AU599862B2

AU599862B2 - Drilling device

Info

Publication number: AU599862B2
Application number: AU41664/89A
Authority: AU
Inventors: Artur Prof. Dr. H.C. Fischer
Original assignee: Fischerwerke Artur Fischer GmbH and Co KG
Current assignee: Fischerwerke Artur Fischer GmbH and Co KG
Priority date: 1988-10-14
Filing date: 1989-09-25
Publication date: 1990-07-26
Anticipated expiration: 2009-09-25
Also published as: DE58901943D1; CA2000054A1; HU895257D0; EP0363617A1; PT91970A; HU206651B; RU1829988C; CS277058B6; BR8905212A; NO894100L; KR900006050A; ES2034536T3; NO894100D0; PT91970B; DE3903369A1; HUT54554A; FI894582A; CA2000054C; CS579989A3; EP0363617B1

Description

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or8m1 Form

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl Application Number: Lodged: Complete Specification Lodged: Accepted: Lapsed: Published: Priority:

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Related Art: Name of Applicant: Address of Applicant: Actu l Inventors: TO BE COMPLETED BY APPLICANT fischerwerke Artur Fischer GmbH Co. KG Weinhalde 14-18, D-7244 Waldachtal 3/Tumlingen, Federal Republic of Germany.

Dr. h.c. Artur Fischer Address for Service: CALLINANS, Patent Attorneys, of 48 Bridge Road, Richmond, 3121, Victoria, Australia.

Caoplete Specification for the invention entitled: "DRILLING DEVICE' ThM following statement is a full description of this invention, including the best method of performing it known to me:- Drilling Device for Producing Drill Holes with an Undercut The invention relates to a drilling device for producing drill holes with an undercut.

German Offenlegungsschrift 33 40 090 discloses a drilling device in which a drill bit can be screwed into a drill bit holder. In the region of the drill bit holder there is provided a suction bell which surrounds the drill bit holder and the drill shank. The suction bell is attached by o1,09 way of a suction hose to a suction fan of a drilling machinie o or similar apparatus. The purpose of the suction device is to suck away the d7rilling dust accumulating in the drill hole during the drilling operation. With this known device, the drill shank is guided with lateral play in a suction sleeve so that the drill bit is pivotable within the suction sleeve.

Through the pivoting movement it is possible to produce a widened part of the bottcm of the drill hole, generally referred to as an undercut.

Metal expansible fixing plugs can be inserted in a E.o0, drill hole with an undercut; these expand in the region of the 0 I S, undercut and can thus be anchored positively in the drill hole.

In order to be able to produce an undercut at the bottom of the drill hole that is as accurate as possible, the pivoting movement of the drill bit has to be limited; this can be achieved in that approximately in the middle of the drill 2

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shank the drill bit has a cross-sectional enlargement which serves as a pivot bearing that engages the wall of the drill hole. The cross-sectional enlargement, however, makes it difficult to suction off drilling dust, since there is only a small gap left clear in the region of the cross-sectional enlargement for sucking dust away.

The invention is based on the problem of providing a s drilling device for producing drill holes with an undercut, and with a suction device which is of simple construction and 0o0i0° allows drilling dust to be sucked away at the drill bit tip.

To overcome this problem the present invention o co provides a drilling device for producing drill holes with an undercut, said device including a drill bit holder, a drill eoo bit attachable to the drill bit holder, and a suction bell surrounding the drill bit holder, wherein the drill bit has a drill head with a laterally projecting drill plate, said drill *00# Sshank in its middle region having a cross-sectional 4 4 t 1 enlargement, said drill shank having a continuous axial bore i which opens into a suction chamber of the drill bit holder, said suction chamber being open towards the suction bell V surrounding it, and in the region of the cross-sectional

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enlargement there are arranged indentations on the otherwise Ssmooth drill shank.

The continuous axial bore enables the drilling dust to be sucked away directly at the drill bit tip, the indentations provided in the region of the cross-sectional enlargement of the drill bit allowing the volume of air sucked 3 away to flow back. The indentations additionally have the i advantage that the drill shank is not able to jam in the drill i hole. When the drilling device is constructed with a smooth drill shank and a drill shank enlargement which corresponds approximately to the diameter of the drill head, the drill bit frequently jams, as test drillings have shown.

The drill bit is preferably screwed by means of a threaded portion into the drill bit holder which forms a suction chamber and is surrounded by a tubular suction bell.

44 .0 The suction bell preferably consists of a portion of tube with a laterally projecting suction nozzle to which a suction hose of a suction pump can be attached in a manner known per se.

The tube portion of the suction bell is held in a very simple manner between two flanges, the one flange being constructed on the drill bit holder and the other flange being constructed on the drill shank. The flange constructed on the drill shank serves at the same time as a depth step determining the maximum depth of the drill hole.

The indentations formed on the drill shank, which are about 1 to 2 cm long, preferably have a pitch such that they convey the drilling dust accumulating in this region towards the drill head. The pitch of the indentations may alternatively, however, be such that the indentations alternate oppositely to each other or are of the same construction, as in the case of drilling dust grooves, if this appears suitable for special cases of application. The indentations serve both as air inlet channels and also for A further transport of the drilling dust acuuulating in this region.

So that the drill plate in the drill head can be mounted in an optimum manner, it is advantageous to guide the continuous bore laterally past the drill plate at a distance therefrom. The drill plate can thus be inserted in a groove provided in the solid part of the drill head.

It is especially advantageous to branch the continuous bore in the region of the drill head, so that on W,0 each side of the drill plate a channel of the continuous bore leads to a suction opening. This can also be regarded as a forking of the continuous bore. The two suction openings

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resulting therefrom allow the accumulating drilling dust to be 444 t#4 sucked away directly on both sides of the drill plate.

