Patent GB-526783-A (GB)
Title: Improvements in or relating to unidirectional coupling devices
IPC: F16D41/06
Filed: 1939-04-28
Abstract: 526,783. Ratchet gearing. ROBIN, L., and ROGGEN, M. VAN. April 28, 1939, Nos. 12825 and 12826. Convention dates, April 29, 1938, and Dec. 13, 1938. [Classes 80 (ii) and 80 (iii)] Relates to unidirectional rotary driving devices, e.g., of the kind described in Specification 473,040 where two surfaces, driving and driven, are adapted by a gear connection to roll one with respect to the other when relative movement takes place between them, an obstacle between the surfaces being adapted to wedge them for one only of the directions of rolling. According to the invention, the obstacle and the surfaces with which it co-operates are so shaped that this obstacle can exert a wedging action in planes different from the planes of instantaneous rolling movement of the two surfaces. An oscillating arm 11, Figs. 1, 2, is integral with an eccentric 8 which is rotatable over sleeve portions 9 splined to a driven shaft 3 and integral with plates 5 having an inner surface 1 concentric with the centre 0<1> of the driven shaft 3. The outer surface 2 of a sleeve 10 mounted on the eccentric 8 is caused to roll with respect to surface 1 by gears 6, 7. At least one obstacle or wedge C is inserted between the surfaces 1, 2. The driving and driven parts may be interchanged and the friction surfaces may be duplicated. In order to obtain a suitable wedging angle when driving in the direction E, Fig. 1, and a suitable release in the direction R, the wedging effect is increased by giving the wedge C an angularity # Fig. 4, in radial planes. This additional angularity may be applied to both rolling surfaces or only to one of them. Thus the wedges C, flattened in the direction of the rolling movement, have at least one projection 12 with chamfered sides 13, 14, of the same or of different inclinations, adapted to coact with corresponding grooves 15 in the surfaces 1, 2. The grooves may be in the wedges and the projections on the surfaces. Each wedge may have several grooves or projections. The angle # between the chamfered sides may be of the order of 40 degrees or 60 degrees and of itself produces no wedging effect. These chamfered sides may be provided on rollers 17, Fig. 6, carried by a cage 18. The obstacle or wedge C may be maintained in position by a spring 19 having a support or axis 20 rigid with the arm 11. The Specification discusses the values of the angle a Fig. 1, between tangents T<1>, T<2> to the opposed surfaces of the wedge particularly at the middle thereof, and angle # and points out that whereas neither angle is of a wedging value, a wedging action is obtained for the driving direction E. The wedge may be recessed at its middle portion, as at 50. Fig. 19, to reduce the mean wedging angle. In the modification shown in Figs. 15, 16 the eccentric 8 is carried by the plate 5 and is on the outside of the ring 10. The member 4 of Fig. 1 is replaced by a sleeve 4<1>, on a sleeve 9 splined on the shaft 3, and to which the drive is applied, but the drive may be applied to the plate 5, the sleeve 4<1> being connected to the driven shaft. Ball bearings may be provided between the ring 10 and eccentric 8 and also between other rotating surfaces.