US3915204A

US3915204A - Spring hook forming machine

Info

Publication number: US3915204A
Application number: US499521A
Authority: US
Inventors: Robert R Kaufman; Robert W Richter; Arnold H Richter
Original assignee: RICH IND Inc
Current assignee: RICH IND Inc
Priority date: 1974-08-22
Filing date: 1974-08-22
Publication date: 1975-10-28
Anticipated expiration: 1992-10-28

Abstract

An apparatus and process for forming hooks on the legs of a helical spring. A spring is delivered to gripper means which positions the spring to present one leg to a set of hook forming tools. A hook is formed and bending means operate to bend the spring leg parallel to the axis of the spring coil. Reversing means rotate the spring so that the same operation is performed on the second leg. Drive means and timing means are effective to sequentially operate each of the machine elements so that hooks are formed on both legs of a single spring before a new one is received.

Description

i United States Patent Kaufman et al.

1 Oct. 28, 1975 SPRING HOOK FORMING MACHINE [75] Inventors: Robert R. Kaufman, Melrose Park;

Robert W. Richter, Northlake; Arnold H. Richter, Long Grove, all of 111.

[73] Assignee: Rich Industries, Inc., Bensenville,

[22] Filed: Aug. 22, 1974 [21] Appl. No.: 499,521

[52] US. Cl.. 140/103 [51] Int. Cl. B21F 35/02 [58] Field of Search 140/71 R, 102, 103, 104

[56] References Cited UNITED STATES PATENTS 1,497,965 6/1924 Van Orman 140/103 2,456,222 12/1948 Stull 140/103 2,809,675 10/1957 Silko 140/103 3,040,784 6/1962 Ashley-Wing 140/103 3,069,024 12/1962 Penny 140/103 3,192,748 7/1965 Lange 140/103 3,194,282 7/1965 Bergevin et a1 140/103 3,672,410 6/1972 Scheckel 140/103 Primary Examiner-C. W. Lanham Assistant Examiner-E. M. Combs Attorney, Agent, or FirmKinzer, Plyer, Dorn & McEachran [57] ABSTRACT An apparatus and process for forming hooks on the legs of a helical spring. A spring is delivered to gripper means which positions the spring to present one leg to a set of book forming tools. A hook is formed and bending means operate to bend the spring leg parallel to the axis of the spring coil. Reversing means rotate the spring so that the same operation is performed on the second leg. Drive means and timing means are effective to sequentially operate each of the machine elements so that hooks are formed on both legs of a single spring before a new one is received. 7

7 Claims, 6 Drawing Figures /i4 w l l llll/i 2/3 I 39 /Z6 Z\ Aid] U.S. Patent Oct.28, 1975 Sheet2of3 3,915,204

US. Patent Oct. 28, 1975 Sheet 3 of3 3,915,204

SPRING HOOK FORMING MACHINE SUMMARY OF THE INVENTION The present invention relates to machines for producing helical springs and more particularly to machines for forming hooks on the legs of a helical spring.

A primary object of the invention is a machine, for automatically bending and forming hooks on the legs of a helical spring, in which hooks are formed on both legs sequentially by the same set of tools.

Another object is a spring hook forming machine which requires no more than a single unskilled worker for its operation.

Another object is a spring hook forming machine in which the amount of required tooling is minimized.

Another object is a spring hook forming machine which securely holds and rigidly positions a spring being formed so as to insure uniformity of the products of the machine.

Another object is a spring hook forming machine which produces a finished spring, with no additional forming operations required.

Another object is a spring hook forming machine in which the operating elements are quickly and expeditiously activated to maximize production.

