LOCKING DEVICE OF A GRIPPING OR CLAMPING DEVICE

Description

[0001] The invention relates to a locking device for a gripping or clamping device having two base jaws movable towards and away from each other, with a coupling element rotatably arranged about an axis of rotation and coupled or capable of being coupled to the base jaws, wherein the coupling element has a braking section on its outer surface, and with at least one braking element which can be moved from a release position into a locking position along a locking direction perpendicular to the axis of rotation in order to lock the coupling element. The invention also relates to a gripping or clamping device with such a locking device.

[0002] Various types of locking devices are known from DE 10 2019 103 916 A1. Figures 12a and 12b show a locking device that exhibits features of the preamble of claim 1. Two opposing brake elements in the form of brake shoes are provided, which act against a braking section formed by the outer surface of a brake disc. The brake shoes can be moved from the release position to the locking position along the locking direction along a common line that is perpendicular to and intersects the axis of rotation – i.e., radial to the braking section.

[0003] From DE 10 2017 124 720 A1 another fixing device for a gripping or clamping device is known.

[0004] Gripping or clamping devices without a braking and / or locking unit are known, for example, from DE 100 13 022 C2 or DE 101 38 685 C1.

[0005] Furthermore, DE 2011 084 177 A1 discloses the provision of a damping element between the drive of the gripping jaw and the gripping jaw itself. DE 10 2013 211 528 A1 discloses the provision of an elastic spring element for maintaining gripping force.

[0006] From DE 10 2019 118 672 B3, a gripping or clamping unit with a gear arrangement for maintaining a gripping force is known. The gripping force is maintained by tensioning a spring over the travel distance of the gripping jaws, whereby the gripping jaws cannot be locked without a clamped / gripped object.

[0007] A fixing device according to the preamble of claim 1 is known from DE 10 2005 060511 A1.

[0008] The invention is based on the objective of providing a locking device and an associated gripping or clamping unit that is compact and with which the jaws can be braked and locked in a simple and reliable manner.

[0009] This problem is solved by a fixing device with the features of claim 1.

[0010] Consequently, it is specifically provided that the braking element engages the braking section tangentially when moved into the locking position. Due to this tangential engagement, the locking direction runs along a straight line, preferably spaced at least by the radius of the braking section from the axis of rotation. Unlike the prior art according to DE 10 2019 103 916 A1, the braking element does not act radially against the braking section, but tangentially. This allows for a compact locking device, since the braking element engages tangentially, i.e., laterally, on the coupling member or its braking section. Furthermore, unlike the prior art embodiment, the braking element can still be moved, at least to a limited extent, into the locking device even during or while interacting with the braking section.

[0011] It is advantageous if the braking section is designed as a pinion and if the braking element has a rack section that interacts with the pinion in the locked position and engages tangentially with the pinion. Such a rack section has at least one tooth with a tooth head that releases the pinion in the release position and interacts with the pinion in the locked position, thus locking the pinion and, consequently, the coupling element. It is conceivable that the rack section could also have two or more teeth. In particular, by providing the pinion and the rack, a positive locking of the pinion, and thus of the coupling element, can be achieved.

[0012] It has proven particularly advantageous to use two rack sections and to have an odd number of teeth on the pinion, selected so that only one of the two rack teeth can engage with each tooth of the pinion at any given time. This ensures that, in every position of the pinion, a positive engagement of one or the other rack is possible between two teeth of the pinion. Should the pinion be in such a position that one of the two racks engages a tooth of the pinion and therefore cannot engage positively, the other rack can engage positively and lock the pinion in place.Advantageously, the design is further such that the rack engaging with the pinion rotates the pinion at least enough to allow the other rack to engage between two teeth of the pinion, so that ultimately both racks lock the pinion, and thus the coupling element.

[0013] Furthermore, it is advantageous if the braking section is designed as a circular cylinder surface and if the braking element engages tangentially with the circular cylinder surface in the locked position. Depending on the selection of suitable materials, appropriate coefficients of friction are achieved, ensuring secure locking in the locked position. In particular, this allows for a force-fit and / or friction-fit locking of the coupling element.

[0014] The braking element can preferably be designed as a wedge finger, which has a wedge surface extending obliquely to the locking direction and acting tangentially against the braking section in the locking position. By providing the wedge surface and by selecting a suitable wedge angle, force amplification can be achieved when moving the wedge finger into the locking position.

