Hollow piston cylinder

Abstract

The invention relates to a hollow piston cylinder (1) for clamping a component, for example a tool or a workpiece, comprising a clamping cylinder (4), a hollow piston (5) displaceable in the clamping cylinder (4), and a pull rod (2) anchored in an axial bore of the hollow piston (5). When displaced in the axial direction by a pressure medium, the hollow piston (5) moves the pull rod (2) along in the axial direction. The invention provides that the pull rod (2) can be anchored in the axial bore in the hollow piston (5) in a plurality of axial positions.

Description

Technical Field

[0001] This invention relates to a hollow piston cylinder for clamping components, and more particularly, to a hollow piston cylinder for clamping tools or workpieces. Background Technology

[0002] Hollow piston cylinders are known in the prior art and are ideal for clamping workpieces with continuous through holes or openings.

[0003] Figure 1 shows an example of such a conventional hollow piston cylinder 1 known in the prior art. The known hollow piston cylinder 1 firstly has a tie rod 2 that is axially movable in the direction of the double arrow and has a T-slot head 3 located at the free end of the tie rod 2 so as to engage with a T-slot in a component to be clamped.

[0004] In addition, the hollow piston cylinder 1 has a clamping cylinder 4, in which the hollow piston 5 can move in the axial direction.

[0005] Several seals 6, 7, and 8 are provided to seal the hollow piston 5 in the clamping cylinder 4, whereby the seal 6 is arranged on the outer circumferential surface of the hollow piston 5, while the seals 7 and 8 are positioned on the operating surface of the clamping cylinder 4.

[0006] The pull rod 2 is anchored in the hollow piston 5 via a screw connection 9. For this purpose, the pull rod 2 has an external thread, which forms the screw connection 9 with a corresponding internal thread located in the axial opening of the hollow piston 5. When the hollow piston 5 moves axially within the clamping cylinder 4, the hollow piston 5 thus drives the pull rod 2 to move along with it in the axial direction.

[0007] The screw connection 9 between the hollow piston 5 and the pull rod 2 is self-locking, so that the axial tensile load on the pull rod 2 will not cause the screw connection 9 to loosen, thus not changing the axial position of the pull rod 2 in the hollow piston 5.

[0008] Furthermore, the hollow piston cylinder 1 has a spherical disc 10, which has a flat contact surface 11 on the clamping side and a spherical surface 12 on the opposite side. When clamping on uneven clamping edges, the spherical disc 10 allows the clamping cylinder 4, the hollow piston 5, and the pull rod 2 to perform slight rotational movements.

[0009] The hollow piston 5 and the pull rod 2 are hydraulically driven via the hydraulic connector 13, and hydraulic oil can be supplied to the pressure chamber 14 via the hydraulic connector 13. When hydraulic oil is introduced into the pressure chamber 14, the hollow piston 5 moves upward from the released starting position shown in the figure to the clamping position of the hollow piston 5.

[0010] To return the hollow piston 5 from its upper clamping position to the lower released initial position shown, the hollow piston cylinder 1 has a helical spring 15 that pre-tensions the hollow piston 5 downwards to its released initial position. The helical spring 15 is supported on one side by the circumferential collar of the hollow piston 5 and on the other side by a housing canister 16, which is fixed to the top of the clamping cylinder 4 by screws.

[0011] It should also be mentioned that the pull rod 2 has a radially continuous transverse opening 17 at its upper end, which is used to lock and fix the pull rod 2 in the hollow piston cylinder 1. For this purpose, a radially continuous receiving opening 18 is also provided in the hollow piston 5. In order to lock, the pull rod 2 is then screwed into the hollow piston cylinder 1 until the receiving opening 18 in the hollow piston 5 is aligned with the transverse opening 17 in the pull rod 2. Then the locking bolt 19 can be inserted, which passes through the receiving opening 18 and the transverse opening 17, thereby locking the pull rod 2. Since the pull rod 2 cannot be rotated, the screw connection 9 cannot be loosened.

[0012] The known disadvantage of the hollow piston cylinder 1 is that it is inflexible in terms of the size of the part to be clamped, because the functional dimensions are predetermined by the design and cannot be changed. Summary of the Invention

[0013] The objective of this invention is to create a corresponding improved hollow piston cylinder that is flexible in terms of possible functional dimensions.

[0014] This task is solved by the hollow piston cylinder according to the main claim of the invention.

[0015] The hollow piston cylinder according to the present invention is typically used for clamping components, such as tools or workpieces.

[0016] Corresponding to the known hollow piston cylinder described at the beginning, the hollow piston cylinder according to the invention also has a clamping cylinder in which the hollow piston can be driven by a pressure medium (e.g., hydraulic oil) and moves in the axial direction between a released initial position and a clamping position, the hollow piston having a central axial opening.

[0017] Corresponding to the known hollow piston cylinder described at the beginning, the hollow piston cylinder according to the invention also has a tie rod that is anchored in the axial opening of the hollow piston, such that the hollow piston drives the tie rod to move in the axial direction during axial displacement caused by a pressure medium (e.g., hydraulic oil).

[0018] The present invention now specifies that the tie rod is anchored in the axial opening of the hollow piston in a variety of axial positions, thereby allowing flexible adjustment of the functional dimensions of the hollow piston cylinder.

[0019] In one variation of the invention, the desired axial position of the pull rod within the axial opening of the hollow piston can be adjusted in multiple levels. For example, the pull rod can have two different axial positions within the hollow piston, allowing the user to select one of the two axial positions, as will be described in detail below.

