Clamping head arrangement

Abstract

The invention relates to a clamping head arrangement, in particular for clamping a drill string element, with several clamping jaw elements, each of which has a clamping surface designed in particular for clamping against a contact side of the drill string element, and a base body with guide rails along which the clamping jaw elements are slidably mounted, wherein the guide rails are angled to a central axis of the clamping head arrangement, so that a displacement of the clamping jaw elements along the guide rails causes an axial and a radial adjustment of the clamping jaw elements with respect to the central axis.According to the invention, the clamping jaw elements are each designed with a cylindrical or partially cylindrical guide body, and the guide tracks in the base body are designed as partially cylindrical guide channels in which a clamping jaw element with the cylindrical or partially cylindrical guide body is slidably mounted.

Description

[0001] The invention relates to a clamping head arrangement, in particular for clamping a drill string element, with several clamping jaw elements, each of which has a clamping surface designed in particular for clamping against a contact side of the drill string element, and a base body with guide rails along which the clamping jaw elements are slidably mounted, wherein the guide rails are angled to a central axis of the clamping head arrangement, so that a displacement of the clamping jaw elements along the guide rails causes an axial and a radial adjustment of the clamping jaw elements with respect to the central axis, according to the preamble of claim 1.

[0002] Such a clamping head arrangement is known, for example, from EP 4 339 417 A1. Another clamping head arrangement is described in US 7,775,270 B1. These clamping head arrangements serve to detachably clamp a cylindrical or tubular drill string element in order to transmit drilling torque from a rotary drill drive. At a distal end of a drill string, which is formed by one or more drill string elements, a drilling tool is attached during operation, through which, for example, soil material can be removed or displaced during pile drilling.

[0003] In these clamping head arrangements, the individual clamping jaw elements are mounted linearly displaceable along a base body in or on guide tracks. The guide tracks are designed concentrically to a central axis with a certain angle of inclination. This allows the clamping jaw elements to be adjusted radially during axial displacement in order to clamp or release the drill string element.

[0004] The clamping jaw elements must be movable along these guideways and simultaneously held in position so that they do not fall out of the guideway when the clamped drill string element is removed.

[0005] The guideways are typically designed with an undercut and can be manufactured as a dovetail guide, a T-guide, or a similar undercut guide. While these guideways ensure good guidance and reliable retention of the clamping jaw elements on the base body, they are susceptible to contamination and damage and are complex to manufacture. Undercut guideways, such as dovetail guideways, generally require special and therefore expensive form milling cutters for their production. Subsequently, hardening and finishing, such as complex grinding or honing, are necessary to achieve precise results on the guide surfaces. Specially designed grinding or honing tools must be used to suit the undercut guideways. This results in correspondingly high manufacturing costs for such a clamping head assembly.This also applies similarly to the manufacture of the associated clamping jaw elements, which must be designed to fit the undercut guideways.

[0006] The invention is based on the Task The basis is to specify a clamping head arrangement with a particularly simple and robust design.

[0007] The problem is solved according to the invention by a clamping head arrangement with the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims.

[0008] The clamping head arrangement according to the invention is characterized in that the clamping jaw elements are each designed with a cylindrical or partially cylindrical guide body and that the guide tracks in the base body are designed as partially cylindrical guide channels in which a clamping jaw element with the cylindrical or partially cylindrical guide body is slidably mounted.

[0009] A first aspect of the invention lies in moving away from the complex guideways with undercut, flat guide surfaces and instead forming the guideways in the base body as semi-cylindrical guide channels. Cylindrical channels can be created relatively easily using conventional drilling tools, which is relatively simple from a manufacturing perspective. Furthermore, after any hardening, a semi-cylindrical guide surface can be machined very precisely and efficiently using appropriately cylindrical grinding or reaming tools. A semi-cylindrical guide channel within the meaning of the invention is understood to be a cylindrical recess or bore that is open along an axial section, thus forming an open guide channel whose otherwise existing guide wall is symmetrical about a central or channel axis.The partially cylindrical channel or guide wall extends over an angular range of more than 180°, preferably between 240° and 300°, thus ensuring a certain degree of undercutting. The remaining angular range is open.

[0010] Another aspect of the invention is to design the clamping jaw elements with a cylindrical or semi-cylindrical guide body, corresponding to the semi-cylindrical guide channels. The guide body can form a kind of guide rail along the actual clamping jaw element, or preferably, the clamping jaw element itself can be made from a cylindrical base body with a clamping surface formed or attached to it. Thus, such a clamping jaw element with a cylindrical or semi-cylindrical guide body can also be manufactured relatively easily, for example, using a conventional lathe or turning machine.

