EP0041690B2 - Multistage metal-forming machine - Google Patents

Abstract

A blank (17), which has been sheared off from a coil of wire or from a rod, is rotated through 90 DEG , this rotation being required in connection with the forging of this blank. The gripping-jaws (19, 20), serving for the purpose of transport from one station to the adjacent metal-working station, are attached, for this purpose, to rotating devices (9c, 9d), which are mounted in a manner permitting rotation and are located, on the one hand, on a guide part (7a, 7b) which is driven to reciprocate (A) and to oscillate about an axis (93), and, on the other hand, are anchored to the stationary die-holder (3) via a guiding mechanism (23a, 23b). The guiding mechanism can be regarded as a spatial double-link mechanism, possessing a connecting rod (24), a coupling link (25), a stationary pin-joint (28), a ball-joint (30), and a pin-joint (29a, 29b) which travels with the rotation device (9c, 9d). The components are arranged in such a way that the greatest part of the intended 90 DEG rotation of the blank takes place in the first half of the translational transport movement.

Description

The present invention relates to a multi-stage forming machine for chipless forming of blanks, according to the first part of claim 1. Such a machine is known from DE-B No. 1627519.

In conventional multi-stage forming machines that form parts directly from the wire ring or bars, the starting material is pulled in the direction of the press axis next to the press slide against a stop and sheared off with a shear knife. The shear carriage also serves as a feed of the sheared blank in front of the 1st forming station or a loading station, the longitudinal axis of the blank remaining parallel to the press axis.

If it is now a matter of forming a pressed part whose transverse extent, in particular in one direction, is many times larger than the longitudinal dimensions, it can be very difficult or even impossible to produce such parts on such multi-stage presses because of the large degree of deformation and thus large pressing forces.

Devices are known on such forming machines, by means of which blanks or pressed parts can be rotated through 180 °. The rotary movement which can be achieved with these known devices, however, inevitably proceeds in such a way that each section of the path traversed in translation corresponds to an equal fraction of the total angle of rotation. On the last third of the transport movement, however, the rotation should, if possible, be largely completed, at least apart from a slight remaining rotation, in order to avoid a collision with the adjacent die or a structural modification thereof.

It is therefore the object of the present invention to propose a device for rotating a blank by practically 90 °, which rotates the blank at the beginning of the translational movement by larger angular units than in the last section of the same, so that the blank is already considerably more midway, for example than by 45 °, e.g. B. was rotated by 60 °. The device is also to be distinguished from the known designs by its structural simplicity.

This object is achieved according to the invention by the combination of features defined in independent claim 1. Preferred embodiments are defined in the dependent claims.

• Fig. 1 ist eine vereinfachte Perspektivdarstellung des für den vorliegenden Zusammenhang relevanten Teils einer vierstufigen Umformmaschine ;
• Fig. 2 veranschaulicht schematisch den Bewegungsablauf des verwendeten Führungsgetriebes ;
• Fig. 3 zeigt verschiedene Phasen der Drehbewegung des Rohlings ;
• Fig. 4 ist ein Vertikalschnitt längs einer in der Zangenachse liegenden Ebene ;
• Fig. 5 ist ein Vertikalschnitt längs der Linie V-V in Fig. 4, und
• Fig. 6 veranschaulicht die Ausführung der Zangenbacken für den kleinsten und den grössten Rohling.

The invention is described below using an exemplary embodiment with reference to the accompanying drawings.

• 1 is a simplified perspective illustration of the part of a four-stage forming machine relevant to the present context;
• Fig. 2 illustrates schematically the sequence of movements of the guide gear used;
• Fig. 3 shows different phases of the rotational movement of the blank;
• 4 is a vertical section along a plane lying in the axis of the pliers;
• Fig. 5 is a vertical section along the line VV in Fig. 4, and
• Fig. 6 illustrates the design of the jaws for the smallest and the largest blank.

1, a lower die holder 2 with four recesses for receiving dies is attached to a press frame 1. Four die holder covers 3, 4, 5 and 6 are attached above it. Tongs carrier boxes (guide parts) 7a, 7b are located above and below these die holders. These pliers carrier boxes are each attached to a shaft (main shaft) 8 by means of a clamp connection and have the task of connecting the pliers to be described with the shafts 8, of which only the upper one is visible. Each of these shafts 8 is rotatably and longitudinally displaceably mounted in the press frame 1 and both are in exactly the same direction in the direction of arrow A or in opposite directions in the direction of arrow B, with A representing a translatory movement in the direction of the shaft axis 93 and B an angular movement about the same axis. A drive mechanism, not shown, transmits to these shafts the movement which is necessary for transporting the compacts from one forming station to the next and for the empty return.