[0020] On the other hand, in another variation of the invention, the desired axial position of the pull rod in the axial opening of the hollow piston can be continuously adjusted, making the hollow piston cylinder even more flexible in terms of the desired functional dimensions.

[0021] The first variation of the invention mentioned above will now be described, in which the desired axial position of the pull rod in the axial opening of the piston can be adjusted in stages.

[0022] In this first variation of the invention, the axial opening of the hollow piston has internal threads, similar to the known hollow piston cylinder described at the beginning. Similarly, the pull rod has corresponding external threads that form a screw connection with the internal threads in the axial opening of the hollow piston, anchoring the pull rod within the hollow piston. By tightening the pull rod into the hollow piston to varying degrees, different axial positions of the pull rod relative to the hollow piston can be achieved, resulting in corresponding axial displacements of the pull rod relative to the hollow piston until the pull rod reaches the desired axial position relative to the hollow piston.

[0023] It should be mentioned here that the screw connection between the tie rod and the hollow piston is preferably self-locking, so that the pure axial tensile load on the tie rod will not cause the tie rod to rotate relative to the hollow piston, and therefore the pure axial tensile load on the tie rod will not cause the axial position of the tie rod relative to the hollow piston to be adjusted accordingly.

[0024] In this first variant of the invention, the pull rod has a plurality of locking engagements (e.g., lateral openings) distributed along the pull rod. To lock the pull rod in a desired axial position within the hollow piston, the hollow piston cylinder in the first variant of the invention has a locking element (e.g., a locking bolt) that engages in one of the locking engagements according to the desired axial position of the pull rod, thereby locking the pull rod in the desired axial position.

[0025] In a preferred embodiment of this first variation of the invention, the locking engagements of the pull rod are each of the transverse openings in the pull rod, which preferably penetrate the pull rod radially. For example, the pull rod may have two radially continuous transverse openings that are axially distributed on the pull rod and enable adjustment of two different axial positions of the pull rod relative to the hollow piston.

[0026] The locking element is preferably a locking bolt, which is inserted into a receiving opening in the wall of the hollow piston and then passes through one of the transverse openings located on the pull rod. The locking bolt then prevents the pull rod from rotating relative to the hollow piston, as rotation would cause a corresponding adjustment in the axial position of the pull rod within the hollow piston. In this way, the first variant of the invention can adjust and lock multiple axial positions of the pull rod relative to the hollow piston, the number of possible axial positions being equal to the number of transverse openings.

[0027] It should also be mentioned that the pull ring is preferably attached to one end of the locking bolt so that the locking bolt can be removed manually.

[0028] As mentioned above, the present invention also includes a second variation of the invention, which is capable of continuously adjusting the desired axial position of the pull rod within the axial opening of the hollow piston. Therefore, this second variation of the invention will be described in more detail below.

[0029] Therefore, the second variation of the invention is characterized by a gear set for anchoring the pull rod in an axial opening of the hollow piston at a variety of selectable axial positions.

[0030] In a preferred embodiment of the invention, the gear set for anchoring the pull rod in the hollow piston is multi-stage, having multiple pairs of gears kinetically connected in series. Preferably, the gear set includes a planetary gear set and a screw drive kinetically connected in series.

[0031] The aforementioned planetary gear set preferably has a ring gear as an operating element that can be manually rotated and accessed from the outside. The ring gear has internal teeth and can be rotated by the user to set the desired axial position of the pull rod in the hollow piston, as will be described in detail below.

[0032] Furthermore, the planetary gear set preferably has a centrally located, rotatable sun gear with external teeth.

[0033] Preferably, at least one rotatable gear is positioned between the sun gear and the ring gear. This gear engages with the internal teeth of the ring gear on its outer side and with the external teeth of the sun gear on its inner side, so that the planetary gear set converts the manual rotation of the outer ring gear into the rotational motion of the central sun gear. It should be noted that since the rotation axis of the gear located between the sun gear and the ring gear is fixed in the circumferential direction, the planetary gear set operates in a so-called dual-axis manner.

[0034] As mentioned above, the gear set preferably includes both a planetary gear set and a screw drive. The screw drive is implemented by a sun gear with an axially threaded bore, while the tie rod has an external thread. The external thread of the tie rod and the internal thread of the sun gear then form the screw drive, thereby converting the rotational motion of the sun gear into the axial motion of the tie rod.

[0035] It should be mentioned here that the screw drive is preferably self-locking, so that the axial tensile load on the pull rod will not cause the axial position of the pull rod relative to the hollow piston to be adjusted.

[0036] In this second variation of the invention, the planetary gear set first converts the manual rotation of the ring gear into the rotational motion of the sun gear via the planetary gear set and the screw drive, while the screw drive then converts the rotational motion of the sun gear into the axial motion of the pull rod relative to the hollow piston, so as to set the desired axial position of the pull rod relative to the hollow piston.

[0037] It should be mentioned here that the ring gear is preferably fixed axially relative to the clamping cylinder, just as at least one gear located between the sun gear and the ring gear is fixed axially and circumferentially relative to the clamping cylinder, but is mounted in a rotatable manner.

[0038] On the other hand, the central sun gear is preferably axially supported on the hollow piston and is able to move axially relative to the clamping cylinder together with the hollow piston.

[0039] Preferably, a first spring is provided here, which pretensions the sun gear axially by abutting against the hollow piston, and thus the first spring is preferably designed as a helical spring.

[0040] Furthermore, the pull rod located in the hollow piston is preferably fixed to prevent the pull rod from rotating relative to the hollow piston.

