US736350A - Brake-shoe. - Google Patents

Description

PATENTBD AUG, 18, 1903. T. M. BELL. BRAKE SHOE. l

NTTED STATES Patented August 18, 1903,

THOMAS M. BELL, OF PHILADELPHIA, PENNSYLVANIA.

BRAKE-SHOE.

SPECIFICATION forming part of Letters Patent N o. 736,350, dated August 18, 1903.

Application 'lled November 19, 1902. Serial No. 132,019. (No model.)

To @ZZ wiz/0m it may concern:

Be it known that I, THOMAS M. BELL, a citi- Zen of the United States, and a resident of Philadelphia, Pennsylvania, have invented certain Improvements in Brake Shoes, of which the following is a specification.

One object of my invention is to so construct a brake-shoe with reinforced back as to prevent injury to the shoe by reason of the` unequal strain thereon due to the heating of the shoe when in use.

Another object of the invention is to enable an inspector to readily determine the fact that a shoe has a reinforced back and to indicate the safe limit of wear of a shoe.

These objects I attain in the manner hereinafter set forth, reference being had to the accompanying drawings, in which- Figure l is a vertical section of a brakeshoe with reinforced back constructed in accordance with my invention. Fig. 2 is a transverse section of the saine on the line a a, Fig. l and Figs. 3 to 7, inclusive, are views illustrating modifications of the invention.

Owing to the use of high-pressure air-brakes upon modern railway cars, it has become necessary to reinforce the ordinary cast-iron brake-shoes, so as to enable them to resist the higher strains to which they are subjected, and many plans have been devised for effecting such reinforcement, most of them involving the embedding in the cast-iron shoe of some form of strengthening web, wires, or equivalent device of steel -or wrought metal having a high degree of tensile strength. Rolled or pressed steel or like wrought metal, however, has a tendency to expand and contract differently from the cast-ironunder the influence of heat. Hence when ordinary reinforced shoes become heated by reason of their frictional contact with the rotating wheel fractures are formed in the cast metal which, even if not sufficient to interfere with the performance of its proper f unctions by the shoe, cast a doubt upon its integrity and lead toits condemnation. These cracks are also sometimes formed in the shoe during the cooling of the casting and before the same is put into use. In carrying out my invention, therefore, I provide the cast-iron shoe with a reinforcing-web composed of a steel casting, for I find that `ROSS, Ol eVell SOOIIOI.

the latter is affected by variations of temperature in substantially the same manner as the cast-iron, and hence will not lead to any disruption or fracture of the latter either in the cooling of the original casting or in the heating and cooling to which the shoe is subjected when in use.

In the drawings, l represents the cast-iron portion of the shoe, and 2 the reinforcing web or plate, composed of asteel casting, the same being so firmly keyed to the cast-iron portion of the shoe as to be effectually retained in place therein or thereon.

An ordinary cast-iron shoe is replaced when worn` away to about one-half its original thick- W'hen the shoe has a reinforced back, however, it can be worn much thinner-almost down to the reinforcement, in fact; but as such shoes have no means whereby to indicate that they have reforced backs they are discarded by the inspectors when worn only as much as a common cast-iron shoe, and hence a considerable period of their usefulness is wasted. It is therefore advisable to construct shoes of this character so that the fact of their having reinforced backs can be readily determined by a casual inspection and so that the limit of safe wear of the same may be indicated, thereby preventing the shoe from Abeing discarded when only partially worn. This object I attain by imparting a special external form to the shoe which will be apparent at a casual glance, so that the inspector can tell instantly whether the shoe is one having a reinforced back. The preferable method of accomplishing this result is to providethe shoe with a laterally-projecting rib or ribs at one or both sides or at top or bottom, or at all of these points. This rib can conveniently be formed by projecting the edges of the reinforcingweb 2 beyond the limits of the cast-iron body l of the shoe, as shown at 3 in Fig. 2, or ribs may be formed upon the cast-iron body, as shown at 2i in Fig. 3, if the reinforcing-web is not as wide as the cast-iron portion of the shoe, or instead of forming a projecting rib upon each side of the shoe a groove may be formed in each side of the same-as shown, for instance, at 5, in Fig. 4-and'- ribs or grooves may extend from topV to bottom of the IOO shoe or only throughout a portion of the eX- tent of the same, as shown at 6 in Fig. 5, ora group of short ribs or grooves in line with each other may take the place of a single rib or groove, and the indicating ribs or grooves may, if desired, be at one side only of the shoe instead of on both sides or at top or bottom or top and bottom-as, for instance, at 7.in Fig.

'-or at the back of the shoe, as at 8 in Fig. 7.

The objection to the latter plan is that although it indicates to casual inspection the presence of the reinforcing-back it does not indicate the safe limit of Wear of the shoe, and the external indicating device should by preference bear such relation in all cases to the reinforcing member as to indicate such wear limit, or, in other Words, should indicate when the reinforcing member is about to be exposed by the wearin g away ofthe cast-iron face of the shoe.

I have shown my invention as applied to a flat brake-shoe intended to act upon the tread of the wheel; but it will be evident that it is applicable as well to shoes which are groovcd for the reception of the wheel-flange.

Having thus described my invention, I claim and desire to secure by Letters Patentl. A castiron brake-slice havin g combined therewith a reinforcing-Web consisting of a steel casting, substantially as speciiied.

2. A brake-shoe having a reinforcing member combined therewith and having an eX- ternal formation indicating the presence of such reinforcing member, substantially as specified.

A brake-shoe having a reinforcing member combined therewith, said shoe being also provided with a side formation indicating the presence of said reinforcing member, substantially as specified.

4L. A brake-shoe having a reinforcing member with projection constituting an external feature of the shoe, substantially as specified.

5. A brake-shoe having an external portion which indicates the safety limit to which the shoe may be worn, substantially as speciiied.

6. A brake-shoe having a reinforcing member therein, and an external portion indicating the safety limit to which the shoe may be worn, substantially as specified.

In testimony whereof I have signed my name to this specication in the presence of two subscribing witnesses.

THOMAS M. BELL.

Witnesses:

J. P. KELLY, J E. GLEAsoN.

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