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. It has a coupling pin onto which outer cover surfaces and torque surfaces are formed as clamping surfaces. The coupling pin has a particular circular groove, which divides the cutting head into a front pin part and a rear pin part. Stop surfaces for an axial pullout safety are formed in the transition area between the two parts. The torque surfaces and the clamping surfaces are arranged in different pin parts. 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 cutting part in an axial front area, to which is attached contrary to the axial direction a coupling pin with an outer cover surface that runs in a peripheral direction; torque surfaces and clamping surfaces formed on the outer cover surface; a groove inserted into the coupling pin such that forms a front pin part, a rear pin part when viewed in the axial direction, and a stop surface for an axial pullout safety effective in the axial direction, wherein at least one type of function surface is formed on the rear pin part.

2. The cutting head according to claim 1, wherein the one type of function surfaces is formed on the front pin part and the other type of function surfaces is formed on the rear pin part.

3. The cutting head according to claim 1, wherein the torque surfaces are formed on the rear pin part.

4. The cutting head according to claim 1, wherein the groove runs transverse to the axial direction.

5. The cutting head according to claim 1, wherein the stop surface runs under a first angle of inclination at an incline to the axial direction.

6. The cutting head according to claim 5, wherein the first angle of inclination ranges from 30 to 85.

7. The cutting head according to claim 6, wherein the first angle of inclination ranges from 40 to 60.

8. The cutting head according to claim 1, wherein the stop surface runs in a circle, except for any interruption by a clamping slot surrounding the coupling pin in a peripheral direction.

9. The cutting head according to claim 1, wherein the at least one type of the function surface runs parallel to the axial direction.

10. The cutting head according to claim 1, wherein two types of function surfaces run parallel to the axial direction.

11. The cutting head according to claim 1, wherein the one type of the function surfaces is at an incline to the axial direction under a second angle of inclination.

12. The cutting head according to claim 12, wherein the second angle of inclination ranges from 10 to 45 and in particular ranges from 20 to 30.

13. The cutting head according to claim 1, wherein the one type of the function surface is inclined so as to be inclined against the axial direction onto the axis of rotation.

14. The cutting head according to claim 1, wherein the one type of function surface is a torque surface.

15. The cutting head according to claim 1, wherein the coupling pin is square, with a convexly rounded front side and long sides running in a straight line, wherein each long side is preferably interrupted by a respective clamping slot and that the torque surfaces are formed on the long sides and the clamping surfaces are formed on the front sides.

16. The cutting head according to claim 1, wherein the two pin parts extend in an axial direction across a comparable length.

17. The cutting head according to claim 1, wherein both types of function surfaces are formed on the rear pin part.

18. The cutting head according to claim 17, wherein the 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.

19. A rotary tool extending in an axial direction along an axis of rotation comprising two coupling parts including a support and a cutting head, the cutting head interchangeably fastened to the support, wherein the support has front-side fastening bars with inner cover surfaces, which limits a pin hole; a coupling pin of the cutting head can be clamped into the pin hole by rotating the cutting head in relation to the support, and the coupling pin has outer cover surfaces; two different types of corresponding function surfaces that lie opposite each other in pairs in the assembled state, namely torque surfaces for transmitting torque, as well as clamping surfaces for transmitting a radial clamping force formed on the inner cover surfaces and on the outer cover surfaces; a groove inserted into the coupling pin such that forms a front pin part, a rear pin part when viewed in the axial direction, and a stop surface for an axial pullout safety effective in the axial direction, wherein at least one type of function surface is formed on the rear pin part.

20. The rotary tool according to claim 19, wherein the one type of function surfaces is formed on the front receiving part and the other type of function surfaces is formed on the rear receiving part.