[0015] Furthermore, it is conceivable that the braking element is designed as a wedge fork with two wedge surfaces running obliquely to the locking direction and acting tangentially against the braking section in the locking position. Such a wedge fork consequently comprises two wedge fingers that are moved synchronously into the respective locking position. Both wedge surfaces of the wedge fork then engage the braking section symmetrically and tangentially. This allows for a higher locking force to be achieved than with only one wedge finger.

[0016] Furthermore, it is conceivable that the braking element is designed as a wedge fork with two wedge surfaces running obliquely to the locking direction and acting tangentially against the braking section in the locking position. Such a wedge fork consequently comprises two wedge fingers that are moved synchronously into the respective locking position. Both wedge surfaces of the wedge fork then engage the braking section symmetrically and tangentially. This allows for a higher locking force to be achieved than with only one wedge finger.

[0017] Furthermore, it has proven advantageous if the wedge surfaces are designed in such a way that they are elastically deflected into their final locking position when engaging the brake section and during further movement along the locking direction. This allows the wedge surfaces to bear against the brake element under preload, ensuring secure locking of the coupling element even in the presence of manufacturing tolerances.

[0018] It is advantageous if at least one recess for creating a solid-body joint is provided on the side of the wedge finger or wedge fork facing away from the respective wedge surface. The recess can be geometrically designed such that the desired elastic compliance for fixing the coupling element is achieved by the solid-body joint formed by the recess.

[0019] Furthermore, it is advantageous to provide two braking elements that are arranged point-symmetrically with respect to the axis of rotation or mirror-symmetrically with respect to a plane perpendicular to the fixing direction. Such a symmetrical arrangement allows for secure fixing of the coupling element while requiring minimal installation space.

[0020] The locking device according to the invention further advantageously provides that at least one brake piston and at least one spring element cooperating with the brake piston are provided, wherein the displacement of the brake element from the release position to the locking position occurs due to the spring force of the spring element, and wherein the brake piston defines a pressure chamber such that, when the pressure chamber is pressurized, the brake element is forced from the locking position into the release position against the spring force of the spring element. To better utilize the installation space, it can also be provided that the at least one brake piston is arranged to be displaceable laterally next to the coupling member, parallel to the axis of rotation.

[0021] In this context, it has proven advantageous to arrange a first, smaller brake piston and a second, larger brake piston on a piston rod, each defining a pressure chamber. The larger brake piston faces the spring element, and the smaller brake piston faces away from it. An intermediate wall is provided between the brake pistons, defining the pressure chamber of the larger brake piston. The two pressure chambers are preferably pressurized. This allows for force amplification to actuate the respective brake element, as two brake pistons with a corresponding effective surface are available to move the respective brake element into its fixed position and ultimately to generate the braking force.

[0022] In this context, it is advantageous if the partition wall is supported against a housing stop on the side facing away from the larger piston. Such a housing stop can be designed as a circumferential housing shoulder. When the respective pressure chambers are pressurized, the partition wall is then pressed against the housing stop, thus providing support. In the event of a pressure loss and when the spring force is applied to the larger brake piston, the partition wall is also pressed against the housing stop. The partition wall can advantageously provide a sealed recess for the passage of the piston rod. Due to such an arrangement of the partition wall, fastening elements for the partition wall itself can essentially be eliminated, resulting in a comparatively simple design.

[0023] The aforementioned problem is also solved by a gripping or clamping device comprising a locking device according to the invention. The locking device can be attached to the gripping or clamping device as an add-on module or be integrated into the gripping or clamping device.

[0024] The gripping or clamping device according to the invention can further provide two base jaws that can be moved towards and away from each other, wherein each base jaw is coupled to at least one working piston that defines a working pressure chamber, and wherein each working piston has a coupling section that is coupled to a coupling element rotatably arranged about an axis of rotation, the coupling element of the gripping or clamping device simultaneously forming the coupling element of the locking device or being rotatably coupled to it. With such a gripping or clamping device, the base jaws are thus pneumatically driven via the working pistons. By providing the coupling element, the movement of the working pistons can be locked by means of the locking device.

[0025] This has the further advantage that the position of the braking section is maintained in the locked position, and consequently, the position of the gripping jaws of the gripping device can also be fixed independently of a gripped object. This also prevents the jaws from snapping shut, which increases the operational safety of the gripping device. If a gripped object is removed from the gripping device while the locking mechanism is in its locked position, the snapping of the gripping jaws poses a risk of injury, as is the case in the prior art described in DE 10 2019 118 672 B3.

[0026] Further details and advantageous embodiments of the invention can be found in the following description, which provides further description and explanation of exemplary embodiments of the invention.

