US2948360A - Brake shoe - Google Patents

Description

Aug. 9, 1960 C. R. LUPTON BRAKE SHOE Original Filed Feb. 21,

INVENTOR.

624/0406? ZZ/P/dA/ v ATTORNEY States Aviation Corporation, South Bend, Ind., a corporation of Delaware Continuation of abandoned application Ser. No. 145,365, Feb. 21, 1950. This application April 6, 1955, Ser. No. 499,545 p '3 Claims. or. '188234) The present invention relates to brake shoe construction, and its primary purpose is to provide a brake shoe having readily separable web and rim elements. The brake shoe is constructed and arranged to be readily reduceable to the component parts when servicing is required, albeit such parts are normally firmly held together, or retained in assembly, by reliable holding or locking means. This application is a continuation of my copending application, Serial No. 145,365, filed February 21, 1950, and now abandoned.

The present invention constitutes an improvement over the invention disclosed in the House Patent No. 2,598,545, in that it is simpler in construction, easier to produce and consequently less costly, and more reliable in operation. The component parts making up the assembly of the present invention can be made by conventional mass production methods to be interchangeable, thereby providing for ease of original assembly and of replacing worn parts.

The principal differences between the construction of the present invention and that of the Hous patent reside in the means for holding the shoe in assembled condition and the method for assembling the shoe. The disclosure of the House patent used bar stock to fabricate the holding means, and in production it was found that the close tolerances required impeded production as well as raised the cost of the finished product to a relatively high figure. The present inventionutilizes a construction which is easily assembled; lends itself to ordinary-manufacturing processes; costs less to produce; and is reliable in operation.

The brake shoe has been developed so that superior shoe assembly methods may be utilized. The shoe structure lends itself to an easier, simpler, and more eflicient way of bringing the components together and holding them together.

The advantages of a detachable rim shoe can only be realized if the rim and web are easily put together and held together. The two-piece shoe must also lend itself to field replacement and, therefore, the shoe-assembly method must not require costly or elaborate tools.

Other objects and features of the invention will become apparent from a consideration of the following description which refers to the accompanying drawings, wherein:

Figure 1 is an exploded view of the component parts of an embodiment of the present invention;

Figure 2 is an enlarged side elevation of the resilient leaf spring;

Figure 3 is .a fragmental bottom plan view of one end of an assembled brake shoe showing the leaf spring in place;

Figure 4 is a side elevation of the same and illustrated in Figure 3; and

Figure 5 is a plan view taken at right angles to Figure 3.

Referring to the drawings, and more particularly to Figure 1, the three parts are the detachable rim carrying a lining =12, the separately formed strengthening web Fee 2 14, and the resilient, or spring element 16 used to retain the rim and web in assembled relationship.

The rim 10 has three spaced slots 18, 20, and 22 along its longitudinal center line, the slots being provided for the purpose'of receiving complementary projections 24, 2'6, and 28, respectively, formed on the web 14. Referring to the left end of the rim as the fforward end, it will be observed that the forward, preferably slanted edge of slot 22 serves as a surface of engagement 30 and will be engaged by a hook-shaped side 32 on the projection 28.

The i-ear or right, end of the rim 10 is turned inwardly to provide a laterally-extending ledge 34, which serves as a support, or seat, for the resilient retaining element 16.

The rim 10 and web 14 are separately formed stampings, the web 14 having an arcuate surface 36 adapted to engage theinner longitudinal center line of the rim 10. With the rim and web assembled, the hook-shaped surface 32 prevents relative longitudinal or circumferential movement thereof in one direction while concurrently preventing radial separation of the web from the rim. in assembling the rim and Web, the inclined surface 32 also acts to bring the rim and web into tighter radial engagement as the web is urged to the left, or forward end of the rim.

The right end of the web adjacent the ledge 34 is provided with a shallow rectangular shaped notch 38 hava length slightly larger than the width dimension of spring element '16. The purpose of this notch 38 is to keep the spring :16 from working out of radial position; however, any means for holding the spring in place may be used and in some instances, a part of a brake assembly which lies near the end of ledge 34 may serve. the purpose.

The other details in the shape of the web are conventional features of brake shoes. The invention is, of course, applicable to brake shoes for various types of brakes, without limitation to any particularbrake arrangement. The several holes in the illustrated brake web are provided for such purposes as retaining theends of shoe return springs, locating shoe holddown devices, and providing a bearing for an anchor link pin. The details of the web shape, except as to the particular features previously noted, are dictated by the requirements of the brake assembly in which the shoe is to be mounted.

