EP0614731B1 - Tool and toolchuck for handtools - Google Patents

Abstract

The tool for insertion into a tool chuck for handtools which are used for chiselling, rotary drilling and/or rotary percussion drilling has a clamping shank (A) with two axially closed locking grooves (1), two rotary driving grooves (2) which are axially open towards the free end of the clamping shank (A), and two rotary driving faces (3). <IMAGE>

Description

The invention relates to a tool for inserting into a tool holder for chiselling, rotary drilling and / or rotary impact drilling hand tool devices with a circular clamping shank, which has at least one axially closed locking groove, at least one rotary driving groove open axially towards the free end and, at least in the peripheral region of the locking groove, has a rotary driving surface which is open towards the free end of the clamping shaft and runs parallel to the longitudinal axis of the clamping shaft.

Tools and tool holder for hand tools are known from DE-PS 25 51 125, the clamping shank of these tools having one or two axially closed locking grooves and one or two rotational driving grooves open axially towards the free end of the clamping shaft. The tool holder serves to hold these tools and, according to the number of locking grooves, has locking bodies which can be displaced radially and which are designed, for example, in the form of balls. In cooperation with the axially closed locking grooves, the locking bodies serve to prevent the tools from falling out of the tool holder. To remove the tools, the locking bodies can be displaced radially in such a way that they disengage from the locking grooves.

The above-mentioned locking grooves and the locking bodies interacting therewith are not subject to particularly high stresses, since in operation the tool located in the tool holder is practically floating relative to the locking bodies, that is to say the locking bodies, in cooperation with the locking grooves, do not have to transmit any significant forces during operation. Only when the tool is pulled out of a hole in a component must the locking bodies, in cooperation with the locking grooves, ensure the connection between the tool and the tool holder.

The axial driving grooves, which are open towards the free end of the clamping shaft, into the corresponding rotating driving bars are subject to very high loads of the tool holder. These rotary driving grooves together with the rotating driving bars are responsible for the entire torque transmission during the operation of the tool.

The weakness of the known tools and tool holders lies in the wear of the turning driver grooves and the turning driver bars. Particularly on the flank on the entrainment side, ie on the flank which is upstream in the direction of rotation but faces away from the direction of rotation, an extraordinarily high degree of wear occurs. The reason for this wear and tear is the high torque to be transmitted and the constant relative displacement of the flanks of the rotary driving grooves with respect to the flanks of the rotating driving bars. This relative offset arises in particular from the action of an impact load on the tool when chiseling or rotary impact drilling. The wear on the rotary driving grooves on a tool is deflected to such an extent that reliable torque transmission is no longer possible even before the actual operating wear of the tool's working area. This inevitably leads to an expensive replacement of such a tool.

From EP-A-195260 a drill chuck and a tool corresponding to the preamble of claim 1 for rotary and rotary impact drilling are known. The clamping shank of the tool has three rotary driving grooves arranged uniformly distributed around the circumference, of which at least one is designed to be axially closed towards the free end of the clamping shank in order to form a stop against axial falling out of the tool from the chuck.

Rotary driving surfaces are arranged on both sides of the rotary driving grooves. These rotational driving surfaces, which are open towards the free end of the clamping shaft, run parallel to the longitudinal axis of the clamping shaft and are arranged essentially tangentially to the circumference of the clamping shaft. The extent of the rotary driving surfaces in the circumferential direction is different.

The invention has for its object to provide a tool that shows no harmful wear when interacting with a suitable tool holder, so that a reliable torque transmission is guaranteed.

According to the invention, the object is achieved in that the locking groove and the rotary driving surface have overlapping planes of symmetry in the longitudinal direction of the clamping shaft. According to the invention, a tool holder suitable for the tool is also provided.

The rotary driving surface according to the invention forms an additional transmission surface for the transmission of the torque while avoiding a cross-sectional weakening which has a detrimental effect on the strength of the tool. Because the circumferential area of the clamping shaft, in which the locking groove is located, is essentially overlaid by the rotary driving surface, there is no reduction in the rotary driving groove. The essentially radially running flanks of the rotary driving grooves, which serve for torque transmission, are retained in their full size. At least part of the locking groove remains obtained by arranging the rotary driving surface on the clamping shaft. The decreasing stop surface of the locking groove for the axial holding of the tool due to the arrangement of the rotary driving surface is nevertheless so large that the connection between the tool and the tool holder is ensured when the tool is pulled out of a bore in a component through the interaction of the locking body and locking groove.