21. The rotary tool according to claim 19, wherein the fastening bars are limited by a top front contact surface; and wherein the pin hole is limited by a base; and wherein the pin hole extends from the front contact surfaces up to the base across a length; and wherein the cutting head has front cutting part attached to which is the coupling pin; and wherein a head-bearing surface formed in the transition to the coupling pin; and wherein the coupling pin extends across a pin length from the head-bearing surface up to a pin base; and wherein the pin length according to a first variant is longer than the length of the pin hole and the pin length according to a second variant is shorter than the length of the pin hole.

22. The rotary tool according to claim 19, wherein the coupling pin has both in the area of the clamping surfaces and in the area of the torque surfaces an excess in relation to the pin hole, wherein the excess in the area of the torque surfaces is smaller than the excess in the area of the torque surfaces.

23. A support for a rotary tool as recited in claim 19, which is formed for the accommodation of a cutting head as recited in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] 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;

[0055] 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;

[0056] FIG. 2A is a perspective view of the cutting head of the first design variant;

[0057] FIG. 2B is a bottom-side view of the cutting head according to FIG. 2A;

[0058] FIGS. 2C, 2D are in each instance side views of the cutting head according to FIG. 2A rotated toward one another at 90;

[0059] 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;

[0060] FIG. 3B is a top view of the support according to FIG. 3A;

[0061] FIG. 3C is a sectional view along lines of intersection C-C in FIG. 3B;

[0062] FIG. 3D is a top view of the support according to FIG. 3A;

[0063] FIG. 3E is a sectional view through the support according to sectional line E-E in FIG. 3D;

[0064] FIG. 4A is a perspective view of the support according to a first alternative with a partially extending clearance;

[0065] FIG. 4B is a perspective view of the support according to a second alternative with a clearance that extends over an entire fastening bar;

[0066] FIG. 5A is a side view of a first embodiment, in which the coupling pin is shorter than the pin hole;

[0067] FIG. 5B is a side view of a second embodiment, in which the coupling pin is longer than the pin hole;

[0068] FIG. 6A is a perspective view of the cutting head of a second design variant of the rotary tool;

[0069] FIG. 6B is a sectional view of the support of the second design variant for accommodating the cutting head according to FIG. 6A;

[0070] FIG. 7A is a third variant of the rotation tool as shown in perspective;

[0071] 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

[0072] 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

[0073] 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.

[0074] 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 clamping slots 16 that start in the cutting head 12 and merge into the support 10. In the exemplary embodiment, the clamping slots 16 are roughly spiral in shape. The support 10 is a grooved shaft section in which secondary cutting edges, which extend, for example, along the clamping slots 16 and start at the cutting head 12, continue. A non-grooved tightening section is typically attached to a grooved shaft section of the support 10, with which the rotary tool 2 is clamped into a machine tool.

[0075] 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.

[0076] The support 10 has on its front side two roughly diagonal, opposite-facing fastening bars 18 that are interrupted by the clamping slots 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.

[0077] The circumference of the pin hole 20 is limited by inner cover 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 running 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.

[0078] On the inner cover surfaces 24a, the support 10 has in each instance torque sections 30a and clamping sections 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 section. Directly attached to the base 25a are groove-like indentations 36 in the inner cover surfaces 24a, which forms a projection. This projection forms on its bottom side aligned to the indentation preferably horizontally extending stop surfaces 38a.

[0079] The groove-like indentation 36 formed as a type of recess divides the pin hole 20 into two parts, namely a front receiving part 40a and a rear receiving part 42a.

[0080] Corresponding to the pin hole 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 pin hole 20, the coupling pin 40 has outer cover sections 24b, on which also are formed torque sections 30b and clamping sections 32b. These sections 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 section.

[0081] 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 clamping slots 16.

[0082] Inserted into the coupling pin 14 is a particularexcept for the recesses caused by the clamping slots 16circumferential groove 37 that divides the coupling pin into two parts, namely a front pin part 40b and a rear pin part 42b.

[0083] 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 sections 32a and b.