Another object is a spring hook forming machine which is adjustable to accomodate production of springs of varying sizes.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated diagramatically in the following drawings, wherein:

FIG. 1 is a perspective view of the invention;

FIG. 2 is a fragmentary top plan view of portions of the invention including an enlarged fragmentary section view of a spring engaged by the hook forming tools;

FIG. 3 is a fragmentary side detail view of the gripper means including the mechanism for activating it;

FIG. 4 is a fragmentary rear plan view of the mechanism for raising and lowering the gripper head and reversing means;

FIG. 5 is a fragmentary side plan view of the bending means; and

FIG. 6 is a fragmentary top plan view of the bending means of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The spring hook forming machine of the present invention, as shown in FIG. 1, is constructed on a stationary base 10. A cam shaft 12 which extends along the periphery of the machine is the means for driving the various machine elements. The cam shaft, which is supported by a series of mounted bearings 14, is divided into four segments, shown best in FIG. 2, including a front segment 12a, right segment 12b, left segment 12c, and rear segment 12d. A hand wheel 16 is affixed to the end of the front segment for manual operation of the machine. Adjacent the hand wheel, a gear or sprocket 18 is rigidly secured on the cam shaft as a power takeoff from some external source such as an electric motor, not shown. A cam 20 is positioned on the front segment of the cam shaft to the right of the drive gear 18. This cam activates an electrical control 22, the purpose of which is explained below.

A bevel gear 24a, shown in FIG. 2, is secured along the front segment of the cam shaft to the right of cam 20. Bevel gear 24a is supported within a gear box 24 which also houses and supports a similar bevel gear 24b which is disposed normal to bevel gear 24a with which it is engaged. Bevel gear 24b is rigidly secured to the left segment of the cam shaft for transmitting rotation of the front segment thereto. A similar gear box 26 houses two bevel gears which are affixed to the front segment and right segment of the cam shaft respectively. A third gear box 28 rotatably interconnects the right segment and rear segment of the cam shaft.

A cam 30 is rigidly positioned along the front segment of the cam shaft to the right of bevel gear 24a. Cam 30 actuates the advancing mechanism of a load chute 32, shown best in FIG. 1. In the preferred embodiment, the load chute has an inclined base with a generally centrally located groove extending longitudinally from front to rear for supporting the coil portion of the springs to be operated upon, hereinafter referred to as work pieces. Vertical side members affixed to the inclined base support the leg portions of the work pieces so as to radially align the work pieces. A brace member 34 overlies the center groove and supports a hold down rod which extends downwardly parallel to and spaced from the center groove to prevent displacement of the coil part of the work pieces out of the center groove. The work pieces slide down the chute by gravity and are inten'nittently stopped and advanced by a pair of release fingers extending upwardly from the inclined base. Cam 30 raises a crank arm which rotates a shaft extending laterally across and below the load chute. A rocker block, which is rigidly attached to the shaft supports the release fingers. Therefore, as rotation of cam 30 raises and lowers one end of the crank arm, the shaft and rocker block are rotated back and forth thereby causing an opposite reciprocal movement of the release fingers normal to the surface of the inclined base. As the lower release finger is lowered, one spring is allowed to advance by gravity toward the machine while the upper pin holds back the remaining work pieces. As the rocker block is rotated, the upper finger is lowered, allowing all of the springs to advance one position with the bottom spring again positioned against the lower release finger.

The first cam 36 on the left segment of the cam shaft activates a carrier 38, as shown in FIG. 1. Cam 36 raises and lowers a cam follower 37 affixed to the end of a rack gear 40 which in turn, rotates a pinion gear mounted within a gear box 42. The pinion gear rotates the carrier shaft 44 on which carrier 38 is mounted. A load pin 46 protrudes from one end of the carrier 38 and is adapted to receive a work piece from the load chute when the carrier is rotated counterclockwise for the position shown in FIG. 1. When the load pin 46 is axially aligned with the work pieces in the load chute, the carrier is in its pickup position in which one of the work pieces may be allowed to slide onto the load pin. Subsequent clockwise rotation of the carrier approximately 225 places the carrier in its release position wherein the work piece and load pin are positioned generally vertical. Any suitable means may be provided for preventing the work piece from slipping off of the load pin in this position. In the preferred embodiment, a small felt spring loaded pad is urged against the work piece from an aperture in the outer face of the carrier 38. When the carrier is in its pickup position, the spring loaded pad is held away from the loading pin by means of a wedge mounted on the chute base. A spring 41 urges the cam followed of rack gear into engagement with cam 36 to ensure that it follows the pattern of cam 36 accurately.

