US2499812A - Car retarder - Google Patents

Description

, March 7, 1950 G. c. BELTMAN CAR RETARDER Filed Dec. 8 1945 Sehens-sheet 1 N /NVE/vTo/Q I GE'OPGE' c. BELT/WAN Q 5%, v jf-a6 Y March 7 1950 G. c. yBl-:LTMAN 2,499,812

' CAR RETARDER Filed DeG. 8, 1945 5 SheetsSheet /M/ENTOR GEO/Q65 C. BELT/WAN March 7, 1950 G. c. BELTMAN 2,499,812

CAR RETARDER Filed Dec. 8. 1945 5 sheets-sheet 4 /N VEN TOR GEORGE C. BELT/WAN BY/w,

March 7, 1950 G. c. BELTMAN 2,499,812

CAR RETARDER Filed Dec. 8, .1945 5 Sheets-Sheet 5 /NVENTOR G50/Q65 C'. en-MAN Patented Mar. 7, 1950 CAR RETARDER George C. Beltman, Chicago, Ill., assigner to Caine Steel Company, Chicago, Ill., a corporation of Illinois Application December 8, 1945, Serial No. 633.690

(Cl. 18S-62) 22 Claims.

My invention relates to the operation and construction of railroad classification yards and includes among its objects and advantages a reduction in personnel and particularly personnel required to perform acts involving risk of physical injury; together with a reduction in the amount and cost of equipment.

In the accompanying drawings:

Figure 1 is a diagram of part of a classication yard especially constructed for the purpose of the invention;

Figure 2 is a diagram indicating the levels and slopes of the tracks of the diagram of Figure 1;

Figure 3 is an enlarged diagram of a portion of Figure 1;

Figure 4 is a plan view of a car retarder.

Figure 5 is a vertical section on line 5-5 of Figure 4, indicating the details of construction of one of the pressure linkages.

Figure 6 is an end elevation as on the line 6--6 of Figure 4;

Figure '7 is a somewhat enlarged side elevation of one of the individual friction elements of Figure 4;

Figure 8 is an enlarged detail as in section on line 8 8 of Figure 7;

Figure 9 is an enlarged detail as on line 9-8 of Figure 7;

Figure 10 is a plan view of the pivot arm of Figure 8;

Figure 11 is a detail section as on line II-II of Figure 7; j

Figure 12 is a section similar to Figure 11, indicating the condition obtaining when the wheel is abreast of one of the springs.

Referring first to Figures 1, 2 and 3, the hump I8 delivers cars to the accelerating incline I2 from which they pass along a ladder track I4 also inclined downward a little to its end point I8. Switches along the ladder track distribute the cars to storage tracks I6, from Whichassembled trains can be withdrawn on outlet ladder tracks 3|. inclination, but are at different elevations corresponding to the slopeof the ladder vtrack I4, as indicated at IIia in Figure 2. y

At the inlet end of each storagev track I have indicated retarder units 22, 24, 28 and 32. The

The tracks I6 all have the samel units 22 and 24 may be adjusted together from t an operating station at 20. Similarly, the units 28 and 32 may be adjusted from stations at 26 and 30.

adjustment.

The absorbing unit The absorbing units 22, 24, 28 and 32 may all be identical except as toloa'd capacity. As illustrated in Figures 4A to l2, inclusive, each unit' comprises four duplicate friction shoes 34 ar- All the retarders maybe of the same identical type illustrated in Figure 4, but those.

