Patent GB-646517-A (GB)
Title: Improvements in or relating to machines for manufacturing screw sticks
IPC: B23G1/02
Filed: 1948-02-26
Abstract: 646,517. Turning ; rolling screw-threads ; axial rolling. KODAK, Ltd. Feb. 26, 1948, No. 5864. Convention date, March 11, 1947. [Classes 83 (iii) and 83 (iv)] A machine for forming, threading and cutting off a screw stick S, Fig. 9, in the form of a predetermined number of finished. screws comprises a stock-holding chuck 3, Fig. 2, an intermittent stock-advancing mechanism (not shown), movably-mounted forming, threading, and cut-off tools 5, 9 and 7, actuated from a mechanism including a cam-shaft 19, Fig. 1, and two cam followers 14, 57, means for displacing a cam 12 to operate either of the followers 14, 57, and control means whereby the forming and threading tools are actuated a predetermined number of times for each actuation of the cut-off tool. The cam-shaft 19 carrying the cam 12 is rotated in timed relation with a shaft carrying a cam 73, Fig. 10, which advance: a slide 11 disposed parallel with the chuck spindle 2 and supporting a turret 10 adapted to carry the threading tool 9 comprising threading rolls 74, 75, Fig. 7. The latter are mounted on bell-crank levers 76, 77 which are pivoted at 78, 79 and geared together at 80, 81 so as tc engage the part to be threaded when a screw 83 in a projection 82 of the lever 77 is engaged by a bar 84, Fig. 2, secured to a slide 6 for the forming tool 5. A slide 8 for the cut-off tool 7, and the slide 6 are actuated through rock gears 17 on bell-crank levers 15, the lever for the slide 8 being operated through a pivotedlever carrying the follower 57. During each rotation of the cam-shaft 19 and a continuation-shaft 23, which is connected thereto and carries cams 41 and 26, the cam 12 advances the slide 6 to bring the forming tool 5 into engagement with the stock 5 to form the shank E and a narrow neck N between the shank and the adjacent head H, after which the slide 6 withdraws and the threading rolls 75, 76 are advanced by the cam 73 and caused to engage the stock by co-operation between the bar 84 and screw 83 effected by the cam 12 again advancing the slide 6. The mechanism for controlling the number of operations of the forming and threading tools for each operation of the cut-off tool 7 is operated after each forming operation when the cam 26 moves a slide 30 against a spring 32 so as to cause a spring-loaded catch 33 on the slide to advance a counting wheel 34 through one tooth, the wheel then being locked by a spring-ratchet 38. After the wheel 34 has completed one rotation (i.e. when the screws formed on the stick equal in number the teeth on the wheel), a spring- loaded pin 59 trips a lever 48 away from a latch 47 on a rod 44 so as to cause the rod and a dog 52 thereon to move axially under the influence of a spring 51. The latter movement influences the dog 52 to move the cam 12 into a position beneath the follower 57 for operating the cut-off tool 7. After the cut-off operation, the rod 44 is returned to the screw-forming position by the cam 41 actuating a follower 43, the rod 44 tripping the lever 48 against the spring 50 into a position behind the latch 47. Specification 548,605 is referred to.