CUTTING TOOL HAVING A DEPTH STOP

Abstract

A cutting tool having a shank and a cutting head, wherein the shank carries a depth stop, which limits penetration depth into a workpiece, via at least one pivot bearing, and the depth stop is spring-preloaded away from the cutting head, via the at least one pivot bearing, against a shank-side stop.

Claims

1. A cutting tool having a shank and a cutting head, wherein the shank carries a depth stop, which limits penetration depth into a workpiece, via at least one pivot bearing, and the depth stop is spring-preloaded away from the cutting head, via the at least one pivot bearing, against a shank-side stop.

2. The cutting tool according to claim 1, wherein the at least one pivot bearing is axially displaceable, and the shank-side stop is formed from an axially adjustable setting stop.

3. The cutting tool according to claim 1, wherein a compression spring is arranged between the cutting head and the at least one pivot bearing.

4. The cutting tool according to claim 3, wherein the compression spring is supported on the cutting head.

5. The cutting tool according to claim 3, wherein the compression spring is formed from a disk spring unit.

6. The cutting tool according to claim 2, wherein the setting stop is formed from a bushing, which is arranged on the shank so that the position can be set.

7. The cutting tool according to claim 1, wherein the depth stop is formed at a sleeve body, which receives the at least one pivot bearing.

8. The cutting tool according to claim 7, wherein the at least one pivot bearing is axially supported on an annular projection of the sleeve body projecting radially inward.

9. The cutting tool according to claim 8, wherein two pivot bearings are arranged on both sides of the annular projection.

10. The cutting tool according to claim 1, wherein the at least one pivot bearing is formed from a rolling bearing.

11. The cutting tool according to claim 1, wherein the at least one pivot bearing and the shank-side stop sit directly on the shank.

Description

[0020] A preferred embodiment of a cutting tool according to the invention will be described below on the basis of a schematic drawing.

[0021] The sole FIGURE shows a countersinking tool, which carries a depth stop, as example for a cutting tool according to the invention.

[0022] The countersinking tool 1 shown in the FIGURE has a shank 2 and a cutting head 3 connected to the shank 2. Reference numeral 4 specifies the axis of rotation. In the shown embodiment, the cutting head 3 is formed with multiple blades and has a guide pin 5. In the shown embodiment, the cutting head 3 is connected in a non-releasable manner to the shank 2, in particular to a cylinder portion 6 of the shank 2. In addition to the already mentioned cylinder portion 6, which carries the cutting head 3, the shank 2, which is embodied in several pieces in the shown embodiment, has a threaded portion 7, which connects to the cylinder portion 6. In the shown embodiment, the threaded portion 7 is connected in a non-releasable manner to the cylinder portion 6. In the shown embodiment, the cutting head 3 and the shank 2, in particular the cylinder portion 6 and the threaded portion 7, are in particular made from one piece. The threaded portion 7 is screw-connected to a coupling piece 8 for connecting the countersinking tool 1 to a (non-illustrated) tool holder or the like. As is shown in the FIGURE, the threaded portion 7 is screwed into a threaded bore 9 of the coupling piece 8 for this purpose.

[0023] The cylinder portion 6 of the shank 2 carries a depth stop 12, which limits the countersinking depth, via two rolling bearings 10, 11, which are formed by ball bearings in the shown embodiment. The inner bearing rings 10a, 11a of the two rolling bearings 10, 11 are in each case arranged in an axially displaceable manner on the cylinder portion 6 with a defined clearance adaptation. The outer bearing rings 10b, 11b of the two rolling bearings 10, 11 are received at an axial distance from one another with a defined press fit in a sleeve body 13 of the depth stop 12, which engages around the cutting head 3. For this purpose, the sleeve body 13 has a annular projection 14, which projects radially to the inside. On both sides of the annular projection 14, the two rolling bearings 10, 11 are supported on said annular projection, as it is shown in the FIGURE. The axial length of the annular projection 14 thus determines the axial distance of the two rolling bearings 10, 11.

[0024] A compression spring 15 arranged between the cutting head 3 and the rolling bearing 10 close to the cutting head creates a spring-preloading, by means of which the depth stop 12 is preloaded, via the two rolling bearings 10, 11, away from the cutting head 3 against a setting stop 16, which is screwed onto the threaded portion 7. As it is shown in the FIGURE, the compression spring 15 formed from a disk spring unit is clamped in particular between the rear side of the cutting head 3 and the inner bearing ring 10a of the rolling bearing 10 close to the cutting head. The inner bearing ring 11a of the rolling bearing 11 close to the cutting head furthermore abuts on the one setting stop 16, which is screwed onto the threaded portion 7 of the shank 2. In the shown embodiment, the setting stop 16 is formed from a knurled nut, which is screwed onto the threaded portion 7. After the position has been set, the setting stop 16 can be fixed by means of a clamping screw 17, which pushes against the threaded portion 7 and which is screwed into a radially oriented threaded bore 18 of the setting stop 16.

