US2081901A - Car retarder for railroads - Google Patents

Description

June 1, 1937. N c! BROWN 2,081,901

CAR RETARDER FOR RAILROADS Original Filed April 15, 1931 INVENTOR Ned C.L.Brown, BY

H15 ATTORNEY.

Patented June I 1937 PATENT OFFICE CAR RETARDER FOR RAILROADS Ned G. L. Brown, Scottsville, N. Y., assignor to General Railway Signal Company, Rochester,

Original application April 13, 1931, Serial No.

529,650. Divided and this application December 5, 1933, Serial N0.

3 Claims.

This invention relates in general to car retarders of the track brake type, and has more .particular reference to improvements in such retarder-s.

In the operation of car retarders it is desirable to safeguard against cars climbing up and out from between the retarder shoes and onto the top of the retarder shoes so as to possibly become derailed.

It is furthermore desirable in retarders to arrange the parts so that the retardation, with a given setting, will be substantially uniform under varying operating conditions.

With the above and other objects in view, it is ,:proposed, in accordance with the invention, to

provide various arrangements of car retarder parts to satisfactorily accomplish the above detailed desirable objects.

Further objects, purposes and characteristic features of the present invention will appear as the description progresses, reference being made to the accompanying drawing, showing, solely by way of example, and in no manner in a limiting sense, several forms of the present invention. In the drawing:- I

This application is a division of my pending application Serial No. 529,650 filed April 13, 1931 for Car retarders for railroads.

Fig. 1 is a sectional view of a fragment of a car retarder, showing one form of the invention.

30 Fig. 2 is a side elevation (on line 2-2 of Fig. 2)

viewed in the direction of the arrows.

Fig. 3 is a sectional view of a portion of a car retarder in accordance with a modified form of the invention.

Fig. 4 is a sectional View of a portion of a car retarder in accordance with another modified form of the invention.

Fig. 5 is a sectional view of a portion of a car retarder in accordance with another modified form of the invention.

Referring now to the drawing, and first to Fig. 1, there is here shown track rail l, and a car wheel 2, in connection with two retarder shoes 3 and 1, carried by shoe beams SB, centered by spring means S, and positioned by rocker arms A, the retarder shoe 3 being an outside shoe, and

4 an inside shoe.

For the purpose of illustrating the present in- 50 vention, only a fragmentary portion of the retarder, as shown in the drawing, appears necessary. The retarder shoes can be connected up and operated in any desired or usual manner, as,

for example, the manner shown in the patent of W. K. Howe, No. 1,852,572, April 5, 1932.

In Fig. 1, the retarder shoe 3, which normally bears on the outer face of the car wheel, is made of the same material as the shoe 4, which normally bears against the inner face of the car wheel, and this material may be cast or rolled steel, or any other usual or desired material. Due to the sharp edges on the outer face of the car wheel, and to the general configuration of railway car wheels, the outer face is much rougher where it contacts with a retarder shoe, than is the inner face. As a result, the outer shoe exerts a much greater retarding force on the wheel, than does the inner shoe, and when made of the same material as the other shoe, such outer shoe is subjected to a faster rate of wear than is the inner shoe.

As shown in Fig. 1, due to the greater rate of wear on the outer shoe, the upper edge of the shoe, as indicated, becomes beaded up and over to form an upward projection 3 on the same. Due to this beaded over portion, when a car wheel, for any reason tends to climb out from between the retarder shoes and does climb out, so as to bear with its tread on the upper face of the outer retarder shoe, the wheel is raised higher than it would be, were there no head 3 Under these conditions the inner shoe has its upper edge, which is not materially headed over because of the relatively less wear on the inner shoe, bearing against the flange of the wheel at a relatively low point on the flange, whereby the force acting between the inner shoe 4 and the car wheel, in a direction at right angles to the curved surface of the wheel at the point of contact between the wheel and shoe 4, and designated as 5, can be resolved into a vertical component 6, and a horizontal component 1, the vertical component 6 being of considerable magnitude. From this it can be seen that there'is a considerable tendency for the car wheel 2 to be forced upward, by this component 6, until the wheel flange rides on the inner brake shoe, under which conditions the car can easily become derailed. The condition just explained, and shown in Fig. 1, is of course an abnormal condition, and does not occur during normal operation of the retarder.

