discharge portion and said arbor means includes a smoothly curved bending surface substantially tangent to said longitudinal axis adjacent said discharge portion and extending therefrom axially and laterally away from said discharge portion, said forming means further comprising:

pitch forming means including a flat substantially smooth surface over which the coils are directed after being deflected by said flat abutment surface, said pitch forming surface being laterally offset from said longitudinal axis,

said smoothly curved bending surface being substantially perpendicular to said pitch forming surface and extending axially beyond said pitch forming surface toward said abutment surface,

and adjusting means for selectively varying the amount of lateral offset of said pitch forming surface so as to thereby permit variation of the desired pitch.

l2. Coil spring winding apparatus as defined by claim 5 further comprising:

a plurality of shafts,

bearing means supporting each of said shafts for rotation about its axis,

said roller and said cam fixed to respective ones of said shafts for rotation therewith,

a plurality of driven sprockets fixed to respective ones of said shafts,

drive means,

a driving sprocket rotatably driven by said drive means,

and chain means interconnecting said driving and said driven sprockets such that all of said shafts and consequently said roller and said cam rotate in unison at fixed ratios therebetween. l3. Coil spring winding apparatus as defined by claim 12 in which said means connecting said cam follower and said abutment means comprises:

a rotatably mounted axle, a first lever secured at a first end to said abutment means and at a second end to said axle at right angles thereto,

and a second lever secured at a first end to said cam follower and at a second end to said axle at right angles thereto, whereby movement of said cam follower by said rotating cam is converted into corresponding movement of said abutment means,

the elements of said connecting means being arranged such that the pressure of a wire contacting said abutment means biases said cam follower against the periphery of said cam and such that said abutment means is in said first end position when said cam follower is in contact with the larger radius peripheral portions of said cam and in said second end position when said cam follower is in contact with the smaller radius peripheral portions of said cam.

14. Coil spring winding apparatus as defined by claim 13 further comprising automatic cutoff means for counting the number of coils formed and cutting the wire after a predetermined number of coils have been formed to form a spring of predetermined length.

15. Coil spring winding apparatus as defined by claim R3 in which said abutment means includes a flat substantially smooth surface axially facing said discharge portion, said forming means further comprising:

stationary arbor means about which a wire deflected away from said longitudinal axis by said abutment surface may be bent and accurately shaped, said arbor means including a smoothly curved bending surface substantially tangent to said longitudinal axis adjacent said discharge portion and extending therefrom axially and laterally away from said discharge portion,

l6. Coil spring winding apparatus as defined by claim 15 further comprising:

cutting means,

means supporting and moving said cutting means between a first position remote from said forming means and a second position adjacent said forming means in which said cutting means is positioned to cut a wire discharged from said discharge portion,

means associated with said roller and said cam for indicating the formation of each coil,

and cutting means interconnecting said indicating means,

said cutting means, and said support means,

said cutting control means counting the number of coils formed as indicated by said indicating means and, upon the fonnation of a predetermined number of coils, sequentially causing said support means to move said cutting means from said first position to said second position, said cutting means to cut the wire adjacent said discharge portion, and said support means to return said cutting means to said first position from said second position.

17. Coil spring winding apparatus as defined by claim 16 further comprising brake means associated with said drive means for selectively stopping and permitting movement of said shafts and consequently said roller and said cam, said control also being connected to said brake means to cause said brake means to stop said shafts upon formation of said predetermined number of coils and to release said shafts after said cutting means has cut the wire.

18. Coil spring winding apparatus as defined by claim 16 in which said indicating means comprises:

a circular disc secured to the shaft supporting said cam for rotation with said cam,

a plurality of cam lobes secured to said disc and projecting radially therefrom, said lobes being peripherally equally spaced and there being one-half as many lobes as there are constant radius peripheral portions on said cam,

switch means adjacent said disc positioned for sequential actuation by said lobes during rotation of said disc,

and means interconnecting said switch means and said cutting control means such that momentary actuation of said switch means by each lobe indicates to said cutting control means the formation of a single coil.

