Combined drill and chamfer tool

Abstract

A combined drill and chamfer tool (13, 21) for producing boreholes (29) in a workpiece (28) and for subsequently producing a chamfer (30) on at least one bore edge of the borehole (29), comprising a drill bit (1), which is secured in a rotationally fixed manner in a base body (3), and at least one chamfering blade (4) arranged behind the drill bit (1) in the axial direction, said chamfering blade being mounted in a blade window (25) arranged in the drill shank (35) and spring-loaded so as to be displaceable transversely to the longitudinal axis of the combined tool (13, 21), wherein the drill body (13) comprising the drill bit (1) and the drill shank (35) is made of a solid hard metal material, and wherein a spring-loaded, displaceable control bolt (5) is located in a central longitudinal bore (36) of the solid hard metal drill, the front tip (15) of said bolt controlling the transverse displacement of the chamfering blade (4), which is transversely displaceable within the blade window (25).

Claims

1. A combined drill and chamfer tool for producing boreholes in a workpiece and for subsequently producing a chamfer on at least one bore edge of the borehole, comprising a drill bit, a drill shank, and at least one chamfering blade arranged behind the drill bit in the axial direction, said chamfering blade being mounted in a blade window arranged in the drill shank and spring-loaded so as to be displaceable transversely to the longitudinal axis of the combined tool, wherein a drill body comprising the drill bit and the drill shank is made of a solid hard metal material, and in that a spring-loaded, displaceable control bolt is located in a central longitudinal bore of the solid hard metal drill body, a front tip of said bolt controlling the transverse displacement of the chamfering blade, which is transversely displaceable within the blade window, and wherein an adapter sleeve, a diameter of which is equal to or smaller than that of the drill shank, is fastened onto a rear part of the drill shank, with a spring of the spring-loaded displaceable control bolt being arranged in the adapter sleeve.

2. The combined drill and chamfer tool according to claim 1, wherein a fitting length, defined as an axial distance between an end of a drill helix and a beginning of the blade window, ranges from about 0.001 mm to about 2 mm.

3. The combined drill and chamfer tool according to claim 1, wherein a diameter of the drill bit is less than or equal to about 5 mm.

4. The combined drill and chamfer tool according to claim 1, wherein the chamfering blade is embodied as cutting on one side or on two sides.

5. The combined drill and chamfer tool according to claim 1, wherein the chamfering blade has a conically tapering lead-in profiled part which can be broken off.

6. The combined drill and chamfer tool according to claim 1 wherein the adapter sleeve is pressed directly onto the drill shank, and wherein the spring is a compression spring, and the compression spring and an adjustment screw for the compression spring are arranged within the adapter sleeve.

7. The combined drill and chamfer tool according to claim 1 wherein the adapter sleeve has the same diameter as the drill shank.

8. The combined drill and chamfer tool according to claim 1 wherein the diameter of the adapter sleeve is smaller than the diameter of the drill shank by about 0.05 mm to about 0.2 mm.

9. The combined drill and chamfer tool according to claim 1, the tool being adapted to be clamped in a chuck having clamping surfaces, the tool being further adapted such that the clamping surfaces of the chuck reach beyond the length of the drill shank and extend up to the area of the adapter sleeve.

10. The combined drill and chamfer tool according to claim 9 wherein the drill shank is adapted to be clamped in the chuck but the adapter sleeve is adapted to not be clamped in the chuck.

Description

(1) The drawings show:

(2) FIG. 1: a perspective representation of a combined drill and chamfer tool according to the prior art

(3) FIG. 2: a sectional view of the combined drill and chamfer tool according to the prior art

(4) FIG. 3: a perspective representation of the novel combined drill and chamfer tool according to the invention

(5) FIG. 4: a sectional view of the assembly of FIG. 3

(6) FIG. 5: a perspective view of the chamfering blade

(7) FIG. 6: a detailed representation of the drill body, inserted into the base body

(8) FIG. 7: a representation similar to FIG. 6 showing additional details during the drilling process and during the deburring process

(9) FIG. 8: a modified embodiment of a combined drill and chamfer tool

(10) Document WO 2005/037473 A1 corresponds in principle to the prior art as described in FIGS. 1 to 2 of the present application, since said document specifies that the blade window with the deburring blade transversely displaceable therein is disposed in the soft part of the drill shank, which is associated with the above-described disadvantages.

(11) Therefore, WO 2005/037473 A1 discloses only one variant of the prior art according to FIGS. 1 and 2, described in the following.

