EP1340562A2 - Ejector mechanism on the punch-side of a single or multi stage press - Google Patents

Abstract

A blocking mechanism fixed to the press frame blocks an ejector pin (64) when the press carriage (12) returns from a pressing position. The blocking mechanism has a positionally adjustable blocking piece, which may be retracted into blocking engagement with the ejector pin while the pin contacts a stop (68). The activation of the blocking mechanism and resetting unit are program controlled. The ejector pin protrudes from a press ram (56) when assuming an extended position wherein end of the pin remote from the stationary press die (80) is distanced from the stop.

Description

The invention relates to a stamp-side ejection device for workpieces in one or Multi-stage presses, one on a press frame between one against one stationary press matrix extended press position and an end position remote from this have movable press slide with a press die, with the stationary press die cooperates, further with a guided in the pressing direction on the press slide, the Press punch penetrating ejector pin, which is between a retracted end position, in which he with his distal end against one on the press slide trained stop supports, and one protruding from the press ram Extended position in which its end remote from the die is at a distance from the stop, is displaceable and is provided with a resetting device which is against it Extending direction acts, and by means of a blocking device fixed to the press frame Return of the press slide from its pressing position against the return movement of the Press carriage can be releasably blocked, the activation or deactivation of the Blocking device and the activation of the reset device program-controlled and are coupled together.

Such ejection devices are used for ejecting workpieces on the die side at the die Multi-stage presses, such as workpieces in particular screws, bolts, Rivets or similar parts come into question. The ejection process is in the cycle of Integrated press operation.

Devices for producing a stamp-side ejection movement have been around for a long time after the pressing process to release and eject the workpieces from the tools, e.g. known from hexagon head punches on automatic forming presses. Doing so Movement from the outside, either from the press frame (e.g. DE 24 50 631 C) or from the crankshaft (e.g. DE 1 750 033 C), in the press slide of the forming press initiated, then via cams, angle levers or other transmission elements the desired ejection movement is generated. A disadvantage of these known ejection systems is, however, that they are often provided with many joints, levers, gears or the like and have a significant mass that must be moved with the press slide and thereby being excited to vibrate. In addition, these known ejection systems also have a certain deflection, which is responsible for the fact that the workpiece is first out The stationary die of the forming press releases before it moves out of the die is solved, which can lead to a loss of the workpiece before it, for example from the Gripper fingers of a transfer device of the press, can be safely accepted. Another disadvantage is that with changing law of motion of the press slide, about with a changed slide stroke, also the motion law of the ejector on the stamp cumbersome to change, the ejection stroke usually only with great effort is changeable.

In the known ejection systems, an overload protection is usually a break protection provided, which must be renewed after their triggering.

From DE 100 07 255 A a stamp-side ejection device is also known from which means the ejector pin penetrating the stamp at its end remote from the die an ejector lever can be acted upon, the end of the ejector lever, which the End of the ejector pin is applied between the latter and a stop on the press slide is interposed and always at the far end of the ejector pin is present, even if the press slide is returned after the pressing process. At the The ejector lever is retracted by means of a toggle lever connection and a switchable electromagnet fixed in place on the frame, so that when Retraction of the press slide through it the ejector lever for the ejection movement from the Press stamp is pushed out. Only when the desired ejection movement by the Ejector pin is executed, i.e. it is in the full, desired extended position, is blocked by the ejector lever in its housing-fixed position Deactivated the electromagnet. At the same time, the reset device activated, through which the ejector lever is retracted into the press slide and thus at the same time the end of the ejector pin against the end remote from the die Tilt the adjacent ejector lever until it is against the fixed stop Facility is coming. This return movement of the ejector lever is also supported by a spring that biases him in this direction.

The toggle lever connection of the ejector lever pivotally mounted on the press frame can also be used as an overload protection, which then protects the forming press responds when the force with which the workpiece is removed from the punch by means of the ejector pin must be pressed, for example if the tool breaks, exceeds a set dimension. Then kinks the toggle lever system because the programmable holding force of the Electromagnet is exceeded, which is due to the program control of the forming press recognized immediately and the press can be stopped immediately. The previously known Ejector systems, therefore, do not need to renew the break protection system.