[0027] They show: Figure 1 shows a longitudinal section through a fixing device according to the invention, which is provided on a gripping device; Figure 2 shows a cross-section through the fixing device according to the invention. Figure 1 Figure 3: an enlarged representation of the in Figure 2 shown pinion; Figure 4 one of the Figure 1 corresponding longitudinal section through a second fixing device according to the invention; Figure 5 a cross-section through the fixing device according to Figure 3 Figure 6 shows an enlarged view of section VI in Figure 5 Figure 7, one of the Figure 1 corresponding longitudinal section through a third fixing device according to the invention; and

[0028] Figure 8 a cross-section through the in Figure 5 shown fixing device.

[0029] In the Figure 1A locking device 10 is shown, which is arranged on a gripping device 12. The gripping device 12 is shown only schematically and has two base jaws 14 that can move towards and away from each other. Furthermore, the gripping device 12 has a coupling element 22 that is motionally coupled to the base jaws 14 and rotatably arranged about a pivot axis 24. In the Figure 1The gripping device 12 shows two working pistons 16, each coupled to one of the base jaws 14. A movement of the working pistons 16 consequently results in a movement of the base jaws 14. The working pistons 16, or rather their piston rods 18, each have a coupling section 20, which is coupled to a coupling element 22 rotatably arranged about the axis of rotation 24. Moving the pistons 16 towards or away from each other therefore causes the coupling element 22 to rotate about the axis 24. The movements of the two working pistons 16, and thus the movements of the base jaws 14, are synchronized via the coupling element 22.

[0030] The coupling element 22 can be designed as a pinion in the area where it interacts with the coupling sections 20. The piston sections 20 of the piston rods 18 can then be designed as meshing racks for the pinion.

[0031] The one in Figure 1 The gripping device shown can in particular be the one described in DE 10 2019 103 916 A1, in the Figures 1 to 6 , shown gripping devices. For further details and operating principles of gripping device 12, please refer to the Figures 1 to 6 with reference to the associated description of the aforementioned document.

[0032] As can be seen from the section according to Figure 1 As is evident, the locking device 10 is designed as an add-on module that can be attached to the gripping device 12. This has the advantage that the gripping device 12 can also be operated without the locking device 10.

[0033] From the section according to Figure 1It becomes clear that the fixing device 10 has its own coupling element 26 rotatably mounted in its housing 11, which is rotatably coupled to the coupling element 22 of the gripping device 12 via a coupling section 28. In this context, it is conceivable that instead of two separate coupling elements 22, 26, a common coupling element can also be used, which is in particular designed as a single piece.

[0034] The coupling element 26 of the fixing device 10 has a braking section 30 on its outer surface, which in the embodiment according to Figures 1 and 2 is designed as a pinion 32. To fix the brake section 30 or the pinion 32, as shown in the diagram... Figures 1 and 2 It becomes clear that two brake elements 34 are provided. In the embodiment according to Figures 1 and 2The brake elements 34 each have a rack section 36 with teeth 42, which are designed to interact with the pinion 32 and lock it in its position. The brake elements 34 can be moved from a retracted release position along a locking direction 38 perpendicular to the axis of rotation 24 into a locked position.

[0035] The rack sections 36 engage tangentially with the brake section 30 or the pinion 32 in the fixed position. As shown from Figure 2 As becomes clear, the fixing directions 38 each run along a straight line that is spaced from the axis of rotation 24 by the radius or the pitch circle radius r of the pinion 32. For illustration, the left half of the Figures 1 and 2 the left brake element 34 in the fixed position; in the right half of the Figures 1 and 2 The right brake element 34 is in the release position.

[0036] The pinion 32 has an odd number of teeth (44). This has, as can be seen from Figure 3 It becomes clear that when moving the brake elements 34 into the fixed position, if anything, only one tooth 42 of a rack 36 meets a tooth head of a tooth 44 of the pinion 32 ( Figure 3 , left image). This ensures that one of the two rack sections 36 is always engaged with the pinion 32 in order to lock it or the coupling link 26, and thus ultimately the base jaws 14 ( Figure 3 , right image).

[0037] What's next? Figure 2 As can be clearly seen, the two brake elements 34 are arranged symmetrically with respect to the axis of rotation 24. This has the advantage that both brake elements 34 act symmetrically on the brake section 30.

