GB722201A - Improvements in or relating to parking brake actuating means for tractors and like vehicles - Google Patents

Abstract

722,201. Controlling vehicles. TWENTYMAN, C. E. H. July 10, 1953 [April 10, 1952], No. 9164/52. Class 79(5). [Also in Group XXXIV] In brake actuating means for tractors and the like where the brakes are applied and released through a pedal-operated lever which carries a pawl for engagement with a fixed rack and which is adapted to be displaced to its brakeapplying position by the driver of the vehicle and adapted to be held in that position by engagement of the pawl with the ratchet, there is secured to the lever an arm which extends therefrom to the vicinity of the driving seat so as to adapt said lever for manual operation also, and there is located on said arm, adjacent the driver, an auxiliary lever which, when swung into one of two extreme positions, operates through a linkage system and a cam positively to retain and lock the pawl in engagement with the ratchet. Fig. 1 illustrates the brake operating lever 1 in its inoperative or " off " position. The lever 1 is provided with a laterally projecting pedal 3 which when depressed actuates the lever 1 about its pivot 2 to apply the brakes. The lever 1 may also be actuated by depressing the arm or hand lever 8. Having applied the brakes, the driver may take the pawl 6 into engagement with the fixed ratchet plate 4 to retain the lever 1 in the " on" position either temporarily by depressing the spring-loaded plunger 13 by hand or permanently by swinging the auxiliary lever 19 from the idle to the working position. The action of the auxiliary lever 19 is shown in enlarged scale in Fig. 3 ; so that when the lever 19 is moved to the locking position, illustrated in full lines, a cam-like projection 20 is moved to strike and ride along the rounded shoulder 21 on the upper edge of a rocket member 16 and causes the rocker to turn in the direction which depresses both rods 15 and 17. The depression of the rod 15 pulls down the plunger 13 whereas the depression of the rod 17 turns the cam 18 about its pivot to engage the pawl 6 with teeth 7 of the ratchet plate 4. When it is desired to release the brake, the auxiliary lever 19 must be swung to the position shown by the chaindotted lines in Fig. 3 and a slight depression given to the lever 1 will enable the pawl 6 to assume the vertical position shown in Fig. 1 and release the brake operating lever 1.