EP0224792A1 - Tool-changing arrangement for a multistage metal-forming machine tool - Google Patents

Abstract

In the proposed tool changing device, the stamping tools (13) and the die tools (1) are each mounted in a stamping tool block (14) or die tool block (5) designed in the manner of an exchangeable magazine. On the two tool blocks there are clamping surfaces (29, 31) with which the stamping tool block (14) can be clamped to a stamp clamping device (30) attached to the press slide (22) and at the same time to the front of the press slide (22), during the Die tool block (5) can be clamped to a clamping plate (7) attached to the machine body (25). Hydraulically actuated centering elements (11a, b), which engage in the area of the clamping surfaces (29 and 31), are used for vertical and horizontal centering. The clamping takes place via hydraulically actuated clamping elements (6a, b). All clamping and centering elements for clamping the tool blocks (14 and 5) as well as all coupling clamping elements (35), which are used for the non-positive connection of the stamping tools (13) with the press slide (22), can be controlled from a central control panel.

Description

The invention relates to a tool change device according to the preamble of patent claim 1.

Such devices should, above all, enable the stamping and die tools to be replaced as quickly as possible in the tool room of a forming machine, so that the corresponding changeover times that require machine downtime can be kept as short as possible.

In known devices of this type, the tools are fastened in tool change brackets and in some cases have to be replaced individually and clamped within the tool space of the forming machine. This sometimes forceful work must be carried out within the often narrow tool space and in an uncomfortable position of the body, which makes it difficult to carry out a reliable, uniform clamping of all tool packages. In any case, a tool exchange, which takes place in a known manner, requires relatively long changeover times in which the machine has to stand still. A partial automation in known tool changing devices is that the loosening and tightening of the clamping screws is carried out by a device. However, since the actuation of all fastening elements by means of this device also takes a relatively long time, only a negligible time saving is achieved with this known partial automation.

From DE-OS 19 66 879 and US-PS 3 559 446 it is known to preset tools on this anvil and a platen for use in a forming machine on a holding device which bears an anvil in a certain position. Although this known device saves a certain amount of time compared to tool changing systems, the tools of which must be installed individually in the tool room, however, the device known from the documents mentioned requires an expensive adjustment and bracing of the known tool change holders during installation in the forming machine, so that by the known presetting of the tools on the anvil and the platen by means of the said holding device can only be achieved as a whole.

A further disadvantage with known tool changing devices and in particular also with the tool described in the above-mentioned documents is that the stamping and die tools are guided in the tool holders without tension. As a result, increased wear of these tool guides and setting of the tool parts occurs relatively frequently during operation, which results in increasing play between the tool holder and the machine body, which cannot be compensated for during operation. A resulting loosening of the bracing of the corresponding tool holder with the press slide or the machine body can often only be recognized when the interacting tools have already been damaged or even destroyed.

The object of the invention is to provide a tool changing device in which the tools for a rapid automatic or semi-automatic change can be prepared outside the tool space of the forming machine in a manner that can be expected of low-wear operation and can be used in the shortest possible time A central control system allows both the stamp and die tools to be exchanged easily and with reliable tool adjustment.

The achievement of this object is particularly defined in the characterizing features of claim 1. Further details emerge from the corresponding subordinate claims.

Due to the arrangement of the stamping and die tools according to the invention in the manner of changing magazines in tool blocks, these can be made ready for use outside the machine, so that the downtime of the machine required for the tool change alone takes the duration of the tool block exchange.

In the inventive method of clamping the die-side and die-side tool blocks, the clamping elements are located in the corresponding clamping parts on the press slide or machine body side and protrude from them only with piston head sections of the pressure-actuated piston-cylinder units; these head sections can be inserted into the T-slots which are recessed in the tool block to be replaced in each case perpendicular to the row of the respective tools, and the tool blocks can then be subjected to a corresponding pressure medium application of the clamping elements are clamped against the pressing surfaces on the machine body or on the press slide. The displacement of the piston head sections between a tool block release position, in which the block can be removed from the tool space vertically to the stroke direction of the press slide, and a position ready for use to fix the respective tool block, is carried out from a central command console via corresponding pressure medium control devices, preferably a hydraulic control. The piston-cylinder units can be designed as tandem cylinders to achieve high contact pressures in order to obtain smaller piston diameters.

