GB361272A - - Google Patents

Abstract

361,272. Boring - bar machines. VOGTL€NDISCHE MASCHINENFABRIK (VORM. J. C. & H. DIETRICH) AKT.- GES., Plauen, Vogtland, Germany. June 4, 1931, No. 16347. Convention date, June 12, 1930. [Class 83 (iii).] Lathe and like drivers ; tailstocks.-A boring-machine in which the work holder is rotatably and slidably mounted, but only rotates before the machining operation for centring the work, is designed or finishing work such as bearing bushes with a rapidly rotating diamond tool. The drive to the diamond holder 3 is from a self-contained electric motor 2 through a resilient coupling 10 to an intermediate shaft 11 carried in a fixed bearing 16, the driving end of this shaft comprising a mandrel 4, sleeve 13 with driving fingers 15 which engage grooves in the diamond holder, and a centre, which, together with another spring- pressed centre 5 mounted in the tailstock 6, constitute the supporting means for the tool holder. The work-holding means comprise a chuck 17 fixed to a hollow shaft 19 rotatably mounted in a bearing sleeve 20; over the outside surface of this sleeve slide a pair of oppositely disposed pistons 46, 47 and when fluid pressure is supplied between the latter, they are moved apart and force two tapered rings 21, 22 between the hollow shaft and the housing 23 thereby locking the chuck in fixed position. The slide 26 carrying the housing 23 is operated by fluid pressure in a cylinder 29 and is controlled by a handle 31, throttling valves 38, 39, for varying the speed of feed and return, and also a stop gear 35, 36 which disconnects the slide actuation when the slide has reached its final position. The oil required for the pressure system is obtained from a pump 40 driven by an auxiliary motor 41 which also serves to drive the chuck through the belt means 54 when the work is being centred. A control element 49 gives the required pressure regulation to the locking mechanism for the chuck, the pressure being byepassed when the chuck is to run loose. Wear of the tailstock is prevented from affecting the position of the centre 5 by the locking means 56 being arranged to press the centre carrier against the upper wall of the bore in which it slides.