Countersinking tool

Abstract

The aim of the invention is to improve the smooth running and reduce the tendency to chatter in countersinking tools, comprising a connection point for introducing a torque with respect to a rotational or drive axis by means of a drive device and comprising a cutting assembly with four cutting edges which are uniformly slanted by a polar angle of 45°±0.5° with respect to the rotational or drive axis. This is achieved in that the four cutting edges (4, 5, 6, 7) are to be arranged in pairs so as to be rotationally offset relative to one another by four different partial angles with respect to the rotational or drive axis, wherein the four partial angles increase in order over the circular arc, and the smallest partial angle between two cutting edges (4, 5) lies in an angular range of 74° to 76°

Description

[0001] Hau2U-01-2024-36S03701 -HauPtPmst -0008 PCT / DE2024 / 000006 RUKO GmbH Precision Tools January 23, 2024 RW220052WOP Countersinking tool Technical field The present disclosure relates to improvements in tools and in particular to countersinking tools used for the machining of a conical or partially conically enlarged or expanded section in a hole. Countersinking tools are used for the machining of sections in bores. This can particularly relate to the conical expansion of the opening of a bore towards the material surface. Countersinking tools for a single conical expansion are common and are referred to as countersinks in the present illustration. Conical expansions of bore exits are sometimes desired in order to be able to mount screw or rivet heads in a recessed manner.Taper angles of 60°, 90° and 120° are typical in such applications. Other values ​​can of course be selected for special applications. Countersinking tools typically have more than two cutting edges distributed around the circumference. Having more than two cutting edges facilitates self-centering, i.e. aligning the countersinking tool with the axis of the existing hole due to the axial feed force. The tendency of a countersinking tool to self-center can improve results when working by hand. Countersinks for most metal materials have three or four cutting edges, which can be evenly or unevenly distributed around the circumferential angle. A countersink with three unevenly distributed cutting edges is known from the document EP 3 071 355 A1. There the advantage of the... Hau25-01-2024-3SS03701 -HauPtPost -0010 PCT / DE2024 / 000006 RUKO GmbH Präzisionswerkzeuge 23.01.2024 RW220052WOP increased running smoothness is specified by the uneven distribution of the cutting edges. A countersink with four unevenly distributed cutting edges is known from US Pat. No. 2,795,979. There, increased running smoothness and a reduced tendency to form chatter marks are cited as advantages of the uneven distribution of the cutting edges. Against this background, a need can be seen to further improve an asymmetrically divided countersinking tool with four cutting edges. Concepts The technical concept of the claim can fundamentally address the need explained above. Embodiments and alternatives are specified in the dependent claims.A countersinking tool according to the concept has a connection point for introducing a torque with respect to a rotation or drive axis by a drive device and further has a cutting edge arrangement with four cutting edges which are uniformly angled at a polar angle of 45° with respect to the rotation or drive axis. ° ±0.5. Furthermore, the four cutting edges are arranged in pairs, offset from each other by four different pitch angles relative to the rotational or drive axis. The four pitch angles increase in sequence across the circular arc, with the smallest pitch angle between two cutting edges lying in the angle range between 74 and 76. The special selection of the pitch angles results in a self-centering of the countersinking tool at a taper angle of 90° that exceeds the state of the art. Hau25-01-2024-38S03701 —HauPtPost -0011 PCT / DE2024 / 000006 RUKO GmbH Präzisionswerkzeuge 23.01.2024 RW220052WOP The smooth running is improved. Finally, a significant reduction in chatter tendency can be observed. In addition, the countersinking tool according to the concept can be designed such that the partial angle following the first partial angle lies in the angular range between 84 and 86. The countersinking tool according to the concept can be designed cumulatively or alternatively such that two consecutive partial angles add up to 180. The countersinking tool according to the concept can be designed cumulatively or alternatively such that the third partial angle following the second partial angle lies in the angular range between 102 and 106. The countersinking tool according to the concept can be designed cumulatively or alternatively in such a way that the four cutting edges lie on a common cone or truncated cone whose central axis coincides with the axis (A).The countersinking tool according to the concept can be further configured, either cumulatively or alternatively, such that the connection point is a cylindrical, round-flattened, polygonal, hexagonal, or otherwise prismatically shaped clamping pin. The countersinking tool according to the concept can be further configured, either cumulatively or alternatively, such that the polar angle () is between 44 and 45. The countersinking tool according to the concept can be further configured, either cumulatively or alternatively, such that the cutting edge arrangement is formed integrally with the connection point. The countersinking tool according to the concept can be further configured, either cumulatively or alternatively, such that the. Hau25-01-2024-38503701-HauPtPost -0012 PCT / DE2024 / 000006 RUKO GmbH Präzisionswerkzeuge 23.01.2024 RW220052WOP Cutting edge arrangement comprises four substantially equally wide and equally shaped chip flutes. Brief description of the figures An