US2035720A - Brake shoe - Google Patents

Description

R. B. POGUE BRAKE SHOE March 31, 1936.

Filed May 16, 1934 Patented Mar. 31, 1936 UNITE STATES PAT BRAKE SHOE Application May 16, 1934, Serial No. 725,893

7 Claims.

This invention relates to brake shoes which have a reenforce embedded in the body at the back thereof.

Heretofore this reenforce has generally been a steel plate and the lug formed on the shoe to enable it to be attached to a brake head has consisted of a steel strap bent to form a keyway with its ends engaged beneath the steel back. Projections from the shoe body have been provided to enclose the sides of the lug strap to protect and strengthen the strap against deformation in handling and against cutting contact with the brake head in service.

The plate back has been made as wide as possible for maximum strength and a margin of about three-.eighths of an inch has been provided between each side edge of the plate back and the adjacent side of the shoe, which margin has been sufiicient to permit the body metal to make anchoring engagement with the side edges of the plate back during the casting operation but has not been suflicient to provide substantial anchorage for the projections at the sides of the attaching lug. Hence it has been the practice to recess or upset the side edges of the plate back to produce a satisfactory anchorage for the projections with the body of the shoe, and this recessing or upsetting has necessarily resulted in a corresponding reduction in the width and strength of the back. Sometimes the plate back has been cut out between the recessed or upset marginal edges to permit the body metal to form a projection in the attaching lug, and such cutout further reduces the strength of the back.

One of the functions of the reenforcing back is to hold the parts of the body together in case of fracture, which frequently occurs in service. The shoe is subjected to vibration in service and after the body fractures the effect of the vibration isconcentrated to a material extent upon the back along the line of fracture. Since the body usually fractures at or close to the attaching lug the vibrations of the shoe thereafter will be largely concentrated upon the back at probably its weakest section where it is recessed or upset at its side margins and reduced in width and strength. The recessing or upsetting of the marginal edges of the back has been necessary to provide sufilcient anchorage for the lug projections with the body of the shoe but has materially reduced the strength of the back where it is found in practice that maximum strength should be provided.

The object of my invention is to avoid the practice of recessing or upsetting the plate back at the attaching lug and to provide a brake shoe 7 with a plate back in which the marginal side edges of the back are continued without interruption or deformation beneath the attaching lug to preserve the strength of the back substantially 5 unimpaired at the attaching lug.

And a further object of the invention is to provide a brake shoe with a reenforce back imperforate at the bottom of the keyway of the attaching lug and having a projection of body metal 10 in the keyway and side projections connecting said keyway projection with the body of the shoe.

In the accompanying drawing illustrating a selected embodiment of the invention Fig. 1 is a side view partly in section of a brake 1:; shoe embodying the invention.

Fig. 2 is a top plan view of the reenforce back showing the outline of the shoe in broken lines.

Figs. 3 and 4 are transverse sectional views on the lines 3-3 and G i, respectively, of Fig. 1.

Fig. 5 is a fragmentary view partly in section showing projections from the body metal in the keyway of the attaching lug.

Fig. 6 is a sectional view on the line 66 of Fig. 5.

Fig. 7 is a detail view of an end portion of a reenforce back showing another form thereof.

Referring to the drawing, the body I of the shoe is generally made of cast iron and sometimes it is provided with chill sections and sometimes it has inserts of different kinds embedded therein. The reenforcing back 8 is made of a ductile metal plate which is embedded in the back of the body. This plate has cut-outs 9 to receive the body metal for anchoring the plate in the body. The center attaching lug comprises a lug strap I0 bent to form a keyway with its end portions ll pro-- jected through parallel longitudinal slots I2 in the back and bent inwardly against the underside of the back.