[0038] The brake elements 34 are each coupled to two brake pistons 48, 50. The brake pistons 48, 50 each define a pressure chamber 52, 54, which are arranged such that when the pressure chambers 52, 54 are pressurized, the pistons 48, 50 move in the direction away from the pinion 26, thereby moving the brake elements 34 into their release position. Figure 1 Spring elements 58 are provided between the brake piston 50 and a housing cover 56, which force the brake piston 50 towards the pinion 32, and thus the brake element 34 into the fixed position (in Figure 2 (The spring elements 58 are not shown for clarity). If a pressure drop occurs in the pressure chambers 52, 54, the brake pistons 48 and 50, and thus the respective brake element 34, are moved by the spring elements 58 into the locking position, as shown in the left half of the locking device in Figures 1 and 2As shown, it is moved into the fixed position. With sufficient pressure applied to the pressure chambers 52, 54, the two pistons 48, 50 are moved, as shown in the right half of the Figures 1 and 2 As shown, the respective brake element 34 is forced from the locked position into the release position. The pressure chambers 52, 54 are connected to the same pressure source as the pressure chambers delimited by the drive pistons 16; in the event of a particularly unwanted pressure drop, the brake elements 34 are forced into the locked position by the spring elements 58 and the gripping jaws 14 are locked.

[0039] The two corresponding brake pistons 48 and 50 are connected to each other via a piston rod 60. Furthermore, an intermediate wall 62 in the form of a piston disc is provided between the corresponding brake pistons 48 and 50. The respective piston rod 60 passes through the respective intermediate wall 62 in a pressure-sealed manner.

[0040] The intermediate walls 62 are each supported on the side facing away from the larger brake piston 50 by a housing stop 64. The housing stop is designed as a circumferential annular shoulder. This design has the advantage that the intermediate walls 62 can be inserted into the housing stop 64 without any additional fastening means. When the pressure chambers 52 and 54 are pressurized, the pressure in the pressure chamber 54 forces the respective intermediate wall 62 against the housing stop 64. When the pressure in the pressure chambers 52 and 54 drops, the spring elements 58 force the respective intermediate wall 62 against the respective housing stop 64.

[0041] The one in Figures 4 and 5 The locking device 70 shown essentially corresponds to the one described in the Figures 1 and 2 The locking device 10 shown, where corresponding components are marked with corresponding reference numerals. Unlike the locking device 10, the locking device 70 is designed for a [missing information] in the Figures 4 and 5A gripping device not shown and a common coupling element 26 are provided for the fixing device 70.

[0042] The locking device 70 further differs from the locking device 10 in that the braking section 30 is not designed as a pinion, but as a rotationally symmetrical cylindrical surface, and in the illustrated embodiment as a circular cylindrical surface 72. According to the Figure 2 are in the Figures 3 and 4Spring elements 58 between the housing covers 56 and the respective outer brake pistons 50 are not shown. Furthermore, in the locking device 70, the brake elements 34 are not designed as rack sections, but as wedge fingers 74. The wedge fingers 74 each have a wedge surface 76 that extends obliquely to the locking direction 38 and forms an acute angle with the locking direction 38. Consequently, when the brake elements 34 are moved in the locking direction 38, the wedge surfaces 76 of the brake elements 34 engage tangentially with the brake section 30 or the circular cylinder surface 72.

[0043] As can be seen from the enlarged section according to Figure 6As can be clearly seen, the wedge fingers 74 have a recess 78 on the side facing away from the wedge surfaces 76, so that the wedge surfaces 76 and the wedge fingers 74 are deflected elastically when they engage the braking section 30 and when they continue to move along the fixing direction 38. The recess 78 thus creates a type of rigid joint. To allow the free end of the wedge finger 74 to deflect, the section of the respective wedge finger 74 located between the free end and the recess 78 is offset back towards the braking section 30 by a distance 79.

[0044] According to the locking device 10, in the case of the locking device 70, when the pressure drops in the pressure chambers 52, 54, the two brake elements 34, or rather their wedge surfaces 76, are locked due to the pressure in the Figures 4 and 5spring elements not shown, are mounted from their release position along the fixing direction 38 into the fixed position; the wedge surfaces 76 engage tangentially, force-fit on the coupling member 26 or its braking section 30.

[0045] In the Figures 7 and 8 A further fixing device 80 according to the invention is shown, which is essentially the fixing device 70 according to Figures 4 and 5 corresponds, with corresponding components bearing corresponding reference symbols.

