Cutting head, rotary tool and support for the rotary tool and for the accommodation of the cutting head

Abstract

A cutting head is formed for insertion into a support in a modular rotary tool, in particular a drill. The coupling head has a coupling having torque surfaces and clamping surfaces on its outer periphery. The coupling pin is divided into a front pin part and a rear pin part. The front pin part is defined by a circumferential groove. Stop surfaces for an axial pullout safety are formed in the transition area between the two the front pin part and the rear pin part. The torque surfaces and the clamping surfaces are arranged in different pin parts. For example, the clamping surfaces are preferably formed on the front pin part and the torque surfaces are preferably formed in the rear pin part.

Claims

1. A cutting head for a rotary tool extending in an axial direction along an axis of rotation, comprising: a front cutting part; a coupling pin having an outer peripheral surface, the outer peripheral surface divided into a front pin part and a rear pin part, the front pin part comprising a circumferential groove; and a stop surface for preventing axial pullout of the cutting head in the axial direction, wherein the coupling pin includes a torque surface formed on the rear pin part, and wherein the coupling pin includes a clamping surface formed on the circumferential groove of the front pin part, and wherein the clamping surface has an angle of inclination of zero degrees with respect to the axis of rotation; wherein, when viewed with respect to a plane transverse to the axis of rotation: the clamping surface is curved and defines an arc; and at least a portion of the torque surface is disposed radially inwardly with respect to the arc defined by the clamping surface.

2. The cutting head according to claim 1, wherein the circumferential groove extends transverse to the axial direction.

3. The cutting head according to claim 1, wherein the stop surface is formed at a first angle of inclination at an incline to the axial direction.

4. The cutting head according to claim 3, wherein the first angle of inclination ranges from 30 to 85.

5. The cutting head according to claim 4, wherein the first angle of inclination ranges from 40 to 60.

6. The cutting head according to claim 1, wherein the stop surface extends circumferentially, except for any interruption by a flute surrounding the coupling pin in a peripheral direction.

7. The cutting head according to claim 1, wherein the torque surface is formed with a second angle of inclination with respect to the axis of rotation.

8. The cutting head according to claim 1, wherein the front pin part has a first length in the axial direction, and wherein the rear pin part has a second length in the axial direction, and wherein the first length is identical to the second length.

9. The cutting head according to claim 1, wherein the circumferential groove has a groove length and the rear pin part has a part length, wherein the groove length ranges from 0.3 to 0.5 times the part length.

10. A rotary tool extending in an axial direction along an axis of rotation, comprising: a support, comprising: a pair of opposing fastening bars, each fastening bar having an inner peripheral surface defining a coupling pin receptacle, the inner peripheral surface divided into a front receiving part and a rear receiving part, the rear receiving part comprising a groove-like indentation; and a cutting head capable of being received in the coupling pin receptacle of the support, the cutting head comprising: a front cutting part; a coupling pin having an outer peripheral surface, the outer peripheral surface divided into a front pin part and a rear pin part, the front pin part comprising a circumferential groove; and a stop surface for preventing axial pullout of the cutting head in the axial direction, wherein the coupling pin includes a torque surface formed on the rear pin part, and wherein the coupling pin includes a clamping surface formed on the circumferential groove of the front pin part, and wherein the clamping surface has an angle of inclination of zero degrees with respect to the axis of rotation; wherein, when viewed with respect to a plane transverse to the axis of rotation: the clamping surface is curved and defines an arc; and at least a portion of the torque surface is disposed radially inwardly with respect to the arc defined by the clamping surface.

11. The rotary tool according to claim 10, wherein a first type of function surface is formed on the front receiving part and a second type of function surface is formed on the rear receiving part.

12. The rotary tool according to claim 10, wherein the coupling pin has a pin length, and wherein the coupling pin receptacle has a coupling pin receptacle length.

13. The rotary tool according to claim 12, wherein the pin length is equal to the coupling pin receptacle length.

14. The rotary tool according to claim 12, wherein the pin length is shorter than the coupling pin receptacle length.

15. The rotary tool according to claim 12, wherein the pin length is greater than the coupling pin receptacle length.

16. The rotary tool according to claim 10, wherein the torque surface is formed with a second angle of inclination with respect to the axis of rotation.