exemplary embodiment of an asymmetrically divided countersinking tool with four cutting edges in implementation of one or more of the concepts outlined above is explained in the following section with reference to the attached drawing. Therein shows: Fig. an exemplary countersinking tool in a side view; and Fig. the exemplary countersinking tool according to Fig. in a front view. Exemplary embodiments According to Fig. an exemplary countersinking tool comprises a connection point for a drive device. This connection point is configured to introduce a torque onto the countersinking tool with respect to a rotational or drive axis A.The torque can be provided in a manner known per se by the rotating spindle of a manually or motor-operated drilling machine. As shown in Fig. , the connection point can be designed as a prismatic pin. In particular, it can be a substantially cylindrical shaft. Very particularly, the substantially cylindrical shaft can have a plurality of flats in order to improve the transmission of torque from a three-jaw drill chuck. Furthermore, the exemplary countersinking tool according to Fig. 1 comprises a cutting edge arrangement 3 which comprises four cutting edges 4 and 5. The exemplary countersinking tool is configured as a countersink. Accordingly, the four cutting edges 4 and 5 are inclined by a polar angle P to the rotational axis. Hau25-01-2024-38S03701-HauPtPost -0013 PCT / DE2024 / 000006 RUKO GmbH Präzisionswerkzeuge 23.01.2024 RW220052WOP or drive axis A. The polar angle is 45°, which means that the exemplary countersinking tool can be used to produce typical countersinks for screw heads with a taper angle of 90°±1, particularly according to ISO 7721. In the exemplary countersinking tool, the four cutting edges 4 and 5 lie on a truncated cone. Since all cutting edges 4 and 5 sweep over geometrically identical screw surfaces during the feed of the countersinking tool, different chip thicknesses result at the four cutting edges 4 and 5. The chip thickness resulting from each cutting edge is linearly dependent on the pitch angle to the cutting edge preceding it in the direction of rotation. Accordingly, the relatively thickest chip is produced at the cutting edge because the cutting edge preceding it in the direction of rotation is beveled by the largest pitch angle, namely 105°. °offset. The comparatively thinnest chip is produced at the cutting edge, and the thickness of the chips produced at the cutting edges is evenly distributed between the largest and smallest values ​​due to the uniform gradation of the exemplary pitch angles. In an alternative embodiment, the cutting edge arrangement can be designed such that the cutting edges are offset in the direction of the rotation and drive axis. The offset can obviously be selected such that the same chip thickness results on all cutting edges of the cutting edge arrangement. The exemplary countersinking tool also has short secondary cutting edges located behind the four cutting edges 6 in the feed direction, of which only the left-hand secondary cutting edge is designated in the figure. Hau25-01-2024-38503701-HauPtPost -0014 PCT / DE2024 / 000006 RUKO GmbH Precision Tools 23.01.2024 RW220052WOP. The secondary cutting edges are approximately parallel to the rotation or drive axis and serve to form a smooth cylindrical surface on the workpiece material outside the diameter of the cutting edges 5. This means that cylindrically deepened countersinks can also be produced directly with the exemplary countersinking tool. According to Fig. 2, cutting edges 4, 5 can be aligned such that their extensions intersect the rotation or drive axis A. Alternatively, the cutting edges can be aligned such that their extensions run skewed to the rotation or drive axis A. The specialist will determine the alignment one way or another depending on the main application in order to achieve a more or less "pulling" cut.The cutting edges 5 are arranged in pairs offset from one another by four different partial angles around the rotational or drive axis A. In particular, according to Fig. it can be seen that the first cutting edge and the second cutting edge are offset from one another by a partial angle of 75. Furthermore, according to Fig. it can be seen that the second cutting edge and the third cutting edge are offset from one another by a partial angle of 85. Furthermore, according to Fig. it can be seen that the third cutting edge and the fourth cutting edge are offset from one another by a partial angle of 95. Finally, according to Fig. 2 it can be seen that the fourth cutting edge and the first cutting edge are offset from one another by a partial angle of 105. Furthermore, according to Fig. 2 it can be seen that the second cutting edge and the fourth cutting edge are offset from one another by a cumulative partial angle of 180. A first pair of cutting edges is therefore exactly diametrically opposed to the rotational... Hau2E-01-2024-36503701-HauPtPmst -001S PCT / DE2024 / 000006 RUKO GmbH Precision Tools January 23, 2024 RW220052WOP or drive axis A. The second pair of cutting edges, namely the first cutting edge and the third cutting edge, are offset from each other by a cumulative pitch angle of 160° in the direction of rotation of the tool. The exemplary countersinking tool can be formed in one piece in a manner known per se. In particular, the exemplary countersinking tool can be produced from a prefabricated blank by grinding. The cutting edges 4, 5 can be produced, for example, by grinding four chip flutes 10, 11, 12. The chip flutes 10, 11, and 12 can have largely identical profiles, as shown in the example, and in particular, cover the same angle. The blank can be a pre-hardened turning body made of tool steel or a sintered carbide composite.The surface of the finished countersinking tool can also be provided with an additional hardening layer by deposition of a coating from the gas phase.

