GB2209494A - Drilling chuck - Google Patents

Description

r v DRT"rI,ING CHUCK i.L The invention relates to a drilling chuck for

hammer drills and/or rotary drills comprising clamping jaws which for c-'LamDJng purposes can be J -- brought to bear against the drill shank and which are displaceable for clamping and loosening purposes by way of a screw-threaded ring which is connected to a gripping sleeve and which is mounted rotatably on the body of the drilling chuck in a peripheral groove, wherein a rotary drill can be fixedly clamped all the cylindrical drill shank and a hammer drill can be non-rotatablv but axially dis-olaceably -.!-ami)ed with a -orofiled drill shank, wherein for t-he -purposes of securing the arrangement to prevent slackening in the hammer drilling mode there are provided at- least one retaining member and a plurality of retaining recesses which relative to the sorewthreaded ring and.he body of 'he d.-i-'ling chuck are arranged -peripherally and equally spaced in a st-ationary position at- the end; of the gr4r,-cing sleeve and a.-e held in engagement by a spring to form a retaining securing means.

Such a drilling chuck is described in German laid-o-pen a-D-olication (DEOS) No. 'AL 25: 'The retaining recesses are arrange, --n equidlstant relationshi-o at the end of the gripping sleeve, at the periphery thereof. In order to provide a defined p-,ay between the clamping jaws and the urofilled drill shanlk of the tool, it is provided that for example three retaining members are disposed in a ring, r"ative to the retaining recesses, the retaining e L members being arranged in displaced relationship with each other at angles of 125', 125 and 110. That arrangement means that a relatively close retaining action can be achieved and rotation of the 2 5, ko 7,399 2L 2 0) 9 4 9 lt 399 screwthreaded ring through 5' corresponds in t-hat arrangement to a change in the clamping diameter of the clamping jaws of about 0.015 mm. The drilling chuck can be fully tightened for clamping a hammer drill and after having been fully tightened can be slackened again by an entire retaining division or sector, thereby ensuring that a guide clearance of between 0.011"; and 0.03 mm is provided.

Upon any relative rotary movement as between the body of the drilling chuck and the gr4-o-cing sleeve, the retaining members are moved over the reta-ining re-cesses, thereby giving rise to U,oublesome noise and meani-nR that an additional -'U-,arn-4nR moment has to be applied. That is the case in narticular w.h-en a drill with w4-+vl-,., a relatively 1 - for a large too or drill shank has to substituted drill- of smaller diameter.

To avoid those disadvantages, the present invention is based on the iDroblem of so improving a drilling chuck of the kind set forth in the oDening Dart of this suecification that a Dro "iled shank of a hammer drill' can be clamDed with a radial guide clearance wh-c"- is defined as accurately as possible, wherein for fixing the clearance a retaining means is brougInt into engageme-nt, which permits the,.e-Dlacemen'. of dril's oP di-P-1"erent sizes with d,-il' shanks of correspondingly different sizes, without additional application of -force or rotary moment without giving rise to troublesome noise.

To solve t-hat problem the invention provides that the retaining securing means automatically comes into engagement upon clamping the tool only when the clamping jaws bear against the tool shank and that the retaining securing means can be non-retainingly overcome, for unclIamping the tool, 355 4 m 7700 -1 1 - - after a first release movement.

in advantageous developments that can be effected in that -here is a defined play between 'he screwthreaded ring and the groove.

Further advantageous embodiments of the invention are set forth in the subsiduary claims and are described in greater detail with their advantages in the --following description. in the accompanying diagrammatic drawing:

Figure 1 is a view in longitudinal section through a drilling chuck, and 2 is a further view in longitudinal. section which is displaced through 9C relative to the view shown in Figure 1.

in the single embodiment illust-rated, the drilling chuck comprises a hollow body 1 in which three clamping jaws 2 are movable in known manner by means of a divided screwthreaded ring 3 in bores inclined to the axis of the chuck. The screwthreaded ring 3 is fitted on the body 1 of the drilling chuck in a peripheral groove L and is rotatable by way of a cupshaped gripping sleeve I. -Provided between t-he groove L and 'he screwthreaded ring 3 is a de--""ned axial play 25 which, when the clamping jaws 2 are not in the clamping condition, makes the gripping sleeve axially movable until the end face 30 of the gripping sleeve 5 comes to bear against the end face 31 of the groove A. The end 06 of the gripping sleeve provides an aperature 7 through which a cylindrical portion 8 c:P the body 'I of the drilling chuck extends, being concertrically guided thereby.

