US3695088A

US3695088A - Multi-stage forming machine

Info

Publication number: US3695088A
Application number: US61070A
Authority: US
Inventors: Zia R Alvi; Victor L Heslop; Frederick A Summerlin
Original assignee: Aerpat AG
Current assignee: Aerpat AG
Priority date: 1969-08-15
Filing date: 1970-08-05
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: SU526280A3; DE2039697A1; FR2058313B1; GB1326022A; DE2039697C3; JPS5113748B1; DE2039697B2; FR2058313A1

Abstract

A machine for cold forming workpieces in which workpieces are subjected to a sequence of work operations performed by a bank of co-operating tools and dies, therebeing transfer means for transferring each workpiece through successive work stations in the bank so as to be subjected sequentially to the action of successive co-operating tools and dies. The machine has two such banks operating 180* out of phase and the transfer means of both banks are carried by a common reciprocable slide, the arrangement being such that, in one direction of its reciprocating movement, the common slide moves the transfer means of one bank in a direction which advances the workpieces in that bank to successive work stations while the transfer means of the other bank are returning, and, in the other direction of reciprocating movement of the slide, the transfer means of the other bank advance the workpieces in the other bank while those of the one bank return.

Description

United States Patent [151 3,695,088

Alvi'et a1. 1 Oct. 3, 1972 [54] MULTI-STAGE FORll/IING MACHINE 3,460,735 8/1969 AkiraShibata ..72/335 [72] Inventors gs gz g j i z l Primary ExammerCharles W. Lanham Frederick summerfin Harper; Assistant Examiner-Gene P. Crosby den an of England Attorny-Kemon, Palmer & Estabrook [73] Assignee: Aerpat A.G.,Zug, Switzerland [57] ABSTRACT 4 [22] Filed: Aug. 5, 1970 A machine for cold forming workpieces in which workpieces are subjected to a sequence of work [21] Appl' 6l070 operations performed by a bank of.'co-operating tools and dies, therebeing transfer means for transferring [30] Foreign Application Priority Data each workpiece through successive work stations in I the bank so as to be subjected sequentially to the acl51969 Great tion of successive co-operating tools and dies. The machine has two such banks operating 180 out of fits-(glphase a d the transfer means f b th banks are cap I I I a common reciprocable Slide the arrangement 8 ?fg z ggqg jggf i 3 being such that, in one direction of its reciprocating I movement, the common slide moves the transfer R f Ct d means of one bank in a direction which advances the [56] e erences e workpieces in that bank to successive work stations UNITED STATESv PATENTS while the transfer means of the other bank are retuming, and, in the other direction of reciprocating move- 3 3 2/ 1968 Brfldlee "72/335 ment of the slide, the transfer means of the other bank 22,122 33 advance the workpieces in the other bank while those 2. ms of the one b k return- 2,279,417 4/1942 Stevens ..72/405 1,005,622 10/191 1 Eisenbeis ..72/405 1 Claim, 11 Drawing Figures PATENTEnuma m2 3,695,088

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SHEET USUF 10 6 t forn iys PATENTED ET 3 I 72 SHEET U8UF 1O PATENTEDUET 3 I972 SHEET 10 0F 10 1 MULTI-STAGE FORMING MACHINE The invention relates to a multi-stage forming machine of the type comprising:

a plurality of dies for receiving workpieces successively;

a plurality of toolholders each associated with one of the dies, each for holding a tool and each reciprocable to bring the tool to strike a workpiece received in the associated die;

means for reciprocating the toolholders substantially in unison so that the tools are all withdrawn from the dies at least for a common withdrawal period in each reciprocation; and transfer means for transferring workpieces successively from one die to the next during each common withdrawal period of the tools, the transfer means comprising workpiece-gripping means and a reciprocable transfer slide, reciprocation of the transfer slide in appropriate relationship to the reciprocation of the toolholders causing, during advance movement, advance of the workpiece-gripping means from one die to the next and, during return movement, return of the workpiece-gripping means from the said next die to the said one die. Such a-multi-stage forming machine is hereinafter referred to as a multi-Stage forming machine of the type defined. Such machines, and their manner of operation, are well known to those skilled in the art of manufacturing large numbers of small metal articles, e.g. rivets.

