Patent GB-357621-A (GB)
Title: Improvements in internal centerless grinding machines
IPC: B24B5/18
Filed: 1930-06-18
Abstract: 357,621. Centreless grinding. CINCINNATI GRINDERS, Inc., 3058, South Street, Cincinnati, Ohio, U.S.A. June 18, 1930, No. 18664. Convention date, June 28, 1929. Addition to 290,999, [Class 60, Grinding or abrading &c.]. [Class 60.] Round holes, enlarging and trueing ; gauges ; guides and rests; spindle mountings.-A centreless grinding-machine for internal grinding comprises a base 30 having ways 31, 32 thereon, the ways 31 carrying a carriage 33 having mounted thereon a grinding-wheel 37 driven by an electric motor 34, the carriage being reciprocated by a piston 38 hydraulically actuated within a cylinder 39. On the ways 32 is mounted a table 43 movable by a piston 135 in a cylinder 136, and movable on transverse ways on the table is a slids 46 having thereon an angularly adjustable swivel table 49. This table carries in a bracket 53 a regulating-wheel 56, driven through worm and bevel gearing, from a shaft 66. The slide 46 is moved to feed the work to the grinding-wheel by a cam 47 engaging a follower 48 on the slide, the movement taking place against a constant pressure in a cylinder 70 urging a piston rod 72 against a sleeve 60 of the table 49. On the table 49 also is a work-rest bracket 73 carrving a rest 74 for the work 44, which is held against the regulating-wheel by a pressure roll 75 mounted on an inclined axis in a yoke 78 carried by a sleeve 77 in bearings in a bracket 76 ; the roll is urged against the work by a spring pressed plunger acting on an arm secured to the sleeve. Within the sleeve is a shaft 90 carrying a gear sector 89, which actuates an ejector arm 92 carrying a finger 94 adapted to engage and lift the finished work-piece, this, during its upwards motion, engaging a detent 98 to release another work-piece from a hopper 99. The ejector mechanism is brought into action by the operation of a gauge consisting of a diamond or other point 113 carried by an arm 112 on a shaft 111, which is rotatably urged by a spring, a plunger, and rack gearing 118, the point 113 being able to move upwards to allow rotation of the shaft 111 only when the work is to size, and when such rotation takes place a switch is closed by a cam on the shaft. The shaft is carried by a housing 109 and is moved axially during removal and replacement of a work - piece by mechanism acting in timed relation to the operation of the ejector ; motion of the shaft 90 is produced by a piston 102 in a cylinder 103. Adjustment of the work and movement thereof to compensate for wear of the grinding-wheel may be effected manually by means of a screw 168 engaging a nut 169 carrying the follower 48, and may also be effected automatically, through gearing 178, 177, 182, 183, 185 and adjustable ratchet gearing, by movement of a piston 131 which moves the cam 47. The movements of the work &c. are controlled by valves actuated by solenoids the circuits of which are closed by switches actuated by the movements of the parts, and the cycle of operations of the machine is as follows. The grinding-wheel table 33 is put into reciprocation by movement of a handle 40 and continues the reciprocation by the action of dogs 42 which move the handle at the ends of the strokes of the table. A work-piece 44 is placed on the rest 74 and pressed by the roller 75 against the regulating-wheel 56, and also, by the inclination of the roller axis, against a stop 80a. A handle 195 is then moved to cause the carriage 43 to move towards the grinding-wheel, and when the work is in grinding position, a dog 126 contacts with a rock arm 124 to stop that movement by the opening, through a link 125, of a switch in the circuit of the solenoid of the appropriate valve. Another switch is simultaneously closed, and through its solenoid causes movement of the workcarriage until the work is ground to size. The gauge then moves and initiates the retraction of the work, removal of the gauge from operative position, ejection of the work, and replacement thereof, when the cycle commences again. The work is cooled by fluid supplied from a pipe containing a valve operated by a stem only to supply fluid during actual grinding operations. Specification 357,622 is referred to.