This sequence of movements takes place in two parts: on the one hand as a transverse transport movement of the compacts from one die to the other (arrow A), on the other hand for opening and closing the pliers, or for gripping or releasing the compacts (swiveling movement around shaft 8, arrow B).

Three pairs of pliers 9, 10, 11 are releasably attached to the front of the pliers carrier box 7a, 7b. While the pairs of pliers 10 and 11 now correspond to the known shape and are provided with fixed lower grippers 12 and spring-supported upper grippers 13, the first pair of pliers was replaced by a rotatable device (pliers carrier) 9a and 9b, respectively.

The wire or rod is retracted in the axis 14 in the direction of the arrow against an adjustable stop (not shown), which adjusts the section length, and is sheared off with the shear knife 15 shown schematically.

The sheared section is held in place by a device (not shown) on the shear knife 15 and brought to the first station. In the above exemplary embodiment, this is not the first deforming station, but a pure holding station, in which the section is held until it is taken over by the tongs 9a / 9b. A protruding from the first punch tool of the advancing press slide and resiliently supported holding pin 16 presses the sheared blank 17 out of the holding device on the shear knife against a stop pin 18 which was installed in the opening provided instead of a first die. The holding pin 16 holds the blank until the pair of pliers (pliers carrier), designated as a whole by 9, which has moved to the left end position with the transverse transport carriers, has gripped the latter by the pivoting movements B, while the invisible one, which is to be thought in front of the drawing plane Press carriage goes back to its rear position, and thus also pulls back the holding pin 16. The cross transport beams are now moved to their right end position. During this movement, an upper and a lower gripper 19 or 20, which is rotatable in the bearing holders 22a and 22b, rotates through 90 ° about the vertical axis 21. This gripping movement is obtained by a spatial, ie three-dimensionally movable two-stroke gear 23a and 23b , which has the function of a guide gear and whose task is to inevitably guide the pliers 9 holding the blank 17 during their translation movement in such a way that on the one hand there is a rotation of the blank by 90 ° with respect to the vertical axis 21 and on the other hand this rotation to the translatory movement is coordinated in such a way that a large part of the angular movement takes place in the first half of the translatory tong path. The aim of this is to ensure that the guide gear required for its movement takes up the smallest possible space and, in particular, to the adjacent die housings that there are no, or only insignificant, design changes, such as, for example, B. recesses must be made.

Each of the spatial two-stroke gearbox is composed of a link 24 and a coupling 25. The link 24 has a bearing bush at its rear end, which is rotatably mounted on a fixed pin, according to FIG. 5, about the axis 28. The connection between the link 24 and the coupling 25 forms a ball joint 30, while the coupling 25 has at its other end a pivot which in the part (transmission member) 9c (top) or 9d (bottom) of the device 9 which can be pivoted about the axis 21 engages and is rotatably supported there about the axis 29a (top) or 29b (bottom).

Fig. 2 shows schematically the representation of the sequence of movements of the spatial two-stroke gear, projected onto a horizontal plane. The solid lines show the position of the guide gear when the transverse transport is in the right end position, i.e. the compact 17 is rotated by 90 ° in front of the forming station, while the left end position is shown in broken lines, so the compact is still in position how it was brought into the charging station by the clipper.

The handlebar 24 is thus rotatably attached at one end to a fixed bearing about the vertical axis 28. This enables the other end, which is connected to the coupling 25 by the ball joint 30, to move on an arc 31, dash-dotted in FIG. 2. The coupling 25 is provided at its gripper-side end opposite the ball joint 30 with a pivot pin which engages in the part 9c or 9d of the device 9 which can be rotated about the vertical axis 21 and is rotatable about the axis 29a / 29b.

If the pliers carrier, which is guided in a straight line by the shaft 8, now moves from the left end position (the two-stroke transmission 23 is therefore in the position shown in broken lines) into the right end position (drawn out in FIG. 2), the pliers rotation axis moves from 21 'along the Line 32 to 21, and the ball joint point follows the circular arc 31 from 30 'to 30. Due to the selected geometry, the coupling 25, which is guided on the one hand on the arc 31 and on the other hand on the straight line 32, is rotated by 90 °, at least as long as the gear (as shown in Fig. 2) moves in the projection plane, represented by the distance 25a 'and 25a. Since the pivot pin, which forms the axis 29 and is fastened in the coupling 25, engages in the device 9 which can be rotated about the vertical axis 21, it is thus also rotated through 90 °.

