GB591789A - Improvements in and relating to a thread rolling machine - Google Patents

Abstract

591,789. Rolling screw threads. REED, A. B. Oct. 13, 1944, No. 19806. Addition to 590,075. [Class 83 (iv)] In a thread-rolling machine in which the work blank is held axially immovable between and rotated by driven die rolls while the entire thread length is rolled, the rolls being moved progressively and equally through a cycle to and from the work axis, the power mechanism includes a replaceable cam which causes the dies to penetrate the work progressively during more than one die revolution in a cycle of approach, penetration and release. As shown, the work blank 10 has threads rolled in its surface by parallel or tilted dies 11, 12, 13, Fig. 2, each mounted on an arbor 14, Fig. 1, carried by the spaced arms 15, 16 of a yoke 17 which interfits with a pivot block 20 mating with a block 22 ; the arbors are guided by pivoted links 24. The blocks 22 are secured to stress rings 32, 33, carried by a supporting ring 34 which is oscillated to effect radial movement of the dies to and from the work by means of a replaceable cam 40 engaging a roller 46 carried between spring-influenced levers 47 connected by a link 50 to a block 52 on the ring 34. The stress rings 32, 33 have three cam faces 110 to which the blocks 22 can be clamped in adjusted positions and one of the rings may be turned relatively to the other, by means of a hand-operated pinion 112, to tilt the blocks for rolling tapered threads. The means for securing the blocks to the rings, and the rings to each other, consist of lugs 120 on the blocks and a draw bolt 121 pivoted thereto and passing outwards to the outer ring 34 to which it is secured by a screw 122. Each block is furnished with grooves in which metal strips 124 are seated, the strips bearing against the cam faces 110. The driving gear comprises a main shaft 63 on which are two gears driving horizontal shafts 67, 71 through replaceable gears 65, 66, 70. The shaft 67 drives the cam 40 through reduction gear 68, 69 and a clutch 43, 45, and the dies are driven from the shaft 71 through reducing gear 73, 74, pinions 76, 78 and universal couplings 80 ... 83. For small work one of the dies is replaced by a support, the other two dies being disposed at an angle of 120-180 degrees. In a further modification, only one die is moved to and from the centre.