46 of an outer rocker 48 lying outside the rail 36. It also has a similar socket to receive the pivot 58 of the rocker 52 positioned inside the rail. As best indicated in Figure 7 each shoe 34 is securely bolted to the T-shaped face plate 54 of each of its associated rockers. The outer rocker 48 is apertured at 56 to receive the tension bolt 58 and the walls of the aperture are notched as best indicated at 60 in Figure 5 to provide a horizontal fulcrum for the inner pressure cup 62, which receives the thrust of the spring 64 acting in compression between the cup 62 and the outer pressure disc 66. The bolt 58 passes through a suitable aperture in the web of the rail 36, which aperture is larger than the bolt to leave a clearance. The rocker 52 has an aperture 68 to receive the bolt and a pressure plate I8 spaced from the rocker proper, which is also apertured. The bolt terminates in a head 'I2 guided between arms 'I3 on the rocker 52 (see Fig. 10), and vertically bored for pivotal connection with the bell-crank lever 14. The short arms of the bell-crank levers 14 are twin cams 'I6 which ride on the pressure plates 'I0 and force the heads 'I2 of the bolts axially in the direction to compress the springs 64. The long arms extend inwardly from opposite sides as clearly indicated in Figure 4 to connect with flexible tension members 18. v

Suitable means are provided for actuating all the bell-cranks 14 in unison to build up the pressure of the springs 64. I have illustrated a draw bar extending throughout the length of the retarder and suitably guided as by contact with a pair of supporting angles 82. The draw bar 88 carries aseries of rigid cross pieces 84, one for each pair of opposite pressure mechanisms.'

Suitable means are provided for operating the draw bar 80. I have indicated a brake setting mechanism 86 of any suitable or well-known type operated by the hand wheel 88 through reduction gearing to take up on the chain 90, and

provided with a control lever 92 for disconnecting the parts t0 relieve the tension quickly. From the chain 88 the vflexible cable 94 may extend downward around a sheave 96, across past r the center of the track and around a second sheave 98, and finally around a third sheave |80 pivoted on a vertical axis, to connect at |02 with simple adjusting nut on the outer end oi' the bolt 58. In one successful device all the springs except the first one at the entering end of the retarder are adjusted to give a maximum compression of 8,000 pounds, corresponding to substantially 6,000 pounds at the working face of the shoe 34. The first set of springs at the entering end is adjusted for maximumloads of about half or two-thirds as much as the remaining springs for a purpose that will be explained hereinafter.

When there are no car Wheels between the shoes 34 the parts might be relatively loose and move into undesired positions especially by falling over against the rail 3G. I .have indicated light positioning springs |08 encircling the bolt 58 on either side of the rail web and pushing against the shoes to hold them out in gentle contact with the cups 62 and cams 16. These springs have a strength that is negligible compared with the main springs 64. In one success-- ful installation with the main spring 64 carrying a maximum load of 8,000 pounds, the springs |06 will collapse into contact between the coils under a load of about 160 pounds and the force they exert in the position of Figure may be about half as great.

Referring now more particularly to Figures 7, 11 and 12, it will be noted that each shoe 34 operates as a unitary structure with its seven rockers. Each 36 inch span between the rockers. which also are pressure points for the springs 64, carries the load of the springs in Iflexure whenever a wheel is in a position such as that indicated at |08 in Figures 7 and 11. Thus, if the flexibility of the shoe is properly computed, the parts may be so designed that the conditions of operation Figures 11 and 12 will obtain. In Figure 11 the wheel |08 is in the same position asl in Figure 7, midway between pressure points indicated by arrows in Figure 11, and the shoe 34 is curved as indicated (with material exaggeration in Figure 11 so that the operation is apparent). The shoes on both sides bear at the .edges of the wheel |08 at the four points identified bv the reference character ||0 and the flexibility of the shoes 34.causes them to curve out between the bearing points as indicated by the reference character ||2 in Figure 1l. It will be apparent that this concentrates the effective friction load at the points where.

the almost vertical movement of the wheel por tions engaging the shoe is a maximum, and that even if therev is no actual observable clearance at the point ||2 the effective frictional pressure per unit area will be either zero or substantially negligible.