The invention provides, in one of its aspects, a multistage forming machine of the type defined, which machine comprises:

two banks each consisting of a plurality of dies and associated toolholders;

means for reciprocating thetoolholders of one bank substantially 180 out of phase with the toolholders of the second bank;

and a common reciprocable transfer slide for the transfer means of both banks;

the arrangement being such that when the common reciprocable transfer slide is moving in one sense the workpiece-gripping means of the first bank are advancing while the workpiece-gripping means of the second bank are returning, and when the common reciprocable transfer slide is moving in the opposite sense the workpiece-gripping means of the first bank are returning while the workpiecegripping means of the second bank are advancing.

The common reciprocable transfer slide may comprise a single member. However, in a preferred embodiment of the invention, it comprises two members, each associated with the workpiece-gripping means of one of the banks, linked togetherfor movement in unison. Preferably the members are linked together by an adjustable linkage which provides for relative adjustment of the two members in the direction of their reciprocation.

.In a preferred embodiment of the invention, the two banks are positioned relatively end-to-end in a straight line, and the machine is arranged so that workpieces in each bank are moved progressively towards the adjacent ends of the banks where there may be provided a common discharge station for workpieces from both banks. In this case, workpieces are discharged at the discharge station from the two banks altemately. Alternatively, separate adjacent discharge stations, one for each bank, may be provided at the adjacent ends of the whereby after being struck by the associated tool the workpiece can be fully ejected from the die before being gripped by the workpiece-gripping means,

, without tending to tip sideways out of its vertical position.

A specific embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a front elevation of a multi-stage forming machine;

FIG. 2 is an elevation of one end of the machine;

FIG. 3 is an elevation of the other end of the machine (part being omitted);

FIG. 4 is a plan view of the transfer means;

FIG. 5 is a diagrammatic section through the machine showing the relative positions of some cams;

FIG. 6 is a plan view, on the line VI VI of FIG. 5,

of the transfer slide reciprocating means;

FIGS. 7 and 8 are front elevations of the machine, partially simplified, illustrating the toolholders and transfer slide attwo positions respectively apart in their cycles of reciprocation; I

FIGS. 9 and 10 are sections (on the lines IX IX of FIG. 10 and X X of FIG. 9 respectively) at right-angles to each other, showing part of the wire feed and thecropping means; and

FIG. 11 is a cross-section showing by way of illustration, a die and tool of one of the banks.

The twin bank multi-stage forming machine of this example has a general arrangement which will be ap-' parent from FIGS. 1, 2, 3 and 4. It is built in a strong frame 11 supported on a substantial base 12. The The machine has two banks A and B adjacent each other in end-to-end relationship, each bank occupying one half of the machine frame. The two banks are substantially identical with each other, except that one is substantially a mirror image of the other. Each bank comprises a slug cropping station, at which a slug is cropped from the end of a wire feed to form a workpiece, four workpiece forming stages through which the workpiece passes successively, and a discharge station at which the workpieces are discharged from the machine. In this example, there is a single discharge station 13 which is common to both banks, positioned at the junction between the banks in the center of the machine, and the two slug cropping stages are positioned oneat the outer end of each bank.

Bank A comprises four dies DAI, DA2, DA3 and DA4, and bank B likewise comprises four dies DB1, DB2, DB3 and DB4. (In FIG. :4, the dies are represented schematically, the actual construction of the die forming no part of the present invention). The common discharge station 13 is situated midway between the two final dies DA4, DB4. The spacing between each die and the next is the same for both banks, and is also the same as the distance between each final stage die DA4, DB4 and the common discharge station 13.