The marginal side edges E3 of the back are depressed providing a crowned central portion l4 therebetween. The crowned portion It lies in a surface above the surface of the depressed marginal edges of the back and is generally flush with the back of the body. These marginal side .edges of the back are not recessed or upset at the attaching lug but are continuous at the attaching lug and throughout at least the-central portion of the shoe and preferably throughout the length of the back. Nor is the back out out at the bottom of the keyway but it is left imperforate and the slots l2 extend lengthwise of the back and are of just suflicient width to receive the side portions of the lug strap. Therefore the width of the reenforcing back is maintained at and adjacent the attaching lug and the strength of the back is not reduced by recessing or upsetting the marginal edges of the back at the attaching lug.

Projections l5 of body metal are formed as usual at the sides of the attaching lug but these projections are enlarged at l6 by increasing their width so that they will extend beyond the planes of the sides of the body (Fig. 4) This enlargement in width of the projections provides ample anchorage of the projections with the body metal and avoids the necessity for recessing or upsetting the marginal side edges of the back at the attaching lug for this purpose. Therefore the width of the reenforce back may be maintained at the attaching lug without recessing or upsetting the marginal edges thereof and without reducing the strength of the back at the attaching lug where it is most needed for resisting the strains of vibrations in service after the body of the shoe fractures.

The projections may extend lengthwise of the shoe and beyond the edges of the lug strap, as

shown in Figs. 2 and 5, and this permits body metal to flow around the-edges of the lug strap and form a projection IT at the bottom of the keyway in the attaching lug, Figs. 5 and 6, if desired.

I prefer that the depressed marginal side edges of the reenforce back be continued to the ends thereof as shown in Fig. 2 but for some purposes it may be desirable to provide the back with fiat ends l8 as shown in Fig. '7.

My invention avoids the practice of reducing the strength of the reenforce back by recessing or upsetting the marginal side edges thereof at the attaching lug and preserves the width and strength of the back at the attaching lug. The slots l2 extend lengthwise of the back and do not materially reduce the transverse strength of the back. This result is made possible by increasing the width of the projections of body metal at the sides of the attaching lug whereby ample anchorage of .the projections with the body of the shoe is provided to prevent the projections from being broken off in the handling or service of the shoes. The projections I! in the keyway also add to the strength of the projections l6 at the sides of the attaching lug and increase the anchorage of the projections to the body of the shoe.

I do not intend to restrict the invention to the simple form of freight car shoe which has been selected for the purpose of illustrating and describing it; I appreciate the fact that the invention may be embodied in a variety of ways in different kinds of shoes; and I reserve the right to make all such changes and embodiments of and a center attaching lug, said plate having its marginal side edges depressed at the attaching lug and wholly enclosed within the body of the shoe.

2. A brake shoe having a body, a reenforce plate anchored to the body at the back thereof, and a center attaching lug, said plate having its marginal side edges depressed between the end portions of the shoe and at the attaching lug and wholly enclosed within the body of the shoe.

3. A brake shoe having a body, a reenforce plate anchored to the body at the back thereof, and a center attaching lug, said plate having its marginal side edges depressed and wholly enclosed within the body of the shoe at the attaching lug andthroughout the length of the back.

4. A brake shoe having a body, a reenforce plate anchored to the body at the back thereof, and a; center attaching lug, said plate having its central portion in one surface and its marginal side edges depressed in another surface and extending outwardly from the central portion at the attaching lug and wholly enclosed within the body of the shoe.

5. A brake shoe having a body, a reenforce plate of less width than the-body and anchored to the body at the back thereof, and a center attachinglug, the marginal side edges of the plate beingdepressed below the central-portion at the attaching lug and wholly enclosed within the body'of the shoe.

6. A brake shoe having a body, and a reenforce plate of less width than the body and anchored to the body at the back thereof, said plate having its marginal side edges projecting outwardly from the intermediate portion ofthe plate and depressed below said intermediate portion and embedded in the body of the shoe throughout at least the central portion of the back.

body of theshoe to solidly embed the depressed marginal side edges of the back opposite the lug strap and form ample anchorage of the projections with the body.

ROBERT B. POGUE.

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