A pair of gripper fingers 48 (FIG. 3) remove the work piece from the carrier 38 in its release position. The gripper fingers are rotatably mounted within a gripper head, as described below. In order for the gripper fingers to engage the work piece of the carrier, the gripper head must be elevated, by means described below, to raise the gripper fingers to a height as indicated at 50 in FIG. 3. In order to spread the gripper fingers apart for receipt of the work piece, a gripper activator mechanism indicated generally at 52 is provided. A cam 54, secured to the rear segment of the cam shaft, drives a cam follower 56, which is rotatably connected to a lever 58. The front end of lever 58 is pivotally mounted to a drive plate 60, the ends of which are connected by upper and

lower pivot arms

62 and 64 to a channel shaped stationary holding fixture 66, which is rigidly fastened to base 10. Vertical movement of the rear end of lever 58 is restricted by the holding fixture 66 so that as cam 54 raises lever 58, guide plate is pivoted forward and upward to a position indicated by the broken line 68 in FIG. 3. Note that a spring 70 urges the drive plate downward and thus rearward so that the drive plate cam assume the position indicated at 68 only when activated by the cam 54.

As shown in FIG. 3, the gripper fingers 48 are pivotally connected at 72 to form a pincerlike tool with handles 74 extending into a cylindrical slot 76 in a roller block 78. A pair of springs 80 are inserted in apertures on opposite sides of the roller block to bear against the outer sides of handles 74, thereby urging them together and closing the gripper fingers. Handles 74 may be spaced a small distance apart when the gripper fingers are in the closed position. The inner surfaces of a small end portion of handles 74 flare outwardly to form a widened slot 82 for receiving the tapered inner end of a spreader bar 84. The rear end of spreader bar 84 engages drive plate 60. As the drive plate is pivoted forward, the tapered end of spreader bar 84 is forced into the flared slot 82 between the handles of the gripper fingers thereby spreading the handles apart and opening the gripper fingers to load a work piece. When drive plate 60 is pivoted rearwardly by its own weight and the force of spring 70, springs 80 are effective to cause the flared edges of slot 82 to bear against the tapered inner end of spreader bar 84 thereby forcing it rearwardly and urging the gripper fingers to close upon the work piece.

The gripper head which rotatably supports the gripper fingers is referred to generally by reference character 86 in FIGS. 1-4. Gripper head 86 is guided and supported by a stationary fixture 88 having a slotted contact surface 90 along which the gripper head is free to slide vertically. Stationary fixture 88 is rigidly affixed to the base 10 of the machine. Gripper head 86 is constructed about a slider block 92 which has an integral slider arm 94 extending through the slotted contact plate 90 of the stationary fixture for a purpose described below. Two gripper support arms 96 extend downwardly and to the right from both sides of the slider block 92 to which they are affixed. Axially aligned holes extend through the gripper support arms adjacent their lower ends for receiving and rotatably supporting the gripper fingers. Gripper support arms 96 are spaced apart by a distance slightly greater than the width of rocker block 78 which is free to rotate between them. Spreader bar 84 extends through the rear gripper support arm.

To raise and lower the gripper head, a cam 98 is provided on the left segment of the cam shaft, as shown in FIGS. 2 and 4. Cam 98 bears against a cam follower 100 which is rotatably supported in the slot of a forked lever 102. The outer end of forked lever 102 pivots about a pin 104 which is horizontally supported between two side walls 106 which extend outwardly and downwardly from the stationary fixture 88 with their outer ends rigidly braced against the machine base 10. The inner ends of the forked lever 102 are pivotally connected to a slider pivot arm 108 which rotates about a pin 110 which extends horizontally between the forked ends of lever 102. The inner end of slider pivot arm 108 is in turn pivotally connected to slider arm 94 of the gripper head. Thus, as cam 98 is rotated, the forked lever 102 and slider pivot arm 108 cooperate to raise and lower the gripper head along plate 90 of stationary fixture 88.

The gripper head reciprocates vertically between a high load position and a low hook forming position. As shown in FIGS. 3 and 4, when the gripper head is in its load position, the gripper fingers are horizontally disposed in a position indicated at 50. The rear end of spreader bar 84 would then be positioned at 112. Similarly, when the gripper head has been lowered to its hook forming position, the gripper fingers would be axially aligned along line 114 with the rear end of spreader bar 84 positioned at 116.