17. The cutting head according to claim 1, wherein, when viewed with respect to a plane transverse to the axis of rotation, the clamping surface is convexly curved.

18. The cutting head according to claim 17, wherein, when viewed with respect to a plane transverse to the axis of rotation, the arc is circular or elliptical.

19. The cutting head according to claim 1, wherein, when viewed with respect to a plane transverse to the axis of rotation, the torque surface is straight.

20. The cutting head according to claim 1, comprising: a flute disposed in the coupling pin; wherein the torque surface terminates at the flute.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention are described in detail by the use of figures. In the figures, identically acting parts are given the same reference numbers.

(2) FIG. 1A is a perspective, exploded view of a section of a rotary tool with a support and a cutting head according to a first design variant;

(3) FIG. 1B is a perspective view of a section of the rotary tool according to FIG. 1A where the cutting head is inserted in the support;

(4) FIG. 2A is a perspective view of the cutting head of the first design variant;

(5) FIG. 2B is a bottom-side view of the cutting head according to FIG. 2A;

(6) FIGS. 2C, 2D are in each instance side views of the cutting head according to FIG. 2A rotated toward one another at 90;

(7) FIG. 3A is a perspective view of a support according to a first design variant for accommodating the cutting head according to FIGS. 2A through 2D for the rotary tool described in FIGS. 1A and 1B;

(8) FIG. 3B is a top view of the support according to FIG. 3A;

(9) FIG. 3C is a sectional view along lines of intersection C-C in FIG. 3B;

(10) FIG. 3D is a top view of the support according to FIG. 3A;

(11) FIG. 3E is a sectional view through the support according to sectional line E-E in FIG. 3D;

(12) FIG. 4A is a perspective view of the support according to a first alternative with a partially extending clearance;

(13) FIG. 4B is a perspective view of the support according to a second alternative with a clearance that extends over an entire fastening bar;

(14) FIG. 5A is a side view of a first embodiment, in which the coupling pin is shorter than the coupling pin receptacle;

(15) FIG. 5B is a side view of a second embodiment, in which the coupling pin is longer than the coupling pin receptacle;

(16) FIG. 6A is a perspective view of the cutting head of a second design variant of the rotary tool;

(17) FIG. 6B is a sectional view of the support of the second design variant for accommodating the cutting head according to FIG. 6A;

(18) FIG. 7A is a third variant of the rotation tool as shown in perspective;

(19) FIG. 7B, C is a side view and a bottom-side top view of a cutting head of the third variant of the rotation tool according to FIG. 7A; and

(20) FIG. 7D, E is a top view and a sectional view along the cutting line E-E in FIG. 7D of the support of the third variant of the rotation tool according to FIG. 7A.

DETAILED DESCRIPTION OF THE INVENTION

(21) The rotary tool 2 shown in the figures is formed as a modular drilling tool. It extends in an axial direction 4 along an axis of rotation 6. Around the axis of rotation 6 rotates the rotary tool 2 during normal operation in the direction of rotation, which at the same time defines a peripheral direction 8.

(22) The rotary tool 2 consists of a support 10 and a cutting head 12 that can be interchangeably fastened to it. The cutting head 12 has a front cutting part 13 and a coupling pin 14 connected to it. The cutting part 13 is limited on the front side by an anterior front surface and in this instance, does not have precisely calculated main cutting edges, which typically are connected to one another in the center of a drill front via a transverse cut and extend radially outward. Main cutting edges are connected to the main free areas on the front contrary to the direction of rotation and peripheral direction 8. On its circumference, the cutting head 12 has a ridge 15 that is interrupted by opposite-facing flutes 16 that start in the cutting head 12 and merge into the support 10. In the exemplary embodiment, the flutes 16 are roughly spiral in shape. The support 10 is a grooved shaft surface in which secondary cutting edges, which extend, for example, along the flutes 16 and start at the cutting head 12, continue. A non-grooved tightening surface is typically attached to a grooved shaft surface of the support 10, with which the rotary tool 2 is clamped into a machine tool.

(23) Elements on the support 10 that correspond to one another are identified below with the letter a and on the cutting head 12 with the letter b.

