Sinker with depth stop

Description

field of technology

[0001] The invention relates to a tool with a shaft which can be driven about a rotational axis and with a tool head which is connected thereto and which operates in rotation and has a working section which extends over an axial distance, wherein a depth limiter which can be fixed on the shaft in various axial positions by means of a radially displaceable restraining element has a stop surface which lies in the axial positions in the working section. State of the art

[0002] DE 879 191 C discloses a clamping head for a twist drill in which locking balls are designed to engage in locking recesses in the twist drill. The locking recesses run along a spiral line, which also includes the rib separating the two adjacent chip channels.

[0003] WO 87 / 00100 describes a countersink designed as a chuck, which has three threaded holes running on a helical thread line, into which a fastening screw can be screwed optionally, which can be supported on a rib of a twist drill separating two chip channels.

[0004] DE 10 2008 022 968 A1 and EP 2 093 001 A1 disclose a countersink in which a depth stop is arranged on a circular-cylindrical section of a shaft. Using a locking element in the form of a grub screw, the depth stop can be secured to the shaft in various axial positions. A stop surface of the depth stop can thus be positioned at any desired location in the working section, allowing the diameter of the countersink produced with the tool head designed as a countersink to be determined by the axial position.

[0005] DE 72 07 706 U discloses a countersink with a depth stop in the form of a sleeve. The shaft has an external thread onto which the sleeve is screwed, allowing the diameter of the countersink to be adjusted by varying the rotational position of the sleeve.

[0006] DE 737 134 describes a drilling tool with a depth stop, whereby the tip of a grub screw engages in the threads of a trapezoidal thread for axial adjustment.

[0007] DE 10 2005 017 872 A1 describes a bit holder with a stop sleeve. The stop sleeve has a slanted slot with recesses. A locking pin protrudes from the shaft and engages the slot. By rotating the sleeve, the screw-in depth of the bit inserted into a receiving opening can be adjusted.

[0008] WO 87 / 00100 A1 describes a countersink that can be attached to a drill shank, whereby grub screws can be screwed into one or more threaded holes arranged on a helical line so that the tips of the grub screws can contact the cylinder surfaces. Summary of the invention

[0009] The invention is based on the object of further developing the generic tool in a way that is advantageous in use.

