US35967A - Improvement in car-brakes - Google Patents

Description

J. M. BROWN.

Car Brake.

Patented July 22. 1862.

N.'PETER5. FHOTO-UTMDGRAPMER. WASHINGTON. D C.

UNITED STATES PATENT OFFICE.

JOSEPH M. BROWN, OF CINCINNATI, OHIO, ASS IGNOR TO HIMSELF AND DANIEL MOLAEEN.

IMPROVEMENT lNCAR-BRAKES.

Specification forming part of Letters Patent No. 35,967, dated July 272, 1862.

To aZZ whom it may concern.-

Be it known that I, JOSEPH M. BROWN, of

Cincinnati, Hamilton county, Ohio, have invented a new and useful Improvement in Oar- .Brakes; and I do hereby declare the following to be a full, clear, and exact description of the nature, construction, and operation thereof, reference being had to the annexed drawings, making part of this specification.

My invention relates to a provision whereby an excessive strain upon either the brake-rope or the Windlass acts automatically to draw out said rope and to relax or remit a portion of the tension proportionate to said excess.

Figure 1 is a perspective view of the rear end of a locomotive provided with my improvement. Fig. 2 is an axial section through the Windlass.

A represents the platform, and B Bthe rear drive-wheels, of a locomotive.

G O are brackets depending rigidly from the frame or platform.

D is a rock-arm hinged below to bracket 0 and having its free or upper end connected by a rod, E, to a lever, F, under control of the engineer.

G is a swinging shaft journaled at one. end by a stationary but slightly rotating bearing, H, in bracket 0, and journaled near the other end at I in the rock-arm D. The free extremity of the shaft G carries a grooved frictionwheel, J, which, when the rock-arm is thrown forward, engages with the flange of the drive wheel, so as to derive motion from the latter. The shaft G also carries near its free end a ratchet-wheel, J, which receives a pawl, K, pivot-ed to bracket 0.

L M are a rod and lever which enable the engineer, by disengaging the pawl, to release the brakes.

The shaft G carries two hollow cone-collars, of which one, N, is fast to the shaft, and the other one, 0, though compelled to rotate with the shaft, is capable of a slight longitudinal adjustment along the shaft by means of a nut,

P, and a gum or other spring, Q.

Between the fast and loose collars N and O the shaft G carries a spool-shaped Windlass or drum, It, hung so as to both slide and rotate freely upon the shaft G, except when tightly grippedbetween the collars N and O by means of the nut P and spring Q, as hereinafter excars upon the cable.

plained. When thus gripped, the windlass is as if it were immovably attached to the shaft G until an excessive tension occurs, when the Windlass slips around between the cones, and by letting out a part of the cable relieves the parts from undue strain. The degree of strain which shall produce this relaxation of the tension is subject of accurate adjustment by the engineer, who, before'starting, screws the nut P slightly in or out, according to the maximum tension desired for the brake.

S represents a wire cable, rope, or chain attached to the loose Windlass R and communieating with a suit of brakes throughout the train in any approved way.

Operation: The engineer first carefully adjusts the maximum tension by means of the nut P, and having tested the apparatus by actual operation corrects any excess or deficiency by the same means. The tension having been thus duly regulated, no after-adjustment will ordinarily be needed other than such slight occasional setting up as may be rendered necessary by the wear of the parts. Now, suppose it be desired to stop the train, the speed of the engine having been slackened in the usual manner, the lever F is drawn backward (see Fig. 1) so as to impinge the wheels J and B and cause the Windlass to rapidly wind up the cable S. The action of stopping causes the several cars to crowd up closely to gether, which results in the slackening of the cable; and hence the first office of the windlass is to take up this slack, which being accomplished, the tightening of the cable acts to shut down the brakes. If, now, the friction-wheel J be cdntinued in contact with the driver a moment longer than necessary, the excessive strainwould cause the cable or some other part to snap, were it not for the slip of the Windlass itself upon its shaft. This slip makes it impossible by winding up the wind-.

lass to increase the tension beyond a specific point. The primary tension of'the Windlass itself is thus effectually graduated; but there is another and. more serious difficulty, hither-- to, so far as known, fatal to this class of-devices-namely, the retroactive strain of the The crowding together of the train already alluded to, which always accompanies a stoppage, is as invariably succeeded by a lengthening of the train as the 1 I r y reaction of the hunters obliges the several cars to resume their normal distances. If, now, the cable be not instantly slackened, something must give way. A mere limitation of the initial tension can afford no relief to such stretching of the cable by the action of the lengthening train, and hence the rapid destruction of those devices which merely graduate the Windlass tension.

WVith my improvement any sudden or violent strain upon the cable acts merely to slip the Windlass and to draw the cable out, while any slack resulting from the shortening of the train or other cause is immediately taken up by the Windlass.

It will be seen that under any and all contingencies a uniform and effective tension is maintained without endangering the parts.

The present illustration of my invention has been selected as that which practical test on several roads has proved to be effective; but I do not desire to confine myself to the precise construction here described so long as the objectis effected by means substantially eqniva- ]entas, for example, the shaft G may be hung in stationary bearin gs and be driven by a small rotary engine secured beneath the platform.

The friction-surfaces of the collars and windlass may be in planes at right angles to the shaft, or, if conical, their axial section may present curved instead of straight lines. The graduating-nut Pmay be placed under the instant control of the engineer by means of a ratchet wrench or other device extending above the platform.

I claim herein as new and of my invention- The shaft G, having a fast collar, N, and an adj ustable collar, 0, loose friction Windlass R,

nut P, and spring Q, or their equivalents, the whole being so combined as to produce an automatic relaxation of excessive brake-tension, substantially as set forth.

In testimony of which invention I hereunto set lnyhand.

J. M. BROWYN. Witnesses:

GEO. H. KNIGHT, D. DIOLAREN.

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