Device for Transmitting Torque from a Drill to a Drill Bit

Abstract

A device for transmitting a torque produced by a drill includes a shank having a first outer conical region, a groove region, a second outer conical region, and a plurality of first longitudinal grooves extending over the first outer conical region, the groove region, and the second outer conical region and having a plurality of second longitudinal grooves extending over the second outer conical region. A tool fitting has a rotary driving part. The rotary driving part has an inner conical region and an inner driver region where the inner driver region has a plurality of first inner rotary drivers with a first width and first depth and a plurality of second inner rotary drivers with a second width and second depth. The first depth and the second depth are identical and the second longitudinal grooves also extend over the first outer conical region and the groove region.

Claims

1.-4. (canceled)

5. A device (10) for transmitting a torque which is produced by a drill (11) to a drill bit (12), comprising: a shank (14) having a first outer conical region (33), a groove region (34), a second outer conical region (35), and a plurality of first longitudinal grooves (37) extending over the first outer conical region (33), the groove region (34), and the second outer conical region (35) and having a plurality of second longitudinal grooves (38) extending over the second outer conical region (35); and a tool fitting (13) which has a rotary driving part (42) and a locking device (43); wherein the rotary driving part (42) has an inner conical region (48) and an inner driver region (49) and wherein the inner driver region (49) has a plurality of first inner rotary drivers (51) with a first width (B.sub.1) and first depth (T.sub.1) and a plurality of second inner rotary drivers (52) with a second width (B.sub.2) and second depth (T.sub.2); wherein the locking device (43) is adjustable parallel to a longitudinal axis (22) of the tool fitting (13) between a receiving position and a locking position and wherein the shank (14) is insertable into the tool fitting (13) in the receiving position and is connected to the tool fitting (13) in the locking position; wherein, in a connected state of the device (10), the first inner rotary drivers (51) of the rotary driving part (42) engage in the first longitudinal grooves (37) of the shank (14) and the second inner rotary drivers (52) of the rotary driving part (42) engage in the second longitudinal grooves (38) of the shank (14); and wherein the first depth (T.sub.1) of the first inner rotary drivers (51) and the second depth (T.sub.2) of the second inner rotary drivers (52) are identical and wherein the second longitudinal grooves (38) of the shank (14) also extend over the first outer conical region (33) and the groove region (34).

6. The device as claimed in claim 5, wherein the first width (B.sub.1) of the first inner rotary drivers (51) and the second width (B.sub.2) of the second inner rotary drivers (52) are identical.

7. The device as claimed in claim 5, wherein the inner conical region (48) and the inner driver region (49) are formed in one piece.

8. The device as claimed in claim 6, wherein the inner conical region (48) and the inner driver region (49) are formed in multiple pieces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 shows a device according to the invention for transmitting torque from a drill to a drill bit;

[0018] FIGS. 2A, 2B show a tool fitting (FIG. 2A) and a shank (FIG. 2B) of the device according to the invention for transmitting torque that is illustrated in FIG. 1;

[0019] FIGS. 3A, 3B show the shank of the device according to the invention for transmitting torque in a side view (FIG. 3A) and in a longitudinal section along the section plane A-A in FIG. 3A (FIG. 3B);

[0020] FIGS. 4A, 4B show the device according to the invention for transmitting torque of FIG. 1 in the connected state in which the shank of FIG. 2B is connected to the tool fitting of FIG. 2A, in a side view (FIG. 4A) and in a longitudinal section along the section plane A-A in FIG. 4A (FIG. 4B); and

[0021] FIGS. 5A-C show a rotary driving part of the tool fitting in a side view (FIG. 5A), in a longitudinal section along the section plane A-A in FIG. 5A (FIG. 5B) and in a plan view of the interface with the shank (FIG. 5C).

DETAILED DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 shows a device 10 according to the invention for transmitting a torque from a drill 11 to a drill bit 12. The device 10 is arranged between the drill 11 and the drill bit 12 and transmits the torque from the drill 11 to the drill bit 12.