(12) FIGS. 1 and 2 show a conventional combined drill and chamfer tool according to the prior art, in which a central longitudinal bore is disposed in a base body 3, into which a compression spring 6 is inserted. Compression spring 6 is pushed forward by means of a spacer bolt 7 and a tightening bolt 8 situated rearward thereof, and is pressed against a cylindrical attachment 14, which is preferably integrally connected to a control bolt 5. Control bolt 5 thus engages at its front tip 15 into an assigned control groove 16 of a chamfering blade 4, which is therefore arranged spring-loaded in the transverse direction so as to be transversely displaceable in a blade window 25.

(13) In the embodiment example according to the prior art shown, chamfering blade 4 is designed to cut in the forward and the reverse direction. It thus has a cutting edge 17 that faces the forward direction and a cutting edge 18 that faces the reverse direction.

(14) What is important here is that, beyond blade window 25, an additional cylindrical attachment is provided in base body 3 in the prior art according to FIGS. 1 and 2, because a mounting bore must be provided in this forward region, into which a threaded extension 32 of a drill bit 1 can engage. Threaded extension 32 is provided with a receiving thread 2, which is used for screwing drill bit 1 into base body 3.

(15) Drill helix 34 of drill bit 1 therefore ends before the mounting bore into which threaded extension 32 is screwed. This results in the disadvantage that an awkward fitting length 31 that would ideally be avoided is formed between the rear end of drill helix 34 and the front end of blade window 25.

(16) It is an object of the invention to eliminate or at least substantially minimize this fitting length 31.

(17) The critical step in achieving this object will be described in reference to a combined drill and chamfer tool 21, which is illustrated in detail in the subsequent FIGS. 3 to 8.

(18) According to the invention, drill bit 1 according to FIG. 6 is integrally connected to a drill shank 35 in an embodiment of a solid hard metal drill such that a continuous drill body 13 is formed, at the front end of which a blade window 25 is located, in which chamfering blade 4 is displaceably mounted.

(19) In drill shank 35, a central longitudinal bore is located, into which control bolt 5 extends, with control bolt 5 being capped off at the rear by attachment 14, to which it is connected; according to the representation of FIG. 4, attachment 14 then extends into a base body 3, embodied as shortened, where it is spring-loaded by known compression spring 6.

(20) Thus for the first time, a drill made of solid hard metal and having a forward drill bit 1 and a drill shank 35 is now described, wherein transversely extending blade window 25 is arranged in the region of drill shank 35, thereby eliminating fitting length 31 because according to the invention, the chamfering blade is now located within drill shank 35 itself.

(21) Thus it is now possible for the first time to produce drill bit 1 in drill shank 35 from the same material, so that blade window 25 and chamfering blade 4 inserted therein are embodied as especially resistant to chip impacts and as flexurally stable.

(22) Due to the shortened lengthelimination of fitting length 31blade window 25 is now situated immediately adjacent to drill helix 34 in the axial direction, as is illustrated mostly clearly in FIG. 6.

(23) The entire drill body 13 is inserted into a mounting bore 12 in a sleeve-type base body 3 according to FIG. 4, and can be secured in mounting bore 12 in any desired manner. Drill shank 35 of drill body 13 can be secured there by screwing, snap-locking, shrink-fitting, pressing or by other methods, with an interlocking connection that is capable of withstanding heavy loads being particularly preferred.

(24) It is an additional feature of the invention that now the chamfering blade is designed to cut on only one side, specifically with a rear cutting edge 18, although the invention is not limited to this. FIGS. 3 to 7 show such a single-edged chamfering blade 4 merely as a possible embodiment example.

(25) It is also possible for a double-edged chamfering blade to be used, as shown in FIGS. 1 and 2. Rather than providing a single cutting edge 18 that cuts toward the rear, a cutting edge 17 that cuts forward may thus also be provided in the embodiment example according to FIGS. 3 to 7.

(26) A further feature of the invention is the simple mounting of chamfering blade 4, which is particularly advantageous for deburring small diameters. As is clear from FIG. 6, the chamfering blade according to FIG. 5 has a conically tapering lead-in profiled part 9, and the chamfering blade as a whole is inserted in the direction of arrow 24 into blade window 25 at the bottom according to FIG. 6, with lead-in chamfer 10 being supported against tip 15 of control bolt 5, which projects, spring-loaded, into blade window 25, and sliding therealong, specifically until tip 15 reaches the region of control groove 16 of chamfering blade 4, where it snaps into place.