6 shows the takeover of the rotated blank 33 by the spring pin 35 installed in the second punch 34 of the press slide and the die 36. By moving the press slide 34 forward, the blank 33 is pressed out of the pliers jaws 37, 38 by the spring pin or pins 35 until the blank rests on the engraving 39 of the die. The shape of the pliers jaws 37, 38 is designed such that the blank can be ejected on the die side, but is guided until it is pressed against the engraving 39 of the die 36, while it rests on a shoulder 40 on the other side . Now that the blank 33 is held with the spring pin 35, the upper and lower pliers carrier box pivot about the shaft 8 by a certain amount (arrow B, Fig. 1), so the pliers jaws let go of the blank, i. H. the pliers open and make room for the approaching punch 34. Because of the pivoting up of the tong holder box when returning to the starting position, it is necessary to pivot the joint 30 as a ball joint and the coupling 25 at their coupling point with the rotatable device 9c / 9d, on which the jaws 37 and 38 are located, about the axis 29 to execute. This ensures that the device 9 is turned back into the starting position even when the pliers are open. Due to the described swiveling, which causes the tongs to open, the rotatable device 9 is rotated by a small, non-influencing angle, which when swiveling back, i. H. the pincer closing, is exactly compensated again.

Fig. 6 shows the jaw design for the largest (dash-dotted) and the smallest blank. The areas between the pads 41 (Fig. 4) are slanted to prevent dirt from accumulating.

4 shows a central vertical section through the pair of pliers 9. A bearing holder 43 is screwed onto the plier carrier box 7b by means of screws 44. In the bearing holder 43 there are two plain bearing bushes 45 in which the rotating part (transmission member) 46 of the pliers unit is mounted. The axial position results from a shoulder 47 and a cover 48 screwed onto the lower end of the rotating part 46. Above the mounting of the rotating part 46, this has an opening for a bearing bush 49, into which a pin 50 rotatably engages, which firmly engages with the Coupling 25 is connected. The coupling 25 could encompass the pin 50 in a fork-like manner from both end faces. To rule out the risk of contamination, the coupling 25 engages as u. a. 1 shows, only from one side on the pin 50 to which it is attached by known means. Also firmly connected to the coupling 25 is a housing 51 which has a slot s to the rear (FIG. 5) and which serves as a holder for the ball joint pin 52. A ball 53 surrounds the ball joint pin 52. The handlebar is provided with a spherical cap 53a, which surrounds the ball 53 and can be rotated relative to it in a known manner.

At the upper part of the rotating part 46, two parallel surfaces 54 are milled; as a counterpart to this, the jaw holder 55 has a slot 56, so that the jaw holder 55 engages over the two surfaces 54. This ensures the correct position of the jaw holder 55 relative to the rotating part 46 and the two parts are secured against relative rotation. As a connection between the rotating part 46 and the jaw holder 55, a clamping sleeve 57 is used, by means of which the rotating part 46 and the jaw holder 55 fixed, i. H. be connected torsionally rigid. For exact height adjustment of the jaw holder, an adjusting screw 58 is used, which is screwed into an eyelet 59 which is firmly connected to the clamping sleeve 57, and which can be rotated after loosening a locking nut 60 and a clamping screw 61, and thereby the height of the stop 62 on the jaw holder 55 is molded, adjusted. The pliers jaw 63, which is used to hold the blank 64, is screwed onto the pliers jaw carrier with a screw 65, and corresponding guide surfaces ensure the correct position.

The upper half of the pliers is constructed in principle the same as the lower, but has the difference that it is in the axial, ie. H. is supported in the vertical direction. Therefore, the upper jaw holder 66 with a sleeve 67, which is only coupled to the rotating part 68 with a clamp connection, is mounted in a sleeve 69 so as to be longitudinally displaceable. A spring 70, which is guided in a central bore of the jaw holder, presses it and thus the jaw 71 onto the blank 64. The spring travel X is set by turning a screw 72 after loosening a locking nut 73. In order to prevent the spring from springing out when the jaw holder 66 is removed, a cross pin 96 is installed at the upper end of the jaw holder 66. The attachment to the upper jaw holder is the same as below, as is the rotary drive.

So that there is space between the die holder 2 and the lower pliers box support 7b for the rotary drive 23a / 23b, the die holder 2 must be provided with a recess 74 in the area of the 1st die (FIGS. 1 and 4).

