CLAMPING SYSTEM WITH A LIFT-MOUNTED CLAMPING DEVICE

Description

[0001] The invention relates to a clamping system with a stroke-monitored clamping device, wherein the clamping system comprises a clamping device and a combination bolt. The clamping device houses at least one piston acting on at least three clamping elements and also has a receiving recess for temporarily receiving the combination bolt. The combination bolt is fixably arranged in the receiving recess by means of the clamping elements.

[0002] To clamp a workpiece, for example, on the machine table of a machining center with repeatable accuracy and efficiency, at least one zero-point clamping system can usually be used. Instead of the workpiece, vises, pallets, or similar devices can also be fixed using this system.

[0003] A clamping system called "vb Dock Lock AirLine," published in September 2018 by Vischer & Bolli AG, a tool and clamping technology company from Dübendorf, Switzerland, is described in a brochure. The clamping device features a complexly shaped ring piston with a conical inner wall that acts on clamping segments mounted in a support ring. During the clamping process, these segments clamp onto a combination bolt that can be inserted into a receiving bore. When the clamping system is not in use, the receiving bore is sealed with a cap.

[0004] DE 10 2015 206 590 B3 describes a clamping module and a clamping system, in particular a zero-point clamping system, in which a clamping bolt can be clamped in a receiving bore. For this purpose, three slides arranged radially movable around the centerline of the clamping system are positioned in the clamping module, which support the clamping bolt so as to be laterally displaceable via flat wedge surfaces.

[0005] From JP 2010 076061 A, a machine tool table with a pallet-changing function for clamping pallets is known. The machine table has a device with which the clamping state of the pallet clamping device can be checked. For this purpose, the pallet has four clamping devices arranged in a circle, the pistons of which act on a pivotable index disc. The index disc has four radially arranged grooves into which the conical tips of the pistons protrude to varying depths, depending on the clamping state of the device. The index disc, held against a stop by a spring-like elasticity, makes point contact with the cylindrical surface of the piston cone tip in each groove. As the penetration depth increases, the clamping bolts pivot the index disc. To check the pivot angle, the index disc has two notches on its circumference, the positions of which are scanned by two proximity sensors.The swivel angle is therefore a function of the stroke of the pistons, of which only three angular positions can be detected approximately.

[0006] DE 100 36 885 A1 discloses a quick-release clamping unit, on which the preamble of claim 1 is based, for securing a quick-release clamping pin by means of a piston and deformable clamping elements. When the piston is fully retracted, the base of the housing actuates a switch that signals the completion of the clamping process. Furthermore, compressed air or airflow sensors are provided that measure the air pressure or airflow in the gap between the base and the piston.

[0007] According to DE 10 2012 001 721 A1, a displacement sensor located outside the operating media and a control device are to be used for position monitoring of an actuator. This control device has a high-voltage source for controlling an electrorheological cylinder-piston unit.

[0008] The present invention addresses the problem of developing a clamping system consisting of a clamping device and a combination bolt, the components of which, despite their compact design, ensure high wear resistance, excellent operational reliability with easy adaptability, and a high clamping force. Simultaneously, the clamping process of the combination bolt is to be monitored.

[0009] This problem is solved by the features of claim 1. An adaptable sensor housing is arranged on the housing, in which an absolute displacement measuring system is housed. The displacement measuring system comprises a sensor IC fixed in position within the sensor housing and a magnetic plate mechanically coupled to the piston.

[0010] The invention provides a clamping system in which the clamping elements arranged in the clamping device make full contact with the combination bolt with their clamping surfaces. This results in relatively low surface pressures even under high tensile forces. The large contact areas guarantee high rigidity of the overall system, enabling the clamping device to easily support even large load moments via the combination bolt.

[0011] The clamping elements, which are components of a clamping ring assembled via elastomer bodies, together with an annular piston, form a wedge mechanism in which the axial stroke of the annular piston generates radial clamping forces acting on the clamping ring. The segment-like clamping elements are elastically coupled circumferentially via the elastomer bodies of the clamping ring. In the exemplary embodiment, the annular piston is moved into the clamping position of the clamping device by spring force and held there. If necessary, the clamping process is assisted by compressed air. Compressed air is used to release the tension on the clamping ring and to retract the annular piston—thus releasing the combination bolt. Additionally, the interior of the clamping device is pressurized with compressed air to prevent the ingress of chips, coolant, or lubricant during workpiece machining. Optionally, hydraulic oil can also be used to move the annular piston.

[0012] According to the exemplary embodiment, a sensor housing containing at least one absolute displacement measuring system is arranged as a separate module on the underside of the clamping device. The latter monitors the position or stroke of the piston that adjusts the clamping ring. The sensor housing, which can be adapted to the underside of the clamping device, has, for example, two bolts protruding from its housing cover. These bolts extend into bores in the underside of the clamping device, where they are guided into guide bores and simultaneously attached to the piston. In addition to the sensor(s), the displacement measuring system also includes evaluation electronics.