. In Fig. 1, the brake shoes are fastened to the shoe beams SB by bolts b received in bolt holes 8 in the brake shoes and brake beams, in the same manner as shown in Patent No. 1,852,572, above referred to. In order that the brake shoes may not tilt inwardly toward'the rail, when a car wheel has climbed up from between the brake shoes and is riding thereon, and in order to holdthe shoe more firmly in place on the beam it is desirable to have the bolt for the bolt hole 8 positioned as high up as possible on the brake shoe. As shown in Fig. 1, this bolt hole is shown positioned with the head receiving portion 8 which is narrow and elongated in a direction parallel with the lower face of the brake shoe head, and formed as by milling, or the like, flush with the lower face 8 of the braking portion of the retarder shoe. Due to this narrow elongated head of the bolt, which has a width not substantially greater than the diameter of the shank of the bolt, it is possible to position the bolt higher up on the shoe than would be possible with a bolt having a conventional square head. It is desirable to use bolts passing freely through the brake shoe, as shown, rather than to use bolts which pass through the brake beam and screw into tapped holes in the shoe. In the case of bolts passing freely through the shoe, the bolts can adjust themselves under strain so as to all act in concert, and thus successfully carry the load, while in the case of bolts that are threaded into tapped holes in the brake beam and brake shoe, no such adjustment is possible, with the result that first one and then another of these bolts may shear off under the strains imposed thereon. At the point of the brake shoes where they are bolted to the brake beams, the brake shoe is upwardly grooved, as at 9, to a considerable distance above the upper edge of the head receiving portion 8 Due to wear on the brake shoes, there is a tendency to mushroom the braking face of the shoe so as to form a downwardly projecting bead at the lower edge thereof, such as to prevent the easy withdrawal of the connecting bolts which fasten the shoes to the brake beams, unless provision is made therefor by the groove 9. With the groove 9, formed as shown, see Fig. 2, the edge e of this groove can be mushroomed over a considerable amount without interfering with the ready withdrawal of the connecting bolts. This is preferably the case with both inner and outer shoes.

Referring now to Fig. 3, a slightly modified form of the invention is shown, wherein the same rail i and car wheel 2 is shown. The outer brake shoe Ill, and the inner brake shoe I I, however, while of the same form as shown in Fig. 1, is differently comprised.

The outer brake shoe ID, in this form, is made of considerably harder material than is the inner brake shoe I I, whereby, not only to decrease the co-efficient of friction between it and the car wheel, but to decrease the amount of wear per unit of retardation, whereby, under normal conditions, no bead is formed at the upper edge of the shoe it as is the case in the Fig. 1 form. In this improved form, accordingly, if the wheel 2 climbs out, as illustrated, so as to ride with its tread on the upper face of retarder shoe ID, the wheel is still positioned low enough down to per- Init the upper inner edge of shoe II to bear high up on the curve of the flange. In these circumstances the force acting between the shoe II and the wheel 2, and designated as I2, can be resolved into a horizontal component I3, and a vertical component I4. It is seen that the vertical component I4, is here of a magnitude to be practically negligible, and hence to have practically no effect toward raising the wheel higher so as to move it entirely out from'between the brake shoes and cause a derailment. By slightly raising the shoes I and II, the component I4 can be reduced to Zero.

Thus, in the form of Fig. 3, the difference in hardness between the inner and outer shoes, has obviated the tendency for a car wheel to climb entirely out from between the brake shoes. In the form of Fig. 3, if excessive wear should cause a bead to be raised on the upper inner edge of brake shoe I-S, the relatively softer inner shoe I I would be worn to have at least an equal bead thereon so that the point of application of the force I2 would be as high up on the wheel, as illustrated, and hence would avoid any tendency towards derailment.

In the form of invention shown in Fig. 3, the channels 9 in the two shoes are provided, as in the first form, for facilitating ready removal of the connecting bolts, even though the faces of the brake shoes be beaded over by wear.

Referring now to Fig. 4, there is here shown a modified form of the invention wherein the outer shoe I5, and the inner shoe It, is formed of the same material and of the same hardness, with the outer shoe E5 of the form shown in Fig.1.

The inner shoe- It, however, is formed with a vertical braking face and a downwardly and outwardly sloping upper face Ii, as shown, and this inner shoe is positioned higher up on the wheel, sothat the upper edge of the shoe It is considerably higher than the upper edge of the shoe I5. This is possible, in railway practice, due to the fact that the clearances at the inner sides of the wheels of rolling stock, are slightly greater than on the outer sides.

Due to a faster rate of wear on the outer shoe I5, the upper edge becomes beaded over, as at I5 so that the car wheel 2 on climbing out from between the rails, rides on its tread on the bead I5 to raise the wheel higher than would be the case if there were no bead I5 This additional raising of the wheel 2, however, causes no tendency for the wheel to be forced higher, as in Fig. l for example, since the brake shoe It is positioned so as to bear against the inner face of the car wheel at a considerably higher point than the curved portion of the wheel flange, and hence the force represented as at 53, between the inner shoe I5 and the car Wheel, has no vertical component whatsoever, and hence has no tendency to raise the car wheel further.

In addition to the advantage in Fig. 4 of preventing atendency towards derailment by positioning the inner shoe-higher than theouter shoe, there is an added advantage. It is well recognized that the higher up the brake shoe is positioned on a car wheel, the greater is the relative motion between the brake shoe and the car wheel and hence the greater is the retardation due to a given pressure. By positioning the brake shoe I6 higher up than shoe I5, such shoe is exerts a greater retardation than would otherwise be the case. Since however the outer shoe, with an arrangement as shown in Fig. l and Fig. 3 exerts perhaps two-thirds of the total retardation, the increase in retardation of the inner shoe I6 due to its higher position, is merely a step in the right direction. Due to the fact that the car wheel is subject to being covered with grease and oil and the like on its outer face,-while it is relatively immune to such action on the inner face,

the retarding force exerted by the outer brake shoes vary widely under different operative conditions and hence when the larger part of the total retardation is produced by the outer shoes, this variation due to surface-conditions of the outer face of the two wheels is rather troublesome. It is thus seen that the added retardation of the inner shoes I 6, due to their higher position, is a step in the direction of making the total retardation more constant regardless of wheel condition and the like.

