GB436350A - Improvements in or relating to rotatable work supports or tables - Google Patents

Abstract

436,350. Tarrets. STEVENS, A. H., 5, Quality Court, Chancery Lane, London.- (Sundstrand Machine Tool Co. ; 2531, 11th Street, Rockford, Illinois, U.S.A.) March 12, 1935, No. 7735. [Class 83 (iii)] A turret or indexable work-holder for removable attachment to the table of a milling &c. machine comprises a base 10 carrying a rotatable table 11 which may be indexed in one or more positions, e.g. to present work secured thereon either to a machining position or to a loading and unloading position. The table rests on bearing surfaces 12, 13 on the base and has a central pivot 16 secured thereto by a nut and lock nut 23 and covered by a removable plate 26. A clamping member 33 on the base has an arcuate V-shaped surface 34 engaging similar surfaces on the base and table to clamp them together at the working station. The clamping member 33 is operated by parallel rods 52, Fig. 2, secured thereto by nuts 53 and provided with slots engaging pins 55 on levers 54 which are pivoted to the base at 56 and are actuated by a slot in a bar 50 slidable in the base. A pair of toggle links 44, 45 are pivoted respectively to the base and the bar 50 at 47 and 48 and have a common pivot 46 engaging a slot in a rack bar 43 movable transversely in the base by a pinion 41 and hand lever 40. One end of the bar 50 carries a pin 51 secured to a plunger 30 which is engageable with one of a pair of recessed members 31 on the table to lock it in the indexed position. The bar 50 slides through a slot 62, Fig. 3, in the pivot 16 and is provided with a cam surface 63 engaging a roller 60 on the pivot so as to clamp the table at the centre. Rotation of the handle 40 in one direction slides the bar 50 to the right in the Figures, thereby simultaneously clamping the table at the centre and at the end by means of the clamp 33 and also forcing the plunger 30 into the recessed member 31, whilst rotation in the opposite direction releases the clamps and the member 31 and allows springs 70 engaging a ball thrust bearing 72 to raise the table off the surfaces 12, 13 and allow easy rotation thereof by hand to the next indexing position. The base is provided with clearance at 34<1> to permit the table to rise. Location of the table at the indexing position is facilitated by means of a vertical spring plunger in the base coacting with a plunger 82, Fig. 2, projecting beneath the table. The active ends of the plungers are bevelled at one side and stepped at the other side so that as the table is rotated past the indexing position the lower plunger will be cammed downwards whereupon a reverse rotation of the table will bring the stepped surfaces into contact to locate the table accurately. The table may be provided with more than two index positions, and the positions of the spring plunger and the plunger 82 may be reversed.