GB977137A - Apparatus for reproducing mechanical movements at a predetermined ratio - Google Patents

Abstract

977,137. Lirikwork; toothed gearing. HANCOCK & CO. (ENGINEERS) Ltd. Oct. 14, 1963 [Oct. 12, 1962], No. 38734/62. Headings F2K and F2Q. [Also in Divisions B3 and G3] A mechanism for linking two movable members of a machine, particularly a burner carriage 17 and a tracing carriage 22 of an oxygen jet profile-cutting machine, such that one member 17 imparts movement to the other member 22 in a predetermined relationship as to speed and displacement, comprises a crosshead 28 on the burner carriage 17 engaging an inclined slide bar 27 such that horizontal movement of the burner carriage causes a vertical movement of the crosshead in dependence upon the inclination of the slide bar, and means 34 are provided to convert this vertical movement into a movement of the tracing carriage 22. The latter is movable along the same trasverse rails 20 as the burner carriage 17 and carries an electronic tracer 40 adapted to scan a scale drawing on a table 24. The transverse rails 20 are mounted on a main carriage 18 running along longitudinal rails 20. In operation the tracer 40 scans the scale drawing on table 24 and produces electric signals corresponding to any change in direction. These signals control two motors driving the main and burner carriages thereby causing the torch 15 to cut the workpiece 14 along a profile enlarged, e.g. ten times, over the movement of the tracer 40. The crosshead 28 on burner carriage 17 has a roller 33 engaging the inclined slide bar 27. A cable 34 or steel tape anchored at 35 passes over pulleys 30, 31 on carriage 17 and around pulley 32 on the crosshead. The cable is attached at 39 to the tracing carriage 22 and is kept taut by a spring or counterweight 37. Transverse movement of the burner carriage thus produces a variable loop in the cable dependent upon the inclination of the bar 27 and this provides a reduced scale follow-up movement of the tracing carriage. The inclination of bar 27 may be varied or may be reversed so that the carriages 17, 22 then move in opposite directions. Drawing table 24 is movable longitudinally along the rails 26 and is linked to the main carriage 18 by a rack 48 meshing with a pinion 47 on the same shaft as a second pinion 46 meshing with a vertical rack 44, Fig. 2, on a vertically movable crosshead 42 of the main carriage 18. Crosshead 42 has a roller 43 running along an inclined bar 41 whereby the follow up movement of the table 24 is dependent upon the inclination of the bar 41. The rollers 33, 43 may alternatively run along the upper surfaces of their respective bars and the crossheads 28, 42 may be arranged at an angle other than vertical.