GB743551A - An improved thread milling machine - Google Patents

Abstract

743,551. Screw-thread milling. PASS & CO., Ltd., E. June 17, 1954 [June 17, 1953], No. 16654/53. Class 83 (3). [Also in Group XXIII] A screw-thread milling machine comprises a carrier ring 10 to be secured on the outside of a pipe 14, a tool housing rotatable by a worm drive 16, 18 on the carrier, a drive connection 32 for a cutter 30 adjustable in the housing, and disengageable screw-and-nut means 33, 35 to enable the housing to be fed axially as it is rotated on the carrier. In operation, the carrier is clamped by a split collet 12 to the pipe 14 to be threaded. The tool carrier 24 is then fed manually by screw 25 until a cutter 31, rotated by the shaft 32, pierces the end of the pipe. A plunger 39 locking the housing 11 to the screw-threaded ring 35 is then withdrawn, the screw rings 33, 35 are locked by a grub-screw .(not shown), and the housing 11 is rotated on the carrier by the worm gearing 16, 18. When the end of the pipe has been trimmed, the cutter 30 is fed by the screw 25 to a depth indicated by means 27. The locking-plunger 39 is then engaged and the screw-and-nut 33, 35 freed relatively to one another. Rotation of the worm gearing 16, 18 now causes an axial feed movement of the housing 11 as it rotates, the cutter 30 thus cutting a thread on the pipe. In a modification, a simple disengagement of the nut and screw 33, 35 may be provided.