US2872121A - Recessed tie plate - Google Patents

Description

Feb. 3, 1959 "r. G. THONGER 2,872,121

RECESSED TIE PLATE Filed March 7 1956 INVENTOR RECESSED TIE PLATE Thurland G. Thonger, Glen Cove, N. Y., assignor to Poor & Company, Chicago, 111., a corporation of Delaware Application March 7, 1956, Serial No; 570,080

1 Claim. (Cl. 238-306) This invention relates to an improvement in tie plates intended to effect a considerable reduction of the maximum stress in the lower web of the rail, more particularly in the lower outer fillet.

As is well known, the vertical load from car wheels is transmitted to a railway rail from the head to the base through the web while the lateral loading forces are imposed on the gauge side of the rail by the wheel flanges. Because of the height of the head of th rail above the base and the tie plate, this combination of vertical and lateral forces develop an outward force eccentric to the rail base which tends to concentrate stresses of considerable magnitude in the lower outer rail fillets; that is, the fillets at the field side of the rail. This tendency of the rail head to rock outwardly under the loading forces referred to tends to impose bending forces on the whole outer or field side of the flange of the rail base. These forces are manifested as a cantilever beam about a vertical line some what inside the lower outer fillet, thus producing a high compressive stress in both the lower outer fillet and the outer edge of the related flange of the base.

Accordingly, it is an object of the present invention to reduce the high stresses referred to by decreasing the eccentricity of load. To that end, it is proposed to provide an easement at the field side of the rail base and tie plate assembly, said easement being formed either as a recess at the field side of the bearing face of the tie plate or as a bevel at the underside of the rail.

In either case, the lateral width of the easement is definitely related to the inner face of the outer shoulder of the tie plate and the vertical center line of the rail so that there is no danger of the loading forces resulting in side thrust tending to overturn the rail.

A further object is to provide an easement which may be readily formed when the tie plates or rails are rolled, thereby involving no extra cost in production while providing practical and safety advantages of considerable value.

With the above and other advantages which will appear as the description proceeds, the invention consists in the combination and arrangement of parts hereinafter more fully described and claimed.

In the drawings:

Fig. 1 is a diagrammatic vertical sectional view of present practice illustrating a rail and tie plate combination with an exaggerated showing of the rail in dotted lines to indicate the result of forces tending to concentrate stress in the lower outer fillet, and which tend to downwardly how the rail base.

Fig. 2 is a diagrammatic vertical sectional view of a rail and tie plate according to the present invention, the rail again being shown in dotted lines, but the base line is bowed to a much lesser degree due to the contact point between the field side of the rail base with the tie plate being moved inwardly from the shoulder.

Fig. 3 is a view similar to Figs. 1 and 2 but showing the easement formed at the underside of one edge of the rail base.

2,72,l2l Patented Feb. 3, 1959 Similar references indicate like parts in the several views.

Referring to Fig. l, the tie plate 1 is provided with the field-side flange 2 and shoulder 3 and the shorter gaugeside flange 4 and shoulder 5, the space between the shoulders defining a fiat rail seat 6 011 which the bottom face 7 of the rail base 8 including flanges 9 and 10 rests.

The rail R also has the head 11 connected to base 8 by web 12 including the usual head and base fillets the outer one of which latter is designated as 13. The rail R has the center line or vertical axis A-B and from where B intersects the bottom face 7 of the rail to the outer edge of flange 9 adjacent shoulder 3 defines the length of a cantilever arm whose length equals x and upon which is imposed the entire effect of lateral thrust T applied by the wheel flanges to the gauge side of the rail head 11. As shown by dotted lines, the rail base 8 tends to bow or bend when all of the vertical and horizontal forces are concentrated in the region of the outer lower fillet 13. Such concentration leads to metal fatigue, cracks, or other weaknesses in the rail.

As shown by Fig. 2, the stress concentrations may be materially reduced by decreasing the length of the cantilever arm x. For example, in this embodiment, the tie plate 1 has its rail seating face 6 provided at the field-side shoulder 3 with an easement in the form of a recess 14 whose inner edge 15 is located inwardly of the outer edge of the flange 9 and therefore provides a cantilever army which is shorter than arm x. This recess extends the length of the tie plate.

As will be seen from Fig. 2, the bottom face 7 of the rail base 8 beyond the inner edge 15 of recess does not become bent or bowed and the remainder of the base is not bowed to as great a degree as shown in Fig. 1. This is because the lack of restraint of the edge of the rail base, due to vacated area of recess 14, relieves the base from excessive stresses.

Another modification to attain the same ends is illustrated in Fig. 3 where it will be seen that the upper face 6 of the tie plate is planar throughout its width, but the edge of the undersideof the rail is longitudinally beveled as indicated at 16 to provide the easement 1718. Here again the length of the cantilever arm y' is shortened as compared with the arm x of Fig. l, and undesirable stresses are relieved. It will, of course, be understood that the bevel 16 may be provided at both sides of the base flanges of the rail during the rolling of the rail at the mill.

The width of the recess 14 or the bevel 16 is critical in the respect that neither can be so wide as to provide a rail overturning hazard and yet they must be wide enough to keep the cantilever arm y or y as short as possible. In terms of measurement the width of the recess or bevel would be approximately to l" to allow a margin of safety against overturning of approximately 2:1 for most rails based on a 40,000# vertical and 10,000# lateral load.

Considering all of the factors involved, the preferred width of the recess or bevel is an optimum of 30% of the distance x Fig. 1, namely, one-half of the width of the rail base. However, due to inevitable rolling tolerances on both the plate and the rail, the dimensional range to take care of all conditions would be plus or minus 5% of the aforesaid 30% so that the dimension would lie within the critical range of 25% to 35% of one half of the width of the rail base.

From the foregoing it will now be seen that by providing the easement described, less stress concentration and a wider margin of safety, may be provided at the zone of the outer base fillets of a rail.

I claim:

A rail stress relieving tie plate, comprising, in combination, a planar surface for supporting the base of the rail, shoulders at each side of said surface comprising vertical wall portions of substantially the height of the edges of the base flanges of the rail and perpendicular to said surface to receive a rail therebetween by movemerit parallel to the vertical axis of the rail, and a depressed easement extending along the inside face of a related shoulder, said easement being of greatest depth adjacent said shoulder on the field side of the plate and inclining upwardly toward the vertical center of the rail and terminating between said related shoulder and the center of said planar surface whereby, the base flange on the side opposite the gauge side of the rail overlying said easement permits the bending forces imposed by the wheel flange thrust on the gauge side of the rail to be reduced substantially.

References Cited in the file of this patent UNITED STATES PATENTS 755,326 Steinberger Mar. 22, 1904 857,781 Abbott June 25, 1907 873,707 Bell Dec. 17, 1907 1,408,319 Ware Feb. 28, 1922 1,817,849 Schupp Aug. 4, 1931

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