At the outer end of each bank A, B, is situated a cropping station CA, CB respectively, the positions of the center line of each being indicated in FIG. 4. FIG. 4 also illustrates the transfer means. This comprises workpiece-gripping means associated with each die, in the form of a pair of fingers. Associated with bank A are four pairs of fingers FAl, FA2, FA3 and FA4 and an arm 14A. Likewise, associated with bank B are four pairs of fingers FBI, FB2, F83 and FB4 and an arm 14B.

The pairs of transfer fingers of both banks are carried toothed arms 27, 28, each constituting part of a spur gear. Each closing camis elongated in the direction of reciprocation of thetransfer slide so that the follower roller 25 can be engaged by the cam face throughout the travel of the slide. When the cam is moved into the open position (as in bank A in FIG. 4) it engages the roller 25 and causes the two arms to rotate about their pivot to open the fingers. When the cam is in its closed position (as in bank B in FIG. 4) the tension coil spring of each pair of arms closes the fingers. Movement of each finger closing cam FCAI, FCA2, FCA3, FCA4,

. FCBl, FCBZ, FCB3, FCB4 is actuated by an associated on a reciprocable slide 16, which comprises two separate members 16A and 16B rigidly connected together by' a linkage 17. The member 16A carries the set of four pairs of fingers and the arm 14A of bank A and the member 163 carries the set of four pairs of fingers and the arm 14B of bank B. The linkage 17 can be adjusted to adjust the distance between the two members 16A and 16B in the direction of reciprocation of the slide 16, in order to correctly align the two sets of fingers and arms relatively to each other. The arms 14A and 14B are fixed in position relative'to the slide members 16A and 16B respectively and the fingers of each pair are movably mounted on the slide members so as to be capable of gripping and releasing workpieces.

When the machine is operating, the first pair of fingers FAl transfer a cropped slug from the cropping station CA to the die DAl while the second pair of fingers FA2 transfer a workpiece from die DAl to die DA2, and so on. Workpieces from the two final dies DA4, DB4 are transferred to the discharge station 13 by means of-the fixed arms 14A, 148 respectively. Each fixed arm has a circular workpiece receiving aperture 15 near its end in which the workpiece is carried from the final stage die to the discharge station. As the slide reciprocates, the apertures 15 are moved between positions in which they are aligned alternately with the center of the final die and the discharge station.

The general construction and method of operation of the pairs of transfer fingers used in this machine is well known to those skilled in the art of multi-stage-progressive cold forming machines, and will only briefly be described here. Taking as an example the pair of fingers FA], these two fingers are each mounted at one end of an arm 18, 19 respectively. Each arm is pivoted approximately mid way along its length on a pillar 21, 22 respectively. The other end of the two arms are joined by means of a tension coil spring 23 which urges the two fingers FAl together. In FIG. 4, the fingers of bank B are shown in their closed position and the fingers of bank A are shown open. Adjustable stops are provided for adjusting the extent to which the fingers close on each other to properly grasp the workpiece. The finger opening mechanism is illustrated in FIG. 4 with reference to the pair of fingers FA4. Secured to one finger of the pair is an arm 24 having at its remote end a cam follower roller 25 which engages with an elongated closing cam FCA4. The two fingers are coupled together for opposing pivoting movement about their respective pivots by means of interengaging

rotating cam

30A or 30B (for banks A and B respectively) on a camshaft 29 in the machine. In general, the finger closing cams of each bank move in synchronism, but minoradjustments in the phase of their relative movements are possible.

As illustrated in FIG. 1, the transfer slide 16 reciprocates in a machine slideway in the front lower cross member 31 of the machine frame. The mechanism causing its reciprocation will be described later.

