AU2003201352A1

AU2003201352A1 - Tool for a hand-held power tool

Info

Publication number: AU2003201352A1
Application number: AU2003201352A
Authority: AU
Inventors: Heinrich Kersten; Frank Schubert
Original assignee: Heller Dinklage Geb GmbH; Gebrueder Heller Dinklage GmbH
Current assignee: Illinois Tool Works Inc
Priority date: 2002-03-19
Filing date: 2003-03-18
Publication date: 2003-10-16
Anticipated expiration: 2023-03-18
Also published as: AU2003201352B2; ATE299419T1; ES2244847T3; DE20204416U1; EP1346800A1; DE50300744D1; EP1346800B1

Abstract

The tool has a circular cross section tool shaft (1) with a work end and a mounting end (2) for mounting in a tool receiver on the handtool machine. On the mounting end is an axial regulator (3) and 3 rotatable bit receivers (4, 5, 6) on the circumference and regularly spaced. The axial regulator runs, axially, to the end of the tool shaft in a sealed grip in the shaft whilst the 3 rotatable bit receivers run axially to the end of the shaft in an open trapezoid groove in the shaft. The radius of the axial regulator's grip may be between two-thirds and three-quarters that of the radius of the tool shaft. The neighbouring flanks (7) of the neighbouring rotatable bit receivers may run parallel to one another. The tool shaft may have a diameter of approximately 10 millimetres.

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: GEBRUDER HELLER DINKLAGE GmbH Actual Inventors: HEINRICH KERSTEN, FRANK SCHUBERT Address for Service: CALLINAN LAWRIE, 711 High Street, Kew, Victoria 3101, Australia Invention Title: TOOL FOR A HAND-HELD POWER TOOL The following statement is a full description of this invention, including the best method of performing it known to us:- 18/03/03,mc13246.cs,1 TOOL FOR A HAND-HELD POWER TOOL The invention concerns a tool for a hand-held power tool with percussing and/or drilling function.

Attempts to optimise the interaction of exchangeable tools with hand-held power tools with percussing and/or drilling function, i.e. drills, percussion drills, drill hammers and other equipment having similar functions have been made for decades. At the same time a tool, and a corresponding tool holder on the hand-held power tool, wherein the tool shank has two diametrally opposite situated driving grooves that are open towards the end as well as two, closed at both ends, axial lockings that are diametrally opposed to one another and at right angle to the driving grooves, have been known for decades.

Consequently, the tool holder of the power tool has two fillet-shaped drivers that engage the driving grooves and two radially displaceable locking bodies, in particular in the form of locking rollers, interacting with the axial lockings. While the drivers engaging the driving grooves serve the purpose of transferring the torque from the hand-held power tool to the tool, the rollers engaging the axial lockings, closed at their ends on the tool shank, serve the purpose of axial securing of the tool in the tool holder.

As far as stress is concerned, the axial locking is not subjected to great requirements. In contrast to this, considerable forces act on the driver of the tool holder due to the torque to be transferred. On the one hand too weakly dimensioned drivers are not in the position to transfer torques of considerable magnitude, on the other hand due to the larger driving grooves necessary for this drivers with large dimensions lead to such a weakening of the tool shank that breakages may occur.

In view of the fact that obviously no optimal compromise could be achieved with the previously known symmetrical construction of diametrically opposed driving grooves and axial lockings having the same dimensions, a plurality of other designs have been suggested for the design of the tool shank of such tools.

The impetus to change the tool shank of the tool or the tool holder of the hand-held power tool is, however, not only technically driven. From the sales point of view it has to be added, that each manufacturer of hand-held tools would like to have his own tool shank with a special design to ensure that the expensive wearing parts, namely the tools which fit his hand-held power tools, are purchased from him. At the same time constant care has to be taken that the driving grooves on the tool and the corresponding drivers on the tool 18/03/03,mci 3246.speci,2 -3holder of the hand-held power tool are, as far as possible, evenly stressed to achieve an optimum transfer of the torque.

Efforts have been made all the time to design a tool that is universally suitable for hand-held tools of various manufacturers and consequently for differently designed tool holders. So far these attempts did not lead to a convincing result.

A starting point for this present design is a tool for a hand-held power tool with percussion and/or drilling function (EP 0 739 267 B1), in which one axial locking and three driving grooves are essentially evenly distributed on the circumference of the tool shank. The driving groove situated opposite the axial locking is, however, wider, so that a locking roller can also engage this driving groove. This driving groove can be used simultaneously as an axial locking. Therefore the tool shank of this tool is compatible also with tool holders, known per se, for which the driving and axial locking is accomplished by two cylindrical diametrically opposite situated locking rollers. However, this step does not alter the basic design of the tool shank as far as an as even as possible driving of the flanks transferring the torque is concerned.

