Patent GB-323048-A (GB)
Title: Improvements in or relating to clutch mechanism
IPC: B60K17/00
Filed: 1928-08-24
Abstract: 323,048. Humfrey, J. C. W., and Humfrey-Sandberg Co., Ltd. Aug. 24, 1928. Clutches, claw and ratchet; facilitating changing speed.-In mechanism comprising a positive clutch combined in parallel with a unidirectional clutch of the kind involving axial or other relative motion between the driving and driven members to bring about engagement, this relative motion is positively effected by a stop member, which is in slipping-engagement with the unidirectionalclutch driving-member and has limited rotational freedom relative to a driven part of the mechanism, the limited rotation serying to release the positive clutch for engagement only on synchronism between the driving and driven members and being necessarily accompanied by the movement effecting engagement of the unidirectional clutch. The unidirectional clutch may, as shown in Fig. 1, be of the type described in Specifications 239,894, 248,183, and 286,389, comprising outer and inner conoids 9, 15 with interposed skewed rollers (not shown). The outer conoid 9 is pressed towards its disengaged position by springs 11 and has sliding engagement with teeth 2 on a drum 1 secured to a driving-shaft 4, which may be the tail-shaft of a motor-vehicle gear-box. The member 1 forms also the driving-member of the positive clutch, being engageable by a toothed driven member 5 pressed by springs 30 and slidable on the propeller shaft 6, to which the inner conoid 15 is rigidly fixed. Rollers or balls 25 are interposed between an abutment 19 and inclined surfaces 22 on the stop member 18, which frictionally engages the conoid 9 by a plane or conical face 21 and carries three pins 27 passing through slots 28 in the member 5. Alternatively, the member 19 may have inclines coacting with the inclines 22, and the pins 27 and slots 28 may be interchanged. To avoid jamming, the inclination of the surfaces 22 must substantially equal the angle which the axis of each skewed roller of the one-way clutch makes with the shaft axis when viewed along a line normal to both axes. When, by a fork 8 engaging a collar 7, the member 5 is withdrawn, as shown, and the shaft 6 overruns the shaft 4, the stop member 18 is moved by the conoid 9 in a combined rotary and axial direction, so carrying the pins 27 to the ends of the slots 28, where, as shown in Fig. 2, shoulders 29 prevent re-engagement of the clutch 1, 5 until the part 1 overtakes the shaft 6, the member 18 being then frictionally advanced by the conoid 9 and simultaneously, by the action of the parts 22, 25, causing reengagement of the skewed-roller clutch. In a modification, Fig. 3 (not shown), the skewed-roller clutch is replaced by a friction plate slidable on the shaft 6 and adapted to be gripped between the plane or conical surface 21 of member 18 and the end wall of drum 1 by the action of the parts 22, 25 or of the modified means described with reference to Fig. 1. In another form, the member 18, Fig. 4, carries a coned rim 45, coacting with a female cone 46 on the conoid 9, and has a boss 64, shown developed in Fig. 5, with inclined projections 35, flat faces 38, and slots 37, the abutment ring 19 having shorter inclined projections 40, recesses 44, and apertures 42 for pins 43 carried by the clutch member 5. As the torque transmissible through the cones 45, 46 exceeds the frictional resistance of the coacting projections 35, 40, the device functions similarly to the form shown in Fig. 1. The driving and driven shafts 49, 6 are journaled in a casing 47, the shaft 49 being coupled to the gear-box tail-shaft by a universal joint, partly shown at 51. The cone 45 may be replaced by radially spring-pressed segments, Figs. 6 and 6a (not shown), coacting with a rim on the conoid 9. The arrangement shown in Fig. 5, or a modification thereof employing interposed balls rolling on a flat face of the part 19, may be used with the clutch shown in Fig. 1.