Also as illustrated in FIG. 1, associated with each die in each bank is a toolholder which is reciprocable vertically to cause a tool mounted in the lower end of the toolholder to strike the workpiece in the associated die when the toolholder reaches the bottom of its stroke. Thus in bank A there are four toolholders TAl, TA2, TA3 and TA4 and likewise in bank B, there are four toolholders TBl, TB2, TB3 and TB4. The design and operation of the particular tools secured to the bottoms of the toolholders of each bank is arranged so that each tool provides a further stage in the forming of the workpiece as the workpiece progresses from the slug cropping station to the discharge station but otherwise fonns no part of the present invention, and will not be described further. In this machine, each toolholder is provided in the fonn of a vertically disposed ram reciprocable in suitable slide bearings in the frame middle cross member 32. Each toolholder is reciprocated by means of a pair of cams, one for raising the toolholder and one for lowering it. The four toolholders of bank A have respectively four raising cams RCAl, RCA2, RCA3 and RCA4, and four lowering cams LCAl, LCA2, LCA3 and LCA4. Likewise, the toolholders of bank B have respectively four raising carns RCBl, RCB2, RCB3 and RCB4, and four lowering cams LCBl, LCB2, LCB3 and LCB4. A suitable separate follower is provided for each raising and lowering cam respectively, secured to the upper part of the associated toolholder. All the raising and lowering cams are mounted on the same main camshaft 33. The cams are generally arranged so that the four toolholders of one bank are raised when the four toolholders of the other bank are lowered i.e. the reciprocation of the two banks of toolholders is substantially out of phase. Each cam is suitably shaped for the function which it performs, and provision is made for minor adjustment of the phase of each cam in order to permit the most efficient working of the machine.

Associated with each bank of the machine is means for feeding wire to the cropping station of that bank.

The wire feed means associated with bank A will be described, that associated with bank B being similar. As shown in FIG. 2, a feed reel 35 of wire stock is situated on the floor behind the machine, supported in a suitable stand 36. The wire 37 passes upwardly and over a guide pulley 38 secured to the outer upper end of an arm 39 mounted on the upper part of the machine frame. The wire then passes forwardly and downwardly, and passes vertically downward through two straighteners 40. The straightened wire then passes vertically downwards just inside the side of the machine frame and behind the camshaft 33. While within the machine frame and adjacent the reciprocating toolholders' and camshaft, the wire passes through a tube 41 which protects it from contamination by lubricating oil splashes. At the bottom end of the tube 41 the wire emerges into a feeding device and cropping means, which are shown in FIGS. 9 and 10.

The feeding device comprises two

feed wheels

42 and 43 which touch tangentially to provide a nip, the peripheral face of each wheel having in it a groove 44 of part circular cross-section to receive and grip the wire. These two feed wheels are geared together by means of gear wheels 45 and 46 (only a few teeth of each gear wheel are illustrated in FIG. 9) for rotation in unison in opposite directions to feed the wire stock downwards through their nip. The feed wheels are rotated intermittently by means of a drive to the gear wheel 46, comprising a ratchet device 47 driven by a connecting rod 48, the remote end of the rod 48 being secured ina slide 49 along a rockingarm 51. The rocking arm 51 pivots about a pin 52, and is oscillated by means of a follower arm 55 also secured to the pin 52 and spring urged into contact with a cam 54 on a shaft 55. The shaft 55 is rotated continuously in synchronism with the remainder of the machine. The length of wire fed at each revolution of the shaft 55 is determined by the position of the upper end of the rod 48 along the slide 49 in the oscillating arm 51. The position of the upper end of the rod 48 relative to the slide 49 is adjustable so as to vary the angle through which the

feed wheels

42 and 43 are advanced at each revolution of the shaft 55 and so to adjust the length of wire fed at each revolution.

Below the

feed wheels

42, 43 the wire 37 passes through a further short length 56 of protective tubing and then through a fixed cropping die 57 formed of hardened steel. This cooperates with a similar movable hardened steel cropping die 58 carried in a cropping slide 59. The cropping slide 59 is reciprocable between two positions, i.e. a rearward position (shown in FIG. 9 in solid lines) in which the-cropping dies 58 and 57 are superposed, and a forward position (illustrated in FIG.