To insure that the vertical travel of gripper head 86 accurately follows the pattern defined by the shape of cam 98, an air cylinder 118, as shown in FIG. 1, is mounted above forked lever 102, being supported on brace means spanning across the top surface of support walls 106. The piston of air cylinder 118 is connected by means of a shaft 120 to a pivotal connector 122 which is pivotally mounted on a pin 124 extending between the forked ends of lever 102. Air pressure is supplied to a control box 126 which houses a regulator valve for controlling the communication of air pressure to air cylinder 118. The regulator valve is electrically actuated by means of switch 22, referred to above, which is turn, is automatically operated by cam 20. Thus, switch 22 is effective to control the application of pressure exerted downwardly against forked lever 102 by air cylinder 118. Air cylinder 118 and control box 126 may be of any conventional type commonly used in machine construction.

To rotate the gripper fingers within the gripper head, another cam 128 is provided on the left segment of the cam shaft behind support walls 106, as shown in FIG. 2. A pivot arm 130 rotates about a pin 132 which extends rearwardly from the rear support wall 106 at a point above the axis of the cam shaft. The upper end of pivot arm 130 engages a swivel connecting member 134 which is secured to the outer end of an actuator rod 136. The inner end of rod 136, which extends generally horizontally inward, passes through support fixture 88 adjacent and behind gripper head 86. As shown in FIG. 4, gear plate 138 is screwed onto a threaded inner end of rod 136. To prevent gear plate 138 from rotating about rod 136, cylindrical slots 140 are cut into the outer face of plate 138 for receiving guide pins 142 which extend horizontally to the. left from support fixture 88. Thus, gear plate 138 is free to travel linearly in and out but is prevented from rotating. The inner surface of the lower half of gear plate 138 is tapered inwardly along generally half the length of the gear plate thereby defining at the upper edge of the tapered portion a lip 144. Aligned to theleft of gear plate 138, a gear block 146 is rigidly secured to the spreader'bar 84 along a section 148 of increased diameter. The gripper means of the present invention are so constructed that rotation of gear block 146 causes the spreader bar 84, rocker block 78-and gripper fingers 48 to rotate therewith. Gear plate 138 and gear block 146 cooperate to rotate the gripper fingers as the gripper head is raised from its hook forming position indicated at 116 in FIG. 4. A lobe on cam 128 may be rotated into engagement with the cam follower of rocker arm 130. The lower end of the rocker arm is thus forced outwardly which in turn forces the actuator rod 136 to the left. This motionof rod 136 is effective to position the inner edge of gear plate 138 vertically above a portion of gear block 146. Upward movement of the gripper head forces one of the teeth 149 of gear block 146 into engagement with the lower edge 150 of gear plate 138. Further upward movement of the gripper head forces the gear block 146 to rotate 90 to a position shown in FIG. 4. Continued ascent of the gripper head will force the adjacent tooth of gear block 146 into engagement with lip 144 of gear plate 138 thereby rotating gear block 146, and thus the gripper fingers, another 90. Upon descent of the gripper head, cam 128 allows gear plate 138 to be retracted by a return spring toward support fixture 88,0ut of the path of the descending gear block 146.

When the gripper head has been lowered into its hook forming position with a work piece held by the gripper fingers, additional brace means rigidly secure the work piece in a uniform predetermined position for the forming operations. The card 152 on the right segment of the cam shaft bears against a slide 154 to which a clamp tool 156 is affixed (FIGS. 1 and 2). Slide 154 is free to travel right to left in a longitudinal groove in its base 158. A cam follower 160 on the outer end of slide 154 is urged into engagement with cam 152 by a spring 162. Form tool 156 affixed to the inner end of slide 154 comprises a lower horizontal plate 164 which underlies generally half of the work piece and an upper curved wedge 166 which is forced between two of the lower coils of a work piece when slide 154 is forced inward by cam 152. A solid non-moving backup 167 protrudes upwardly from the machine base along the left side of the work piece to laterally position the work piece and to resist the force of brace "means 156 which otherwise would deform the work piece. Although slide base 158 is prevented from moving right to left, another slide is effective to move base 158 laterally front to rear for a purpose described below. Slide 168 is activated by cam 170 on the rear segment of the cam shaft. Slide 168 has a central elevated portion 171 to which a cam follower is attached and a wider base portion 172 which is slidably constrained between sleeve members 174 which are rigidly secured to the machine base 10. Slide bases 172 and 158 are secured together to form an integral unit so that slide 168 is effective to determine the lateral position of slide 154. Slide 168 is urged toward the back of the machine into engagement with cam 170 by a spring 176.