[0041] Therefore, the user can set the desired axial position of the pull rod relative to the hollow piston by rotating the ring gear. To lock the ring gear in the desired rotational position, at least one clamping bolt is preferably provided, which preferably presses against the end face of the ring gear axially. A notch may be located in the end face of the ring gear, whereby at least one clamping bolt then presses into the notch on the ring gear to lock the ring gear in the corresponding rotational position. In a preferred embodiment of the invention, up to six such clamping bolts can be seen pressing against the end face of the ring gear axially to lock the ring gear by a stop connection, wherein three of the six clamping bolts are arranged on each side of the ring gear.

[0042] In the second variation of the invention described above, the hollow piston cylinder preferably has a first housing portion that is securely connected to the clamping cylinder, particularly via a threaded connection. For example, the first housing portion can be screwed into the clamping cylinder. Furthermore, the hollow piston cylinder preferably has a second housing portion that is securely connected to the first housing portion. The ring gear is preferably arranged in a groove between the first and second housing portions and can be accessed from the outside, allowing the user to rotate the ring gear. At least one gear between the sun gear and the ring gear is rotatably mounted on a shaft, wherein the shaft of at least one gear between the sun gear and the ring gear can be mounted in the first housing portion on one side and in the second housing portion on the other side.

[0043] It should also be mentioned that at least one clamping bolt for locking the ring gear can be screwed into an axial opening in the second housing portion.

[0044] The first spring, mentioned above, used to pretension the sun gear axially against the hollow piston, can be supported on the sun gear on one side and on the second housing part on the other side.

[0045] It should also be mentioned that the ring gear may have knurling on its outer surface to facilitate manual rotation by the user.

[0046] In the second variation of the invention described above, the axial opening in the hollow piston preferably has a size that is too large relative to the pull rod, such that the pull rod is indirectly anchored in the hollow piston via a screw connection with the sun gear.

[0047] In addition to the first inventive variant (capable of stepwise adjustment of the axial anchoring position of the pull rod in the hollow piston) and the second inventive variant (capable of stepless adjustment of the axial anchoring position of the pull rod in the hollow piston by means of a planetary gear set), the present invention also includes the third inventive variant as described below.

[0048] In this third variation of the invention, the axial anchoring position of the pull rod located in the hollow piston is also adjusted by means of a gear set. However, the gear set here does not include the multi-stage planetary gear set as in the second variation of the invention, but only a single-stage gear set having only a single pair of meshing teeth. The advantage of this third variation of the invention is that the manufacturing cost is significantly reduced compared to the second variation of the invention which uses a planetary gear set.

[0049] Preferably, in the third variation of the invention, the screw drive includes a rotatable bushing as an operating element, which is arranged in a hollow piston, thus allowing the bushing to rotate relative to the hollow piston, but is axially fixed within it. The bushing has an internal thread that, together with a corresponding external thread on the outer surface of the pull rod, forms the screw drive. This means that, due to the threaded connection between the bushing and the pull rod, the rotational motion of the bushing is converted into a corresponding axial motion of the pull rod. Since the bushing is axially anchored in the hollow piston as described above, the rotational motion of the bushing causes a corresponding change in the axial anchorage position of the pull rod within the hollow piston.

[0050] It should be mentioned here that the screw drive in the third variation of the present invention is preferably self-locking, so that the axial load on the screw drive will not cause the bushing to rotate relative to the tie rod.

[0051] The bushing preferably protrudes axially from the clamping cylinder, allowing the operator to rotate it at that point. To facilitate this rotation by the operator, the bushing preferably has knurled edges on its outer surface at the protruding end. This allows the operator to apply greater torque to the bushing.

[0052] As described above, the rotatable bushing is axially anchored within the hollow piston, such that axial movement of the bushing causes a corresponding axial movement of the hollow piston, and vice versa. To achieve this axial anchoring of the bushing within the hollow piston, the bushing preferably has an annular groove on its outer surface, into which a flat-head screw engages, guided within a radial opening in the hollow piston.

[0053] Furthermore, a third variation of the invention preferably includes a clamping ring to limit the axial adjustment range of the pull rod relative to the hollow piston. The clamping ring is preferably clamped to the pull rod on the clamping side of the hollow piston. For this purpose, the clamping ring preferably has at least one radial opening into which a flat-head screw is screwed, the end of which presses against the circumferential surface of the pull rod, thereby clamping the clamping ring onto the pull rod.

[0054] Furthermore, within the scope of this invention, the corresponding axial position of the pull rod relative to the hollow piston can be displayed on a scale, allowing the user to immediately identify the set functional dimensions. For this purpose, the pull rod preferably protrudes axially from the clamping cylinder opposite the clamping side. At the protruding end of the pull rod, the outer surface of the pull rod has the aforementioned scale, which extends axially and indicates the axial position of the pull rod locked within the hollow piston in the initial position of the released hollow piston. The scale can be directly provided on the pull rod or on an end member screwed to the end of the pull rod.

[0055] It should also be mentioned that the hollow piston cylinder according to the present invention can be a single-acting hollow piston cylinder or a double-acting hollow piston cylinder.

[0056] In the single-acting variant, the hollow piston cylinder has a first pressure medium connection for supplying a pressure medium (e.g., hydraulic oil) to clamp the hollow piston from a released initial position to a clamped position. A second spring (e.g., a coil spring) acting on the hollow piston and pre-tensioning it to the released initial position is used to return the hollow piston from the tensioned position to the released initial position.

