Safety device for a clamping station, clamping station and retrofit kit

Abstract

Safety device for a clamping station, clamping station with a safety device and retrofit kit for a safety device.

Description

[0001] The invention relates to a safety device for arrangement on a clamping station for in particular a turning application, a clamping station for in particular a turning application and a retrofit kit for retrofitting a clamping station for in particular a turning application.

[0002] Rotary clamping stations are known from the prior art and are offered and sold by the applicant at the time of application under the name “Turn” clamping stations, such as the NSL3 turn 450-3 clamping station (Ident. No. 1323582). Such clamping stations are used in particular in milling-turning centers as a basis for rapid changeover processes. The clamping stations generally comprise a round base plate, in particular, on which fluidically, i.e. fluidically or hydraulically actuated clamping modules are arranged. The clamping modules have clamping devices for locking components, component carriers or tools to the clamping module, whereby the clamping devices are usually in their closed position and pre-tensioned by means of closing springs. In particular, zero-point clamping modules can be used as clamping modules, as are known, for example, from EP 1 707 307 A1. The clamping stations orTheir base plates include various channels for actuating the clamping modules, in particular opening channels connected to the clamping module-side opening chambers for opening the respective clamping device, and closing channels connected to the clamping module-side closing chambers for closing the respective clamping device. To open the clamping devices, the respective opening chambers are ventilated or pressurized with compressed air to open the clamping devices against the closing springs.

[0003] The known clamping stations feature a turbo function, according to which the spring-operated closing process is actively supported by air pressure; the closing chambers are briefly pressurized with compressed air. This increases the retraction and clamping force of the clamping modules. In the known clamping stations, this is achieved by removing a fluid coupling from an opening connection provided on the clamping station, which is connected to the opening channels, and plugging the fluid coupling into a separate closing connection provided on the clamping station, which is connected to the closing channels. Whether such a connection change has occurred can be read from a visually monitored indicator pin. When the fluid coupling is connected to the closing connection, the indicator pin is extended from its recessed position to a raised position (see, for example, the Assembly and Operating Instructions, NSL3 turn 450-3, 450-3-Z, 570-5, 570-5-Z, p.24 of the applicant).

[0004] DE 1 006 236 B discloses a safe valve actuation for clamping devices, by means of which a clamping piston can be alternately pressurised and the other side can be released.

[0005] DE 26 15 184 A1 discloses a blocking element for a fluid connection with movement coupling of a valve.

[0006] The present invention is based on the object of improving known clamping stations in their application, so that in particular visual monitoring of the turbo indicator pin can be dispensed with.

[0007] This object is achieved with a safety device according to claim 1. Such a safety device can ensure that the fluid coupling at the fluid connection is locked via the locking element as long as the clamping modules are open. Before the fluid coupling at the fluid connection is removed, the movement coupling between the locking element and the valve piston automatically supplies fluid, in particular ventilated or pressurized, to the closing transfer point, and thus to the closing channels and ultimately to the respective module-side closing chamber, thereby forcibly implementing the turbo function described above. Instead of supplying compressed air, it is also conceivable to operate the device hydraulically, so that it is supplied with hydraulic fluid.Overall, the turbo indicator pin known from the prior art can be completely eliminated, as it is always guaranteed that the turbo function is initiated when the locking element is moved from the locking position to the removal position. This improves the handling and functional reliability of the clamping station for a turning application equipped with a safety device according to the invention.

[0008] It is further advantageous if the valve piston is further configured such that, in the basic position, it connects the closing transfer port to a pressure relief line for reducing the pressure in at least one closing channel, and, in the closed position, it connects the opening transfer port to the pressure relief line for reducing the pressure in at least one opening channel. This achieves—in a pneumatic design—automated, alternating venting of the respective non-vented channels or lines.

[0009] Manual venting or other means to enable venting are not required.

[0010] Furthermore, a hand lever pivotable about a pivot axis can be provided for the movement coupling between the blocking element and the valve piston. The hand lever is operated manually, in particular, to be able to remove or attach the fluid coupling, in particular from the fluid connection. The pivot axis is preferably located between the valve piston and the blocking element. Depending on the distance of the pivot axis from the valve piston or the blocking element, suitable transmission ratios for the movement coupling can be achieved.

[0011] It is advantageous if the hand lever is coupled to the locking element via a first ball segment and / or to the valve piston via a second ball segment. Overall, this allows for a reliable and low-friction coupling.