19. Coil spring winding apparatus as defined by claim 1 in which:

said means for moving said abutment means comprises:

a double-acting-fluid pressure actuator including a cylinder and a piston slidably mounted within said cylinder for movement therein between first and second positions relative to said cylinder;

means securing one of said cylinder and said piston in a fixed position and means securing the other of said cylinder and said piston to said abutment means,

said abutment means being in said first end position when said cylinder and said piston are in said first relative position and in said second end position when said cylinder and said piston are in said second relative position,

and valve means for supplying pressurized fluid to said actuator for selectively moving said cylinder and said piston between said first and second relative positions.

20. Coil spring winding apparatus as defined by claim 19 in which said abutment means includes a flat substantially smooth surface axially facing said discharge portion, said forming means further comprising:

21. A method of winding coil springs comprising:

supplying wire to a bending location at a substantially constant feed rate,

bending the wire supplied to the bending location into a coil be sequentially bending the wire;

at a first fixed radius of curvature for a first predetermined period of time,

at a variable radius of curvature for a second predetermined period of time,

at a second fixed radius of curvature for a third predetermined period of time,

and at a variable radius of curvature for a fourth predetermined period of time,

said first and third periods of time being substantially longer than said second and fourth periods of time and the variable radii of curvature of the wire portions formed during said second and fourth periods of time varying gradually between said first and said second fixed radii of curvature and said second and said first fixed radii of curvature, respectively.

22. A method of winding coil springs as defined by claim 21 further comprising repeating said sequential bending steps a predetermined number of times and then cutting the wire so as to form a spring having a predetermined number of coils.

23. A method of winding coil springs as defined by claim 22 further comprising continuously stretching said coiled wire substantially normal to the plane in which the coils are formed to provide a predetermined constant pitch.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,576,120 Dated April 27, 1971 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 60, delete "and";

Column 3, line 3, after "surface 27" insert such Column 4, line 25, change "is" to in Column 8, line 37 after "cutting" insert control Column 10, line 10, change "be" to by Signed and sealed this 26th day of October 1 971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTISCHALK Attesting Officer Acting Commissioner of Patents

Claims

1. Coil spring winding apparatus comprising: means for supporting and guiding a wire along a longitudinal axis, said supporting and guiding means including a discharge portion, forming means adjacent said discharge portion for bending a wire discharged from said discharge portion, said forming means including abutment means mounted for reciprocable movement between first and second end positions, said abutment means in said first and second end positions extending transversely of said longitudinal axis in axiallyspaced relationship to said discharge portion such that a wire discharged from said discharge portion contacts said abutment means and is thereby deflected out of said longitudinal axis into a curved configuration, the axial spacing between said abutment means and said discharge portion being greater in said second end position than in said first end position such that the radius of curvature of the wire portions formed when said abutment means is in said second end position is greater than the radius of curvature of the wire portions formed when said abutment means is in said first end position, said supporting and guiding means further including means for advancing a wire through said discharge portion into contact with said abutment means, means for moving said abutment means alternately between said first and second end positions, and control means operatively connected to and coordinating the operation of both said wire advancing means and said means for moving said abutment means such that relatively small movement of the wire occurs during movement in either direction of said abutment means between said end positions and relatively large movement of the wire occurs when said abutment means is in either of said end positions, whereby a coil spring wound on said coil spring winding apparatus includes a series of connected identical coils each having a portion of relatively small substantially constant radius formed when said abutment means is in said first end position, a portion of relatively large substantially constant radius formed when said abutment means is in said second end position, and portions of varying radius formed when said abutment means is being moved between said end positions, the constant radius portions being long relative to the varying radius portions.

3. Coil spring winding apparatus as defined by claim 1 in which said forming means further comprises: pitch forming means positioned to longitudinally stretch the coils to provide a desired pitch, said pitch forming means being laterally offset from said longitudinal axis in a direction substantially normal to the plane in which the coils are formed, and Adjusting means for selectively varying the amount of lateral offset of said pitch forming means so as to thereby permit variation of the desired pitch.

