1,195,894. Variable ratio gear. THOMAS & BETTS CO. 23 June, 1967 [23 June, 1966], No. 25340/67. Heading F2D. [Also in Division B3] A friction drive unit comprises an input shaft 16 which has keyed to it a cone 15, the face 15a of which makes an angle of 60 degrees with the shaft axis. A similar cone 17 is keyed to an output shaft 18 and is biased by a spring 19 towards the input cone. A ball 20 is rotatably mounted on a shaft 21b, Fig. 2c, which is guided for displacement, in a vertical plane passing through the axis Xa, between the limiting positions Xb-Xb and XSP11/SPb-XSP11/SPb. In the second position the axis of the shaft 21b is normal to the face 17a of the cone 17. In the first position the effective diameters DSP1/SP 3 and DSP1/SP 4 of the ball 20 in contact with the cones are equal and the speeds of the input and output shafts are equal. In the second position the speed of the output shaft is zero. The end 21c of the shaft 21b is displaced by a cam C which is shaped so that equal increments of angular motion of the control D give equal increment of speed of the output shaft 18.
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