US199161A - Improvement in car-brake shoes - Google Patents

Description

W. MGCONWAY. Gar-Brake Shoe.

No. 199,161.l Patented 1an. 15,1878.

Wwssus n. Firms,

UNITED STA'InsPATn-nnimnnmn.

WILLIAM MCCON WAY, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT `IN CARI-BRAKE SHOES.

l Specification forming part of Letters Patent N0. 199,161, datedJanuary 15, 1878 applicationled November 21, 1877.

To all whom it may concern Be it known that I, WILLIAM McCoNwAY, of Pittsburg, county of Allegheny, State of Pennsylvania, have invented or discovered a new andV useful Improvement in Car-Brake Shoes; and I do hereby declare the following to be a full, clear, concise, and exact description thereof, reference being had to the accompanying drawings, makingl a part of this specification, in which-like letters indicating like parts- Figure l is a perspective view of my improved car-brake shoe, one corner beingbroken away in part. Fig. 2 is a transverse sectional view through the plane :o a', Fig. l. Fig. 3 is a like sectional view through the line y y of Fig. 1; and Fig. 4 is an outline perspective view of blocks of metal used in the shoe, as hereinafter described, and also showing a bar or blank from which such blocks may be cut.

My improved brake-shoe belongs to that class the face or rubbing-surface of which is composed of two or more metals, or qualities or kinds of the same metal.

In making brake shoes of this class, the method heretofore followed has been to prepare a sand mold in the vusual way, and into the mold lay pieces of wrought-iron, steel, or other like metal. Molten cast -iron is then poured in, which covers and more or less fuses with the wrought-metal pieces, thus permanlently embedding them in the body of the s oe.

This mode of manufacture is objectionable, because the molten metal, coming in contact with the solid iron, is hardened in cooling, the solid liron acting as a chill This chilling or hardening of the shoe renders it liable to cut and wear the tread of the wheel when applied in ordinary use; and also by hardening castiron its adhesive or frictional qualities are veryr much impaired, thus lessening its efficiency when used in brake-shoes.

Another objection to brake-shoes made' in this way is, that such shoes, when worn out, are practically useless as scrap. This arises from the necessity of separating the different grades of metal, which is diiiicult and expensive Where the different grades are united or fused together in casting, as before described.

By my improvement I secure the advantages derived from using dierent grades of metal in the shoe. I also obtain a soft cast meta-l, inclosing the wrought metal in such manner that the different grades may be readily separated, when desired, for scrap.

My improved shoe consists of a cast-iron frame, A, having cavities cast therein, in which are placed blocks B of wrought-iron, steel, or other like metal, and these blocks are secured in place partly `by the form of the cavities, and partly by a back-piece, C, which is, by preference, made of malleable iron, and is riveted to the back of the frame A, as presently described.

The several parts of my improved shoe are made as follows: An ordinary sand mold is prepared for casting the frame A, within which mold are arranged cores for forming the desired number of cavities in the frame. I prefer to make these cavities extend through the frame from back to face, and pyramidal in form, or of such form that at the base or back of the frame they shall be greater in area than at the face or front. The blocks B can then be put in place and removed only from the back. I also arrange studs or pins a, four or more in number, within the mold, in such manner that the metal of the frame Will be cast around one end of the pins, thus securing them firmly, while the free end will be left to project from the back of Jthe frame far enough vto form posts vor rivets for securing the backpiece C.

The blocks B may be made by cutting pieces of proper size from a bar, which are swaged or pressed to the desired form to fit the cavities in the frame A. The bar or blank from which these blocks are cut may, however, be rolled to a form in cross-section adapted to a corresponding section, or to two sidesl of the cavities in the frame, and the blocks cut from such bar may then be swaged or pressed to shape, as before described. Such a bar is shown in the drawings, Fig. 4.

The back-piece G is made, by preference, of malleable iron or other like tough material, and has two or more lugs or studs, o, or other like devices, projecting from the back, by which the shoe is secured to the brake-shoe block or holder. This back-piece C is made to it the back of the frame A, as shown in Fig. 1, and the metal used in its construction is manipulated in the manner common in the art.

In securing this back C to the frame A, holes are made through it corresponding to the rivet a, and, after putting the blocks B in place in the cavities in the frame, the backpiece is placed upon the frame, with the rivets protruding through the holes. These rivets are then headed, as shown at a', when all parts of the shoe will be bound together and securely held in place.

A brake-shoe constructed as described, so as to bring different grades of metal in the face, will wear much longer than one which is made wholly of cast-iron; and on account of the softness of the cast metal, which I thus secure, the shoe will operate much more efliciently than one in which the cast metal is chilled or hardened, as has heretofore been done; also, when the shoe becomes Worn the back C may be removed by cutting the rivets a, and the worn parts easily separated for scrap, while'the back itself may be used againin constructing a shoe of the same type.

A- back-piece thus made may, indeed, be used an indefinite number of times, and serve the required purpose equally as well as a new one. Thus my improvement has in view not only increased utility, but also economy.

I claim herein as my invention- 1. A car-brake shoe consisting of a castmetal frame, A, having one or more recesses extending through the same from back to face, in combination with insertible blocks B, adapted to the form of such recesses, and a removable back, C, substantially as described.

2. A rubber for car-brake shoes consisting of a cast-metal frame, A, in combination with one or more detached blocks, B, insertible from the rear, substantially as and for the purpose described.

In testimony whereof I hereunto set my hand.

. WILLIAM MCGONWAY.

Vitnesses J. J. MCCORMICK, GEORGE H. CHRISTY.

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