Clamping device for positioning and clamping workpieces in internal contours, especially bores

Abstract

Clamping device for positioning and clamping workpieces in internal contours, in particular bores of workpieces, in which a clamping sleeve engages in a workpiece bore and can be expanded by a drawbar, characterized in that - that the clamping device consists of a vertically movable clamping arm (2) which performs a positioning and clamping movement radially and a vertically fixed clamping sleeve (1), - that the clamping sleeve (1) is radially movable for positioning and / or clamping, - that the clamping sleeve (1), which is open on one side along its longitudinal side and guides the clamping arm (2), has a longitudinally formed recess with an inwardly directed inclined contact surface (6) which widens upwards from the vertical, - that the receptacle (10) of the clamping sleeve (1) has a conically extending or hemispherical support (7) and - that the clamping arm (2) has at its upper end a clamping head (8) which, when the piston (4) arranged at the lower end of the clamping arm (2) is pulled down, performs a movement projecting out of the plane of the clamping sleeve (1) and exerts the clamping function against the inner contour of the bore of the workpiece (5) and - that when the piston (4) is reset, the tension arm (2) is reset via a spring element (11).

Description

[0001] The invention relates to a clamping device according to the preambles of claims 1 and 2.

[0002] For machining, assembly, handling, or inspection, workpieces or assemblies must be positioned precisely and aligned with corresponding features on clamping bodies, fixed, clamped, or supported. Internal contours such as bores are also commonly used for this purpose.

[0003] Suitable clamping devices and clamping methods are described, for example, in DE4020981, JP2012-101345, JP2011 011288, JP2013-056418, DE102005013112, and DE102014019712. A common feature of these known solutions is a central conical or pyramidal tension element that spreads radial clamping segments. A disadvantage is the technically inherent limitation that such a system can only be implemented practically with certain minimum bore diameters. A further disadvantage is that the described systems either cannot perform radial positioning functions or are only capable of positioning.

[0004] Another alternative solution is shown in EP2676766A1. In this solution, the clamping device consists of a strut projecting upwards from the main body of a housing, a vertically and radially movable positioning rod inserted into the upper section of the housing, and, together with the strut, a cam section inserted into the circular bore of the workpiece to be positioned. The clamping device also includes a cam surface arranged vertically at the upper right end of the positioning rod. Opposite this, on the left side, is a pressure section. A ball is positioned between this inner cam surface and the positioning rod. When the positioning rod is pushed upwards by a drive mechanism to lock it in place, the cam section with the ball pushes the cam surface to the left and presses against the inner surface of the circular hole in the workpiece.From an assembly perspective, this solution is quite complicated and elaborate, and adapting it to different workpiece bore diameters is difficult. Clamping a workpiece across multiple bores of the same workpiece is challenging due to the lack of tolerance compensation between the bores.

[0005] DE 102004006213B3 is a low-profile quick-clamping device for clamping workpieces to be machined, in which a clamping sleeve engages in a bore of the workpiece, wherein the clamping sleeve with inclined inner surfaces is designed as a narrow slotted ring and this can be expanded via a sleeve-shaped conical element with a drawbar, wherein the drawbar is hat-shaped at the upper end.

[0006] The narrow slotted ring serves as a clamping element, which also means that its expansion mode is limited in terms of force absorption and therefore the clamping force cannot be optimally adjusted.

[0007] Furthermore, a clamping device for clamping a workpiece is known from CH 705 531 B1, wherein the clamping device is designed in at least two parts and comprises a clamping element having a profile, and the lifting element connected to the clamping element for clamping by axial relative movement between the profile of the clamping element and the counter-profiling. The lifting element can be made of a particularly tough material, while the material of the clamping element is selected with regard to high wear resistance.

[0008] From FR 2 781 400 A1, a centering and clamping device, particularly for motor vehicle body parts, is known, comprising an actuating device arranged in a housing, with which, in combination, at least one retractable clamping element and a centering element in which the at least one clamping element is retractably arranged can be actuated. Each clamping element has an end region in the form of a claw extending radially outwards and downwards.