5. Coil spring winding apparatus as defined by claim 1 in which: said wire advancing means includes at least one rotatably mounted roller positioned to engage and force a wire through said supporting and guiding means; said means for moving said abutment means comprises: a rotatably mounted cam having an even number of angularly spaced-apart constant radius peripheral portions thereon and an even number of variable radius transition peripheral portions interconnecting said constant radius portions, a first set of alternate ones of said constant radius portions having identical angular extents and identical radii and a second set of alternate ones of said constant radius portions having identical angular extents and identical radii different than the identical radii of said first set, the angular extents of each of said constant radius portions being long relative to the angular extents of said transition portions, a cam follower biased into contact with the periphery of said cam, and means connecting said cam follower and said abutment means for varying the position of said abutment means in accordance with the angular position of said cam; said control means including means positively interconnecting said roller and said cam such that there is a direct relationship between longitudinal feed of a wire by said roller and movement of said abutment means.

8. Coil spring winding apparatus as defined by claim 7 in which the ratio of the axial distance between said abutment means and said discharge portion in said second and first end positions, respectively, is 1.422.

9. Coil spring winding apparatus as defined by claim 5 in which said forming means further comprises stationary arbor means about which a wire deflected away from said longitudinal axis by said abutment means may be bent and shaped, said stationary arbor means being positioned adjacent said discharge portion and being laterally offset from said longitudinal axis.

10. Coil spring winding apparatus as defined by claim 9 in which said forming means further comprises: pitch forming means positioned to longitudinally stretch the coils to provide a desired pitch, said pitch forming means being laterally offset from said longitudinal axis along a direction substantially normal to the direction of lateral offset of said arbor means, and adjusting means for selectively varying the amount of lateral offset of said pitch forming means so as to thereby permit variation of the desired pitch.

11. Coil spring winding apparatus as defined by claim 9 in which said abutment means includes a flat substantially smooth surface axially facing said discharge portion and said arbor means includes a smoothly curved bending surface substantially tangent to said longitudinal axis adjacent said discharge portion and extending therefrom axially and laterally away from said discharge portion, said forming means further comprising: pitch forming means including a flat substantially smooth surface over which the coils are directed after being deflected by said flat abutment surface, said pitch forming surface bEing laterally offset from said longitudinal axis, said smoothly curved bending surface being substantially perpendicular to said pitch forming surface and extending axially beyond said pitch forming surface toward said abutment surface, and adjusting means for selectively varying the amount of lateral offset of said pitch forming surface so as to thereby permit variation of the desired pitch.

12. Coil spring winding apparatus as defined by claim 5 further comprising: a plurality of shafts, bearing means supporting each of said shafts for rotation about its axis, said roller and said cam fixed to respective ones of said shafts for rotation therewith, a plurality of driven sprockets fixed to respective ones of said shafts, drive means, a driving sprocket rotatably driven by said drive means, and chain means interconnecting said driving and said driven sprockets such that all of said shafts and consequently said roller and said cam rotate in unison at fixed ratios therebetween.

13. Coil spring winding apparatus as defined by claim 12 in which said means connecting said cam follower and said abutment means comprises: a rotatably mounted axle, a first lever secured at a first end to said abutment means and at a second end to said axle at right angles thereto, and a second lever secured at a first end to said cam follower and at a second end to said axle at right angles thereto, whereby movement of said cam follower by said rotating cam is converted into corresponding movement of said abutment means, the elements of said connecting means being arranged such that the pressure of a wire contacting said abutment means biases said cam follower against the periphery of said cam and such that said abutment means is in said first end position when said cam follower is in contact with the larger radius peripheral portions of said cam and in said second end position when said cam follower is in contact with the smaller radius peripheral portions of said cam.

