GB1119899A - Automatic lapping machine - Google Patents

Abstract

1,119,899. Grinding. R. S. GENTRY. 14 Nov., 1966 [25 Feb., 1966], No. 50936/66. Heading B3D. An automatic lapping machine comprises a base 10, a worktable 12 supported on the base, a plurality of post members 16 slidable vertically in guides 14 through the plane of the table, a head 20 mounted on the upper ends of the post members, a lap carrier 28 mounted for reciprocating movement in the head, drive means 36 for reciprocating the carrier and laps through upward and downward strokes of predetermined length, feed drive means 108 below the worktable for actuating a feed mechanism 82 acting on the lower ends of the posts to raise and lower the posts and head with respect to the table, means to actuate the feed drive means at a predetermined point of each downward stroke of the lap carrier to lower the head and posts by a predetermined amount, and means to arrest the downward movement of the lap carrier and lap on meeting resistance by the workpiece exceeding a predetermined amount. The posts 16 are connected at their lower ends to a platen 18 and at their upper ends to the head 20 which has a central housing 24 for slidably receiving the lap carrier 28. A yoke 38 is secured to the carrier and has an insert 40 for engaging a cam 36 rotated by a belt-drive from a motor 56. An air cylinder 44 has a rod 42 for urging the insert 40 against the cam. An extension 46 from the yoke has a bore slidable on a post 50 to guide the yoke and a screw 72 which co-operates with a limit switch S-1. A threaded bore in the lap carrier receives a holder 62 for a lap 64 which operates on the bore of a workpiece 66 secured by a clamp 70 to the worktable 12. The lower platen 18 is connected through a lost-motion connection with a lead screw 82 drivable through reduction gearing 84 from a shaft which is driven under manual control from a motor 96 when an electromagnetic brake 92 is engaged to raise or lower the head and lap. Alternatively, the shaft is rotated incrementally to effect downward feed of the head and lap when the screw 72 actuates switch S-1 to cause actuation of an air cylinder 108 which reciprocates a rack 106 engaging a pinion connected by an electromagnetic clutch 102 with the shaft. In operation, the lap and head can be vertically adjusted by operation of the motor 96, and the motor 56 energized to rotate the cam 36, the air cylinder urging the insert 40 against the cam so that the head and lap are vertically reciprocated. At each downward movement the screw 72 actuates switch S-1 so that cylinder 108 causes an increment of downward feed. If the resistance to downward movement between the lap and workpiece exceeds a predetermined amount and the head and lap do not follow the movement of the cam the switch is not actuated until the resistance to downward movement caused by lapping has decreased. The lapping continues until a switch S-5 in the head is actuated by a rod 78 on the table 12.