EP0011293A1 - Device for cutting off a blank from bar stock and feeding the blank to the pressing tools of a doubly acting press - Google Patents

Abstract

This device has a shearing cutter (20) which can be moved in a plane transverse to the feed direction of a continuous piece (16) of material and the motion of which, when in the form of a disc (24), is effected, for instance, by rotation about a pivot (25) or, when in the form of a bar, by a corresponding displacement, and a transporter (21) which is actuated, for instance, by a rocker (44) and can be moved in synchrony with the press between two end positions. A die-set comprising a fixed and a movable tool is arranged on both sides of the feed for the continuous piece (16) of material, and in each of the end positions of the transporter (21), the said transporter simultaneously picks up a blank (22) and delivers another blank (22) to one of the die-sets. For the purpose of simple and safe transport of the blank (22), the shearing cutter (20) has two cutting bushes (26) which, during its movement, can be moved alternately by a distance equal to the spacing between the two cutting bushes (26), out of a position of introduction for the continuous piece (16) of material into an ejection position for the sheared blank (22). The sheared blank (22) taken along during this process into the ejection position can then be transferred, for instance by means of an ejector (33), to the transporter (21), situated in one of its end positions. <IMAGE>

Description

The invention relates to a device for separating a blank from a strand of material or the like. by means of a shearing knife movable in a plane transverse to the strand feed and feeding the separated blank to alternately one of two press molds of a double press arranged on both sides of the material feed, the conveyor being movable between two end positions in the work cycle of the press and simultaneously receiving a blank and one in each end position passes another blank to a mold made of a machine tool and a movable tool.

Double presses of this type are known (DE-OS 2 405 530, 2 531 760). In one case, the shearing knife feeds the compact, separated from the endless strand of material, alternately to one of two molds. In the other case, in addition to the shearing knife, a separate conveyor is arranged, which takes over the compact separated from the strand of material by advancing the strand of material immediately before the knife opening. However, it has been shown that the material feed is imperfect, possibly due to slippage of the feed device, and the compact does not have the required size. This generally leads to a blockage of the press. The object of the invention is to remedy this deficiency. For Solve this problem, it makes use of the idea that _A bscherposition of the compact of the material strand and the position in which the separated compact is taken over by the carrier, spatially separate, without requiring, however, additional components are required, which increase the cost of the press and their Workflow would complicate.

Based on this general idea, the invention provides in a device of the type mentioned at the outset that the shearing knife has two cutting bushes, each of which, alternately by the distance between the two cutting bushings, from the insertion position for the strand of material into an ejection position for the sheared blank for transfer is movably arranged on the transporter located in its one end position.

Since the shearing knife is movable anyway, the invention also uses this movement to transfer the separated compact to a transfer point located at a short distance from the transporter, which then takes over the task of feeding to the press tool. By the simple measure of doubling the shear bushing or the like. the knife, a trouble-free workflow of such a double press can be accomplished in this way. This can significantly increase the performance and reliability of such a press. On the other hand, operating and maintenance personnel can be saved, since the separation of the shear position and the take-over position by the transporter according to the invention leads to a trouble-free workflow.

In a further development of the general idea of the invention, according to another feature, in a special embodiment of the device, the knife is rotatably mounted in cycles, and an ejection position is provided in which the separated blank is transferred to the transporter. The knife is ejected in this Case at the same time as the strand of material is inserted into the other cutting bush of the shearing knife.

It is within the scope of the invention to arrange the ejection position offset by 180 ° to the insertion position. Of course, any other angular range can also be selected that sufficiently separates the two positions. Depending on the requirements, the knife can be rotated back and forth in the opposite direction by 180 °. However, it is also within the scope of the invention to move the knife around the desired angular range, e.g. 180 °, can be rotated in the same direction. Which embodiment is preferred depends on the circumstances of the individual case and in particular the circumstances of the derivation of the knife drive from the drive of the press.

Another alternative is provided by the invention in such a way that the knife is mounted such that it can be moved back and forth in a manner known per se and has two ejection positions, one on each side of the insertion position. With this arrangement, the knife, which can be moved back and forth on a straight line or a curved path, performs a limited movement between the supplied strand of material and the transfer position to the transporter, which carries out the further transport to the press tool.

It is particularly advantageous that in each ejection position of this reciprocating knife an ejection ram moved in the press cycle is mounted in the press stand. Such an ejector solves the transfer of the blank from the knife to the transporter in a particularly simple and trouble-free manner.

In a further embodiment of the invention, a multiple tool can be arranged on the machine stand, which moves from a transfer position into a press position in the press cycle Working position relative to the movable tool and finally in an ejection position for the finished compact is rotatably mounted in its plane. This also spatially separates the individual work processes taking place in the area of the press tool, so that the performance of the press can be increased and the susceptibility to faults can be reduced.

Another alternative provides that a multiple tool is arranged on the machine stand, which is rotatably supported in the press cycle from a takeover position by the transporter into a working and ejection position for the finished compact in relation to the movable tool. In this alternative, the work process is broken down into two bars.