When a work piece is held and braced in its hook forming position, its lower leg extends laterally to the left from the front side of the coil. To form a hook on the end of this leg of the work piece, a series of hook forming tools are provided. First, a cam 178 (FIG. 1), on the front segment of the cam shaft is effective to operate a standard slide 180 to which an inwardly protruding plate 182 is affixed. A downwardly extending pin 184 is rigidly attached to plate l82 adjacent its inner edge. Slide 180 is mounted at such a height that in its innermost or hook forming position, plate 182 overlies the spring leg and pin 184 abuts against the same. Another cam 186 on the rear segment of the cam shaft is effective to operate a slide 188 to which a first hook forming tool 190 is affixed. As shown in an enlarged view in FIG. 2, tool 190 is a rigid horizontal plate, with an integral extension 192, the right side of which is curved along a radius slightly greater than that of pin 184. With slide 188 in its fully inserted or hook forming position, the end of the spring leg is compressed between tool 190 and pin 184 so that the end portion of thespring leg is disposed generally normal to the remainder of the leg. A second hook forming tool 194 is affixed to the end of a slide 196 which is activated by a cam 198 on the left segment of the cam shaft. The right end of the back face of tool 194 is slightly curved along a radius slightly greater than that of pin 184. Tool 194 is inserted from left to right along a line slightly in front of pin 184 so that the end portion of the spring leg is compressed between the curved portion of tool 194 and the front surface of pin 184. A stop member 195 is rigidly anchored to the machine base and projects upwardly at a position generally in front of pin 184 in its fully inserted position. The back face of stop member 195 is inclined at generally the same angle as the right front corner of tool 194. As a result, in its fully inserted position, tool 194 abuts against stop member 182 along the inclined plane so that tool 194 is forced against the front face on pin 184.

.Slide 188 of the first hook forming tool 190 is urged by a spring 200 (FIG. 1) into engagement with cam 186. Similar springs, not shown, urge slides 196 and 180 of the second hook forming tool and pin into engagement with their

respective cams

198 and 178.

To bend the spring leg downward to a position parallel to the axis of the work piece, a grooved pin 202 is inserted over the spring leg adjacent the coil and forced downwardly against the spring leg thereby bending the same. As shown in FIGS. 5 and 6, grooved pin 202 protrudes toward the spring leg from a pivot member 204. Grooved pin 202 is fitted into a cylindrical slot in pivot member 204 and secured therein by a set screw 206. Pivot member 204 is pivotally mounted on a shaft 208 which is secured to the end of a slide 210 normal to its direction of travelpln FIGS. 1 and 6, it can be seen that a spring 212 urges pivot member 204 forward or away from the spring leg. Another slide 214 which is activated by a cam 216 on the front segment of the cam shaft, is effective to force pivot member 204 toward the work piece against the urging of spring 212 to a position where grooved pin 202 overlies the spring leg as shown in FIG. 6. With cammed pin 202 so positioned,

slide 210 may be forced outwardly by cam 218 on the right segment on the cam shaft thereby forcing a protuberance 220 on the top of pivot member 204 against a stationary stop member 222. Pivot member 204 is thus forced to rotate beneath stop member 222 with the result that grooved pin 202 is forced downwardly against the spring leg bending it to a position indicated at 22-1 in FIG. 5.

Note that slide 210 extends below the right segment of the cam shaft within a base 226. A block 228 is secured to the outer end of slide 210 and has a cam follower 230 supported thereon. A spring 232 urges slide 210 inward so that pivot member 204 may assume the position of FIGS. and 6. When slide 210 is in its inner position, spring 212 is also effective to lift the free end of pivot member 204 as well as pull it forward away from the work piece.

The use, operation and function of the invention are as follows:

All of the various machine elements described above are activated by the various cams secured to the cam shaft 12. The sequence and duration of the machine elements is thus determined by the configuration of the various cams. In the preferred embodiment shown in FIG. 1, each 360 rotation of the cam shaft causes the machine to complete one full cycle. In each cycle, one work piece is received, each leg of the work piece is hooked and bent sequentially and the finished work piece is released.

