Forging machine

Abstract

The invention relates to a forging machine having a frame (3) in which rams (2), which can be driven radially with respect to a forging axis (1) and have interchangeably clampable forging tools (4), are mounted, having a gripping device (32) of a manipulator (31) and having a carrier (9) of a tool-changing device, which carrier (9) can be gripped by the gripping device (32) and comprises, on its insertion end opposite the clamping end (10), a carrier arm star (11) with radial carrier arms (13) arranged according to the angular pitch of the rams (2) and comprises a counter-holder (12) opposite the carrier arm star (11) and axially spaced apart therefrom, wherein the counter-holder (12) and the carrier arm star (11), which is axially displaceable relative to the counter-holder (12), have pins (15, 16) which interact with end-face pin receptacles (17) of the forging tools (4) and which form receptacles for the forging tools (4). In order to enable an advantageous tool change, it is proposed that the radial carrier arms (13) each have a pin (15) opposite a pin pair (16) of the counter-holder (12), that the carrier arm star (11) is rotationally adjustable relative to the counter-holder (12) by half the pitch angle of the rams (2), and that the frame (3) forms an axial displacement guide (38) for the counter-holder (12) with an axial stop (41) for the changing position.

Description

[0001] Forging machine

[0002] Technical field

[0003] The invention relates to a forging machine with a frame in which punches with interchangeable clampable forging tools, which can be driven radially to a forging axis, are mounted, with a gripping device of a manipulator that can be displaced coaxially to the forging axis, and with a carrier of a tool changing device that can be grasped by the gripping device at a clamping end in a working position aligned coaxially to the forging axis, the carrier of a tool changing device comprising on its inlet end opposite the clamping end a support arm star with radial support arms arranged according to the angular division of the punches and a counter-holder opposite the support arm star at an axial distance, wherein the counter-holder and the support arm star that can be displaced axially relative to the counter-holder have interoperable pins with end-face plug-in receptacles for the forging tools, which form receptacles for the forging tools.

[0004] State of the art

[0005] For the automation of tool changes in forging machines with punches radially driven with respect to a forging axis and forging tools clamped to these punches, it is known (WO 2016 / 075643 A1) to provide a tool changing device that forms holders for the forging tools at an angular spacing corresponding to the angular spacing of the punches. For this purpose, the tool changing device has a carrier with radially projecting axial webs, between which the holders for the forging tools are formed. The forging tools are axially inserted into guides running along the outer longitudinal edge of the axial webs and locked in the inserted position.The tool changer, loaded with forging tools in this manner, can thus be inserted coaxially to the forging axis between the retracted punches into the forging machine using a manipulator whose gripping device grasps the carrier at an angle relative to the punches. This angled position ensures that the forging tools are held aligned with the punches, so that after the punches are set, the forging tools can be connected to the adjacent punches by clamping devices. After unlocking the insertion position, the carrier can then be pulled out of the forging machine, removing the axial webs from the forging tools clamped to the punches.

[0006] To unload the forging tools, the carrier must first be inserted in reverse order in the aligned angular position between the punches assuming a corresponding stroke position, so that the forging tools can be pushed onto the guides of the axial webs and locked, so that after clamping the forging tools off the punches, the forging tools can be removed from the forging chamber unhindered after retracting the punches.

[0007] To actuate the clamping devices between the punches and the forging tools, pressure plates are provided on opposite sides of the punches. These plates are actuated by means of actuating arms on opposite sides of the tool holders of the carrier. These radial actuating arms are each grouped into a star shape, with the two actuating arm stars on either side of the tool holders being axially displaceable in opposite directions and rotatable on the carrier.While the opposing movement of the two actuating arm stars serves to actuate the pressure plates of the clamping devices, the additional rotation of at least the insertion-side star of the actuating arms is necessary to move these actuating arms axially past the forging tools clamped to the punches in a rotational position aligned with the axial guides, and to rotate them from this insertion position into an actuating position. A disadvantage of such tool-changing devices, however, besides the design complexity, is the fact that the forging tools must be pushed onto and removed from the guides of the axial guides. Given the required tight tolerances, this necessitates precise alignment of the carrier not only axially with respect to the forging axis, but also with respect to its rotational position relative to the punches.The drive for the tool changer carrier provided for this purpose, by a manipulator for the forged workpieces that is usually assigned to the forging machine, is only conditionally suitable for this.

