EP0037415B1

EP0037415B1 - Spring coiling machine with improved feed roll drive means

Info

Publication number: EP0037415B1
Application number: EP80902097A
Authority: EP
Inventors: Erman V. Cavagnero; Nicholas J. Marracino
Original assignee: Torin Corp
Current assignee: Madison Management Group Inc
Priority date: 1979-10-09
Filing date: 1980-10-02
Publication date: 1984-04-18
Also published as: JPH037456B2; IT8068560A0; FR2467028B1; CA1144041A; EP0037415A4; ATE7117T1; MX154096A; EP0037415A1; JPS56501395A; WO1981000974A1; DE3067556D1; FR2467028A1

Abstract

A cyclically operable spring coiling machine has a pair of feed rolls (12, 14 and 16, 18) for intermittently advancing wire to a coiling station (20). A coiling arbor (32) and tool (34) at the coiling station (20) cooperatively form leading end portions of the wire to a coil spring configuration and a cutoff tool (36) severs the coiled leading end portions of the wire to provide individual coil springs. Feed roll drive means includes drive gears (80, 82, 84, 86), a unidirectional clutch, and a feed roll cam (60) with an associated follower (64) and lever (66) driving a reciprocable rack (88) associated with a feed roll drive gear (74). Low inertia reciprocating and oscillating elements are provided for accurate and high speed machine operation.

Description

TECHNICAL FIELD

This invention relates to spring coiling machines and, more particularly to a cyclically operable spring coiling machine having a coiling station, at least one pair of oppositely rotatable feed rolls for intermittently advancing wire longitudinally to the coiling station, a relatively fixed wire coiling arbor at the coiling station, at least one relatively fixed coiling tool at the coiling station arranged to engage the longitudinally advancing wire to obstruct the linear movement thereof whereby progressively to bend the same about the coiling arbor and impart a coiling stress thereto resulting in the formation of a coil spring configuration at a leading end portion thereof, a cut-off tool at said coiling station operable successively to sever coiled leading end portions of the wire whereby to provide individual coil springs, feed roll drive gear means including unidirectional drive means and an operatively associated input drive gear, the unidirectional drive means causing said feed rolls to rotate oppositely and in wire feeding direction on rotation of said input gear in a drive direction and rendering said feed rolls inoperative on rotation of said input gear in an opposite and return direction, power operated means for driving said gear means and feed rolls including a continuously rotatable drive shaft.

BACKGROUND ART

Prior art spring coiling machines fall into two general categories - segment and clutch-type machines - with reference to the type of the feed roll drive mechanism incorporated in the machine. Segment-type coilers are the more common and include a large oscillatory gear segment driving a feed roll gear train with a unidirectional clutch for intermittent longitudinal wire advancement to a coiling station. While coiling machines of this type are characterised by a high degree of accuracy and dependability in use, they are somewhat limited with regard to high speed production. A relatively heavy and high inertia element such as a large gear segment has inherent limitations in increasing the speed of operation of the machine. In a typical high volume production operation automotive valve springs are produced on segment-type coiling machines manufactured by Torin Corporation of Torrington, Connecticut, at a production rate of approximately 80 springs per minute.
In an attempt to improve the production rates of segment-type spring coiling machines, a Wafios machine employs a larger number of feed rolls than the conventional segment coiler but the rolls are of smaller size to reduce inertia and a light-weight aluminium alloy segment is used in place of the conventional gray iron and steel segment. This results in some reduction of inertia forces and in a high volume valve spring operation as mentioned above the Wafios machine has achieved production rates of approximately 100 to 110 springs per minute.
Clutch-type spring coilers employ a clutch in place of the segment for driving the feed rolls and are particularly well adapted to applications where long wire feeds or even continuous wire feeding is required. Clutch-type machines may also employ a continuous wire feed with a flying-cutoff device for severing the individual springs. While relatively high rates of production can be achieved, the accuracy of clutch machines cannot match the segment-type spring coiling machines and it is often necessary to reduce machine speed in order to obtain the necessary accuracy and dependability in operation. Reference is made to U.S. Patent Specification 2,119,002, French Patent Specification 1,315,882 and Canadian Patent Specification 672,315.
It is the general object of the present invention to provide a spring coiling machine having cam driven feed rolls and which exhibits a high degree of accuracy and dependability in use and an accompanying substantial improvement in the speed of operation over that of segment-type spring coiling machines.

