GB245478A - Improvements in vacuum brakes - Google Patents

Abstract

245,478. Dewandre, A. July 5, 1924. Addition to 226,670. Fluid-pressure; hand and foot action; force-transmitting mechanism. - In vacuum brakes for vehicles fitted with internal-combustion engines and of the kind described in the parent Specification, means are provided whereby, as in Specification 232,738. the braking effort exerted by the cylinder piston reacts upon the operating-pedal; whilst the control of the distributor is effected from the pedal through a system of rods and levers in such a manner that the distributor, after being moved to. one or other of its operative positions, is automatically returned to neutral position by the subsequent movement of the brake rigging. In the form shown in Fig. 1, the piston rod of the brake cylinder 8 is connected through members 11 - - 15 to a lever 16 mounted on a pin 17 carried by one of two levers 18 rigid with a rock-shaft 19, connections 20, 21 leading to the blakes being provided on the levers 18. Rods 24, 25 connect the lower ends of the levers 16, 18 to a lever 23 keyed on the pedal shaft, the rod 24 being pivoted directly on a pin 28 carried by the lever 23, and the head of the rod 25 being provided with an elongated slot 26, Fig. 3, a regulating screw 40 in which is normally engaged by the pin 28. Freely mounted on a cylindrical extension of the head of the rod 25 is an arm 33, a slot 36 in which is engaged by a square boss 35 on a pin 34 carried by the lever 23, and the upper end of which is connected by the rods and levers shown to the distributor 4, which is connected by pipes 2, 9 respectively to the suction pipe of the engine and the brake cylinder. With this arrangement, the initial movement of the pedal 22 rocks the lever 23 without moving the rod 25, as the pin 28 moves rearwardly in the slot 26. The arm 33, however, is at once rocked by the pin 34 to operate the distributor, and when the brakes are thus applied, the braking effort transmitted to the lever 16 reacts through the rod 24 and lever 23 on the brake pedal. The movement of the lever 18 will so move the rod 25 as to rock the lever 33 about the pin 34, now stationary, to return the distributor to neutral position, unless the pedal is further depressed. If the movement of the pedal is such that the pin 28 moves to the rear of the slot 26, the brakes will be applied also bv foot pressure. In a modification, Fig. 5, the cable 11 from the brake piston acts on a lever 40 pivoted on a lever 41 connected at 45 to the brakes, and the braking pressure reacts on an extension 42 of the pedal 44 by means of the upper end of the lever 40. In this arrangement, the distributor is operated by a rod 49 acting on a lever 46 pivoting about a pin 52 carried by a lever 47 connected to the lever 41, the lever 47 being operated by the pedal only when a pin 50 carried by it is engaged by the rear end of a slot 51 in the lever 46.