[0012] According to the invention, the locking element or fluid coupling can have a U-, V-, C-, or fork-shaped locking section, wherein the fluid coupling or locking element has a locking recess, in particular in the form of a circumferential groove, which interacts with the locking section in the locking position. For locking, the locking section then engages in the locking recess. The locking recess is preferably located in a plane perpendicular to the withdrawal direction in which the fluid coupling is withdrawn from the fluid connection.

[0013] In order to ensure that the locking element remains in its locking position, it is advantageous if a spring element is provided which urges the locking element and / or the valve piston into the locking position.

[0014] An advantageous and compact movement coupling is obtained in particular when the blocking element is designed as a blocking slide that can be displaced along an axis, when the valve piston can be displaced along a valve piston axis and when the axis runs at least largely parallel to the valve piston axis.

[0015] Advantageously, the safety device comprises a housing in which the blocking element is movably mounted, on which the fluid connection is arranged, in which the pressure line is provided, in which the valve piston is displaceably mounted, in which a closing line opening into the closing transfer is provided, in which an opening line opening into the opening transfer is provided, and / or in which at least one pressure relief line for venting the closing line or the opening line is provided.

[0016] Advantageously, the fluid connection is also arranged on the housing and the housing has a guide for the blocking element.

[0017] It is also advantageous if a valve bore is provided in the housing to accommodate the valve piston, and if sleeve-like spacers and ring-like seals are provided in the valve bore to form valve chambers. The valve bore can be designed, in particular, as a blind bore and can be closed with a cover, which can serve as an end stop for the valve piston. The dual function of the cover allows for component savings and increases the precision of the safety device.

[0018] The opening and closing switches are also located on the housing. Preferably, all functional components of the safety device are located in or on the housing.

[0019] The object mentioned at the outset is also achieved by a clamping station for a turning application having the features of claim 11. Such a clamping station then comprises the safety device according to the invention.

[0020] The object mentioned at the outset is also achieved by a retrofit kit for retrofitting a tensioning station, wherein the retrofit kit has the features of claim 12. By means of such a retrofit kit, in particular a tensioning station described at the outset and known from the prior art can be retrofitted in a simple manner with a safety device according to the invention.

[0021] Further details and advantageous embodiments of the invention can be found in the following description, which describes and explains an embodiment of the invention in more detail. The figures show: Fig. 1: a clamping station for turning applications with a safety device, Fig. 2: the safety device Fig. 1 with locked fluid coupling, Fig. 3: the safety device Fig. 2 without fluid coupling, Fig. 4: the safety device Fig. 2 in front view, Fig. 5: the safety device Fig. 2 in bottom view, Fig. 6: a section through the safety device along line VI in Fig. 4 in peeling position, Fig. 7: a section through the safety device along line VII in Fig. 4, Fig. 8: a circuit diagram of a safety valve of the safety device according to Fig. 2.

[0022] In the Fig. 1 shows a clamping station 10 for turning applications. The clamping station 10 comprises a base plate 12, which is round in plan view, on which clamping modules 14 are arranged. The clamping station 10 can be used, for example, in milling and turning operations, whereby the clamping modules 14 can be used to clamp workpieces to be machined reliably and reproducibly with high precision. Zero-point clamping modules, such as those known, for example, from EP 1 707 307 A1, can be used as the clamping modules 14.

[0023] To secure the tools, the clamping modules 14 have clamping devices 16, in particular clamping slides or clamping balls, which generally interact with a clamping pin provided on the workpieces in such a way that when the clamping devices 16 are moved into a closed position, the clamping pin together with the tool is retracted into the clamping module and secured to the top side 18 of the respective clamping module 14. The clamping modules 14 comprise closing springs that urge the clamping devices 16 into their closed position to prevent unintentional opening of the clamping modules.

[0024] The clamping station 10, or its base plate 12, has Fig. 1 schematically depicts opening channels 18 and closing channels 20. The opening channels 18 connect an opening connection provided in the base plate 12 to the clamping modules 14 arranged on the base plate 12 or to their opening chambers on the clamping module side. Consequently, the opening chambers of the clamping modules 14 can be ventilated or pressurized via the opening channels 18, thereby forcing the clamping devices into their open position against the spring force of the closing springs.

[0025] The closing channels 20 connect a closing connection provided in the base plate 12 on the base plate side with closing chambers on the clamping module side. Although the clamping devices 16 are, as described, generally urged into their closed position by means of closing springs, it is nevertheless desirable to actively support the closing process by supplying the clamping module-side closing chambers with compressed air, in particular, via the closing channels, at least briefly during the closing process. These safety functions were also referred to at the beginning as a turbo function. Even though pneumatic operation of the safety device 30 is described below, it is conceivable to operate the system hydraulically, in particular with hydraulic oil.