[0057] On the other hand, in the double-acting variant, the hollow piston cylinder has two pressure fluid connections for supplying pressure fluid (e.g., hydraulic oil). Therefore, the hollow piston is driven by the pressure medium in two directions (release and clamp).

[0058] It should also be mentioned that the axial opening in the hollow piston is preferably a through hole in the axial direction, which is applicable to both variations of the present invention.

[0059] In addition, it should be mentioned that two variations commonly used in this invention are preferably designed such that the hollow piston cylinder can apply a maximum axial tensile force and / or maximum axial compressive force of at least 1 kN, at least 2 kN, at least 5 kN, at least 10 kN, at least 20 kN, at least 50 kN, at least 100 kN, at least 150 kN, at least 200 kN, or at least 250 kN to the tie rod.

[0060] As mentioned above, the pressure medium used to drive the hollow piston according to the present invention can be hydraulic oil. However, the present invention is not limited to using hydraulic oil as the pressure medium to drive the hollow piston; for example, compressed air can also be used as the pressure medium to drive the hollow piston.

[0061] It should also be mentioned that hollow piston cylinders are preferably designed for operating pressures of at least 20 bar, at least 50 bar, at least 100 bar, at least 200 bar, at least 300 bar, or at least 400 bar.

[0062] The axial position of the pull rod relative to the hollow piston is preferably adjustable within an axial range of at least 10 mm, at least 20 mm, at least 30 mm, at least 50 mm, or at least 100 mm.

[0063] In one embodiment, the hollow piston cylinder has a spherical disc having a flat bearing surface on the clamping side and a convex surface on the opposite side, the clamping cylinder being supported on the convex surface such that the clamping cylinder and the pull rod can perform pivoting motion relative to the spherical disc and the clamping surface.

[0064] In addition, the pull rod has a T-slot screw at its distal end to anchor the pull rod in the T-slot of the part to be clamped.

[0065] Finally, it should also be mentioned that the hollow piston located in the clamping cylinder can have an axial stroke of at least 2 mm, at least 5 mm, or at least 10 mm.

[0066] Other advantageous embodiments of the invention are characterized in the dependent claims, or explained in more detail below with reference to the accompanying drawings and the description of preferred embodiments of the invention. Attached Figure Description

[0067] Figure 1 shows a cross-sectional view of a hollow piston cylinder known from the prior art.

[0068] Figure 2A A perspective view of a hollow piston cylinder according to the present invention, specifically a first variant thereof, is shown.

[0069] Figure 2B The invention is illustrated as follows Figure 2A The diagram shows a cross-sectional view of a hollow piston cylinder.

[0070] Figure 3A A perspective view of a hollow piston cylinder according to the invention, specifically a second variation thereof, is shown.

[0071] Figure 3B As shown Figure 3A The diagram shows a longitudinal cross-sectional view of a hollow piston cylinder.

[0072] Figure 3C As shown Figure 3A as well as Figure 3B The diagram shows a cross-sectional view of a hollow piston cylinder.

[0073] Figure 4 The diagram shows a method using a clamping bolt for locking the ring gear in a rotating position. Figures 3A to 3C A perspective view of the annular gear of the second variant of the present invention.

[0074] Figure 5A A perspective view of a third variant of the invention is shown, comprising a single-stage screw drive for adjusting the axial anchoring position of the pull rod in the hollow piston.

[0075] Figure 5B As shown Figure 5A The side view of the third variant of the invention shown is illustrated.

[0076] Figure 5C It shows that according to Figure 5A as well as Figure 5B The diagram shows a top view of the third variant of the present invention.

[0077] Figure 5D illustrates the third variant of the invention along... Figure 5C The cross-sectional view of section line AA in the diagram. Detailed Implementation

[0078] The first inventive variant of the hollow piston cylinder 1 according to the present invention is described below, such as... Figure 2A and 2B As shown. This variation of the invention largely corresponds to the known hollow piston cylinder 1 as described at the beginning and shown in Figure 1. To avoid repetition, reference is made to the above description of Figure 1, and the same reference numerals are used for the corresponding details.

[0079] The special feature of this embodiment of the present invention is that, in addition to the transverse opening 17, another transverse opening 20 is provided in the tie rod 2, the two transverse openings 17 and 20 are arranged at different axial positions in the tie rod 2, and the transverse openings 17 and 20 each pass through the tie rod 2 radially.

[0080] Therefore, the user can fix the pull rod 2 in two different axial positions in the hollow piston 5 by selecting one of the two transverse openings 17, 20. In the figure, the locking bolt 19 is inserted into the transverse opening 20 located in the pull rod 2, resulting in a relatively small functional size. Here, before locking by means of the locking bolt 19, the desired transverse openings 17, 20 are selected by tightening the pull rod 2 into the hollow piston 5 until the receiving opening 18 on the wall of the hollow piston 5 aligns with the corresponding transverse opening 17 or 19, and then the locking bolt 19 can be inserted.

[0081] Another distinctive feature of this embodiment is that the pull ring 21 is attached to the end of the locking bolt 19, which makes it easier for the user to pull the locking bolt 19 out of the corresponding lateral opening 17 or 20.

[0082] Therefore, the above-described variation of the hollow piston cylinder 1 according to the present invention can be configured with two different functional dimensions by anchoring the locking bolt 19 in the transverse opening 17 or the transverse opening 20.

[0083] The following description is in Figures 3A to 3C The second inventive variant of the hollow piston cylinder 1 according to the invention is shown in Figure 1. This second variant also partially corresponds to the known hollow piston cylinder 1 described at the beginning and shown in Figure 1; therefore, to avoid repetition of the above description, reference is made again to the above description, and the same reference numerals are used for the corresponding details.