[0008] This also applies to another known tool-changing device for a forging machine (SU 1109234 A), in which a carrier, which can be grasped at a clamping end by a manipulator, has on its insertion end opposite the clamping end a support arm star with radial support arms arranged according to the angular division of the punches and a counter-holder located axially opposite the support arm star. Since the counter-holder and the support arm star, which is axially displaceable relative to the counter-holder, are provided with locking pins that interact with end-face sockets of the forging tools, receptacles for the forging tools are formed between the support arm star and the counter-holder. These tools are grasped by a relative axial displacement of the support arm star and the counter-holder and inserted into the forging machine with the punches open by means of the manipulator grasping the support arm.

[0009] Description of the invention

[0010] The invention is therefore based on the objective of equipping a forging machine with a tool-changing device that, despite being actuated by a manipulator, allows sufficiently precise tool guidance for tool changes, using comparatively simple design features. Starting with a forging machine of the type described above, the invention solves this problem by providing that each radial support arm has a locking pin opposite a pair of locking pins of the counter-holder, that the support arm star is rotatable relative to the counter-holder by half the pitch angle of the punches, and that the frame forms an axial sliding guide for the counter-holder with an axial stop for the tool-changing position.

[0011] The mounting of each individual forging tool by a locking pin on one end and two locking pins on the opposite end allows for simple, precise positioning of the forging tools in the tool changing device by simply shifting the support arm star axially relative to the counter-holder. However, since the forging tools clamped to the punches prevent the support arm star, which rests against the forging tools at their ends, from moving in or out, the support arm star must be rotated by half the pitch angle of the punches relative to the counter-holder when the forging tools are clamped to the punches. This allows the support arms of the support arm star to move through the gap between the forging tools when the carrier is axially shifted.The precise alignment of the tool changing device with respect to the forging axis and the angular division of the punches is ensured by a sliding guide for the counter-holder, which is integrated into the frame of the forging machine. This design precisely defines the spatial position of the tool holders of the tool changing device relative to the frame and thus to the punches. An axial stop for the carrier or counter-holder also allows for precise control over the changing position of the tool changing device relative to the punches.

[0012] To easily rotate the support arm star relative to the counter-holder, the support can be designed as a manipulator-driven support shaft on which the counter-holder is rotatably mounted and supported by a friction clutch. This design allows the counter-holder to rotate relative to the support shaft, which is necessary, for example, to compensate for any deviation of the actual angular position of the support clamped in the manipulator from a target angular position aligned with the frame-side sliding guide for the counter-holder, if this compensation is not achieved by rotating the manipulator's gripping device. With a suitable guide, the counter-holder can thus be automatically aligned with the target rotational position as it is inserted into the set sliding guide by slipping the friction clutch.