In addition to the clamping elements, pressure medium-actuated centering elements also remain in the machine body or press slide-side clamping parts when the tool block is replaced, which can engage with suitable piston sections in the centering recesses provided on the clamping surface of the respective tool block. These centering elements can be operated from the central control console. Using a suitable pressure medium control device, preferably also a hydraulic control, the clamping of the tool blocks can be controlled by the clamping elements by moving the piston sections of the centering elements into the appropriate centering recesses so that the entire respective tool block is positioned correctly in the correct position during the clamping of the tool block becomes. The centering and adjustment accuracy achieved is so high that there is no need for separate alignment of punch and die-side tools with respect to one another in the horizontal and vertical directions.

In the tool changing device according to the invention, a punch clamping device is provided between the punch tool block and the press slide, each with coupling tensioning elements aligned with the longitudinal longitudinal axis of the punch, which produce a non-positive, play-free connection between the punch tools on the one hand and the press slide on the other. These coupling clamping elements capture the respective stamping tools at their rear end sections via a detachable bayonet connection arranged in the area of the stamping tool block separating plane and press these via a pressure piece between the press slide and the stamp end to the press slide front under pressure control. Due to the contact pressure generated on the press slide front in accordance with the applied pressure, any play on the stamping tools and between them and the press slide is excluded. The contact pressure of the stamping tools, which is maintained and possibly monitored during operation, against the press slide front ensures in every position of the machine parts concerned that there are contact conditions which cannot be achieved with conventional tool clamping devices. A deformation or setting of the loaded tool parts which occurs in conventional devices and which has an effect on the clamping force of the connecting elements is compensated in the device according to the invention by constant pressurizing of the stamping tools in question, or such wear phenomena cannot occur at all. It can thus be seen that the stamp clamping device of the tool changing device according to the invention makes a large contribution to reducing the wear of the entire tool. About one in print medium circuit of the stamp clamping device built-in pressure switch, the contact pressure of the clamping device can be monitored during operation or checked by a corresponding safety device, which stops the machine when the pressure falls below a predetermined minimum and indicates the type of fault.

• Fig. 1 eine perspektivische Teilansicht eines Matrizenwerkzeugblocks nach den Merkmalen der Erfin­dung, befestigt an einem Maschinenkörper,
• Fig. 2 eine perspektivische Teilansicht eines Stempelwerkzeugblocks, der frontseitig an einem Preß­schlitten angebracht ist,
• Fig. 3 eine schematische Schnittdarstellung einer Zentriereinrichtung,
• Fig. 4 eine schematische Schnittansicht einer Stempel-Verspanneinrichtung,
• Fig. 5a eine schematische Schnittdarstellung durch einen Matrizenwerkzeugblock der über eine Spannplatte am Maschinenkörper befestigt ist, bei einer Schnittführung durch die Längsmittelachse eines Matrizenwerkzeugs zur Verdeutlichung des quali­tativen Druckspannungsverlaufs unter Preßkraft,
• Fig. 5b eine schematische Darstellung entsprechend der in Fig. 5a zur Veranschaulichung des qualitativen Druckspannungsverlaufs unter Preßkraft bei herkömmli­chen, unter Verwendung eines Amboß aufgebauten Matrizen­werkzeugen, und
• Fig. 5aʹ und 5bʹ zeigen den entsprechenden Druckspan­nungsverlauf.

Further details and functional relationships result from the following description of an embodiment of the tool changing device according to the invention with reference to drawings. Show it:

• 1 is a partial perspective view of a die block according to the features of the invention, attached to a machine body,
• 2 is a partial perspective view of a stamping tool block which is attached to a press slide on the front,
• 3 shows a schematic sectional illustration of a centering device,
• 4 shows a schematic sectional view of a stamp clamping device,
• 5a is a schematic sectional view through a die block which is fastened to the machine body by means of a clamping plate, with a cut through the longitudinal central axis of a die tool to illustrate the qualitative compressive stress curve under pressing force,
• Fig. 5b is a schematic representation corresponding to that in Fig. 5a to illustrate the qualitative compressive stress curve under pressure in conventional, using an anvil die tools, and
• 5aʹ and 5bʹ show the corresponding compressive stress curve.

The die tool block 5 shown in Fig. 1 has a centering plate 2 which receives 33 die tools 1 supported circumferentially in receiving bores, so that an adjacent row of individual die tools is formed for successive forming steps. On the left end section of the centering plate 2 as shown in FIG. 1, a bar knife 8 is visible, which is used to cut off blanks to be machined in the tools. From the front of the tool block 5, individual clamping glasses 3 are placed on the die tools 1, which are each provided with four threaded bores formed at their corner areas. On the surface of the centering plate 2 facing away from the clamping glasses 3, an adapter plate 4 is attached, which supports the die tools 1 at its rear end. 5a that the adapter plate 4 forms a relatively large-area support for the die tools 1 in comparison with the illustration in FIG. 5b. From the rear of the adapter plate, four clamping screws 9 are used for each pair of spectacles 3, which clamp the entire die tool block into a ready-to-install tool unit, which has an overall low overall depth.