The problem on which the teaching is based, namely to specify a tool for a handheld power tool with percussion and/or drilling functions, that has an as universal application as possible in the tool holders of various designs for hand-held tools of different manufacturers yet ensures a long service life both of the tool and, especially, of the tool holder of the hand-held power tool.

According to the present invention there is provided a tool for a hand-held power tool with percussing and/or drilling function with a tool shank having a circular crosssection with a working end and with an insertion end to insert it into a tool holder of the hand-held power tool, wherein on the insertion end one axial lock and three driving grooves are substantially evenly distributed on the circumference of the tool shank, the axial lock is executed as an axially extending trough, closed towards the end of the tool shank and the driving grooves are executed as axially extending, approximately trapezoidshaped grooves in the tool shank, open towards the end of the tool shank, wherein three driving grooves are symmetrical about the respective radial centreline, that the three driving grooves have on the circumference of the tool shank basically the same width as the axial lock and that at their respective centre the three driving grooves are radially at least as deep, preferably slightly deeper, than the axial lock.. In essence, the symmetrical construction of the three driving grooves and the matching of the external dimensions of the three driving grooves to suit the axial locking. The invention acknowledges that for the 18/03/03.mcl 3246.speci,3 -4axial locking of the tool in the tool holder only one axial locking is required. A locking roller provided possibly opposing it on the tool holder may remain without any function. It merely has to be so arranged in a driving groove situated in this position on the tool shank that no jammings would occur.

The result of the same width of the two other driving grooves, once again situated opposite one another, and the matching of the width of the axial locking is that many tool holders of hand-held power tools available on the market are compatible with this tool shank. In fact, the drivers of the tool holder of the hand-held power tool are always in that section which is covered by the driving grooves in this region. Depending on the tool holder of the hand-held power tool the torque-transmitting flank of one or the other driving groove, sometimes also of two driving grooves, is responsible for the transfer of the torque to the tool. In a surprising manner it has been found that this torque transfer is adequate even under high loads and with powerful hand-held power tools.

The invention is described in detail in the following based on a drawing illustrating only a preferred embodiment. They show in: Fig. 1 a view of the insertion end of the tool shank of a tool according to the invention, and Fig.2 a cross-section according to II-n of Fig. 1.

Fig. 1 shows a tool for a hand-held power tool with percussing and/or drilling function, therefore particularly for a power drill, a percussion/drilling drill, a hammer drill and a similarly operating percussing equipment. This tool has a tool shank 1 with a circular cross-section with a working end having a cutting tip and conveying helix (not illustrated in Fig. and an insertion end 2, shown in Fig. 1, to insert it into a tool holder of the hand-held power tool. The insertion end 2 of the tool shank 1 ensures first of all the axial locking of the tool in the tool holder, so that in the locked position the tool cannot fall out from the tool holder of the hand-held tool, furthermore and in particular, the transfer of the torque from the hand-held tool to the tool during the machining of a workpiece.

On the insertion end 2 of the tool shaft 1 there is first of all an axial lock 3. As Fig.2 shows, in addition, a group of three driving grooves 4, 5, 6 are provided on the insertion end 2. The axial lock 3 and the driving grooves 4, 5, 6 are essentially evenly distributed on the circumference of the tool shank 1.

The axial lock 3 is executed as an axially extending, circular segment-shaped trough, closed towards the end of the tool shank 1. The driving grooves 4, 5, 6 are axially extending, approximately trapezoid-shaped grooves, open towards the end of the tool 18/03/03,mel 3246.speci,4 shank. As it can be clearly seen from Fig.2, all three driving grooves 4, 5, 6 are symmetrical about the respective radial centreline. At the same time the three driving grooves 4, 5, 6 have on the circumference of the tool shank 1 basically the same width as the axial lock 3. At their respective centre the three driving grooves 4, 5, 6 are at least as deep as the axial lock 3. The illustrated and preferred embodiment shows another preferred execution, according to which the depth of the three driving grooves 4, 5, 6 is slightly greater than the depth of the axial lock 3.

Further observing Fig.2 one can see that in this case according to a preferred execution the trough forming the circular segment of the axial lock 3 has a radius that is approx. 2/3 to 3/4 of the radius of the tool shank 1. Consequently the depth of the axial lock 3 is approx. 40% to 50% of the radius of the tool shank 1. By virtue of this the appropriate depth of protrusion of a locking roller in the tool shank 1 is described.