In Figure 12 I have illustrated the wheel |08 directly in line with one of the pressure mechanisms but it will be apparent thatthe leverage of the other pressure mechanisms 36 inches away in either direction will push the shoes 34 together as indicated at both ends of Figure 12,-

so that again the friction load will be concentrated at the points ||0. Even ii' the spring opposite the points ||2 in Figure 12 maintains some slight contact between the shoes and the wheel, it is possible to design the shoes of such a degree of flexibility that the effective load at the points ||2 will still be a very minor friction of that at the points ||0. Thus. throughout the travel of each individual wheel through the entire retarder. the retarder will do nearly all its rubbing at the points where it has the most effective grip for the purpose of absorbing mum energy from the wheel.. l

Tests in actual operation have evidenced that the device does operate as in Figures ll-and 12 and have also indicated a retarding effect which, compared with the load on the springsv I4, is of the order or magnitude of twice as great as the retarding effect that can be obtained with the same load and shoes that are rigid and do not flex, such as the shoes of U. S. Patent 1,757,428, issued May 6, 1930 to W. K. Howe. For the loading of 6,000 pounds per pressure point and 36 inches between pressure points, a proper ratio between flexibility and strength can be obtained with such a cross section as is indicated in Figures 8 and 9 where the upper thick portion of the shoe measures 2*/2 inches high by 13/4 inches thick, and the lower flange is 21/2 inches high by 5/3 inches thick. Such a cross section gives the desired flexibility and has suillcient strength to carry the spring pressure with an ample margin of safety.

It is also of greater rigidity and strength in the vertical plane than in the horizontal plane and strong enough to carry the full weight of a car which may happen to jump up into a position where the wheels ride, not on the rails 36 but with their treads rolling on top of the outer shoes 34 and their iianges 4 still in eiective side engagement with the inner shoes 34 so that such a car is still guided in alignment with the rails and will drop back onto the rails after it has rolled over the retarder. Upon reference to Figure 9 it will be noted that the inner shoe 34 is positioned about a half inch higher than the outer shoe Whereas the flange |4 projects about an inch lower than the tread IIS. This is a desirable safety factor because, in casual hand operation. it does happen occasionally that a light, empty car comes along rather fast and the operator sets the retarder too tight and the car does actually hop up and ride along the top of the retarder instead of going through it as it should. However, the likelihood of such an occurrence is materia-ily reduced by having the rst set of springs adjusted for lower tension than the remaining sets. Thus by the time-the full load of the second set of springs is biting on the advancing wheels and tending to lift them, there is at least a half or 173 load making the shoes bite on the rear and rising portion of the wheel and tending to hold it down. Thus the tendency to jump may befsubstantially halved, and if the wheel once gets as far as the wheel |08 in Figure 7, A

there is no longer any effective tendency to rise.

It is noted that, as clearly indicated in Figure 7, the wheels are far enough apart so that they do not interfere with each other in permitting the flexible grip illustrated in Figures 11 and 12. The wheel H8 in Figure 7 is indicated in substantially the position of the other wheel of a truck 'including the wheels |08 and ||8, and by the time the wheel |08 is in register with the next rocker, the wheel I8 will also be in register with the second rocker beyond, so that the diagrams of Figures 11 and 12 apply with equal validity to both wheels at all times.

Without further elaboration the foregoing will sc fully explain my invention that others may readily adapt the same for use under various conditions of service. It will, for instance. be obvious that operation without retardation from point I0 in Figure 1 clear through to the retarders on the individual tracks I6 may be practiced with any type of retarding mechanism. Also that the control for the retarders on the individual tracks may be the manual control of an experienced operator based on his judgment; or that automatic g control means sensitive to both the weight and speed of the approaching cars may be placed at positions 20, 26 and 30. Such control means may, for instance, be according to United States Patent 1,626,920 issued May 3, 1927, to J. P. Coleman, or any of various other automatic control mechanismsalready known to the art. The use of such control mechanisms at the points designated is included in the present invention.

