US3783670A

US3783670A - Apparatus for the transfer of workpieces in a multistage press for the cold deformation by means of cold extrusion and the like

Info

Publication number: US3783670A
Application number: US00282183A
Authority: US
Inventors: K Nickrawietz
Original assignee: Eumuco AG fuer Maschinenbau
Current assignee: Eumuco AG fuer Maschinenbau
Priority date: 1972-08-21
Filing date: 1972-08-21
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08

Abstract

A multistage press for the cold deformation of workpieces comprising a first and second opposing toolholders capable of reciprocating relative to each other by the distance therebetween is disclosed which is characterized by an apparatus for transferring the workpieces from one working station to the next and permitting bilateral deformation of the workpieces. The apparatus comprises a plurality of die recesses in each of the said toolholders, the first toolholder having a greater number of die recesses than the second toolholder; means to displace the first toolholder laterally with respect to the second toolholder; means to displace the second toolholder longitudinally with respect to said first toolholder; ejector means associated with each die recess in the two toolholders; and an ejector press in operative communication with the ejector means and being coordinated with the deformation press to alternately transfer the workpieces from one toolholder to the other.

Description

nited States Patent 1 9 9 Nickrawietz Jan. 8, 1974 APPARATUS FOR THE TRANSFER OF Primary Examiner--Richard J. Herbst WORKPIECES IN A MULTISTAGE PRESS FOR THE COLD DEFORMATION BY MEANS OF COLD EXTRUSION AND THE LIKE Inventor: Kurt Nickrawietz, Pattscheid,

Germany Eumuco Aktiengesellschaft fur Maschinenbau, Leverkusen-Schlebusch, Germany Filed: Aug. 21, 1972 Appl. No.: 282,183

Assignee:

U.S. Cl. 72/346, 72/405 References Cited UNITED STATES PATENTS Attorney- Markva & Smith [57] ABSTRACT A multistage press for the cold deformation of workpieces comprising a first and second opposing toolholders capable of reciprocating relative to each other by the distance therebetween is disclosed which is characterized by an apparatus for transferring the workpieces from one working station to the next and permitting bilateral deformation of the workpieces. The apparatus comprises a plurality of die recesses in each of the said toolholders, the first toolholder having a greater number of die recesses than the second toolholder; means to displace the first toolholder laterally With respect to the second toolholder; means to displace the second toolholder longitudinally with respect to said first toolholder; ejector means associated with each die recess in the two toolholders; and an ejector press in operative communication with the ejector means and being coordinated with the deformation press to alternately transfer the workpieces from one toolholder to the other.

5 Claims, 9 Drawing Figures PATENYEDJAN 1914 3783.670

SHEET u 0F 9 PAIENIEU FEE-T4 3 783 670 sum 5 [IF 9 APPARATUS FOR THE TRANSFER OF WORKPIECES IN A MULTISTAGE PRESS FOR THE COLD DEFORMATION BY MEANS OF COLD EXTRUSION AND THE LIKE BACKGROUND OF THE INVENTION The invention relates to apparatus for the transfer of workpieces in a multistage press, during cold deformation by means of cold extrusion and the like, from one machining station to a subsequent station inorder to perform a unilateral or bilateral deformation of the workpieces. It is customary during cold deformation of workpieces to hold and guide the workpiece which must pass several working stages during the cold deforming, whereupon the workpiece, after its deformation in the first die, is passed in a cross-wise direction relative to the workpiece axis to the next working stage or to the next die. For transferring workpieces, the use of tongs or other holding devices is known which sieze the workpiece upon its deformation and eject it from the die. Such a transfer by means of tongs calls for either a center piece which must remain on the workpiece so that the workpiece may be seized therewith by means of tongs or the like, or for unilateral deformation of the workpiece only, since it must be held at one end which cannot be deformed and then transferred by means of the holding device on this end from one die to the other. Since it is possible for the holding and transfer equipment to become effective only in the situation where the tool parts are arranged at a distance with respect to each other, down times within a working cycle of the machine are unavoidable. Moreover, such a transfer system is expensive.