[0010] First and essentially, it is proposed that a cylindrical section of the shaft has a plurality of positioning recesses arranged on a helical thread line. The positioning recesses can be bores with a rounded base. However, they can also be bores with a funnel-shaped, conical base. However, the bores can also have a flat base. The positioning recesses can have a circular opening edge. However, the opening edge can also deviate from a circular shape. The positioning recesses have an axial spacing corresponding to approximately one millimeter. The diameter of the openings in the bore can be greater than 1 mm. However, it is also provided that the axial spacing of the positioning recesses is greater or less than 1 mm.The axial distance between the centers of the positioning recesses can be less than the diameter of the positioning recesses or less than half the diameter of the positioning recesses. The axial distance between the centers of immediately adjacent positioning recesses is greater than the axial distance and in particular greater than one and a half times the diameter of the positioning recesses. The restraining element has a tip that can selectively engage in one of the several positioning recesses, wherein the tip is preferably self-centeringly supported on a rounded or tapered base. The tip can thus be rounded or formed by a cone or truncated cone. In a preferred embodiment, the restraining element is a grub screw that is screwed radially into a threaded bore of a restraining body.To change the axial position of the depth stop, the restraining element must first be released and then the depth stop must be moved axially and circumferentially. For this purpose, it is advantageous if the depth stop is a sleeve. When the restraining element is released, the depth stop is preferably freely movable relative to the cylinder section both axially and circumferentially. The tool head, which can have a cutting edge or can be formed by a screwing tool head, extends through the sleeve. In a preferred development of the invention, each positioning recess is provided with an associated marking. Such a marking is formed by a symbol, in particular a visual symbol, for example a printed or embossed number. This number can represent the value of an axial position in millimeters or another unit.In a preferred embodiment of the invention, the tool is a countersink. The tool head is a cutting head having a cutting edge. The cutting edge extends obliquely to the rotation axis. It thus has both a radial and an axial directional component. The opening width of the created countersink changes with the immersion depth of the cutting head. The symbol printed on or embossed into the shaft can indicate a value, for example in millimeters, for the diameter of the opening width of the created countersink. The cutting edge of the countersink rotates on a conical surface or a truncated cone surface with a shaft driven about the rotation axis. The tool section preferably has a tip. The tool head can also be designed as a bit holder, drill, conical drill, step drill, or hole cutter. The locking element can be more than just a grub screw.It can also be a screw with a head or a pin with a tip that can be moved radially in some other way, for example against the action of a return spring. The shape of the tip can correspond to the shape of the positioning recess, so that, for example, a rounded tip rests against the conical surface of the positioning recess or a conical or truncated cone-shaped tip section of the restraining element rests flat against a conical section of the positioning recess. Alternatively, a section of the tip of the restraining element can make an annular contact with the bottom of the positioning recess. For example, the bottom of the positioning recess can be conical and the tip of the restraining element can be round. The depth limiter can have a restraining body in which the restraining element is arranged.A sleeve section can be attached to this restraining body, which has the stop surface and can rotate relative to the restraining body. The restraining body can be made of plastic and have axial webs with windows between them. The stop surface can be a closed annular surface all the way around. It is also advantageous if the cylinder section has a magnet arranged at the axial height of the positioning recesses. The restraining body, which supports the restraining element, or the restraining element itself can be made of a ferromagnetic material, so that the restraining body, which can preferably be freely displaced over the cylinder section, is held in the area in which the positioning recess is located by the force of the magnet.The restraining body is pre-positioned in a floating manner on the axial area containing the positioning recesses by a magnet assigned to the cylinder section. It is held elastically in a neutral position from which it can be displaced in both axial directions. From a displaced position, the restraining body can swing back to the neutral position by magnetic force. Short description of the drawings

[0011] Embodiments of the invention are explained below with reference to the accompanying drawings. They show: Fig. 1 an exploded view of a countersink according to the invention, Fig. 2 the countersink with a depth limiter shown in section, Fig. 3 enlarged section III-III in Fig. 2, Fig. 4 a sectional view of a second embodiment, Fig. 5 the second embodiment in section in a perspective view, Fig. 6 a third embodiment in a sectional view, Fig. 7 the third embodiment in a perspective view, Fig. 8 a fourth embodiment in a sectional view, Fig. 9 the fourth embodiment in a perspective sectional view, Fig. 10 a fifth embodiment in a sectional view, and Fig. 11 the fifth embodiment in a sectional perspective view. Description of the embodiments

[0012] The embodiments illustrated in the drawings are countersinks, cone drills, or step drills. The tools essentially consist of two or three parts, respectively. A shaft 1 has an elongated shape. A first end of the shaft 1 forms a drive section 2 with a polygonal cross-section, which can be inserted into a chuck of a drive tool to drive the shaft 1 in rotation about the rotational axis A.

[0013] The drive shaft 2 continues into a cylindrical section 7. On the side opposite the drive shaft 2, a tool head 3 adjoins the cylindrical section 7. The tool head 3 can be connected to the drive shaft 2 as a single material. However, it can also be a separate part that is plug-connected to the drive shaft 2. For example, the tool head 3 can be formed by a screwing tool profile of a bit that is inserted into an insertion opening of the drive shaft 2 or the cylindrical section 7.

[0014] When in the Figures 1 - 3In the first embodiment shown, the tool head 3 is a countersunk head with a cutting edge 4, which in the embodiment extends at an angle of 45° to the axis A. The cutting edge 4 runs in a straight line and thus describes a movement along a conical surface when the tool head 3 rotates about the axis of rotation 4. The angle at which the cutting edge 4 extends to the axis A can, however, also have a different value. In the embodiment, the tool head 3 has a cylindrical outer surface with a window. The window is the opening of a discharge channel that runs diagonally through the tool head 3. The cutting edge 4 is formed by an arcuate peripheral edge, at which the chip discharge opening borders the conical surface of the tool head 3. In the embodiment, the cutting edge 4 thus lies in a conical tip surface of the tool head 3.The tip surface extends from the tip 5 to a section 6 of the tool head 3 with the largest diameter, which extends on a cylinder surface or a slightly undercut cylinder surface.