5 shows, using a vertical section, the fixed bearing of the lower spatial two-stroke rotary drive. A console 75 is screwed to the die holder 2 at the bottom. With this console 75, which serves as an assembly aid, a holding plate 76 is detachably connected. A bearing journal 77 is rigidly connected to this holding plate 76. The link 24 provided with a bearing bush 78 is placed over the bearing pin 77 and secured with a cover 79 screwed onto the bearing pin 77. In order to prevent the ingress of dirt, the bearing bush 78 is provided with a seal 80 at the top, while the bearing is closed at the bottom with a cover 81. This mounting allows the handlebar 24 to rotate about the axis 28 (Fig. 2). At the other end of the link 24, the ball joint can be seen, which has already been described in FIG. 4. It can be seen here how the ball joint pin 52 is fastened to the housing 51 with a conical pin 82, which is firmly connected to the coupling 25.

The upper fixed bearing is mounted on a bracket 26 (Fig. 1). This is pressed onto the die holder cover 3 by a hydraulically actuated cylinder 27, which at the same time serves to pivot the upper tong holder box 7a, and is thus held stationary.

In this device, it is a condition that when the blank has been pushed into the 1st station up to the stop 18 (FIG. 1), its center or center of gravity is located in the axis of rotation 21 of the pair of pliers 9. This means that if the section length is changed during the shearing process, the depth of penetration into the 1st station must also change. H. the stop 18 must be adjusted. If the section is shortened by dimension a, the stop must be moved forward by dimension a / 2. According to the present example, the stop 18 is mechanically or electrically coupled to the section length adjustment so that the position of the stop 18 always corresponds to the section length and the center of gravity of the blank is always the same distance from the front of the die as the axis of rotation 21 of the rotating device 9.

Fig. 3 shows the sequence of movements of the rotating blank. When the transverse transport device is in the starting position, the blank 83 lies against the stop pin 18, which in one instead of the normal forming insert 84 inserted into the opening provided for this purpose. When the transverse transport movement begins, the blank is also started to be turned immediately. The filler 84 is set back from the normal die front edge to leave room for the long blank. It can be seen from the figure that the rotating blank 85 would collide with the die holder 2. A recess 86 is therefore arranged there. The die 87 inserted in the second station also has a small adjustment 88. This adjustment 88 can be kept so low because the blank, because of the choice of the spatial two-stroke as a rotary drive and because of the geometrical arrangement of the joints, before going through half the translational stroke by much more than 45 °, in the present example by about 60 °, is rotated. As a result, the die 87 experiences practically no restriction and is therefore a fully-fledged forming die.

In order to obtain good accessibility when working on the tool space, the upper tong holder box 7a can be swung up around the shaft 8 (FIG. 1). For this purpose, the shaft 8 is uncoupled from the drive mechanism, not shown, and pushed beyond the left starting position (1st pliers before 1st die) until the projecting profile piece 90, which is a continuation of the shaft 92, on which the bearing bracket 26 is attached, and which in is mounted on the same axis 93 as shaft 8, projects into the matching opening 91. Then the upper tong holder box 7a can be pivoted up with the cylinder 27. The bearing bracket 26 rotates with it, including the rotary drive 23. Thus, the upper tong support box 7a can be pivoted up without problems.

For the conversion to normal forming, d. H. without rotating the blank, the rotatable device 9 can be replaced by an original pair of pliers (version 10, 11, Fig. 1). The rotary drive 23 remains on the pliers units, i.e. H. the upper one is separated from the bearing bracket 26 by loosening the screws 95, while the lower rotary drive is separated from the guide device by loosening the screws 95 (FIG. 5). This ensures a quick changeover for forming conventional parts.

In the exemplary embodiment described above, a holding station I was switched on between the shearing station and the first forming station II, the main function of which is to hold the sheared section until it has been gripped securely by the pliers 19 and 20. However, it would be entirely possible to carry out forming in station I. The turning device described could also very generally between any two neighboring stations, for. B. between the forming stations 111 and IV, are attached.

The exemplary embodiment shows a multi-stage forming machine with horizontal press ram movement. The principle claimed can also be applied equally to vertical machines.

According to a preferred embodiment of the invention, both pliers 19 and 20 (FIG. 1) are coupled to a guide gear 23. But it would also be possible to inevitably guide only one pair of pliers over such a guide gear and to arrange the other loosely rotatable.