[0009] The object of the invention is to overcome the disadvantages of the prior art and to create a method for positioning and / or radially compensating clamping of workpieces in internal contours, in particular small-diameter bores, which allows for adjusting the clamping force to the required degree and compensating for dimensional tolerances of the bores in which the clamping device is to engage. The solution should have a robust and contamination-resistant design and allow for combined use as a positioning or compensating clamping system.

[0010] This problem is solved with a clamping device having the features according to claim 1 or claim 2.

[0011] Functionally, the technical implementation is achieved by means of a combination of a vertically movable clamping arm, which thus acts as a pull rod, and a vertically fixed clamping sleeve, which is arranged in a bore of a workpiece lying on a support in order to position and / or clamp the workpiece.

[0012] The clamping sleeve has a longitudinally formed recess with an inclined contact surface, which widens upwards from the vertical.

[0013] By moving the clamping arm, positioned in the recess of the clamping sleeve, downwards, it slides along the angled contact surface of the clamping sleeve, is guided radially out of the radial plane of the clamping sleeve, and its head is moved against the inner contour of the workpiece bore, thereby pressing the workpiece radially against the outer surface of the clamping sleeve. The clamping sleeve has clamping surfaces which, due to their shape, amplify the holding force and securely guide the inner contour of the workpiece bore. The force is generated directly and via a short path between the workpiece contour and the clamping arm or clamping sleeve, solely by the application of a downward tensile force by the tensioning element, for example, via a piston. Reversing the movement returns the clamping arm to its original position and releases the workpiece.

[0014] To support force build-up, the clamping arm can have a clamping head at its upper end.

[0015] By designing the clamping sleeve either as a radially movable or as a radially fixed element, the clamping device can be designed for positioning and clamping or simply for radially compensating clamping.

[0016] This robust and uncomplicated design of the clamping device with only one clamping arm also allows the clamping device to be dimensioned for use in smaller workpiece bores than with the elements described in the prior art.

[0017] Compared to multi-segmented clamping sleeves, this solution results in a comparatively robust and less sensitive design due to contamination.

[0018] Different dimensions of the supports, clamping sleeve and clamping arm allow for easy adaptation to different workpiece geometries.

[0019] To compensate for dimensional tolerances of the bore diameters, the clamping sleeve does not have a flat support at the lower end, but rather a hemispherical or conical support, so that it can deflect radially in the case of radial movement via this curvature.

[0020] The pulling movement is achieved via a pulling element, e.g. a piston, located below the clamping arm.

[0021] The initiation of the pulling motion can be done via a suitable fluid cylinder, manually mechanically or electrically. List of characters

[0022] The attached drawings show: Fig. 1. A perspective view of a variant of the clamping device Fig. 2 a perpendicular cut through the in Fig. 1. Variant of a clamping device shown in loading and unloading position with radially movable clamping sleeve Fig. 3 a perpendicular cut through the in Fig. 1. Variant of a clamping device shown in clamping position with radially movable clamping sleeve Fig. 4 a perpendicular cut through the in Fig. 1. Variant of a clamping device shown in clamping position with radially fixed, immovable clamping sleeve and Fig. 5 a top view of the support of the clamping device Example implementation:

[0023] According to the figures Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. Figure 5 shows a clamping device according to the invention, in which a clamping sleeve 1 is located within the bore of a workpiece 5 and a clamping arm 2, inserted into the clamping sleeve 1, is driven vertically downwards by means of an integrated cylinder so that it is guided against a contact surface 6 of the clamping sleeve 1. The inclined contact surface 6, which increases centrally towards the top, creates a clamping movement at the upper end of the clamping arm 2 directed radially towards the inner wall contour of the workpiece 5. This radial clamping movement is generated by a sliding movement of the clamping arm 2 along the contact surface 6 of the clamping sleeve 1 by the linear pulling movement of the piston 4. Simultaneously, this creates a downward pull component that presses the workpiece 5 onto the support 3.

[0024] As an alternative to a directly connected piston, a laterally deflected force transmission via a wedge gear or a lever is also possible. The function of the in Fig. The fluid cylinder with piston 4 shown in Figure 2 can also be operated by a manual mechanical or electromechanical drive.

