US134178A - Improvement in steam and air brakes - Google Patents

Description

G. WESTINGHOUSE, Jr.

Steam and Air Brakes.

Patented Dec. 24, 1872.

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GEORGE WESTINGHOUSE, JR, OF PITTSBURG, PENNSYLVANIA.

. IMPROVEMENT IN STEAM AND AIR BRAKES.

Specification forming part of Letters Patent N0. 134,178, dated December 24, 187:2.

To all whom it may concern:

Be it known that I, GEORGE WESTING- HOUSE, J r., of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Steam-Power-Brake Apparatus; and I do hereby declarethe following to be a full, clear,

and exact description thereof, reference being had to the accompanying drawing making a part of this specification, which represents my invention in plan view or elevation according to the position in which it is placed. My improvement is chiefly designed for taking up automatically the slack motion caused by the wearing of the brake-shoes of railway cars by the bending of a lever or other means, and in such use it is applicable to either hand i or power brakes, the construction and arrangement of the brake-levers and connecting devices being substantially the same in either case. The wearing away of the brake-shoes, it is well known, renders it necessary to readjust the devices somewhat frequently, since the efficiency of a brake depends considerably on the quickness with which it can be set. Where there is more slack motion than is necessary for the brakes to clear the wheels, the

.time of the brakeman, if hand-brakes are used,

is lost in taking up this excess; and if powerbrakes are used both time and power are lost in the same operation.

To enable others skilled in the art to make and use my improvement, I will proceed to describe its construction and mode of operation.

The levers B B may represent the ordinary brake-levers, the lower ends of which are attached, in the usual way, to the brake-bars outside the truck-wheels; or the apparatus power is, communicated to it from the brakewheel by a brake -chain, b, in the usual way. If used with a steam or air or other fluid brake, power is communicated to it from the brakeany one of these holes.

4" of the ratchet-bar R. In it are a series of holes, '6, and a pin or stop, 1', is. inserted in Between the points 1' and r the stem is made smaller, and on this smaller part is a spiral spring, s, though the size of the stem is immaterial provided a suitable spring be arranged thereon with suitable stops at each end. Between the shoulder at "r and the adjacent end of the springs is a bracket, 0, which is fixedly attached to or connected with the brake-cylinder G; or it may be attached to any part of the car, it only being necessary that it should be fixed in position. The end of the spring 8 bears against the bracket 0, and that part of the stem on which thespring is arranged is capable of motion through the bracket 0 to the extent of the compressibility of the spring. The ratchet-bar R, having a ratchet-rack, T at its other end, passes through the ratchet box A, in which a pawl, 6, held down by a spring, 0 engages the teeth of the rack. A similar ratchet-rack, H, is attached preferably to the brake-cylinder O; or it may be attached to the car and extend back through the ratchetboX A. A like pawl, 0 held down by a spring, 0 engages the teeth of this rack.

It will now be obvious that if the upper end of the lever B is moved outwardly by the brake-chain b, or by the piston-stem O, that the lower ends of the levers B B will be moved toward each other, and that by suitable connections with, the brake-shoes the brakes will be set. For this use the ratchet-racks are set, and the pin c" inserted in one of the holes *5, so that the upper end of the lever B may, without engaging the pin, receive only the necessary motion for applying the brakes, but as the brakeshoes wear away the upper end of the lever B will have to travel further be fore the brake-shoes are brought against the wheels, and this additional travel is what is termed the slack motion. The pin z" is so set that when this slack motion becomes too great the upper end of the lever B shall, when the brakes are applied, come against the pin, and thereby draw the ratchet-bar B forward till the pawl e shall slip over and engage the next tooth in the ratchet 1. As the ratchet-bar B is thus drawn forward the part on which the spring 3 is arranged is drawn through the bracket 0, the spring 8 being compressed thereby. Then, when the brakes are released, the spring 8, bearing against the bracket 0, forces the ratchet-bar It, and with it the ratchet-box A and pawl 0 one tooth to the left, so that the pawl c passes over and takes a bite on the next tooth.

It will now be seen that, by the operation described, the position of the upper end of the lever B, relative to the chain 1) or the stem 0, will not be materially changed, that the upper end of the lever B will be thrown back one notch, and that the distance between the fulcrum-point b of the lever B and the point at which power is applied to the lever B is increased by the length of one tooth, and that the lower ends of the levers B B are brought nearer together, and hence brought to such position thatthe brake-shoesin leavingthe wheels will travel only so far as may be necessary in order to clear them. When the shoes become still further worn, so as to give rise to slack motion, or when from any other cause a slack motion is produced, the upper end of the lever B again engages the pin t", with the result already stated. When the brakes are let off, they are carried clear of the wheels by means of the spring a, one end of which bears against a shoulder or stop on the stem m, and the other end against the end of the hollowsocket m, the stem at playing in and out of the socket, as far as may be necessary, and nuts may be employed with this spring as well as with the spring 8 for the purpose of adjustment. The pivoting-points of the stem m and socket m are such that as their leverage, while acted on by the spring n, is decreased, (their pivoting points coming nearer to the line of the tie-bar 1),) the spring a is compressed, and of course its power increased. This leverage is greatest when the apparatus is first put in operation, and the power of the spring is least. As the slack motion is taken up, the bent arms 0 on the levers B B not only move upward, whereby the leverage is decreased, but also approach each other and compress the spring. When the brake-cylinder O is not used at all the ratchet-bar H may be dispensed with; but in such case a stop would be required, as at g,

to prevent too long a backward motion to the lever B, and the ratchet-box A should be fastened to the car. The arrangement before described is, however, preferable.

When the shoes are worn out and new ones put on, of course the ratchet-racks have to be set back. To do this the pawls may be thrown out of gear in any convenient way. As one of many ways that may be devised I make holes 2 through the caps (the upper cap not being shown) at such points that a conical or pointed wire or rod being put therein will pass undef the pawls and throw them out of gear. Then the ratchet-racks may be run back, the pins withdrawn, and the apparatus again be in condition for use. Instead of slotting the lever B and passing the stem 1" through it, the stem may be slotted and the upper end of the lever play therein, and to adapt the apparatus as shown for use as a hand-brake, the pistonstem should be slotted, as is usually done.

It is obvious that by known arrangements of the levers relative to the brakes, the ap paratus shown may be used for applying brakes between the wheels as well as outside, and the ratchet-bar with a fixed pawl and a stop may be combined with a single brakelever, or any lever used in machinery where it is desired to limit the back motion.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. A ratchet-bar, It, connected by the device which carries the pawl c with one of a pair of brake-levers, in combination with a stop which, when the slack motion has become excessive, is engaged by the other lever, whereby the ratchet-bar is shifted, substantially as and for the purposes set forth.

2. The subject-matter of the preceding claim, in combination with a ratchct'bar, H, arranged and operated substantially as set forth.

3. A ratchet-bar, R, having a stem, 0, and rack T in combination with the pawl e, a lever, B, and stops t" and g, substantially as set forth.

4. The bent arms 0 on the levers B B, in combination with stem m, socket m, and spring n, suitably arranged, whereby, as the leverage is decreased the power of the spring is increased, substantially as set forth.

In testimony whereof I, the said GEORGE WESTINGHOUSE, J r., have hereunto set my hand.

GEORGE WESTINGHOUSE, JR.-

Witnesses:

A. S. NICHOLSON, G. H. OHRIsrY.

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