[0023] The device 10 is constructed from a tool fitting 13, which is connected to the drill 11, and a shank 14, which is connected to the drill bit 12. The device 10 is connected to the drill 11 via a first connection 15 and to the drill bit 12 via a second connection 16. In the connected state of the device 10, torque is transmitted via the following components: drive shaft 17 of the drill 11, tool fitting 13, shank 14 and drill bit 12. The connected state of the device 10 is defined as the state in which the tool fitting 13 and the shank 14 are connected.

[0024] FIGS. 2A, 2B show the drill 11 with the tool fitting 13 (FIG. 2A) and the drill bit 12 with the shank 14 (FIG. 2B) of the device 10 according to the invention. The tool fitting 13 and the shank 14, in the connected state, form the device 10 according to the invention of FIG. 1.

[0025] The tool fitting 13 is connected to the drill 11 via the first connection 15, which in the exemplary embodiment is designed as a releasable connection; alternatively, the tool fitting 13 can be connected to the drill 11 via a non-releasable first connection 15. Since the tool fitting 13 is a wearing part, it makes sense to design the tool fitting 13 as a separate component and to connect it to the drive shaft 17 of the drill 11 via a releasable first connection. In order to ensure that the drill 11 is operated only with an approved tool fitting 13, it makes sense to design the first connection 15 in such a way that it can be operated only with a special tool.

[0026] The shank 14 is connected to the drill bit 12 via the second connection 16, which is designed as a releasable connection in the exemplary embodiment. For this purpose, the drill bit 12 has an internal thread which is connected to an external thread of the shank 14. The releasable second connection 16 is designed, for example, as a metric ISO threaded connection or other releasable connection. Instead of the releasable second connection 16, the shank 14 can be connected non-releasably to the drill bit 12; for this purpose, the shank 14 can be connected non-releasably to the drill bit 12, for example by welding or other methods.

[0027] The drive shaft 17 is designed to be rotatable about a first axis of rotation 21 which, in the connected state of the tool fitting 13 and the drill 11, coincides with a longitudinal axis 22 of the tool fitting 13. The drill bit 12 is designed to be rotatable during operation about a second axis of rotation 23 which, in the connected state of the shank 14 and the drill bit 12, coincides with a longitudinal axis 24 of the shank 14. For differentiation purposes, the longitudinal axis 22 of the tool fitting 13 is referred to as the first longitudinal axis 22 and the longitudinal axis 24 of the shank 14 is referred to as the second longitudinal axis 24. In the connected state of the drill 11 and the drill bit 12, the first longitudinal axis 22 and second longitudinal axis 24 are arranged coaxially to one another.

[0028] FIGS. 3A, 3B show the shank 14 of the device 10 according to the invention for transmitting torque in the non-connected state of the device 10 in a side view (FIG. 3A) and in a longitudinal section along the section plane A-A in FIG. 3A (FIG. 3B). The shank 14 is constructed from a first portion 26 and a second portion 27, which in the exemplary embodiment are formed in one piece and have a central through-hole 28.

[0029] The second portion 27 of the shank 14 has an external thread 29, forming the second threaded connection 16 with a matching internal thread of the drill bit 12. The first portion 26 of the shank 14 is composed of five portions and includes a front region 32, a first outer conical region 33, a groove region 34, a second outer conical region 35 and a cylinder region 36. The first and second outer conical region 33, 35 have a first or second conical outer surface which widens in the direction of the drill bit 12. The conical outer surfaces are produced for example by turning; by manufacturing the first and second conical outer surface in one setting, high manufacturing accuracy can be achieved.

[0030] The shank 14 has a plurality of first longitudinal grooves 37 and a plurality of second longitudinal grooves 38, which extend parallel to the second longitudinal axis 24 of the shank 14 and are arranged on the outside of the first portion 26. The first longitudinal grooves 37 and second longitudinal grooves 38 are identically formed and extend over the first outer conical region 33, the groove region 34 and the second outer conical region 35 and also over the cylinder region 36. The first longitudinal grooves 37 and second longitudinal grooves 38 are uniformly distributed in a circumferential direction 39 of the shank 14 and are arranged alternately, each first longitudinal groove 37 being arranged between two second longitudinal grooves 38. In the exemplary embodiment, the shank 14 has three first longitudinal grooves 37 and three second longitudinal grooves 38; it generally applies that the number of the plurality of first longitudinal grooves 37 is identical to the number of the plurality of second longitudinal grooves 38.