Furthermore, equipment is known with two opposite toolholders which reciprocate with respect to each other by the distance between two working stages, the workpieces being delivered from one toolholder to the other. To this effect, the toolholder which is displaceable transversely makes a'longitudinal displacement, whereas the die inset, which itself is displaceable longitudinally is supported within the toolholder against a spring so as to be longitudinally displaceable. As a result thereof, an idle stroke must also be interposed in order to ensure the transfer of the workpiece from one die to the subsequent one. A reciprocal deformation of the two shank ends with each stroke is not possible.

SUMMARY OF THE INVENTION It is an object of the invention to provide an apparatus for the transfer of workpieces in a multistage press during cold deformation between two tool members which eliminates the transfer device for the transfer of the workpiece from one die to the next and permits a direct reciprocal deformation of the two workpiece ends in each stroke. The invention is characterized in that one toolholder is provided with a greater number of die recesses and is supported to be movable only in the cross-wise direction, while the other toolholder is fitted with a lower number of die recesses and is movable only along the longitudinal axes of the die recesses. Furthermore, the two toolholders are provided with ejector-ram groups, and the ejector-ram groups of the cross-displaceable toolholder are arranged dis-- placeably in association therewith, whereas the ejector ram-group of the toolholder shiftable longitudinally is supported in said holder and an ejector press is coordinated with the deforming press.

As a result of such a design of the transfer equipment, deformation is possible with each stroke of the longitudinally displaceable toolholder. No idle stroke is necessary. The feeding of the workpiece from a die of one toolholder to the next die of the other toolholder is carried out directly, and a deformation is accomplished with the entry of the workpiece into each die recess of one toolholder or the other. As a consequence thereof, operation time is saved and the output of the machine is increased; moreover the workpiece can be deformed at both ends. The alternating deformation of the shank ends of one and the same piece is realized in such a way that upon deformation of the one shank end, the other shaft is deformed directly thereafter upon execution of the transverse displacement of the toolholder concerned, and this is effected over several stages in direct succession. The dies of the toolholders become operative reciprocally and in a direct time sequence. Such a saving in time implies a quickly operating machine with a high output.

The cold deforming machine according to the invention should advantageously be constructed in such a way that two presses fit into each other. In the actual deforming press is arranged an additional press actuating the ejectors of both sides of the deforming press. To this effect, the operations are tuned individually so that the deforming press is opened by means of the ejector press, while the deforming press deforms the workpieces.

The ejector press provided in the deforming press should suitably be designed in such a way that it has two cross beams connected with each other by anchors. One traverse extends outside the one stationary press crosspart and receives the actuator pistons for the ejectors of the transversely displacable toolholder. Theother traverse of the ejector press is displaceable on a limited path in the direction of movement of the longitudinally displaceable toolholder and within the latter. The actuator piston for the longitudinally displaceable toolholder and the actuator piston or pistons respectively for the ejector press should conveniently be housed in the other stationary cross beam.

At the outside traverse of the ejector press, two tie rods suitably engage each other and are connected with pistons which are arranged so as to be longitudinally displaceable in the stationary traverse. A pull-back surface of the piston is provided for the longitudinally shiftable toolholder. This surface is smaller than the pressure surfaces of the pistons of the ejector press, whereas, however, the pull-back surface of the piston for the longitudinally displaceable toolholder, together with the pressure surfaces of the pistons of the tie rods are greater than the pressure surfaces of the pistons of the ejector press.

In this way, the cross displacement of the one toolholder can be performed with sufficient space between the holder and the workpiece, on the one hand, and between the ejector and the holder on the other hand.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained now with the aid of the specific embodiment illustrated in the drawings.

