Patent GB-162617-A (GB)
IPC: B60T7/12
Abstract: 162,617. Rodolausse, E. April 27, 1920, [Convention date]. Fluid - pressure. - T h e brake valve is opened if the speed of the train exceeds a predetermined value at any part of the track, or if, after passing a track contact at a danger signal, the speed is not reduced sufficiently. The apparatus is entirely mechanical. A cam in the form of a helical thread of variable deptb according to the allowable speed at each pcint of a journey is driven from a train-axle and moves a pointer 1 to indicate on a scale 10 the allowable speed. This pointer 1 is pivoted at 2 to a counterweighted arm 3 moved by the rod 6 and one end 19 rests on a rod 20 which operates the brake valve 22. A centrifugal governor 17 moves a pointer 12 over the scale 10 to indicate the train-speed and the end 18 of this pointer is off-set to engage the pointer 1 if the actual speed is more than the allowable speed; the pointer 1 then rocks on the pin 2 and opens the brake valve. Auxiliary pieces 11 may be attached ro the cam 9 to ensure reduction of speed at places where such precaution is temporarily required as for track repairs. The apparatus may be kept out of action at low speeds by a catch 57 on a lever 54 which prevents depression of the rod 20 until the pointer 12 is raised sufficiently to allow a spring (not shown) to remove the catch 57, which is held in action by the engagement of the pointer 12 with the free end of the lever 54. The drum of the cam 9 is notched at intervals and a pawl on a lever 34 is made to engage therewith by fixed pedals at predetermined places on the track to ensure the correct position of the cam in accordance with the distance travelled by the train. In order to impose a reduced speed at a danger signal there is provided a weighted level 49 with an adjustable stop 53 which engages the arm 2 and is normally held clear of said arm by the cam 47 on a counterweighted disc 40 having a mutilated worm gear normally free from the screw-thread 46 but adapted to be engaged there.- with when the detent 42 is moved clear of the lug 44 by a track contact member. The disc 40 is then rotated one revolution and a pointer 51 indicates the distance from the signal and the cam 47 allows the lever 49 to fall and engage the arm 3 and cause the application of the brakes if the speed is excessive. The preferred apparatus for releasing the detent 42 comprises a pneumatic bulb 45<a> which is expanded when a plunger 61, Fig. 6, is thrust inwards by the member 64 which is moved axially by rotation of the member 63 when the yoke 65 is struck by the arm 66 on the track. The arm 66 is mounted on a sleeve 72 which is rotated by connections to' the signal. When struck by the yoke 65 the arm 66 is thrown to its lowered position and is held there by the catch 69. The Specification as open to inspection under Sect. 91 (3) (a) describes a recording mechanism which comprises a stylus A attached to the lever 6 which is operated by the cam 9 and slides on a guide-bar C' and marks a paper strip B moved forward by a gear from the train axle. Also, in order to adjust the speed of the train in accordance with the pressure in the brake pipes a plunger 83, Fig. 11 (Cancelled), controlled by a spring 86 and the pressure in the brake pipe 84 is arranged to depress the lever 3 as the pressure is reduced. A ball valve 85 seated on a narrow slot prevents rapid escape of air from the cylinder 81 and consequent unnecessary application of the brakes. This subject-matter does not appear in the Specification as accepted.