The required rotary driving grooves and the locking grooves are to some extent a cross-sectional weakening of the clamping shaft. In order not to weaken the area between the rotating driving groove and the locking groove, it is advantageous if the rotary driving surface is opposite the locking groove is arranged such that the locking groove and the rotary driving surface have overlapping planes of symmetry in the longitudinal direction of the clamping shaft.

The rotary driving surface is preferably designed to be flat. Flat surfaces have the advantage that they are easy and economical to manufacture.

In order to achieve the largest possible rotating driving surface, it is advantageous if the rotating driving surface is convex. The cross section of a clamping shank is only slightly weakened by the arrangement of a convexly designed rotary driving surface and the stop surface of the locking groove for the axial holding of the tool is only slightly smaller. Another possibility is to make the rotary driving surface concave. The forces acting on a convex or concave rotating driving surface, which are necessary to set the tool in rotary motion, thus act on a larger surface. This results in a lower surface pressure, which has an extremely positive effect on the wear behavior of the clamping shank.

In order not to impair the size of the areas of the rotary driving grooves that interact with the locking elements of the tool holder, the rotating driving surface preferably consists of two partial surfaces that extend in the manner of a roof. An optimal size of these areas is achieved when the apex of the partial areas is expediently on the circumference of the clamping shaft.

Depending on the size of the torque to be transmitted, the partial areas can have different sizes and different apex angles. With regard to the occurring moments, an apex angle, which is expediently 120 ° to 150 °, has proven itself.

In order to be able to absorb very high torques which do not act on one side on the clamping shaft of the tool, the clamping shaft expediently has two diametrically opposed locking grooves and two rotary driving surfaces. The rotary driving surfaces run parallel to each other. The torque transmission thus serve two rotary driving surfaces and the driving flanks of the rotary driving grooves, which run essentially radially.

So that a torque can act evenly distributed on the circumference of the clamping shank, the rotary driving surfaces are symmetrical.

So that the rotating surfaces can absorb as large a portion of the torque as possible, the rotary driving surfaces are preferably designed such that the length of the rotating driving surface is greater than the length of the locking groove. The entire surface of those areas of the rotary driving surface which project beyond the locking groove serve for torque transmission.

The above-mentioned trained tools have the advantage that they can be used in a conventional tool holder, for example in accordance with DE-PS 25 51 125. In this case, a loss must be accepted, since higher proportions of torques are not transferable, and the rotary driving surfaces remain without function. The circular receiving opening of such a tool holder has at least one rotary driving bar for a rotating driving groove and at least one radially displaceable locking body for a locking groove of the tool. The torque to be transmitted can be increased if the tool is inserted into a tool holder according to the invention with a receiving opening which preferably has at least one counter surface for the rotary driving surface of the tool in the area of the locking body.

An additional torque transmission from the tool holder to the clamping shank of the tool is achieved by means of a corresponding counter surface of the tool holder which is matched to the rotary driving surface of the tool not only possible via the rotary drive bar in connection with the rotary drive groove, but also via the counter surface in connection with the rotary drive surface.

The counter surface is advantageously designed to be flat. Flat surfaces have the advantage that they are easy and economical to manufacture.

In order to be able to reach a receiving opening with the largest possible counter surface, this is preferably concave. The cross section of the receiving opening is reduced by the arrangement of a concave counter surface and the wall thickness of the tool holder increases in the area of the counter surfaces. In this way, an overall stable tool holder is achieved. The receiving opening can also be designed such that the counter surface of the receiving opening is advantageously convex. Both concave and convex counterparts are particularly well suited for the transmission of large forces which are necessary to set the tool in rotary motion, since the forces are distributed over a larger area. This results in a lower surface pressure, which has a positive effect on the wear behavior of the tool holder.