[0026] To ensure that when the clamping modules 14 are closed, their pressure chambers are at least briefly pressurised with compressed air, a Fig. 1, a safety device 30 is provided which is arranged on the base plate 12 or can be arranged there.

[0027] As can be seen from the Fig. 2 and Fig. 3, the safety device 30 has a housing 32 on which a fluid connection 34 in the form of a pneumatic nipple is arranged. The fluid connection 34 is particularly Fig. 3 clearly visible. In Fig. 2, a fluid coupling 36 is provided on the fluid connection 34, which forms the free end of a compressed air hose 38. During operation, the compressed air hose 38 is connected to a compressed air source 39.

[0028] Furthermore, in particular from the Fig. 2 and Fig. 3 clearly shows that a clamping element 40 in the form of a locking slide is provided, which has a Fig. 2 shown locking position. In the locking position, the fluid coupling 36 is locked to the fluid connection 34, and thus to the safety device 30. For this purpose, the locking element 40 has a U-shaped or semicircular locking section 42, which engages in a locking recess provided on the fluid coupling 36 in the form of a groove 44. The groove 44 lies in a plane that runs perpendicular to the fluid connection 34, or to its longitudinal axis 46. The locking element 40 can also have a Fig. 3, in which the fluid coupling 36 can be removed from the fluid connection 34 along the longitudinal axis 46.

[0029] The slide-like locking element 40 is arranged on the housing 30 in a guide groove 47 so that it can be moved between the locking position and the removal position by means of a hand lever 48.

[0030] As can be seen from the Fig. 4 and Fig. 5, the safety device 30, or its housing 32, has two connections on the underside facing the base plate 12, namely an opening transfer 50 and a closing transfer 52. In the assembled state, the opening transfer 50 corresponds to the opening connection on the base plate side and the closing transfer 52 corresponds to the closing connection on the base plate side.

[0031] As can be seen from the Fig. 6 and Fig. 7, the hand lever 48 is mounted in the housing 32 so as to be pivotable about a pivot axis 54. The hand lever 48 is motion-coupled to the locking element 40 via a first ball segment 56, wherein the locking element 40 has a particularly circular recess 58 for receiving the ball segment 56. On the side of the ball segment 56 facing away from the pivot axis, a further ball segment 60 is provided, which engages a bore 62 of a valve piston 64. The described arrangement consequently achieves a motion coupling between the locking element 40, the hand lever 48, and the valve piston 64.

[0032] The valve piston 64 is movable between a home position and a closed position and is urged into its home position by a spring element 65. The arrangement is such that the valve piston 64 is in the home position when the locking element 40 is in the locking position and that the valve piston 64 is in the closed position when the locking element 40 is in the removal position.

[0033] The valve piston 64 is located in a valve bore 66 formed in the housing 30, which is designed as a blind hole and closed with a cover 67. The cover 67 can serve, in particular, as an end stop for the valve piston 64.

[0034] Sleeve-like spacers 68 and ring-like seals 70 are provided in the valve bore 66 to form valve chambers 72, which, together with the valve piston 64, form a safety valve 73. The valve piston 64 as such has valve seats 75 with different diameters, which interact with the seals 70 to create valve chambers or connections.

[0035] Out of Fig. 6 it becomes clear that a pressure line 74 is provided between the fluid connection 34 and the valve bore 66 in the housing 32, which opens into the valve bore 66 at a position A.

[0036] Out of Fig. 6 further shows that the closing transfer 52 is connected to the valve bore 66 via a closing line 76, wherein the closing line 76 opens into the valve bore 66 in position B. The design of the valve piston 64 and the spacers 68 as well as the seals 70 are such that in the Fig. 6, the positions A and B are fluidically connected, so that compressed air coming from the hose 38 can flow according to the arrows 78 through the fluid coupling 36, the fluid connection 34, the pressure line 74 via the position A into the position B to the closing line 76 and further to the closing transfer 52.

