US1518724A - Hand brake mechanism - Google Patents

Description

Dec. 1924- 1,518,724

H. l. WRIGLEY, I

HAND BRAKE MECHANI SM Filed Aug. 2, 1922 OOOOOOOOOOOOODOOOU Patented Dec. 9, 1924.

UNITED STATES PATENT OFFICE.

HENRY I. WRIGLEY, OF CHICAGO, ILLINOIS, ASSIGNO'R T0 UNIVERSAL DRAFT GEAR ATTACHMENT 00., A CORPORATION OF ILLINOIS.

HAND BRAKE MECHANISM.

j Application filed August 2, 1922. Serial No. 579,249.

T 0 all whom it may concern.

Be it known that I, HENRY I. WRIGLEY, a citizen of the United States, and resident of Chicago, county of Cook, and State of'Illinois, have invented certain new and useful Improvements in Hand Brake Mechanism, of which the following is a specification, and which are illustrated in the accompanying drawings, forming a part thereof.

The invention relates to hand brake mechanism adapted for use on railway cars.

The object of the invention is to provide improved means for taking up the slack of the several brake connections, and thereby bringing the brake shoes into engagement with the wheels of the car as soon as possible after the initial application of power; secondly, after the brake shoes are in contact with the wheels, to press them against the treads with great force; and thirdly, to provide means adapted to set the brakes with the same force, after parts of the connections have become worn, as is available when the brake mechanism is first installed.

The invention further relates to the specific mechanism employed for accomplishing the various objects above enumerated- An illustrative embodiment of the invention is shown in the accompanying drawings, in which Fig. 1 is a detail view showing in elevation a portion of the improved brake operating mechanism, the position of the parts being that corresponding to the released position of the brakes;

Fig. 2 is a detail plan View of the mechanism illustrated in Fig. 1, showing the same position of the parts and the brake staff being shown in section;

Fig. 3 is similar to Fig. 2 but shows the operating mechanism in the position occupied after the slack in the various brake connections has been taken up, preparatory to the application of the full braking power; and

Fig. 4 is a detail side elevation of a railway car showing the brake operating mechanism applied thereto.

A detail of the nnderframe of a railway car is represented in the drawings at 10. In the particular arrangement illustrated the improved hand brake operating mechanism is intended for use only when the car is detached from the train, the brakes (not shown) being normally operated by the usual air cylinder 11, push rod 12, and cylinder lever 13. The hand brake staff 14 is also of the usual form, being journaled at its lower end in the customary brake staff support 18.

In carrying out the invention the hand brake rod 21, shown as being attached to the push rod 12 by means of a pin 22, is formed with a fork 20 at its forward end, and a drum 25 is rotatably mounted between the arms of the fork 20, as upon a spindle 24. The drum 25 is preferably formed with two spiral chainways 26, 27, one for each of two chains or cables 28 and 29, the chain 28 extending to the brake staff 14 for winding engagement therewith in the usual man ner, and the chain 29 extending to a fixed anchorage, as the brake staff support 18. to which it is attached by a clevis 32. The chainway 26 may be of uniform diameterthroughout, and the staff chain 28 is attached to the drum 25 near one end portion of this chainway, as at 31 (Fig. 2). In the normal position, with brakes released, the chain 28 preferably makes one complete turn about the drum 25 in the chainway 26.

The chainway 27 comprises a portion 36 of uniform diameter, preferably much smaller than the diameter of the chainway 26. However, for the purpose of immediately taking up slack in the brake rigging upon the initial movement of the drum 25, the chainway 27 preferably also comprises an eccentric portion extending radially outward in the form of an eccentric arm 30, which arm, as shown, is longer than the radius of the chainway 26. One end of the. chain 28 is accordingly attached to the drum 25 at one side of the arm 30, as at 33, for winding engagement of this chain first with the end of the arm 30 and then into the smaller part 36 of the chainway 27.