It is within the scope of the invention that a gear with intermittent movement, in particular a Maltese cross drive, is assigned to the rotatable tool, which in turn is expediently derived from the press drive for synchronization of the entire workflow.

With this design too, an ejection plunger which engages in the tool in the ejection position of the compact can be arranged in the machine stand.

• Fig. 1 einen Horizontalschnitt durch eine Ausführungsform einer Doppelpresse;
• Fig. 2 ein auszugsweise wiedergegebenes Detail einer Doppelpresse;
• Fig. 3 eine schematische Wiedergabe einer ersten Ausführungsform der Vorrichtung zum Abtrennen und Zuführen des Rohlings;
• Fig. 4 einen Schnitt etwa nach Linie IV - IV in Fig. 3;
• _Fig. 5 eine andere Ausführungsform dieser Vorrichtung im Horizontalschnitt und
• Fig. 6 ein Detail hieraus im Schnitt nach Linie VI - VI in Fig. 5;
• Fig. 7 eine Abwandlung der Ausführungsform nach Fig. 5 u. 6.

Further features, details and advantages of the invention will become apparent from the following description of some preferred embodiments and from the drawing. Here show:

• Figure 1 is a horizontal section through an embodiment of a double press.
• 2 shows a detail of a double press reproduced in part;
• Figure 3 is a schematic representation of a first embodiment of the device for separating and feeding the blank.
• 4 shows a section approximately along line IV-IV in FIG. 3;
• _F ig. 5 shows another embodiment of this device in horizontal section and
• 6 shows a detail of this in section along line VI-VI in FIG. 5;
• Fig. 7 shows a modification of the embodiment of Fig. 5 u. 6.

An embodiment of a double press is shown in FIG. 1 for a better understanding of the invention. A crankshaft 2 is mounted in the annularly closed stator 1 and is driven into rotation by the drive motor 4 via a V-belt drive 3. At the end of the shaft 2 opposite the V-belt pulley 5, a detachable flywheel 6 is provided. On the crank pin 8 of the opposing bends 9 u. 10 of the crankshaft 2 each engages a push rod 11, the other end of which is connected to one of two counter-rotating rockers 12. The rockers are mounted with the shaft 13 in the stand 1. They each carry a movable tool 14 which interacts with the fixed tool 15 mounted on the machine stand 1 to form a press mold. Such a press has twice the output compared to conventional presses at the same crankshaft speed. The pressing forces occur offset by 180 ° each.

The double press has only one material feed. The correspondingly profiled endless strand of material 16 is guided by the two pairs of rollers 17. The feed occurring in the working cycle of the double press is based on a further pair of rollers 18, which consists of at least one idling and one cyclically driven roller. A shearing knife 20 is mounted in the front transverse yoke 19 of the stand 1, to which a transporter 21 for the blanks 22 separated by the shearing knife 20 is connected in the feed direction of the material strand 16.

In the embodiment according to FIGS. 3 and 4, the shearing knife 20 consists of a disk 24 provided with external teeth 23, which by means of a stub shaft 25 in a bore 31 of the transverse yoke 19 is mounted and, offset from one another by 180 °, has two cutting bushes 26 which lie on the same radius. The disk 24 meshes with the gear 28 which is driven via the shaft 27 and is likewise mounted in the transverse yoke 19. The drive is, which is not shown in detail, appropriately derived from the press drive in a corresponding manner. It is carried out in cycles, namely in synchronism with the work of the press and the feed of the material strand 16. The cutting bushing 26, which is located at the top in FIGS Exit end to the cutter 20 has a counter-cutting tool 30. The length x of the part of the material strand 16 inserted into the shearing blade 24, which at the same time corresponds to the length of the blank 22 to be separated and pressed, is measured according to the drive of the feed rollers 18 and is not the subject of the present invention. 3 and 4 below the cutting bushing 26 in the disc 24 is aligned with a further bore 32 in the transverse yoke 19, in which an ejector pin 33 is mounted, which is used to eject the blank 22 separated from the material strand 16 by the shearing knife 20 from the Cutting bushing 26 of the cutting knife 20 is used. The drive of this ejector 33 is also expediently derived from the press drive and is necessarily matched to the work cycle of the press.

3 and 4, the shearing knife 20 consists of a rotatable disc 24, the embodiment according to FIGS. 5 and 6 has a back and forth in a recess 34 of the transverse yoke 19 of the stand 1 in the direction of the arrow 35 mounted cutter bar 36. This cutter bar 36 is also provided with two cutting bushings 26, the spacing of which corresponds to the spacing of the bore 29 for feeding the material strand 16 from one bore 32 each, which each receive an ejector pin 33. These work alternately and bump the blade bar 36 in the direction of arrow 35 blank 22 separated from the material strand 16 from the respective cutting bush 26. The knife bar 36 is driven by an angle lever 39 which is pivotably pivoted about the pin 37 in the direction of arrow 38 and which is driven via a push rod 40 by an eccentric 41, which in turn derives its synchronous drive from the press drive. The head 42 engages in a recess 43 of the cutter bar 34 and takes it with it as it moves. The analogous relationships are present in the embodiment according to FIG. 7, so that there is no need to go into this in detail with regard to the separation of the blank from the material strand 16.