[0025] Due to the radial mobility of the clamping sleeve 1 in the support 3 and the hemispherical support 7 of the clamping sleeve 1, the clamping arm 2 and clamping sleeve 1 can adapt to the actual position of the bore of the workpiece 5 within a permissible tolerance.

[0026] The coupling between clamping arm 2 and piston 4 is also designed to compensate, in that the support 7 of the receptacle 10 of the clamping sleeve 1 is hemispherical.

[0027] Is there a radial movement of the clamping sleeve 1 within the support 3, as in Fig. As shown in 4, if prevented, the clamping device can perform a positioning function radially to its main axis.

[0028] In Fig. Figure 5 shows how clamping arm 2 pushes the workpiece 5 against two clamping surfaces 9 on the clamping sleeve 1. Depending on the design and number of these clamping surfaces 9, this radial positioning function with at least 2 clamping surfaces can be used as positioning along a diameter (as in Figure 5). Fig. 4) or with only one clamping surface along one axis. Reference symbol list 1 clamping sleeve with radial mobility 2 clamping arms 3rd edition for workpiece 5 4 pistons 5 workpieces 6 Contact surface inside the clamping sleeve 1 7 Hemispherical support of the receptacle 10 of the clamping sleeve 1 8 Clamping head of the clamping arm 2 9 Clamping surface on the outer contour of the clamping sleeve 1 10 Intake 10 of the clamping sleeve 11 Spring element 12 Tension sleeve without radial mobility.

Claims

Clamping device for positioning and clamping workpieces in internal contours, in particular bores of workpieces, in which a clamping sleeve engages in a workpiece bore and can be expanded by a drawbar, characterized in that: - the clamping device consists of a vertically movable clamping arm (2) that performs a positioning and clamping movement radially and a vertically fixed clamping sleeve (1); - the clamping sleeve (1) is radially movable for positioning and / or clamping; - the clamping sleeve (1), which is open on one side longitudinally and guides the clamping arm (2), has a longitudinally formed recess with an inwardly directed inclined contact surface (6) which widens upwards from the vertical.- that the receptacle (10) of the clamping sleeve (1) has a conically extending or hemispherical support (7) and - that the clamping arm (2) has at its upper end a clamping head (8) which, when the piston (4) located at the lower end of the clamping arm (2) is pulled downwards, performs a movement projecting out of the plane of the clamping sleeve (1) and exerts the clamping function against the inner contour of the bore of the workpiece (5) and - that when the piston (4) is returned to its original position, the clamping arm (2) is returned to its original position by means of a spring element (11). Clamping device for positioning and clamping workpieces in internal contours, in particular bores of workpieces, in which a clamping sleeve engages in a workpiece bore and can be expanded by a drawbar, characterized in that: - the clamping device consists of a vertically movable clamping arm (2) that performs a clamping movement and a vertically fixed clamping sleeve (12); - the clamping sleeve (12) is radially fixed for positioning and clamping and the workpiece is pulled against the clamping sleeve (12) by the clamping arm (2); - the clamping sleeve (12), which is open on one side along its longitudinal side and guides the clamping arm (2), has a longitudinally formed recess with an inwardly directed inclined contact surface (6) that widens upwards from the vertical; - the receptacle (10) of the clamping sleeve (12) has a flat support (7).- that the clamping arm (2) has at its upper end a clamping head (8) which, when the piston (4) located at the lower end of the clamping arm (2) is pulled downwards, performs a movement projecting out of the plane of the clamping sleeve (1) and exerts the clamping function against the inner contour of the bore of the workpiece (5) and - that when the piston (4) is returned to its original position via the spring element (11), the clamping arm (2) is returned to its original position and the workpiece is released from clamping. Clamping device according to claim 1 or 2, characterized in that the clamping sleeve (1, 12) has at least one clamping surface (9) on its outer contour and the clamping sleeve (1) performs a radially pivoting or radially linear sliding movement against the inner bore contour of the workpiece (5) via the clamping surface (9) by means of the clamping arm (2) moving along the inclined contact surface (6). Clamping device according to claim 1 or 2, characterized in that the outer cylindrical surfaces of clamping sleeve (1, 12) and clamping arm (2) have a cylindrical contour or a contour with protrusions.

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