GB499320A - Means for preventing the rearward motion of a motor road vehicle - Google Patents

Abstract

499,320. Preventing reverse movement. MADDEN, W. R. C. July 21, 1937, No. 20233. [Class 103 (i)] In ratchet - and - pawl mechanism for preventing rearward movement of a motor vehicle, of the kind in which the pawl is disengaged upon forward movement of the vehicle by a stream of oil due to rotaton of the ratchet wheel, the mechanism is located in the gear box and the pawl is below the level of the oil and is subject to the surge thereof effected by the rotation of the wheel. In the Figure, the ratchet wheel 3 mounted on the drive shaft 2 in the gear box 1 is adapted to be engaged by the pawl 4 under the influence of a counterweight 7 when the movement of the vehicle tends to reverse. The pawl is held out of engagement by the flow of the oil impinging upon it during forward movement. This flow may be assisted or directed by a plate 8 and by vanes 9 on the wheel and the pawl may have wings extending from one or both sides. The ratchet teeth may be replaced by a circumferential series of pins extending normally to the face of the wheel and these pins may be mounted on one face of the final drive pinion of the gear box. The pawl may be disengaged when the gear is put into reverse by a rod 12 having a pin engaging a fixed cam slot 15 so that it moves downwardly when it is turned by a longitudinally sliding horizontal rod 17 which engages an arm 13 on the rod 12 and is operated by the gear lever 20. In a modification, a spindle has an arm engaging the pawl lug 11 and an external arm linked to one arm of a lever mounted on the top of the gear box, the other arm being engaged by the gear lever 20.