[0011] The inner diameter of the guide channel and the outer diameter of the guide body of the clamping jaw element are designed to match each other and preferably form a very fine clearance fit, so that the respective clamping jaw element is guided exactly and reliably along the associated guide channel and is slidably mounted.

[0012] A preferred embodiment of the invention consists in the semi-cylindrical guide channels being open on the side facing the drill string element to be clamped. This ensures good and secure guidance of the clamping jaw elements in the guide channels, as well as stable and efficient transmission of even high clamping forces.

[0013] A particularly advantageous embodiment of the clamping head arrangement according to the invention can be achieved by designing the base body in an annular shape with a free interior space for receiving the drill string element and by having the guide channels open to the interior space. Such a clamping head arrangement with an annular base body can thus be designed to clamp a cylindrical drill string element on the outside. For this purpose, the free interior space in the annular base body has a larger diameter than the maximum diameter of a drill string element to be clamped.

[0014] The drill string element can be received in the interior and clamped by moving the clamping jaw elements along the guide tracks from a radially outer release position to a radially inner clamping position, in which the clamping jaw elements are pressed against the outside of the drill string element and thus the drill string element is held at least by friction.

[0015] Alternatively, for clamping a tubular drill string element on its inner side, the clamping head arrangement according to the invention can be further developed in that the base body is shaft- or block-shaped with an outer circumferential side in which the partially cylindrical guide channels with the clamping jaw elements are arranged, whereby a tubular drill string element can be clamped on its inner side. The outer diameter of the shaft- or block-shaped base body is smaller than the inner diameter of the tubular space of the drill string element to be clamped.

[0016] The shaft- or block-like base body can be inserted relatively into the tubular interior of the drill string element. By sliding the clamping jaw elements along the guide channels, they can be moved from a radially inner release position to a radially outer clamping position. In the clamping position, the clamping jaw elements can be pressed against the inside of the tubular drill string element. This allows the tubular drill string element to be clamped and held, at least by friction, on its inner surface, so that, for example, a torque can be transmitted to the tubular drill string element.

[0017] In a further embodiment of the clamping head arrangement, it is preferred that the clamping jaw elements are connected to at least one actuating element, which is adjustably mounted to move the clamping jaw elements relative to the base body. The actuating element can be, in particular, ring-shaped for an external chuck or disc- or block-shaped for an internal chuck. The actuating element is rigidly connected to the individual clamping jaw elements or preferably with a certain amount of play. By moving the actuating element, the individual clamping jaw elements are moved together along the guide tracks to perform a clamping or releasing movement.

[0018] In principle, the actuator can be adjusted in any suitable way using suitable means. According to a further development of the invention, it is particularly advantageous that the at least one actuator is axially displaceable by means of at least one actuating cylinder, in particular a hydraulic cylinder. Two or more actuating cylinders are particularly preferred, which are arranged as evenly as possible along the circumference of the actuator. The actuator can thus be adjusted or displaced relative to the base body, preferably in the axial direction. The actuating forces applied in this way are transmitted to the individual clamping jaw elements by the guide rails, which are angled to the central axis, in the manner of a wedge-type sliding mechanism, resulting in corresponding clamping or releasing forces.

[0019] According to a further development of the invention, it is preferred that each clamping jaw element is connected to the actuator via a connecting device with some play. The connecting device is particularly designed such that the clamping jaw elements can be axially displaced with the actuator. This provides a certain amount of play in a radial and / or axial direction, i.e., a certain degree of freedom of movement of the respective connected clamping jaw element relative to the actuator. Thus, by means of the respective connecting device, certain relative movements between the actuator and the respective clamping jaw element can be compensated for when the clamping jaw elements are adjusted.

[0020] A contact surface can be formed on the respective clamping jaw element at a contact member, which is mounted on the clamping jaw element with a certain amount of play. This allows minor misalignment errors to be compensated for and ensures secure, firm clamping.

[0021] According to a further development of the invention, it is particularly advantageous that a hook arrangement is formed on a rear region of each clamping jaw element to form the connecting device, which engages in a corresponding receiving holder on the actuator. The hook arrangement can be formed, in particular, by a groove-like recess in the preferably cylindrical clamping jaw element in a transverse direction. The receiving holder on the actuator can, in particular, be designed as a bracket or a corresponding recess in the actuator.