DISCLOSURE OF INVENTION

In fulfillment of the foregoing object, a cyclically operable spring coiling machine is provided with at least one feed roll cam mounted on said drive shaft for continuous rotation therewith, cam actuated means including a cam follower an an operatively associated oscillable cam lever having an output end portion movable in one and an opposite direction respectively for drive and return rotation of said input gear in said feed roll gear means, a drive and connecting device between said output end portion of said oscillable cam lever and said input gear for rotating the latter in said drive and return directions respectively on movement of said cam lever end portion in said one and opposite directions, and wire feed length adjustment means operatively associated with said oscillable cam lever and connecting means and serving to adjust the degree of input gear drive rotation relative to cam follower movement.
With the foregoing arrangement a substantial reduction of inertial forces is achieved in reciprocating and oscillating elements and a substantial improvement in machine operating speed realised. Further, the wire feeding portion of a machine cycle in a segment machine is limited to about 230° or less depending on the length of wire being fed. With a cam drive it is possible to achieve approximately a 270° feed portion of a cycle with a 90° return portion for all wire lengths. The short return portion of the cycle is possible due to the low inertia characteristics of reciprocating and oscillating elements and the absence of any requirement for return of a relatively heavy segment. As will be apparent, the ability to employ a larger portion of each cycle of machine operation in the wire feeding operation reduces wire velocity for a given wire length and a corresponding reduction occurs in inertial and coiling load, the latter referring to reactive forces on the feed rolls resulting from the coiling operation as well as loading on the coiling tool, etc. The approximate 15% increase in the feed portion of the cycle results in a considerable reduction in friction at the coiling tool. Still further, it is possible to design highly desirable acceleration and deceleration characteristics into a cam. This is quite difficult if not impossible to achieve with a conventional segment drive where adjustments are limited to the relative positioning of a pivot point and a bull gear which drives the segment.
With the foregoing advantages of the cam drive, the spring coiling machine of the present invention is capable of producing 130 springs per minute in the above mentioned high volume valve spring operation. Thus, approximately a 60% improvement is achieved in the rate of production over that of a conventional segment drive machine and yet the accuracy and the dependability of a segment drive machine is equaled if not exceeded.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a somewhat schematic illustration of a spring coiling machine viewed from the front and including the improved feed roll cam drive of the present invention.
Fig. 2 is an enlarged and somewhat schematic view taken from the rear of the machine and illustrating the cam drive means of the present invention in a first form.
Fig. 3 is a further enlarged and somewhat schematic view similar to Fig. 2 illustrating the first form of the cam drive means.
Fig. 4 is a schematic view similar to Fig. 2 but illustrating a second embodiment of the cam drive means of the invention.
Fig. 5 is an enlarged vertical sectional view taken through a cam lever and wire feed length adjustment means forming a third embodiment of the invention.
Fig. 6 is a right-hand side view of the cam lever and adjustment means of Fig. 5.
Fig. 7 is a generally horizontal sectional view taken generally as indicated by the line 7-7 in Fig. 5.

