| 摘要 |
1,194,092. Machine tool details; drilling. FERRANTI Ltd. 23 Dec., 1968 [13 Jan., 1968], No. 2028/68. Headings B3B and B3C. [Also in Division F2] Means for producing relative movement between two bodies comprises a main toothed rack F attached to one of the two bodies and at least three actuators A, B, C attached to the other body, each actuator being operable to force into engagement with the rack F a stub toothed rack E of the same tooth pitch as the main rack F, the stub racks being spaced from one another by a distance differing from an integral number of rack tooth pitches by a like fraction of a pitch equal to the reciprocal of the number of actuators. As shown, for three actuators A, B, C the spacing # 1 is seven plus one-third tooth pitches. Alternatively, it may be seven minus one-third tooth pitches. The actuators may be hydraulic, pneumatic or electromagnetic. In an application to a machine tool, a carriage 14 is adapted to slide on rails 11, 12 and the carriage 14 supports a further pair of rails 15, 16, arranged at right angles to the rails 11, 12, which carry a slide 17 on which is mounted a machining head 18. The slide 17 is movable by transport means comprising electromagnets 20, 21, 22 having armatures 23 which act on bell-crank levers 24 to move stub toothed racks 37 into and out of engagement with a main rack 36 carried by rail 15. Dashpots 29 and limit switches 35 are provided. Similar transport mechanism for the carriage 14 is provided comprising electromagnets 40, 41 and 42. The transport means may be controlled by punched tape or magnetic tape. |
