Socket for drills with conical shafts.



P. G. LAGERBKCK. SOCKET FOR DRILLS WITH CONICAL SHAFTS. APPLICATION FILED APR-12,1917. mamas; Eyi 14 m if WW f 9 INVENTOR; PGLAQERBMK ATTORNEY. Patented May 29, 1917. same. PER GUSTAF LAeEaBAoK, or sA'rrsJo-nurm'is, SWEDEN. SOCKET FOR DRILLS WITH CQNICAL SHAFTS. Specification of Letters Patent. Application filed April 12, 1917. Serial No. 161,647. To all whom it may concern: Be it known that I, PER GUsTAr LAGER- BACK, a subject of the King of Sweden, residing at Sattsjii-Dufnas, in the Kingdom of Sweden, have invented new and useful Improvements in Sockets for Drills with Conical Shafts, of which the following is a specification, reference being had therein to the accompanying drawing. This invention relates to an improvement in sockets for drills with conical shafts of that class, in which the drill is held by two or more laminae, which are forced against the conical shaft of the drill by means of a sleeve, conical inside and movable longitudinally of the laminae and the shaft of the drill. According to the invention balls are provided between the laminae, one or more of which are free also at their inner ends, and the said sleeve in one circular row around the central line of the socket in order partially to reduce the friction between the sleeve and the laminae partially to permit the free lamina or laminae to adjust themselves in accordance to the conicity of the shaft of the drill. A drill-socket arranged in accordance with this invention is shown in the accompanying drawing, in a longitudinal section, Figure 1, and in a cross section, Fig. 2. Fig. 3 is an end view of the socket. The drill-socket consists of two or more, in the drawing three, laminae 1, 2, 8. One (1) of the said laminae is connected with the spindle 4: of the socket or made integral with the same, while the laminae 2, 3 are free. The said laminae are freely connected with one another in the known manner by means of pins 5 located in transverse recesses provided in the laminae. The said laminae 1, 2, 3 are embraced by a sleeve 6, which is conical inside and is in screwthreaded engagement with the spindle 4, so that, as the sleeve and the spindle are rotated with relation to one another, the sleeve is moved in one or the other direction longitudinally of the socket and forces the laminae against the shaft of the drill, located between the same, or releases the In order to reduce the friction between the sleeve and the laminae a groove 7 is provided in the outer side of the laminae, which extends around the socket and in which balls 8 are located in contact with the sleeve 6. The sleeve 6 actuates the laminae only at the said balls. According to the invention there is only one row of balls between the sleeve 6 and the laminae, which results in the advantage that, at the same time as the friction between the sleeve and the laminae is reduced, the free laminae 2, 3 can oscillate for some extent transversally on the balls respectively and thus adjust themselves to the conicity of different drill shafts. One end of a spiral spring 9 is connected with the sleeve 6, while the other end of the spring is connected with a ring 11, fixed to the spindle 4 by means of a screw 10 or the like. The object of the said spring 9 isto prevent the sleeve 6 from getting loose during the operation of the drill. The outer side of the sleeve 6 is fluted or arranged in any other suitable manner, so that it can be firmly grasped with the hand. For the dis engaging of the drill, while the spindle rotates, one grasps the sleeve 6 and holds the same. The sleeve is then moved longitudinally of the spindle, so that the path of the balls 8 at the sleeve 6 grows Wider and the laminae are permitted to retire from one another, in consequence whereof the drill becomes free and may be removed. If the drilling machine is at a standstill the sleeve 6 must only be rotated for the gaining of the said object. Having now described my invention, what I claim as new and desire to secure by Letters Patent is: In a socket for drills with conical shafts the combination of laminae, one or more of which are free, a sleeve for tightening the laminae around the shaft of the drill and one row of balls located between the laminae and the said sleeve, substantially as described and for the purpose set forth. In witness whereof, I have hereunto signed my name. PER GUSTAF LAGERBAOK. copies of this patent may be obtained for five cents each, by addressing; the Commissioner of Patents, Washington, D. C. Patented May 29, 191?.



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