EP0622157B1 - Clamping shaft of a tool - Google Patents

Description

The invention relates to a tool for inserting into a tool holder for chiselling and / or impact drilling hand tool devices with a clamping shaft that has at least one axially closed locking groove and at least two driving surfaces that deviate from a circular contour and are open axially toward the free end of the clamping shaft, the Cross section of the clamping shaft is designed as a polygonal profile with profile surfaces and that the driving surfaces are arranged in the region of the profile surfaces, and a tool holder for such a tool, according to the preamble of claim 8. Such a tool and such a tool holder are known from DE-U - 9116606.

An axially closed groove with a semicircular cross section is arranged in the tool shank of a drill of the type mentioned at the beginning of DE-PS 25 51 125. The ends of the groove are hollow spherical and a spherical locking body engages in the groove, which is guided in a tool holder radially displaceable. With the help of the locking body, the axial mobility of the clamping shank in the tool holder is limited.

Open driving grooves with driving surfaces are arranged in the tool shaft axially towards the free end of the clamping shaft. These driving surfaces together as with a strip-shaped rotary driver of the tool holder. The strip-shaped rotary driver is fixed in the tool holder.

From DE-A-2826153 a quick-change chuck and a tool for a drilling and chiseling device are known. The clamping shank of the tool has two areas arranged one behind the other with a polygonal profile in the form of a hexagon. Between these two areas, the insertion end has a round cross-section, the diameter of which is smaller than the width across flats of the hexagon. The surfaces of both hexagons serve as driving surfaces when transmitting a rotary movement starting from the tool holder to the insertion end of the tool.

For tools with no working diameter and a relatively large clamping shaft diameter, it is necessary to carry out a strong material deformation or machining in the area of the clamping shaft, which is associated with a great deal of effort. Such a production is uneconomical and expensive.

The invention is therefore based on the object of designing the clamping shank of the tool in such a way that even with a tool with a small working diameter, production can be carried out inexpensively, and the centering of the shank is improved.

The object of the invention is achieved in that the polygonal profile is formed with rounded corners, the guide contour of the clamping shaft being formed by the corner dimension of at least two corners, and in that the locking grooves are located in the area of the profile surfaces. A corresponding tool holder is also provided according to claim 8.

By designing the clamping shank as a polygon-like profile, additional driving surfaces are formed, which serve to transmit the torque. The wear in the area of the clamping shaft is significantly reduced, since the contact area between the clamping shaft and the tool holder is larger in the area of the driving surface. In addition, the production of tools with no working diameter is more economical because less material has to be formed in the area of the clamping shank.

The corners on the circumference between the profile surfaces serve to center the clamping shank in the tool holder. The corners are rounded and thus form a radial guide contour.

At least two driving surfaces are provided on the clamping shaft. By arranging a second or more driving surfaces, a more uniform, central torque transmission is achieved.

In the case of a circular receiving opening of the tool holder, the guide contour is preferably formed by at least two diametrically opposite corners. Instead of just two corners, three corners can also be used as a so-called three-point support, the rounded corners being on the same diameter and being arranged at 120 ° to each other.

In order to ensure that the clamping shank can be guided in the tool holder with low wear, the guide contour is expediently formed by four corners, two corners being arranged diametrically opposite one another.

The greater the number of corners, the lower the individual radially occurring load on a single corner.

Appropriately, at least some of the driving surfaces are essentially radially extending areas of driving grooves that are open axially towards the free end of the clamping shaft. In order to be able to achieve a better torque transmission from the tool holder to the clamping shank, the driving surfaces formed by the profile surfaces have radial recesses which bring about an enlargement of the driving surface.

Turning grooves that have flanks, of which at least the flanks on the driving side run essentially radially, have proven to be particularly advantageous. The flanks form a direct contact surface for the torque transmission acting in the circumferential direction.

Depending on the shape of the tool holder, the polygonal profile of the clamping shank can advantageously be designed as a square polygon. The cross section of such a clamping shank can be essentially square or rectangular. In the case of a square-shaped clamping shank, all the profile surfaces are essentially of the same size. The rectangular clamping shaft has profile surfaces that are of different sizes. If the locking groove is arranged in the area of one of the smaller profile surfaces, the larger profile surfaces are available for the rotary driving. Due to the larger profile areas, it is possible to arrange additional recesses for rotary driving elements.