By the programmable selection of the switch-off time of the energization of the Electromagnets during the retraction of the press slide can be known in this Ejection device the time period of the ejector pin and thus the Ejector stroke can be easily specified, so that each ejector pin Multi-stage presses can be set individually using the press program control. The cumbersome change required in previous ejector systems Movement law for the stamp-side ejector in a changing The law of motion of the press slide has thus been eliminated.

Even though this known ejector device has already presented significant problems known ejectors solves in an excellent manner, it is used by the Ejector lever and its toggle link with the electromagnet locking mechanism on the press frame still with relatively large masses of the system affected and therefore not for higher working speeds of the press (about 50 Pressing processes per minute) can be used.

Proceeding from this, the invention is therefore based on the object Eject device to improve such that the total mass of the ejector system is still can be further reduced and in particular use even with larger ones Press speeds in the range of over 50 press strokes per minute are possible.

According to the invention, this object is achieved with a stamp-side ejection device Type mentioned above solved in that the blocking device is a variable position Blocking element comprises, which in the pressing position of the press slide in one blocking engagement with the ejector pin or a part connected to it can be retracted while the ejector pin is in contact with the stop located.

The invention provides a stamp-side ejection device in which of the generic device, the blocking device is no longer in constant contact with the ejector pin must be held and blocked at a certain point. Rather, according to the invention, the position of the blocking device is changed Blocking element of the same used, that only when the press slide in his Press position is brought into blocking engagement with the ejector pin (or one with this connected part) is retracted or moved while the ejector pin is still in contact with the housing-fixed stop. So that the on Ejector pin in its longitudinal direction as a result of the pressing process safely over force the system of the ejector pin against the stop on the press slide without Interposition of the blocking element are supported, the latter only in the The moment when the blocking effect is desired, in blocking engagement with the Ejector pin (or a part of this) brought and thus the locking directly on Ejector pin (or the part connected to it) can be made if this has reached its ejection position. Different from the generic device finds a movement of the blocking device in the invention, which is caused by movement of the press carriage is no longer triggered, which means that even with fast carriage movements, So with high press cycles, so far no co-movement of the Blocking device occurs. In the invention, the blocking device is used solely for the Ejector pin during the return of the press slide (or only part of it Return movement) to block relative to the press frame and thereby the To cause the ejector pin to extend. If this is achieved, the Blocking device again moved out of blocking intervention and is thus also with the other Return movement of the press slide is not involved in the moving masses. So that falls Blocking device as a moving mass in a process of sliding completely away with the Advantage that it does not vibrate. The adjustment movements that the Blocking device are required to get this into and out of this blocking position Lead out blocking position can be set comparatively small, so that also in this respect a quick execution of these adjustment movements at high Press speeds can be easily realized.

In the press according to the invention, the blocking device can also be so without difficulty train that their release when a certain predetermined force is exceeded in Longitudinal direction of the trigger pin is positively forced, so that thereby a wear-free overload protection can be achieved. A change in Ejection length of the ejector stroke is through the program control of the blocking device in the With regard to the duration of the blocking effect, it is also easy to carry out and therefore easy to different laws of motion z. B. a multi-stage press is adaptable.

The ejecting device on the stamp side according to the invention is particularly low in mass Ejection movement occurs regardless of the law of motion of the press slide and the Workpieces are also in the stationary tool (namely the Die) held.

In the ejection device according to the invention, it is particularly advantageous if that Blocking element is a molded part that is used to block the ejector pin against a complementary shaping can be applied to this or a part connected to it, such a form-locking blocking is so formed without difficulty can be that if an overload occurs, the blocking automatically positive is solved again. For this, it is particularly preferred for. B. the molding in the form of a Switching roller to be formed against a corresponding oblique contact surface on Ejector pin is pressed. This allows a given longitudinal force to occur in the longitudinal direction of the ejector pin (and effective in the blocking direction) corresponding adjustment of the pressure force of the control roller against the surface an automatic The blocking can be released easily.