BEST MODE OF CARRYING OUT THE INVENTION

Referring particularly to Fig. 1, it will be observed that a spring coiling machine indicated generally at 10 has first and second pairs of oppositely rotatable feed rolls 12, 14 and 16, 18 for advancing wire longitudinally to a coiling station indicated generally at 20. In Fig. 1 the upper feed rolls 12, 16 rotate in a clockwise direction and the lower rolls 14, 18 in a counterclockwise direction to feed wire 22 leftwardly through guides 24, 26, 28 for the formation of the wire into a coil spring configuration 30 at its leading end portion. The leading end portions of the wire 22 are coiled about a coiling arbor 32 at the coiling station 20, the arbor cooperating with a coiling tool 34 at the station in the form of a coiling roll. The coiling arbor 32 and tool 34 are fixed at the coiling station relative to the wire so that longitudinally advancing wire engages the tool 34 and is obstructed in its linear movement thereby, the wire thus being progressively bent about the arbor 32 with a coiling stress imparted thereto resulting in the formation of the leading end coil spring configuration.
When the leading end portion of wire 22 has been bent to a coil spring configuration above the arbor 32 it is severed from the remaining portion of the wire 22 by means of a cutoff tool as indicated at 36, individual coil springs thus being formed. Element 38 at the coiling station 20 may take the form of a second cutoff tool or a pitch tool engageable with the wire during coiling about the arbor 32 progressively to pitch the same as required for the coil spring to be formed.
As thus far described and illustrated schematically, the spring coiling machine 10 is or may be conventional and for further illustration and description of such a machine including operating means for elements such as the cutoff tool 36 and pitch tool 38 reference may be had to Bergevin and Nigro patent no. 2,119,002 for SPRING COILING MACHINE, dated May 3, 1938. The machine shown and described in the patent, however, is of the segment drive type mentioned above and while highly accurate and dependable in operation is limited as to its rate of spring production.
The spring coiling machine of the present invention is cyclically operable as in the case of the segment coiler of the aforementioned patent and operates to intermittently advance wire longitudinally leftwardly to the coiling station 20. As indicated, the feed roll drive means in the machine of the present invention is of the cam type rather than the segment type with resulting operational and economic advantages. In Fig. 1, a drive motor and speed reducer 40 are illustrated at a right-hand portion of the machine, and in Fig. 2 an output pulley or sprocket 42 drives a pulley or sprocket 44 via a pulley or sprocket 46 associated therewith. The pulley or sprocket 44 has a coaxial gear 48 rotatable therewith to drive a gear 50 in the counterclockwise direction as illustrated in Fig. 2. The gear 50 has a coaxial gear 52 in turn driving a gear 54 in a clockwise direction and serving to rotate the gear 56 on a shaft 58 in a counterclockwise direction. Thus, the shaft 58 is power driven for continuous rotation and may hereafter be referred to as a power driven cam shaft, the shaft also carrying a cam 60 which is a principal element in a feed roll drive means of the present invention.
The cam 60 includes a track 62 partially illustrated in Fig. 3 and which has an associated follower 64 at a lower end portion of a cam lever 66. The cam lever 66 is oscillable in Fig. 3 about a pivot shaft 68 and carries at an upper or free end portion thereof a slide 70. The slide 70 in turn operates a drive and connecting device 72 for pinion gear 74, an input gear in a feed roll drive means. As will be described hereinbelow, the slide also forms a part of a wire feed length adjustment means operatively associated with the cam lever 66 and the drive and connecting device 72 and which may be a part of either or both of said elements.
Returning now to Fig. 2, it will be observed that the input or pinion gear 74 is mounted on a shaft 76 and also drives a larger gear 78 for driving feed roll gears 80, 82, 84 and 86. A unidirectional or index clutch is also a part of the feed roll drive gear means and may be mounted on the shaft 76 between the pinion gear 74 and the larger gear 78. Thus, the feed rolls may be operated to rotate in a drive or wire feeding direction and to remain stationary in a return direction of elements including the gear 74, the drive and connecting device 72, the cam lever 66 and follower 64. As illustrated in Fig. 2, gears 80, 82 respectively drive feed rolls 14, 12 and gears 84, 86 respectively drive feed rolls 16, 18. The drive or feed direction of gear and roll rotation is indicated by small arrows in Figs. 1 and 2.
Reverting to Fig. 3, the drive and connecting device 72 preferably comprises a rack assembly including a rack gear 88 on a reciprocable link 90 pivotally connected at a right-hand end portion 92 to the slide 70. A housing 94 mounted on the hub of gear 74 is rotatable through at least a limited arc and slidably receives the link and/or rack gear 88. Thus, the action of the link 90 and rack gear 88 is not precisely linear but tends to the oscillatory with the link slidable in the swingable housing 94 and with ball or roller bearings 96 provided in the housing for free sliding action.