[0031] FIGS. 4A, 4B show the device 10 according to the invention for transmitting torque in the connected state, in which the shank 14 is connected to the tool fitting 13, in a side view (FIG. 4A) and in a longitudinal section along the section plane A-A in FIG. 4A (FIG. 4B).

[0032] The tool fitting 13 is constructed from a rotary driving part 42 and a locking device 43. The locking device 43 is designed to be adjustable relative to the rotary driving part 42, wherein the locking device 43 is designed to be displaceable in a longitudinal direction 44 that runs parallel to the first longitudinal axis 22 of the tool fitting 13, and to be rotatable about the first longitudinal axis 22 of the tool fitting 13. The locking device 43 is adjustable between a plurality of positions, which are referred to as the basic position, receiving position and locking position.

[0033] In order to be able to connect the shank 14 to the tool fitting 13 in a form-fitting manner, the locking device 43 is shifted from the basic position in the longitudinal direction 44 into the receiving position. In the receiving position, the shank 14 is inserted into the tool fitting 13. To lock the device 10, the locking device 43 is rotated about the first longitudinal axis 22 into the locking position. In the process, locking elements 45 of the locking device 43 engage in the groove region 34 of the shank 14 and lock the shank 14 to the tool fitting 13. The basic position of the locking device 43 is optional and can be omitted; the receiving position and locking position of the locking device 43 are necessary.

[0034] FIGS. 5A-C show the rotary driving part 42 of the tool fitting 13 in a side view (FIG. 5A), in a longitudinal section along the section plane A-A in FIG. 5A (FIG. 5B) and in a plan view of the interface with the shank 14 (FIG. 5C).

[0035] The rotary driving part 42 is sleeve-shaped with a central through-hole 47 and is composed of a plurality of portions, which in the exemplary embodiment are made in one piece. In addition to the internal thread, the rotary driving part 42 comprises an inner conical region 48 and an inner driver region 49. The inner driver region 49 has a plurality of first inner rotary drivers 51 and a plurality of second inner rotary drivers 52. In the connected state of the device 10, the first outer conical region of the shank 14 lies on the inner conical region 48 of the rotary driving part 42, the first inner rotary drivers 51 engage in the first longitudinal grooves 37 and the second inner rotary drivers 52 engage in the second longitudinal grooves 38.

[0036] The first and second inner rotary drivers 51, 52 are combined under the term “inner rotary drivers”. In a plane 53 perpendicular to the first longitudinal axis 22, the first inner rotary drivers 51 have a first width B.sub.1 and a first depth T.sub.1 and the second inner rotary drivers 52 have a second width B.sub.2 and a second depth T.sub.2. Parallel to the first longitudinal axis 22, the first inner rotary drivers 51 extend over a first height H.sub.1 and the second inner rotary drivers 52 extend over a second height H.sub.2. In order to set the surface pressure to be as small as possible, the first height H.sub.1 of the first inner rotary drivers 51 and the second height H.sub.2 of the second inner rotary drivers 52 are as large as possible.

[0037] According to the invention, the first depth T.sub.1 of the first inner rotary drivers 51 is identical to the second depth T.sub.2 of the second inner rotary drivers 52. With the old tool fitting, the second depth of the second inner rotary drivers 52 is smaller than with the new tool fitting. The same depth (T.sub.1=T.sub.2) of the first inner rotary drivers 51 and second inner rotary drivers 52 has the advantage that the new tool fitting cannot be combined with the old shank, since the dimensions of the second longitudinal grooves 38 in the plane perpendicular to the second longitudinal axis 24 of the shank 14 are too small to be combined with the second inner rotary drivers 52.

[0038] In addition, in the exemplary embodiment of the device 10, the first width B.sub.1 of the first inner rotary drivers 51 is identical to the second width B.sub.2 of the second inner rotary drivers 52. The same depth (T.sub.1=T.sub.2) and the same width (B.sub.1=B.sub.2) of the first inner rotary drivers 51 and second inner rotary drivers 52 has the advantage that, when assembling the device 10, there is no need to assign the first inner rotary drivers 51 to the first longitudinal grooves 37 or the second inner rotary drivers 52 to the second longitudinal grooves 38.