[0084] The second variation of the invention is characterized in that the axial position of the pull rod 2 relative to the hollow piston 5 is infinitely adjustable. For this purpose, the second variation of the invention includes a planetary gear set and a screw drive.

[0085] The planetary gear set initially includes an annular gear 22 as an operating element, which can be accessed from the outside and rotated by the user to set a desired axial position, as will be described in detail.

[0086] In addition, the planetary gear includes a central sun gear 23, which is arranged coaxially with the ring gear 22, and the sun gear 23 is also rotatable.

[0087] Between the outer ring gear 22 and the inner sun gear 23 are three gears 24, 25, and 26, each of which is rotatably mounted. The rotation axis of gears 24-26 is thus fixed in the circumferential direction, so that the planetary gear set operates in a so-called dual-axis mode.

[0088] Gears 24-26 are each rotatably mounted on a rotating shaft 27, which is mounted in housing part 28 on one side and housing part 29 on the other.

[0089] Therefore, the planetary gear set converts the rotation of the ring gear 22 by the user into the rotation of the sun gear 23.

[0090] Furthermore, the gear set includes a screw drive component formed by a sun gear 23 and a pull rod 2. For this purpose, the pull rod 2 has an external thread that engages with an internal thread in an axial opening in the sun gear 23. Due to this threaded connection, rotation of the sun gear 23 causes a corresponding axial displacement of the pull rod 2 relative to the hollow piston 5.

[0091] Therefore, the planetary gear set first converts the user's rotation of the ring gear 22 into a corresponding rotational motion of the sun gear 23. Then, the screw drive converts the rotational motion of the sun gear 23 into a corresponding axial motion of the pull rod 2. By rotating the hollow gear 22, the user can thus lock the pull rod 2 in the central piston 5 at the desired axial position.

[0092] It should be mentioned here that the sun gear 23 rests axially on the hollow piston 5, so that the hollow piston 5 carries the sun gear 23 and thus also carries the tie rod 2 which is anchored in the sun gear 23 in the axial direction.

[0093] It should also be mentioned that the end member 30 is screwed onto the end of the pull rod 2, and the end member 30 protrudes from the housing portion 29 in the axial direction, so the end member 30 is visible from the outside. A scale 31 is provided on the outer surface of the end member 30, which allows the user to identify the functional dimension set in the released starting position, as the end member 30 protrudes from the second housing portion 29 by the corresponding length.

[0094] It should also be mentioned that the sun gear 23 is axially movable and is pre-tensioned axially by means of the coil spring 32 in a manner that abuts against the hollow piston 5.

[0095] It should also be mentioned that the ring gear 22 can be locked in the desired rotational position. This is achieved using six clamping bolts 33, which press against the ring gear 22 in the axial direction (see...). Figure 4 Thus, the ring gear 22 has a notch in its end face, in which the clamping bolt 33 engages to lock the ring gear 22 in the desired rotational position. Three of the six clamping bolts are arranged on each side of the ring gear 22.

[0096] Finally, it should also be mentioned that the ring gear 22 has knurling 34 on its outer side surface, which makes it easier for the user to turn the ring gear 22.

[0097] The following description is in Figure 5AThe third variation of the invention is shown in Figure 5D. This third variation of the invention partially corresponds to, as in... Figures 3A to 3C as well as Figure 4 The second variation of the invention described above is shown. To avoid repetition, refer to... Figures 3A to 3C as well as Figure 4 The above description of the second variation of the invention shown, and the use of the same reference numerals for corresponding details, are consistent with the accompanying drawings.

[0098] In this third variation of the invention, the axial anchoring position of the pull rod 2 in the hollow piston 5 is also adjusted steplessly by means of a gear set. However, the gear set here is not based on... Figures 3A to 3C as well as Figure 4 The second variant of the present invention uses a single-stage gear set with a screw drive 35, instead of a multi-stage planetary gear set.

[0099] The screw drive 35 initially includes a rotatable bushing 36, which is coaxially arranged within the hollow piston 5. The rotatable bushing 36 is axially fixed within the hollow piston 5 such that axial movement of the bushing 36 causes a corresponding axial movement of the hollow piston 5, and vice versa. However, since the screw drive 35 is self-locking, axial loads on the screw drive 35 do not cause rotation of the bushing 36 relative to the pull rod 2.

[0100] The bushing 36 has a circumferential annular groove 37 in its outer circumferential surface, into which a flat-head screw 38 engages. The flat-head screw 38 is screwed into a radial opening located in the hollow piston 5. In the position shown in FIG. 5D, the flat-head screw 38 engages with its radially inward end in the annular groove 37 of the bushing 36, thereby fixing the bushing 36 in the hollow piston 5 in the axial direction.

[0101] Furthermore, the bushing 36 has an internal thread that engages with the corresponding external thread of the pull rod 2 and forms a screw drive 35. The screw drive 35 ensures that the rotation of the bushing 36 is converted into corresponding axial movement of the pull rod 2 relative to the bushing 36 and thus relative to the hollow piston 5.

[0102] The lower end of the bushing 36 protrudes from the clamping cylinder 4, and the bushing 36 has knurling 39 to facilitate manual rotation of the bushing 36. The knurling 39 allows the operator to apply greater torque to the bushing 36.

[0103] It should also be mentioned that the pull rod 2 protrudes axially from the bushing 36 and has the aforementioned scale 31, allowing the user to immediately identify the set functional dimensions.