FIG. 1 shows a diagram of the operating cycles for the production of a gear shaft by means of the hydraulic cold extrusion press of the invention;

FIG. 2 is a perspective view of the hydraulic cold extrusion press according to the invention;

FIG. 3 shows a longitudinal cut through the hydraulic cold extrusion press according to the invention with the essential part of the hydraulic control unit shown; and

FIGS. 4 to 9 schematically illustrate the various operational and motion phases of the deformation press and of the ejector press for the deformation and transfer of the workpiece.

DETAILED DESCRIPTION OF THE INVENTION In the illustrated embodiment of the hydraulic cold extrusion press 1 there is provided a bilateral deformation of the workpiece in five consecutive operations for each end of the workpiece. The starting material is a bar section 2a which, for the preparation of a collar, may be cold formed by means of a separate press 3. This operation should be carried out separately since the pressure necessary to form a collar on the workpiece must be substantially higher than for the subsequent deforming operations. Workpiece 2b fitted with a collar is fed from press 3 to press 1 in the usual manner in a cyclic process. Cold extrusion press 1 is provided with a toolholder 4 displaceable transversely relative to the longitudinal axis of dies 5a to 52, as shown by arrows 6 along the length of one die partition. The other toolholder 7 exhibiting dies 8a to 8e may be reciprocated in the longitudinal direction of the dies as shown by arrows 9. Die 5 in toolholder 4 does not serve for the deformation of the workpiece, but is the reception die for loading the toolholder 4 with workpiece 2b. Workpiece 2b is forced into die 5 with a grip fit by shoulder 10 of toolholder 7 which is shiftable longitudinally. Closing of the

toolholders

4 and 7 with respect to each other, in the case of the illustrated example of a workpiece with a collar, is carried out in each case by the abutment of the mentioned collar. Instead of using a collar to limit the entrance of the workpiece into the die, this may be accomplished by stops in the die cavity or by ejectors.

The hydraulic cold extrusion press 1 is constructed as follows:

The frame of press 1 has

stationary crossparts

11 and 12 connected at two

opposite sides

13 and 14 to form a closed frame. Toolholder 4 is supported on the stationary crosspart 12 so as to be displaceable in a crosswise direction, the displacement being carried out by means of piston 15 arranged in cylinder 16 connected to the stationary crosspart 12.

Lines

17 and 18 for the pressure medium run to cylinder 16. Longitudinally displaceable toolholder 7 is reciprocated by piston 19 sliding in cylinder 20 provided in the stationary crosspart 11 of the press. Cooperating with this deforming press is an ejector press 21 fitted with

crossbeams

22 and 23 connected by

anchors

24 and 25 to form a mobile frame. Crossbeam 22 is in a through-recess 26 of toolholder 7 so that the crossbeam and, hence, the ejector press can be displaced relative to the toolholder 7 which itself is displaceable longitudinally. The displacement of the ejector press is achieved by means of

pistons

27 and 28 which may reciprocate in

cylinders

29 and 30 which are housed in the stationary crosspart 11 of the deforming press. In toolholder 7 are provided ejectors 31 cooperating with crossbeam 22 of the ejector press. Bushings 32 are arranged in toolholder 4 which is transversely displaceable. The ejectors 33 are supported in said bushings to be longitudinally displaceable and to engage with different depths in the dies 5a to 5e of toolholder 4. Ejectors 33 move in a cross-wise direction together with toolholder 4, and the stationary crosspart 12 of press 1 is fitted with a through-recess 34.

Actuator pistons 35 are housed in crossbeam 23 of ejector press 21 for the additional motion of ejector 33. Projecting through crossbeam 23 are tie rods 36 which, at their free ends, are provided with stops 37. Tie rods 36 are displaceable longitudinally along a relatively limited path, and with the aid of pistons 38 are movable in cylinders 39 which are located in the stationary crosspart 12 of press 1.

