Patent GB-579349-A (GB)
Title: Improvements relating to inertia operated devices for speed control of vehicles
IPC: B60T8/74
Filed: 1944-03-09
Abstract: 579,349. Brakes. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. (Westinghouse Air Brake Co.). March 9, 1944, No. 4391. [Class 103 (i)] [Also in Groups XXVI and XXXV] In a speed control system for vehicles wherein the control is effected by a rotary inertia ring or wheel supported from a driving shaft or axle by radially arranged leaf-springs, means are provided for supporting the ring positively at all times when the control of the device is not required, thus relieving stresses in the leafsprings. As shown, the invention is applied to a braking-system, the annular inertia member 112 of the control device 25 being supported by leaf-springs 113 secured by embedding in solder in the centre of a spider 111, the springs 113 lying between the arms of the spider. The outer ends of the springs slide in radial slots in cylindrical members 119 housed in recesses in the member 112 and retained therein by snap rings. Limited rotation of the member 112 relatively to the spider is thus permitted, and excessive axial movement of the member 112 is prevented during the operation of the inertia device by mounting the member between a flange 134 on the spider and a disc 125 which is itself axially movable to lock the member 112 to the spider except when a brake application is made. The downward movement of the disc 125 is effected by fluid pressure on the piston 193 which depresses studs 128 against the returning springs 126. When the disc 125 is moved to lock the member 112, the latter is restored to its normal central position by the action of balls housed in grooves and recessed in the opposed faces of the disc 125 and member 112. The spider and member 112 are driven through friction cone gears 84, 87 from the axle 83, a flexible coupling 101 being interposed between a square-ended drive member 105 and the shaft 93. The gear 87 is driven by clutch fingers 97, on a sleeve press-fitted on the shaft 93, engaging openings 98 in the gear. A spring 99 urges the gear 87 into contact with the gear 84. A lever 148 is pivoted on a stud 147 on the spider 111 and is slotted to engage a pin 151 projecting upwardly from the member 112. Thus, if the member 112 is displaced relatively to the spider, either by acceleration or deceleration of the corresponding wheels, the lever 148 swings on the stud 147 and, if the swing is sufficient, a member 157, Fig. 4, pivoted at 158 on a bracket 156 on the end of the lever 148, makes electrical contact simultaneously between co-axial members 164, 165. This occurs when the deceleration or acceleration of the wheels reaches a predetermined value. In operation, actuation of the brake valve 17 admits pressure fluid to the brake cylinders 18, to the pressure switch 21 and to the top of the piston 193 to free the inertia element 112. The contact 157 is spaced from the members 164, 165 as shown diagrammatically in Fig. 1. If a slipping condition of any of the wheels 13 occurs, the excessive deceleration will move the corresponding member 157 to bridge the members 164, 165 and energise the magnet valve 48, this resulting, as described below, in venting the brake cylinder. The pressure fluid is, when the magnet valve is de-energized, admitted from the passage 15c, Fig. 2, to the underside of the piston 34, and through the. passages 15f, 15g, to the upper side thereof. The spring 37 in these conditions, keeps the vent 39 closed and pressure passes through the passages 15d, 15j, throttle 63, 15e to the brake cylinder pipe 15b. Pressure above and below the diaphragm 57 are balanced and the spring 62 keeps the valve 58 open. If wheel slip occurs, the magnet valve 48 is energized and the double beat valve 45 is moved down, and the space 42 is vented through passages 15g, 53. The piston 34 thus rises and opens the vent 39 to the passage 15d to allow the brake cylinder to vent past the valve 58, while it is open, and past the ball valve 65 when the valve 58 closes due to pressure in the space 56. The wheels now accelerate quickly to a speed corresponding to vehicle speed, and during the acceleration the contact 157 swings over and maintains the magnet valve in operation. When acceleration is ending, the contact 157 swings free of the members 164, 165 and the magnet valve is de-energized, restoring conditions for a re-application of the brakes, which, however, is effected gradually in the initial stages in virtue of the throttle 63. When the valve 58 re-opens the full pressure is rapidly applied to the brake cylinders.