The spring element 16 consists of a semielliptic plate spring fabricated of spring steel or the like, preferably having a square or rectangular cross section. A locking depression or transverse indentation 40 is formed in the outer side of this spring 16 between its ends to straddle the thickness of the web 14. While this spring 16 is in assembled position, this depression 40 straddles the end edge of the web 14 therebyholding the spring 16 against endwise or longitudinal movement. With the spring so assembled, it is under a load tending to flatten it, and it, therefore, urges the web and rim into tighter radial engagement through the cam action of the hooked-shaped projection 32. While it is preferred that spring element 16 have a rectangular cross section, it is to be understood that any cross-sectional shaped stock may be used so long as some provision is present in the spring element design to hold it against accidental rotation or movement out of the shoe assembly.

In assembling the shoe, the web is first slipped into position on the rim by inserting projection 24 into its slot 18 and then bringing the other projections into their respective slots. The single remaining step is to assemble the spring element 16. This is accomplished by inserting one end of the spring 16 into the space between the right end of the web 14 and the ledge 34, and using a hammer or the like, to force the spring longitudinally product.

into place where the depression '40 straddles the thickness of the web 14.

Forcing the spring laterally between the web and rim members causesdeflection of the mid portion of the spring, which deflection causes loading of the spring.

The spring loading causes relative circumferential movement of the web and rim members, thereby causing them to be brought into intimate contact by reason of the hook shaped surface 32 on projection 28 at one end of the shoe.

In disassembling the shoe, a blunt screwdriver blade or the like is used to drive the spring '16 endwise from its assembled position. from the web while the brake shoe assembly is mounted in a brake, a suitable tool is inserted into one of the spring holes 42 to withdraw the spring from the assembly. This procedure being so simple, it becomes obvious that the entire diassembling and reassembling operation can be performed in a matter of a few seconds. 7

With this particular brake shoe design, ordinary manufacturing tolerances are permissible to produce a reliable This conduces to economy of manufacture as well as use, since in servicing brakes because of worn lining or damaged rims, a factory-lined rim may be substituted for the unserviceable one. The cost of the lined rim being relatively low, the user gets the benefit of lower charges for service labor and lower cost of manufacture.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangements of the parts may be made to suit requirements.

I claim:

1. A T-section shoe comprising a rim and web having spaced slots and projections respectively, said slots removably receiving therein corresponding projections, one end of said rim being turned inwardly to provide a flat laterally-extending ledge, at least one of said projections having a portion which cooperatively engages a portion of its slot to cause the web and rim to be brought into tighter engagement as the web is urged toward the end of the rim remote from said ledge, the end of the web adjacent said ledge being notched, and a resilient memher for holding the web and rim in engagement comprising a semielliptic plate spring element of rectangular cross section, a transverse depression having a width substantially equal to the thickness of the web formed in the outer side of said spring element between the ends thereof, said spring element being inserted between the end of said web and said ledge with the depression straddling said web in the notched portion thereof, said spring element exerting a force tending to urge the rim If it is vdesired to remove the rimand web in opposite directions whereby the rim and web are brought into tighter engagement.

2. A T-section shoe comprising a rim and web having spaced slots and projections respectively, said slots removably receiving therein corresponding projections, one end of said rim being turned inwardly to provide a flat laterally-extending ledge, at least one of said projections having a portion which cooperatively engages a portion of its slot to cause the web and rim to be brought into tighter engagement as the web is urged toward the end of the rim remote from said ledge, and a resilient member for holding the web and rim in engagement comprising a plate spring element having a raised center 3.v A brake shoe comprising a rim, a strengthening webwhich is perpendicular to the rim and which detachably engages the inner side of the rim, an inwardly projecting ledge formed on one end of said rim, one end, of the web adjacent said ledge being notched, inter-' locking means formed at the other end of said web and rim to hold the web and rim in assembled relation while they are urged lengthwise one with respect to the other,

and a resilient member for holding the web and rim in engagement comprising a semielliptic plate spring element of rectangular cross section, a transverse depres-. sion having a width substantially equal to the thickness of the Web formed in the outer side of said spring element between the ends thereof, said spring element being inserted between the end of said web and said ledge with the depression straddling said web in the notched portion thereof, said spring element exerting a force tending to urge the rim and web in opposite directions whereby the rim and web are brought into tighter en gagement.

References Cited in the file of this patent UNITED STATES PATENTS 2,139,409 Hunter Dec. 6, 1938 2,598,545 House May 27, 1952. 2,626,020 Keller Jan. 20, 1953 FOREIGN PATENTS 910,765 France Feb. 11, 1946 I

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