Line 40 for the pressure medium extends via nonreturn valve 41 to control

spool valves

42 and 43. Line 44 of control spool valve 42 leads to the press surface 19a of piston 19, while line 45 leads from control spool valve 42 to press

surfaces

27a and 28a of

pistons

27 and 28 of the ejector press 21. From control piston 43, line 46 leads to the annular pull-

back surfaces

27b and 28b of

actuator pistons

27 and 28 of the ejector press 21, and the additional line 47 leads from control spool valve 43 to pull-back surface 19b of actuator piston 19 of toolholder 7 which is shiftable longitudinally. The cylindrical space of pressure surface 28a of piston 28 is connected by line 48 with the pressure surface 380 of piston 38.

Pressure oil lines

49 and 50 extend extend both the sides of actuator piston 35. The collecting chamber or tank for oil not under pressure is designated by reference numeral 51.

Lines

4O, 17, 18, 49 and 50 are connected with a pump (not illustrated), with the control switches necessarily being interconnected.

The dimensional ratios of

pistons

19, 27 and 28 are selected so as to ensure that the pull-back surface 19b of piston 19 is somewhat smaller than the pressure surfaces 27a and 28a of

pistons

27 and 28. Furthermore, the pull-back surface 19b of piston 19 together with the annular pressure surfaces 380 of pistons 38 are greater than the sum of pressure surfaces 27a and 28a of

pistons

27 and 28. In view of the smaller return movement of toolholder 7, the pressure surfaces 19b of piston 19, the pressure surfaces 27a and 28a of

pistons

27 and 28 and the pressure surfaces 38a of piston 38 are under the common pressure of the pressure medium.

Operation of the hydraulic cold extrusion press with the direct transfer of the workpiece across the toolholder occurs by means of the individual phases disclosed hereinafter.

FIG. 4 shows the starting position of the toolholder. When toolholder 7 is in a completely withdrawn position, toolholder 4 is transversely displaced into the loading position so that shoulder 10 of the longitudinally shiftable toolholder 4 is opposite the die 5 for the reception of workpiece 2b. Ejectors 33 of the transversely shiftable toolholder are positioned opposite the workpieces at a predetermined distance. Thereafter, the longitudinally displaceable toolholder 7 advances while the workpieces which have already passed on or several working phases are firmly held in dies 8a to 8e of holder 7. By applying the pressure medium on surface 19a of piston 19, toolholder 7 advances. Piston ring surface 19b of piston 19 and

surfaces

27a, 27b, 28a, 28b of

pistons

27 and 28 of the ejector press 21 are connected with the tank. Toolholder 7 is taken along ejector press 21 via crossbeam 22 without any function being performed by ejectors 31. At this point, the long ends of the workpieces are pressed into dies 5a to 5e, so that a corresponding deformation is carried out.

Since crossbeam 23 and crossbeam 22 of the ejector press 21 are displaced to the same extent, ejectors 33 are pushed back by the workpieces pressed into dies 5a to Sc. Pistons 35 as well as pistons 38 are withdrawn. At thesame time, the first die 5 is located with workpiece 2b.

After closing of the

toolholders

4 and 7, toolholder 7 returns a short distance in order to set free the short side of the workpiece for the cross displacement of toolholder 4. With this small return movement as shown by FIGS. 5 and 6, the workpieces remain in dies 5a to Sc. At this point, the surfaces 19b of piston 19, surfaces 27a and 28a of

pistons

27 and 28 of the ejector press 21 and surfaces 38a of piston 38 are under common oil pressure. Because the pull-back surface 11% is somewhat smaller than the sum of pressure surfaces 27a and 28a of the ejector press 21, the ejector press is maintained in the pulled-out position, while toolholder 7 is returned into space 26. In this way, rams 3ll meanwhile press against the workpieces, and longitudinally displaceable toolholder 7 is separated from the workpieces, so that these remain in transversely displacable toolholder 4. As soon as toolholder 7 has reached crossbeam 22, the ejector press together with toolholder 7 withdraws since surfaces 11% and 38a together are greater than

