Lanterna Rally

Author: Westinghouse Air Brake Company

Publisher: Theclassics.Us

Published: 2013-09

Total Pages: 24

ISBN-13: 9781230339405

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1901 edition. Excerpt: ...brakes their highest efficiency, without the flat wheels which are likely to accompany a wide range of piston travel. This device establishes the running piston travel; that is, the piston travel occurring when the brakes are applied while the car is in motion; and, since this is the time during which the brakes perform their work, the running travel is the important one. Hand adjustment necessarily relies upon the standing travel, and it is only coarsely graded, at best, by the spacing of the holes in the dead-lever guide. The Automatic Slack Adjuster is illustrated on Plates 21 and 22, and its operation is very simple. The brakecylinder piston acts as a valve to control the admission and release of brake-cylinder pressure to and from pipe b (Plate 21) through port a in the cylinder, this port being so located that the piston uncovers it when the predetermined piston travel is exceeded. Whenever the piston so uncovers port a, brake-cylinder air flows through pipe b into slack-adjuster cylinder 2, where the small piston 19 (Plate 22) is forced outward, compressing spring 21. Attached to piston stem 23 is a pawl, extending into casing 24, which engages ratchet wheel 27, mounted within casing 24 upon screw 4 (Plate 21). When the brake is released and the brakecylinder piston returns to its normal position, the air pressure in cylinder 2 escapes to the atmosphere through pipe b, port a and the non-pressure head of the brake cylinder, thus permitting spring 21 to force the small piston to its normal position. In so doing, the pawl turns the ratchet wheel upon screw 4, and thereby draws lever 5 slightly in the direction of the slack-adjuster cylinder, thus shortening the brake-cylinder piston travel and forcing the brake shoes nearer the...