[0013] The evaluation electronics distinguish at least three stroke positions of the sensor system's magnetic plate. The first position is reached when the piston, due to the action of its return springs, has assumed its upper position. The magnetic plate is in the second position when the piston, against the action of its return springs, has been moved to its other extreme position. The third stroke position does not describe a single point, but rather a specific stroke range. The piston is within this stroke range when it has firmly fixed the combination pin in the zero-point clamping system via the clamping elements. This stroke range is necessary to accommodate the wear on the wedge-drive surfaces of the piston and the clamping elements that occurs during countless load cycles. As wear increases, the clamping stroke of the piston becomes larger. Furthermore, the clamping device allows for the pairing of many different combination pins.Depending on the manufacturing tolerances of the combination bolts, they penetrate the receiving recess to varying depths for secure clamping, theoretically resulting in a separate clamping stroke for each combination bolt. An increase in the clamping stroke, detected by the evaluation electronics, can be displayed as an indicator of impending wear on a device-side display or on the monitor of the PLC connected to the clamping device, e.g., via an IO-Link bus.

[0014] Further details of the invention will become apparent from the dependent claims and the following description of at least one schematically illustrated embodiment. Figure 1: Perspective view of a clamping system with a clamping device with piston position sensing; Figure 2: Section through the unpressurized closed clamping system; Figure 3: Section through the closed clamping system with a pressurized annular piston base; Figure 4: as Figure 3, however with the cleaning piston extended; Figure 5: Section through the clamping system with pressure-loaded ring piston front and with the combination bolt partially immersed; Figure 6: as Figure 5 , however with the combination bolt fully immersed but unlocked; Figure 7: how Figure 6 , however, with the combination bolt locked by means of the spring tension of the ring piston; Figure 8: Tension ring from an oblique top view; Figure 9: Tension ring from an oblique bottom view; Figure 10: Top view of the tension ring; Figure 11: Perspective view of a closure cap from an oblique bottom view with the cleaning piston extended; Figure 12: as Figure 11 , but obliquely from the side; Figure 13: Section through the sensor housing in the plane in which the magnetic disk carrier is mounted; Figure 14: Perspective view into the sensor housing; Figure 15: Perspective view of the clamping device from below; Figure 16: Perspective view of the sensor housing from above.

[0015] The Figure 1Figure 1 shows a clamping system (1) consisting of a clamping device (10) and a combination bolt (130). The clamping device (10) is integrated into a machine table, for example, to hold a workpiece. The workpiece to be clamped typically has at least one combination bolt (130) attached to it, which allows the workpiece to be adapted to the machine table. The housing (11) of the clamping device (10), to the underside of which a sensor housing (150) is attached, contains a mechanism that positions the combination bolt (130) in the clamping device (10) with repeatable accuracy. This mechanism includes a wedge drive (63, 111) whose drive element is an annular piston (40). A dimensioning element (223) is attached to the annular piston (40), which guides the annular piston (40) along a sensor (222) for precise position determination within the sensor housing (150).

[0016] The in Figure 2The illustrated housing (11) essentially consists of a flange-like housing base (12) and a housing cover (31) located in the underside of the housing base (12). Both parts are made, for example, of the rust-, acid- and heat-resistant steel X90CrMoV18.

[0017] The one-piece housing body (12), e.g., 44 mm high, consists of a flange plate (13) and a cylinder (27) integrally formed thereon. The flange plate (13) has a diameter of 112 mm and a wall thickness of 10 mm. The cylinder (27) has an outer diameter of 86 mm and a maximum wall thickness of 6 mm. The flange plate (13) and the cylinder (27) share a common centerline (9). In the transition area between the cylinder (27) and the bottom of the flange plate (13), a chamfer (42), e.g., 5.5 mm wide and with a cone angle of 120 degrees, is provided to increase the rigidity of the housing body (12).

[0018] The flange plate (13) has, in its outer area that projects beyond the cylinder (27), for example eight countersunk holes distributed equidistantly around its circumference for receiving fastening screws (15), by means of which the clamping device (10) can be rigidly attached to the machine table. The countersunk holes are sealed dust-tight with plastic caps. Between each pair of countersunk holes, two precision-machined positioning slots (14), for example 17 mm long and 5.8 mm deep, are machined into the flange plate (13) from the outside. The single positioning slot (14) serves to lock the degree of rotational freedom about the center line (9) when using only one combination bolt (130).

[0019] After Figure 2The flange plate (13) has a channel system (24) on its left side, through which any back pressure present between the flange plate (13) and the workpiece can be fed to a measuring device via a contact port (25) to check that the workpiece is correctly supported. For this purpose, the flange plate (13) has an axial ring groove (29) on its upper surface, which, in the exemplary embodiment, has a depth of, for example, 0.3 mm with an inner diameter of, for example, 48 mm and an outer diameter of, for example, 74 mm. Provided that the workpiece resting on the flange plate (13) completely covers the axial ring groove (29), the back pressure present in the latter can be used for verification. The area of ​​the axial ring groove (29) is at least 25% of the workpiece-bearing upper surface of the flange plate (13).

[0020] The flange plate (13), on whose upper surface the respective workpiece rests, has a central receiving recess (20) which is enclosed by a support tube (16) integrally formed on the flange plate (13). The inwardly projecting support tube (16) has a finely machined end face and a length of 9.5 mm. The wall of the support tube (16) facing away from the receiving recess (20) is a finely machined cylindrical surface for the internal guidance of the annular piston (40).

[0021] The receiving recess (20) has a truncated cone-shaped centering clamping surface (21) in its upper region, the cone angle of which is, for example, 30 degrees. The height of the centering clamping surface (21) measures, for example, 5.6 mm. In its lower region, the receiving recess (20) has a rear grip shoulder (23) that is widened in diameter by, for example, 1 mm.

[0022] The finely machined outer inner wall of the cylinder (27) has a circumferential venting groove (28) in the middle area.