[0046] In contrast to the locking device 70, the locking device 80 has two wedge forks 82 as braking elements 34, each with two wedge fingers 74 having wedge surfaces 76 extending obliquely to the locking direction 38. The locking device 80 therefore engages the braking section 30 not with just two wedge surfaces 76, but with a total of four wedge surfaces 76. This allows for an increased locking effect. Corresponding to the locking device 70, recesses 78 are provided on the wedge forks 82, or on each wedge finger 74 of a wedge fork 82, to allow the respective wedge fingers 74 to deflect elastically, as required by the locking device 70.

Claims

1. Locking device (10, 70, 80) of a gripping or clamping apparatus (12) having two sliding jaws (14) that can be moved toward and away from one another, the locking device comprising a coupling member (26) which is motion-coupled or can be motion-coupled to the sliding jaws (14) and is rotatably arranged about an axis of rotation (24), the coupling member (26) having a brake portion (30) on the lateral surface thereof, and the locking device comprising at least one brake element (34) which can be moved from a release position in a locking direction (38) extending perpendicularly to the axis of rotation (24) into a locking position in order to lock the coupling member (26), characterized in that the brake element (34) engages tangentially on the brake portion (30) when it is moved into the locking position.

2. Locking device (10) according to claim 1, characterized in that the brake portion (30) is designed as a pinion (32) and in that the brake element (34) has a toothed rack portion (36) which interacts with the pinion (32) in the locking position and engages tangentially on the pinion (32).

3. Locking device (10) according to claim 2, characterized in that two toothed rack portions (36) are provided and in that the pinion (32) has an odd number of teeth which is selected such that only one of the two toothed rack portions (36) can strike one tooth head (44) of the pinion (32) in each case.

4. Locking device (70, 80) according to claim 1, characterized in that the brake portion (30) is designed as a rotationally symmetrical lateral surface (72) and in that the brake element (34) engages tangentially on the lateral surface (72) in the locking position.

5. Locking device (10, 70, 80) according to claim 1 or 4, characterized in that the brake element (34) is designed as a wedge finger (74) having a wedge surface (76) extending obliquely to the locking direction (38) and acting tangentially against the brake portion (30) in the locking position.

6. Locking device (70, 80) according to claim 5, characterized in that the brake element (34) is designed as a wedge fork (82) having two wedge surfaces (76) extending obliquely to the locking direction (38) and acting tangentially against the brake portion (30) in the locking position.

7. Locking device (70, 80) according to any of claims 5 or 6, characterized in that the wedge surfaces (76) are designed such that they are elastically flexibly deflected when engaging the brake portion (30) and during further movement in the locking direction (38).

8. Locking device (70, 80) according to claim 7, characterized in that have a recess (78) for implementing a flexure bearing on the side facing away from the respective wedge surfaces (76).

9. Locking device (10, 70, 80) according to any of the preceding claims, characterized in that two brake elements (34) are provided, which are arranged point-symmetrically with respect to the axis of rotation (24) or mirror-symmetrically with respect to a plane extending perpendicularly to the locking direction.

10. Locking device (10, 70, 80) according to any of the preceding claims, characterized in that at least one brake piston (46, 48) and at least one spring element (58) interacting with the brake piston (46, 48) are provided, the brake element (34) moving from the release position into the locking position due to the spring force of the spring element (58), and the at least one brake piston (46, 48) delimiting a pressure chamber (52, 54) in such a way that, when the pressure chamber (52, 54) is pressurized, the brake element (34) is forced from the locking position into the release position counter to the spring force of the spring element (70).

11. Locking device (10, 70, 80) according to claim 10, characterized in that a first brake piston (48) and a second brake piston (50) are arranged on a piston rod (60), each of which brake pistons delimit a pressure chamber (52, 54), in that the second brake piston (50) faces the spring element (58) and the first brake piston (48) faces away from the spring element (58), and in that a partition wall (62) delimiting the pressure chamber (54) of the second piston (50) is provided between the brake pistons (48, 50).

12. Locking device (10, 70, 80) according to claim 10 or 11, characterized in that the partition wall (62) is supported on a housing stop (64) on the side facing away from the second brake piston (50).

13. Gripping or clamping apparatus (12) comprising a locking device (10, 70, 80) according to any of the preceding claims.

14. Gripping or clamping apparatus (12) according to claim 13, characterized in that two sliding jaws (14) that can be moved toward and away from one another are provided, the sliding jaws (14) each being motion-coupled to at least one working piston (16) delimiting a working pressure chamber, the working pistons (16) each providing a coupling portion (20) which is motion-coupled to a coupling member (22, 26) which is rotatably arranged about an axis of rotation (24), the coupling member (22) of the gripping or clamping apparatus (12) simultaneously forming or being rotationally coupled to the coupling member (26) of the locking device.