[0037] Out of Fig. 6 further shows that the opening transfer 50 opens into the valve bore 66 via an opening line 80 at position C. If the locking element 40 is moved into the locking position with the hand lever 48, the valve piston 64 is in the Fig. 6 is moved to the left so that the pressure line 74 or position A, in which the pressure line 74 opens into the valve bore 66, is fluidically connected to position C. At the same time, the connection between positions A and B is interrupted. In the locking position, compressed air flows from the hose 38 via the fluid coupling 36 and the fluid connection 34 into the pressure line 74 and via position A into the valve bore 66. From there, the compressed air flows via position C into the opening line 80 to the opening transfer point 50. As a result, the opening channels 18 on the clamping station side and the opening chambers on the clamping module side are pressurized with compressed air, causing the clamping devices 16 to move into their open position.

[0038] In the Fig. 7, pressure relief lines in the form of vent lines 82 are shown in the housing 32, which open into a vent opening 84. The vent lines 82 connect the vent opening 84 with the positions D and E in the valve bore 66. In the Fig. In the removal position shown in Figure 7, the position of the valve piston 64 is such that positions D and C are fluidly connected to each other. This means that the opening chambers of the clamping modules 14 are then vented via the clamping station-side opening channels 18, the opening transfer 50, and the venting channels 82, so that air can flow out.

[0039] Accordingly, in the locking position of the locking element 40, positions B and E are fluidically connected to one another, so that the closing chambers of the clamping modules 14 are vented.

[0040] When operating the clamping station, a workpiece change can proceed as follows: Initially, workpieces are located in the clamping modules 14. The hand lever 48 is, as Fig. 6, is moved into the removal position so that the fluid coupling 36 can be plugged onto the fluid connection 34. The hand lever 48 is then released, whereby the locking element 40 is moved into its locking position due to the spring force of the spring element 65 and the valve piston 64 is moved into its home position. As a result, the pressure line 74 is connected to the opening transfer point 50. Compressed air therefore flows through the safety device 30 into the clamping station 10 and ventilates the opening channels 18 or the opening chambers of the clamping modules 14. At the same time, the closing channels 20 are vented via the vent lines 82. The clamping modules are opened against the spring force of the closing springs, i.e. the clamping devices 16 are moved into their open positions. Workpieces locked in the clamping modules can then be removed orOther workpieces can be inserted into the clamping modules 14 in an automated manner.

[0041] To lock workpieces in the clamping modules 14, the hand lever 48 is operated, in particular manually, so that the locking element 40 is moved into the removal position and the valve piston 64 is moved into the closed position. This vents the opening chambers of the clamping modules 14 via the vent lines 82, causing the clamping devices 16 to move into their closed position due to the closing springs. Furthermore, in accordance with the desired turbo effect mentioned above, the pressure line 74 is connected to the closing transition 52, so that the closing chambers of the clamping modules 14 are ventilated, i.e., actively pressurized with compressed air, in addition to the force of the closing springs. After the locking element 40 has been moved into the removal position, the fluid coupling 36 can be removed from the fluid connection 34. The workpieces are locked to the clamping modules using the turbo function.The clamping station 10 with the workpieces can be used in particular in a milling-turning application.

[0042] In the Fig. Figure 8 shows a locking mechanism 90 of a clamping module 14 and a circuit diagram of the safety valve 73 used in the safety device 30. The system boundary between the clamping module 14 and the safety device 30 is indicated by the dashed line 81. The locking mechanism 90 comprises a cylinder 92 and a piston 94, which divides the cylinder 92 into a closing chamber 96 and an opening chamber 98. The piston 94 actuates a schematically illustrated clamping means 16 via a piston rod 100 and preferably with the interposition of a gear unit (not shown). Closing springs 97 are provided in the closing chamber 96, which urge the piston 94, and thus the clamping means 16, into the closed position.

[0043] The closing chamber 96 is connected to the closing channel 20, which opens into a clamping station-side closing connection, which is fluidically connected to the closing transfer 52 of the safety device 30. Accordingly, the opening chamber 98 is fluidically connected to the opening transfer 50 of the safety device 30 via the opening channel 18, which opens into a clamping station-side opening connection.

[0044] In the in the Fig. In the first valve position shown in Figure 8, the opening chamber 98 is connected to the compressed air source 39, so that the clamping means 16 are moved into their open position against the force of the closing spring 97. The closing chamber 96 is connected to a vent 84. If the valve 73 is moved to the second (in Fig. 8 left) valve position, the compressed air source 39 is connected to the closing chamber 96 and the opening chamber 98 is vented. This valve position corresponds to the turbo function described above.

[0045] By using the described safety device 30, it is always ensured that the clamping modules 14 or their closing chambers 96 are ventilated according to the turbo function before the fluid coupling 36 or the pressure source 39 is removed.

[0046] The described safety device 30 also has the advantage that it can be used in a simple manner to retrofit existing clamping stations.