I claim:

1.- Car retarding equipment of the type comprising, pairs of opposing shoes adjacent each rail along a predetermined length of track; the shoes of each pairbeing guided in movement toward and away from each other to grip'and rub on a wheel on the rail between them; and a plurality of spring means, each acting independently, at a plurality of uniformly spaced points along said shoes; in which said shoe is constructed and arranged to have a strength and rigidity in a vertical plane much greater than that in the plane of spring thrust, and suflicient to carry the weight of the wheel of a loaded car; said shoe being sufficiently flexible in the plane of spring thrust'to cause the pressure against the wheel to be concentrated at two spaced points at the edges of the wheel and substantially eliminated at points intermediate between said points of concentration; the first spring means at the inlet end of said equipment being adjusted to exert forces materially less than those exerted by the rest of the spring means; said shoes and spring means for each rail being in transverse alignment abreast of those for the other rail.

2. Car retarding equipment of the type comprising, pairs of opposing shoes adjacent each rail along a predetermined length of track; the shoes of each pair' being guided in movement toward and away from each other to grip and rub'on a wheel on the rail between them; and a plurality of spring means, each acting independently, at a plurality of uniformly spaced points along said shoes: in which said shoe is a single continuous member having a strength and rigidity in a vertical plane much greater than that in the plane oi spring thrust, and suiiicient to carry the weight of the wheel of a loaded car; said r shoe being suiiiciently iiexible in the plane of spring thrust to cause the pressure against the wheel to be concentrated at two spaced points atthe edges of the wheel and substantially eliminated at points intermediate between said points of concentration.

3. Car retarding equipment of the type comprising, a pair of opposing shoes adjacent a rail along a predetermined length of track; said shoes being guided in movement toward and away from each other to grip and rub on a wheel on the rail between them; and a plurality of spring meanaeach acting independently, at a plurality of uniformly spaced points along said shoes: in which each said shoe is a single continuous member sufliciently flexible in the plane i the wheel to be concentrated at two spaced points at the edges of the wheel and substantially elimirail between them; and a plurality ot spring means, each acting independently, at a plurality ofspaced points along said shoes: in which each of said shoes is sufficiently flexible in the plane of spring thrust to cause the pressure against the wheel to be concentrated at two spaced points at the edges of the wheel and substantially eliminated at points intermediate between said points of concentration; the longitudinal distance between said spring means being greater than the distance between said points of concentration and not more than two thirds of the distance between the wheel axles of a railroad car truck.

5. Car retarding equipment of the type comprising, pairs of opposing shoes adjacent each rail along a predetermined length of track; the shoes of each pair being guided in movement toward and away from each other to grip and rub on a wheel on the rail between them; and a plurality of spring means, each acting independently, at a plurality of spaced points along said shoes: in which said shoe is suiiicien-tly flexible in the plane of spring thrust to cause the pressure against the wheel to be concentrated at two spaced points at the edges of the wheel and substantially eliminated at points intermediate be tween said points of concentration. 1

6. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track: a plurality of pressure units uniformly spaced along one of said rails; each unit comprising an upwardly opening housing set into said road bed andextending across under said rail; a pair of rockers supported in and extending above said housing on opposite sides of said rail; said rockers terminating at their lower ends 'in trunnions having horizontal axes; said housing having open sockets positioned to receive said trunnions in freely removable relationship:

nated at points intermediate between said points along a predetermined length of track; said shoes being guided in movement toward and away from each other to grip and rub on a wheel on the each rocker having a face plate at its upper end; said face plates extending above the level of said rail: a tension boltz said rockers being apertured to receive said bolt: said bolt passing through said apertures andextending beyond the same at both ends; an abutment on one end of said bolt facing toward the adjacent rocker: a compression spring acting between said abutment and rocker: take up means connected to the other end of said bolt and engaging the other rocker for moving said other rocker away from said other bolt end: said take up means comprising: a bent lever of the first class having pivotal connection at its elbow with said bolt end: one arm of said lever having a cam face positioned to engage and move said rocker awav from said bolt end: means for adjusting the eiective length of said bolt hy moving said abutment longitudinally of said bolt; an inner ilegible shoe extending longitudinallv along the inner side of said rail and past all said pressure units and connected to the upper ends of all the rockers inside said rail; an outer flexible shoe extending longitudinally along the outer side of said rail. and past all said pressure units and connected to the upper ends of all the rockers outside said rail: both said shoes extending above the level of said rail; said outer shoe extending to a lower level than said inner shoe: said springs being positioned outside said rail and said levers being positioned inside said rail: a second set of pressure units and shoes along the other rail; the pressure units of. the second set being in transverse alignment abreast of the rst set: the levers of the second set being positioned inside said other rail: means in the nature of a single central drawbar extending longi- 7 tudinally past the ends of all said levers for actuating all the levers of both sets of pressure units simultaneously, to precondition said equipment so that the entry of one ormore car wheels between said shoes will separate said shoes and compress said springs to a predetermined degree; and anti-rattle springs encircling at least some of said bolts for each pair of shoes and pressing against said rockers to hold said shoes at least partly open and in position to receive an entering wheel.

7. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track: a plurality of pressure units uniformly spaced along one of said rails; each unit comprising an upwardly opening housing set into said road bed and extending across under said rail; a pair of rockers supported in and extending above said housing on opposite sides f said rail; said rockers terminating attheir lower ends in trunnions having horizontal axes; said housing having open lsockets positioned to receive said trunnions in freely removable relationship; each rocker having a face plate at its upper end; said face plates extending above the level of said rail; a tension bolt; said rockers being apertured to receive said bolt; said bolt passing through said apertures and extending beyond the same at both ends; an abutment on one end of said bolt facing toward the adjacent rocker; a compression spring acting between said abutment and rocker; take up means connected to the other end of said bolt and engaging the other rocker for moving said other rocker away from said other bolt end; said take up means comprising: a'lever having pivotal connection with said bolt end; one arm of said lever having a cam face positioned to engage and move said rocker away from said bolt end; means for adjusting the effective length of said bolt by moving said abutment longitudinally of said bolt; an inner exible shoe extending longitudinally along the inner side of said rail and past all said pressure units and connected to the upper ends of all the rockers inside said rail; an outer iiexible shoe extending longitudinally along the outer side of said rail and past all said pressure units and connected to the upper ends of all the rockers outside said rail; both said shoes extending above the level of said rail; said outer shoev extending to a lower level than said inner shoe; said springs being positioned outside said rail and said levers being positioned inside said rail; a second set of pressure units and shoes along the other rail; the pressure units of the second set being in transverse alignment abreast of the first set, the levers of the second set being positioned inside said other rail; and means in the nature of a single central drawbar extending longitudinally past the ends of all said levers; for actuating all the levers of both sets of pressure units simultaneously to precondition said equipment so that the entry of one or more car wheels between said shoes will separate said shoes and compress said springs to a predetermined degree.

8. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track: a plurality of pressure units uniformly spaced along one of said rails; each unit comprising a support extending across under said rail; a pair of rockers supported by and extending above said support on opposite sides of said rail; said rockers being movable on said support about horizontal axes passing near their lower ends; each rocker at its upper end extending above the level of said rail; a tension bolt; said rockers being apertured to receive said bolt; said bolt passing through said apertures and extending beyond the same at both ends; an abutment on one end of said bolt facing toward the adjacent rocker; a compression spring acting between said abutment and rocker; take up means connected to the other end of said bolt and engaging the other rocker for moving said other rocker away from said other bolt end; said take up means comprising: a cam positioned to engage and move said rocker away from said bolt end; means for adjusting the effective length of said bolt by moving said abutment longitudinally of said bolt; an inner iiexible shoe extending longitudinally along the inner side of said rail and past all said pressure units and connected to the upper ends of all the rockers inside said rail; an outer iiexible shoe extending longitudinally along the outer side of said rail and past all said pressure units and connected to the upper ends of all therockers outside said rail; both said shoes extending above the level of said rail; said outer shoe extending to a lower level than said inner shoe; said springs Ibeing positioned outside said rail and said levers being positioned inside said rail; a second set of pressure units and shoes along the other rail; the pressure units of the second set being in transverse alignment abreast of the first set, the levers of the second set being positioned inside said other rail; and means in'cluding a single central drawbar extending longitudinally past said pressure unita for actuating all the cams of both sets of pressure units simultaneously.

