US596132A

US596132A - Andrew j

Info

Publication number: US596132A
Authority: US
Publication date: 1897-12-28
Anticipated expiration: 1914-12-28

Description

(No Model.)

A. J. ALLEN 85 J. F. MORRISON.-

BRAKE SHOE.

No. 596,132. Patent-ed Dec. 28, 1897.

UNITED STATES PATENT since.

-ANDREW J. ALLEN AND JAMES F. MORRISON, OF CHICAGO, ILLINOIS.

BRAKE-SHOE.

SPECIFICATION forming part of Letters Patent I\To. 596,132, dated December 28, 1897.

Application filed May 29,1897. Serial No. 688,792. (No model.)

To mZZ whom; it may concern:

Be it known that we, ANDREW J. ALLEN and JAMES F. MORRISON, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Brake-Shoes, (Case No; 1,) of which the following is a full, clear, concise, andexact description, reference being had to the accompanying drawings,forming a part of this specification.

Two typesof brake-shoes are well known in the artone, the composite shoe, in the form of a shell, in which is placed a compound forming a surface which frictionally engages the wheel when the brake is applied. The other type has a frictional surface of an integral piece'formed in alternate sections of soft and chilled metal.

Our invention relates particularly to the first class of brake-shoes, and in its preferred embodiment has certain characteristics common to the two types mentioned.

Heretofore a composition consisting of sawdust, comminuted iron, asbestos, plumbago, resin, and linseed-oil, thoroughly intermixed, has been, among others, employed for the friction body of the shoe, such composition being pressed within the shell either in a hot or cold condition. The linseed-oil acted tobind the ingredients together. The component parts of the mass were thoroughly intermixed either in a hot or cold condition. If mixed in a hot condition, the carbonizable elements of the masswere frequently burn ed and partially reduced to carbon, whereby the efficiency of the compound was greatly impaired, the frictional character thereof being lessened,

' while the binder failed to properly perform gagement between the wheel and shoe as to cause the carbonization of the sawdust and linseed-oil, the subsequent disintegration of the body rapidly ensuing.

Compounds heretofore employed for brakeshoes were rigid and unyielding to such a degree that a severe application of the brake would look the wheel and shoe together and cause the wheel to skid. v

Our invention consists in a composition for forming or partially forming the surface of the brake-shoe, in the manner of manufacturing the said composition, and in the particular combination of such composition with the metal parts of the shoe.

The composition which we, have invented is composed, essentially, of comminuted iron, worked asphaltum, and Wahsatch rock, mixed together, preferably in the following manner and in substantially the proportions named. The asphaltum is melted under a temperature of, say, 400 Fahrenheit, and the comminuted iron, as iron chips or iron turnings, is then mingled therewith, after which the Wahsatch rock in the form of powder is added, the entire mass being thoroughly commingled.

We have found that the best results are obtained by using eighteen parts of iron to one part of asphaltum and one part of Wallsatch rock, by weight.

The asphaltum acts as a binder and also imparts elasticity to the composition, while the Wahsatch rock counteracts this elasticity and also acts to a certain extent as a binder.

The degree of elasticity and the coefficient of friction are governed by the amount of the added Wahsatch rock.

'VVhere materials such as those we have specified are employed, the mass is thoroughly coherent throughout, whereby a separation or disintegration is impossible, and even though the heat generated by friction in the application of the shoe to the wheel may be very great the only effect will be to make the friction body slightly more ductile, and this condition will exist only during the presence of the excessive heat.

Our composition is such that granular particles are not formed between the brake and the shoe, and the frictional engagement is slightly yielding,so as to prevent the shoe from becoming rigidly clamped upon the wheel to cause the same to skid.

Our composition when used in brakes applied to wheels having small holes or imperfections as it is worn off fills such holes or depressions as may exist in the tread of the wheels, thus causing the wheels to conform to the outline of the working or frictional surface of the brake.

'We will describe the manner of compressing the composition into the iron shells of the shoe and the combination of the composition with the shell and the enlarged and taper chilled ends thereof in connection with the accompanying drawings, in which- Figure 1 is aside view of the shell with the frictional body. Fig. 2 is a front View thereof, and Fig. 3 is a cross-sectional View on line 3 3 of Fig. 1.

Like letters indicate like parts in the different views.

The shell a is provided with suitable eyes Z) 1), whereby it may be united with the head of the shoe. The interior walls of the shell slope from the back to the front thereof, asis clearly indicated. The composition dis forced within the shell under heavy pressure and preferably while in a hot condition. The mass is thus solidified to the required degree and firmly embedded within the shell. By tapering the walls the dislodgment of the mass is prevented.

lVe preferably make the ends 0 c of the shell thick and chill the same during the process of casting. The ends are preferably taper chilled, diminishing from the place of greatest hardness at the front of the shoe toward the softness of the unehilled portion of the shell at the back of the shoe, as is indicated by the shading of the shell in Figs. 1 and 2.

The friction body in the newly-manufactured shoe preferably extends beyond the shell, as shown. As the body is worn down the hardest portions of the chilled ends are engaged by the wheel. As the brake-shoe is worn away the chilled ends thereof gradually become softer, while the engaged area of the frictional body gradually increases, the intention being to have the resultant frictional effect of the chilled ends of the shoe and the frictional body maintained constant by the gradually-increasing frictional area of the body and the gradually-reduced hardness of the ends of the shoe as the shoe is worn away.

Shoes made in accordance with our invention have an increase of life fully thirty-five per cent. above that of any shoe now on the market.

Having thus described our invention, what We claim as new, and desire to secure by Letters Patent, is-

1. A composition for brake-shoes, consisting of comminuted iron asphaltuin and Wahsatch rock intermixed in substantially the proportions specified.

2. The combination with the shell of a brake-shoe having enlarged taper chilled ends, the inner surfaces of the walls of the shell sloping from the back to the front thereof, of a composition contained within the shell comprising comminuted iron, asphaltum and Wahsatch rock intermixed in substantially the proportions specified.

3. The combination with the shell of a brake-shoe, having enlarged taper chilled ends, the inner surfaces of the walls of the shell sloping from the back to the front thereof, of a frictional body conforming to the interior of the shell, the frictional area of the body being enlarged as the shoe is worn away to compensate for the decreasing hardness of the chilled ends of the shoe.

'1. A composition for brake-shoes, consisting of comminuted iron, asphaltuin and an ingredient to counteract the elasticity of the asphaltum, substantially as described.

In witness whereof We hereunto subscribe our names this 25th day of May, A. D. 1897.

ANDREWV J. ALLEN. JAMES F. MORRISON. \Vitnesses:

GEORGE L. CRAGG, D. W. O. TANNER.