In order to achieve an enlargement of the profile surfaces, the profile surfaces of the profile of the clamping shank, which is designed as a square polygon, can preferably be convex or concave.

In order to be able to ensure cost-effective production of a clamping shank according to the invention, the clamping shank in its initial state is a press blank with a square or rectangular cross section, which can be brought into its final shape by massive forming. In the case of massive forming, the clamping shank is brought into its final shape by upsetting and pressing.

The tools designed in the manner mentioned above have the advantage that they can be used in a conventional tool holder, for example in accordance with DE-PS 25 51 125. However, this with the loss that higher proportions of torques are not transferable, since the profile surfaces remain without function. The advantages according to the invention, i.e. the possibility of increasing the torque to be transmitted, can be exploited if the tool is inserted into a tool holder with a receiving opening, the cross section of which corresponds to the cross section of the tool and is expediently polygonal, and has polygonal surfaces, at least one of the polygon surfaces cooperates with a driving surface of the clamping shank of the tool and another polygon surface has a passage opening for a radially displaceable locking element which can be connected to the locking groove in the region of the profile surfaces of the clamping shank of the tool.

In order to avoid small wall thicknesses of the guide, the corners of the polygon surfaces are preferably rounded.

At least one polygon surface expediently has an axially extending strip-shaped rotary driver, with essentially radially extending counter surfaces, which cooperate with the essentially radially extending driving surfaces. The arrangement of such rotary drivers results in a better distribution and a better transmission of the torque from the tool holder to the clamping shank of the tool.

The cross section of the receiving opening is expediently designed as a square polygon with polygon surfaces. The essentially symmetrically arranged and essentially symmetrical polygon surfaces and ensure a uniform distribution of the torque on the clamping shank of the tool.

The polygonal surfaces of the square polygon are preferably concave or convex. This creates an enlargement of the polygon areas so that the force transmitted from the tool holder to the clamping shank of the tool is distributed over a larger area. This results in lower surface pressures.

Fig. 1, 3, 5, 7, 9, 11

Querschnitte von verschiedenen Ausführungsbeispielen des Einspannschaftes von sechs verschiedenen Werkzeugen;

Fig. 2, 4, 6, 8, 10, 12

Seitenansichten der Einspannschäfte 10, 12 nach den Fig. 1, 3, 5, 7, 9 und 11 in verkleinerter Darstellung;

Fig. 13

Schnitt durch eine schematisch dargestellte Werkzeugaufnahme mit einem Einspannschaft gemäss den Fig. 3 und 4.

The invention is explained in more detail using exemplary embodiments. Show it:

1, 3, 5, 7, 9, 11

Cross sections of different embodiments of the clamping shank of six different tools;

2, 4, 6, 8, 10, 12

Side views of the clamping shafts 10, 12 according to Figures 1, 3, 5, 7, 9 and 11 in a reduced view.

Fig. 13

Section through a schematically illustrated tool holder with a clamping shaft according to FIGS. 3 and 4.

The clamping shank 1, 10 shown in FIGS. 1 to 4 has an essentially square cross section with profile surfaces of essentially the same size. In the area of two diametrically opposed profile surfaces, locking grooves 2, 19 are arranged, which are closed on both sides in the axial direction. The ends of the locking grooves 2, 19 are each hollow-spherical.

The profile surfaces arranged at 90 ° to the locking grooves 2, 19 form driving surfaces 3, 12 which are used for torque transmission. The one for the exact Centering the clamping shank 1, 10 in a tool holder, not shown, necessary guide contour is formed by the corners 4, 5, 6, 7, 13, 14, 15, 16.

The driving surfaces 12 shown in FIGS. 3 and 4 have axially extending rotary driving grooves 11 which are open towards the end of the clamping shaft 10. The additional arrangement of such rotary driving grooves 11 creates additional, essentially radially running driving surfaces 17, 18, which serve to better transmit the torque from a tool holder, not shown, to the clamping shaft 10.

