USRE11885E - Brake-shoe - Google Patents

Description

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UNITED STATES c PATENT OFFICE.

WILLIAM -DLIRH'AIvI SARGENT, 'oF CHICAGO, ILLINOIS.`

BRAKE-SHOE.

SPECIFICATION forming part of Reissued Letters Patent No. 1 1,8845. `dated January 15, 1901. l Original NoI 643,734l dated February 20, 1900. Application for reissue filed November 19, 1900.l Serial No. 37,000.

To all whom it, mln/y concern: Y

Be i tkn own that I, WILLIAM DURHAM SAR-A GENT, a citizen of the United States, residing wheel, as has heretofore uniformly been the case. These and such other objects as may hereinafter appear are obtained by the devices illustrated in the accompanying drawings, in Which- Figure 1 represents a side elevation, partly in section, of brake-shoe embodyingmy inthereto.

ven tion. Figi. 2 represents a perspective view of oneend thereofpshowing the chill applied,

Similar letters of reference indicate th same parts in both figures of the drawings Referring by letter to the accompanyiw drawings, Azindicates the body of the brak shoe; B, prolongations at each end thereof C, the chilled portions'of the prolongationsk at each end of the shoe, (indicated by dotted' lines at the u pper end of the shoe,) aud Athe'chill forproducing the chilled pqitiods in the prolongations.

The dotted line E and E indicates thi'line of termination of the body of the brakeshoe as ordinarily constructed, so that the portion B projecting beyond 'this line at each'end of the shoe constitutes a prolongation of the shoe beyondjvhat is ordinarily providedthus, beyond the outermost points of support where the brake-head bears against the shoe (shown at :c in Fig. 1)-and aiordsa means for chilling the ends of the shoe from the back instead of from the front and'I sides of the shoe. It will be noted that the chill D does not embrace the sides of the shoe nor #extend around the steaming-face thereof, but

gation as generally triangular in shape, it` may be square, rounding, or of any other desired contor. The chill is set into the mold and the shoe is cast, that portion opposing the chill being hardened from the back inwardly toward the `bottom of the shoe, but not extendingto the wearing-face thereof, the intent-ion kbeing to leave about three sixteenths of an inch ofsoft cast-iron-say from the line a a to the wearing face of the shoe# between the chilled portion and the wearingface, so that whenL the shoe is 'rst put in service therewill be no contact with the Wheel of the chilled portion of the metal until. this soft-iron facing is worn down and the wearing-face of the shoe conforms tothe arc of the wheel-tread. As will be seen, 'however,

during the wear of' the shoe fromlthe point o, a to the point b b the area of chilled metal exposed on the wearingface of the shoe will be substantially uniform, and this uniformity will continue throughout the life of the shoe, as will be readily seen kby an examination of Fig. 1, which shows4 with approximate correctness the area of the chilled portion at the dd,andee.

successive points indicated by the lines c c,

from the back of the end of the shoe is of an entirely diiferent character from that which is produced by hardening the face of the shoe at the end or at any point intermediate tothe lends. In the case of my shoe the area of chilled metal at each end of the shoein contact with the wheel is practically uniform throughout the life of the shoe after the soft- Thechiu which is produced by hardening metal facing is worn away, and the' chill cominglfrom the back of the shoe, causing the greatest density immediately on' the back'` face of the shoe, with gradually-decreasingdensity as the chill penetrates the shoe, is

not. of a nature to injuriously'wear the wheel,

whereas 'in the case of shoes having chilled parts made from. the wearing-face of the shoe inwardly the area of the chilled section is fa greater at the commencementof wear and greatly diminishes as the shoe is worn, while the chill is hardest at the wearing-face' of the shoe and of a characteg calculated to injuri?l ously wear the wheel'.

Practically the entire body portion of my shoe coming in contact with the wheel is'an IOO area of soft cast-iron, and the area in con-A tact with the wheel at thev commencement of service is the .same as the Master Car-Builders standard cast-iron shoe.