[0023] The housing cover (31) is centered and sealed within the housing body (12) over the inner wall of the cylinder (27). It has a stop tube (32) projecting into the housing body (12) at its center, which surrounds a blind-hole-like recess for the closure cap (33). The latter has a diameter of 28 mm and a depth of 19.3 mm. The center lines of the stop tube (32) and the closure cap recess (33) lie on the center line (9). The stop tube (32) has at least one finely machined end face.

[0024] The outer wall of the stop tube (32) has a finely machined cylindrical outer wall, measuring 11.5 mm in height, which also serves to guide the annular piston (40) internally. The cover wall adjoining the stop tube (32) has a wall thickness of, for example, 10.5 mm. In this area, the housing cover (31) has twelve blind holes (34) arranged in a circle around the center line (9) for mounting and guiding helical compression springs (69). The blind holes (34) have a diameter of 10.6 mm and a depth of 7.3 mm.

[0025] With the clamping device (10) mounted, the distance between the end faces of the support tube (16) and the stop tube (32) is, for example, 6 mm. A clamping ring (100) is arranged between these end faces.

[0026] The clamping ring (100), see. Figures 8 and 9The clamping ring (100) is a ring assembled, for example, from three clamping elements (101) and three spring elements (121), whose cross-section is constant over the entire clamping ring (100). The segment-like clamping elements (101) are made of X90CrMoV18 steel. The spring elements are elastomer bodies (121) made of rubber or a rubber substitute material. Each clamping element (101) individually covers an angle of 85 degrees within the clamping ring (100), while the elastomer bodies (121) cover 35 degrees. In its undeformed state, the clamping ring (100) has an inner diameter of 23 mm and an outer diameter of 35 mm. Its axially measurable width is 0.015 mm smaller than the distance measured between the end faces of the support tube (16) and the stop tube (32). The inner diameter of the clamping ring (100) can be elastically expanded to, for example, 27 mm if required, cf. Figure 5 .

[0027] According to Figure 5The clamping ring (100) has a heptagonal cross-section (102). Its width and height are at least nearly identical. The cross-section (102) is bounded at the top by a flat clamping surface (105), at the bottom by a flat bearing surface (106), internally by a cylindrical inner surface (109), and externally by a frustoconical wedge surface (111) of the clamping ring; see also Figures 8 and 9 . The clamping ring wedge surface (111) has a cone angle of 12 degrees.

[0028] Between the inner surface (109) and the bearing surface (106) is a chamfered, frustoconical clamping surface (108) with a cone angle of 120 degrees. Between the upper clamping surface (105) and the inner surface (109) is a chamfered sliding wedge surface (107) with a cone angle of 90 degrees. In the outer region, the bearing surface (106) transitions into the clamping ring wedge surface (111) via the clamping ring return surface (112), which has a wedge angle of 105 degrees.

[0029] Neglecting the edge rounding, the clamping surface (108) has a chamfer length of, for example, 2.2 mm, the sliding wedge surface (107) of, for example, 2.8 mm, and the clamping ring return stroke surface (112) of, for example, 2.5 mm. Taking the edge rounding and chamfers into account, the effective width of the clamping ring wedge surface (111) is 2.9 mm.

[0030] As the Figures 8 and 9As shown, an elastomer body (121) is positively engaged between each pair of clamping elements (101). For this purpose, the individual clamping element (101) has, in the area of ​​its flat end face, cf. Figure 10 , a recess for rear gripping (115) into which a front-side clamping pin (122) of the adjacent elastomer body (121) engages.

[0031] The rear grip recess (115) is partially a bore (116). It has a diameter of 3 mm and is located, for example, 2.3 mm from the nearest end face of the clamping element (101). Its centerline is parallel to the centerline (9). The centerlines of the bores (116) are located 3 mm from the inner surface (109). An opening, for example, 2 mm wide, is provided between the bore (116) and the end face to form two rear grips (117). The respective clamping pin (122) of the elastomer body (121) has a geometric shape complementary to the rear grip recess (115). The diameter of each clamping pin (122) is slightly larger than that of the bore (116) to securely hold the six parts of the clamping ring (100) together after assembly.

[0032] Inside the clamping device (10) sits the annular piston (40), which can be displaced by, for example, 5.5 mm. The piston has an outer diameter of 70 mm and a piston width of 21.5 mm. The annular piston (40) has a central piston bore (51) with a minimum inner diameter of 33 mm. The front face (41) of the annular piston is chamfered in the outer area to match the base of the flange plate (13). The flat base (45) of the annular piston contains twelve spring guide bores (46), which are arranged opposite the blind bores (34) of the housing cover (31). The outer wall (47) of the annular piston (40) has two sealing ring grooves for receiving sealing rings.

[0033] The piston bore (51) is divided into three areas. The front upper area is the upper sealing zone (52), in which a sealing ring (54) is arranged in a sealing ring groove (53). The sealing ring (54) rests against the outer wall of the support tube (16). The rear lower area is the lower sealing zone (55), in which a sealing ring (57) is also located in a sealing ring groove (56). The lower sealing ring (57) contacts the outer wall of the stop tube (32) of the housing cover (31). All sealing rings are, for example, quad rings.

[0034] In the central area of ​​the piston bore (51), located between the two sealing zones (52, 55), there is an annular groove (61) consisting of a working section (62) and an immersion section (65). The working section (62) has a frustoconical annular groove wedge surface (63) against which the clamping ring (100) is radially supported when the combination bolt (130) is tightened. The annular groove wedge surface (63) has a cone angle of 12 degrees. It extends in the annular groove (61) over a length of, for example, 4 mm.