The clamping shank 20 shown in FIGS. 5 and 6 has a substantially rectangular cross section. Because of this cross-section, the profile areas formed are of different sizes. Axially closed locking grooves 21 are arranged in the area of the smaller profile surfaces. The ends of these locking grooves 21 are hollow spherical.

To form the driving surfaces 22, material deformation takes place in the area of the larger profile surfaces. This is achieved during the manufacturing process in that two axially extending depressions 27 are pressed into the profile surfaces on both sides. In this way, the material displaced reaches the remaining area of the profile surfaces, so that increased driving surfaces 22 are created.

The dashed line shown in FIG. 5 represents the size of a square-shaped press blank 28, as is required for producing such a clamping shank 20. By using square-shaped press blanks 28, a considerable reduction in costs is achieved by saving material. Compared to a round press blank, a square portion of press blank 28 saves a considerable amount of forming work.

The corners 23, 24, 25, 26 form the corresponding guide contour so that the insert shaft 20 with the rectangular cross section can be guided radially precisely within a tool holder (not shown).

7 and 8 also show a clamping shank 30 which is essentially made from a square polygon, two diametrically opposite corners 33, 35 being chamfered and two further corners 34, 36 being rounded. The guide contour necessary for the central guidance of the tool within a tool holder, not shown, is formed by the two diametrically opposite, rounded corners 34, 36. The clamping shaft 30 points at two each other axially closed locking grooves 31 on diametrically opposite profile surfaces. The two further, essentially diametrically opposed profile surfaces form driving surfaces 32. These driving surfaces 32 each have a parallel driving groove 37 which serves to center the tool. This essentially forms additional radial driving surfaces 38.

The clamping shank 40 shown in FIGS. 9 and 10 is designed as a square polygon. The cross section shows essentially the same size, convex profile surfaces. In the area of two diametrically opposed profile surfaces, locking grooves 49 are arranged, which are closed on both sides in the axial direction. The ends of the locking grooves 49 are each hollow-spherical.

The profile surfaces arranged at 90 ° to the locking grooves 49 form driving surfaces 42 which are used for torque transmission. The driving surfaces 42 have axially extending rotary driving grooves 41, which are open towards the end of the clamping shaft 40. The additional arrangement of such rotary driving grooves 41 creates additional, essentially radially running driving surfaces 47, 48, which serve to better transmit the torque from a tool holder, not shown, to the clamping shank 40.

The guide contour of the insertion shaft 40 is determined by the Ekken 43, 44, 45, 46.

The clamping shank 50 shown in FIGS. 11 and 12 has essentially the same size, concave-like profile surfaces. In the area of two diametrically opposed profile surfaces, locking grooves 59 are arranged, which are closed on both sides in the axial direction. The ends of the locking grooves 59 are each hollow spherical.

The profile surfaces arranged at 90 ° to the locking grooves 59 form driving surfaces 52 which are used for torque transmission. The guide contour necessary for the exact centering of the clamping shank 50 in a tool holder (not shown) is formed by the corners 53, 54, 55, 56.

The driving surfaces 52 have axially extending rotary driving grooves 51, which are open towards the end of the clamping shaft 50. The additional arrangement of such rotary driving grooves 51 creates additional, essentially radially running driving surfaces 57, 58, which serve to better transmit the torque from a tool holder, not shown, to the clamping shank 50.

The production of the tool, in which the starting product is a press blank to be formed, is also possible for the exemplary embodiments according to FIGS. 1 to 4 and 7 to 12, it being possible for the cross section of the press blank to be round, square, rectangular or polygon-like.

A tool holder is shown schematically in FIG. 13, in which the clamping shank 10 of the tool according to FIGS. 3 and 4 is inserted. The tool holder has a guide 60 with a receiving opening, an actuating sleeve 73 and a cage 72 surrounding the actuating sleeve 73. By displacing the actuating sleeve 73 either axially or in the circumferential direction, a recess (not shown in the example shown) can be brought into a radial projection of a locking element 67, so that this locking element 67 guided in a passage opening 66 can dodge radially. This means that the locking element 67 can disengage from the locking groove 19 and thereby release the clamping shank 10, so that the tool can be removed from the guide 60 and thus from the tool holder.

The receiving cross section of the guide 60 is polygonal and has the same size polygon surfaces 61, 62. The corners 68, 69, 70, 71 of the polygon surfaces 61, 62 are rounded.

