US996584A - Trussed-beam construction. - Google Patents

Description

J. J. HOFFMAN. .TRUSSED BEAM CONSTRUCTION. APPLICATION FILED JUNB29,1910.

Patented June 27, 1911.

INVENTOR.

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WITNESSES.

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JOHN J. HOFFMAN, OF NEW KENSINGTON, PENNSYLVANIA, ASSIGNOR TO PETER H. MURPHY, OF PITTSBURG, PENNSYLVANIA.

TRUSSED-BEAM CONSTRUCTION.

Specification of Letters Patent.

Patented June 2'7, 1911.

Application filed June 29, 1910. Serial No. 569,455.

To all whom it may concern:

Be it known that I, JOHN J. HOrFMAN, residing in New Kensington, in the county of Westmoreland and State of Pennsylvania, have invented a new and useful Improvement in Trussed-Beam Construction, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

This invention relates to truss beams more particularly to brake beams of this type, and its primary object is the provision of a construction in which the connection between the tension and compression members is such as to secure the maximum efficiency with great simplicity of form.

With the above object in view I aim to prevent the conversion of the enormous operative stresses, to which these beams are sub jected, into leverage tending to deflect and buckle the beam with consequent impairing of the brake efficiency. This weakness, this tendency to deflection, finds a strong example in truss brake beams in which the ten ion member passes from the compression member substantially at a point intersected by the plane of the inner face of the brake shoe head, or in other words, where parallelism is observed bet-ween the tension and compression members in their passage through and for the full, or substantially full width, of the brake shoe head. Such construction not only places the brake shoe heads, at each end of the beam, outside of the truss formed by the tension and compression members, but also in some cases causes the tension member to draw across the inner corner of the beam socket of the brake shoe head. Consequently, under service application, torsional strains are thrown on the brake heads, whi h tend toward backward cambering or deflection of the beam at or near the ends.

The above mentioned difliculties are obviated by providing in my improved beam a construction in which the strains thronn on the brake heads are converted into tensile strains which are taken up and carried by the tension member in straight lines substantially directly from the center of each shoe head to the base ofthe strut.

Further objects of my invention are to provide a construction which may be readily assembled and in which the tension and compression members may be interlockingly hold together against relative longitudinal movement without special fastening means; the provision of a beam in which the brake shoe heads may be removed and replaced without disturbing the truss between the compression and tension members; to provide novel means of direct attachment of the brake shoe heads to the ends of the beams; and to provide other details of construction, as will be hereinafter more fully described.

I will now describe my invention so that others skilled in the art to which it appertains may understand and construct the same, referring to the accompanying drawings in which I have shown my invention as applied to'a brake beam. It will be apparent, however, that my invention is equally applicable to body and truck bolsters.

Figure 1 is a plan view, showing one-half of a brake beam embodying my invention, the terminal portions of the tension and compression members, and also the brake shoe head being in section; Fig. 2 is an end view of the beam, the beam hanger showing in connection therewith being cross-sectioned; and Fig. 3 is a fragmentary perspective view of an end portion of the tension member.

In describing my invention, the reference numeral 2.. indicates the compression member, 3 the tension member, 4 the strut-bar or king-post, and 5 a brake shoe head carried by the respective end of the beam.

While it will be apparent that my invention may be applied to beams having ten sion and compression members of various cross-sectional shapes, I have shown in the accompanying drawings as the preferable embodiment thereof, the compression member as being of a flanged construction and the tension member as taking the form of a strap. The strut may be of any suitable form. The compression member is of a well-known type, being arranged with the web 6 disposed vertically and the flanges 7 projecting forwardly so as to receive the ends of the tension member 3 rising at each side from its seat in the base of the strut in the usual manner.

In my invention each end of the tension member is provided, preferably by forging, with the head portion 8, which is provided with a fiat face 9, which is adapted to be brought into engagement with the inner face of the web 6 of the compression member, as

shown in Fig. 1. Carried by the head 8 and outstanding from the face 9 is the lug 'or boss 10, which is adapted to be received by the suitable aperture, or opening 11, formed in the web 6, when the face 9 has been brought into abutment therewith, as above mentioned. From the lug 0r boss 10 the tension member 3 departs from the compression member obliquely substantially from the center of the brake shoe head 5 downwardly in a straight line to its seat in the base of the strut 4.

The brake shoe head 5 maybe surfaced .to receive any standard type of shoe, such as a 'Christy or Collins shoe, and is provided with a suitable socket 12 for the rec-epti'on oi? the conjoined ends "oi the tension and compression members. This socket 12 preferably takes the cross=sectional outline form of these united members, the head having the inset portion 13, which abuts against the forward face of tension member 3, and the lugs or shoulders 14 which overhang the back face of the compression member '2 and which cooperate with the inset portion, or lug 1 3, to hold the ends of the tension and compression members in interlocked position, when the head is placed in position on the beam.

It will be seen that the mouth 18 of the socket or opening of the brake shoe head is somewhat flared. The purpose of this is to permit the tension member to depart from the compression member, as stated above, at a point substantially central of the brake head without drawing across or hearing upon the corner, so to speak, of the head in a manner to set up leverage or torsi'on'al strains at the end of the beam.

The brake shoe head may be cored out at suitable points, as indicated by the numeral 15, to secure light-ness o'f construction.