In order to adequately secure the tool - for example in the case of empty blows - the counter surface preferably consists of two partial surfaces running in the shape of a roof. This provides a sufficiently large stop for the locking body of the tool holder. The apex of the partial surfaces preferably lies on the circular contour of the receiving opening, an apex angle of 120 ° to 150 ° having also proven particularly useful.

The guide of the tool holder has an essentially radially extending through hole, which serves to receive the locking body and in which the locking body can be displaced essentially radially. In order to be able to create a greater wall thickness in the area of the through hole for the locking body, it is advantageous if the locking body and the counter surface are arranged in such a way that they have planes of symmetry that overlap in the longitudinal direction of the receptacle.

The tool holder expediently has two locking bodies diametrically opposite one another and two diametrically opposite one another arranged counter surfaces. Such a tool holder is particularly well suited for the transmission of high torques, since two counter surfaces are arranged in addition to the rotary driver. This divides the force that occurs so that there is less surface pressure between the individual, interacting surfaces.

The counter surfaces of the tool holder are designed symmetrically so that the forces generated during the torque transmission can act in a substantially uniformly distributed manner on the circumference of the insert shaft of the tool. The torque is thus transmitted via the rotary drive bars in connection with the rotary drive grooves and the counter surfaces in connection with the rotary drive surfaces.

Fig. 1

eine Ansicht des Einspannschaftes eines Werkzeuges gemäss Erfindung;

Fig. 2

einen Schnitt durch den Einspannschaft der Fig. 1 entsprechend Linie II-II;

Fig. 3

einen Schnitt durch einen weiteren Einspannschaft;

Fig. 4

einen Schnitt durch einen weiteren Einspannschaft;

Fig. 5

einen Schnitt durch eine Werkzeugaufnahme in Verbindung mit einem Einspannschaft gemäss den Fig. 1 und 2;

Fig. 6

eine Ansicht eines weiteren Einspannschaftes;

Fig. 7

einen Schnitt durch den Einspannschaft der Fig. 6 entsprechend der Linie VII-VII.

The invention is explained in more detail below with reference to the drawings, for example. Show it:

Fig. 1

a view of the clamping shaft of a tool according to the invention;

Fig. 2

a section through the clamping shaft of Figure 1 along line II-II.

Fig. 3

a section through another clamping shaft;

Fig. 4

a section through another clamping shaft;

Fig. 5

a section through a tool holder in connection with a clamping shank according to Figures 1 and 2.

Fig. 6

a view of another Einspannschaftes;

Fig. 7

a section through the clamping shaft of Fig. 6 along the line VII-VII.

1 to 4 and 6, 7 each show a clamping shank A, B, C, D of a tool. The clamping shaft A, B, C, D has two axially closed locking grooves 1, 11, 21, 31 and two rotary driving grooves 2, 12, 22, 32 which are open axially towards the free end of the clamping shaft A, B, C, D. How in particular 2, 3, 4 and 7 show, the flanks 2a, 2b, 12a, 12b, 22a, 22b, 32a, 32b of the rotary driving grooves 2, 12, 22, 32 run essentially radially.

In particular, FIG. 1 shows a length ratio between the length L of the rotary driving surface 3 and the length V of the locking groove 1. Those areas of the rotating driving surface 3 which project beyond the locking groove 1 serve with their entire surface for torque transmission.

As illustrated in FIG. 2, the clamping shank A is provided with two symmetrically designed rotary driving surfaces 3 that run parallel to one another. These rotary driving surfaces 3 are flat and extend in the longitudinal direction of the clamping shaft A.

The clamping shaft B shown in FIG. 3 shows two symmetrical, convexly designed rotary driving surfaces 13. These rotating driving surfaces 13 extend in the longitudinal direction of the clamping shaft. The locking grooves 11 and the rotary driving surfaces 13 have overlapping planes of symmetry.

4 shows a clamping shaft C with two symmetrical, concave rotary driving surfaces 23 which extend in the longitudinal direction of the clamping shaft C. The locking grooves 21 and the rotary driving surfaces 23 have overlapping planes of symmetry.