In the position shown in Figs. 1 and 2, with brakes released, the outer end of the eccentric-arm 30 is toward the point of anchorage 32 of the stay chain 29. When the drum 25 is rotated by turning the brake staff 14 and drawing on the staff chain 28, the eccentric arm 30 is moved away from the point 32, winding the chain 29 in this enlarged part of the groove 27 and quickly taking up any slack in the brake connections. As soon, however, as the stay chain has been wound over the eccentric arm 30, it engages the smaller portion 36 of the chainway 27, thus decreasing the effective wlnding diameter of the drum and increasing the power which is exerted by the staff chain. Furthermore, the relatively large diameter of the chainway 26, from which the staff chain 28 is drawn, permits a great deal of force to be exerted for applying :the brakeshoes to the wheels after the slack in the brake rigging has been taken up.

That is to say, movement of the hand brake rod 21 is effected in accordance with the shortening of the stay chain 29, 'due to the winding of this chain upon the drum After the eccentric arm 30 has been passeo, the winding of the stay chain 29 upon the drum is accomplished with great power due to the fact that this chain is being wound upon a part of the drum which is of small diameter, while thedrumis being turned by drawing the chain 28 from a part of the drum which is of large diameter.

It is desirable to take up the slack of the several brake connectionsand engage the brake shoes with the wheels with the increased power as speedily as possible. To this end the lengths of the chains 28 and 29 are so selected that when the brake mechanism is new all the slack will bB'tflliEll up and the brakes pressed firmly against the wheels after only a partial rotation of the drum 2. However, as the brake shoes and other parts of the mechanism are subject to wear, a partial rotation of the drum 25 is sometimes found insufficientto perform the braking operation. By having a plurality of turns of the spiral groove or chainway 27 upon the reduced'portion of the drum allowance for a considerable amount 01 wearis provided for, permitting the continuous application of the increased power for any desireddistance. A steady'and uniform pressure is maintained upon the wheels with double or any otherincreased power relative to the initial power applied for taking up slack, the ratio depending on the length of the eccentric arm 30 as compared with the diameter of the remainder of the chainway 27. The actual power applied is, of course, dependent on the relative diameters of the chainway 26 and concentric portion of the chainway 27.

While a preferred embodiment of the invention is shown and described with at particularity, many of the details may be varied without departing from the spirit of the invention. F or example, while two separate chains are shown, each guided in a separate groove, it is evident that a one piece chain secured to the drum adjacent its ends, and having one end anchored and the other in winding engagement with the brake staff, may be employed in place of the two part chain herein disclosed. The Word While the hand brake mechanism is shown as connected with the push rod of the air brake mechanism, this is not important, it being necessary only that there be a connection with the brake lever. The connection between the drum and the brake lever is shown as a rod according to common practice, but for the purpose ofthis invention it is important only that this connection be capable of transmitting draft.

I claim as my invention 1. In-abra'ke mechanism for railway cars, in combination, a rotatable brake staff, a brake lever, and connection between'thestali and lever including alink attached at one end to the lever, a drum journaled in the other end of the link and having eccentric and concentric portions, a spiral groove on the periphery of the drum extending continuously over the-eccentric and'concentric portions, a cable adapted to be guided in said groove having one end secured to the drum and the other end fixedly anchored, and a secondcablehaving its opposite ends in winding engagement with the drum and the brake staff, respectively. V

2. In a brake mechanism for raiiway cars, in combination, a rotatable brake staff, a brake lever, and connectionbetween the staff and lever including a link attached at one end to the lever, a drum journaled in the other end of the link, said drum having concentric portions of different diameters and an eccentric portion formingacontinuation of the concentric portion-sot smaller diameter, and two cables attached to the drum one for winding engagement with the smaller concentric and the eccentric portions of the drum and the other for winding engagement with the larger concentric portion of .the drum, the other end of the first separately mentioned cable being fixedly anchored and the other cable extending to the brake staff for winding engagement therewith.

S. In a brake mechanism for railway cars, the combination of a brake staff, a brake lever and an expansible and contrac-table connection between them including a Totatable element having a largedrum surface and a small drum surfaceprovided with an arm extending radially from one side there-j of, means secured to the axle of therota'table element and to the brake lever, a-cable I-in winding engagement with the large drum surface and the brake staff and asecond cable anchored at one end and in winding engagement with the small, drum surface and the arm thereon.

HENRY I. WVRIGLEY.

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