Improvements in generating and measuring involute or modified involute surfaces

摘要

722,011. Gauging toothed gears. MAXWELL, D. C., and PARSONS & MARINE ENGINEERING TURBINE RESEARCH & DEVELOPMENT ASSOCIATION. July 4, 1952 [July 16, 1951], No. 16787/51. Class 106 (2). [Also in Group XXII] Means for guiding a contact piece 10a of a measuring instrument to envelope a circular involute comprises a kinematically inverted cycloidal slider crank mechanism, Fig. 2, so mounted on a radius arm 1, Fig. 4, pivoted about a fixed centre 2, that the coupling link CL of the mechanism is the stationary member relative to the arm. A second arm 12 for actuating the arm 1 is connected thereto by a link 3 pivoted to the arms at 5 and A1, the lines joining pivots 2 and 5 and A1 and the fixed pivot 13 being equal and parallel. Fixed to the link 3 is an arcuate element CD supporting, by tapes 8, a straight-edge 7 passing through the axis of the pivot 5. The straight-edge 7 carries a slotted plate 9 in which is guided a block 10b on the element 10. It is shown in the Specification that the element 10 envelopes a true involute originating at the centre of the pivot 2. If the pivot 13 is movable, the involute may be modified to provide or measure tip or root relief on a gear-wheel. In a modification, the straight-edge 7 lies below the axis of the pivot 5 and the element 10 projects beyond the generating mechanism. In a further modification, the element 10, Fig. 7, is mounted for sliding movement relative to the arm 1 by means of pins 15 and a.guide 16. In a final modification, the element 10, Fig. 8, is made in two relatively movable parts so that the lower part 30 may be displaced to record deviations from a true involute on a dial gauge 19. Specification 691,734 is referred to.