TOOL FOR ROUGHENING A BOREHOLE SURFACE

Abstract

A tool for roughening a borehole surface. The tool includes a coupling portion for clamping the tool in a drilling machine; and a tool head for machining the borehole surface, where the tool head has an outer shell surface on which a cutter protrudes laterally from the shell surface, and where the outer shell surface has a camber along the longitudinal direction of the tool.

Claims

1: A tool for roughening a borehole surface, comprising: a coupling portion for clamping the tool in a drilling machine; and a tool head for machining the borehole surface, wherein the tool head has an outer shell surface on which a cutter protrudes laterally from the shell surface, and wherein the outer shell surface has a camber along the longitudinal direction of the tool.

2: The tool according to claim 1, wherein the outer shell surface has a maximum diameter, which is disposed centrally with respect to the longitudinal extent of the tool head.

3: The tool according to claim 1, wherein the cutter comprises pins of a cutting material, and wherein the pins are distributed circumferentially with an angular spacing.

4: The tool according to claim 3, wherein the pins are disposed with an angular spacing with respect to the longitudinal axis of the tool, and wherein the angular spacing is 30 to 180.

5: The tool according to claim 1, wherein the maximum diameter of the tool head is smaller than the nominal diameter of a borehole to be machined.

6: The tool according to claim 1, wherein the coupling portion is disposed at a first end of a tool shank and the tool head at an opposite, second end of the tool shank, and wherein the tool shank has a diameter smaller than that of the tool head.

7: The tool according to claim 6, wherein the tool shank is at least as long as the tool head in axial direction.

8: The tool according to claim 1, wherein the axial length of the tool head corresponds to at least nine times the maximum diameter of the tool head.

9: The tool according to claim 1, wherein the axial length of the tool head corresponds to at least nine times the nominal diameter of a borehole to be machined.

10: The tool according to claim 1, the largest diameter of the tool head is at least 30% larger than the diameter of a tool shank joining a tool head and coupling portion.

11: The tool according to claim 3, wherein the pins are disposed with an angular spacing with respect to the longitudinal axis of the tool, and wherein the angular spacing is 60 to 150.

12: The tool according to claim 1, wherein the cutter comprises carbide or diamond pins, wherein the pins are distributed circumferentially with an angular spacing.

Description

[0018] The invention will be described in more detail hereinafter on the basis of a drawing that schematically illustrates exemplary examples, wherein:

[0019] FIG. 1 shows a first configuration of an inventive tool in a perspective view, a front view and a side view; and

[0020] FIG. 2 shows a second configuration of an inventive tool in a perspective view, a front view and two side views.

[0021] FIG. 1 shows a tool 10 for roughening a borehole surface (not illustrated) in a perspective view, a front view and a side view. Tool 10 has a coupling portion 12 for clamping tool 10 in a drilling machine (not illustrated) and a tool head 14 for machining a borehole surface. Tool head 14 has an outer shell surface 16. Cutting means 18, which project radially relative to shell surface 16, are disposed on outer shell surface 16. Outer shell surface 16 has a camber along the longitudinal direction a of the tool, as is apparent in side view.

[0022] Shell surface 16 has a maximum diameter D1, which is disposed centrally with respect to the longitudinal extent of tool head 14. Starting from maximum diameter D1, shell surface 16 tapers in the direction of a front end 20 and an opposite end 22 at the shank, respectively to a minimum diameter D2 smaller than diameter D1. In other words, the outer shell surface in side view is bowed outward in a radial direction r.

[0023] The cutting means provided on shell surface 16 comprise carbide pins 18, which are distributed circumferentially with an angular spacing of 120 and also axially along longitudinal axis A of the tool.

[0024] The axial longitudinal extent of tool head 14 is larger than nine times the maximum diameter D3 of the tool head. Maximum diameter D3 of tool head 14 is determined by the diameter of the envelope circle of those carbide pins 18 that are disposed in the region of maximum diameter D1 of the shell surface.

[0025] According to alternative configurations of the invention, the axial longitudinal extent of the tool head is larger than nine times the nominal diameter of the borehole to be machined.

[0026] Coupling portion 12 is disposed at a first end of a tool shank 24 and tool head 14 at an opposite, second end of tool shank 24. Tool shank 24 has a diameter smaller than that of tool head 14. The axial length of tool shank 24 corresponds substantially to the axial length of tool head 14.

[0027] For roughening of a borehole surface (not illustrated), the inventive tool 10 is clamped in a drilling machine (not illustrated). Tool 10 is introduced together with the tool head into a borehole (not illustrated). In this connection, the nominal diameter of the borehole is preferably larger than the maximum diameter D3 of tool head 14. The drilling machine executes rotation of tool 10, while a swiveling or stirring motion is superposed on this rotation by the user. Cambered tool head 14 is guided by the user along the borehole surface, so that the guidance of tool 10 is predetermined by the shape of tool head 14. In this way, uniform roughening of the borehole surface can be achieved. In addition, due to the circumferential distribution of carbide pins 18, the wear of tool 10 in the region of outer shell surface 16 is reduced, especially at the height of maximum diameter D1.

[0028] FIG. 2 shows a further configuration of a tool 10, wherein this alternative configuration is characterized by a changed shape of coupling portion 12, which has a diameter larger than the shank diameter.

[0029] The tool is constructed such that the tool head has a largest diameter that is at least 30% larger than the diameter of the tool shank.