A particularly preferred embodiment of the ejection device according to the invention will achieved in that the molded part is attached to a piston rod which is in a valve block slidably mounted and by means of a pressure fluid between an extended Blocked position and a retracted end position (which, for example, a whole or partial Retraction into the valve block), in which there is no blocking intervention, can be moved. Such a design of the blocking device, which works as a hydraulic double piston, the can be retracted and extended in the direction of travel, not only allows quick switching and Adjustment movements (forward and reverse), but also leads to relatively small moving masses and to a precisely adjustable (and adjustable) blocking effect.

The piston rod can be operated in any suitable way, but is very special preferably operated hydraulically.

A further advantageous embodiment of the ejection device according to the invention exists also in that the ejector pin at its end remote from the die with a piston rod (as "a part connected to it") is provided on which the shape for the blocking Engagement with the blocking element is attached. In this case, preference is given to the end remote from the die the piston rod on its side facing the blocking element has an inclined surface as Contact surface for the molded part attached. This results in an excellent function of Ejecting device according to the invention with only very little construction.

Advantageously, the ejection device according to the invention is further developed in that the ejector pin not only in its retracted position by means of the reset device can be retracted, but the reset device is also designed so that it can also be moved in its extension direction, which achieves the advantage that the ejector pin can also be used to e.g. B. a prefabricated workpiece in push the die in and hold it, then resiliently during the actual pressing process investigate if the reset device z. B. is operated by means of a compressed gas.

The blocking device, which is suitable regardless of the movement of the press slide Way must be fixed to the frame is in an ejection device according to the invention preferably designed so that they are in a saving in the press slide to close to Ejector pin or the part connected to it protrudes. This allows the advantage achieve that the blocking device for carrying out the blocking intervention only relatively small Extending movements for the blocking element must carry out what a rapid blocking (such also a quick release of the block) is permitted.

Fig. 1 eine teilweise geschnittene Seitenansicht einer erfindungsgemäßen stempelseitigen Auswerfeinrichtung in einer ersten Endstellung im hinteren Totpunkt des Preß-Schlittens, zu Beginn eines Preßzyklusses der Presse;

Fig. 2 die stempelseitige Auswerfeinrichtung aus Fig. 1 (wieder in teilweise geschnittener Seitenansicht), hier jedoch in einer zweiten, vorderen Endstellung unmittelbar vor Beginn eines Auswerfvorgangs (im vorderen Totpunkt des Preß-Schlittens);

Fig. 3 die stempelseitige Auswerfeinrichtung der Fig. 1 und 2, aber nach beendetem Auswerfvorgang, und

Fig. 4 die stempelseitige Auswerfeinrichtung gemäß den Fig. 1 bis 3, jedoch in dem Zustand, in dem der Auswerferstift wieder in seine in den Preß-Schlitten eingefahrene (hintere) Endstellung zurückgefahren ist.

The invention is explained in more detail below in principle by way of example with reference to the drawing. Show it:

Figure 1 is a partially sectioned side view of a stamp-side ejection device according to the invention in a first end position in the rear dead center of the press slide, at the beginning of a press cycle of the press.

FIG. 2 shows the ejection device on the die side from FIG. 1 (again in a partially sectioned side view), but here in a second, front end position immediately before the start of an ejection process (at the front dead center of the press slide);

3 shows the ejection device on the stamp of FIGS. 1 and 2, but after the ejection process has ended, and

Fig. 4, the stamp-side ejection device according to FIGS. 1 to 3, but in the state in which the ejector pin has moved back into its (rear) end position which has been inserted into the press slide.

In principle, a constructive arrangement for a stamp-side is shown in FIGS Ejector system shown, the individual figures, however, different positions show during a press cycle. The same in the different figures Provide components with the same reference numerals.

