GB291942A - Improvements in differential mechanism - Google Patents

Abstract

291,942. Lewis, F. M. May 23, 1927. Differential gearing comprises two positive clutches which normally drive so that either is disengaged automatically to allow over-running, and means to disengage either or both of the clutches manually. The application to a tractor is described. A master wheel 33, Fig. 1, driven as shown in Fig. 10, carries fixedly a spider comprising radial cam arms 42 united at the centre in a floating ring 40. Fig. 2. The wheel 33 is carried on a loose revoluble casing 29 which embraces and supports clutch members 36, 37 fast on axle parts 24, 25, which may be medially supported on a thrust ball 39. The members 36, 37 may be the side gears of the usual differential. The driving clutch members are floating rings 44. 45 which have cam recesses 46 by which they are drivingly thrust 'apart by the driving spider arms 42. The face teeth of the rings 44, 45 are so angled that when a driven member 36 or 37 over-runs, the driving ring is cammed inwards out of engagement against springs 49, Fig. 2, while a pin-and-slot 50<a>, Fig. 5, prevents the opposite cam face 47 of recess 46 from becoming operative. Such opposite faces are operative for reversed driving. There is less lost motion than in the arrangement described in Specification 261,146. Manual disengagement is effected by two spring-separated thrust spiders 52, Figs. 1, 5, and 8. These have dogs 54 which engage shoulders 56 on the driving-rings 44, 45 and operate to thrust the ring positively out of engagement, as shown in F'ig. 5, in case of ring 44. This axial thrust is generated by the turning of two cam rings 64, Figs. 1, 5 and 9, relatively to fixed cam rings 61. This has been done by a pull in a rod 69, Fig. 5, exerted against a spring 71. In Fig. 13 is shown means by which the tractor when, say, ploughing, may be turned sharply round on one disconnected wheel as pivot. Steering shaft 83 has been turned to the left so that clutch rod 69 on the left is pulled, disconnecting the left wheel, while the right wheel keeps on driving. The single wheel which is driven may be raised off the ground and used as n power take-off, in which there is not the doubling of speed which the usual differential gear yields. Both ground wheels may be simultaneously disconnected and power may then be readily taken off from a pulley 77, Fig. 10, on an extension of the propeller shaft 35, which is driven through a change-speed gear. An arrangement with two hand-levers for disengaging the driving-clutch rings independently for this purpose is described.