[0015] Another part of the tool is a depth stop 12, which in the exemplary embodiment is again formed in two parts. An annular restraining body 13 has an annular opening through which the cylindrical section 7 protrudes. A disc-shaped section of the restraining body 13 is adjoined by a neck 17, which forms an annular recess into which a collar 24 of a plastic stop body 20 can engage. A step 18 for axially securing the collar 24 can be formed by a snap ring.

[0016] The collar 24 is a single material component of the stop body 20, which forms a stop surface 21 on its side facing away from the collar 24. The stop surface 21 is annular and extends in a plane perpendicular to the rotational axis A. The tool head 3 has a working section 8. The working section 8 is formed by an axial section into which the cutting edge 4 can create a countersink. The immersion depth of the cutting edge 4 or the tool head 3 into a workpiece can be limited by the axial position of the stop surface 21. In conjunction with this, the opening width of the countersink created with the countersunk head can be adjusted.

[0017] Restraining elements are provided to fix the axial position of the depth stop 12 relative to the tool head 3. The restraining elements according to the invention consist of a plurality of positioning recesses 10 arranged in the cylinder section 7. The positioning recesses 10 are spaced apart from one another both in the circumferential direction of the cylinder section 7 and in the axial direction relative to the axis A. The total number of positioning recesses 10 lies on a helical profile 9, shown as a dashed line.

[0018] The positioning recesses can have a tapered, funnel-shaped, conical, or truncated cone-shaped base. However, the base can also be dome-shaped. A tip 15 is provided, which is fixedly assigned to the restraining body 13. In the exemplary embodiment, the tip is formed by a grub screw 14, the externally threaded shaft of which is screwed into a radial threaded bore 19 of the restraining body 13. The tip can be rounded, for example, a spherical surface section. In the exemplary embodiment, the tip is conical or truncated cone-shaped, and the base of the positioning recess is conical. The cone angle and the angle of the cone are identical, so that the surface of the tip lies flat against the surface of the base of the positioning recess.By engaging a tool at a screw tool engagement opening 16, the grub screw 14 having the tip 15 can be rotated such that the tip 15 is supported in a self-centering manner on the bottom of the positioning recess 10.

[0019] In the exemplary embodiment, the positioning recesses 10 have a circular opening with a diameter D. The adjacent positioning recesses are spaced apart from one another in the circumferential direction such that a cylinder jacket section of the cylinder section 7 extends between the adjacent positioning recesses 10. The width of this space, measured in the circumferential direction, between two adjacent positioning recesses 10 lies approximately between half the diameter of a positioning recess and the diameter of a positioning recess. The axial distance between two adjacent positioning recesses is exactly one millimeter in the exemplary embodiment. With a cutting edge angle of 45° to axis A, this distance then corresponds to a change in the opening diameter of the countersink by one millimeter. With a different cutting edge angle, the axial distance between two adjacent positioning recesses is selected differently.The axial distance between two adjacent positioning recesses 10 is less than the diameter D of a positioning recess or less than the radius of a positioning recess 10.

[0020] On the side of the depth stop 12, and in particular of the restraining body 13, facing away from the restraining body 13, the shaft 1 and in particular the cylinder section 7 have a plurality of characters 11. The characters 11 are numbers and indicate the opening diameter of the countersink created with the countersink when the grub screw 14 engages with its tip 15 in the positioning recess 10 associated with the respective character 11.

[0021] While in the Figures 1 - 3 The embodiment shown shows a tool head 3 with a single cutting edge 4, the one shown in the Figures 4 and 5 The second embodiment shown has a tool head with a plurality of cutting edges 4.