The structural details shown in the figures are only exemplary stamp-side ejection device 10 provides part of a single or multi-stage press a press slide which can be pushed back and forth in a press position (not shown) 12. The latter is used by means of forming tools (stamping) on the slide side. and stationary matrices from workpiece blanks, if necessary, gradually, finished To manufacture workpieces.

Furthermore, a valve block 14 is provided, which is placed on the press (not shown) is attached and consists of a lower part 16 and an upper part 18, which is fixed are screwed together and form a machine frame together.

In the lower valve block part 16 are a lower part 20 of a piston rod 22 and one with the Piston rod 22 firmly connected piston 24 slidably mounted. The glides Piston 24 in a cylinder bore 26, while the lower piston rod part 20 in a Guide bore 28 of the lower valve block part 16 is guided.

In the lower valve block part 16, a piston rod adjoins the piston 24 at the top 20 'and ends in a thickened end part 30, which is also in the upper valve block part 18 in a guide bore 32 is guided.

In the upper valve block part 18 there is also a plunger 34 designed as a piston in one Cylinder bore 36 slidably mounted and is located at the thickened end 30 of the Piston rod 22 on.

The valve block parts 16 and 18 are provided with hydraulic inlets and outlets 38 and 40, respectively open into the cylinder bores 26 and 36. At the lower valve block part 16 is also still a hydraulic valve 42 is attached.

The press slide 12 can be moved back and forth by a crankshaft 44 via push rods 46 and provided with an externally accessible recess 48 into which the tapered end of the protrudes lower valve block part 16.

The end protruding from the lower valve block part 16 of the valve block 14 Piston rod 20 is forked, with a switching roller 50 between its forks a bolt 52 is rotatably mounted.

At the front end of the press slide 12, a press die is seated in a holder 54 Press tool, in the embodiment shown in the form of a Hexagon head stamp 56, in its axial extension a collar bushing 58 in the press slide 12 is attached.

A piston rod 60 is slidably slidable in the collar 58. The matrix-close, thickened end of this piston rod 60 serves as a piston with which a coaxial ejector pin 64 is connected, which is slidable in the press carriage 12 and in the hexagonal die 56 is stored. The piston 62 slides in a cylinder bore 66 of the press slide 12, which also receives the flange of the flange bushing 58 at the end.

The cylinder bore 66 and the piston 62 form a pneumatic unit as part of one Device for resetting the ejector pin 64. The piston rod 60 lies with her End away from the die at a stop 68 which is attached to the press slide 12 and into the Recess 48 protrudes.

The annular end face of the piston rod 60, which also projects into the recess 48 to the stop 68 on its side facing the switching roller 50 with a bevel 70 provided that serves as switching cams in interaction with the switching roller 50, as this continues is described in more detail below.

The press slide 12 is also provided with two compressed air supply and exhaust air lines 72 and 74, which open into the cylinder bore 66 and to the return device for the ejector pin 64 belong.

The mode of operation of the arrangement of a stamp-side ejection device shown will now be described:
The description is based on the state according to FIG. 1, in which the press slide 12 is in its rear dead center (that is to say remote from the die) before the start of a pressing and forming process. Here are the piston rod 22 (consisting of the piston rod part 20 with attached switching roller 50, the part 20 'and the thickened end part 30), the piston 24 and the plunger 34, which stand here with their axis approximately centrally and vertically above the piston rod 60 , moved hydraulically to their rear end position (retracted end position). The ejector pin 64 and the pneumatic unit (consisting of piston rod 60 and piston 62) are also brought as a one-piece unit into their rear position (away from the die) and the end of the piston rod 60 lies directly against the stop 68 of the press slide 12 with its end remote from the die.
During a forward movement (in the drawing, therefore: to the left) of the press slide 12 driven by the crankshaft 44, the hexagon head punch 56, which is seated in the holder 54 at the front end of the press slide 12, pushes in (e.g. of one, approximately Partly machined workpiece 76 (FIG. 1) provided in a die 80 and fixedly known from DE 40 02 347 A1, transfer device of the progressively working forming machine or multi-stage press for transferring a partially machined workpiece from one station to the subsequent station for the further machining operation) further forms this workpiece 76, a hexagon head of an emerging screw 76 '(FIGS. 3 and 4) being formed, corresponding to the press ram 56.

