GB856432A - Improvements in and relating to apparatus for producing the axial grinding spindle movement in internal grinding appliances - Google Patents

Abstract

856,432. Traversing mechanisms for internal grinders. ALLEMANN A.G., H. March 6, 1957 [March 6, 1956], No. 7471/57. Class 60. [Also in Group XXXII] Apparatus for producing axial movement of the spindle of a grinding machine comprises a working piston 26 which is actuated by compressed air through associated control memmembers and is mechanically connected to the grinding spindle 4. The spindle 4 is rotated in bearings 3 which are axially movable in a housing pivotally connected to a plate adapted to be mounted on the cross-slide of a lathe. The spindle is rotated by a compressed air turbine 5 provided with a lug 6, which cooperates with stops 8, 9 during the axial movements of the bearing and spindle, and the bearing is connected by a bolt 27, Fig. 3, to a piston 26, the ends of which are alternately supplied with air pressure. Compressed air is supplied through a connection 12, Fig. 2, to chambers 13, 16, 19, and channels 17, 20 in valves 7, 14 disposed in the respective chambers 16, 19. In the position shown in Fig. 2, the spindle is in its rearward position and the lug 6 has moved the valve 7 to the left by means of the stop 8 to connect the channel 17 to a bore 18, whereby the air pressure urges the valve 14 to the right, and connects the channel 20 to a bore 21 to urge the piston 26 and the grinding spindle also to the right, or forward position. When the lug 6 contacts the stop 9, the reverse process takes place and the spindle moves to the left. Air from the inoperative ends of the valve 14 and piston 26 passes through bores 29, 30 to a silencer 25 where it is led to the spindle bearing to escape to atmosphere and prevent the entry of dust to the mechanism. In order to produce a braking effect on, the spindle movement a piston 32, Fig. 3, is connected to the piston 26 and during its movements causes oil from a reservoir 36 to flow to and from spaces 33, 37 through ball-valves 25, 38. The balls of the valves are spring-urged against the eccentric portion of a rod, which can be rotated by a handle so that the flow of oil through the valves can be adjusted together to control the speed of reciprocation. One end of the rod is located in an adjustable eccentric bearing so that the speed of movement in one direction may be different to that in the other. Recesses 40, 41 are formed in the bearings 48 to provide air cushions which permit the initial speed of movement after reversal to be accelerated for a short distance. The clearance between the piston 32 and bearings 48 is sufficiently large to allow oil to emerge and collect in a reservoir 13<SP>1</SP> where it is supplied to lubricating points by the air pressure.