As will be apparent, cam induced oscillation of the follower 64 relative to the cam or drive shaft 58 will result in oscillatory movement of the lever 66 about its pivot shaft 68, reciprocable or slightly oscillatory movement of the link 90 and in rotation of the pinion or input gear 74 in one and an opposite direction by the rack gear 88. The small arrows in Fig. 2 indicate such movement in a drive or wire feeding direction with a return or inoperative movement of course occurring in an opposite direction. As mentioned above, the rotation of the cam 60 may be continuous with reciprocating and/or oscillating movement occurring between the cam and the feed rolls 12-18, the unidirectional clutch on the shaft 76 serving to terminate feed roll rotation at the end of a wire advancing or feeding portion of the machine cycle. As mentioned, a portion of the cycle as high as 270° can be employed for feeding wire with the cam driven feed roll arrangement of the present invention. As illustrated, the machine is designed for a limited range of wire feed lengths particularly well suited to the automotive valve spring operation mentioned above, that is, a 25,4 to 101,6 cm (10 to 40 inch) variation or adjustment in wire feed.
The wire feed length adjustment means of the invention includes the slide 70 as mentioned and a means for moving the slide in one and an opposite direction along the length of the lever 66 and for fixing the slide in a desired position of adjustment. As illustrated in Fig. 3, a lead screw 98 is associated with the slide 70 and has an end portion thereof secured in the body of the lever 66 at 100. Rotation of the lead screw serves to adjust the position of the slide 70 along the lever 66 and a fixing or binding screw 102 serves to secure the slide in adjusted position along the lever. Thus, a maximum throw is provided for the oscillable lever 66 with the slide 70 positioned at its extreme outward limit as illustrated. As the slide is adjusted inwardly or downwardly along the length of the cam lever lesser wire feed lengths are provided for as desired.
While the machine illustrated is limited as stated with regard to the range of wire feed, it is to be understood that various other ranges of wire feed length can be readily provided for by substituting cams of suitable design for the cam 60. Further, and with regard to inertia reduction and high speed machine operation, it should be observed that each of the reciprocating and/or oscillating elements is constructed and arranged to provide for minimum weight and internal conditions. The cam 60 and/or substitute cams has an inherent capability for adjustment and selection of desired acceleration and deceleration characteristics of the feed rolls. Presently under consideration are a cycloidal acceleration characteristic for a wire feeding operation of the feed rolls. The return movement of the cam may be a second or third harmonic motion. Also under consideration are third harmonic foward and return motions as well as a modified sine characteristic for acceleration.
In Fig. 4, a second form of the feed roll drive means of the present invention is illustrated and includes a linearly reciprocable rack 88a driving a pinion gear 74a. The rack 88a is driven by a connecting link 90a having a pivotal connection therewith at 104. Cam lever 60a has a pivot shaft at 106 and a follower at 64a cooperating with an externally configured cam 60a. The construction and arrangement of the spring coiling machine may be otherwise identical with that illustrated and described above.
Figs. 5-7 illustrate a wire feed length adjustment means capable of running operation i.e., adjustable while the spring coiling machine is in operation. A cam lever 66b is substantially identical with the lever 66 and has an associated slide 70b moved longitudinally of the lever by means of a lead screw 98b. The lead screw 98b, at a lower or inner end portion is power operated from small motor 108 which may comprise a motor of the air or hydraulic type e.g., a Gardner air motor or a Lamina Company hydraulic motor. A lock-up or position fixing device for the slide 70b may take the form of a small FAB Co. pancake cylinder, air or hydraulic, indicated at 110. The small lock-up cylinder 110 is mounted on bracket 112 secured as by suitable screws 114, 114 to the slide 70b and having an output number 116 frictionally engageable with a rear portion 118 of the cam lever. As will be apparent, the member 116 is withdrawn or at least released on the member 118 during longitudinal adjustment of the slide 70b relative to the cam lever 66b, the motor 108 serving to effect such adjustment as required. When the desired position of the slide 70b along the lever 66b has been reached, the pancake cylinder 110 is energized to urge the binder or frictional member or pin 116 into firm engagement with the lever portion 118 and to secure the slide in adjusted position.
As will be observed, the motor 108 is located in close proximity to the pivot shaft 68a to minimize inertial forces during oscillation of the cam lever 66b. The motor is also of minimal weight and size as is the lock-up cylinder 110. The lock-up cylinder 110 must of necessity be located outwardly along the lever 66b but its minimal weight avoids any serious inertia problems.
From the foregoing it will be apparent that the various features of the feed roll drive means of the present invention cooperatively provide a highly accurate and high speed spring coiling machine. The heaviest and highest inertia element in the drive means in the form of the cam is rotated continuously while all elements between the cam and the unidirectional clutch are designed for a minimal inertia. The ability of the cam drive means to employ a 270° feed portion of the machine cycle further contributes to efficient high speed operation as does the ability of the cam to provide desired acceleration and deceleration characteristics of the feed rolls and other elements driven thereby. As indicated, the resulting production rates of 130 valve springs per minute represent a substantial improvement in machine speed.