To begin with, cam actuates the advancing mechanism of load chute 32, thereby depressing the lower release finger and allowing one work piece to slide onto load pin 46 of carrier 38. After releasing one work piece, further rotation of cam 30 will lower the upper release finger and raise the lower release finger thereby advancing one work piece into position for the next cycle. Rotation of cam 36 then raises rack gear 40 which in turn rotates the carrier from its pickup position to its release position. Cam 98 then raises forked lever 102 which in turn raises the gripper head 86 so that gripper fingers 48 assume the position indicated at 50 in FIG. 3. As the gripper head is raised, cam 54 activates gripper mechanism 52 which pushes spreader bar 84 between gripper handles 74, thereby opening the gripper fingers. With gripper head 86 raised to its load position, further rotation of cam 54 allows drive plate to be retracted by the force of spring 70, with the result that springs in rocker block 78 are effective to close the gripper fingers. With a work piece secured in the gripper fingers, a steep edge on cam 98 is rotated past cam follower 100 of forked lever 102 with the result that the gripper head 86 immediately falls to its hook forming position. Simultaneously, cam 20 activates switch 22 which is effective to cause air cylinder 118 to exert a downward force or forked lever 102 so that it will accurately follow the pattern of cam 98 and not bounce due to the impact of reaching the hook forming position. The air pressure from cylinder 118 is released as cam 20 continues to rotate.

With the gripper head in its hook forming position, cam moves slide 154 forward through the action of slide 168. Cam 152 then forces slide 154 to the left engaging brace means 156 against the work piece. At this point, cam 178 pushes slide 180 which positions pin 184 in the hook forming position. Cam 186 forces slide 188 forward which causes the first hook forming tool 190 to bend the end of the spring leg partially around pin 184. Cam 198 then forces slide 196 inward thereby completing the hook with tool 194. Further rotation of the cam shaft allows the

hokk forming tools

190 and 194 to be retracted slightly by the action of their return springs and cam 216 forces slide 214 rearward so as to position grooved pin 202 above the spring leg. Cam 218 then forces slide 210 outward causing pivot member 204 to swing downward under stop member 222, thereby bending the spring leg to a position indicated at 224 in FIG. 5. As the spring leg is bent, the bottom of the work piece coil is still rigidly braced by brace 156. With one leg hooked and bent,

hook forming tools

190 and 194 and pin 184 are retracted to their outer positions; grooved pin 202 is pulled forward above and away from the work piece; and slide 154 is retracted to the right by spring 162 and rearwards by spring 176. The purpose of slide 168, which retracts brace slide 154 rearwardly when not in use, is to provide clearance for the legs of the work piece to rotate.

Cam 98 again raises forked lever 102 which causes the gripper head to rise to its load position. Simultaneously, cam 128 forces actuator rod 136 to the right causing gear plate 138 to engage the rising gear block 146. As teeth on gear block 146 engage the lower edge 150 and lip 144 of gear plate 138, gear block 146 as well as the gripper fingers are rotated generally 180. Cam 128 allows gear plate 138 to be retracted as gripper head 86 again falls to its hook forming position with the aid of air pressure from cylinder 118.

The second leg is hooked and bent similarly to the first leg. Upon completion of the bending by grooved pin 202 however, gripper fingers 148 are released as well as the brace means 156 so that the completed work piece may fall freely through an opening in machine base 10 onto a finished parts chute or bin. The operation is then complete allowing for another cycle.

More simply, in each cycle of the machine of the present invention, a work piece is received by the gripper fingers and rigidly held therein; hook forming tools and bending means hook and bend one leg of the work piece; and the gripper fingers rotate the work piece so that the other leg is hooked and bent by the same hook forming tools and bending means; after which the com pleted work piece is released from the gripper fingers.