9 in broken lines and with reference numerals with the suffix a in which the movable cropping die 58 is in alignment with the center of the first stage fingers FAl. The cropping slide 59 is reciprocated by means of a suitable rocker mechanism which is actuated by a cam shaftdriven in synchronism with the remainder of the machine. When the cropping slide 59 is in its rearward position with the movable cropping die 58 aligned with the fixed cropping die 57, a length of wire is fed downwardly through the die 57 into the die 58 by the

feed wheels

42, 43. The maximum length of wire which can be fed into the movable cropping die 58 is determined by a positive stop provided by the upper end of a pin 61 underneath the die 58 within the slide 59. The lower end of the pin 61 rests on and slides along the provided with ejectors, EAI, EA2, EA3 and EA4 upper face of abar 62, the height of which is adjustable by means of a screw device 63-. Thus the length of wire cropped to provide a slug or billet is accurately adjustable.

When the cropping slide 59 moves from its rearward position, the wire within the movable cropping die 58 is sheared from the stock at the interface of the two dies 57, 58 to provide a slug. The slug is supported in the die 58 on the top end of the pin 61 and is carried forward within the die 58 until the slide 59 reaches its forward position, indicated by numeral 590 and shown in broken lines in FIG. 9. This position is also shown (in full lines) in FIG. 10. When the slide 59 reaches its forward position, the pin 61 is then immediately above an ejector 64, the upper end of which passes through the block 62. The ejector 64 is then actuated (by means which will be described later) to eject the cropped-slug from the cropper die 58, so that it stands vertically upon the upper end of pin 61. The slug is then grasped by the fingers FAl and transferred to the die DAl of the first stage of bank A.

The four dies DAl, DA2, DA3 and DA4 are each respectively, which are indicated in FIG. 1 and also, in outline, in FIG. 10. Likewise the dies DB1, DB2, DB3

and DB4 of bank B have four ejectors EBl, EH2, BB3

and BB4. Each ejector is actuated by means of a .separate ejector cam, the lower end of each ejector resting on a rocker arm and the underside of the rocker arm contacting the ejector cam. The eight rocker arms RA1,'RA2, RA3, RA4, RBI, RB2, RB3, RB4 and the eight ejector cams ECAl, ECA2, ECA3, ECA4, ECBl, ECB2, ECB3, ECB4 respectively are indicated in FIG. 1. The ejector cams are mounted on a cam-shaft 65 passing through the lower part of the machine frame. The two cropping ejectors are also actuated by ejector cams on the shaft 65, but these ejectors and cams are not illustrated in FIG. 1.

FIG. 11 illustrates, in somewhat simplified form, the first stage of bank A. The ejector EA] includes an ejector pin 66 which is a close sliding fit within the bore of the die DAl. The pin 66 has a flat upper end 67 on which rests the workpiece 68. FIG. 11 shows the position when the workpiece 68 has been struck by the tool 69 in the bottom of the toolholder ram TA1 which has now withdrawn upwards. The ejector pin 66 is nearing its uppermost position, and the workpiece 68 is in a vertical position, resting on the upper end 67 of the pin 66. The workpiece 68 remains in this vertical position as the ejector pin 66 completes its upward travel, completely ejecting the workpiece 68 from the die. The workpiece 68 is then grasped by the fingers FAl and transferred to the next die.