in addition, a ring 9 is also a matching -Pit on the cylindrical portion 8 and is fixed on the L body 1 c±" the chuck by mea.ns of two screws 110. The screws 110 -oass through the wall of the hollow body 1 3 3 9 0, A of the chuck and proJect with their tapering end portions 1 1 into matching conical bores 12 in the wall of a hollow drilling spindle 13 and hold the drilling chuck on 'he drilling spindle 1"I. An anvil 14 is axially displaceably guided in the drilling spindle 13. The anvil 14 applies axially directed blows to the shank 16 of the tool (drill) 15 which is held by the clamping jaws 2 (Pigure 2), by way of a hammer mechanism (not shown) in known fashion for the hammer drilling operation. However the shank 16 is not fixedly clamped but is guided dis-olaceably, with a slight radial -oly, in the axia di-rection by a given amount for the hammer drilling operation, as is known for exmple from Germ.an laid -!ication 0. However o-oer, a7o- (DE-OS) No. 34 25 736 profiling 32 on the shank 116 ensures that the tooll cannot- rotate in the body 1 of the chuck.

31 5 i m -Pour retaining recesses 17 are made Twe nt Y in the illustrated example in the end 06 of the gripping sleeve 5, the recesses being distributed at t-he periphery thereof. Retaining members 10. are axially displaceably fitted in the end face of the ring 9, in bores 18 in the form of blind bores. The ends of the retaining members 10 which -project out of the bore 18 are rounded off and matched to the retaining recesses 17. Latching engagement of the retuaining members 19 with one of the retaining recesses 17 can be produced in each case by means of respective springs 20.

Por that purpose, as shown in Pigure 2, the tool 15 is fitted with the shank- 16 and the profiling 32 into the drilling chuck in such a way that the profiling 32 comes to lie beneath the clamping jaws 2. The gripping sleeve 5 is turned until the clamping jaws 2 engage into the T C, I.

4 -0 m l! profiling 32 on the shank 16.

1 1 " 2 - 5.

a 3 7 9- -0 Further rotary movement of the gripping sleeve 5 has -he result, that -he screwthreaded ring '3, is screwed rearwardly by virtue of the clearance 215 and thus the gripping sleeve 5 and the retaining recesses 17 disposed in the end thereof come into engagement with the retaining members 10 and are pressed thereagainst by the spring 20 to form a retaining securing means.

The screwthreaded ring 7. is screwed -earwardly until its end -"ace 70 comes to bear against the end face '7 1 of -he groove 4. The clamping jaws 2 hold -he shank 105 firmly clamped in that condi-lion. m-he clam-Ding action on the shank 16 is released by sli.-h-'-T slackening the g:.icuing sleeve The shank 16 can move axially. The spacing of the retaining means is so selected that a reverse rotary movement by one ret-ain.ing division or sector -oroduces a variation in the clam-,.-ng diameter of the clamping jaws 2 of about mm, which has been found to be the ontimum guide clearance.

EY virtue of the screwthreaded -Ditch of the screwthreaded ring 3, which is selected in the usual fashion, with a suitable angle in respect of the clamping jaws 2 in -he body 1 of -he drilling chuck, a rotary movement of the gripping sleeve 5 through about 50 is usually necessary in order to Produce a variation in clamping diameter of 0.015 mm. With an arrangement having for example twenty four retaining 17 however the retailning spacing of -he recesses is 15. order now to provide a retaining step of 50, the ring 9 has t-hree retaining members 109, more -oar-.icu';_a-ly at angular spacings of f 1100.

1250 and a -emaJning angle o The reaction moment in hammer drilling of recesses retaining .-:0 6 - 9700 .1 -1 - ' the tool 15 is not t,-ansm4tted to the screw-1-hreaded ring 7 by way of 'he screwthreaded but goes d4,-ectly from 'he clamping jaws 2 into the body 'It of the drilling chuck so that in the event of hard impacts, there is no self-loosening or slackening force that is transmitted to the screwthreaded ring 3 and the gripping sleeve 5 so that just a relatively low retaining force is adequate to prevent undesired dis-placement of the gripping sleeve 5 due to the impacts -produced in the rotary drilling mode. That liable clain-oing of the tool.

e nsure s re L.L When the gripping sleeve - is -u-arne,-' back --pping s'eeve 5, ...ough a retaining division, the g together with the screwthreaded ring -pressed towards the right with the force of the spring 20.