With the present invention, the production of finished springs is accomplsihed rapidly and automatically with a minimum amount of tooling. Because the gripper fingers may be rotated to reverse the positions of the spring legs, both legs may be hooked and formed by a single set of tools. Production speed is easily regulated since all of the various machine elements are driven by a single cam shaft. The timing of the machine elements is thus predetermined and fixed by the configuration of the various cams and no further adjustments are necessary to accomodate different operating speeds. in addition, the air cylinder above the gripper head and return springs on each of the slides and mechanisms equip the machine of the present invention for successful high speed operation. The constant attention of an operator during each cycle of the machine and coordination between the operator and machine are not required for the present invention since severeal work pieces may be stacked on the load chute at one time and the advancing mechanism is effective to automatically feed one work piece per cycle. Finally, while the automatic handling of the work pieces by the grip per fingers and brace means assures the uniformity of springs produced during a single production run. the

cam shaft and machine base respectively so as to accomodate the production of various sizes of springs.

positions of the cams and slides are adjustable on the Whereas the preferred form of the invention has been described herein, it should be realized that there may be many modifications, substitutions, and alterations thereto.

We claim:

1. A machine for forming hooks on the legs of a helical spring comprising:

a. a stationary base;

b. gripper means capable of receiving, holding and releasing a helical spring;

0. hook forming tools effective to form a hook on the end of one leg of a spring held by the gripper means;

d. bending means effective to bend the leg to a spring, held by the gripper means, from its initial position generally normal to the axis of a helical spring to a position generally parallel to said axis;

e. reversing means effective to rotate a helical spring held by the gripper means thereby reversing the positions of the spring legs and presenting the second leg of the spring to the hook forming tools and bending means;

f. drive means effective to activate elements b) through e); and,

g. timing means to control the sequence and duration of the activation of elements b) through 6) so that both legs of a single spring are hooked and bent before another spring is received by the gripper means.

2. The structure of claim 1 further characterized in that said drive means and timing means comprise a cam shaft and series of cams.

3. The structure of claim 2 further characterized in that said hook forming tools comprise:

a center pin about which a hook is formed, and

a punch, mounted on a slide activated by the cam shaft, effective to bend a spring leg around said pin.

4. The structure of claim 3 further characterized in that said bending means comprises a pin adapted to overlie and engage the leg of a spring at a point adjacent the spring coil, and

slider means activated by said cam shaft and effective to force the pin against the spring leg thereby bending the same.

5. The structure of claim 4 further characterized in that said gripper means comprises a pair of gripper fingers operable to be closed together in a scissors-type motion thereby gripping the coil of a spring inserted between them.

6. The structure of claim 5 further characterized by and including a gripper head which supports at least portions of said gripper means and reversing means, and which is effective when activated by the cam shaft to reciprocate the gripper means between a load position, in which a spring is received, and a hook forming position, said reciprocation of the gripper head being effective to operate the reversing means in conjunction with the drive means.

7. The structure of claim 6 further characterized by and including a load chute for holding a plurality of helical springs and carrier means effective to receive a spring from said load chute and deliver said spring for receipt by the grippaer X26828.

Claims

1. A machine for forming hooks on the legs of a helical spring comprising: a. a stationary base; b. gripper means capable of receiving, holding and releasing a helical spring; c. hook forming tools effective to form a hook on the end of one leg of a spring held by the gripper means; d. bending means effective to bend the leg to a spring, held by the gripper means, from its initial position generally normal to the axis of a helical spring to a position generally parallel to said axis; e. reversing means effective to rotate a helical spring held by the gripper means thereby reversing the positions of the spring legs and presenting the second leg of the spring to the hook forming tools and bending means; f. drive means effective to activate elements b) through e); and, g. timing means to control the sequence and duration of the activation of elements b) through e) so that both legs of a single spring are hooked and bent before another spring is received by the gripper means.

3. The structure of claim 2 further characterized in that said hook forming tools comprise: a center pin about which a hook is formed, and a punch, mounted on a slide activated by the cam shaft, effective to bend a spring leg around said pin.

4. The structure of claim 3 further characterized in that said bending means comprises a pin adapted to overlie and engage the leg of a spring at a point adjacent the spring coil, and slider means activated by said cam shaft and effective to force the pin against the spring leg thereby bending the same.

7. The structure of claim 6 further characterized by and including a load chute for holding a plurality of helical springs and carrier means effective to receive a spring from said loaD chute and deliver said spring for receipt by the gripper means.