Referring now to FIGS. 1 2 and 3 this multistage forming machine is powered by an electric motor 71 which is connected by belt drive 72 to the input of a variable speed device 73 having a speed control knob 74. The output drive from the device 73 is transmitted through belt drive 75 to the input of the pneumatically. operated clutch 76. This clutch is connected by a pneumatic pipe 77 (FIG. 1) through a suitable control valve to source of compressed air. The output shaft 78 of the clutch carries a spur gear 79 in mesh with an idler gear 81 (only part of which is seen in FIG. 1). The idler gear 81 is in mesh with a large gear wheel 82 secured to one end. of the main camshaft 33 outside one end of the machine frame 1l;- The main camshaft 33 runs completely across the machine and extends through the opposite end of the machine frame, where it carries a spur gear 83 and a bevel gear 84. The spur gear 83 drives, in succession, an idler spur gear 85, spur gear 86 and bevel gear 87 secured to the spur gear 86. The

bevel gear 87 meshes with a bevel gear 88 on the top end of a short vertical layshaft, the bottom end of which carries another bevel gear 89 in mesh with a bevel gear 91 mounted on a horizontal shaft. This horizontal shaft is connected through suitable gearing to drive the wire feed deviceand cropping device of bank A at that end of the machine. The bevel gear 91 is secured to a shaft 92 which extends back across the machine frame to drive, through suitable gearing, the wire feed device and cropping device of bank B atthe other end of the machine. v

The bevel gear 84 on the end of the main camshaft 33 is in mesh with a bevel gear 93 on the upper end of a long vertical layshaft 94. To the lower end of this layshaft is secured a bevel gear 95 in mesh with a bevel gear 96 secured to the ejector camshaft 65. Thus the ejector camshaft is driven in synchronism with the main camshaft 33. The 'layshaft 94 also carries a bevel gear 96" which is in mesh with a bevel gear 97. This drives, through a suitable right-angle gear box 98 the camshaft 29 on which are the rotating cams 30A, 308. Thus the finger closing camshaft 29 is also driven in synchronism with the main camshaft 33. The layshaft 94 also carries an eccentric cam 99 which drives the transfer slide 16. The left hand end of the transfer slide (as viewed in FIG. 1) is connected, by means of a dog leg bracket 101, with a 'cam follower slide 102 which can reciprocate in a suitable slideway in a bracket 103 extending from the left handend of the machine frame. The upper face of the cam follower slide carries two

cam follower rollers

104 and 105, the distance between which is a fit on the longest diameter of the eccentric cam 99. As the cam 99 rotates, the transfer slide is driven backwards and forwards in synchronism with the'rotation ,of the layshaft 94, i.e. in synchronism with the rotation of the main camshaft 33. FIG. 6 shows in solid lines the position of cam 99 and

followers

104, 105 when the transfer slide 16 is in its most leftward position (as viewed in FIG. I), and shows ih broken lines the positions of those parts when the transfer slide is in its most rightward position.

The movements of the two banks of the machine are arranged so that they are substantially 180 out of phase with each other. This is illustrated by a comparison of FIGS. 7 and 8. FIG. 7 shows the situation in which the transfer slide 16 is at the left hand end of its travel, the toolholders TAl, TAZ, TA3 and TA4, and theejectors EAl, EA2, EA3 and EA4, of the bank A being all in their fully raised position, and the toolholders T131, T32, T83 and TB4, of bank B all being in their fully lowered positions. FIG. 8 illustrates the position when the main camshaft has rotated through 180 from the position shown in FIG. 7. In FIG. 8, the transfer slide 16 is at the right hand end of its travel, the

, toolholders and ejectors of bank A are in their fully lowered positions, and the toolholders and ejectors of bank B are in their fully raised positions.

The other corresponding working parts of the two banks are also respectively 180 out of phase. FIG. 5 illustrates. the way in whichvarious cams of the two banks respectively are 180 out of phase. In FIG. 5, there are shown in solid lines the position of the main raising cam RCAl of the first stage of bank A, the ejector cam ECAI of stage 1 of bank A and the finger closing cam 30A of stage 1 of bank A. In broken lines are shown the positions of the corresponding main raising cam RCBl of stage 1 of bank B, the ejector cam ECBl of stage 1 of bank B, and the finger closing cam 30B of stage 1 of bank B. It will be seen that in each case, the cam of bank B is 180 out of phase with respect to the corresponding cam in bank A. It should be noted that FIG. 5 is merely intended to illustrate this feature, and that the relative angular positions of the different types of cams, i.e. toolholderraising cam, ejector cam, and fingerclosing cam, of either bank are not necessarily accurately shown in FIG. 5.