[0035] After Figure 4The immersion section (65) adjoins the upper end of the immersion section. The latter has a cylindrical groove base with a groove depth of, for example, 3.5 mm. The lower, frustoconical flank of the immersion section forms a return stroke surface (66) with a cone angle of 105 degrees. The immersion section (65) completely accommodates the clamping ring (100) when the end cap (70), moving into the end cap recess (33) of the housing cover (31), passes the clamping ring (100) – beneath its expansion. The transition between the annular groove wedge surface (63) and the return stroke surface (66) is rounded.

[0036] Naturally, the outer wall (47) of the ring piston (40) can have an oval, elliptical, polygonal, or polygonal contour. The same applies to the contour of the inner wall (48).

[0037] The closure cap (70) is an essentially rotationally symmetrical, piston-like component which closes the receiving recess (20) when the clamping device (10) is not in use, cf. Figures 1 to 4 It is also made of X90CrMoV18 stainless steel. Its front face is recessed by 0.3 mm, leaving a 0.9 mm wide rim. The end cap (70) has a cylindrical outer wall with a wave-like collar (71) in its lower section, which, in the closed position, rests against the rear grip shoulder (23) of the receiving recess (20). A stepped bore (72) penetrates the center of the cap, tapering in several stages towards the front face.

[0038] After Figure 4The lower portion of the stepped bore (72) is a cylindrical section (73) with a diameter of 15 mm. The wall of the cylindrical section (73) contains an annular groove for a retaining ring and at least two overflow notches (74). Adjoining the cylindrical section (73) is an air distribution section (75), from which, for example, eight purge bores (76) extend to the radial outer wall of the closure cap (70). The purge bores (76) all lie in the same plane. They terminate tangentially in the air distribution section (75), with their center lines tangent to a circle centered on the center line (9), for example, with a diameter of 10.4 mm. This arrangement of the purge bores (76) creates a helically winding purge flow in the upwardly widening centering gap (22) during purge operation. The air distribution area (75) is followed by a guide bore (77) with a diameter of 6 mm.

[0039] Between the outer wall of the closure cap (70) and the stepped bore (72), a spring guide ring groove (81) is machined into the lower half of the closure cap (70). A closing spring (82), for example a helical compression spring with five coils, sits in this groove and is supported on the bottom of the closure cap recess (33) of the housing cover (31).

[0040] The lower end face of the closure cap (70) has a 1.4 x 45° chamfer according to DIN 406-11 as a spreading chamfer (78). The guide clearance of the closure cap (70) in the receiving recess (20) is less than 0.1 mm.

[0041] The stepped bore (72) is axially secured by a retaining ring, cf. Figure 11, a cleaning piston (85). Its piston, mounted in the cylinder area (73), is guided in the guide bore (77) by its piston rod (86), which is sealed. The piston rod (86) has a through bore (87) which is closed in the piston area, e.g., by means of a threaded pin. An axially discharged nozzle bore (89) is located in the free end face of the piston rod (86). For example, 1 mm below the free end face, there are, for example, eight further radially discharged nozzle bores (89), see also Figure 12 . In the air distribution area (75) the piston rod (86) has at least one radial bore (88) through which the through bores (87) are supplied with compressed air.

[0042] In the Figures 1 to 4The combination bolt (130), not yet inserted into the receiving recess (20), is shown above the clamping device (10). It is also made of the stainless steel X90CrMoV18 and, like the clamping elements (101), hardened to 56 + 3 HRC. The combination bolt (130) serves to clamp the workpiece to the clamping device (10) and simultaneously to precisely center it within the device. It is, for example, a 30 mm long turned part with a central through-hole (139) with an M10 thread. The through-hole (139) has a 3 mm deep countersink with a diameter of, for example, 10.5 mm on the workpiece side. At its opposite end, it has a 90° countersink.

[0043] At the workpiece-side end, the combination bolt (130) is equipped with a locating cylinder section (131) with a diameter of, for example, 18 mm and a height of, for example, 5 mm. It terminates in a flat axial contact surface (132). The part of the combination bolt (130) that, according to the Figure 6 and7 The clamping section (133), which is fully immersed in the receiving recess (20), essentially consists of three areas. The front area is the clamping area (133), and the rear area is the centering area (137). The waist area (136) lies between these two areas. The clamping area (133), which has a diameter of, for example, 26.8 mm in a cylindrical section 1.5 mm wide, serves, among other things, as a rear grip when clamping the workpiece, bearing against the clamping ring (100). For this purpose, it has a frustoconical inner clamping surface (134) with which, in the clamped state, it bears over a large area against the outer clamping surface (108) of the clamping ring (100). The effective flank length of the inner clamping surface (134), taking into account the rounding and radii, is at least 2.4 mm.

[0044] Between the cylindrical section and the front face of the clamping area (133) is a clamping ring return stroke chamfer (135) with a cone angle of 90 degrees. This facilitates the passage of the expanded clamping ring (100) when the combination bolt (130) is inserted into the receiving recess (20).

[0045] The centering area (137) of the combination bolt (130) has a finely machined outer clamping surface (138) facing the inner clamping surface (134), which is used for centering on the centering clamping surface (21) of the receiving recess (20) - according to the Figure 6 and 7 - has a large contact area. The effective flank length, taking into account the rounding and radii, is at least 5.4 mm. The maximum diameter of the outer clamping surface (138) measures, for example, 29.8 mm.