[0013] Particularly advantageous design conditions arise when the counter-holder is rotatably mounted on the support shaft with a sleeve and the support arm star are rotatably connected with a sleeve that is rotatably mounted relative to the sleeve and enclosing the sleeve, and when a cam guide for screw adjustment of the support arm star relative to the counter-holder is provided between the sleeve, which is axially adjustable by a spindle drive, and the sleeve.By incorporating a cam track between the sleeve connected to the counterholder and the socket of the support arm star, the axial displacement of the socket relative to the sleeve required for the connection between the pins of the support arm star and the corresponding sockets of the forging tools can be precisely controlled. This axial cam track section allows for precise control of the axial displacement of the socket relative to the sleeve. Simultaneously, the rotation of the support arm star relative to the counterholder can be precisely controlled, as the angle of rotation is determined by the helical cam track extending from the axial section. Therefore, for the coordinated axial and circumferential displacement of the support arm star relative to the counterholder, only the socket of the support arm star needs to be moved along the sleeve of the counterholder by a spindle drive. The spindle drive can be powered by the support shaft.For this purpose, the spindle nut for the spindle drive can be part of the support shaft for axial adjustment of the sleeve. The frictional engagement required for relative rotation of the counter-holder with respect to the support shaft can preferably be ensured by a friction coupling between the sleeve and the support shaft when the counter-holder is arranged on a sleeve rotatable relative to the support shaft.

[0014] To enable the manipulator to grip the beam in a working position coaxial with the forging axis, the clamping end of the beam can have a pivot axis that is horizontal in the beam's working position and perpendicular to the forging axis. This pivot axis engages in a bearing shell of the gripping device. The beam, loaded with forging tools, can thus be inserted into the gripping device in a vertical orientation by inserting the pivot axis of the clamping end into the upwardly open bearing shell of the gripping device. The beam is then pivoted around this axis into a stop-limited working position in which the beam axis aligns with the axis of the gripping device. Actuating the gripping device then clamps the beam in the manipulator in the correct alignment.

[0015] Brief description of the invention

[0016] The invention is illustrated in the drawing as an example. It shows

[0017] Fig. 1 shows a schematic diagram of a tool changing device according to the invention.

[0018] Fig. 2 shows this tool changing device in a section perpendicular to the carrier along line 11-11 of Fig. 1 on a larger scale,

[0019] Fig. 3 shows a section along line III-III of Fig. 2,

[0020] Fig. 4 shows the insertion end of the carrier with the support arm star in an axial section on a larger scale.

[0021] Fig. 5 shows the friction clutch between the sleeve of the counterholder and the support shaft in an axial section on a larger scale; Fig. 6 shows the tool changing device loaded with forging tools in the changing position between the retracted punches of the forging machine in a section according to Fig. 2.

[0022] Fig. 7 shows a section along line VII-VII of Fig. 6,

[0023] Fig. 8 shows a front-side clamping device for the punches for clamping the forging tools in a section on a larger scale.

[0024] Fig. 9 shows the gripping device of a manipulator with a vertically inserted carrier of the tool changing device in a schematic longitudinal section, and Fig. 10 shows a section along line XX of Fig. 6 on a larger scale.

[0025] Ways to implement the invention

[0026] The tool changing device, according to the illustrated embodiment, is designed for a forging machine which, as shown in Figures 6 and 7, has four punches 2 arranged in pairs opposite each other with respect to a forging axis 1. These punches 2, which are radially displaceable in a frame 3 and can be driven in opposite directions in pairs, are equipped with a clamping device for the interchangeable clamping of forging tools 4. Each of these clamping devices comprises two clamping pieces 5, which are pivotably supported on opposite sides of a tool holder 6 of the punches 2 and engage in detent grooves 7 on the end faces of the forging tools 4. As can be seen in Figure 8, the clamping pieces 5 are actuated by springs 8 in the clamping direction, so that when the tool holders 6 are pressed against the forging tools 4, they automatically engage in the detent grooves 7 and hold the forging tools 4 securely.Since the locking grooves 7, for example, form a contact surface for the clamping pieces 5 due to a wedge shape, the forging tools 4 can be released from the tool holder 6 again when a corresponding pulling force is applied.