Fig.2 further shows a preferred design, according to which the adjacent flanks 7 of adjacent driving grooves 4, 5; 5, 6 are parallel to one another. By virtue of this an optimisation of the driving groove fillets remaining between the driving grooves 4, 5, 6 and the axial lock 3 is achieved.

It is further provided that both flanks 7 of the trapezoid-shaped driving grooves 4, 6 are situated on radii of a circular sector, the centre 8 of which is situated between the bottom 9 of the driving groove 4, 5, 6 and the centre 10 of the tool shank 1.

The circular sector formed by the respective driving groove 4; 5; 6 may have different widths. The embodiment illustrated shows that in this case an angle of approx.

900 (central angle to centre 8) is included.

Preferably at the same time the centre 8 of the circular sector is situated at approx.

1/4 of the radius of the tool shank 1, measured radially outward from the centre 10 of the tool shank 1.

Finally, the illustrated and preferred embodiment has a construction that is characterised in that when viewed in a circumferential direction the front flank 7 of a driving groove 4; 5 is aligned with the rear flank 7 of the following driving groove 5; 6.

Consequently both flanks 7; 7 of both driving grooves 4; 5 and 5; 6 are in a plane that is situated parallel to a plane including the longitudinal axis of the tool shank 1.

The illustrated and preferred embodiment of a tool can be appropriately used for tool shanks with small diameter, preferably for tool shank diameters of approx. 10 mm. In the illustrated embodiment the depth of the driving grooves 4; 5; 6 would be then approx.

2.4 mm to 2.5 mm.

18/03/03,mcl 3246.speci,S -6- In order to prevent the breaking off of the protruding fillets forming the flanks 7 of the driving grooves 4, 5, 6 of the tool shank 1 in the case of a possible asymmetrical or unilateral load, a construction of the tool according to the invention is recommended that is characterised in that at least in the region of the insertion end, in particular in the region of the flanks 7 of the driving grooves 4, 5, 6 the metal material of the tool has a tough composition and/or is set tough. At most such a fillet will be bent, rendering the tool unusable. However, the material of the fillet does not break off, because it is tough and its composition is not brittle or set brittle. The tool holder on the hand-held power tool remains undamaged.

Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification, they are to be interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof 18/03/03,mcl 3246.speci,6

Claims

1. A tool for a hand-held power tool with percussing and/or drilling function with a tool shank having a circular cross-section with a working end and with an insertion end to insert it into a tool holder of the hand-held power tool, wherein on the insertion end one axial lock and three driving grooves are substantially evenly distributed on the circumference of the tool shank, the axial lock is executed as an axially extending trough, closed towards the end of the tool shank and the driving grooves are executed as axially extending, approximately trapezoid-shaped grooves in the tool shank, open towards the end of the tool shank, wherein three driving grooves are symmetrical about the respective radial centreline, that the three driving grooves have on the circumference of the tool shank basically the same width as the axial lock and that at their respective centre the three driving grooves are radially at least as deep, preferably slightly deeper, than the axial lock.

2. A tool according to Claim 1, wherein the trough forming the circular segment of the axial lock has a radius that is about 2/3 to 3/4 of the radius of the tool shank.

3. A tool according to Claim 1 or 2, wherein the depth of the axial lock is about 40% to 50% of the radius of the tool shank.

4. A tool according to any one of Claims 1 to 3, wherein the adjacent flanks of adjacent driving grooves are parallel to one another.

5. A tool according to any one of Claims 1 to 4, wherein both flanks of the trapezoid-shaped driving grooves are situated on radii of a circular sector, the centre of which is situated between the bottom of the driving groove and the centre of the tool shank.

6. A tool according to Claim 5, wherein the circular sector formed by the respective driving groove includes an angle of about 90'

7. A tool according to Claim 5 or 6, wherein the centre of the circular sector is situated at about 1/4 of the radius of the tool shank.

8. A tool according to any one of Claims 1 to 7, wherein when viewed in a circumferential direction the front flank of a driving groove is aligned with the rear flank of the following driving groove.

9. A tool according to any one of Claims 1 to 8, wherein the tool shank has a diameter of about 10 mm. 18/03/03,mci 3246.speci,7 -8- A tool according to any one of Claims 1 to 9, wherein the metal material of the tool has a tough composition and/or is set tough at least in the region of the insertion end, in particular in the region of the flanks of the driving grooves.

11. A tool for a hand-held power tool substantially as hereinbefore described with reference to the accompanying drawings. DATED this 18 th day of March, 2003 GEBRUDER HELLER DINKLAGE GmbH By Their Patent Attorneys: CALLINAN LAWRIE 18/03/03,mcl 3246.speci,8