| 摘要 |
870,837. Lathe detaits. CRI-DAN. Nov. 11, 1958 [Dec. 20, 1957], No. 36251/58. Class 83 (3). In a screw-cutting lathe, the reciprocation of the tool-carriage 3 to bring the tool 5 into and out of engagement with the work is controlled by a cam 6 (and spring 14), engaging a roller or shoe 18 on a sliding rack 19 which meshes with teeth on a shaft 22 having further teeth 26 meshing with a second rack 28 which moves the carriage. The cam 6, Fig. 3, is oscillated by a cam 16 on the main cam-shaft 17 through a lever 11 and link 10, and is secured to an eccentric cam 7 which may be of the type disclosed in Specification 624, 612. The teeth 26 and 21, Fig. 2, have different helices so that longitudinal movement of the shaft 22 by a micrometer screw 25 produces relative movement of the rack 28 and hence sets the carriage 3 to the required depth of cut. The withdrawn position of carriage 3 is adjusted by a micrometer screw 30. The eccentric cam 7 is rigidly mounted on an eccentric 8b fixed to a shaft 8 supported in the saddle 1. A toothed wheel 8a secured to the shaft 8 is driven from the shaft 17 by known means, thus progressively rotating the cam 7 and advancing the cutting tool towards the work to increase the depth of cut. Specification 640,142 also is referred to. |
