Patent GB-257279-A (GB)
Title: Improvements relating to track braking apparatus for railway and the like vehicles
IPC: B61K7/12
Filed: 1926-08-20
Abstract: 257,279. Westinghouse, Brake & Saxby Signal Co., Ltd., (Assignees of Coleman, J. P.). Aug, 21, 1925, [Convention date]. Arresting-grips on permanent way; electric.-In track braking apparatus for railways &c., comprising braking elements adapted to be moved into engagement. with the wheels &c. of a vehicle by the action of an electric motor, the supply of current to the motor is automatically controlled, in accordance with the setting of a control lever. As shown, the braking apparatus comprises bars 2. 3 arranged one on each side of a rail 1 and connected by springs 6 to bars 4, 5 connected by links 7<a> to a lever 7 pivoted at 27 and connected to an arm 26 forming an extension of a toothed sector 24 pivoted at 25, clockwise movement of the sector applying the brake bars to the wheels of a vehicle. The sector 24 is geared by a. pinion and toothed wheel to a worm 20 loose on a spindle 16 and provided with a clutch part 21 adapted to co-operate with a clutch part 17 fast on the spindle which is operatively connected to the shaft of the rotary armature 10 of an electric motor comprising a field structure A<1>, spaced pole pieces 9, 9<a>, and a field winding 8. When the winding 8 is energized by current from a battery C, an armature 13 on a lever 12, pivoted to a bracket 11 on the motor, is attracted to the pole pieces against the action of a spring 53, closes contacts 14, 15 supplying current to the armature, and, by connection to a sleeve 17<a> on the spindle 16, causes the clutch parts 17, 21 to engage so that the worm is rotated and the brake bars applied. Hand control levers 33, 34 in the battery and field-winding circuit are connected by an insulating handle 35 and are adapted to make contact respectively with contacts 36 - - 39 and 40. 41. The contacts 37 - - 40 are electrically connected to contact pieces 29 - - 32 of different lengths and arranged as shown to co-operate with a control lever 28 operatively connected to the sector arm 26 and electrically connected to one end of the winding 8, of which the other end is connected to the contacts 41, 36. In the brake-off position shown, the lever 28 engages the contacts 29 - - 31, and the levers 33, 34 engage the contacts 36, 40, all circuits being broken. When the levers 33, 34 are moved so that the lever engages one of the contacts 37 - - 39 and the lever 34 engages the contact 41, the field-winding circuit is closed through one of the contacts 29 - - 31, and the motor commences to operate to move the sector 24 and apply the brakes and also to move the lever 28 over the contacts 29 - - 31, the length of the operative contact determining the time dur. ing which the motor acts and therefore the preasure applied by the brakes. When the lever 28 has moved off the operative contact, the circuit is broken; but the lever has engaged the contact 32. so that return of the levers 33, 34 to their initial positions closes a reverse circuit through the field winding 8 and the motor operates to release the brakes until the lever 28 leaves the contact 32.