GB2214455A

GB2214455A - Drilling chuck

Info

Publication number: GB2214455A
Application number: GB8826571A
Authority: GB
Inventors: Guenter Horst Roehm
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-01-14
Filing date: 1988-11-14
Publication date: 1989-09-06
Anticipated expiration: 2008-11-14
Also published as: GB2214455B; GB8826571D0; IT8919047A0; DE8800322U1; IT1228207B; FR2625930A1; ES1009428Y; ES1009428U

Abstract

To protect an operator's hand when adjusting a clamping sleeve (4) for setting jaws (3) of a drilling chuck when the drilling spindle is rotating, a braking ring (15) which can be gripped by hand is rotatably mounted on the sleeve (4) for braking and holding the sleeve. The ring is formed with axial slots (17) to enable it to be compressed on to the sleeve. In an alternative arrangement mating conical braking surfaces are formed on the braking ring and clamping sleeve to be brought manually into engagement against spring action by axial movement of the braking ring. The braking ring is used with a self-tightening chuck, as shown, or with a key-operated chuck. <IMAGE>

Description

DRILLING CHUCK The invention relates to a drilling chuck comprising a chuck body which is designed for connection to a driven drilling spindle, chuck jaws and a clamping sleeve which is rotatably carried on the chuck body for adjustment of the chuck jaws.

A very wide range of different constructions of drilling chucks of that kind are known, in particular in the form of self-tightening or retightening drilling chucks or in the form of drilling chucks for key tightening, having a ring of teeth on the clamping sleeve, for engagement with the tightening key. A common aspect of all those drilling chucks is that the clamping sleeve must be turned relative to the chuck body for adjustment of the chuck jaws. That can be achieved in a partiuclarly simple and rapid fashion in that the clamping sleeve is held fast by hand and the chuck body is driven by way of the drilling spindle by actuating the drilling machine in the clockwise or anticlockwise direction.However skill and practice are necessary if, when the drilling chuck is moving, the clamping sleeve is to be gripped by hand and stopped, or released at the proper time, when the chuck jaws bear against the shank of the tool and thereby the rotary movement of the clamping sleeve on the chuck body, in the direction of rotation for tightening same, abruptly stops. In that situation there is inevitably a considerable risk of injury to the hand.

The invention is based on the problem of so designing a drilling chuck of the kind set forth in the opening part of this specification that the clamping sleeve thereof can be gripped, braked and held, even when the drilling chuck is moving, without the risk of injury to the hand, in order to adjust the chuck jaws when the drilling spindle is moving and/or to pretighten the tool or to release the tool clamping effect.

In accordance with the invention that problem is solved in that a braking ring which can be gripped by hand is rotatably guided coaxially on the clmaping sleeve on the outside thereof, wherein braking surfaces which bear against each other are provided on the braking ring and the clamping sleeve, and that the braking ring can be pressed by hand against the clamping sleeve at the braking surfaces.

The braking sleeve normally bears against the clamping sleeve at the braking surfaces only under a light pressure so that the frictional engagement between the braking ring and the clamping sleeve is low. Therefore, even when the drilling chuck is turning, the braking ring can be readily gripped and held fast by hand, in which case the clamping sleeve then rotates with the chuck body in the braking ring.If however the braking ring is actuated by hand in such a way that the braking pressure at the braking surfaces increases, the clamping sleeve can be acted upon by a correspondingly increasing braking moment, in which case it is easily possible, by means of the force applied by hand to the stationary braking sleeve, to regulate the braking moment acting on the clamping sleeve in a very precise and sensitive fashion and to adapt it to the respective operating conditions when tightening or releasing the drilling chuck.

A preferred embodiment of the invention is characterised in that the braking ring can be radially resiliently compressed and for that purpose has axial slots which are open, at at least one of its edges.

Desirably, the axial slots which are disposed in succession in the circumferential direction of the braking ring are open alternately towards one edge of the ring and towards the other edge of the ring so that the braking ring may be uniformly radially compressed over the whole of its axial width. At any event the braking ring can then be radially compressed in such a way that the respectively desired braking moment is produced at the clamping sleeve.

