US674255A - Metallic brake-beam. - Google Patents

Description

No. 674,255. Patented May l.4, l90l. T. M. BELL.

METALLIC BRAKE BEAM.

iAgpl-inahionfiled Dec. 13, 1899A (No Model.)

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. UNITED STATES PATENT OFFICE.

THOMAS M. BELL, OF PHILADELPHIA, PENNSYLVANIA.

METALLIC BRAKE-BEAM.

SPECIFICATION formingpart of Letters Patent No. 674,255, dated May 14, 1901.

Application filed December 13, 1899. Serial No. 740,194. (No model- To all whom it may concern.-

Beit known that I, THOMAS M. BELL, acitizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Metallic Brake-Beams, of which the following is a specification.

My invention consists of certain improvements in brake-beams such as are shown in the patent of G.Westinghouse, J r., No. 243,416, dated June 28, 1881, one object of my invention being to so construct such a brake-beam as to very materially increase its strength and especially its resistance to the strain caused by the movement imparted to the brake-shoes when they are pressed against the wheels, and a further object of the invention being to so construct the beam that it may be formed without stretching or compressing either of its members.

In the accompanying drawings, Figure 1 is a plan or top View of a brake-beam constructed in accordance with my invention. Fig. 2 is an enlarged transverse section on the line a a, Fig. 1. Fig. 3 is an enlarged transverse section on the line b b, Fig. 1; and Fig. 4 is a view of the beam, showing the first step in the manufacture of the same.

The brake-beam shown and described in the patent of Westinghouse before referred to consisted of a beam having an H crosssection and having one of its flanges severed from the web and bent outward so as to form the V-shaped member of a truss of which the Web and remaining flange of the beam formed the other member, which was straight, the integrity of the beam at the ends being undisturbed and a strut being interposed between the two members of the truss at the center of the beam, upon which strut was mounted one of the levers of the brake mechanism. The objection to a brakebeam of this character is its lack of strength, the bent member of the truss being deficient in this quality because of its defective rectangular cross-section and because of the stretching or piecing out of the metal rendered necessary by the bending of the same into V form. A beam of this character is especially weak in its resistance to strains transverse to the pull upon the beamthat is to say, to such strains as would be caused by the movement imparted to the brakeshoes when they are forced hard against the rims of the wheels and have a tendency to move with the same. In order to overcome these objections, therefore, I form a truss, each member of which comprises a web and flange that is to say, is T-shaped in crosssectionand by preference I so form the truss that no stretching or compression of either member of the same is necessary.

The preferable method of procedure is to take an I-beam-such, for instance, as shown at 1 in Fig. 4-this beam being of the proper length and having wide flanges, and then to form in the center of the web a slot or incision 2, extending to within the required distance of each end of the web, the preferable method of forming the slot being to punch a narrow strip from the center of the web, so that the slot will have rounded ends, as shown in Fig. 4. By suitable means the two portions of the beam are then drawn or forced apart, as shown in Fig. 1, so as to produce a truss having two bent members 3 and 4:, each consisting of a flanged web, these two members uniting at the I-shaped ends 5 of the beam. To each of these ends 5 of thebeam is riveted or otherwise suitably secured a head 6 for the reception of the brake-shoe, and between the two members 3 and 4 of the truss at the center of the beam is interposed a strut 7, composed of two parts secured together by rivets 8 or other available fastenings, this strut having end portions engaging with the members of the truss and having a transverse slot 9 for the reception of the brake-lever and an opening 10 for receiving the pivot-pin for said lever. Each member of the truss comprises a flanged rib, which is much stronger than a simple bar of rectangular cross-section, such as the V-shaped member of the truss constituting the Westinghouse beam, before referred to, and as the flange lies in a plane transverse to the direction of pull upon the beam the truss member has its greatest dimension in said plane, and hence opposes a rigid resistance to the bending of the beam, such as might otherwise be caused by strains in that plane caused by the action of the wheels upon the brake-shoes after the latter have been pressed firmly into contact with the rims of the wheels.

In forming the truss an equal amount of bend is imparted to each member of the same, the opposite ends of the beam approaching each other as the beam is shortened, and no stretching or compression of either member of the truss results.

Having thus described my invention, I claim and desire to secure by Letters Patent A metallic brake-beam consisting of a beam of Lshaped cross-section having the central portion of its Web split or slotted so as to form two members each comprising a Web and I u v v o name to this specification in the presence of two subscribing Witnesses.

THOMAS M. BELL.

Witnesses:

F. E. BECHTOLD, Jos. H. KLEIN.

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