The multi-stage forming machine described in the, foregoing example is advantageous in a number of ways. Since the two banks of the machine are 180 out of phase, the loads on the camshafts and their associated driving gear are more evenly distributed than if all the loads were taken at only one point in the cycle of rotation. The use of a single transfer slide for both banks of the machine means that the machine occupies less space than two separate single bank machines. In practice, the double bank machine of the above example occupies about three-quarters of the space which would be occupied by two separate single bank machines immediately adjacent each other. This constitutes a valuable saving of floor space in a factory. The fact that a workpiece in the machine is at all stages in a vertical position has the advantage that the workpiece does not tend to topple sideways or downwards, as occurs with multi-stage forming machines in which workpieces are horizontal. Thus the machine of this example is much less prone to jamming than machines with horizontal workpieces. It will also handle much shorter blanks and workpieces, since these can be fully ejected from the dies before being gripped by the transfer fingers.

The invention is not restricted to the details of the foregoing example. For instance, instead of the single discharge station for the finished workpieces of both banks, it would be possible to provide separate discharge stations, so that the workpieces produced by one bank are collected separately from those produced by the other bank. This could be achieved on the machine of the above example by providing a movable deflector plate at the discharge station which moves in synchronism with the transfer slide to deflect the workpieces from one bank in one direction and the workpieces from the other bank in another direction. Alternatively, the two banks could be moved slightly apart, so that the distance between the two last stage dies DA4 and DB4 is more than twice the distance between one die and the next, thus providing the two spaced apart discharge stations for the two banks. When the workpieces manufactured by the two banks respectively are collected separately, the tooling of each bank may be arranged so that the two banks form articles of different shapes. When this is so, it is desirable that the loads on each half of the main cam-shaft are kept as near as possible equal to each other.

Each bank of the machine need not contain four stages, but could contain two, three, five, six or even more stages. The invention could be applied to a.

machine with a somewhat different form of transfer mechanism, provided that the transfer mechanism utilizes a reciprocating transfer slide and that a common transfer slide is used for the two banks.

We claim: 1. A multi-stage forming machine of the type defined, which machine comprises:

first and second banks, each having a plurality of dies, associated toolholders, workpiece-gripping means and transfer means; means for reciprocating the toolholders of said first bank substantially 180 out of phase with the toolholders of said second bank; I a reciprocable transfer slide common to the transfer means of both said banks; the arrangement being such that when the said reciprocable transferslide is moving in one sense the workpiece-gripping means of the said second bank are returning, and when the said common reciprocable transfer slide is moving in the opposite sense the workpiece-gripping means of the said first bank are. returning while the workpiecegripping means of the said-second bank are advancing;

thesaidcommon reciprocable transfer slide compris-

Claims

1. A multi-stage forming machine of the type defined, which machine comprises: first and second banks, each having a plurality of dies, associated toolholders, workpiece-gripping means and transfer means; means for reciprocating the toolholders of said first bank substantially 180* out of phase with the toolholders of said second bank; a reciprocable transfer slide common to the transfer means of both said banks; the arrangement being such that when the said reciprocable transfer slide is moving in one sense the workpiece-gripping means of the said second bank are returning, and when the said common reciprocable transfer slide is moving in the opposite sense the workpiece-gripping means of the said first bank are returning while the workpiece-gripping means of the said second bank are advancing; the said common reciprocable transfer slide comprising first and second members, said first member associated with the said workpiece-gripping means of said first bank and said second member associated with the said workpiece-gripping means of said second bank, said first and second members being linked together for movement in unison by an adjustable linkage which provides for relative adjustment of said first member and said second member in the direction of their reciprocation.