The transporter 21 takes over the blank 22 ejected from the shearing knife 20 and transfers it to the press mold, which consists of a movable tool 14 and a fixed tool 15. For this purpose, a rocker 44 mounted in a manner not shown in detail on the stand 1 with two pliers-like grippers 45 is used. These move in the direction of the arrow 46 on the circular movement path 47, one gripper 45 being aligned with the press mold at the reversal points of the movement path. In this case, the rocker 44 moves into the space between the movable and stationary tool 1.4, 15 with the mold open. Appropriate drive synchronization means that the respective blank 22 is taken over by the tools 14, 15 and the subsequent pressing process is not affected by the transporter 21.

The stationary tool 15 can, as is the case with the embodiment according to FIG. 7, each be a simple tool which is arranged in the transverse yoke 19 of the press stand 1. In this embodiment, for example, a blank 22 is pressed into a ball 47, as may be used for the manufacture of ball bearings. In the embodiment according to FIGS. 5 and 6, on the other hand, a tool carrier 49, which can be rotated about an axis 48, is mounted in a recess 50 of the yoke 19 on both sides, namely at the same distance from the material feed. The disc-shaped work Tool carrier 49 has a ring gear 51 which meshes with a gear 52 which is mounted on the shaft 53 and is fixedly connected to a Maltese cross 54. This in turn is in engagement with a crank pin 55 of a crank 56, which expediently rotates continuously in the derivation of the press drive, so that the tool carrier 49 undergoes an intermittent rotational movement about the axis 48. In the embodiment shown, the tool carrier 49 has three tools 15, which are arranged at an angle of 120 ° on the same circular arc of the tool carrier 49. In this embodiment, the transfer position for the blank 22 by the transporter 21 can be separated from the subsequent working position in which the blank 22 is pressed and from a subsequent ejection position by 120 °. Of course, another design is also possible, namely the pressing process takes place in the position of the tool carrier 49, in which the blank 22 is transferred by the transporter 21 (see FIGS. 5 and 6). An ejector 58 is used to eject the finished workpiece 57, which is mounted in a bore 59 of the transverse yoke 19 so as to be longitudinally displaceable in the work cycle of the press.

Of course, the blank 22 picked up by the transporter 21 in the transition position can be gradually pressed into the rotatably arranged tool carrier 49 in the successive standstill positions. After the last deformation process, the finished workpiece is ejected by means of the ejector 58. For this purpose, the tool 14 must be equipped with two or more molds, which coincide with the positions of the tools 15.

Claims (12)

1. Device for separating a blank from a strand of material or the like. by means of a shearing knife movable in a plane transverse to the strand feed and feeding the separated blank to alternately one of two press molds arranged on both sides of the material feed in a double press, the conveyor being movable between two end positions in the work cycle of the press and simultaneously receiving a blank in each end position and transfers another blank to a press mold from a tool arranged on the machine stand and a movable tool, characterized in that the shearing knife (20) has two cutting bushes (26), each of which alternately by the distance between the two cutting bushes (26) from the insertion position for the strand of material (16) is movably arranged in an ejection position for the sheared blank (22) for transfer to the transporter (21) in its one end position. 2. Apparatus according to claim 1, characterized in that the Abschermesser (20) is rotatably mounted cyclically and at least one ejection position is provided. 3. Apparatus according to claim 2, characterized in that the ejection position of the rotatable knife (20) is arranged offset by 180 ° to the insertion position. 4. The device according to claim 2, characterized in that the shearing knife (20) is rotatably arranged in opposite directions back and forth by 180 °. 5. The device according to claim 2, characterized in that the shearing knife (20) is arranged rotatable in the same direction by 180 °. 6. The device according to claim 1, characterized in that the shearing knife (20) in a manner known per se forth movably and has two ejection positions, one on each side of the insertion position. 7. Device according to one of claims 1 to 4, characterized in that an ejector pin (33) moved in the press cycle is arranged in the press stand in each ejection position. 8. Device according to one of claims 1 to 7, characterized in that a multiple tool is arranged on the machine stand (1), which in the press cycle from a takeover position for the blank (22) from the transporter (21) into a working position with respect to the movable tool ( 14) and is rotatably mounted in an ejection position for the finished compact (57) in its plane. 9. Device according to one of claims 1 to 7, characterized in that the tool consists of a multiple tool (49) which in the press cycle from a takeover position for the blank (22) from the transporter (21) in a common working position relative to the movable tool (14) and ejection position for the finished compact (57) is rotatably mounted in its plane. 10. Device according to one of claims 1 to 7, characterized in that the arranged on the machine stand (1) tool (15) consists of a multiple tool (40), the press cycle from a common takeover position for the blank (22) from the transporter ( 21) and at the same time the working position relative to the movable tool (14) is rotatably mounted in its eject position for the finished compact (57). 11. The device according to claim 8 to 10, characterized in that the rotatable multiple tool (49) is associated with a gear with intermittent movement, in particular a Maltese cross drive (54). 12. The apparatus of claim 8 to 10, characterized in that in the machine stand (1) in the ejection position in the multiple tool (49) engaging ejector pin (58) is arranged.

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