surfaces

27a and 28a. Stops 37 act on crossbeam 23 of the ejector press 211 until pistons 38 have reached the final position in cylinders 39. As a consequence thereof, the power exerted via pres sure surfaces 38a becomes inoperative. The power at' pressure surfaces 27a and 28a is then greater than at the pull-back surface 1% of piston 19 so that the return movement of the longitudinally toolholder 7 comes to a standstill at the predetermined short distance. Toolholder 4 is now displaced to the left by one die partition and takes the position of

toolholder

4 and 7 according to FIG. 7. Thereafter, the hydraulic pressure is changed so that the working surface 19a of piston 19 is under pressure, whereby toolholder 7 is shifted in the direction to toolholder 4 and a deformation of the short ends of the workpieces is achieved. During this closure stroke, the crossbeam 22 of the ejector press 21 joins the rear stop surface of the toolholder 7, thus permitting an easy-introduction of the ejectors 31 through the workpieces 2c 2g. Workpiece 2h, having passed all working cycles at both ends, is outside the path of movement of the toolholder 7 due to the transverse displacement of toolholder 4. This position of workpiece 2h with

closed toolholders

4 and 7 is shown in FIG. 3.

Now, the complete return of toolholder 7 is carried out to release the long workpiece parts from dies 5a to Be. The full return movement is achieved by pressure application on piston ring surfaces 27b and 23b of

pistons

27 and 28, with toolholder 7 being withdrawn via crossbeam 22 of the ejector press 21. At the same time,

pistons 35 in crossbeam 23 are pushed forward. The

workpieces are discharged form the dies 5 5e of the toolholder 4 crossbeam 23, piston 35 and ejectors 33, by means of ejector so that they remain firmly in the dies 8a 82 of longitudinally displaceable toolholder 7 and follow the full return position of the latter. Upon release of the workpieces from dies 5 5e, but prior to the termination of the return movement, pistons 35 are withdrawn. As a consequence thereof, ejectors 33 disengage from the workpieces and remain behind them to the extent of the stroke of piston 35. The workpieces in toolholder 7 are removed from toolholder 4 at the end of the stroke. At the same time, the finished workpiece 2h has been ejected by the ejector piston 35 concerned, whereupon toolholder 4 is displaced to the right by one die partition so that toolholder 4 passes over from the position of FIG. 9 into the starting position, i.e., the loading position of FIG. 4 or FIG. 1 respectively. The cycle then starts again. With the advance of toolholder 7, the newly fed workpiece 2b is simultaneously pushed into the first die 5 of toolholder 4, while the workpieces held in dies 8a 8e are pressed into dies 5a 5e to be deformed by them.

What is claimed is:

11. In a multistage press for the cold deformation of workpieces comprising first and second opposing toolholders capable of reciprocating relative to each other by the distance therebetween, an apparatus for transferring said workpieces from one working station to the next and permitting bilateral deformation of the workpieces, comprising a plurality of die recesses in each of said toolholders, the first toolholder having a greater number of die recesses than the second toolholder; means to displace said first toolholder laterally with respect to said second toolholder; means to displace said second toolholder longitudinally with respect to said first toolholder; ejector means associated with each die recess in the two toolholders; and an ejector press in operative communication with said ejector means and being coordinated with the said deformation press to alternately transfer said workpieces from one toolholder to the other, said ejector press comprising first and second cross-members movable longitudinally with respect to said toolholders, said first cross-member being aligned transversely at the rear side of said first toolholder and containing movable actuator means for the ejector means associated with the die recesses in the first toolholder and said second cross-member being aligned transversely at the rear side of said second toolholder, means for fixedly connecting said first and second cross-members together and piston-andcylinder means to longitudinally displace said crossmembers.

2. An apparatus for transferring workpieces according to claim 1, wherein said means for laterally displacing the first toolholder and said means for longitudinally displacing said second toolholder comprise piston-and-cylinder units fixed to a stationary base member.