The braking ring is preferably guided axially nondisplaceably on the clamping sleeve. In an advantageous embodiment, that can be achieved in that the braking ring has a radially inwardly directed annular flange which engages into an annular groove in the clamping sleeve.

Another advantageous option is characterised in that the braking ring is guided axially between an annular shoulder on the clamping sleeve and a securing ring which is fitted into an annular groove in the clamping sleeve, and projects radially outwardly beyond the annular shoulder and the securing ring, so that the two cannot impede radial compression of the braking ring by hand. An embodiment which is also preferred is characterised in that the braking ring is fitted into an annular groove in the clamping sleeve and projects radially out of the annular groove. In all cases the axial guide means for the braking ring also provides for stabilisation thereof, if it should have been severely weakened by the axial slots.

With the above-described radial compressibility of the braking ring, the braking surfaces are preferably, even if not necessarily, in the form of cylindrical surfaces which are coaxial with respect to the axis of the chuck. In accordance with the invention however it is also possible for the braking surfaces to be formed by tapering surfaces, and for the braking ring to be movable axially in the direction in which the taper flares outwardly, towards the clamping sleeve. The braking moment is then applied to the clamping sleeve by axially pressing the braking ring against the clamping sleeve by way of the tapering braking surfaces. In that arrangement however the braking ring may also be radially compressible in the above-described fashion if the braking moment applied to the camping sleeve is to be produced both by axial and radial pressure at the braking surfaces.The braking ring is then to be urged by hand axially and radially towards the clamping ring. Desirably, on the side of its braking surface which is in the direction in which the taper extends inwardly, the braking ring has a radially inwardly directed annular flange which is acted upon by a spring force in the direction in which the taper extends inwardly and which is supported in the opposite direction against the clamping sleeve. The spring force may be produced by a plate or diaphragm spring and the support may be provided by a securing ring, both of which are fitted into annular grooves in the clamping sleeve.

If the drilling chuck is a chuck in which the clamping sleeve is provided with an end which tapers inwardly towards the drill, the braking surface on the clamping sleeve may be formed directly by that tapering surface.

In order that the invention may be clearly understood and readily carried into effect drilling chucks in accordance therewith will now be described, by way of example, with reference to the accompanying drawings, in which: Figures 1, 3, 5 and 7 are views which are partly in axial longitudinal section and p#artly side views of drilling chucks; Figures 2, 4, 6 and 8 are views in cross-section taken respectively along lines II-II, IV-IV, VI-VI and VIII-VIII in Figures 1, 3, 5 and 7; Figure 9 is a view in axial section through a member of the drilling chuck shown in Figures 1 and 2 on an enlarged scale; and Figure 10 is an end view of the member shown in Figure 9 in the direction of the arrow X shown therein.

In each drilling chuck shown in the drawing, the chuck body 1 has a screwthreaded mounting 2 for connection to a drilling spindle (not shown) which can be driven by a drilling machine. Chuck jaws which serve to clamp a drilling tool which is also not shown are identified by reference numeral 3. In order to be able to adjust the chuck jaws 3 for clamping or releasing the drilling tool, a clamping sleeve 4 is guided rotatably on the chuck body 1. When the clamping sleeve 4 is rotated relative to the chuck body 1, the chuck jaws 3 are displaced in their guides 5 by a clamping screwthread 6. The embodiments shown in Figures 1 to 6 illustrate self-tightening or retightening drilling chucks with a clamping screwthread 6 which is arranged conically on the chuck body 1 and which is engaged by the chuck jaws 3 by means of respective transverse tooth arrangements 7.In those chuck designs the chuck jaws 3 are guided directly in the clamping sleeve 4. In addition, a locking ring 8 is arranged axially displaceably and substantially non-rotatably on the chuck body 1. The locking ring 8 is prevented from rotating by a pin 10 which is fixed in the chuck body 1 and which engages into an axial slot 9 in the locking ring. In the axial direction the locking ring 8 is subjected to the force of a spring 11 which urges the locking ring axially into a ring of teeth 12 provided on the clmaping sleeve 4. In that case, with the locking ring 8 in engagement with the teeth 12, the clamping sleeve 4 cannot be rotated relative to the chuck body 1, thereby preventing accidental re-tightening or accidental release of the drilling chuck. Drilling chucks of that kind are described in detail for example in patent specification No.DE-A-3727147 which is part of the state of the art which is not a prior publication, and they therefore do not need to be described in greater detail herein.