Claims (8)

1. A multistage forming machine for the forming of blanks without cuttings which are turned through practically 90° during their conveyance by means of a transverse conveyor device between two adjoining working stations of the forming machine, one blank being transposed from an initial position extending in the direction of the longitudinal axis of the blank and planned to be parallel to the first working station (1), into a position planned to be transverse to the axis of the blank ahead of the second working station (11), with a gripper pair (9) provided on the transverse conveyor device for these working stations, witt? upper and lower grippers (19, 20) gripping the blank along its length, which are carried by gripper carrier (9a, 9b) rigidly arranged in mutually opposed bearings (22a, 22b) at the front sides of upper and lower gripper carrier boxes (7a, 7b) of the transverse conveyor device for rotation around a common axis (21) extending transversely to the pressing direction and to the longitudinal axis of the blank, this axis (21) also passing through its centre of displacement when the blank is gripped by the grippers and which in the transverse transport can be moved forward and backward in a straight line between the working stations, furthermore with a transfer element (9d, 9c, 46) engaging with at least one gripper carrier (9a, 9b) rigidly for rotation and displacement therewith relative to the axis (21), whereon there engages one end of a rotation guidance mechanism (23) whose other end is supported on a fixed anchorage fixed with respect to the gripper carrier which is moved forward and backward during the transverse transport, characterised in that the rotation guidance mechanism (23) is a two-stroke mechanism (23a, 23b) movable in three dimensions which encompasses a guide means (24) arranged with one end on the anchorage disposed between the said working stations (I, II) for displacement around a swivelling axis (28) parallel to the axis (21), projecting from the swivelling axis (28) radially outwards, depending on the position of the transverse conveyor device towards the main axis of the first working station (I) or towards the straight transverse conveyance path (32), and which carries at its other end a part of a jointed coupling (30, 53), furthermore a coupler (25) carrying at one end the other part of the jointed coupling, connected via this component with that of the coupler (25), extending with respect to the guide means at an angle towards the transfer element (9d, 9c, 46) and being there mounted by means of a joint pin (50) for deflection around a swivelling axis (29a, 29b) extending perpendicular through the axis (21) and wherein the guide means (24) is connected with the coupler (25) via the jointed coupling for swivelling around a common axis (30) lying at their point of intersection and extending substantially in the same direction as the axis (21) and the swivelling axis (28), and (that) the jointed coupling has, furthermore a joint guidance sector (53, 53a) which allows, additionally to the scope for swivelling, a limited tilting movement between the guide means and the coupler with respect to the joint axis (30) corresponding to the displacement path of the transfer element (9d, 9c, 46) during the opening and closing of the grippers (19, 20), the dimensioning of the two stroke mechanism (23a, 23b) being effected in such a way that the grippers (19, 20) holding the blank are rotated through larger angular units at the start of the translational movement than in the last stage of the translation.

2. A forming machine according to Claim 1, characterised in that the jointed coupling (53) disposed between the coupler (25) and the guide means (24) is a ball and socket joint.

3. A forming machine according to one of claims 1 or 2, characterised in that the coupler (25) is fork shaped at the end facing towards the transfer element (9c, 9d, 46) and does, therewith, encompass a pin (50) passing through the transfer element (46), whilst the other end of the coupler (25) forms a housing (51) whose pin (52) is enveloped by the guide means means (24) via the ball and socket joint (53).

4. A forming machine according to Claim 3, characterised in that the coupler (25) is only connected to the pin (50) on one side.

5. A forming machine according to one of claims 1 to 4, characterised in that the gripper carrier (9a, 9b, 55) is conjugately coupled with the adjoining transfer element (46) in such a way that their mutual distance may be altered by means of an adjusting element (58), one gripper carrier (55) respectively of each gripper pair being capable of being fixed in its respective position in the direction of its gripping movement in relation to the transfer element (46), whilst the other gripper carrier (66) is spring mounted (at) (70) in the direction of its gripping movement.

6. A forming machine according to one of claims 1 to 5, with a horizontal forming direction, characterised in that the upper guide mechanism (23a) is fixed on a bracket (26) which is swivel mounted on a shaft (92) which may, in turn, be coupled with the main shaft (8) via a detachable coupling (90) in such a way that the whole gripper carrier apparatus (7a) including the upper guide mechanism (23a) may be tilted upwards around the main shaft (8) by a drive element (27) engaging on the bracket (26).

7. A forming machine according to one of Claims 1 to 6, wherein the rotation is to be effected ahead of the first forming station, characterised in that there is interposed between the shearing station (15) and the first forming station (II), a holding station (I), wherein the blank (17) is held between a stop pin (18) and a movable holding pin (16).

8. A forming machine according to Claim 7, wherein the stop (18) is mounted for displacement in the longitudinal direction and is designed to be adjustable with a view to the processing of blanks of various lengths, characterised in that the length adjustment on the shearing mechanism (15) is coupled with the adjustment device of the stop (18) in such a way that in a transition to a blank of a different length, the stop (18) automatically adjusts to the latter.

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