As can also be seen from FIG. 5a, the placement of the clamping screws 9 in the corner regions of the clamping glasses 3 permits the use of a shrink ring 10 which can be designed much shorter and without weakening threaded holes than was the case with the conventional die packs according to FIG. 5b. The possible enlargement of the die parts lying behind the die tools 1 in the die tool block 5 according to FIG. 5a leads to an overall favorable compressive stress curve within the die support, since larger receiving surfaces are available for absorbing the pressing forces than in the case of conventional die packages. The pressure force curve to be expected in each example is shown in FIGS. 5a and 5b by dash-dotted lines and indicated as 0̸a and 0̸b. This diameter designation relates to the respective pressure receiving part which is in direct contact with the relevant die package. Corresponding conclusions can be drawn from the diagrams of the compressive stress curves under pressing force given for the two figures, regarding the tool wear to be expected in each case or the material stress.

The machine body 25 schematically indicated in FIG. 1 carries a clamping plate 7 on the front, on which the die tool block 5 with its adapter plate 4 can be clamped to a clamping surface 31 which runs transversely with respect to the longitudinal center axes of the die. The entire assembled unit forms the tool change holder 28. In the example shown, five T-grooves 26b running perpendicular to the row of die tools 1 are recessed in the adapter plate 4 for clamping the tool block 5. Correspondingly shaped piston head sections 32b engage in these grooves 26b form hydraulically operated piston-cylinder units (clamping elements 6b). 1, two clamping elements 6b are provided in the clamping plate 7 for each groove 26b. From the drawing it can be seen that with released clamping elements 6b the tool block 5 can be removed from the clamping plate 7 at right angles to the axis of the row of die tools 1. A transport device (not shown) can be provided for the corresponding removal of a die tool block removed in this way. The tensioning elements 6b are connected to a central hydraulic arrangement, and their piston displacement can be controlled from a central control desk.

In addition to the advantage of the quick release of the die tool block 5 from the clamping plate 7 by corresponding actuation of the clamping elements 6b, their use offers the further advantage that wear that can never be completely eliminated and a play that arises between the die tool holder 5 and the clamping surface of the clamping plate 7 can already be compensated for by the clamping elements that are under pressure during operation. It can therefore be said that a constantly high contact pressure of the clamping elements 6b ensures that contact conditions are always created when the machine parts meet, which are comparable to those when the machine is new. It is also possible to install pressure switches in the hydraulic circuit supplying the tensioning elements 6b, in order to be able to control the contact pressure in this way or to be able to monitor them via a safety arrangement and to indicate the cause of a malfunction.

2, the stamping tools 13 are mounted in a stamping tool block 14 and guided in bushings 15. In a very similar manner to that of the die tool block, T-grooves 26a are cut out on a clamping surface 29 of this tool block 14, perpendicular to the row of stamping tools 13, in which correspondingly shaped piston head sections 32a of clamping elements 6a engage, which with their pressure medium-actuated piston-cylinder units in a platen 24 of a stamp clamping device 30 are accommodated. The stamping tool block 14 together with the stamp clamping device 30 forms the stamp-side tool change holder 27, which is located on the front of the press slide 22. The tensioning elements 6a are constructed in the same way as the tensioning elements 6b described above, including their pressure medium actuating device.

FIG. 2 shows a hydraulically actuated centering element 11a, which is provided in a corresponding manner between the clamping plate 7 and the adapter plate 4 in the die tool block 5 according to FIG. 1. Such a centering element is shown in detail in FIG. 3 and is used for centering the respective tool blocks 5 and 14 on their clamping surfaces in the vertical and horizontal direction during the clamping process. The centering element 11b visible in FIG. 3 is accommodated in the clamping plate 7 and has a hydraulically actuated piston, the piston section 34b of which is conically shaped in order to be able to engage in conical surfaces of centering recesses 12b in the adapter plate 4. These hydraulically actuated centering elements 11a and 11b are matched to the clamping action of the hydraulic clamping elements 6a and 6b, operated from the central control panel, so that an exact positioning takes place essentially simultaneously with the clamping. After loosening the hydraulic clamping elements 6a and 6b, the centering elements 11a and 11b can, if desired, be held in engagement with their centering recesses 12a and 12b until the respective tool block is to be displaced vertically, for example when exchanged, in order to prevent premature displacement of the to be able to safely prevent loosened tool blocks. At least two centering elements are required for each tool block.

