GB1166480A - Improvements relating to the Manufacture of Shafts and other Elongated Members - Google Patents

Abstract

1,166,480. Grinding. MITCHELL SHACKLETON & CO. Ltd. 6 Nov., 1967 [6 Dec., 1966; 11 Feb., 1967], Nos. 54503/66 and 6633/67. Heading B3D. A method of supporting a shaft or other elongated member of substantial length and weight while machining operations are carried out on it consists in mounting the shaft between centres or equivalent means in a machine incorporating means for rotating the shaft and suspending the shaft from an elevated support independent of the operative parts of the machine by mechanical means incorporating a weight or weights by which the weight of the shaft is continuously counter balanced as it rotates. A rigid gantry adapted to span a machine and bodily movable in a direction at right angles to the longitudinal axis of the machine comprises a longitudinal member 10 longer than the machine and having at each end a pillar 11 and a transverse member 12. Flanged wheels 14 housed in the members 12 run on rails 15 on the workshop floor and are driven by an electric motor 16. The pillars 11 support a horizontal girder 19. A track 23 is supported at each end by parts slidably guided for vertical movement in the upper ends of the pillars 11. Trolleys 24 travel on the track and can be located in any desired position therealong. Pivotally mounted on each trolley is a beam 25, to one end of which is pivotally attached a rod 26 terminating in a hook 26<SP>1</SP> and to the other end of which is attached by a flexible member 29 a rod 28 carrying a counterbalance weight 27. Screw jacks 31 operate vertically movable assemblies 32 which when raised engage the beams 25 on opposite sides of the track and lift the track, trolleys and beams as a unit while holding the beams and weights locked against angular movement; the jacks are operated by an electric motor 35 mounted on the girder 19. A lathe headstock is shown at 36, a crank-shaft crank pin at 37 and a journal of the shaft at 38. A crank-shaft having been brought to a position in front of the machine, the gantry is moved forwardly over the crank-shaft and clear of the machine and the track lowered until the hooks 26<SP>1</SP> can be engaged around the journals 38 of the shaft. The track is then raised to lift the shaft and the gantry moved rearwardly to bring the shaft into position for mounting in the machine for rotation about the crank-pin 37 which is then ground by a grinding wheel 39. The counterbalance weights acting in the different hooks may be adjusted according to their position along the shaft, but the sum of all the weights is substantially equal to the weight of the shaft. The hooks 26<SP>1</SP> may have linings of material of low coefficient of friction; they may be replaced by split bearing rings. In a modification, the beams may be rigidly mounted on the trolleys; each beam has pulleys on its opposite end, and a cable passing over the pulleys has a hook or ring at one end and a counterweight at its other end. The gantry may be mounted on overhead rails.