[0046] The waist area (136) has a diameter of, for example, 22 mm. Within this area are two opposing flattened areas, cf. Figure 1, in order to have two attack surfaces for an open-end wrench with a wrench size of 20.

[0047] A sensor housing (150) is attached to the underside of the housing (11), see figure. Figure 16 The sensor housing (150), whose centerline coincides with the centerline (9), consists of a lower housing part (151) and a sensor housing cover (200). Both parts are made, for example, of the aluminum alloy AlSiMgMn. The outer diameters of their cylindrical walls correspond to the outer diameter of the cylinder (27). The lower housing part (151) has a height of, for example, 20 mm, while the height of the sensor housing cover (200) is, for example, 5.5 mm.

[0048] The connection diagram of the pneumatic connections for the clamping pressure, the unlocking pressure, the blow-out pressure and the sealing air is identical or congruent with the connection diagram of the underside of the housing cover (31).

[0049] The cover (200) of the sensor housing (150) is located on the underside of the housing cover (31), see figure. Figure 16 The sensor housing cover (200) can be mounted using, for example, six cover screws (215). The sensor housing cover (200) is attached to the housing cover (31) in front of the lower housing part. The screw heads of the six cover screws (215) are countersunk in the cylindrical recesses of the bores. The cover screws (215) are equidistantly distributed on a circle with a diameter of, for example, 75 mm. In the area of ​​the cable connection, a cover index pin (214) is located in the top of the sensor housing cover (200) to aid in attaching the sensor housing cover (200) to the housing cover (31).

[0050] The sensor housing cover (200) has two bore-like openings (202, 203), see also Figure 13The openings (202, 203) are oriented parallel to the center line (9) and lie on a circle centered on the center line (9), the diameter of which is 40 mm. The center lines of both cover openings (202, 203) are 9 mm apart. A cylindrical recess is located around the cover opening (202), in which a sealing ring (212) is arranged. The two cover openings (202, 203) serve to insert a retaining bolt (172) and a guide bolt (174) for supporting and guiding a magnetic disk carrier (170), respectively. The diameters of the cover openings (202, 203) are 0.1 mm larger than the guide diameters of the retaining bolt (172) and the guide bolt (174).

[0051] In the area of ​​the lid openings (202, 203) on the lid side facing the lower part of the housing (151) there is a rectangular lifting recess (201) e.g. 3 mm deep.

[0052] On a diameter of, for example, 75 mm, there are four cylindrical bores penetrating the sensor housing cover (200), cf. Figure 16 , a clamping pressure cover bore (206), a release pressure cover bore (207), a blow-out cover bore (208) and a sealing air cover bore (209). They are located congruently in front of the connections (36, 37, 38, 39) of the housing cover (31).

[0053] A ring-shaped foil seal (211) is inserted between the sensor housing cover (200) and the housing cover (31), which gas-tightly surrounds all bores (206-209).

[0054] The lower part of the housing (151), see below. Figure 14The sensor housing, which is mounted from below against the sensor housing cover (200), has a housing interior (152), for example, in a cross shape. This interior is divided into four areas. The first area is a cable duct (153) with a depth of 6.5 mm. The second area, adjoining the first and, for example, 10 mm deep, is the fixing area (154), in which the electronics (221) or the hardware of the sensor system (220) is precisely positioned and mounted. The third and largest area is the hardware area (155). Adjoining this is the fourth area, the dimensioning stroke area (156). The latter two areas have a continuous interior floor (157), cf. Figure 7The housing interior (152) is, for example, 18 mm deep. The outer dimensions of the housing interior (152) lie within a circle with a diameter of, for example, 57 mm. In the solid material areas that remain after milling out the cross-shaped form of the housing interior (152), there are four through-holes spaced at 90-degree intervals on a diameter of, for example, 51 mm. The individual through-holes terminate on the underside of the lower housing part (151) in a clamping pressure housing connection (176), a release pressure housing connection (177), a blow-off housing connection (178), and a purge air housing connection (179). Each connection has a short M4 thread, which can be sealed gas-tight by a sealing threaded pin (187).

[0055] To secure a cable (225) connected to the hardware of the sensor system (220), a cable clamp recess (158) is incorporated into the lower part of the housing (151) for a cable feedthrough block (190), see Figure 1. Figure 7 and 15 .

[0056] The cable entry block (190) is a plastic block with a pentagonal, prismatic cross-section. It has two essentially rectangular, equal-sized side faces (191, 192), cf. Figure 14, which meet at right angles, and a large rear surface (193) which is inclined at an angle of 45 degrees relative to each side face (191, 192). The side face (191) lies in the plane of the underside of the lower housing part (151), cf. Figure 15In the central area of ​​each side surface (191, 192) there is a slot (195, 196) for the cable (225). Between the two slots (195, 196) is a clamping groove (197), the width of which is, for example, 20-30% smaller than the width of the two slots (195, 196). The two slots (195, 196) intersect in the area of ​​the back (193), cf. Figure 7 , so that an opening for the cable (225) is provided there. The elongated holes (195, 196) and the clamping groove (197) form the cable entry recess (194). The latter leads, e.g., to Figure 7 , by means of a 45-degree angle drilling into the cable duct (153).

[0057] Along the edge where the side surfaces (191, 192) meet, there are two countersunk holes (171) for receiving the screws (198), the center lines of which form a 45-degree angle with each side surface (191, 192).