(24) The support 10 has on its front side two roughly diagonal, opposite-facing fastening bars 18 that are interrupted by the flutes 16. The fastening bars 18 extend in a peripheral direction 8 in each instance across an angular range of approximately 70 to 90. The front of each fastening bar 18 is limited by flat front contact surfaces 22a, which are arranged in the exemplary embodiment within a common horizontal plane to which the axis of rotation 6 is thus vertically aligned.

(25) The circumference of the coupling pin receptacle 20 is limited by inner peripheral surfaces 24a of the fastening bars 18. It is also limited on its bottom side by a base 25a running horizontally, i.e. perpendicular to the axis of rotation 6. Inserted into this base 25a concentric to the axis of rotation 6 is a centering hole 26a. Also extending in the exemplary embodiment 2 are coolant channels 28 in the support 10, which escape through the bottom surface and align there with corresponding coolant channels 28 of the cutting head 12.

(26) On the inner peripheral surfaces 24a, the support 10 has in each instance torque surfaces 30a and clamping surfaces 32a, which are aligned in the axial direction 4 offset to one another and followviewed in a projection in axial direction 4one another in peripheral direction 8 under an intermediate arrangement of a transition surface. Directly attached to the base 25a are groove-like indentations 36 in the inner peripheral surfaces 24a, which forms a projection. This projection forms on its bottom side aligned to the indentation preferably horizontally extending stop surfaces 38a.

(27) The coupling pin receptacle 20 is divided into two parts, namely a front receiving part 40a and a rear receiving part 42a. The rear receiving part 42a comprises a groove-like indentation 36, which is interrupted by the flutes 16.

(28) Corresponding to the coupling pin receptacle 20, the cutting head 12 has the coupling pin 14, which extends in axial direction 4. The coupling pin 14 is radially offset backwards in a radial direction from the peripheral surfaces of the ridge 15. Corresponding to the coupling pin receptacle 20, the coupling pin 40 has outer peripheral surfaces 24b, on which also are formed torque surfaces 30b and clamping surfaces 32b. These surfaces are aligned in the axial direction 4 offset to one another and followviewed in a projection in axial direction 4one another in peripheral direction 8 under an intermediate arrangement of a transition surface.

(29) The radially offset backwards coupling pin 14 forms in the transitions from the cutting part 13 to the coupling pin 14 a radial projection to the ridge 14, as a result of which two head-bearing surfaces 22b are formed that are in turn arranged in a common horizontal plane and which are separated by the flutes 16.

(30) The coupling pin 14 is divided into two parts, namely a front pin part 40b and a rear pin part 42b. The front pin part 40b comprises a circumferential groove 37, which is interrupted by the flutes 16.

(31) Also formed concentrically to the axis of rotation 6 on the coupling pin 14 is an insertion pin 26b, which is formed solely for use in the support 10 as a first centering aid of the cutting head 12. The cutting head 12 is actually centered by the clamping surfaces 32a and 32b.

(32) As is clear in particular from the top views of the cutting head 12 according to FIG. 2A and the top view of the support 10 according to FIGS. 3A and 4A, the coupling pin 40 and the coupling pin receptacle 20 are essentially rectangular and thus have a roughly block-like shape. The coupling pin 14 therefore has, in particular, long sides extending in a straight line and convex, curved front sides, except for, however, diagonal, opposite-facing areas of the long sides of the roughly square transverse surface formed by the flutes 16. Formed on the long sides or narrow sides of this roughly rectangular transverse surface are the torque surfaces 30a and 30b, and formed on the front sides are the clamping surfaces 32a and 32b. The clamping surfaces 32a and 32b extendfor example viewed in a cross-section perpendicular to axial direction 4along a circular arc or along an elliptical arc. The corner areas of the roughly rectangular transverse surface are rounded off.

(33) In the exemplary embodiments, the groove 37 and the groove-like indentation 36 in each instance extend completely circumferentially and in each instance lead into the flutes 16. The two parts (pin parts and receiving parts) 40a and 40b and 42a and 42b form two function zones or functional levels that are offset to one another in axial direction 4. In the front part 40a and 40b are formed the clamping surfaces 32a and 32b, and in the rear part 42a and 42b are formed the torque surfaces 30a and 30b.