[0025] In the state shown in the FIGURE, the spring force of the compression spring 15 is introduced into the inner bearing ring 10a of the rolling bearing 10 close to the cutting head and is transferred to the setting stop 16 via the inner bearing ring 11a of the bearing ring 11 distant from the cutting head, which abuts on the setting stop 16.

[0026] A reduction of an axial bearing clearance in the two rolling bearings 10, 11 and an axial assembly clearance between the sleeve body 13 and the two rolling bearings 10, 11 is attained by means of the spring-preloading, as a result of which a clearance-free and precise positioning and position setting of the depth stop 12 in the axial direction is made possible.

[0027] In the shown embodiment, the depth stop 12 is positioned as follows. Due to the grinding of the clearance surfaces, the blades, which are not shown in more detail, on the cutting head 3 usually have a cutting height difference (which is not shown in the FIGURE). For the axial position setting of the depth stop 12, a highest blade in the tool feed direction is now assumed, which first cuts or enters, respectively, into a workpiece during a machining by means of countersinking and thus creates the largest countersinking depth or the largest countersinking diameter, respectively. The radius point, which corresponds to a predefined target diameter for the counterbore, is determined for this highest blade. A zero line 17, which is suggested in a dashed manner in the FIGURE, to which the depth stop 12 is to be set, then lies axially at the height of this radius point. For this purpose, the rolling bearings 10, 11, which carry the depth stop 12, are adjusted against or at the spring-preloading, respectively, in the direction of the cutting head 3 until the depth stop 12 comes to rest on the above-mentioned zero line 17. Due to the spring-preloading, an axial bearing clearance and/or assembly clearance is minimized when setting the depth stop 12. The depth stop 12 can thus be set precisely to the zero line 17, which determines the predetermined target diameter for the countersink for the highest blade.

[0028] It goes without saying that the feature combinations resulting for the person of skill in the art from the claims as well as from the acknowledgement of the claims result in various modifications for the embodiment shown in the FIGURE.

[0029] For instance, the cutting tool according to the invention is not limited to a countersinking tool. It can also be a drilling or milling tool, for example, the respectively available cutting head can be formed with one or multiple blades.

[0030] Deviating from the shown embodiment, in which the cutting head is made from one piece with the shank, the cutting head and the shank can be made separately, e.g. of different materials (for example the cutting head of a harder material and the cutting head of a softer material), and can then be connected to one another in a non-releasable manner by means of a substance-to-substance bond, e.g. by means of soldering. As an alternative to the non-releasable connection of the cutting head with the shank, the cutting head can also be connected in a releasable manner, i.e. in an exchangeable manner, to the shank by means of a positive and/or non-positive connection. In addition to the exchangeability, this alternative also provides the opportunity of producing and of combining the cutting head and the shank from different materials.

[0031] The shank can furthermore be formed cylindrically throughout. The shank-side stop could be formed in this case by a bushing, which can be axially displaced on the cylindrical shank and which can be axially fixed to the shank by means of a clamping screw. In particular in this case, the cylindrical shank can be clamped directly into a tool holder (chuck) or the like without interconnecting the coupling piece provided in the above embodiment.

[0032] At least one pivot bearing, which carries the depth stop, is usually sufficient for the rotationally movable bearing of the depth step. As in the shown embodiment, the pivot bearing can be formed from a rolling bearing, in particular ball bearing. This is not absolutely necessary, however. Instead of a rolling bearing, a sliding bearing as well as a combination of different bearing types could also be used.

[0033] Advantageously, the depth stop can be axially adjusted, as in the shown embodiment. This is also not absolutely necessary, however. The depth stop can be secured, for example, to the shaft in an axially unchangeable manner.

[0034] A spring-preloading exerted on the depth stop can be created via a compression spring arranged between the cutting head and the depth stop, as in the shown embodiment. Instead of a compression spring, it would generally be possible to use a tension spring, which pulls the depth stop axially away from the cutting head against a shank-side stop.

[0035] Instead of a disk spring unit, a coil spring or coil spring assembly, respectively, can generally also be used to create the spring-preloading.

[0036] Deviating from the shown embodiment, in which the two rolling bearings and the shank-side sit directly on the shank, the rolling bearings and the shank-side stop could also be arranged on the shank, for example, via a bushing fixed to the shank, i.e., indirectly, following the example of DE1020141157687 B3.