[0022] The hook assembly can be formed integrally with the clamping jaw element or by a separate hook element attached to the clamping jaw element. The receiving bracket can be designed as a single piece or as a separate part attached to the actuator. In principle, the connection device can be designed in any suitable manner, and conversely, the hook assembly can be on the actuator and the receiving bracket on the respective clamping jaw element.

[0023] According to one embodiment of the invention, it is particularly advantageous that the clamping jaw arrangement for forming a drilling drive assembly, especially on a drilling drive carriage, can be driven by at least one rotary drive. The clamping jaw arrangement can thus serve to transmit a drilling torque from one or more rotary drives to a drill string element. In particular, the drilling drive assembly can be used for drilling in earth or rock in civil engineering or mining, where relatively high torques need to be reliably transmitted to a drill string element.

[0024] The drill drive assembly formed by the chuck assembly can, in particular, be arranged on a drill drive slide with a slide body. The slide body has the chuck assembly with the at least one rotary drive on one side, while a linear guide device can be provided on the other side, with which the drill drive slide can be guided, for example, along a mast or a drill rig.

[0025] The invention further comprises a drilling rig for creating a borehole, particularly in soil, with at least one drill string element, wherein a chuck assembly according to the invention is provided. The drilling rig can, in particular, be designed with a chassis, especially a tracked chassis. The drilling rig can further comprise a mast or carriage, which preferably has a linear guide for guiding a drill drive carriage with the chuck assembly and at least one rotary drive. The mast or carriage can be slidably mounted.

[0026] The invention is further described below with reference to a preferred embodiment, which is shown schematically in the drawings. The drawings show: Fig. 1 a perspective view of an annular base body with a clamping jaw element for a clamping head arrangement according to the invention from the rear; Fig. 2 a perspective view of the annular base body with the clamping jaw element from Fig. 1 from the front; and Fig. 3 a perspective view of a clamping head arrangement according to the invention.

[0027] According to the Figure 1 and 2 A base body 12 for a clamping head arrangement 10 according to the invention can be annular with an interior 13 in which a cylindrical or tubular linkage element (not shown) can be received and clamped. Guide tracks 14 for receiving and guiding clamping jaw elements 20 are preferably formed along an inner annular surface of the base body 12 at uniform angular intervals. In the illustrated embodiment, three guide tracks 14 are provided by way of example.

[0028] In the Figure 1 and2 For clarity, only one clamping jaw element 20 is used in a guide track 14. According to the invention, the guide tracks 14 in the base body 12 are designed as partially cylindrical guide channels 15, i.e., with a cylindrical or partially cylindrical channel wall, wherein the respective guide channel 15 is open to the interior 13. The opening width W of the guide channel 15 is smaller than the cylinder diameter, which corresponds to the maximum channel width of the guide channel 15, forming an undercut in the guide channel 15.

[0029] Matching the design of the guide channels 15, the clamping jaw elements 20 are designed with a cylindrical or semi-cylindrical guide body 22 with a guide surface 24. The outer diameter of the guide body 22 forms a fit with the inner diameter of the associated guide channel 15, so that the respective clamping jaw element 20 is precisely slidably mounted in the guide channel 15.

[0030] The guide tracks 14 and the guide channels 15 each have a longitudinal or central guide axis, which is angled relative to a central axis of the annular base body 12. This angle ensures that axial displacement of the clamping jaw elements 20 in the guide channels 15 also results in a radial adjustment of the clamping jaw element 20 with respect to the central axis. Such radial adjustment allows, for example, a clamping surface 26 formed in the clamping jaw element 20 to be brought into contact with an outer surface of the drill string element to be clamped. In this way, a force-fit holding of the drill string element in the annular base body 12 is achieved.

[0031] To adjust or move the individual clamping jaw elements 20, these can have a hook arrangement 32 at their rear end, by means of which they can be connected to a Figure 1 and2 The hook arrangement 32 can be connected to the actuator not shown. It can be formed integrally on the clamping jaw element 20 by incorporating a groove-like recess 34, or it can be attached to the clamping jaw element 20 as a separate part.

[0032] According to Fig. 3 An exemplary clamping head arrangement 10 according to the invention with the annular base body 12 is shown. Figure 1 and 2The clamping jaw elements 20, which are slidably mounted in the annular base body 12, are held at their rear end region on an annular actuator 40 by means of the hook arrangement 32. For this purpose, bracket-like receiving holders 36 are attached to a front face of the annular actuator 40, forming a receiving window 37 into which the hook arrangement 32 engages. The hook arrangement 32 and the associated receiving holder 36 each form a connecting device 30 for the clamping jaw element 20 on the annular actuator 40.