9. .Car retarding equipment comprising,y in combination with the rails and road bed of a railroad track; a plurality of pressure units spaced along one of said rails; each unit comprising a support; a pair of rockers pivotally supported by and extending above said support on opposite sides of said rail; a tension bolt; said rockers being apertured to receive said bolt; said bolt passing through said apertures and extending beyond the same at both ends; an abutment on one end ,of said bolt facing toward the end of the adjacent rocker; a compression spring acting between said abutment and rocker; take up means connected to the other end of said bolt and engaging the other rocker for moving said other rocker away from said other bolt end; said take up means comprising: a cam positioned to engage and move said rocker away from said bolt end; means for adjusting the effective length of said bolt; friction shoes along the inner and outer sides of said rail supported by said rockers; and means extending past said pressure units for actuating all the cams of said pressure units simultaneously; said cam being shaped for uniform continuousl displacement throughout its range of movement.

10. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track; a plurality of pressure units spaced along one of said rails; each unit comprising a pair of rockers on opposite sides of said rail; said rockers being pivoted about horizontal axes below the level of said rail; a transverse tension connector adjacent said rockers and eX- tending laterally beyond the same at both ends; an abutment on one end of said connector facing toward the adjacent rocker; a compression spring acting between said abutment and rocker; and takeup means connected to the other end of said connector and engaging the other rocker for moving said other rocker away from said other connector end; said takeup means comprising a cam positioned to engage and move said rocker away from said connector end; brake shoes carried by said rockers; and means for actuating said cams; said cams being shaped for substantially uniform continuous displacement throughout their range of movement.

11. A shoe for car retarders having an upper tread section of horizontal dimension less than the width of the rail head and vertical dimension greater than its horizontal dimension; and a downwardly extending web integral with said tread portion and of vertical dimension substantially the same as said tread portion and horizontal dimension not greater than half said tread portion; and pressure means for applying localized pressure at spaced points along said shoe, saidpoints being spaced apart by more than the diameter of a railroad wheel; said shoe being supported at said pressure points only and devoid of any stiiening reinforcement against iiexure under load; said shoe being sufciently flexible in the horizontal plane to cause the pressure against the wheel to be concentrated at two spaced points at the edges of the wheel and substantially eliminated at points intermediate between said points of' concentration.

12. A shoe for car retarders having an upper tread section of horizontal dimension less than the width of the rail head and vertical dimension greater than its horizontal dimension; and a downwardly extending web integral with said tread portion and of vertical dimension substantially the same as said tread portion and horizontalv dimension not greater than half said tread portion; and pressure means for applying localized pressure at spaced points along said shoe, said points being spaced apart by more than the diameter of a railroad wheel; the maximum horizontal dimension of said head being not more than two inches; and the distance between successive pressure points being not less than thirty inches; said shoe being suiiiciently flexible in the horizontal plane to cause the pressure against the wheel to be concentrated at two spaced points at the edges of the wheel and substantially eliminated at points intermediate between said points of concentration.

13. A combination according to claim 11 in which said means for applying localized pressure is constructed and arranged to permit the shoe, at the point where pressure is applied, to rotate by its own distortion about a vertical axis into diierent angular positions, whereby the flexing action proceeds with each wheel along the length of the shoe without abrupt discontinuities of action.