The ejector pin is located in the front dead center of the press slide 12 (as shown in FIG. 2) 64 with the piston 62 and the piston rod 60 still at the stop 68 of the press slide 12 on. When the punch 56 hits the workpiece 76, the forming force z. T. on the ejector pin 64, the piston 62, the piston rod 60 and the stop 68 in the press slide 12 initiated.

In this manufacturing section, the workpiece 76 'is in the tools (namely die 80 and hexagon head punches 56) fully formed, d. H. here with the desired hexagon head Mistake. Due to the pressing process, the finished workpiece 76 'sits with the molded one Hexagon head fixed in stamp 56.

Shortly before the front dead center is exceeded, the program control of the switches Form the hydraulic valve 42. Now the plunger 34 designed as a piston is over the Hydraulic line 40 is acted upon by hydraulic pressure, so that the plunger 34, which acts as a piston and the piston rod / piston unit consisting of parts 30, 20 ', 24 and 20 with the Move switching roller 50 to its front end position. The switching roller 50 is now on the switching cam 70 of the piston rod 60, as can be seen in FIG. 2.

In the subsequent retraction of the press slide 12 after crossing the front Dead center in its rear dead center is now the desired ejection of the stamp finished workpiece 76 '.

During the carriage return, the ejector pin 64 remains because of the blocking or Locking of the piston rod 60 by the switching roller 50 and the switching cam 70 of the Piston rod 60 in the (fixed) end position shown in FIG. 2. From the beginning of the rewind of the press slide 12 is the shaped workpiece 76 ', which with its two ends in the Recesses of the hexagon head die 56 and the die 80 protrude from the ejector pin 64 held in the stationary die 80 until the backward movement of the press slide 12 the molded hexagon head of the workpiece 76 'as a result of the relative movement between the hexagon head stamp 56 and the ejector pin 64 from the latter from the Press punch 56 has been pushed out completely (ejector pin 64 with piston rod 60 remains in relation to the press body).

The stop 68 of the press slide 12 is now at a distance from End of the piston rod 60 remote from the die (see FIG. 3).

Then the hydraulic valve 42 is again controlled by the control of the forming press programmably excited and now piston 24 is actuated via hydraulic line 38 Hydraulic pressure applied to the piston rod side, so that the piston 24 with the Piston rod parts 20 (including switching roller 50), 20 'and 30 and the plunger 34 back in their Drive the rear end position, which is also the starting position for a new work cycle.

During this time, the in the cylinder bore 66 of the press slide 12 and on it Piston rod 60 in the flange bushing 58 sliding piston 62 over the Compressed air connection 72 is supplied with compressed air under program control, which means that it is on the piston side acted upon and the piston rod 60 is moved back with the ejector pin 64 until the Piston rod 60 with its end remote from the die again in contact with the stop 68 of the Press carriage 12 arrives. The piston 62 and the piston rod 60 with the ejector pin follow the further movement of the press slide 12, so also go into hers Starting position back. Finally, the press slide 12 has its rear stop position (rear dead center) reached again, as can be seen in Fig. 1.

During this time, the workpiece 76 'just deformed was ejector on the die side ejected from die 80. When turning the Crankshaft 44 now begins a new work cycle.

Through the programmable selection of the switching time of the hydraulic inflow from the Hydraulic line 38 to the hydraulic line 40 in the valve block parts 16 and 18 via the Hydraulic valve 42 during the retraction of the press carriage 12 can the duration of The ejector pin 64 stops with the piston 62 and the piston rod 60 (i.e. the Time periods during which a movement of the ejector pin 64 in the return direction of the Press carriage 12 is blocked) and thus the ejector stroke can be determined or set. Accordingly, in the case of multi-stage presses, each ejector pin 64 can be moved individually via the Program control of the press can be set.