[0058] The cable clamp recess (158) of the lower housing part (151) has a geometric shape suitable for receiving the cable entry block (190). Due to the shape of the cable entry recess (194), after the cable (225) has been installed, it is still possible to route the cable (225) either vertically out of the underside of the lower housing part (151) or – as shown in the Figure 1 , 15 and 16 - to protrude vertically from the cylindrical outer wall of the sensor housing (150).

[0059] On a diameter of, for example, 75 mm, the lower housing part (151) has four countersunk holes penetrating the lower housing part (151) to accommodate the housing screws (183). The lower housing part (151) is fastened to the sensor housing cover (200) via these screws. Two further blind holes accommodate two dowel pins (184). A housing index pin (182) is located in a third blind hole, cf. Figure 14 .

[0060] Between the lower part of the housing (151) and the sensor housing cover (200) a ring-shaped foil seal (181) is also inserted, which gas-tightly surrounds all bores located behind the connections (36-39).

[0061] Inside the housing (152), in the hardware area (155), see Figure 14, a circuit board carrier (160) is arranged, which is essentially U-shaped in plan view. The circuit board (221) is fixed to the free end faces of the legs of the circuit board carrier (160) with two screws (166) each, see Figure 14. Figure 7 The circuit board carrier (160) has a carrier flange (161) which is positioned on the base of the fixing area (154) by two dowel pins (162) and fastened with two screws (165). The combination of the two dowel pins (162) and the two screws (165) can be replaced by two dowel screws.

[0062] After Figure 14The magnetic disk carrier (170) projects into the scale-measuring stroke area (156). The magnetic disk carrier (170) is essentially a cuboid body, on the side of which facing the circuit board (221) the magnetic disk (223) is arranged. It has according to Figure 13Two adjacent, identical bores (171) each have a cylindrical countersink. The retaining bolt (172), which penetrates the opening (203) and the guide through-bore (7), is inserted into the bore (171). The retaining bolt has a head with an internal hexagon socket. The free end of the retaining bolt (172) is screwed into a stepped threaded bore (49) of the annular piston (40) via the internal hexagon socket. The cylindrical countersink of the bore (171) has an internal thread in its front region, into which a threaded pin (173) is screwed to fix the retaining bolt (172) in the magnetic disk carrier. Thus, the magnetic disk carrier (170) is rigidly connected to the annular piston (40). The guide bolt (174), which engages in the guide blind hole (8) through the opening (203), is attached to the magnetic disk carrier (170) in the same way as the retaining bolt (172).The guide pin (174) prevents the magnetic disk carrier (170) from pivoting around the center line of the retaining pin (172).

[0063] The sensor system (220) that monitors the stroke of the ring piston (40) consists of a sensor IC (222) and a magnetic scale. The sensor IC (222) is soldered onto the circuit board (221). The component has, for example, dimensions of 5 mm x 5 mm x 1 mm. Two Hall sensors are arranged offset from each other within the sensor IC (222). Opposite the sensor IC (222), at a distance of 0.2 to 1 mm, a magnetic plate (223) with dimensions of 10 mm x 10 mm x 1 mm is positioned as a scale and is glued to the magnetic plate carrier (170). The magnetic plate (223) has a master track and a vernier track adjacent to each other. Both tracks consist of pairs of poles, each consisting of north and south poles, arranged one behind the other. The dimensions of the pole pairs of the vernier track are, viewed in the direction of the relative movement between sensor IC (222) and magnetic plate (223), e.g. 1.5 to 6.3% larger than the dimensions of the pole pairs of the master track.The measuring system is an absolute encoder whose interpolating evaluation - without a reference run - enables position information with a measurement resolution of 3 µm.

[0064] After Figure 2The clamping device (10) is in its unpressurized, unactuated initial state. The end cap (70) is in its closed position. Simultaneously, the annular piston (40) rests against the bottom of the cylinder (27) or against the flange plate (13) due to the action of the helical compression springs (69). The clamping ring (100) contacts the annular groove wedge surface (63) of the annular piston (40). The clamping ring (100) projects approximately halfway into the receiving recess (20). The end cap (70) rests with its expanding chamfer (78) at a distance of approximately 0.1 mm in front of the sliding wedge surface (107), thus preventing the end cap (70) from being opened by a positive locking mechanism. The cleaning piston (85) is located in the end cap (70) in its retracted position. The magnetic disk carrier (170) is in its upper position, partially immersed in the lifting recess (201) of the sensor housing cover (200).

[0065] According to Figure 3The target pneumatic pressure is present at the rear piston base (45) of the annular piston (40). Simultaneously, compressed air enters the receiving recess (20) via the transverse bore (35). There, it acts on the cleaning piston (85) in the end cap (70), forcing it upwards in the stepped bore (72). The compressed air then flows through the overflow notches (74), across the air distribution area (75), into the purge bores (76), and through the through-bore (87) of the piston rod (86) into the extended nozzle bores (89) to purge the face of the end cap (70). The clamping ring (100) and the annular piston (40) seal the gap between the support tube (16) and the stop tube (32).

[0066] After Figure 4Compressed air is applied to the front face (41) of the annular piston, causing the annular piston (40) to rest on the housing cover (31) by compressing the helical compression springs (69). This brings the immersion section (65) to the level of the clamping ring (100). The magnetic plate carrier (170) is moved to its lowest position via the retaining bolt (172) attached to the annular piston (40), so that its underside almost rests on the inner floor (175). Furthermore, the compressed air supply to the receiving recess (20) is interrupted. The cleaning piston (85), assisted by its closing spring (91), retracts into the sealing cap (70). The receiving recess (20) is now prepared for the insertion of the combination bolt (130).