According to FIG. 2, the stamp clamping device 30 has a row of coupling clamping elements 35 which are aligned with the respective longitudinal longitudinal center axes and which can produce a non-positive, play-free connection between the stamping tools 13 on the one hand and the press slide 22 on the other hand. The coupling clamping elements 35 are provided, as shown in FIG. 4, on the side of the clamping plate 24 facing the clamping surface, each with a bayonet connection 17, which has a connecting sleeve 36 on the clamping element side, which can be connected to a sleeve counterpart 37 provided on the rear end section of a stamping tool 13. Furthermore, each of the clamping elements 35 has a hollow piston 16, which is guided in a relatively displaceable manner under pressure medium control within the clamping plate 24 and accommodates a relatively displaceable pressure piece 19 in its inner region, which is vertically displaceable on the one hand at the rear end of the stamping tool 13 and on the other hand on a support surface 39 in the press slide 22 guided adjustment wedge 18 is present. If according to the illustration 4, the hollow piston 16 is displaced to the right via the pressure medium circuit 38 (hydraulic channels) in the direction of the double arrow shown, with the bayonet connection 17 closed, the stamping tool concerned is simultaneously displaced in this direction, as a result of which the tool 13 corresponds to the hydraulic pressure acting on the Hollow piston 16 acts, is pressed against the adjusting wedge 18 and thus against the front of the press slide 22. If the hydraulic pressure on the hollow piston 16 is maintained, virtually any play between the stamping tool and the press slide front is eliminated.

The adjustment wedge 18 visible in FIG. 4 is used for the axial adjustment of the stamping tools. For this purpose, the hollow piston 16 must be made pressure-free so that the pressure piece 19 can be displaced in its interior depending on the vertical adjustment of the wedge 18. For remote actuation of the wedge adjustment, a motor drive 23 is shown schematically in FIG. 4, which can carry out a desired vertical displacement of the adjustment wedge 18 via a threaded spindle. The control of this drive 23 can also be operated from the central control panel. After the axial setting of the stamping tool 13 has been carried out, the hollow piston can be pressurized again in the manner described in order to achieve the axial bracing. A pressure switch can also be installed in the pressure medium circuit 38 of the hollow piston 16 in order to be able to monitor the clamping pressure of the hollow piston.

In addition to the loosening of the clamping elements 6a already described, the bayonet connection 17 is also necessary for replacing the stamping tool block 14 to open between the respective stamp tool 13 and the stamp clamping device 30. A rotary drive 21, which is indicated only schematically in FIG. 4 and which is also centrally controlled, can rotate all stamping tools 13 until the sleeve parts 36, 37 can be pulled apart. When the bayonet connections 17 are pulled apart in this way, the stamping tools 13 are moved to the left in accordance with FIG. 4 until their rear ends have emerged from the region of the hollow piston 16 and the stamping tool block 14 is guided over the T-grooves 26a in a vertical direction out of the tool space can be. This displacement of the stamping tool block 14 can be carried out by hand or by means of a suitable lifting and transport device (not shown), optionally also remotely controlled.

In addition to the advantages of the die block and die-side die block design already described, the basic redesign and automation of the die space of metal forming machines according to the invention creates a tool block quick-change system that significantly expands the production possibilities of such metal forming machines. Due to the rapid changeover, small series can now also be produced cheaply, since the tool life is greater than the number of series due to the new structure of the tool blocks and the low-wear clamping method, which is why a replacement of worn tools, which would necessarily result in machine downtime, has become unnecessary . The relatively long changeover times that are customary in conventional forming machines have the production of small series designed to be costly. In addition to these production-related advantages, the working conditions in connection with the tool room are also improved, since a tool block change can be carried out without great effort. Due to the small amount of time required for a tool block change, there is also enough space, for example, to be able to check and, if necessary, replace other units of the forming machine.