Figures 7 and 8 show a drilling chuck with key tightening. Provided on the chuck body 1 is a guide mounting 13 for tighening key (not shown) which engages by means of a pinion thereon into a ring of teeth 14 on the clamping sleeve 4. The member 14 in turn carries the clamping screwthread 6 for the chuck jaws 3 which are guided in the chuck body 1. When the clamping sleeve 4 is turned relative to the chuck body 1 by hand or by means of the key, the chuck jaws 3 are displaced in their guide means 5 by way of the clamping screwthread 6 on the member 14.

In all the illustrated embodiments, a braking ring 15 which can be gripped by hand is rotatably guided coaxially on the clamping sleeve 4 on the outside thereof.

Braking surfaces 16 which bear against each other are provided on the braking ring 15 and on the clamping sleeve 4. The braking ring 15 can be pressed by hand against the clamping sleeve 4 at the braking surfaces 16 whereby the frictional engagement beween the braking surfaces 16 can be correspondingly increased and an increasing braking moment can be applied to the clamping sleeve 4. In the embodiment shown in Figures 1, 2 and 5 to 8, the braking ring 15 is radially resiliently compressible, for which purpose it is provided with axial slots 17 which are disposed in succession in the circumferential direction of the braking ring and which are open alternately towards one edge of the ring and towards the other edge of the ring. The braking ring 15 can therefore be uniformly radially compressed over the whole of its axial width.

The braking ring 15 is also guided axially nondisplaceably on the clamping sleeve 4, which imparts the necessary stability thereto, in spite of the presence of the axial slots 17. In the embodiment shown in Figures 1 and 2 the braking ring 15 has a radially inwardly directed annular flange 18 which engages into an annular groove 19 in the clamping sleeve 4. In the embodiment shown in Figures 5- and 6 on the other hand the braking ring 15 is guided axially between an annular shoulder 20 on the clamping sleeve 4 and a securing ring 21 which is fitted into an annular groove 22 in the clamping sleeve 4. In that case the braking ring 15 projects radially outwardly beyond the annular shoulder 20 and also the securing ring 21 so that the annular shoulder 20 and the securing ring 21 do not prevent the braking ring 15 from being radially compressed.In the embodiment shown in Figures 7 and 8 the braking ring 15 is fitted into an annular groove 23 in the clamping sleeve 4 and also projects radially out of the annular groove 23. In all those embodiments the braking surfaces 16 are formed substantially by cylindrical surfaces which are coaxial with respect to the axis of the chuck.

In the embodiment shown in Figures 3 and 4 on the other hand the braking surfaces 16 are formed by tapering surfaces. The braking ring 15 is axially movable in the direction in which the taper flares outwardly, that is to say, towards the drilling spindle, against the clamping sleeve 4. For that purpose, on the side of its braking surface which is in the direction in which the taper extends inwardly, that is to say towards the drill, the braking ring 15 has a radially inwardly directed annular flange 24. The annular flange 24 is urged by a spring force in the direction in which the taper extends inwardly, that is to say towards the drilling tool, and is supported in the opposite direction against the clamping sleeve 4. The spring force is produced by a plate or diaphragm spring 25 and the support is provided by a securing ring 26. The plate or diaphragm spring 25 and the securing ring 26 are fitted into annular grooves in the clamping sleeve 4. In this embodiment the clamping sleeve 4 is provided with an end 27 which tapers inwardly at the drill side. The braking surface 16 on the clamping sleeve 4 is formed directly by that tapering surface.