[0067] According to Figure 5The combination bolt (130) is already largely immersed in the receiving recess (20) as the locking cap (70) is pushed forward against the force of the closing spring (82). The clamping area (133) of the combination bolt (130) thereby presses the locking ring (100) into the immersion section (65) of the ring piston (40), stretching the elastomer bodies (121) of the clamping ring (100). The clamping cap (70) was also stretched by the stretching of the elastomer bodies (121) shortly beforehand.

[0068] After Figure 6The combination bolt (130) has come into full contact with the centering clamping surface (21) of the flange plate (13) with its outer clamping surface (138). The axial contact surface (132) of the combination bolt (130) now lies in the plane in which the contact points of the upper surface of the flange plate (13) facing the workpiece are located. The clamping ring (100) has contracted to its initial position, whereby it has largely left the immersion section (65) of the ring piston (40) and its outer clamping surface (108) rests against the inner clamping surface (134) of the piston bolt (130). The end cap (70) is positioned a short distance, e.g. 0.1 mm, from the bottom of the end cap recess (33) of the housing cover (31).

[0069] According to Figure 7After the cylinder chamber located in front of the annular piston face (41) is vented, the annular piston (40) is pushed upwards by the action of the helical compression springs (69) – possibly with compressed air assistance – thereby moving the annular groove wedge surface (63) behind the clamping ring (100) to finally fix the combination bolt (130) in the clamping device (10) and press its clamping elements (101) against the inner clamping surface (134) of the clamping area (133) of the combination bolt (130). A tensile force acting on the combination bolt (130) is introduced into the clamping ring (100) via the clamping area (133) and from there transmitted via the flat clamping surface (105) into the end face of the stop tube (32) and thus into the housing (11).

[0070] If the clamping ring (100) has not yet fully engaged with the inner clamping surface (134) of the clamping area (133) of the combination bolt (130), see below. Figure 6The parts (101, 121) still protruding into the immersion section (65) are pushed against the combination bolt (130) by means of the frustoconical return stroke surface (66) by contact with the clamping ring return stroke surface (112) of the clamping ring (100). The magnetic plate carrier (170) is located in the upper quarter of its travel range. Its exact position varies from combination bolt (130) to combination bolt (130), depending on their machining accuracy. This position is also a function of the wear of all components involved in the clamping process, insofar as they concern the wear-prone clamping surfaces and wedge gear surfaces.

[0071] The measurement deviation from clamping operation to clamping operation is less than 5 µm. The clamping force is in the range of 18 kN.

[0072] Releasing the combination bolt (130) is essentially the reverse of the process. The annular piston (40) is pressed against the housing cover (31) with compressed air, causing the clamping ring (100) to be displaced into the immersion section (65) of the annular piston (40) when the piston bolt (130) is withdrawn. The frustoconical clamping surface (108) of the combination bolt (130) facilitates this process.

[0073] The Figure 13Figure 1 shows the rear of the clamping device (10). Compressed air can be introduced into the clamping device (10) in two different housing areas of this clamping system (1). The usual housing area is the underside of the housing cover (31), where, for example, four connections for compressed air hoses are provided. On the underside, in the area marked "1", there is a release compressed air connection (177). Through this connection, the compressed air is conveyed within the housing (11) to the front of the annular piston (41). In the area marked "3", there is a sealing air connection (179). Through this connection, the compressed air passes, for example, radially through the annular piston (40) into the immersion section (65), and from there along the clamping ring (100) between the support tube (16) and the stop tube (32) into the receiving recess (20).Next to the number "2" is a compressed air connection (176) through which compressed air can be supplied to the annular piston base (45) to assist the clamping movement of the annular piston (40). The blow-out connection (178) is only used if the clamping device (10) is not equipped with a sealing cap (70). In this case, compressed air is blown from the bottom of the sealing cap recess (33) towards the receiving recess (20) to expel any dirt particles located there.

[0074] For hoseless compressed air connection, five connections (17, 18, 19, 26, 25) are provided on the rear of the flange or flange plate (13). These connections are supplied from bores located in the support of the clamping device (10). The connections are the release compressed air connection (17), the blow-off connection (18), the sealing air connection (19), the clamping compressed air connection (26), and a support control connection (25), see [reference]. Figure 2 . Reference symbol list:

[0075] 1 Clamping system 7 Guide through hole for (172) 8 Guide blind hole for (174) 9 Center line 10 Clamping device, assembly 11 Housing 12 Housing base, housing part 13 Flange plate 14 Positioning slots 15 Fastening screws 16 Support tube 17 Release compressed air connection at (13) 18 Blow-off connection at (13) 19 Sealing air connection at (13) 20 Recess 21 Centering clamping surface, frustoconical 22 Centering gap 23 Rear grip shoulder 24 Channel system 25 Support control connection at (13) 26 Clamping compressed air connection at (13), optional 27 Cylinder 28 Venting groove 29 Axial ring groove 31 Housing cover, housing part 32 Stop tube 33 Recess for end cap 34 Blind holes 35 Transverse hole 40 Ring piston 41 Ring piston front, top 42 Piston chamfer, chamfer 45 Ring piston base, piston base 46 Spring guide bores 47 Outer wall 48 Inner wall 49 Stepped threaded bore 51 Piston bore, central 52 Sealing zone, top, part of the piston seal 53 Sealing ring groove, top, part of the piston seal 54 Sealing ring, top, part of the piston seal 55 Sealing zone, bottom, part of the piston seal 56 Sealing ring groove, bottom, part of the piston seal 57 Sealing ring, bottom, part of the piston seal 61 Ring groove, working ring groove 62 Working section 63 Ring groove wedge surface, frustoconical, wedge gear part 65 Immersion section 66 Return stroke surface, frustoconical 69 Helical compression springs, return springs, spring elements 70 Closure cap 71 Wave collar 72 Stepped bore 73 Cylinder area 74 Overflow notches 75 Air distribution area 76 Blow-out holes 77 Guide bore 78 Expanding chamfer 81 Spring guide ring groove 82 Closing spring, helical compression spring 85 Cleaning piston 86 Piston rod 87 Through bore 88 Radial bore 89 Nozzle bore 91 Closing spring, helical compression spring 100 Clamping ring 101 Segmented clamping elements 102 Single cross-section 105 Top clamping surface, flat 106 Bottom bearing surface, flat 107 Top sliding wedge surface, inside 108 Bottom enveloping clamping surface, inside 109 Cylindrical inner surface 111 Clamping ring wedge surface, wedge gear part 112 Clamping ring return stroke surface 115 Rear grip recess 116 Bore 117 Rear grips 121 Spring elements, elastomer body, segmented 122 Clamping pin 130 Combination bolt, assembly 131 Fitting cylinder section 132 Axial contact surface, contact surface 133 Clamping area 134 Inner clamping surface, clamping surface 135 Clamping ring return stroke chamfer 136 Waist area 137 Centering area 138 Outer clamping surface, clamping surface 139 Through hole 150 Sensor housing 151 Housing base 152 Housing interior 153 Cable duct 154 Fixing area 155 Hardware area 156 Scale stroke area 157 Interior floor 158 Cable clamp recess 160 Circuit board support 161 Support flange 162 Dowel pins 165 Screws for (161) 166 Screws for (221) 170 Magnetic plate carrier 171 Bores with cylindrical countersinks 172 Retaining bolt 173 Threaded pin 174 Guide bolt 175 Threaded pin 176 Clamping pressure housing connection 177 Release pressure housing connection 178 Blow-out housing connection 179 Sealing air housing connection 181 Foil seal, ring-shaped for (151) 182 Housing index pin 183 Housing screws 184 Dowel pins 187 Sealing threaded pin 190 Cable entry block 191, 192 Side surfaces 193 Back 194 Cable entry recess 195, 196 Slotted holes 197 Re-clamping groove 198 Screws 200 Sensor housing cover, cover 201 Stroke recess 202 Opening with cylinder countersink 203 Opening 206 Tension pressure cover bore 207 Release pressure cover bore 208 Blow-out cover bore 209 Sealing air cover bore 211 Foil gasket for (200) 212 Sealing ring 214 Cover index pin 215 Cover screws 220 Sensor system 221 Circuit board, populated; electronics 222 Sensor IC, sensor 223 Magnetic plate, scale 225 Cable, five-core 226 Connector

Claims

1. A clamping system with a stroke-monitored clamping device, - wherein the clamping system comprises a clamping device (10) and a combination bolt (130), - wherein the clamping device (10) supports at least one piston (40), which acts on at least three clamping elements (101), in the housing (11) and additionally has a receiving recess (20) for temporarily receiving the combination bolt (130), - wherein the combination bolt (130) can be fixed in the receiving recess (20) with the aid of the clamping elements (101), characterised in that - an adaptable sensor housing (150) is arranged on the housing (11), in which sensor housing an absolute distance measurement system (220) is accommodated, and - the distance measurement system comprises a sensor IC (222), which is arranged in a stationary manner in the sensor housing (150), and a magnetic plate (223), which is mechanically coupled to the piston (40).

2. The clamping system according to Claim 1, characterised in that the magnetic plate (223) has a master track and a vernier track, wherein both tracks are scanned during the measurement process by Hall sensors accommodated in the sensor IC (222).

3. The clamping system according to Claim 1 or 2, characterised in that the positional accuracy of the distance measurement system (220) is 3 µm.

4. The clamping system according to Claim 1, characterised in that the measurement distance of the distance measurement system (220) is at least 5% longer than the stroke of the piston (40).

5. The clamping system according to Claim 1, characterised in that the receiving recess (20) is automatically closable with a closure cap (70).

6. The clamping system according to Claim 1, characterised in that the sensor IC (222) together with the hardware for the evaluation electronics is seated on a printed circuit board (221) arranged in the sensor housing (150).

7. The clamping system according to Claim 1, characterised in that the evaluation electronics differentiate at least three stroke positions of the magnetic plate (223), wherein a first one stands for a receiving recess (20) without combination bolt (130), a second one stands for a receiving recess (20) open for receiving the combination bolt (130), and a third one stands for the clamping of the combination bolt (130) in the receiving recess (20).

8. The clamping system according to Claim 7, characterised in that the stroke positions can be displayed on or in the region of the clamping device (10) by means of LEDs or a display panel.

9. The clamping system according to Claim 1, characterised in that the magnetic plate (223) is fixed to a magnetic plate carrier (170), which is accommodated in the sensor housing (150) and is fastened to the piston (40) so as to be guided linearly in the housing (11).

10. The clamping system according to Claim 1, characterised in that the sensor housing (150) has separate connections (176-179) for all the pneumatic or hydraulic connections of the housing (11), the feed lines of which run through the sensor housing (150).