15. Coil spring winding apparatus as defined by claim 13 in which said abutment means includes a flat substantially smooth surface axially facing said discharge portion, said forming means further comprising: stationary arbor means about which a wire deflected away from said longitudinal axis by said abutment surface may be bent and accurately shaped, said arbor means including a smoothly curved bending surface substantially tangent to said longitudinal axis adjacent said discharge portion and extending therefrom axially and laterally away from said discharge portion, pitch forming means including a flat substantially smooth surface over which the coils are directed after being deflected by said flat abutment surface, said pitch forming surface being laterally offset from said longitudinal axis, said smoothly curved bending surface being substantially perpendicular to said pitch forming surface and extending axially beyond said pitch forming surface toward said abutment surface, and adjusting means for selectively varying the amount of lateral offset of said pitch forming surface so as to thereby permit variation of the desired pitch.

16. Coil spring winding apparatus as defined by claim 15 further comprising: cutting means, means supporting and moving said cutting means between a first position remote from said forming means and a second position adjacent said forming means in which said cutting means is positioned to cut a wire discharged from said discharge portion, means associated with said roller and said cam for indicating the formation of each coil, and cutting means interconnecting said indicating means, said cutting means, and said support meaNs, said cutting control means counting the number of coils formed as indicated by said indicating means and, upon the formation of a predetermined number of coils, sequentially causing said support means to move said cutting means from said first position to said second position, said cutting means to cut the wire adjacent said discharge portion, and said support means to return said cutting means to said first position from said second position.

18. Coil spring winding apparatus as defined by claim 16 in which said indicating means comprises: a circular disc secured to the shaft supporting said cam for rotation with said cam, a plurality of cam lobes secured to said disc and projecting radially therefrom, said lobes being peripherally equally spaced and there being one-half as many lobes as there are constant radius peripheral portions on said cam, switch means adjacent said disc positioned for sequential actuation by said lobes during rotation of said disc, and means interconnecting said switch means and said cutting control means such that momentary actuation of said switch means by each lobe indicates to said cutting control means the formation of a single coil.

19. Coil spring winding apparatus as defined by claim 1 in which: said wire advancing means includes at least one rotatably mounted roller positioned to engage and force a wire through said supporting and guiding means; said means for moving said abutment means comprises: a double-acting fluid pressure actuator including a cylinder and a piston slidably mounted within said cylinder for movement therein between first and second positions relative to said cylinder; means securing one of said cylinder and said piston in a fixed position and means securing the other of said cylinder and said piston to said abutment means, said abutment means being in said first end position when said cylinder and said piston are in said first relative position and in said second end position when said cylinder and said piston are in said second relative position, and valve means for supplying pressurized fluid to said actuator for selectively moving said cylinder and said piston between said first and second relative positions.

20. Coil spring winding apparatus as defined by claim 19 in which said abutment means includes a flat substantially smooth surface axially facing said discharge portion, said forming means further comprising: stationary arbor means about which a wire deflected away from said longitudinal axis by said abutment surface may be bent and accurately shaped, said arbor means including a smoothly curved bending surface substantially tangent to said longitudinal axis adjacent said discharge portion and extending therefrom axially and laterally away from said discharge portion, pitch forming means including a flat substantially smooth surface over which the coils are directed after being deflected by said flat abutment surface, said pitch forming surface being laterally offset from said longitudinal axis, said smoothly curved bending surface being substantially perpendicular to said pitch forming surface and extending axially beyond said pitch forming surface toward said abutment surface, and adjusting means for selectively varying the amount of lateral offset of said pitch forming surface so as to thereby permit variation of the desired pitch.

21. A method of winding coil springs comprising: supplying wire to a bending location at a substantially constant feed rAte, bending the wire supplied to the bending location into a coil be sequentially bending the wire; at a first fixed radius of curvature for a first predetermined period of time, at a variable radius of curvature for a second predetermined period of time, at a second fixed radius of curvature for a third predetermined period of time, and at a variable radius of curvature for a fourth predetermined period of time, said first and third periods of time being substantially longer than said second and fourth periods of time and the variable radii of curvature of the wire portions formed during said second and fourth periods of time varying gradually between said first and said second fixed radii of curvature and said second and said first fixed radii of curvature, respectively.