Claims

[1] Safety device (30) for arrangement on a clamping station (10) for in particular a turning application, wherein the clamping station (10) has at least one clamping module (14) with at least one clamping means (16), at least one opening channel (18) connected to a clamping module-side opening chamber (96) for opening the clamping means (16), and at least one closing channel (20) connected to a clamping module-side closing chamber (96) for closing the clamping means (16), wherein the safety device (30) comprises - a fluid connection (34) for connecting a fluid coupling (36) which can be connected to a pressure source (39) via a pressure hose (38), - a locking element (40) which is displaceable between a locking position in which the fluid coupling (36) can be locked to the fluid connection (34) and a removal position in which the fluid coupling (36) can be removed from the fluid connection (34), - a safety valve (73) having a valve piston (64) which can be moved between a basic position and a closed position, - a pressure line (74) provided between the fluid connection (34) and the valve piston (64), and - an opening transfer (50) for connection to the opening channel (18) and a closing transfer (52) for connection to the closing channel (20), and wherein the movement coupling between the blocking element (40) and the valve piston (64) is such that when the blocking element (40) is in the locking position, the valve piston (64) is in the basic position and when the blocking element (40) is in the removal position, the valve piston (64) is in the closed position, and wherein the valve piston (64) is designed such that in the basic position it connects the pressure line to the opening transfer (50) and in the closed position it connects the pressure line to the closing transfer (52). [2] Safety device (30) according to claim 1, wherein the valve piston (64) is further designed such that in the basic position it connects the closing transfer (52) to a pressure relief line (82) for reducing the pressure in the at least one closing channel (20) and in the closed position it connects the opening transfer (50) to the pressure relief line (82) for reducing the pressure in the opening channel (18). [3] Safety device (30) according to claim 1 or 2, wherein a hand lever (48) pivotable about a pivot axis (54) is provided for the movement coupling between the blocking element (40) and the valve piston (64). [4] Safety device (30) according to claim 3, wherein the hand lever (48) is coupled in motion to the blocking element (40) via a first ball segment (56) and / or to the valve piston (64) via a second ball segment (60). [5] Safety device (30) according to one of the preceding claims, wherein the locking element (40) or the fluid coupling (36) has a U-, V-, C- or fork-shaped locking section, and wherein the fluid coupling (36) or the locking element (40) has a locking recess (44) cooperating with the locking section in the locking position. [6] Safety device (30) according to one of the preceding claims, wherein a spring element (65) is provided which urges the valve piston (64) and / or the blocking element (40) into the locking position. [7] Safety device (30) according to one of the preceding claims, wherein the blocking element (40) is designed as a blocking slide displaceable along a blocking slide axis, wherein the valve piston (64) is displaceable along a valve piston axis and wherein the blocking slide axis extends at least largely parallel to the valve piston axis. [8] Safety device (30) according to one of the preceding claims, wherein a housing (32) is provided, - in which the locking element (40) is slidably mounted, - on which the fluid connection (34) is arranged, - in which the pressure line (74) is provided, - in which the valve piston (64) is slidably mounted, - in which a closing line (76) is provided which opens into the closing transfer (52), - in which an opening line (80) is provided which opens into the opening transfer (50), and / or - in which a pressure relief line (82) is provided for venting the closing line (76) or the opening line (80). [9] Safety device (30) according to one of the preceding claims, wherein a housing (32) is provided in which a valve bore (66) is provided for receiving the valve piston (64), wherein sleeve-like spacers (68) and ring-like seals (70) are provided in the valve bore (66) for forming valve chambers (72). [10] Safety device (30) according to claim 9, wherein the valve bore (66) is closed with a cover (67), the cover serving as an end stop for the valve piston (64). [11] Clamping station (10) for in particular a turning application, comprising at least one clamping module (14) with at least one clamping means (16), an opening channel (18) which is connected to a clamping module-side opening chamber (98) for opening the clamping means (16), and a closing channel (20) which is connected to a clamping module-side closing chamber (96) for closing the clamping means (16), and comprising a safety device (30) according to one of the preceding claims, wherein the opening channel (18) is connected to the opening transfer (50) and the closing channel (20) is connected to the closing transfer (52). [12] Retrofit kit for retrofitting a clamping station (10) for in particular a turning application comprising a safety device (30) according to at least one of claims 1 to 10 and a fluid coupling (36) for connection to a pressure hose (38), wherein the fluid coupling (36) has a locking recess (44) for cooperation with a locking section (42) on the blocking element side.

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