The clamping jaws 2 are pressed radially against the shank 16 of the drill- a force component corresponding to t-he inclination of the clampi.nF- -iaws 2 relative to the longi-'U--,id'-lna'L axis of the drilling chuck. As however the -force of the s-oring 20 is relatively slight, that component is not significant-.

Nonet-helless the tool 15 can perform the lonR-iu,-,d-4na--' movements which are -produced by the anv--:11 14 and the retaining means remains in the condition of e ngageme When the gripping sleeve 5 is turned back by a retaining spacing, the retaining securin.g means comes out of- engagement as t-he gripping sleeve 5 can be lifted away -from the retaining members 10 with -the retaining recesses 17, due to the axji-a^-!- clearance 25. In that connection the dimensions of the soac-4nRs must be so selected that the gap between the ring 9 and the end D' is greater luhan the clearance 25. in addition the retaining members 101 must. be peened or caulked in such a way that the distance by whilch 'Whey k, d' 7-zoo,'---1 - 11i 1 i 7 project beyond the end face of the ring Q is no greater than the gap between the ring 9 and the e nd 6. In that way a change of tool can be carried out without troublesome noise and without applying additional turning moment, if for example a hammer drill with a small shank 16 is to be substituted for a hammer drill with a larger shank.

77Q0 8 - r 2 5 3 5 CLATMS 1 - A drilling chuck for hammer drills and/or rotary drills comprising clamping jaws which- for clam-ping -.,,ir-ooses can be brought to bear against the drill shank and which are displaceable for clamping and loosening purposes by way of a screwthreaded ring which is connected to a gripping sleeve and which is mounted rotatably on the body of the drilling chuck in a peripheral groove, wherein a rotary drill can be fixedly clamped at the cylindrical drill shank and a hammer drill can be non-rotatably but axially d-Ls-.laceably clam-oed with a -orofiled drill shank, wherein 'or the -our-noses of securing the arrangement o p revent slackening in the hammer drilling mode there are provided at least one retaining member and a plural-i-ty of retaining recesses which rellative to the screwt-hreaded ring and the body of the drilling chuck are arranged peripherally and equally spaced in a stationary position at the end of the gripping sleeve and are held in engagement by a spring to form a retaining securing means, wherein the retaining securing means automatically comes into engagement u-Don clamping the tool only when the clamping jaws bear against the tool shank and the retaining securing means can be non-retainingly overcome, for unclamping the tool, after a first release movement.

Claims (1)

1. 2. A drilling chuck according to Claim 1 wherein engagement or release of

   the retaining securing means can be effected by means of a clearance defined between the screwthreaded ring and the groove.

   3. A drilling chuck according to Claim 1 or Claim 2 wherein the constant retaining spacing by virtue of the mutal arrangement of -15he retaininpmembers and the retaining recesses is so selected, Z Q G - le -1 7700 -1 having regard to the screwthreaded transmission effect and the angle of dis-'acement of the clamping jaws, that a retaining spacing corresponds to a variation in clamping of the clamping jaws 0, about 0.0115 mm.

   4. A drilling chuck according to Claim 1, 2 or 3 comprising a plurality of peripherally distributed retaining recesses and a plurality of retaining members co-operating with the retaining recesses, said retaining members being irregularly arranp-ed at the iDeripheral -portion in such a way that in each case only one c-' said rietaining members engp-p-es in a recess and uuon a further rotary movement of the screwthreaded ring another 1 retai ni ng membe r e ngage s J n another reta4 n- ng rece ss and the retaining spacing corresponds to the variation in c-"lam-onR diame-15er of the c--1am-oinR jaws of about 0.0191 mm. A drilling chuck according to any one of the preceding claims wherein the chuck is so designed that after the clamuing laws have been brought to bear against the tool shank and after automatic engagement of the retaining securing means, by reverse rotary movement of the gripping sleeve by at most one retaining spacing, the tool shank has a radial clearance of 0.015 mm and +U.'-,e retaining securing means is still in engagement.

   6. A drilling chuck according to Claim 5 wherein the chuck is so designed that after reverse rotary movement of the gripping sleeve by a few retaining spacings, the retaining securing means is no longer in engagement.

   7. A drilling chuck according to Claim 1 constructe, arranged and adapted to operate -antially as herein described w-;th reference to, subst and as shown in, the accompanying drawing.

   Published 1988 at The Patent Office. State House 66 71 High Holborn. London WC1R 4TP. Purther copies may be obtained from The Patent Office,