(27) As soon as this mounting position according to FIG. 6 has been reached, lead-in profiled part 9 can be broken off. Thus it also serves as a handle for use in installing chamfering blade 4.

(28) For this purpose, lead-in profiled part 9 is embodied as weakened in the transverse cross-section by two mutually opposing transverse grooves 22, 23 where a breaking web 20 is formed, so that when lead-in profiled part 9 is bent around breaking web 20, breaking web 20 breaks, placing the blade in its final working position according to FIG. 7.

(29) FIG. 5 also shows that a chip deflector 19 is provided in a known manner on cutting edge 18.

(30) FIG. 7 shows combined drill and chamfer tool 21 according to the invention in a working position.

(31) In this drawing, the drill with its drill bit 1 has already produced a workpiece bore 29 in a workpiece 28, and has already been passed through said workpiece bore 29. This passage has been carried out in the direction of arrow 26.

(32) Combined drill and chamfer tool 21 as a whole is then retracted in the direction of arrow 27, so that the rear end of chamfering blade 4 rests with its cutting edge 18 against the front bore edge, where it produces an angled chamfer 30.

(33) As is also clear, the front side of chamfering blade 4 also has a lead-in chamfer 33, which ensures that when the drill with its drill bit 1 enters workpiece bore 29, chamfering blade 4 will be pushed back into the interior profile of blade window 25 and will not exert any cutting action in the region of workpiece bore 29.

(34) In any case, what is important is that blade window 25 along with the chamfering blade, which is spring-loaded here so as to be displaceable in a transverse direction, is disposed in the drill, which is made of a continuous solid hard metal.

(35) As a result, it is now possible for the first time to produce the drill as an integrated part together with the chamfering blade, and to later secure it in a softer, sleeve-shaped base body suitable for this purpose.

(36) The invention also provides for a plurality of chamfering blades 4 (more than one) to be arranged in a blade window 25 orin another variantfor a second and optionally a third blade window to be provided at an axial distance from the one blade window 25, with a chamfering blade being arranged in each additional window. Each of the chamfering blades can be mounted and controlled by the common control bolt 5 so as to be transversely displaceable in its assigned blade window. In another embodiment, each chamfering blade can be assigned its own control bolt 5, spring-loaded in the axial direction.

(37) As is clear from FIG. 6, control bolt 5 is arranged spring-loaded and axially displaceably in longitudinal bore 36 of drill body 13.

(38) FIG. 8 shows a modified embodiment example in which an adapter sleeve 38, the outer diameter 41 of which corresponds to outer diameter 41 of drill shank 35, is connected in a rotationally fixed manner in the region of a connection 39 to the rear end face of drill shank 35.

(39) The actuating means for the displacement of control bolt 5 is disposed in adapter sleeve 38. Control bolt 5 is extended toward the rear by a head piece 37 of enlarged diameter, with head piece 37 extending into a center bore of adapter sleeve 38. One end of compression spring 6 is supported against head piece 37, while the other end is supported against tightening bolt 8, which is screwed into a threaded bore at the rear end of adapter sleeve 38.

(40) Since outer diameter 41 of drill shank 35 is preferably identical to outer diameter 41 of adapter sleeve 38, it is now possible to clamp drill shank 35, which is made of a solid hard metal material, directly into chuck 40 of a drive machine. Base body 3 is thus eliminated, and the drive torque can be transmitted from chuck 40 directly to drill shank 35.

LIST OF REFERENCE SYMBOLS

(41) 1 drill bit 2 receiving thread 3 base body 4 chamfering blade 5 control bolt 6 compression spring 7 spacer bolt 8 tightening bolt 9 lead-in profiled part 10 lead-in chamfer 11 combined drill and chamfer tool 12 mounting bore 13 drill body 14 attachment (of 5) 15 tip (of 5) 16 control groove 17 cutting edge (forward) 18 cutting edge (rearward) 19 chip deflector 20 breaking web 21 combined drill and chamfer tool 22 transverse groove (top) 23 transverse groove (bottom) 24 arrow direction 25 blade window 26 arrow direction 27 arrow direction 28 workpiece 29 workpiece bore 30 chamfer 31 fitting length 32 threaded extension 33 lead-in chamfer 34 drill helix 35 drill shank 36 longitudinal bore 37 head piece 38 adapter sleeve 39 connection 40 chuck 41 outer diameter