[0027] The forging tools 4 are moved radially away from the workpiece holders 6 relative to the forging axis 1, with the clamping elements 5 pivoting outwards against the spring force. According to Figures 1 to 3, the tool changing device itself comprises a carrier 9 with a clamping end 10, a support arm star 11 on the insertion end of the carrier 9 opposite the clamping end 10, and a counter-holder 12 arranged at an axial distance from the support arm star 11. The support arm star 11 forms a number of support arms 13 corresponding to the number of punches 2, which are arranged on a sleeve 14 according to the angular division of the punches 2 and each is provided with a locking pin 15. The counter-holder 12 carries two locking pins 16 opposite each locking pin 15, which are preferably arranged symmetrically to the locking pins 15 and together with the locking pins 15 form a three-point mounting for the forging tools 4.For this purpose, the forging tools 4 are provided with sockets 17 for the locking pins 15, 16.

[0028] In order to clamp the forging tools 4 between the support arm star 11 and the counter-holder 12, the support arm star 11 and the counter-holder 12 must be displaced relative to each other in opposite directions so that the locking pins 15, 16 can be inserted into the sockets 17 to lock the forging tools 4 or pulled out of the sockets 17 to release the forging tools 4. According to the illustrated embodiment, the support arm star 11 is axially displaced relative to the counter-holder 12, which is arranged on a sleeve 18 axially fixed relative to the support 9. This sleeve 18 is rotatably mounted on the support 9, which is designed as a support shaft 19, and is connected to the support shaft 19 by a friction clutch 20, as shown in more detail in Fig. 5. The friction clutch 20 comprises, according to Fig.5 a clutch plate 21 between two friction plates 22, one of which is fixed axially to the support shaft 19 and the other is acted upon by clutch springs 23.

[0029] The sleeve 14 of the support arm star 11, which forms the insertion point of the tool changing device, encloses the sleeve 18 and is connected to the sleeve 18 by a cam guide 24 for screw adjustment of the support arm star 11 relative to the counter holder 12. This is shown in particular in the Fig.4 The cam guide 24 has two cam branches offset from each other by 180°, each forming an axial cam section and a subsequent helical cam profile extending over an angle corresponding to half the division angle of the punches 2, so that when axial pressure is applied to the sleeve 14 and thus to the support arm star 11 relative to the counter-holder 12, a travel distance required for withdrawing the pins 15 from the sockets 17 of the forging tools 4 is first traversed before the support arm star 11 is rotated until the radial support arms 13 are aligned relative to the spaces between the forging tools 4 clamped to the punches 2.In the event of opposing forces acting on the sleeve 14, the support arms 13 are first rotated into a position central to the punches 2 before an axial displacement of the sleeve covers the travel required to insert the locking pins 16 into the corresponding sockets 17 and lock the forging tools 4. To secure the forging tools 4 against the counter-holder 12, which determines the aligned position of the forging tools 4, the support arms 13 can additionally be equipped with spring-loaded stop pins 25 that hold the forging tools 4 against the counter-holder 12.

[0030] For axially actuating the sleeve 14, a spindle drive 26 is provided, the spindle nut 27 of which is formed as part of the support shaft 19. The sleeve 14 can thus be repositioned by the spindle 28, for example manually, while the support shaft 19 is held in place. It is also possible to drive the spindle nut 27 via the support shaft 19, but this requires measures to prevent the spindle 28 from rotating. According to the exemplary embodiment, a friction clutch 30 actuated by a spring 29 is provided between the sleeve 14 and the spindle 28 for this purpose.

[0031] The tool changing device is operated by a manipulator 31 associated with the forging machine, which, according to Fig. 9, has a gripping device 32 coaxial with the forging axis 1, for example in the form of a gripping tong with four opposing pairs of jaws 33. To receive the clamping end 10 of the carrier 9, the gripping device 32 is provided with a guide web 34 that is vertical in the receiving position for the carrier 9. At its upper end, the guide web 34 has an upwardly open bearing shell 35 for a pivot axis 36 in one of two diametrically opposed radial retaining legs 37 arranged at the clamping end 10 of the carrier 9. In the working position of the carrier 9, which is clamped in the gripping device 32 and coaxial with the forging axis 1, these retaining legs 37 encompass the guide web 34 on both sides.