(34) As is clear in particular from the top views of FIGS. 2B and 3B, the torque surfaces 30a and 30b are formed on the long sides of the approximately square basic geometry of the coupling pin receptacle 20 and of the coupling pin 14. The clamping surfaces 32a and 32b are on the other hand formed on the front sides of the square basic geometry.

(35) The groove 37 passesviewed in axial direction 4on the end side preferably across rounded transition areas in the head-bearing surfaces 22b extending radially outwards and in the backward area passes into the stop surfaces 38b. The groove 37 has a groove length 11 that is defined by the distance between the head-bearing surfaces 22b and the stop surface 38b. At the same time, the groove length 11 also defines in this respect an axial length of the front pin part 40b. In the same manner, the front receiving part 40a also has a length corresponding to the groove length 11.

(36) The rear pin part 42b extends in an axial direction across a part length 12 that is defined by the distance between the stop surfaces 38b and the base 25b. In the same manner, the rear receiving part 42a has a length corresponding to the part length 12.

(37) The part length 12 and the groove length 11 are roughly the same, and preferably identical. They preferably differ by no more than 30%. They generally range, for example in the case of a rotation tool 2 with a nominal diameter of 16 mm, between typically 2 mm and 5 mm, and in particular measure approximately 3 mm (+/0.5 mm). For other nominal diameters, the respective part length is correspondingly adjusted so that the ratio of nominal diameter to part or groove length remains the same.

(38) In the first exemplary embodiment, according to FIGS. 1 through 4, both the torque surfaces 30a and 30b and the clamping surfaces 32a and 32b extend parallel to the axial direction. Thus, they are not inclined in relation to the axial direction. The stop surfaces 38a and 38b preferably extend under a first angle of inclination, 1, inclined in relation to axial direction 4 (see FIG. 1A). The first angle of inclination, 1, preferably ranges between 30 and 85 and in particular between 50 and 75. In the exemplary embodiment, the first angle of inclination, 1, is at approximately 70.

(39) Alternatively, the stop surfaces 38a and 38b extend in a horizontal direction perpendicular to the axial direction.

(40) The stop surfaces 38a and 38b are generally clamped by a direction along the circumference of the coupling pin 14 or of the coupling pin receptacle 20 and a transverse direction that is aligned perpendicular to the direction along the circumference. At the same time, this transverse direction is inclined with regard to axial direction 4 under the first angle of inclination, 1. If a circumferential surface extends along a circular arc line around the axis of rotation 6, the transverse direction will correspond to the radial direction.

(41) The stop surfaces 38a and 38b extend in a longitudinal direction that typically measures a few millimeters, for example 0.5 mm to 2 mm.

(42) The transition areas between various lateral surfaces 30a and 30b, 32a and 32b in an axial direction to the adjacent surfaces 22a and 22b, 38a and 38b, and 25a and 25b, are in each instance rounded or tapered.

(43) FIGS. 4A and 4B show two alternatives for the support 10, in which a clearance 44 is formed in the transition area from the base 25a to the inner peripheral surfaces 24a of the bottom receiving part 42a. To that end, material in the corner and transition area is removed, for example with the help of a grinding wheel or milling head.

(44) In the design variant according to FIG. 4A, the clearance 44, in this instance starting from the clamping slot 16, extends contrary to rotation and peripheral direction 8 only across part of the respective fastening bar 18, and indeed in particular across the area in which the clamping surfaces 32a are formed. In contrast to this, the clearance 44 in the design variant according to FIG. 4B extends across the entire angular range of the fastening bar 18, therefore extending from a clamping slot 16 up to the opposite-facing clamping slot.

(45) Figures FIGS. 5A and 5B show two different embodiments, in which the two coupling parts (coupling pin 14, coupling pin receptacle 20) in the joined state contact the front or head-bearing surfaces 22a and 22b (FIG. 5A) once and the bottom surfaces (pin base 25a, base 25b, FIG. 5B) once. Both embodiments can also be constructed like the first design variant.

(46) A second design variant of the rotary tool 2 is shown in FIGS. 6A and 6B. The basic difference with regard to the first design variant according to FIGS. 1A and 1B is that the rear pin part 42b and the rear receiving part 42a are aligned together at an oblique incline with regard to axial direction 4; they taper off contrary to axial direction 4. In addition, in the case of this design variant, no centering hole 26a or centering pin 26b is shown. Otherwise, the second design variant corresponds to the first design variant. With regard to the corresponding features, please refer to the description of the first design variant.