A further advantage of the invention, as shown in Fig. 4, is that the inner shoe l6 due to its higher position, provides a clearance space l9 between the socket 8 for receiving the attaching bolt heads, and the lower edge 20 of shoe l6, so that it is unnecessary with the inner shoes of the form of Fig. 4, to form a groove to permit ready withdrawal of the connecting bolts. Furthermore since with the form of Fig. 4 there is no tendency for the car wheel to ride up on top of the retarder shoe 16, there is no need for the connecting bolts for this shoe Hi to be positioned higher up than as shown in Fig. 4.

Thus the form of shoe shown in Fig. 4, for the inner shoe I6 is advantageous from several points of View.

Referring now to Fig. 5, the outer shoe 2| is of the same form as all of the other outer shoes, thus far described, but is made of harder material than the inner shoe 22, in much the same manner as shoe [0, of Fig. 3, is made of harder material than the inner shoe l l, of such Fig. 3.

Due to the shoe 2| being of harder material than in Fig. 4, the co-efiicient of friction between it and the outer face of the wheel 2 is less than in'the form of Fig. 4, and hence little or no bead is formed thereon. The main advantage of the form of Fig. 5, over that of Fig. 4 is, however, that the harder shoe 2| exerts less retardation than does the softer shoe [5 of the earlier form. Thus the tendency for the outer shoe to exert the larger portion of the total retardation, due to the rougher contact surfaces between the outer face and edge of the car wheel and the outer retarder shoe, is more than offset by the fact that the inner shoe 22 is of softer material and is positioned higher up on the car wheel. These effects can be sufiiciently exaggerated to cause the inner shoes to produce the larger portion of the total retardation, whereby a variation in the amount of retardation produced by the outer shoes, due to difference in the amount of oil and grease and the like on the outer face of the car wheels, can cause but a very small percentage difference in the total retardation. In this manner the form shown in Fig. 5 results in a relatively uniform degree of retardation under varying conditions of car wheels as met in actual practice, and is thus a very considerable advantage.

In the forms of inner shoes shown in Figs. 4 and 5, the downwardly sloping upper faces l1, causes any bead formed on the upper edge thereof, to roll back and down and prevents such bead from projecting upwardly enough to interfere with proper clearances.

The grooves 9 are formed in the outer shoes 15 and 2| of Figs. 4 and 5 respectively, for the same purpose as described above, namely, to permit ready withdrawal of the connecting bolts which fasten the shoes to their carrying brake beams.

The above described forms of invention are given merely by way of example and the relative degrees of hardness of the brake shoes, and the relative elevations of the inner and outer brake shoes can, of course, be varied at will to produce greater or lesser effects of the characters described above.

It is also apparent that the above rather specific description of several forms of this invention has been given solely by way of illustration, and is not intended, in any manner whatsoever, in a limiting sense. Obviously, this invention can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications, are intended to be included by this invention, as come within the scope of the appended claims.

Having described my invention, I now claim:-

1. In a retarder, in combination, a shoe beam at each side of a track rail, a brake shoe carried by each shoe beam, the shoes being composed of material of equal hardness, the inner shoe being supported by its shoe beam at a greater elevation above the rail than that of the outer shoe, whereby to prevent derailment and cause the inner shoe to contribute a larger proportion of the combined retardation caused by the inner and outer shoes, said inner shoe having an upper face sloping downwardly and away from the rail to thereby prevent any bead worn at the upper edge of the braking face of the inner shoe from projecting upwardly above clearance limits.

2. In a retarder, in combination, a shoe beam at each side of a track rail, a brake shoe carried by each shoe beam, the inner shoe being supported by its shoe beam, at a greater elevation above the rail than that of the outer shoe, whereby to prevent derailments and cause the inner shoe to contribute a larger porportion of the retardation caused by the inner and outer shoes, said inner shoe having an upper face sloping downwardly and away from the rail to thereby prevent any bead worn at the upper edge of the braking face of the inner shoe from projecting upward above clearance limits, the outer shoe being formed of harder material than the inner shoe to thus cause the inner shoe to contribute a greater share of the total retardation produced by the two shoes.

3. In a retarder, in combination, a shoe beam at each side of a track rail, a brake shoe carried by each shoe beam, the inner shoe being supported by its shoe beam at a greater elevation above the rail than that of the outer shoe, whereby to prevent derailment and cause the inner shoe to contribute a larger proportion of the combined retardation caused by the inner and outer shoes, said inner shoe having an upper face sloping downwardly and away from the rail to thereby prevent any bead worn at the upper edge of the braking face of the inner shoe from projecting upwardly above clearance limits.

NED C. L. BROWN.

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