US1942802A

US1942802A - Car retarder for railroads

Info

Publication number: US1942802A
Application number: US529650A
Authority: US
Inventors: Ned C L Brown
Original assignee: General Railway Signal Co
Current assignee: SPX Corp
Priority date: 1931-04-13
Filing date: 1931-04-13
Publication date: 1934-01-09
Anticipated expiration: 1951-01-09

Description

Jan. 9, 1934. N. c. L. BROWN 1,942,802

CAR RETARDER FOR RAILROADS Filed April 15, 193.1

PIC-21.1. 2

ATTOR N EY Patented Jan. 9, 1934 PATENT OFFICE 1,942,802 CAR RETABDER roa RAILROADS Ned C. L. Brown, 'Scottsville, N. Y., assignor to General Railway Signal Company, Rochester,

Application April is, 1931. Serial No. 529,650

11 Claims.

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

This application is a continuation in part of my application Ser. No. 464,892 filed June 30, 1930 for Car retarders for railroads.

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 as to facilitate replacement of def ctive and worn out parts, such, particu larly, as the retarder shoes.

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:-

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

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 1, and a car wheel 2, in connection with two retarder shoes 3 and 4:, 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 sary. The retarder shoes can be connected up and operated in any desired or usual manner, as, for example, the manner shown in the application of Ned C. L. Brown, Ser. No. 464,892 filed June 30,

In Fig. l, 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 wheehfor any reason tends to climb out from between the retardedshoes 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 bead 3 Under these conditions the inner shoe has its upper edge, which is not materially beaded 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 '7, 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 I; received in bolt holes 8 in the brake shoes and brake beams, in the same manner as shown in application 464,892, 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 hold the 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 H 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 9 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 1 and car wheel 2 is shown. The outer brake shoe 10, and the inner brake shoe 11, however, while of the same form as shown in Fig. 1, is difi'erently comprised.

The outer brake shoe 10, in this form, is made of considerably harder material than is the inner brake shoe 11, 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 10, 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 10, the wheel is still positioned low enough down to permit the upper inner edge of shoe 11 to bear high up on the curve of the flange. In these circumstances the force acting between the shoe 11 and the wheel 2, and designated as 12, can be resolved into a horizontal component 13, and a vertical component 14. It is seen that the vertical component 14, 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 10 and 11, the component 14 can be reduced to zero.

Thus, in the form of Fig. 3, the difierence 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 10, the relatively softer inner shoe 11 would be worn to have at least an equal bead thereon so that the point of application of the force 12 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 headed over by wear.

Referring now to Fig. 4, there is here shown a modified form of the invention wherein the outer shoe 15, and the inner shoe 16, are formed of the same material and of the same hardness, with the outer shoe 15 of the form shown in Fig. 1.

The inner shoe 16, however, is formed with a vertical braking face and a downwardly and outwardly sloping upper face 1'7, as shown, and this inner shoe is positioned higher up on the wheel, so that the upper edge of the shoe 16 is considerably higher than the upper edge of the shoe 15. 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 15, the upper edge becomes beaded over, as at 15 so that the car wheel 2 on climbing out from between the rails, rides on its tread on the bead 15 to raise the wheel higher than would be the case if there were no bead 15 This additional raising of the wheel 2, however, causes no tendency for the wheel to be forced higher, as in Fig. 1 for example, since the brake shoe 16 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 18, between the inner shoe 16 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 a tendency towards derailment by positioning the inner shoe higher than the outer 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 16 higher up than shoe 15, such shoe 16 exerts a greater retardation than would otherwise be the case. Since however the outer retarder 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 16 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 16, 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 16 due to its higher position, provides a clearance space 19 between the socket 8 for receiving the attaching bolt heads, and the lower edge 20 of shoe 16, 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 16 to be positioned higher up than as shown in Fig. 4.

Thus the form of shoe shown in Fig. 4, for the inner shoe 16 is advantageous from several points of view.

Referring now to Fig. 5, the outer shoe 21 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 10, of Fig. 3, is made of harder material than the inner shoe 11, of such Fig. 3.

