Patent GB-359393-A (GB)
Title: Improvements in brake systems for marshalling railway wagons
IPC: B61K7/04
Filed: 1930-05-12
Abstract: 359,393. Brakes. RABOURDIN, J., 195, Avenue du Maine, Paris. May 12, 1930, No. 14572. Convention date, May 11, 1929. [Class 103 (i).] The invention comprises an improvement in the braking system described in French Specification 663,039, wherein a shunting yard track comprises braking sections and standing wagon sections, the latter having each a track relay energized on occupation, and in which a wagon as it runs over the braking sections is braked to an extent depending on the nearest occupied standing wagon section. In each braking section there is a brake shoe normally positioned at the front part of the braking section which is moved along the track in one direction by a motor and side tracked towards the exit end of the section. The motor also effects the return movement of the shoe. Each braking section has a timing device comprising a stepping contact arm which is started by the entry of a wagon into the section and moves over a bank of contact studs and on reaching a live contact stud starts the motor to withdraw the brake shoe into the side track. The position of the live contact stud determines the time which elapses between the entry of the wagon into the section and the withdrawal of the brake shoe and therefore, depending on the wagon speed, whether the front wheel of the wagon engages or does not engage the brake shoe. The first contact stud reached by the stepping arm is normally connected with the farthest standing wagon section (Sn) and the last contact stud reached by the stepping arm is connected with the first standing wagon section (S1). When standing wagon sections are occupied up to section Sr say, the track relay of this section closes a first contact to apply voltage to the contact stud r of the timing device and opens a second contact which isolates the first contact connections of all the track relays in advance (in the direction of travel) of this section so that voltage is applied only to contact stud r notwithstanding that other standing wagon sections in advance are occupied. To adjust the braking for different weather conditions a controller consisting of hand-controlled switch devices is provided to alter the association of the track relay contacts with the contact bank of the timing device. In the above system a wagon having a speed such that it will pass through a particular standing wagon section will nevertheless impose on a following wagon a braking corresponding with that with a wagon at rest in such section. The present invention avoids this defect by the insertion of a timing device of the same general nature as described above between the standing wagon section track relay contact and the manually adjusted controller. A wagon passing through standing wagon section S1 causes contacts of track relay RV1 to close and thereby start the timing device which comprises a continuously rotating cam 88 which opens and closes contact 4, 5 to operate the stepping magnet RMa of the device. If the wagon speed is such that it would come to rest in, say, section S3 then it passes through section S1 in such time that the stepping contact arm Fr, 1a has only moved to a bank contact such that positive voltage is applied to the point Bc3 of the controller and the braking on a following wagon is therefore that corresponding to that with a wagon standing in section S3. Should the wagon be travelling very slowly or at rest in section SI, then when the stepping contact arm reaches position (P1, P2, P3) the device is stopped since the stepping magnet RMa is de-energized by the opening of contact 6, 7 when the winding Ra is energized over contact P2 of bank CIIa and contact 8, 9 of track relay RV1. In this stopped position of the timing device positive voltage is applied to the point Bc1 of the controller so that the braking applied to a following wagon corresponds to that for a wagon standing in section S1. When the wagon moves out of section S1 the actuating circuit of the timing device is closed over bank CIIIa and contact 1, 3 of the now deenergized track relay RV1 to move the stepping contact arm forward until it stops in its initial position shown.