Claims (9)

1.Tool changing device of a multi-stage forming machine used for non-cutting forming of metal parts with a reciprocatingly driven press slide (22) and a stationary machine body (25) opposite this in the stroke direction, each with tool change holders (27, 28) provided on the press slide and the machine body front ), which on the press slide side carry an exchangeable set of stamping tools (13) and on the machine body side a correspondingly matching exchangeable set of die tools (1), characterized in that
the stamping tools (13) are mounted ready for use assembled in a stamping tool cassette block (14) designed in the manner of an interchangeable magazine, which has a clamping surface (29) lying transversely to the central longitudinal axes of the stamp on the counter surface of a stamp clamping device attached to the press slide (22) (30) and at the same time on the press slide front by coupling to the respective punch longitudinal axes coupling clamping elements (35) free of play and non-positively clamped in the stroke direction and that
the die tools (1) in a die tool cassette block (5) also designed in the manner of an interchangeable magazine, on the back of the die on an adapter plate (4) supported by clamping elements (9) acting in the lifting direction are firmly clamped ready for use, and this adapter plate via a clamping surface (31) transverse to the longitudinal center axes of the dies on a clamping plate (7) attached to the machine body (25), in this clamping plate provided clamping elements (6b), can be tightened. 2. Tool changing device according to claim 1, characterized in that the coupling clamping elements (35) on the clamping surface (29) facing side of a clamping plate (24) of the stamp clamping device (30) each have a connecting sleeve (36) with corresponding , at the rear end sections of the stamping tools (13) provided sleeve counterparts (37) can be connected to form a bayonet connection (17) such that each connecting sleeve (36) is connected to a hollow piston (16) which is relatively displaceably guided in the clamping plate (24) and which is a in the distance between each rear stamp end and a support surface (39) of an adjusting wedge (18) vertically displaceably guided in the pressing slide (22) of the pressure piece (19) encloses relatively movable and with appropriate pressure medium application the stamping tool (13) via the associated pressure piece (19 ) and the simultaneously braced bayonet connection (17) against the A supporting surface (39) of the adjusting wedge (18) presses. 3. Tool changing device according to claim 2, characterized in that on the clamping plate (24) a rotary drive (21) for joint rotation of all stamping tools (13) for opening or closing the bayonet connection (17) forming sleeve parts (36, 37) is provided is. 4. Tool changing device according to claim 2 or 3, characterized in that a remotely operable drive (23) is provided for the vertical displacement of each adjusting wedge (18). 5. Tool changing device according to one of claims 2 to 4, characterized in that at least in the displacement of the hollow piston (16) controlling pressure medium circuit (38) a pressure switch is installed, which is connected to an alarm signaling device which triggers too little tension pressure exerted via the hollow piston . 6. Tool changing device according to one of claims 1 to 5, characterized in that in the stamping tool cassette block (14) on the clamping surface side several perpendicular to the row of stamping tools (13) T-grooves (26a) are recessed, in which correspondingly shaped piston head sections ( 32a) of clamping elements (6a) arranged in a clamping plate (24) of the punch clamping device (30) opposite the T-slots (26a) and each consisting of pressure-medium-actuatable piston-cylinder units, that in the clamping surface (29) further At least two centering recesses (12a) are provided, into which correspondingly suitable piston sections (34a) of centering elements (11a), which can also be actuated by pressure medium, are arranged in the clamping plate (24). 7. Tool changing device according to claim 1, characterized in that in the die tool cassette block (5) on the side of the clamping Surface of the adapter plate (4), a plurality of T-grooves (26b) running perpendicular to the row of die tools (1) are recessed, into which correspondingly shaped piston head sections (32b), which are arranged opposite the T-grooves in the clamping plate (7), each of which can be actuated by pressure medium Piston-cylinder units existing clamping elements (6b) can be used, that at least two centering recesses (12b) are also provided in the clamping surface (31), into which correspondingly suitable piston sections (34b) of centering elements (also actuatable by pressure medium) arranged in said clamping plate (7) 11b) can be introduced. 8. Tool changing device according to claim 7, characterized in that the die tool cassette block (5), consisting of the adapter plate (4), which transmits the pressing forces to the body and has only small holes for the ejector, a one-piece, the individual die tools ( 1) and, if necessary, other auxiliary tools, such as bar knives (8), centering plate (2) leading circumferentially in receiving bores (33) as well as clamping glasses (3) individually placed on the end face and the respective die tools (1), starting from the adapter plate (4) Four screws per clamping glasses (3) forming the clamping elements (9) are clamped to the ready-to-install tool unit. 9. Tool changing device according to one of claims 1 to 8, characterized in that for inserting and removing the tool cassette blocks (5, 14) into or out of the tool space of the forming machine formed between the press slide (22) and the machine body (25) a transport device is provided.

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