Due to the shoe 21 being of harder material than in Fig. 4, the co-eflicient 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 21 exerts less retardation than does the softer shoe 15 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 sufficiently 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 face 17, 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 21 of Figs. 4 and 5 respectively, for thesame 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 suchforms 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 car retarder, a brake beam, a brake shoe having a shank and a horizontal braking portion projecting from the shank, an attaching bolt fastening the shank to the brake beam at a point flush with the lower face of the braking portion, and a channelled out portion in the lower face of the braking portion at the point of connection by the bolt to facilitate removal of the bolt.

2. In a car retarder, a brake beam, a brake shoehaving a shank and a horizontal braking portion projecting from the shank, an attaching bolt fastening the shank to the brake beam at a point flush with the lower face-of the braking portion, and a channelled out portion in the lower face of the braking portion at the point of connection by the bolt to facilitate removal of the bolt, said channel having a lower face spaced from the bolt head.

3. In a brake shoe for car retarders wherein the shoe is carried by a brake beam, in combination, a brake shoe having a shank and a horizontal braking portion projecting from the shank, an attaching bolt for fastening the shank to a brake beam at a point flush with the lower face of the braking portion, and a channelled out portion in the lower face of the braking portion at the point of connection by the bolt to facilitate removal of the bolt.

4. In a brake shoe for car retarders wherein the shoe is carried by a brake beam, in combination, a brake shoe having a shank and a horizontal braking portion projecting from the shank, an attaching bolt for fastening the shank to a brake beam at a point flush with the lower face of the braking portion, and a channelled out portion in the lower face of the braking portion at the point of connection by the bolt to facilitate removal of the bolt, said channel having a lower face spaced from the bolt head.

5. A brake shoe for car retarders of the track brake type, comprising, a braking portion and a portion for detachably connecting the shoe to a carrying means, and means on the braking portion for preventing changes in the braking portion due to braking from interfering with detaching the shoe.

6. A brake shoe for car retarders of the track brake type, comprising, a braking portion and a portion for detachably connecting the shoe to a carrying means, and a cut-out portion on the braking portion for preventing beading over of the edge of the braking portion due to braking from interfering with detaching the shoe.

7. In combination, a brake shoe for car retarders of the track brake type, and attaching means for detachably connecting the shoe to a brake beam, the shoe having a retarding portion, and an attaching portion, and means for preventing changes in the shoe due to braking operations from interfering with detaching the shoe from the beam.

8. In combination, a brake shoe for car retarders of the track brake type, and an attaching bolt for detachably connecting the shoe to a brake beam, the shoe having a retarding portion, and an attaching portion, and cut-out means in the shoe for preventing heading over of portions of the shoe due to braking operations from interfering with withdrawing the bolt for detaching the shoe from the beam.

9. In a car retarder of the track brake type, in combination with a brake beam and a brake shoe having a shank and a horizontal braking portion projecting from the shank, means for detachably connecting the brake shoe to the brake beam comprising a narrow elongated rectangular slot in the said shank and substantially parallel with and in line with, the lower face of the projecting braking portion, and a bolt having a narrow elongated rectangular head fitting into the slot, and a stem passing through the brake shoe and brake beam, and means for fastening the parts in place.

10. In a car retarder, in combination, a brake beam, a brake shoe having an extending shank and a brake head projecting at substantially right angles thereto, and carried by the brake beam, a bolt having a shank passing through the shank of the brake shoe at a point substantially in line with the lower face of the brake head, and through the brake beam, means for fastening the bolt in place to hold the shoe in engagement with the brake beam, the bolt having a narrow elongated rectangular head, and a slot in the shank of the brake shoe having parallel side faces, for matching the bolt head.

11. In a car retarder, in combination, a brake beam, a brake shoe having an extending shank and a brake head projecting at substantially right angles thereto, and carried by the brake beam, a bolt having a shank passing through the shank of the brake shoe at a point substantially in line with the lower face of the brake head, and through the brake beam, means for fastening the bolt in place tohold the shoe in engagement with the brake beam, the bolt having a narrow elongated rectangular head with an arcuate rear face, and a slot in the shank of the brake shoe having parallel side faces, and an arcuate inner face for matching the bolt head.

NED C. L. BROWN.