US685023A - Brake-shoe. - Google Patents

Description

no. 685,023. 'Patented oct. 22, ism. woLHA T n.

BRAKE S (Applcafion med Mar. 18, 1901.)

- (No Model w 2:7 I (l y Millor/myx* NrTnn STATES PATENT BRAKE-SHOE.

SPECIFICATION forming part of Letters Patent No. 685,023, dated October 22, 1901. Application filed March 18, 1901i Serial No. 51,679. (No model.)

T0 all whom it may concern:

Be it known that I, BENJAMIN WOLHAUP- TER, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Brake-Shoes; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in brake-shoes of that class in which the wearing-faces are compound iu character and composed in part of soft or quick-wearingsections and in part of hard or slow-wearing sections and wherein the hard or slow-wearing sections are employed to resist wear, thereby to prolong the life of the shoe.

The invention consists in the matters hereinafter described, and pointed out in the appended claims.

Brake-shoes having their wearing-faces composed of hard and soft wearing-sections have heretofore been made by the employment of slow-wearing inserts, and in the case of shoes consisting of a single casting also by providing therein chilled metal sections, which are harder and therefore more durable than the unchilled parts.

My invention is applicable to brake-shoes made in both of the ways described, and it has relation more particularly to the arrangement of the hard-metal sections with respect to the soft or quick-wearing parts.

As will be readily understood by those familiar with the art, brake-shoes are attached to the brake beams or support at the middle of the length of the shoe, so that pressure for holding the shoe in contact with the wheel is applied to the shoe at a point about midway of its length. In the use of shoes provided with hard and soft metal sections it is found that the shoes are liable to wear more rapidly at one end than at the other and that the life of the shoe is much shorter than would'otherwise be the case through such unequal Wear, it being obvious that the shoe will be no longer tit for use when the metal body thereof has become worn through or has become very thin at one end of the shoe.

In carrying out my present invention I provide in the shoe hard or slow-wearing sections, which are uniformly disposed or arranged with respect to the point at which pressure is applied to the shoe or the center of oscillation thereof, and I arrange said hard sections obliquely and in such manner that the edges thereof exposed at the wearing-surface of the shoe shall be nearer together at such wearingsurface than at the rear or outer surface thereof. The result of this construction is that as the face of the shoe wears away the surfaces of such hard-metal sections which are exposed to the wearing action of the wheel gradually move outward, so that when the shoe is worn out the said hard-metal wearing surfaces Will be much farther apart than when the shoe is new. This arrangement of the hard sections insures uniform wear or equalization of the wear at opposite ends of the shoe, for reasons which will be understood from the following: If there be any tendency to unequal Wear, such as often exists by reason of inequality in the metal of the shoe, from the fact that the brakebeam is so moved as to press the shoe upwardly or downwardly instead of directly toward the wheel or from other causes, as soon as such unequal wear begins the wearing-face of the oblique slow-wearing section at the end of the shoe Where the greater amount of wear occurs will recede or move outwardly from the center line of the shoe or point of support, so that it will be at a greater distance from said center line than'that of the slow-wearing surface at the opposite end of the shoe or the one where the less wear occurs. The hard wearing-surface, which is at the greater distance from the center line or point of support, will then obviously be pressed with less force against the wheel by reason of its greater distance from the point of support,while the hard Wearing-face,which is nearer the said center line, will be pressed with greater force against the wheel, and the result will be that more rapid wear will take place on the hard wearing-face nearer the said center line and the latter will be more rapidly worn away until it recedes from the center of the shoe so far as to be at the same distance therefrom as is the other hard surface.

Obliquely-disposed hard or slow-wearing ICO sections may be provided in the shoe either in the form of hard-metal inserts or in the case of a cast cast-iron shoe by chilling the metal in a manner to provide such oblique or inclined sections.

My invention may be more readily understood by reference to the accompanying drawings, wherein- Figure l is a View in central longitudinal section of a brake-shoe embodying my invention. Fig. 2 is a face view thereof. Fig. 3 is a similar section showing oblique hardmetal sections formed by chilling in the construction of a cast-iron shoe. Fig. il is a detail section showing one end of another form of shoe embodying my invention, the same having slow-wearing sections attached to its ends. Fig. 5 is a sectional view of the same taken upon line 5 5 of Fig. 4r.

As shown in said drawings, A indicates the casting, constituting the body of the shoe, which is provided at its rear or outer face with the usual centrally-arranged projection or lug A', having an opening a, through which is inserted a key for holding the shoe to the brake-head, by which it is supported. The body A is also shown as provided at its ends with transverse projections A2 on its rear face, adjacent to which are seats a to receive the ends of the said brake-head.

The shoe shown in Figs. l and 2 is of that kind consisting of a soft or cast metal body with hard-metal inserts B B. Said inserts B extend transversely across the face of the shoe and are disposed obliquely orin oblique planes, so that their edges exposed at the wearing-face of the shoe are nearer together than their edges adjacent to the outer or rear face thereof. As shown in said Figs. l and 2, the inserts B are of uniform thickness or have parallel faces and are located as close as practicable to the ends of the shoe.

