GB468652A - Improved mechanism for transforming reciprocating movement into rotary movement, and conversely - Google Patents

Abstract

468,652. Gearing for converting rotary into reciprocating motion and vice versa. VARCIN, A. L. April 1, 1936, No. 9700. Convention date, April 2, 1935. [Class 80 (i)] In the mechanism described in Specification 270,562, [Class 80 (i)], the cams for facilitating reversal at the ends of the stroke are so shaped that the last tooth of the mutilated pinion 7 to engage a rack 1 comes out of contact with the corresponding tooth of the rack before sliding begins. As shown in Fig. 2, the profile 17 of the cam lies between the archimedean spiral, eghg<1>e<1> which would produce the same movement of the rack as would be produced by a continuously - toothed pinion and the curve egig<1>e<1> which would produce the same movement of the rack as would be produced by the last tooth p<1> if it slid off the last tooth c<1> of the racks. As shown at p<3>, c<30>. The portions eg, g<1>e<1> of the profile 17 belong to the spiral, since up to the position p<2>, c<2>, the gear engagement is perfect. If gear engagement continued, the rack tooth would reach c<6>, but the cam portion g j brings it to an intermediate position c<3> in which it clears the pinion tooth at p<3>. The part j, f, j<1> of the cam is designed to produce a constant acceleration, or may be of sinusoidal form to give zero acceleration at dead centre, or the cam may produce zero, constant and variable accelerations at different parts of its stroke. The cam may be unsymmetrical about OX. The invention is applicable to the form disclosed in Fig. 3 of Specification 270,562, in which two pinions are employed. The end teeth of the pinion may be bevelled as shown at t so that a flatter curve egkg<1>e<1> may be employed. The invention may be applied to engines, the piston or pistons being secured to the racks.