3. An apparatus for transferring workpieces according to claim 2, further comprising two longitudinally displaceable tie rod members projecting through said first ejector press cross-member and being provided with stops at their ends distal to said first toolholder, said tie rod members being displaceable by means of piston-and-cylinder units."

4. An apparatus for transferring workpieces according to claim 3, wherein said piston-and-cylinder means for displacing said ejector press cross-members and said piston-and-cylinder means for longitudinally dis placing the second toolholder comprise opposing piston pressure surfaces enabling bi-lateral displacement; wherein the piston pressure surface of said displacing means for the second toolholder urging said deformation press in the open direction is smaller than the piston pressure surfaces of the displacing means for the ejector press cross-members urging said cross-members in the opposite direction to said second toolholder; and wherein said piston pressure surface of the displacing 5. An apparatus for transferring workpieces according to claim 4, further comprising a means positioned at the feed side of the longitudinally displaceable toolholder for carrying a new workpiece to be fed into the deformation press.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION f Patent No. 3, 79:3,670 Dated Janfiia'fy "s, 1974 lnventofls) Kurt Nlckrawletz' r It is certified that error 'apjpelarsin -abovia-identified patent "and that said'Letters-Patent are h ei rjb co: cted as shown "b'Iow:

Cover page, first column, between "Appl. No. 282,183" and "u.s. c1. 72/346" insert:

Foreign Application Priority-gate Signed and sealed this 10th day of September 1974.

Attest:

MoCOY M. GIBSON,- JR 0. MARSHALLDANN' Attesting Officer Commissioner of Patents USCOMM-DC 6037 6-P69 FORM Po-1o5b (10-59) fi U.S. GOVERNMENT PRINTNG OFFICE: I969 0-366-334

Claims

1. In a multistage press for the cold deformation of workpieces comprising first and second opposing toolholders capable of reciprocating relative to each other by the distancE therebetween, an apparatus for transferring said workpieces from one working station to the next and permitting bilateral deformation of the workpieces, comprising a plurality of die recesses in each of said toolholders, the first toolholder having a greater number of die recesses than the second toolholder; means to displace said first toolholder laterally with respect to said second toolholder; means to displace said second toolholder longitudinally with respect to said first toolholder; ejector means associated with each die recess in the two toolholders; and an ejector press in operative communication with said ejector means and being coordinated with the said deformation press to alternately transfer said workpieces from one toolholder to the other, said ejector press comprising first and second crossmembers movable longitudinally with respect to said toolholders, said first cross-member being aligned transversely at the rear side of said first toolholder and containing movable actuator means for the ejector means associated with the die recesses in the first toolholder and said second cross-member being aligned transversely at the rear side of said second toolholder, means for fixedly connecting said first and second cross-members together and piston-and-cylinder means to longitudinally displace said cross-members.

3. An apparatus for transferring workpieces according to claim 2, further comprising two longitudinally displaceable tie rod members projecting through said first ejector press cross-member and being provided with stops at their ends distal to said first toolholder, said tie rod members being displaceable by means of piston-and-cylinder units.

4. An apparatus for transferring workpieces according to claim 3, wherein said piston-and-cylinder means for displacing said ejector press cross-members and said piston-and-cylinder means for longitudinally displacing the second toolholder comprise opposing piston pressure surfaces enabling bi-lateral displacement; wherein the piston pressure surface of said displacing means for the second toolholder urging said deformation press in the open direction is smaller than the piston pressure surfaces of the displacing means for the ejector press cross-members urging said cross-members in the opposite direction to said second toolholder; and wherein said piston pressure surface of the displacing means urging the second toolholder in the open direction together with the piston pressure surfaces of said piston-and-cylinder means of the said two longitudinally displaceable tie rod members is larger than the said piston pressure surfaces of the displacing means for the ejector press cross-members urging said cross-members in the said direction.

5. An apparatus for transferring workpieces according to claim 4, further comprising a means positioned at the feed side of the longitudinally displaceable toolholder for carrying a new workpiece to be fed into the deformation press.