[0032] To load the forging machine with a set of forging tools 4, the forging tools 4 are first inserted into the tool changing device, preferably with a vertically oriented support 9, so that the forging tools 4 can be placed onto the locking pins 16 of the locking holder in the open receptacle between the support arm star 11, which is extended into the rotated open position, and the counter holder 12, without obstruction from the support arm star 11. By actuating the spindle drive 26, the support arm star 11 is then rotated into the position for tool locking and axially displaced in order to insert the locking pins 15 into the corresponding sockets 17 of the forging tools 4 and thus lock the forging tools 4 in the tool changing device, in which the forging tools 4 are held in contact with the counter holder 12 by the spring-loaded stop pins 25.The carrier 9, loaded with the forging tools 4, can then be inserted into the upwardly open bearing shell 35 of the gripping device 32 in a vertical orientation with the pivot axis 36, as shown in Fig. 9, and pivoted into a working position coaxial with the forging axis 1, limited by a stop, as indicated by the dashed lines in Fig. 9, in order to be held by the gripper jaws 33. The carrier 9 can thus not only be moved axially relative to the forging machine by the manipulator 31, but also rotated about the forging axis 1, so that no separate drives are required for these adjustments.

[0033] Essential for a proper tool change is the precise alignment of the carrier 9 relative to the punches 2 of the forging machine. While the alignment coaxial with the forging axis 1 can initially be achieved with sufficient accuracy by pivoting the carrier 9, which is suspended in the bearing shell 35 of the gripping device 32, into the stop-limited working position, this is not readily possible for the alignment relative to the angular position of the punches 2. For this reason, the frame 3 of the forging machine has an axial sliding guide 38 for the counter holder 12. According to the exemplary embodiment, two diametrically opposed arms 39 are provided on the sleeve 18, which is rotationally fixed to the counter holder 12. These arms engage with end guide rollers 40 in the sliding guide 38 when the carrier 9 is inserted into the forging chamber of the forging machine using the manipulator 31.If an angular error occurs between the counterholder 12, which determines the rotational position of the loaded forging tools 4, and the sliding guide 38, the friction clutch 20 between the sleeve 18 supporting the counterholder 12 and the support 9 formed by the support shaft 19, which is held non-rotatably in the gripping device 32, allows a relative rotation between the sleeve 18 and the support shaft 19. This makes it possible to easily adjust the rotational position of the counterholder 12 to the predetermined division angles of the punches 2 of the forging machine and thus to precisely align the forging tools 4 with the punches 2. Furthermore, the axial position of the tool changing device is also precisely determined in the axial direction by an axial stop 41 for the arms 39 of the sleeve 18, which is associated with the sliding guide 38 according to Fig. 10.

[0034] In this changeover position, the retracted punches 2 can be positioned against the forging tools 4 held in the tool-changing device in order to clamp the forging tools 4 onto the tool holders 6 of the punches 2. After the forging tools 4 are clamped, the gripping device 32 of the manipulator 31 is driven to actuate the spindle drive 26. The rotation of the support shaft 19, and thus of the spindle nut 27, relative to the counter-holder 12, which is held rotationally fixed by the locking of the forging tools 4, is enabled by the slippage of the friction clutch 20 between the sleeve 18 and the support shaft 19.Due to the cam guide 24, the sleeve 14 is initially displaced axially until the pins 15 of the support arm star 11 are withdrawn from the corresponding sockets 17 of the forging tools 4. With further axial force applied to the sleeve 14, the support arm star 11 is rotated by half the division angle of the punches 2 relative to the counter-holder 12, according to the cam guide 24, and the support arms 13 assume a rotational position between the forging tools 4. In this rotational position, the support arm star 11 can be pulled out of the forging chamber through the spaces between the forging tools 4 by retracting the carrier 9 with the manipulator. This disengages the pins 16 of the counter-holder 12 from the corresponding sockets 17 of the forging tools 4. With the retraction of the carrier 9 and its removal from the gripping device 32, the loading of the forging machine with a set of forging tools 4 is complete.

