Patent GB-722269-A (GB)
Title: Vehicle drive mechanism
IPC: B60K17/35
Filed: 1951-12-04
Abstract: 722,269. Free wheel clutches. TIMKENDETROIT AXLE CO. Dec. 4, 1951 [Dec. 21, 1950], No. 28384/51. Class 80 (2) [Also in Group XXXI] Relates to front and rear wheel drives for a vehicle (see Group XXXI) in which the front wheel drive includes an over-running clutch and is at a lower angular velocity than that of the rear wheels. As shown in Figs. 1 and 2, the vehicle comprises front and rear axles 46, 56 driven from an engine 20 through a clutch, change speed gear 24, a universally jointed shaft 30, a transfer gear case 38 containing a reversing mechanism, universally jointed shafts 48, 58 and differentials 44, 54. The input shaft 36 of the transfer gear 'is splined at 88 and carries thereon a clutch element 94 adapted to be engaged with clutch elements 100, 102 on gear wheels 76, 82 rotatably mounted on the shaft 36, movement of the element 94 being controlled through a rod 106. The shaft 36 carries a clutch element 122 adapted to be engaged by another element 132 slidably mounted on a power take off shaft 126; the shaft 126 may drive a further axle and carries an eccentric 136 to operate an oil pump 139 to lubricate bearings 130, 128. The gears 76, 82 are permanently in mesh with gears 156, 158 mounted on a shaft 144. The shaft' 144 carries a gear 162 in mesh with a gear 196 rotably mounted on a shaft 40 which is connected to 'the shaft 48. The shaft 40 carried oppositely arranged unidirectional drive sprag clutches 200, 202 such as described in U.S.A. Specification 2,407,772, the outer races of the clutches carrying teeth adapted to be alternatively engaged by teeth 207 on a clutch sleeve 204 having teeth 205 engaged with teeth 206 on the gear wheel 196. The shaft 40 is carried at one end in a shaft 42 to which is keyed a gear wheel 172 meshing with the gear 158. The part of the universal joint 62 carried by the shaft 42 carries a brake drum 178. The arrangement of the transfer gearing is such that there is a slightly greater speed reduction ratio between the gears 162, 196 than between the gears 158, 172 so that the shaft 48 has an angular velocity slightly less than that of the shaft 58, so that, assuming the sleeve 204 is engaged with the forward drive clutch 200, and the vehicle is driven forwardly, only the wheels 66 ot the rear axle are driven unless such wheels slip when the drive is transmitted to the wheels 64 through the clutch 200. The sleeve 204 is moved to engage either clutch 200, 202 or to engage neither, either manually or, as shown in Fig. 6 under the control of the change speed gear lever. The low and reverse shift rail 344 has a pin and slot engagement with a pivoted arm 340 which is connected by a clevis 338 to a rod 327. Arranged between stops 334, 331 on the rod 327 are springs 329, 332, and between the springs an arm 325 is slidably mounted on the rod 327. The arm is carried on a shaft 213 carrying a fork 210 engaging the clutch sleeve, a spring 216 urging the sleeve into its forward drive position, the springs 329, 332 permitting synchronization of the clutches. As shown in Fig. 6, the rearward drive clutch 202 is omitted and replaced by teeth 328 on the front axle output shaft 310, the teeth 328 being connectable with teeth 330 on the rear axle output shaft 302 by means of a toothed ring 322 carried by the clutch sleeve 318. In a further modification, Fig. 8, the front axle output shaft 400 is connected to the gear 402 meshing with the gear 162 by a sprag-type over-running clutch 408 which is constructed so that the gear 402 can impart only forward drive to the shaft 400. The shaft 400 has keyed thereto a toothed ring 410, the teeth of which can be connected for rearward drive with teeth 420 on the gear 402 by means of a sleeve 418 which is controlled by similar means to that shown in Fig. 6, the sleeve 418 being shown in its forward drive position. In another embodiment, Fig. 11 (not shown), the angular velocity of the front wheel drive is arranged to be slower than that of the rear wheels by suitable proportioning of the gearing in the differential gears instead of proportioning the gearing within the transfer case, the gearing 162, 196 in Fig. 1 being omitted. With this embodiment the front axle output shaft is driven from the rear axle output shaft either through oppositely arranged over-running sprag clutches, Fig. 12 (not shown), or through a forward over-running clutch and a rearward direct clutch, Fig. 13 (not shown). U.S.A. Specification 1,738,212 also is referred to.