[0104] Furthermore, in this third variation of the invention, a clamping ring 40 is provided, which limits the axial adjustment range of the pull rod 2 relative to the hollow piston 5. The clamping ring 40 surrounds the pull rod 2 in a ring shape on the clamping side of the hollow piston 5. Multiple radial openings are arranged in the clamping ring 40, and flat-head screws 41 are screwed into each radial opening, thereby pressing the flat-head screws 41 into the threads of the outer circumferential surface of the pull rod 2 in the position according to FIG. 5D, thus clamping the clamping ring 40 onto the pull rod 2. Therefore, the pull rod 2 can only be adjusted axially relative to the hollow piston 5 until the clamping ring 40 contacts the upper end face of the hollow piston 5, as shown in FIG. 5D.

[0105] This invention is not limited to the preferred embodiments described above. Rather, it includes variations and modifications that also utilize the inventive concept and therefore fall within the scope of protection. In particular, this invention also claims protection for the subject matter and features of the dependent claims, which are independent of the claims involved in each case, and specifically, those dependent claims that lack the features of the main claim. Therefore, this invention includes various aspects of the invention, which are independently protected.

[0106] Figure Labels 1: Hollow piston cylinder 2: Pull rod 3: T-slot head of the pull rod 4: Clamping cylinder 5: Hollow piston 6: Seals located on the outer surface of the hollow piston 7, 8: Seals on the running surface of the clamping cylinder 9: The screw connection between the hollow piston and the tie rod 10: Spherical disk-shaped component 11: Contact surface of spherical disc-shaped component 12: Spherical surface of a spherical disk-shaped component 13: Hydraulic connectors used for clamping hollow piston cylinders 14: Pressure chamber of clamping cylinder 15: A coil spring used to release the hollow piston cylinder. 16: Shell-shaped container 17: A transverse opening located in the tie rod 18: Receiving opening in the hollow piston for the locking bolt 19: Locking bolt 20: Lateral opening in the tie rod 21: Pull ring for pulling out the locking bolt 22: The ring gear of a helical gearbox 23: The sun gear of a helical gearbox 24-26: Gears in a helical gearbox between the ring gear and the sun gear. 27: The shaft of the gear 28: The housing portion on the clamping cylinder 29: The housing portion on the clamping cylinder 30: Pull rod end component 31: Scale used to display the size of the setting function. 32: A coil spring used to pretension the sun gear against a hollow piston. 33: A clamping bolt used to lock the ring gear in the stopped position. 34: Knurling 35: Screw drive components 36: Bushing 37: Annular groove 38: Flathead screw 39: Knurling on the outer surface of the bushing 40: Clamping ring 41: Flat-head screw located on the clamping ring.

Claims

1. A hollow piston cylinder (1) for clamping a component, particularly, the component being a tool or workpiece, the hollow piston cylinder (1) comprising: a) Clamping cylinder (4) b) A hollow piston (5), which can be driven in the clamping cylinder (4) by a pressure medium, thereby being able to move axially between a released starting position and a clamping position, and the hollow piston (5) has a central axial opening, and c) A pull rod (2) protrudes from the clamping cylinder (4) on the clamping side and is anchored in the axial opening of the hollow piston (5) such that the hollow piston (5) drives the pull rod (2) in the axial direction when axial displacement is generated by the pressure medium. Its features d) The pull rod (2) can be anchored in the axial opening of the hollow piston (5) at various axial positions.

2. The hollow piston cylinder (1) according to claim 1, characterized in that, a) The desired axial position of the pull rod (2) in the axial opening of the hollow piston (5) can be adjusted in multiple levels, or b) The desired axial position of the pull rod (2) in the axial opening of the hollow piston (5) can be continuously adjusted.

3. The hollow piston cylinder (1) according to any one of the preceding claims, characterized in that, a) The axial opening of the hollow piston (5) has an internal thread. b) The pull rod (2) has external threads. c) The external thread of the pull rod (2) and the internal thread of the axial opening of the hollow piston (5) form a screw connection part (9), which anchors the pull rod (2) in the hollow piston (5). d) The screw connection (9) allows the pull rod (2) to be in different axial positions relative to the hollow piston (5) by tightening the pull rod (2) into the hollow piston (5) to different degrees. e) Preferably, the screw connection (9) between the pull rod (2) and the hollow piston (5) is self-locking, such that a pure axial tensile load on the pull rod (2) will not cause the pull rod (2) to rotate relative to the hollow piston (5) and therefore will not cause a corresponding adjustment in the axial position of the pull rod (2) relative to the hollow piston (5).

4. The hollow piston cylinder (1) according to claim 3, characterized in that, a) The pull rod (2) has a plurality of locking engagements (17, 20) distributed along the pull rod (2), and b) A locking element (19) is provided for locking the pull rod (2) in the hollow piston (5) at one of the multiple axial positions, the locking element (19) engaging in one of the locking engagements (17, 20) of the pull rod (2) according to the desired axial position of the pull rod (2).

5. The hollow piston cylinder (1) according to claim 4, characterized in that, a) Each of the locking engagements (17, 20) of the pull rod (2) is a transverse opening (17, 20) in the pull rod (2), preferably, the transverse opening (17, 20) extends radially through the pull rod (2). b) The locking element (19) is a locking bolt (19). c) The hollow piston (5) has a receiving opening (18) on its wall for the locking bolt (19), and d) The locking bolt (19) for locking the pull rod (2) in one of the axial positions is inserted into the receiving opening (18) located on the wall of the hollow piston (5), and the locking bolt (19) passes through one of the transverse openings (17, 20) in the pull rod (2). e) A pull ring (21) is attached to one end of the locking bolt (19) so that the locking bolt (19) can be manually removed.