5 schematically shows a section through a tool holder into which the clamping shank A of the tool according to FIGS. 1 and 2 with locking grooves 1, rotary driving grooves 2 and rotating driving surfaces 3 is inserted. The tool holder has a guide 7, an actuating sleeve 8 and a cage 9 encompassing the actuating sleeve 8. By displacing the actuating sleeve 8, either axially or in the circumferential direction, a recess, not shown in the example shown, can be brought into a radial projection of the locking body 5, so that the in a radially extending through bore 10 displaceable locking body 5 can disengage from the locking groove 1 and thereby releases the clamping shaft A, so that the clamping shaft A of the tool can be removed from the guide 7 and thus the tool from the tool holder.

As FIG. 5 also shows, the guide 7 has rotary driving bars 4 which are provided with essentially radially extending flanks 4a, 4b.

The clamping shank D shown in FIG. 6 shows a rotary driving surface 33, which consists of two partial surfaces 33a, 33b arranged in a roof-like manner with respect to one another. The length of the partial surfaces 33a, 33b project beyond the locking groove 31 in the longitudinal direction of the clamping shaft D in both directions. That part, the partial surfaces 33a, 33b, which projects axially beyond the locking groove serves with its entire surface for torque transmission. The partial surfaces 33a, 33b of the rotary driving surface 33 extend over part of the length of the clamping shank D. The angle W of the partial surfaces 33a, 33b arranged in a roof shape relative to one another is 120 ° to 150 °.

The partial surfaces 33a, 33b are formed symmetrically to one another. The locking grooves 31 and the rotary driving surfaces 33 have overlapping planes of symmetry.

Claims (14)

1. Tool for insertion into a tool chuck for chiselling, rotary drilling and/or percussion drilling hand tools, comprising a circular clamping shaft (A, B, C, D) having at least one axially sealed locking groove (1, 11, 21, 31), at least one rotary pickup groove (2, 12, 22, 32) which is axially open towards the free end, and at least in the peripheral area of the locking groove (1, 11, 21, 31) a rotary pickup surface (3, 13, 23, 33) which is open towards the free end of the clamping shaft (A, B, C, D) and extending parallel to the longitudinal axis of the clamping shaft (A, B, C, D), characterised in that the locking groove (1, 11, 21, 32) and the rotary pickup surface (3, 13, 23, 33) have in the longitudinal direction of the clamping shaft coinciding symmetry planes.
2. Tool according to Claim 1, characterised in that the rotary pickup surface (3) is designed to be plane.
3. Tool according to Claim 1, characterised in that the rotary pickup surface (13) is designed to be convex.
4. Tool according to Claim 1, characterised in that the rotary pickup surface (23) is designed to be concave.
5. Tool according to Claim 1, characterised in that the rotary pickup surface (33) is composed of two surface sections (33a, 33b) which extend rooflike relative to each other.
6. Tool according to Claim 5, characterised in that the vertex of both surface sections (33a, 33b) lies on the circumference of the clamping shaft (D).
7. Tool according to Claim 6, characterised in that the vertex angle (W) lies between 120° and 150°.
8. Tool according to one of Claims 1 to 7, characterised in that the clamping shaft (A, B, C, D) comprises two locking grooves (1, 11, 21, 31) which are positioned diametrally opposite each other and two rotary pickup surfaces (3, 13, 23, 33).
9. Tool according to one of Claims 1 to 8, characterised in that the length (L) of the rotary pickup surface (3, 13, 23, 33) is greater than the length (V) of the locking groove (1, 11, 21, 31).
10. Tool chuck for tools according to one of Claims 1 to 9, comprising a circular receiving aperture as well as at least one rotary pickup ledge (4) for a rotary pickup groove (2) and with at least one radially transposable locking element (5) for a locking groove (1), characterised in that the receiving aperture has in the area of the locking body (5) at least one counter-surface (6) for the rotary pickup surface (3) of the tool, and that the locking element (5) and the counter-surface (6) have in the longitudinal direction of the receiving aperture coinciding symmetry planes.
11. Tool chuck according to Claim 10, characterised in that the counter-surface (6) is designed to be plane.
12. Tool chuck according to Claim 10, characterised in that the counter-surface is designed to be concave.
13. Tool chuck according to Claim 10, characterised in that the counter-surface is designed to be convex.
14. Tool chuck according to Claim 10, characterised in that the counter-surface is composed of two surface sections which extend rooflike relative to each other.

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