Patent GB-627096-A (GB)
Title: Milling machine for the manufacture of slotted oil control and like rings
IPC: B23Q39/04
Filed: 1947-03-11
Abstract: 627,096. Making piston-rings; milling. WELLWORTHY PISTON RINGS, Ltd., and WOOLCOTT, A. J. March 11, 1947, No. 6731. [Classes 83 (ii) and 83 (iii)] A milling-machine for cutting a number of angularly-spaced slots in the circumference of a ring, such as a piston-ring, has a corresponding number of cutters spaced round a circle, work-holding means rotated concentrically with the circle of cutters and with a stepby-step motion so as to pause at each cutting station, and automatic means for bringing the ring into a pre-determined angular position relative to the successive cutters so that each cutter will form one of the desired slots. A loading-mechanism more fully described in Specification 627,097, [Group XXX], comprises a pneumatically-operated slide 30, Figs. 1 and 4, which pushes the split-rings 31 from a hopper 29 one at a time under a pneumatically-operated plunger 37 which then forces them through a taper bore 43 to close their gaps and loads the lowest ring into a cylindrical holder 52 on an adjacent carrier 44 on a rotor 13. The rotor 13 is rotated step-by-step by a rotating cam 17, Fig. 7, having a pin 16 which engages notches 15 on the rotor and is held stationary after each partial rotation by a spring-loaded plunger 22 engaging notches 23 between the notches 15, the plunger being withdrawn at the appropriate times by the cam 17 acting through a bell-crank lever 26. The shaft 61, Fig. 5, for each cutting saw 60 is journalled in a slide 64 and is driven from a central shaft 73 through gearing 72, 71, 68, 67 and a telescoping shaft connection 69. The slide 64 is reciprocated by a rod 75 having a pin 76 engaging a cam-ring 77, Fig. 7, on a spindle 20 rotated in unison with the cam 17, the ring having surfaces 79 for advancing the saw, and surfaces 78 for retracting it. To bring each ring into the correct angular position at the cutting stations, each holder 52 has a hollow spindle 46 rotatable in the rotor and is indexed anti-clockwise by a toothed wheel 47 engaging abutments 82, Fig. 3, at each cutting station. One tooth 48a of each wheel 47 has one edge removed so that, at the first cutting station C1, it clears the abutment 82 and the indexing movement given by the next tooth is only that required to space the first slot from the ring gap. At the discharge station D, the tooth 48a clears an abutment 83 so that only a partial anti-clockwise indexing movement is given and at the loading station L, a clockwise movement is given to the wheel 47 by an abutment 49 in order to re-position the tooth 48a correctly for the next cycle. A plunger 51 within the holder 52 has a spring- loaded rod 50 which is fully lowered at the loading station but which is moved up by the rise 55 of a cam surface 54 to raise the ring almost clear of the upper edge of the holder at the cutting stations, at each of which a pneumatically-operated clamp 57, Fig. 5, holds the ring in position to have a slot cut. The movement of the completed ring to the discharge station loads a bent flat spring 87, Fig. 6, (not shown), which, when the clamp 57 is released and the ring is raised above the holder by a further rise in the cam track, discharges the ring into a shoot. Gauged cutters may operate on groups of rings held in each carrier 44.