(47) Due to the arrangement of the torque surfaces 30a and 30b in the rear part 42a and 42b, the torque surfaces 30a and 30b are aligned together at an oblique incline with regard to axial direction 4 under a second angle of inclination, 2 (see FIG. 6B). This second angle of inclination, 2, preferably ranges from 10 to 45 and in particular ranges from 20 to 30. In the exemplary embodiment, the second angle of inclination, 2, is approximately at 25. The oblique torque surfaces 30a and 30b improve the transmission of force in axial direction 4 into the support 10. The torque surfaces 30a and 30b and generally the inner peripheral surfaces 24a are in general clamped by a direction along the circumference and a longitudinal direction aligned perpendicular to it. This longitudinal direction is aligned with regard to axial direction 4 under the second angle of inclination, 2. If the second angle of inclination, 2, is zero, the longitudinal direction extends parallel to the axial direction.

(48) For assembling the cutting head 12, it first is inserted forward into the coupling pin receptacle 20 in axial direction 4 along with its coupling pin 14. In this connection, it is, in contrast to the position shown in FIGS. 1A and 1B, rotated by approximately 90. For this first axial insertion, the insertion pin 26b provides a first centering support. Then, the entire cutting head 12 is rotated contrary to rotation and peripheral direction 8 around the axis of rotation 6 within the coupling pin receptacle 20. In this connection, the stop surfaces 38a and 38b form a positive rear grip for an axial pullout safety. The clamping surfaces 32a and 32b also form a press fit and thus a clamp. In this connection, a radial clamping force is applied to the clamping surfaces 32a and 32b from the fastening bars 18 onto the coupling pin 14. In the end position, the corresponding torque surfaces 30a and 30b also come to rest together. In operation, force applied from the support 10 is transmitted via the torque surfaces 30a and 30b onto the cutting head 12.

(49) In the assembled end position, according to the first embodiment shown in FIG. 5A, the head-bearing surfaces 22b lie flat on the front contact surfaces 22a. According to the second embodiment, the pin base 25b lies on the base 25a. To that end, the coupling pin 14 has a pin length 13 and the coupling pin receptacle 20 has a length 14. In the first embodiment, the pin length 13 is shorter than the length 14. In the second embodiment, it is the reverse.

(50) Altogether, an extremely reliable coupling between the cutting part 12 and the support 10 is realized by the design described herein containing the function surfaces separated into different axial function zones, namely torque surfaces 30a and 30b and clamping surfaces 32a and 32b, as well as the separately formed axial pullout safety in the form of the stop surfaces 38a and 38b.

(51) A further, third design variant is shown in FIGS. 7A through 7E in which, in contrast to the preceding variants, both the torque surfaces 30a and 30b and clamping surfaces 32a and 32b are formed on the rear pin part 42b or on the rear receiving part 42a. These surfaces are therefore arranged at the same axial height, but are offset to one another in the peripheral direction 8. The roughly rectangular transverse surface geometry is maintained in the design variants described above. The torque surfaces 30b are thus adjusted to the front sides of the coupling pin 14 on the longitudinal sides and to the clamping surfaces 32b.

(52) In this design variant, the groove 37 has a significantly shorter groove length 11 that preferably ranges from 0.3 to 0.5 times the part length 12. Thus, the part length 12 is generally significantly greater (by at least a factor of 2) than the groove length 11. This makes possible, compared to the preceding exemplary embodiments, on the one hand a short pin length 13, or the part length, 12 and thus the length of the function surfaces 30a and 30b and 32a and 32b, can be increased.

(53) As in the preceding exemplary embodiments, the groove 37 connects directly to the head-bearing surface 22b. The stop surfaces 38b in turn extend perpendicular to the axial direction 4 or inclined in relation to it. The coupling pin receptacle 20 is also formed in accordance with the design of the coupling pin 14.

(54) The patents and publications referred to herein are hereby incorporated by reference.

(55) Having described presently preferred embodiments the invention may be otherwise embodied within the scope of the appended claims.