Now the piston 62 of the reset device described for the ejector pin 64 on the other hand, during a certain period in the program sequence of the forming press Pressurized with compressed air via the compressed air connection 74, that is to say on the piston rod side, can the ejector pin 64 even shifted in its extension direction and can be used, for. B. to insert and hold a prefabricated workpiece in the die 80 and then yield resiliently during the actual pressing process, whereupon again on the piston side Air supply is switched.

The hydraulic unit of the ejector device 10 described consists of the tappet 34, the piston 24, and the piston rod parts 20, 20 'and 30, and at the end of the Set the piston rod 20 of the rotatably mounted switching roller 50 and the slope of the switching cam 70 with non-positive locking is a releasable lock, which at the same time as Overload protection can be used, works without wear and is adjustable. The Overload protection responds to the protection of the forming press when the force with which Workpiece 76 'must be pressed out of the punch 56 by means of the ejector pin 64, z. B. due to tool breakage, a set dimension (maximum permissible force value) exceeds. In this case, the control roller with the piston rod part 20, the piston 24 as well as the piston rod parts 20 'and 30 and the plunger 34 against the hydraulic force which the acted area of the plunger 34 and the pressure of the hydraulic fluid from the Hydraulic line 40 originates from the switch cam 70 automatically and solve the non-positive blocking or locking because of the programmable holding force was exceeded. This is recognized by the program control of the forming press, whereupon the latter is stopped immediately. Once the cause of the overload in the system has been eliminated this is immediately ready for use again.

Claims (9)

Stamp-side ejection device for workpieces in single-stage or multi-stage presses, which has a press slide (12) with a press punch (56) which can be moved on a press frame between a press position extended to a stationary press die (80) and a rest position distant from it. have, which cooperates with the stationary press die (80), further with an ejector pin (64) which is guided in the press direction on the press slide (12) and penetrates the press punch (56) and which is between a retracted end position in which it is is supported with its end remote from the die against a stop (68) formed on the press slide (12), and an extended position protruding from the press die (56), in which its end remote from the die is at a distance from the stop (68), displaceable and is provided with a reset device which acts counter to its extension direction and which is fixed by means of a blocking device fixed to the press frame g can be releasably blocked when the press slide (12) returns from its press position against the return movement of the press slide (12), the activation or deactivation of the blocking device and the connection of the reset device being program-controlled and coupled, characterized in that the blocking device (22, 50) comprises a position-changing blocking element (50) which, in the pressed position of the press slide (12), can be inserted into a blocking engagement with the ejector pin (64) or a part connected to it, while the ejector pin is in the process of being moved (64) is in abutment against the stop (68). Ejector device according to claim 1, characterized in that the blocking element is a molded part (50) which can be applied to block the ejector pin (64) against a complementary shape (70) on it or on a part (60) connected to it. Ejecting device according to claim 2, characterized in that the molded part is a switching roller (50). Ejector device according to claim 2 or 3, characterized in that the molded part is fastened to a piston rod (22) which is mounted displaceably in a valve block (14) and by means of a pressure fluid between an extended blocking position and an end position retracted into the valve block (14), in which there is no blocking intervention, can be moved. Ejector device according to claim 4, characterized in that the piston rod (22) can be actuated hydraulically. Ejector device according to one of claims 1 to 5, characterized in that the ejector pin (64) is connected at its end remote from the die to a piston rod (60) to which the shape (70) for the blocking engagement with the blocking element (50) is attached , Ejector device according to claim 6, characterized in that on the end of the piston rod (60) remote from the die, on its side facing the blocking element (50), an inclined surface (70) is attached as a contact surface for the molded part (50). Ejector device according to one of claims 1 to 7, characterized in that the ejector pin (64) can also be adjusted in its extension direction by means of the resetting device. Ejector device according to one of claims 1 to 8, characterized in that the blocking device (22, 50) into a recess (48) in the press slide (12) up to close to the ejector pin (64) or the part (69) connected thereto protrudes.

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