[0035] To unload the forging tools 4, the carrier 9 is first inserted into the forging chamber using the manipulator 31, in reverse order. The support arms 13 of the support arm star 11, which are in a corresponding rotational position, are moved between the forging tools 4 to the end face of the forging tools 4 opposite the manipulator 31. The locking pins 16 of the counter-holder 12 engage in the corresponding sockets 17 of the forging tools 4. In this changeover position of the counter-holder 12, the support arm star 11 can be rotated into the rotational position of the support arms 13 required for tool locking, in front of the end faces of the forging tools 4. This is achieved by applying corresponding axial pressure to the sleeve via the spindle drive 26 and by rotating the sleeve 14, which depends on the path of the cam guide 24.In the rotational position of the support arm star 11 for locking, the plug pins 15 of the support arms 13 can then engage in the corresponding plug receptacles 17 of the forging tools 4 by a further axial displacement of the sleeve 14, thus locking the forging tools 4 between the support arm star 11 and the counter holder 12. By retracting the punches 2 from the forging tools 4, the tools are released from the clamping devices of the tool receptacles 6 formed by the clamping pieces 5 and can be pulled out of the forging chamber by the manipulator 32.

Claims

Patent claims 1. Forging machine with a frame (3) in which punches (2) with interchangeably clampable forging tools (4) are mounted and which are driven radially to a forging axis (1), with a gripping device (32) of a manipulator (31) which is displaceable coaxially to the forging axis (1), and with a carrier (9) of a tool changing device which can be grasped by the gripping device (32) in a working position coaxially aligned to the forging axis (1) at a clamping end (10), the carrier (9) of a tool changing device which comprises on its inlet end opposite the clamping end (10) a support arm star (11) with radial support arms (13) arranged according to the angular division of the punches (2) and a counter-holder (12) opposite the support arm star (11) at an axial distance, wherein the counter-holder (12) and the support arm star (11) which is displaceable axially relative to the counter-holder (12) are joined by locking pins (15) with end-face plug-in receptacles (17) of the forging tools (4). 16) exhibit,the receptacles for the forging tools (4) are characterized in that the radial support arms (13) each have a pin (15) opposite a pair of pins (16) of the counterholder (12), that the support arm star (11) is rotatable relative to the counterholder (12) by half the division angle of the punches (2), and that the frame (3) forms an axial displacement guide (38) for the counterholder (12) with an axial stop (41) for the changeover position.

2. Forging machine according to claim 1, characterized in that the counterholder (12) is rotatably mounted on the support (9) designed as a support shaft (19) and is connected to the support shaft (19) by a friction coupling (20).

3. Forging machine according to claim 2, characterized in that the counterholder (12) is rotatably mounted on the support shaft (19) with a sleeve (18) rotatably mounted on the support shaft (19) and the support arm star (11) is non-rotatably connected to a sleeve (14) rotatably mounted relative to the sleeve (18) and enclosing the sleeve (18), and that between the sleeve (14) which is axially adjustable by a spindle drive (26) and the Sleeve (18) a cam guide (24) for screw adjustment of the support arm star (11) relative to the counterholder (12) is provided.

4. Forging machine according to claim 3, characterized in that the spindle nut (27) for the spindle drive (26) for axial adjustment of the sleeve (14) is part of the support shaft (19).

5. Forging machine according to claim 3 or 4, characterized in that the friction clutch (20) is provided between the sleeve (18) and the support shaft (19).

6. Forging machine according to one of claims 1 to 5, characterized in that the clamping end (10) of the carrier (9) has a pivot axis (36) which is horizontal in the working position of the carrier (9) and which is perpendicular to the forging axis (1) and the gripping device (32) has a bearing shell (35) which receives the pivot axis (36).

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