‘ Feb. s, 1938. ' J, G, HAWLEY 2,107,295 . BRAKE LINING AND METHOD OF‘ MAKING SAME Filed Aug. 26, 1933

OUTER suBFAcz FORMED 0F YARN IMPREGNHTED WITH GRAPH/TE.

GRAPH/TE l/V/PE'EGNATED F./ 05' I YARN.

GRAPH/TE IMPREGNATED ' YARN_

Jésse ‘Gulfa wlethy, 3;,” W m Patented Feb. s, 1938 2,107,295

i STATEs PATENT OFFICE ‘2,101,295 “BiiAKE-LINING METHOD or MAKING .~Je'sse'v/G. HawIey, Painted PostrN. Y., assignor to Hawley-Jones Corporation, Riverside, N. Y., ' - a corporation of New York ' ' . Application August 26, 1933, SerialVNo. 687,009

. > .. , 9' Claims. (Cl. 139-420) This invention relates‘ ‘to they art of‘brake pregnated yarn adapted for use in accordance linings. , \ " ' ‘ ' with my invention. ' Most prior brake-linings with which I am According to a preferred embodiment of my familiar have generally been "made of uniform invention, a brake lining of the woven, asbestos 5 construction on both sides, thus being adapted to type is made by impregnating asbestos yarn be- 5 have the same coe?icient of friction on both fore weaving with a predetermined amount of surfaces.’ A few brake linings, however, which graphite. and then manufacturing the actual are intended tohave frictional contact on only brake lining by weaving the graphite impreg one surface, have been provided with a non nated yarn into only one-surface of the resulting 10 operatingwsurface of different character than brake lining, after which the brake lining is 10 the operating surface as, for instance, with wire ?nished in the usual, or any desired,_way, in mesh on the side that’v goes next to the shoe to cluding the friction imparting treatment near which it is to be riveted. the end of the manufacturing operations. In I have discovered, however, that when brake other words, in my preferred embodiment, the 15 linings of the .?rst‘rnentioned type are used as inclusion of the graphite on one side of the brake l5 a floating lining in brakes, ‘for example such as lining reduces the coefficient of friction. on that is disclosed in my application Serial No. 590,481, side of the lining, that would otherwise be im ?led February 2, 1932, that the braking action parted to it by the subsequent manufacturing is not as positive as is desired unless precau operations, and provides a brake lining with a 20 tions are taken to secure a uniform coe?icient of. differential coefficient of friction on opposite 20 friction between the brakeshoe and the inner operating surfaces thereof. surface of the brake lining, and the brake drum By properly proportioning the amount‘ of and the outer ' surface of the brake lining. graphite used, the resulting brake lining, when Furthermore, brake linings of the second type ' utilized as a ?oating or unanchored brake lining 25 mentioned above are not adapted for use as between two relatively'rotatable members‘ of a 25 ?oating linings where both surfaces of the brake brake or shock absorber, will have the same de lining are intended to function as friction'creat gree of slippage on both operating surfaces. . ing means. ' The amount of the graphite treatment is It is therefore an object of this invention to varied according to the size of the drum, the 30 provide a new and improved brake lining. load to which the brake or shock absorber is to 30 It is another object to provide a_brake lining be subjected, and the particular friction impart with a different coe?icient of friction on oppo ing treatment used in manufacturing the brake‘ site operating surfaces thereof. lining. > It is a further object to provide a brake lining 'In the preferred embodiment of my invention 35 with a relative predetermined coefficient of fric as applied,.for example, to a brake of the general 35 tion which will be'di?erent for both operating type disclosed in my aforesaid application, the surfaces thereof. graphite treated yarns extend thru substantially It is also an object of this invention to provide the outer half of the thickness of the brake a brake lining with a different coefficient of fric lining and the amount of the graphite treatment '40 tion on opposite operating surfaces thereof in is so proportioned as to get a slippage of about 40 order to achieve a uniform coefficient of friction one-half of the drum speed when the'brake is in the actual operation of the brake lining as applied. used in a brake. Without desiring to be limited thereto.. my With the above and other objects in view, present belief of the theory of the operation of 4.; which will be apparent as the description pro my improved brake lining is as follows: 45 ceeds, I have set forth my invention in the fol When the lining is bent to conform to the lowing speci?cation, and have described- and shape of a round brake drum, the inner surface illustrated one embodiment thereof by way of of the brake lining occupies a lesser area than 50. exampleIn the butaccompanying not as a limitation. drawing, Figure 1 > illus the outer area of the brake lining. Hence, if the coef?cient of friction on both sides of the 50 trates a perspective View of a section of brake' brake lining is the same, the resulting operation, lining ‘embodying my invention; Fig. 2 illustrates in the application of the brake, is that the greater a transverse section therethro-ugh on line 2——2 of area of the'outside