[0084] 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 pin hole 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 section formed by the clamping slots 16. Formed on the long sides or narrow sides of this roughly rectangular transverse section are the torque sections 30a and b, and formed on the front sides are the clamping sections 32a and b. The clamping sections 32a and b runfor 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 section are rounded off.

[0085] 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 clamping slots 16. The two parts (pin parts and receiving parts) 40a and b and 42a and b form two function zones or functional levels that are offset to one another in axial direction 4. In the front part 40a and b are formed the clamping surfaces 32a and b, and in the rear part 42a and b are formed the torque surfaces 30a and b.

[0086] As is clear in particular from the top views of FIGS. 2B and 3B, the torque surfaces 30a and b are formed on the long sides of the approximately square basic geometry of the pin hole 20 and of the coupling pin 14. The clamping surfaces 32a and b are on the other hand formed on the front sides of the square basic geometry.

[0087] 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.

[0088] The rear pin part 42b extends in an axial direction across a part length I2 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 I2.

[0089] The part length I2 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.

[0090] In the first exemplary embodiment according to FIGS. 1 through 4, both the torque surfaces 30a and b and the clamping surfaces 32a and b run parallel to the axial direction. Thus, they are not inclined in relation to the axial direction. The stop surfaces 38a and b preferably run 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 it is at approximately 70.

[0091] Alternatively, the stop surfaces 38a and b run in a horizontal direction perpendicular to the axial direction.

[0092] The stop surfaces 38a and b are generally clamped by a direction along the circumference of the coupling pin 14 or of the pin hole 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 section runs along a circular arc line around the axis of rotation 6, the transverse direction will correspond to the radial direction.

[0093] The stop surfaces 38a and b extend in a longitudinal direction that typically measures a few millimeters, for example 0.5 mm to 2 mm.

[0094] The transition areas between various lateral surfaces 30a and b, 32a and b in an axial direction to the adjacent surfaces 22a and b, 38a and b, and 25a and b, are in each instance rounded or tapered.

[0095] 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 cover 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.

[0096] 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.

[0097] FIGS. 5A and 5B show two different embodiments, in which the two coupling parts (coupling pin 14, pin hole 20) in the joined state contact the front or head-bearing surfaces 22a and b (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.

[0098] 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.

[0099] Due to the arrangement of the torque surfaces 30a and b in the rear part 42a and b, the torque surfaces 30a and b 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, it is approximately at 25. The oblique torque surfaces 30a and b improve the transmission of force in axial direction 4 into the support 10. The torque surfaces 30a and b and generally the inner cover 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 runs parallel to the axial direction.

[0100] For assembling the cutting head 12, it first is inserted forward into the pin hole 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 pin hole 20. In this connection, the stop surfaces 38a and b form a positive rear grip for an axial pullout safety. The clamping sections 32a and b also form a press fit and thus a clamp. In this connection, a radial clamping force is applied to the clamping sections 32a and b from the fastening bars 18 onto the coupling pin 14. In the end position, the corresponding torque sections 30a and b also come to rest together. In operation, force applied from the support 10 is transmitted via the torque sections 30a and b onto the cutting head 12.

[0101] 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 I3 and the pin hole 20 has a length I4 auf. In the first embodiment, the pin length I3 is shorter than the length I4. In the second embodiment, it is the reverse.

[0102] 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 b and clamping surfaces 32a and b, as well as the separately formed axial pullout safety in the form of the stop surfaces 38a and b.

[0103] 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 b and clamping surfaces 32 a and b 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 tranverse section 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.

[0104] 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 b and 32a and b, can be increased. [000105] As in the preceding exemplary embodiments, the groove 37 connects directly to the head-bearing surface 22b. The stop surfaces 38b in turn run perpendicular to the axial direction 4 or inclined in relation to it. The pin hole 20 is also formed in accordance with the design of the coupling pin 14.

[0105] The patents and publications referred to herein are hereby incorporated by reference.

[0106] Having described presently preferred embodiments the invention may be otherwise embodied within the scope of the appended claims.