[0022] The Figures 6 and 7The illustrated embodiment is a step drill. The stop surface 21 can be positioned in such a way that a countersink is created. The axial distance between the positioning recesses 10 is somewhat larger than in the Figures 1 - 5 illustrated embodiments. If the tip of the restraining element 14 is fixed in a positioning recess 10, the plane in which the stop surface 21 lies intersects a section of the stepped cutting edge 4 of the tool head 3 extending on a truncated cone surface. A plurality of cylindrical sections of the tool head 3 with different diameters are each connected to one another by truncated cone-shaped sections. The symbol 11 here can indicate the diameter of the largest cylindrical section projecting beyond the stop surface 21, to which the truncated cone section of the tool head 3 intersected by the stop surface 21 adjoins.

[0023] The Figures 8 and 9The embodiment shown is a conical drill bit that works similarly to the one shown in the Figures 1 - 5 Countersink shown. However, the angle of cutting edge 4 to axis A is more acute here.

[0024] The Figures 10 and 11 The embodiment shown essentially corresponds to the one shown in the Figures 6 and 7 illustrated embodiment. Here, however, a shaft of the tool head 3 is inserted into the cylinder section 7 and secured with a grub screw 26.

[0025] This step drill can be used to drill holes with different diameters, whereby the diameters are indicated as symbol 11 on the shaft 1 or the cylinder section 7.

[0026] In some embodiments, the shaft 1, the cylinder section 7 and the tool head 3 are formed from a single body made of the same material. In other embodiments, the shaft 1, the tool head 3 and the cylinder section 7 are individual parts connected to one another. Figures 10 and 11 In the embodiment shown, the tool head 3 can be changed by loosening the grub screw 26.

[0027] In some embodiments, the cylinder section 7 is formed by a sleeve. The drive section 2 is inserted into one opening side of the sleeve. A fastening section of the tool head 3 is inserted into the other opening side of the sleeve. The two sections of the tool head 3, on the one hand, and of the drive shaft 2, on the other hand, inserted into the cylinder section 7 are firmly connected to the cylinder section 7. A magnet 25 is provided, which is arranged within the sleeve-shaped cylinder section 7 between the sections of the tool head 3 and the drive shaft 2 inserted into the cylinder section 7. The magnet is arranged at the axial height of the positioning recesses 10.The restraining element, in the exemplary embodiment the grub screw 14 and / or the restraining body 13 that supports the restraining element, are made of a ferromagnetic material, so that the depth stop 12 is pre-positioned by the magnetic force of the magnet 25 when the restraining element is in the release position. The depth stop 12 is thus pre-fixed by the magnet in a floating position, from which it can be axially displaced against the magnetic restoring force both in the direction of the drive shaft and in the direction of the tool head 3. From an axially displaced position, the unfixed depth stop 12 slides automatically back to the neutral position.

[0028] The above statements serve to explain the inventions covered by the application as a whole, which each independently develop the state of the art by at least the following combinations of features, whereby two, several or all of these combinations of features can also be combined, namely:

[0029] A tool characterized in that the shaft 1 has a plurality of positioning recesses 10 arranged on a helical line 9 and the restraining element has a tip 15 which selectively engages in one of the plurality of positioning recesses 10.

[0030] A tool characterized in that the restraining element is a grub screw 14.

[0031] A tool characterized in that the depth stop 12 is a sleeve.

[0032] A tool which is characterized in that the depth limiter 12 is continuously displaceable on the shaft 1 when the tip 15 does not engage in the positioning recess 10.

[0033] A tool which is characterized in that the axial distance b of the centers of two immediately adjacent positioning recesses 10 is smaller than the diameter D of the positioning recess 10, wherein it is particularly provided that the axial distance b is smaller than the radius of a circular opening edge of the positioning recesses 10.

[0034] A tool which is characterized in that the shaft 1 has a magnet 25 at the axial height of the positioning recesses 10, which magnet interacts magnetically with the restraining element and / or a restraining body 13 carrying the restraining element in such a way that the depth limiter 12 can be displaced on the shaft 1 in both axial directions against a magnetic restoring force.