INDUSTRIAL APPLICABILITY

The spring coiling machine of the present invention is useful in the high volume manufacture of coil springs and particularly automotive valve springs.

Claims

1. In a cyclically operable spring coiling machine (10) having a coiling station (20); the combination of at least one pair of oppositely rotatable feed rolls (12, 14, 16, 18) for intermittently advancing wire (22) longitudinally to the coiling station (20), a relatively fixed wire coiling arbor (32) at the coiling station (20), at least one relatively fixed coiling tool (34) at the coiling station (20) arranged to engage the longitudinally advancing wire (22) to obstruct the linear movement thereof whereby progressively to bend the same about the coiling arbor (32) and impart a coiling stress thereto resulting in the formation of a coil spring configuration at a leading end portion thereof, a cut-off tool (36, 38) at said coiling station (20) operable successively to sever coiled leading end portions of the wire (22) whereby to provide individual coil springs, feed roll drive gear means (74, 78, 80, 82, 84, 86) including unidirectional drive means and an operatively associated input drive gear (74), the unidirectional drive means causing said feed rolls (12, 14, 16, 18) to rotate oppositely and in wire feeding direction on rotation of said input gear (74) in a drive direction and rendering said feed rolls (12, 14, 16, 18) inoperative on rotation of said input gear (74) in an opposite and return direction, power operated means (58, 60, 66, 90) for driving said gear means (74-86) and feed rolls (12-18) including a continuously rotatable drive shaft (58), characterised by at least one feed roll cam (60) mounted on said drive shaft (58) for continuous rotation therewith, cam actuated means including a cam follower (64) and an operatively associated oscillable cam lever (66) having an output end portion movable in one and an opposite direction respectively for drive and return rotation of said input gear (74) in said feed roll gear means, a drive and connecting device (90) between said output end portion of said oscillable cam lever (66) and said input gear (74) for rotating the latter in said drive and return directions respectively on movement of said cam lever end portion in said one and opposite directions, and wire feed length adjustment means (70, 98) operatively associated with said oscillable cam lever (66) and connecting means and serving to adjust the degree of input gear drive rotation relative to cam follower movement.

2. The combination in a cyclically operable spring coiling machine as set forth in claim 1 wherein said wire feed length adjustment means (70, 98) takes the form of an adjustment device (70, 98) on said oscillable cam lever (66) for adjusting the effective length of the lever between the cam follower (64) and said output end portion of the lever driving said drive and connecting device (90).

3. The combination in a cyclically operable spring coiling machine as set forth in claim 2 wherein said adjustment device (70, 98) on said cam lever (66) takes the form of a slide (70) pivotally connected with said connecting device (90) and movable on the lever toward and away from the cam follower (64), and said device also including a lead screw (98) operable in association with the slide (70) and lever (66) to adjust the position of the slide (70) relative to the cam follower (64).

4. The combination in a cyclically operable spring coiling machine as set forth in claim 3 wherein a position fixing device (102) is provided between said slide (70) and cam lever (66) for fixing the slide (70) at selected positions along the lever (66).

5. The combination in a cyclically operable spring coiling machine as set forth in claim 2 wherein said wire feed length adjustment means (70, 98) takes the form of a slide (70) pivotally associated with said connecting device (90) and movable along said cam lever (66) toward and away from the cam follower (64), said means also including a small selectively operable power actuated device (108) connected between the lever (66) and the slide (70) for adjusting the position of the slide (70) during machine operation.

6. The combination in a cyclically operable spring coiling machine as set forth in claim 5 wherein said power actuated device takes the form of a lightweight motor (108) mounted on the cam lever adjacent the follower end thereof and an associated lead screw (98b) driven thereby and operatively engaged with the slide (70) on the lever (66).

7. The combination in a cyclically operable spring coiling machine as set forth in claim 6 wherein a second power actuated device (110) is provided for fixing the position of the slide (70) along the cam lever (66) and is selectively operable during machine operation to fix the slide (70) in selected positions.

8. The combination in a cyclically operable spring coiling machine as set forth in claim 1 wherein said input gear (74) for driving said feed rolls (12-18) takes the form of a pinion (74), and wherein said connecting means between said cam lever and gear includes rack gear means (88) operatively associated with the pinion (74).

9. The combination in a cyclically operable spring coiling machine as set forth in claim 8 wherein said connecting device includes a housing (94) mounted on a shaft (76) carrying said pinion gear (74) and movable at least through a limited arc thereon, and wherein said rack (88) is slidably received and constrained within said housing for engagement with said pinion gear (74).

10. The combination in a cyclically operable spring coiling machine as set forth in claim 8 wherein said rack means (88) is constrained for linear reciprocation in a fixed path in engagement with said pinion gear (74), and wherein said connecting device includes a connecting link (90) pivotally connected at one end with said rack (88) and at an opposite end with said one end portion of said cam lever (66).