Although in that embodiment the braking ring 15 does not have any of the above-described axial slots 17 so that it is comparatively stiff in the radial direction and performs its braking function only upon being axially displaced, it will be appreciated however that it is possible in this case also for the braking ring 15 to be provided with axial slots 17 in the above-described manner so that the braking effect can also be produced by radial compression of the braking ring 15.

Claims

CLAIMS:

1. A drilling chuck comprising a chuck body which is designed for connection to a driven drilling spindle, chuck jaws a clamping sleeve which is rotatably carried on the chuck body for adjustment of the chuck jaws and a braking ring which can be gripped by hand and which is rotatably guided coaxially on the clamping sleeve on the outside thereof, wherein braking surfaces which bear against each other are provided on the braking ring and the clamping sleeve, and the braking ring can be pressed by hand against the clamping sleeve at the braking surfaces.

2. A drilling chuck according to Claim 1, in which the braking ring can be radially resiliently compressed and for that purpose has axial slots which are open, at at least one of its edges.

3. A drilling chuck according to Claim 2, in which the axial slots which are disposed in succession in the circumferential direction of the braking ring are open alternately towards one edge of the ring and towards the other edge of the ring.

4. A drilling chuck according to any one of Claims 1 to 3, in which the braking ring is axially non-displaceably guided on the clamping sleeve.

5. A drilling chuck according to Claim 4, in which the braking ring has a radially inwardly directed annular flange which engages into an annular groove in the clamping sleeve.

6. A drilling chuck according to Claim 4, in which the braking ring is guided axially between an annular shoulder on the clamping sleeve and a securing ring which is fitted into an annular groove in the clamping sleeve and projects radially outwardly beyond the annular shoulder and the securing ring.

7. A drilling chuck according to Claim 4, in which the braking ring is fitted into an annular groove in the clamping sleeve and projects radially out of the annular groove.

8. A drilling chuck according to any one of Claims 1 to 3, in which the braking surfaces are formed by taper surfaces and that the braking ring is movable axially in the direction in which the taper flares outwardly, towards the clamping sleeve.

9. A drilling chuck according to Claim 7, in which on the side of its braking surface which is towards the direction in which the taper extends inwardly, the braking ring has a radially inwardly directed annular flange which is urged by a spring force in the direction in which the taper extends inwardly and is supported in the opposite direction by way of the clamping sleeve.

10. A drilling chuck according to Claim 9, in which the spring force is produced by a diaphragm spring and the support is provided by a securing ring the diaphragm spring and securing ring being fitted into annular grooves in the clamping sleeve.

11. A drilling chuck according to any one of Claims 8 to 10, in which, in the case of a clamping sleeve in which the end tapers inwardly towards the drill the braking surface is formed directly by the inwardly tapering surface.

12. A drilling chuck substantially as hereinbefore described with reference to Figures 1, 2, 9 and 10 of the accompanying drawings.

13. A drilling chuck substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.

14. A drilling chuck substantially as hereinbefore described with reference to Figures 5, 6, 9 and 10 of the accompanying drawings.

15. A drilling chuck substantially as hereinbefore described with reference to Figures 7, 8, 9 and 10 of the accompanying drawings.

Amendments to the claims have been filed as follows 1. A drilling chuck comprising a chuck body which is designed to be connected to a driven drilling spindle, chuck jaws, a clamping sleeve which is rotatably carried on the chuck body for adjustment of the chuck jaws, and a braking member which can be gripped by hand and which is rotatably guided coaxially on the clamping sleeve on the outside thereof, wherein braking surfaces which bear against each other are provided on the braking member and clamping sleeve and the braking member can be pressed by hand against the clamping sleeve at the braking surfaces, the braking member being formed in the circumferential direction as a one piece braking ring which is located coaxially outside the clamping sleeve.