[0035] A tool which is characterized in that the tool head 3 has a cutting edge 4 having both a radial and an axial directional component in the working section 8 for drilling countersinks into the surface of a workpiece, wherein the positioning recesses 10 are assigned symbols 11 indicating the opening width of the countersinks.

[0036] A tool characterized in that the characters 11 are arranged axially on the side of the associated positioning recess 10 facing away from the tool head 3.

[0037] A tool which is characterized in that the tool head 3 can perform the function of a countersink, a bit holder, a drill, a cone drill, a step drill or a hole cutter and is designed accordingly.

[0038] All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of the application hereby fully incorporates the disclosure content of the associated / attached priority documents (copy of the prior application), also for the purpose of incorporating features of these documents into claims of the present application. The subclaims, even without the features of a referenced claim, characterize independent inventive developments of the prior art with their features, in particular for filing divisional applications based on these claims. The invention specified in each claim may additionally comprise one or more of the features provided in the above description, in particular with reference numerals, and / or specified in the list of reference numerals.The invention also relates to designs in which individual features mentioned in the above description are not implemented, in particular insofar as they are clearly unnecessary for the respective intended use or can be replaced by other technically equivalent means. List of reference symbols

[0039] 1 shaft 2 drive shaft 3 tool head 4 cutting edge A Axis / axis of rotation 5 Great D diameter 6 largest diameter section 7 Cylinder section b axial distance 8 Work section 9 spiral gangline 10 Positioning recess 11 Sign 12 Depth limiter 13 bondage body 14 grub screw 15 Great 16 Screw tool access opening 17 Neck 18 Level 19 threaded hole 20 stop body 21 Stop surface 22 web 23 Window 24 collar 25 magnet 26 grub screw

Claims

1. Tool having a shaft (1) which can be rotationally driven about an axis of rotation (A), a tool head (3) which is connected thereto and operates in rotation and which has a working section (8) extending over an axial distance, wherein a depth limiter (12) can be fixed by a radially fixable restraining element in various axial positions on the shaft (1), wherein the depth limiter (12) comprises a stop surface (21) located in the working section (8) in the axial positions, wherein the shaft (1) comprises a plurality of positioning recesses (10) arranged on a helical path (9) and wherein the restraining element has a tip (15) which selectively engages in one of the plurality of positioning recesses (10), characterised in that the positioning recesses (10) are arranged on a cylindrical section (7) of the shaft (1), the axial distance (b) between the centres of two directly adjacent positioning recesses (10) being less than the diameter (D) of the positioning recess (10).

2. Tool according to claim 1, characterised in that the restraining element is a grub screw (14).

3. Tool according to one of the preceding claims, characterised in that the depth limiter (12) is a sleeve.

4. Tool according to one of the preceding claims, characterised in that the depth limiter (12) is displaceable continuously on the shaft (1) when the tip (15) does not engage in the positioning recess (10).

5. Tool according to claim 1, characterised in that the axial distance (b) is less than the radius of a circular opening edge of the positioning recesses (10).

6. Tool according to one of the preceding claims, characterised in that the shaft (1) has a magnet (25) at the axial height of the positioning recesses (10), which magnetically interacts with the restraining element and / or a restraining body (13) carrying the restraining element in such a way that the depth limiter (12) can be displaced on the shaft (1) in both axial directions against a magnetic restoring force.

7. Tool according to one of the preceding claims, characterised in that the tool head (3) has a cutting edge (4) having both a radial and an axial directional component in the working section (8) for drilling countersinks in the surface of a workpiece, wherein marks (11) indicating the opening width of the countersinks are assigned to the positioning recesses (10).

8. Tool according to claim 7, characterised in that the marks (11) are arranged axially on the side of the associated positioning recess (10) pointing away from the tool head (3).

9. Tool according to one of the preceding claims, characterised in that the tool head (3) can perform the function of a countersink, a bit holder, a drill, a peeling drill, a step drill or a hole cutter and is designed accordingly.