[0002] Hau 25-01-2024-38S03701 -HauPtPost -0018 PCT / DE2024 / 000006 RUKO GmbH Precision Tools 23.01.2024 RW220052WOP List of reference symbols Countersinking tool 2 Connection point 3 Cutting edge arrangement 4, 5, 6, Cutting edges 9, 10, 11, 12 Chip grooves

Claims

Hau2S-01-2024-3G503701—HamPtPost -0018 PCT / DE2024 / 000006 RUKO GmbH Präzisionswerkzeuge 23.01.2024 RW220052WOP Patent claims 1. Countersinking tool (1), having a connection point (2) for introducing a torque with respect to an axis (A) by a drive device, further comprising a cutting edge arrangement (with a first cutting edge (a second cutting edge (5), a third cutting edge (and a fourth cutting edge (7), wherein the cutting edges are uniformly set at a polar angle (of 45°) with respect to the axis (A) and are arranged rotationally offset from one another in pairs by four partial angles with respect to the axis (A), wherein the four partial angles increase in sequence and the smallest partial angle between the first cutting edge (and the second cutting edge (is between 74° and 76°).

2. Countersinking tool ( according to claim 1 ), wherein the pitch angle between the second cutting edge ( and the third cutting edge ( is between 84 and 86). 3.Countersinking tool ( according to one of the preceding claims, wherein two consecutive partial angles add up to 180.

4. Countersinking tool ( according to claim 1 or 2), wherein the partial angle between the third cutting edge ( and the fourth cutting edge ( is between 102 and 106).

5. Countersinking tool ( according to one of the preceding claims, wherein the cutting edges ( 4, lie on a common cone or truncated cone, the central axis of which coincides with the axis ( A). Countersinking tool ( according to one of the preceding claims, wherein the connection point ( a cylindrical,. Hau25-01-2024-3FM3701 -HauPtPost -0019 PCT / DE2024 / 000006 RUKO GmbH Präzisionswerkzeuge 23.01.2024 RW220052WOP round, flattened, polygonal, hexagonal or otherwise prismatically shaped clamping pin.

7. Countersinking tool (according to one of the preceding claims, wherein the cutting edge arrangement (is formed integrally with the connection point (2).

8. Cutting tool (according to claim 8, wherein the cutting edge arrangement (comprises four substantially equally wide and identically shaped chip flutes (8, 10, 11).

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