5 My aim is to take a soft cast-iron brakeshoe and add metal at the ends, which may be so hardened from the back as to prolong the life of the shoe wit-hout injuriously affecting the wheel or diminishing the frictional Io power of thev shoe. f course, as before stated, the metal that is added to the end of the shoe may be either shaped as in the drawings or it may .be rounded or squared, so long as .the essential feature is retained-that of I its being chilled or hardened from the back, so that the chill merges into the soft cast-iron before reaching' the surface of the shoe exposed to wear against the wheel in com meneing service. 'Y i 2o WVhile I have shown in the drawings the prolongations as 4extending tangentially to the tread of the wheel, it is within the contemplation of my invention to form this extension concentric with the tread of the wheel,

2 5 ifdesi red, though the form shown in the drawings is preferred, because inthe commence- .ment of service the area of contact between the shoe and the wheel is the same as the lstandard' cast-iron shoe.

3o Myinvention possesses numerous advantages over any prior form of chilled castyiron shoe known to me, especially as regards the strength of construction, due to the fact that y the entire body of the shoe is composed of soft '-35 andvfstrong iron and the chilling of the prolongations at thefends does not in any way diminish the strength of the shoe` but rather by increasing the density of the metal inside of and contiguous to the chilled portion adds 4o to the strength of the shoe.- Thus it will be easily seen that the prolongations afford a place for chilling the ends without hardening any portion between the outermost points of support,-which would weaken the shoe and necessitate something extra. to add strengthas, for example, the steel plate com monly used in the back of such shoes as have their wearing-faces provided with chilled portions: It

is also to be observed that in shoes construct- 5o ed in accordance with myinvention the hardened part in the back ot' th-e ends will resist the com mon tendency of shoes to Wear wedgeshaped-that is, Athinner onone end than the other. The above advantages I have demonstrated by tests. Furthermore, I have found that it is possible by chilling from the back to obtain greater uniformity, from the fact that all of the surface of the shoe, as stated above, is of soft cast-iron until the shoe has sufereda wear, of about three-sixteenths of 6o an inch, while in all other forms of shoes con'- taining chilled sections there is either a portion of the chilled surface in contact with the wheel at the outset or the area of soft castviron in contact with the Wheel constitutes 65' only a part of the Master Car-Buildersstand-- ard arca for shoe-surface. With the characteristics of durability obtained from the chilled portion of my shoe I have greater strength, more friction, andgreater uniform- 7o ity of action onthe wheel than any other chilled shoe, and all of these results arise from chilling the back of the prolongation on each end of the shoe.

Having described my Ainvention, what I claim, and desire to secu re by Letters Patent, is- 4 1. A cast-iron brake-'shoe having triangular prolongations tapering from the back to the wearing-surface of the shoe at the ends 8o thereof and chill-hardened from the back, saidl chilled portions not extending to the wearing-surface of the shoe, substantially as and for the purpose described. r

2. A cast-iron brake-shoe having tangential triangular prolongationsat the ends thereof chill-hardened' from the, back, said chilled portions not extending to the wearing-face of the shoe, substantially as and for the purpose described. I 9o 3. A brake-shoe having prolongations at the ends thereofchill-hardened from the back, substantially as described.

4. A cast-iron brake-shoe having the portion between the outermost points of support of soft iron and provided with prolongations at the ends extending beyond said outermost 4points of support, said prolongations being chill-hardened from the back, substantially as and for the purpose described.

5. A east-iron brake-shoe having the por-l tion between the outermost points of support of soft iron and provided with prolongations at the -ends extending beyond said outermost points of support, the back of said prolongax05 tions being'chill-hardened and the wearingsurface -thereofsoft, substantially as and for the purpose described. h 6. A brake-shoe having tangential prolongations at the ends thereof chill-hardened no from the back, substantially as described.

WILLIAM DURHAM sARGENT.

Witnesses: v 1

PAULy SYNNEsirvli:1yr,4 v SAUL CARPENTER.'

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