In Fig. l the dotted lines w w indicate the wearing-face of the shoe after it has been worn to a considerable extent and under normal conditions or when the wear is equal at both ends of the shoe. It will be readily seen that under normal conditions of wear the faces of the hardmetal inserts B B which are exposed at the wearing-face of the shoe will gradually recede from each other or from the point of support of the shoe as the latter wears away. In said Fig. l the dotted lines w' w indicate the face when the wear is unequal or greater at one end of the shoe than at the other. From the location of this line it will be seen that even when the unequal wear is slight the hard-metal wearingface of the insert B at the end of the shoe which is worn away to the greatest extent will be at a considerably greater distance from the center line of the shoe than the corresponding wearing-face of the insert at the other end of the shoe. It will be also observed that by reason of this greater distance of the hardmetal wearing-face at the end which is most worn the latter will be pressed with less force against the wheel by the pressure of the brake beam or support acting on the lug A or at the center line of the shoe than will the corresponding hard wearing-face at the opposite end of the shoe. Manifestly the degree of pressure exerted by the two inserts will correspond with the differences in pressures which would be exerted by lever-arms of un equal lengths or of lengths corresponding to the distance between the center line of the shoe and the two hard wearing-faces. As a consequence of the greater pressure exerted upon the hard wearingsurface, which is. nearer the center of pressure, the latter will tend to wear away more rapidly and there will be a constant tendency to uniformity of wear or to maintain the wearing-face pa allel with the original contact-face of the shoe. In practice, thereforeJ a shoe constructed as described will always present a Wearing-face substantially like that indicated by the dotted. lines w yw.

Fig. 3 shows a construction wherein the body of the shoe is of cast metal and is provided with chilled hard-metal sections E, the ends of the shoe being` provided with oblique end faces A3, which make obtuse angles to the wearing-face of the shoe. The chilled sections are in this instance formed by casting the oblique end surfaces A3 thereof in contact with the obliquely-arranged chills. Obviously the result of the presence of the chilled-metal sections E, arranged obliquely in the manner shown, is the same as that obtained by the hard-metal sections B 13. (Shown in Fig. 1,)

In order that the original bearing or con-- tact face of the shoe may be of full `or the usual length, the ends of the shoe in this construction are extended beyond the projection A2 at the rear face of the shoe, so that the oblique chilled parts E project beyond the usual wearingsurface. This affords a very simple and desirable construction, as it enables the oblique hard-metal sections to be provided without increasing the cost of construction over that of a plain cast-metal shoe except for the expense of chilling the ends of the shoe inwardly from the oblique face of such ends.

The slow-wearin g sections are herein shown as arranged at uniform distances from the center of the shoe in order to obtain equal or uniform action thereof at both ends of the shoe; but the same result will manifestly foln low if one of the sections be located nearer the center of the shoe than the other and at the same time be made thicker in order to afford an increased resistance to wear proportionable to its distance from the said cen ter. The two slow-wearing sections are theren fore in either case arranged symmetrically with respect to the center of the shoe in the sense that theyare so disposed and constructed as to afford equal resistance to wear under IOO IIO

a pressure acting on the center of the shoe and tending to press the same against the Wheel.

Obliquely-arranged slow-wearing sections corresponding in operation and function with the inserts B B (shown in Figs. l and 2) may be provided by securing such sections to the extreme ends of a shoe. A construction of this kind is shown in Figs. 4 and 5, whereinv F indicates a section of slow-wearing material forming, in effect, an extension of the body of the shoe and disposed obliquely with respect to the wearing-face of the shoe. Such a section may be attached to the end of the shoe by any one of several different expedients, the attaching means shown consisting of a ribfon the inner face of the section F, which rib is provided with a plurality of apertures f', Fig. 5. The said rib intertits With a groove in the oblique end of the body of the shoe, and it may be held therein by parts of or upon the body of the shoe arranged to pass through or engage said apertures. As shown in the drawings, the body of the shoe is cast upon the insert F, and t-he metal of said body passes through the said apertures f', so as to firmly unite the parts.v

I claim as my invention-ai 1. A brake-shoe composed in part of soft or quick-Wearin g material and in part of hard or slow-Wearing material, the hard Wearing maL terial being disposed in symmetrical relation to the center of the shoe, said sections having their inner or Wearing faces nearer the point of support of the shoe than their parts adjacent to the outer part or back of the shoe.

2. A brake-shoe composed in part of soft or quick-Wearing material, and in part of hard or slow-Wearing material; the hard Wearing material being disposed in tWo similar sections at points equidistant from the point of support of the shoe, each of said sections being disposed obliquely and inclined in such manner that their inner or Wearing faces at the Wearing-faces of the shoe are nearer together than their parts which are adjacent to the outer face or back of the shoe.

3. A brakeshoe composed in part of soft or quick-Wearin g material and in part of hard or slow-Wearing material, the hard Wearing material being disposed in tWo similar trans verse sections arranged transversely of the shoe at points equidistant from the center of support of the shoe, each of said sections having parallel side faces and being disposed obliquely with their Wearing-faces nearer together than their parts adjacent to the outer face or back of the shoe.

4. A brakeshoecom posed in part of quick- Wearing material and in part of slow-Wearing material, said shoe having at its ends oblique faces making obtuse angles with the Wearingface of the shoe, and the shoe being chilled at such oblique faces to form obli que sections ot' slow-Wearing material.

In testimony that I claim the foregoing as my invention I affix my signature, in presence of two Witnesses, this 14th day of March, A. D.

BENJAMIN WOLHAUPTER. Witnesses:

CLEMANs R. STIOKNEY, BERTHA A. PRICE.

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