The invention is explained in detail hereinafter with reference to the drawing, in which Figure 1 shows a preferred non-limitative embodiment of a three-part drilling device according to the invention; Figure 2 shows a cross-section of the drill bit holder of the drilling device according to Figure 1; and Figure 3 shows the front part of the drill bit with a branched or forked continuous bore (side view and front end :i view).

The drilling device illustrated in Figure 1 consists of a drill bit holder 1, a drill bit 2 and a suction bell 3.

The drill bit holder 1 has a fixing shank 4, by which it can be clamped in a drill chuck or similar part of a drilling 5 machine. In addition, the drill bit holder 1 has a suction chamber 5 onto which the drill bell 3 can be pushed from below. An opening 6 connects the suction chamber 5 to the inner chamber 7 of the suction bell 3.

At the lower end of the drill bit holder 1 in a bore 8 forming the suction chamber there is an internal thread 9.

Figure 2 illustrates the arrangement of the bore 8.

The drill bit 2 can be screwed into the internal thread 9 using a threaded portion 10. Prior to this, however, 11Z the suction bell 3 is pushed over the suction chamber 5. A 0 on o flange 11 formed on the drill bit holder 1 and a flange 12 formed on the drill bit 2 close off the suction bell 3 at its S two end faces.

0 0 °The drill bit 2 has a smooth shank 13 which is provided with indentations 14 distributed around its periphery. The indentations 14 are located in the region where the cross-section of the shank is greatest, and serve as external air channels and as reaming elements which prevent the drill bit becoming jammed in the drill hole. The indentations 14 could also be arranged inclined at an acute angle with respect to the longitudinal axis and have a pitch corresponding to the pitch of drilling dust groove. The grooves 14 can, however, also be provided with a pitch such that the drilling dust accumulating in this region is conveyed in the direction of the drill head The drill bit 2 has a continuous axial bore 16 which is represented in the drawing by broken lines. The continuous 6 i ~LI i-l C--ii bore 16 has its smallest diameter in the region of the drill head 15, and in the adjoining region where the diameter of the shank is smallest. In the region where the cross-section of the shank is widened, the continuous bore 16 is likewise constructed with a larger diameter, whereby a considerable improvement in the suctioning off of the drilling dust is achieved. The suction chamber 5 is of an even further enlarged diameter and is open towards the suction bell 3 by way of large opening 6. For the suctioning devices there is therefore a flow cross-section that increases continuously from the drill head tip, which assists an optimum suctioning off of the drilling dust.

The suction bell 3 has a laterally projecting 4 4 0 0 suction nozzle 17 to which a suction hose, not illustrated here, of a suction pump can be attached in a manner known per se.

It should also be noted that the cutting edges 18, 19 of the drill plate 20 that project laterally from the drill head 15 serve to produce the undercut in a drill hole. The maximum drill head diameter is therefore determined by the lateral cutting edges 18, 19 and is only slightly larger than the maximum cross-sectional enlargement in the region 21 of the drill shank. The cross-sectional enlargement of the drill shank serves as a pivot bearing, which allows a defined excursion of the drill head 15 at the bottom of the drill hole. The widened region 21 lies against the drill hole wall in this operation.

7 r, -C Figure 3 shows the drill bit 2 in the region of the I drill head 15. The continuous bore 16 forks and leads to i suction openings 22, which are formed on both sides of the drill plate 20 at the front end of the drill head 15. For this purpose, inside the drill head 15 there may be formed straight channels 23 which converge in the drill shank.

In Figure 3 the drill head 15 is flared conically, but it is also possible to construct the drill head as a straight shank part, as shown in Figure 1. In the case of the ii0 conically flared drill head, it is possible, however, to provide larger suction openings 22 than in a drill head of smaller diameter.

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Claims

1. A drilling device for producing drill holes with an undercut, said device including a drill bit holder, a drill bit attachable to the drill bit holder, and suction bell surrounding the drill bit holder, wherein the drill bit has a drill head with a laterally projecting drill plate, said drill shank in its middle region having a cross-sectional enlargement, said drill shank having a continuous axial bore which opens into a suction chaiher of the drill bit holder, 00#4 said suction chamber being open towards the suction bell surrounding it, and in the region of the cross-sectional enlargement there are arranged indentations on the otherwise 61 (1 smooth drill shank.

2. The drilling device according to claim 1, wherein Ssaid indentations extend at an acute angle to the longitudinal axis of the drill bit.

3. The drilling device according to claim 2, wherein the pitch of the indentations is such that they transport drilling dust in the direction of the drill head on rotation A of the drill bit.

4. The drilling device according to any one of the preceding claims, wherein said suction bell is a portion of a tube with a laterally projecting suction nozzle, which tube portion is mounted between respective flanges constructed on the drill bit holder and on the drill shank.

The drill device according to any one of the preceding claims, wherein the continuous bore passes frnm a 9 L small diameter in the region of the drill bit tip to a larger diameter inside the drill shank.

6. The drilling device according to any one of the preceding claims, wherein on the end of the drill bit remote from the drill head there is a threaded portion which is screwed into the drill bit holder.

7. The drilling device according to any one of the preceding claims, wherein the continuous bore is guided laterally past the drill plate.

8. The drilling device according to any one of the oo preceding claims, wherein the continuous bore forks in the region of the drill head and leads to suction openings on both S sides of the drill plate.

9. A drilling device ,ubstantially as hereinbefore described with reference to the accompanying drawings. D A T E D this 25th September, 1989. 4 FISCHERWERKE ARTUR FISCHER GMBH CO KG. By its Patent Attorneys: CALLINANS ~I I 1 I W\\W( 10