The guide 60 has two axially extending, strip-shaped rotary drivers 63 projecting from the polygonal surfaces 61 into the clear width of the receiving opening and having essentially radially extending counter surfaces 64, 65.

Claims (12)

1. Tool for insertion into the tool chuck of chiselling and/or percussion drilling hand tools comprising a clamping shaft (1, 10, 20, 30, 40, 50) having at least one axially closed locking groove (2, 19, 21, 31, 49, 59) and at least two pickup surfaces (3, 12, 17, 18, 22, 32, 38, 42, 47, 48, 52, 57, 58) which deviate from a circular contour and are axially open towards the free end of the clamping shaft, and the cross-section of the clamping shaft (1, 10, 20, 30, 40, 50) is a polygonal profile with profile surfaces, and the pickup surfaces (3, 12, 17, 18, 22, 32, 38, 42, 47, 48, 52, 57, 58) are arranged in the area of the profile surfaces, characterised in that the polygonal profile has rounded corners (4, 5, 6, 7, 13, 14, 15, 16, 23, 24, 25, 26, 34, 36, 43, 44, 45, 46, 53, 54, 55, 56), and the guide contour of the clamping shaft (1, 10, 20, 30, 40, 50) is established by the corner dimension of at least two corners (4, 5, 6, 7, 13, 14, 15, 16, 23, 24, 25, 26, 34, 36, 43, 44, 45, 46, 53, 54, 55, 56), and the locking grooves (2, 19, 21, 31, 49, 59) are located in the area of the profile surfaces.
2. Tool according to Claim 1, characterised in that the guide contour is formed by at least two diametrically opposite corners (4, 6; 5, 7; 13, 15; 14, 16; 23, 25; 24, 26; 34, 36; 43, 45; 44, 46; 53, 55; 54, 56).
3. Tool according to Claim 1 or 2, characterised in that the guide contour is formed by four corners (4, 5, 6, 7; 13, 14, 15, 16; 23, 24, 25, 26; 43, 44, 45, 46; 53, 54, 55, 56) of which two corners (4, 6; 5, 7; 13, 15; 14, 16; 23, 25; 24, 26; 43, 45; 44, 46; 53, 55; 54, 56) are arranged to be diametrically opposite each other.
4. Tool according to one of Claims 1 to 3, characterised in that at least a portion of the pickup surfaces (17, 18, 38, 47, 48, 57, 58) are essentially radially extending areas of rotary pickup grooves (11, 37, 41, 51) which are axially open towards the free end of the clamping shaft (10, 30, 40, 50).
5. Tool according to one of Claims 1 to 4, characterised in that the polygonal profile is in the shape of a square polygon.
6. Tool according to Claim 5, characterised in that the profile surfaces of the square polygonal clamping shaft (40) are convex.
7. Tool according to Claim 5, characterised in that the profile surfaces of the square polygonal of the clamping shaft (50) are concave.
8. Tool chuck with a receiving opening of a polygonal cross-section and a radially transposable locking element for tools according to one of Claims 1 to 7, characterised in that the cross-section, which corresponds with the cross-section of the tool, comprises polygonal surfaces (61, 62) with rounded corners (68, 69, 70; 71), and that at least one of the polygonal surfaces (61) co-operates with a pickup surface (12) of the clamping shaft (10) of the tool, and that another polygonal surface (62) comprises a passage opening (66) for the radially transposable locking element (67) which can be connected to the locking groove (19) in the area of the profile surfaces of the clamping shaft (10) of the tool.
9. Tool chuck according to Claim 8, characterised in that at least one polygonal surface (61) comprises an axially extending ledgeshaped rotary pickup (63) with essentially radially extending counter-surfaces (64, 65) which co-operate with essentially radially extending areas of the pickup surfaces (17, 18).
10. Tool chuck according to one of Claims 8 or 9, characterised in that the cross-section of the receiving opening is arranged to be a square polygon.
11. Tool chuck according to Claim 10, characterised in that the polygonal surfaces (61, 62) of the square polygon are concave.
12. Tool chuck according to Claim 11, characterised in that the polygonal surfaces (61, 62) of the square polygon are convex.

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