of the brake lining causes the Fig, 1; and Fig. 3 is a perspective view, on a brake lining to tightly engage the inner surface 55 greatly enlarged scale, of a piece of graphite im of the drum, in the case of an internally ex~ 2 2,107,295 panding brake, and to slip with respect to the ments of this invention may be made without de ‘brake shoe. This prevents the obtaining of the parting from the spirit thereof, it is to be under maximum uniform braking action, which is stood that I do not limit myself to the foregoing usually desired. This unequal coe?icient- of fric embodiments or description except as indicated tion in the actual operation of a brake is over in the following patent claims. come by reducing the coeii‘icient of friction of I claim: \ the outer side of the brake lining, in the case of l. A brake lining provided on one side thereof ‘an internally expanding brake or a circular type with graphite to reduce its coefficient of friction shock absorber, so as to compensate for the on that side, the other side of said lining being 10 10 greater area of the outer surface as compared free of said material. > with the area of the inner surface. The result 2. A brake lining provided on one side thereof is a uniform coe?‘icient of friction in the result- I with a graphite treated woven asbestos yarn to ing brake or shock absorber and the attaining of reduce its- coe?lcient of friction on that side, the other side of said lining being free of said the maximum braking action for a given con 15 15 struction. ‘ material. . It. will be apparent that the selective coef 3. A brake lining provided on one side thereof ficients of friction on the two sides of my brake with a graphited woven asbestos yarn to‘ reduce lining can be obtained in various other ways its coe?icient of friction on that side, the other side of said lining being free of said material. than by the graphite treatment disclosed here 20 20 _ in, as by. the impregnation of the yarn with other 4. The method of making brake lining having materials, or by the impregnation of the outer a different coet?cient of friction on opposite surface of the brake lining with materials which operating surfaces thereof which comprises treat ‘reduce its coemcient of friction, or by the im ing a portion of the material to be used in the manufacture of the brake lining with a material pregnation of the inner surface of the brake lin 25 -25 ing with materials which increase its coeificient to alter the coe?icient of friction to be imparted ‘of friction. Similarly,_the difference in the co to it, manufacturing said brake. lining from both ’e?icient of friction may be attained by other treated and untreated material but using the methods than impregnation of the unwoven yarn, treated material on only one side of the brake ' lining, and treating both surfaces of the brake or the resulting woven surface, as by a dipping 30 30 or a spreading action. lining with the same friction imparting oper It will also be apparent that in constructions in ations. _ ' ‘which there is an external contraction, instead 5. The method of claim 4, in which the treat of an internal expansion, the opposite situation ‘ment ?rst given involves an impregnation. is encountered, and the desired result in such a 6. The method of claim 4, in which the treat 35 case is obtained by reversing the sides of my - ment ?rst given involves the impregnation ofv improved brake lining when same is assembled yarn with graphite. in such a modified construction. 7. The method of making a brake lining hav As indicated, a preferred use of my brake lin- ‘ ing different coe?icients of friction on opposite ing is in the general typeof brake disclosed‘in operating surfaces thereof which comprises treat my aforesaid brake application, but my inven ing a portion of the material to be woven with a 40 . tion is of general application and is not limited non-metallic material to alter its final coeffi thereto, as it is applicable to either internally cient of friction prior to manufacturing it into expanding or, externally contracting brakes hav brake lining, and manufacturing said material ingi?oating or unanchored linings, and to shock into brake lining in conjunction with untreated 45 absorbers of. the‘ circular type provided with a material with the treated material on only one ‘floating lining. side of said brake lining. , , It is also a part of my invention to provide a 8. A brake. lining formed Of woven material >brake lining with different coefficients of friction provided with different coe?icients of friction on on" opposite operating surfaces thereof for any opposite operating sides thereof, one of said sides containing graphite and the other side being 50 50 other type‘ of construction in which same might be desirable. . free thereof. , ' ' Q Also, although I have disclosed by invention 9. A brake lining of woven asbestos yarn pro herein asapplled ‘to a woven asbestos yarn, my vided with different coe?icients of friction on op posite operating sides thereof, one of said sides invention is not limited, thereto and may be ap 55 55 plied to many other types of brake lining,-such as containing graphite and the other side being free moulded lining. ' thereof. As many apparently widely different embodi JESSE G. HAWLEY.