The lug 1 0 passes through the web of the compression member 6 preferably so as to protrude therethrolrgh sufficiently to al low of its terminal face being provided with the vertical recess 1'6, within which is adapted to lie the shank of the suitable bolt 17 carried by the tugs 14 of the brake shoe head, which are so disposed as to lie above and below the boss or lug 1b when the head has been slipped into position on the end 'of the beam. This arrangement enables the brake shoe head to be removably mounted on the "end of the beam, it being apparent that with the removal of the bolt i6 the head may be readily :longitndihal ly shifted into and out of position on the united ends of the compression and tension members.

It will be apparent that by my improved manner of connecting the tension and compression members the severe operative strains thrown upon the beam will not be converted into leverage strains tending to cause a backward flexing of the beam, but

that the stresses will be transmitted in a straight line from the center of the head along the tension member to the point of support of the latter at the base of the strut, and that the equal distribution of forces, due to the pull of the beam at the center of the brake heads, operates to maintain full braking efliciency.

Other advantages of my invention, such as the simplicity of the direct connection in the particular construction shown between the tension and compression members without the intervention of thrust or other filler blocks, which more or less serve to set up lost motion at the joint, will be appreciated by those skilled in the art. The connection shown also dispenses with such means of connection between the tension and compression members and between the brake head and beam as reduce the cross-sectional strength of these members at points requirgreat strength, as in the case of rivets and bolts passing directly through the several members.

It will be apparent that changes may be made in the construction shown without "departing from my invention and I do not therefore desire to limit myself thereto. For instance, it will be apparent that compression and tension members of various cross-sectional shapes may be employed, as stated above, instead of the channel and strap shapes respectively, and that the principle of strengthening the beam, as disclosed in the specification, may find a ditierent embodiment from that shown in the drawings.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a trussed beam construction, the combination of a compression member, a strut, and a tension member in engagement with the end oi the compression member, and a lug carried by the tension member and entering a recess in the compression memher; the tension member passing downwardly directly from the lug obliquely in a straight line to the base of the strut.

2. In a trussed beam construction, the combination of a compression member, a strut, a brake shoe head, a tension member having a lug in interlocking engagement with the end of the compression member, the

tension member passing downwardly su b-' brake shoe head to the base of the strut in a straight line.

4. In a trussed beam construction, the combination of a compression member, a strut, a brake shoe head, and a tension member having a terminal head provided with a lug adapted to enter an opening in the end of the compression member, the tension member passing downwardly from a point substantially central of the brake head to the base of the strut in a straight line.

5. In a trussed beam construction, the combination of a compression member, a strut, a brake shoe head, and a tension member having a lug projecting through an opening in the wall of the compression member.

6. In a trussed beam construction, the combination of a compression member, a strut, a brake shoe head, and a tension member having a face in parallel abutment with and a lug projecting through an opening in the wall of the compressiort member.

7-. In a trussed beam construction, the combination of a compression member, a strut, a brake shoe head, and a tension member having a face in parallel abutment with and a lug engaging an opening in the wall of the compression member, the tension member passing downwardly from a point substantially central of the brake shoe head to the base of the strut in a straight line.

8. In a trussed beam construction, the combination of a compression member, a strut, a brake shoe head, a tension member having a lug engaging an opening in the wall of the compression member, and means engaging with the lug of the tension member for securing the brake shoe head to the beam.

9. In a trussed beam construction, the combination of a compression member, a strut, a tension member having a lug engag ing an opening in the wall of the compression member, and a brake shoe head having a lug lying adjacent the lug-of the tension member, and constituting means for attachment of the head to the beam.

10. In a trussed beam construction, the combination of a compression member, a strut, a tension member having a lug engaging an opening in the wall of the compres sion member, and a brake shoe head having a plurality of lugs lying about the lug of the tension member.

11. In a trussed beam construction, the combination of a compression member, a strut, a tension member provided with a lug adapted to interlockingly engage with the end of the compression member, a brake shoe head having lugs lying about the lug of the tension member, and means engaging with the lugs of the tension member and brake shoe head for securing the head in place.

12. In a trussed beam construction, the combination of a compression member, a strut, a tension member provided with a lug adapted to interlockingly engage with the end of the compression member, a brake shoe head having lugs lying about the lug of the tension member, and means engaging with the lugs of both members for securing the head in place; the tension member passing downwardly substantially from the center of the head obliquely in a straight line to the base of the strut.

13. In a trussed beam construction, the combination of a compression member, a strut, a tension member provided with a lug adapted to interlockingly engage with and project beyond the rear longitudinal face of the compression member, and a brake shoe head provided with fastening means adapted to engage with the protruding lug of the tension member. I

14. In a trussed beam construction, the combination of a compression member, a

strut, a tension member having a lug adapted to interlockingly engage a recess in the wall of the compression member, a brake shoe head having lugs lying on opposite sides of the lug of the tension member, and means carried by the lugs of the brake shoe head and engaging with the lug of the tension member.

15. In a trussed beam construction, the combination of a flanged compression member, a strut, a tension member provided with a lug adapted to interlockingly engage with and projecting beyond the rear longitudinal face of the compression member, and a brake shoe head embracing the respective ends of the compression and tension members, and provided with fastening means adapted to engage with-the protruding lug of the tension member.

16. In a trussed beam construction, the combination of a flanged compression member, a strut, a tension member having a lug adapted to interlockingly engage with a recess in the wall of the compression mem her, a brake-shoe head having lugs lying above and below the lug of the tension member, and means carried by the lugs of the brake-shoe head and engaging wit-h the lug of the tension member.

In testimony whereof, I have hereunto set my hand.

JOHN J. HOFFMAN. lVitnesses:

M. ARTHUR KELLER, M. A. BART.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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