6. The hollow piston cylinder (1) according to claim 1 or 2, characterized in that, The hollow piston cylinder has a gear set for anchoring the tie rod (2) in an axial opening of the hollow piston (5) at a variety of selectable axial positions.

7. The hollow piston cylinder (1) according to claim 6, characterized in that, a) The gear set is multi-stage, having multiple pairs of gears (22-26) kinetically connected in series, and / or b) The gear set has a planetary gear set (22-26) and a screw drive (23, 2), which are kinetically connected in series.

8. The hollow piston cylinder (1) according to claim 7, characterized in that, a) The planetary gear set (22-26) has a ring gear (22) as an operating element that can be manually rotated and accessed from the outside, the ring gear (22) having internal teeth, b) The planetary gear set (22-26) has a centrally located and rotatable sun gear (23), which has external teeth. c) The planetary gear set (22-26) has at least one rotatable gear (24-26), which engages externally with the internal teeth of the ring gear (22) and internally with the external teeth of the sun gear (23), and d) The planetary gear set (22-26) converts the manual rotation of the outer ring gear (22) into the rotational motion of the central sun gear (23).

9. The hollow piston cylinder (1) according to claim 8, characterized in that, a) The sun gear (23) has an axial opening with internal threads. b) The pull rod (2) has external threads. c) The external thread of the pull rod (2) engages with the internal thread of the sun gear (23), so that the pull rod (2) and the sun gear (23) form the screw drive, which converts the rotational motion of the sun gear (23) into the axial motion of the pull rod (2). d) Preferably, the screw drive is self-locking, so that the axial tensile load on the pull rod (2) will not cause the axial position of the pull rod (2) relative to the hollow piston (5) to be adjusted.

10. The hollow piston cylinder (1) according to claim 9, characterized in that, a) The planetary gear set (22-26) converts the manual rotation of the ring gear (22) into the rotational motion of the sun gear (23), and b) The screw drive converts the rotational motion of the sun gear (23) into the axial motion of the pull rod (2) relative to the hollow piston (5) in order to set the desired axial position of the pull rod (2) relative to the hollow piston (5).

11. The hollow piston cylinder (1) according to any one of claims 8 to 10, characterized in that, a) The ring gear (22) is axially fixed relative to the clamping cylinder (4), and / or b) At least one of the gears (24-26) is mounted between the sun gear (23) and the ring gear (22) so as to be fixed in the axial and circumferential directions relative to the clamping cylinder (4) and rotatable, and / or c) The sun gear (23) is axially supported on the hollow piston (5), and the sun gear (23) is axially displaceable relative to the clamping cylinder (4) together with the hollow piston (5), and / or d) A first spring (32) pretensions the sun gear (23) by abutting the hollow piston (5) axially. In particular, the first spring (32) is a first helical spring (32), and / or e) The pull rod (2) is fixed in the hollow piston (5) to prevent the pull rod (2) from rotating relative to the hollow piston (5).

12. The hollow piston cylinder (1) according to any one of claims 8 to 11, characterized in that, a) At least one clamping bolt (33) is configured to lock the annular gear (22) in the corresponding rotational position. b) Preferably, the at least one clamping bolt (33) presses axially against the end face of the annular gear (22), and c) Preferably, the end face of the ring gear (22) has a circumferential notch, and the at least one clamping bolt (33) is pressed into the notch on the ring gear (22) to lock the ring gear (22) in the corresponding rotational position.

13. The hollow piston cylinder (1) according to any one of claims 8 to 12, characterized in that, a) The hollow piston cylinder (1) has a first housing portion (28) which is securely connected to the clamping cylinder (4). In particular, the first housing portion (28) is securely connected to the clamping cylinder (4) by a threaded connection, which has an internal thread in the clamping cylinder and an external thread on the first housing portion (28), such that the first housing portion (28) is screwed into the clamping cylinder (4), and / or b) The hollow piston cylinder (1) has a second housing portion (29) which is securely connected to the first housing portion (28), and / or c) The ring gear (22) is arranged in a groove between the first housing portion (28) and the second housing portion (29), and the ring gear (22) is accessible from the outside, and / or d) The at least one gear (24-26) located between the sun gear (23) and the ring gear (22) is rotatably mounted on the shaft (27), and / or e) The shaft (27) of at least one gear (24-26) located between the sun gear (23) and the ring gear (22) is mounted in the first housing portion (28) on one side and in the second housing portion (29) on the other side, and / or f) The clamping bolt (33) for locking the ring gear (22) is tightened into an axial opening located in the second housing portion (29), and / or g) The first spring (32) for axially pretensioning the sun gear (23) against the hollow piston (5) is supported on the sun gear (23) on one side and on the second housing portion (29) on the other side, and / or h) The ring gear (22) has knurling (34) on its outer side surface to facilitate manual rotation of the ring gear (22), and / or i) The axial opening in the hollow piston (5) is too large relative to the pull rod (2), so that the pull rod (2) is indirectly anchored in the hollow piston (5) via the screw connection with the sun gear (23).

14. The hollow piston cylinder (1) according to claim 6, characterized in that, a) The gear set is a single-stage screw drive (35), which converts the rotational motion of the bushing (36) as the operating element into the axial motion of the pull rod (2) relative to the hollow piston (5). b) Preferably, the screw drive (35) is self-locking, such that axial loads on the screw drive (35) do not cause rotational movement of the bushing (36) relative to the tie rod (2) and therefore do not cause axial relative movement of the tie rod (2) relative to the bushing (36).