[0033] The annular actuator 40 rotates at its rear side, which faces away from the clamping jaw elements 20, with respect to a drive flange 46, through which a torque can be transmitted from a rotary drive (not shown). Furthermore, the annular actuator 40 is axially displaceable via at least one actuating cylinder 50 relative to a central or bore axis of the clamping head assembly 10 (not shown).

[0034] The annular base body 12 has a closing ring 18 on its front side, which surrounds the interior 13 in an annular manner. On its rear side, opposite the closing ring, the annular base body 12 is rigidly connected to the drive flange 46 via a connecting sleeve 19 for the transmission of torque, in particular a relatively high drilling torque. The annular actuator 40 is slidably arranged on the outside of the connecting sleeve 19.

[0035] By axially displacing the annular actuating element 40 by means of the at least one actuating cylinder 50, the individual clamping jaw elements 20 are moved into the respective connecting devices 30. Fig. 3 The partially cylindrical guide channels 15 (not shown in detail) are displaced. Due to the angling of the guide channel axes to the central axis of the clamping head arrangement 10, the individual clamping jaw elements 20 are also radially adjusted.

[0036] By extending the at least one actuating cylinder 50, which can in particular be a hydraulic cylinder, the actuating element 40, together with the clamping jaw elements 20, can be moved axially downwards towards the end ring 18, whereby the individual clamping jaw elements 20 slide radially inwards towards the interior 13 and can radially clamp and forcefully hold a drill string element arranged there. In this way, the drilling torque from the drive flange 46 can be transmitted to such a clamped drill string element.

[0037] By retracting at least one actuating cylinder 50, the annular actuating element 40 can be moved back accordingly, whereby the clamping jaw elements 20 are retracted axially and also returned radially outwards to their initial position. In this reset position, a linkage element can be removed from the clamping head assembly 10 and a new element can be inserted.

Claims

1. Clamping head assembly, in particular for clamping a drill string element, comprising: - several clamping jaw elements (20), each having a clamping surface (26) designed in particular for clamping against a contact side of the drill string element, and - a base body (12) with guide tracks (14) along which the clamping jaw elements (20) are slidably mounted, wherein the guide tracks (14) are angled to a central axis of the clamping head assembly (10), so that a displacement of the clamping jaw elements (20) along the guide tracks (14) causes an axial and a radial adjustment of the clamping jaw elements (20) with respect to the central axis. characterized by - that the clamping jaw elements (20) are each designed with a cylindrical or partially cylindrical guide body (22) and - thatthe guideways (14) in the base body (12) are designed as semi-cylindrical guide channels (15) in which a clamping jaw element (20) with the cylindrical or semi-cylindrical guide body (22) is slidably mounted.

2. Clamping head arrangement according to claim 1, characterized by that the semi-cylindrical guide channels (15) are open on the side, which are directed towards the drill string element to be tensioned.

3. Clamping head arrangement according to claim 1 or 2, characterized by that the base body (12) is designed in a ring shape with a free interior space (13) for receiving the drill string element and that the guide channels (15) to the interior (13) are open.

4. Clamping head arrangement according to claim 1 or 2, characterized by thatthe base body (12) is designed in a shaft- or block-like manner with an outer circumferential side in which the semi-cylindrical guide channels (15) with the clamping jaw elements (20) are arranged, wherein a tubular drill string element can be clamped on an inner side.

5. Clamping head arrangement according to one of claims 1 to 4, characterized by that the clamping jaw elements (20) are connected to at least one actuating element (40) which is slidably mounted to move the clamping jaw elements (20) relative to the base body (12).

6. Clamping head arrangement according to claim 5, characterized by that that at least one actuator (40) is axially displaceable by means of at least one actuating cylinder (50), in particular a hydraulic cylinder.

7. Clamping head arrangement according to claim 5 or 6, characterized by that Each clamping jaw element (20) is connected to the actuator (40) via a connecting device (30) with a clearance.

8. Clamping head arrangement according to claim 7, characterized by that To form the connecting device (30) on a rear area of ​​each clamping jaw element (20) a hook arrangement (32) is formed which engages in an associated receiving holder on the actuator (40).

9. Clamping head arrangement according to one of claims 1 to 8, characterized by that this is capable of being driven by at least one rotary drive to form a drilling drive arrangement, in particular to a drilling drive slide.

10. Drilling device for creating a borehole, in particular in soil, with at least one drill string element, characterized by that a clamping head arrangement (10) according to one of claims 1 to 9 is given.

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