15. The hollow piston cylinder (1) according to claim 14, characterized in that, a) The bushing (36) is arranged in the hollow piston (5), and the bushing (36) is used to adjust the axial anchoring position of the pull rod (2) in the hollow piston (5). b) The bushing (36) is rotatable relative to the hollow piston (5) to adjust the axial anchoring position of the pull rod (2) in the hollow piston (5). c) The bushing (36) is axially fixed within the hollow piston (5), thereby preventing axial relative movement of the bushing (36) relative to the hollow piston (5). d) The bushing (36) has internal threads, e) The tie rod (2) has external threads on its side surface. f) The bushing (36) engages with the external thread of the pull rod (2) through its internal thread to form a screw drive (35), such that the rotational movement of the bushing (36) changes the axial position of the pull rod (2) relative to the bushing (36), thereby also changing the axial position of the pull rod (2) relative to the hollow piston (5). g) Preferably, the bushing (36) protrudes from the clamping cylinder (4) in the axial direction and has knurling (39) on the outer circumferential surface of the bushing (36).

16. The hollow piston cylinder (1) according to claim 15, characterized in that, a) The bushing (36) has an annular groove (37) on its outer circumferential surface. b) The hollow piston (5) has a threaded radial opening, and c) A flat-head screw (38) is screwed into the radial opening of the hollow piston (5), the flat-head screw (38) engaging the annular groove (37) on the outer circumferential surface of the bushing (36) through the radially inner end of the flat-head screw, thereby fixing the bushing (36) axially in the hollow piston (5).

17. The hollow piston cylinder (1) according to any one of claims 14 to 16, characterized in that, a) A clamping ring (40) is provided to limit the axial adjustment range of the pull rod (2) relative to the hollow piston (5). b) The clamping ring (40) is clamped onto the pull rod (2). c) Preferably, the clamping ring (40) for clamping the pull rod (2) has a threaded radial opening, and a flat-head screw (41) is screwed into the radial opening. The flat-head screw (41) is pressed against the outer circumferential surface of the pull rod (2) by its radially inward end, thereby clamping the clamping ring (40) onto the pull rod (2). d) Preferably, the clamping ring (40) is clamped on the pull rod (2) on the clamping side of the hollow piston (5).

18. The hollow piston cylinder (1) according to any one of the preceding claims, characterized in that, a) The pull rod (2) protrudes axially from the clamping cylinder (4) in a manner opposite to the clamping side, and b) The pull rod (2) has a scale (31) on its outer circumferential surface at the end of the pull rod that protrudes from the clamping cylinder (4) in a manner opposite to the clamping side. The scale extends in the axial direction and indicates the axial position in which the pull rod (2) is locked in the hollow piston (5) in the released initial position of the hollow piston (5). c) Preferably, the scale (31) is provided on the side surface of the end member (30), which is screwed onto the end of the pull rod (2).

19. The hollow piston cylinder (1) according to any one of the preceding claims, characterized in that, a) The hollow piston cylinder (1) is a single-acting type, and the hollow piston cylinder has: a1) A first pressure medium connector (13) for supplying the pressure medium for clamping the hollow piston (5) from the released initial position to the clamping position, and a2) A second spring, the second spring being used to return the hollow piston (5) from the clamping position to the released initial position, specifically, the second spring being a second helical spring, preferably, the second spring being supported on the hollow piston (5) on one side and on the first housing portion on the other side, or b) The hollow piston cylinder (1) is a double-acting type, and the hollow piston cylinder has: b1) A first pressure medium connector (13) for supplying the pressure medium for clamping the hollow piston (5) from the release starting position to the clamping position, and b2) A second pressure medium connector, which is used to supply pressure medium for resetting the hollow piston (5) from the clamping position to the released starting position.

20. The hollow piston cylinder (1) according to any one of the preceding claims, characterized in that, a) The axial opening located in the hollow piston (5) is a continuous through opening in the axial direction, and / or b) The hollow piston cylinder (1) is designed to apply a maximum axial tensile force and / or a maximum axial compressive force of at least 1 kN, at least 2 kN, at least 5 kN, at least 10 kN, at least 20 kN, at least 50 kN, at least 100 kN, at least 150 kN, at least 200 kN, or at least 250 kN to the tie rod (2), and / or c) The pressure medium is hydraulic oil or compressed air, and / or d) The hollow piston cylinder (1) is designed for operating pressures of at least 20 bar, at least 50 bar, at least 100 bar, at least 200 bar, at least 300 bar, or at least 400 bar, and / or e) The axial position of the pull rod (2) relative to the hollow piston (5) can be adjusted within an axial range of at least 10 mm, at least 20 mm, at least 30 mm, at least 50 mm, or at least 100 mm, and / or f) The hollow piston cylinder (1) has a spherical disc (10) having a flat clamping surface (11) on the clamping side, and a convex surface (12) on the opposite side, the clamping cylinder (4) abutting against the convex surface (12), such that the clamping cylinder (4) can pivot relative to the pull rod (2) with respect to the spherical disc (10) and the clamping surface (11), and / or g) The pull rod (2) has a T-slot screw at its distal end to anchor the pull rod (2) in the T-slot of the component to be clamped, and / or h) The hollow piston (5) located in the clamping cylinder (4) has an axial stroke of at least 2 mm, at least 5 mm or at least 10 mm, and in particular, the hollow piston (5) located in the clamping cylinder (4) has an axial stroke of 12 mm.

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