14. A combination according to claim 13 in which said means for applying localized pressure comprises a series of downwardly extending levers; each lever having its upper end fastened to said shoe; each lever having a pintle at its lower end; a xed open socket for each lever into which said pintle may be dropped; whereby said shoe and lever assembly as a whole floats on said pintles without other guiding support; each le- I .combination with the rails and road bed, of a railrod track; a plurality of pressure units uniformly spaced along one of said rails; each unit comprising an upwardly opening housing set into said road bed and extending across under said t one of said rockers between said abutment and said rail; a compression spring acting between said abutment and rocker; takeup means connected to the other end of said tension connector and engaging the other rocker for moving said other rocker away from said takeup means; said takeup means comprising: a bent lever of the rst class having a pivot connection at its elbow with Said connector; one arm of said lever having a cam face positioned to engage and move said rocker away from said pivot; means for adjusting the effective length of said connector by moving said abutment; an inner exible shoe extending longitudinally along the inner side of said rail and past all said pressure units and connected to the upper ends of all the rockers inside said rail; an outer exible shoe extending longitudinally along the outer side of said rail, and past all said pressure units and connected to the upper ends of all the rockers insidesaid rail; an outer exible shoe extending longitudinally along the outer side of said rail, and past all said pressureunits and connected to the upper ends of all the rockers outside said rail; both said shoes extending above the level of said rail; said outer shoe extending to a lower level than said inner shoe; said springs being positioned outside said rail and said levers being positioned inside said rail; a second set of pressure units and shoes along the other rail; the pressure units of the second set being in transverse alignment abreast of the rst set; the levers of the second set being positioned insidesaid other rail; means in the nature of a single central drawbar extending longitudinally past the ends of all said levers for actuating all the levers of both sets of pressure units simultaneously, to precondition said equipment so that the entry of one or more car wheels between said shoes will separate said shoes and compress said springs to a predetermined degree; and relatively light springs operatively connected to hold said shoes at least partly open and in position to receive an entering wheel.

16. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track: a plurality of pressure units uniformly spaced along one of said rails; each unit comprising an upwardly opening housing set into said road bed and extending across under said rail; a pair of rockers supported in and extending above said housing on opposite sides of said rail; said rockers terminating at their lower ends in trunnions having horizontal axes; said housing having open sockets positioned to receive said trunnions in freely. removable relationship; each rocker having a face plate at its upper end; said face plates extending above the level of said rail; a tension connector also extending on opposite sides of said rails; an abutment on said connector near one end thereof facing toward said rail with one of said rockers between said abutment and said rail; a compression spring acting between said abutment and rocker; takeup means conextending longitudinally along the inner. side of said rail and past. all the rockers inside said rail; an outer flexible shoe extending longitudinally along the outer side of said rail, and past all said pressure units and connected to the upper ends of all the rockers. outside said rail; both said shoes extending above the level of said rail; said outer shoe extending to a lower level than said inner shoe; said springs being positioned outside said rail and said levers being positioned inside said rail; a second set of pressure units and shoes along the other rail; the pressure units of the second set being in transverse alignment abreast 'of the rst set; the levers of thesecond setbeing positioned inside said other rail; means in the nature of a single central drawbar extending longitudinally past the ends of all said levers for actuating all the levers of both sets of pressure units simultaneously, to precondition said equipment so that the entry of one or more car wheels between said shoes will separate said shoes and compress lsaid springs to a predetermined degree.

17. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track: a lplurality of pressure units uniformly spaced along one of said rails; each unit comprising an upwardly opening housing set into said road bed and extending across under said rail; a pair of rockers supported in and extending above said housing on opposite sides of said rail; said rockers terminating at their lower ends in trunnions having horizontal axes; said housing having open sockets positioned to receive said trunnions in freely removable relationship; each rocker having a face plate at its upper end; said face plates extending above the level of said rail; a tens1on connector also extending on opposite sides of said rail; an abutment on said connector near one end thereof facing toward said rail with one of said rockers between said abutment and said rail; a compression spring acting between said abutment and rocker; takeup means connected to the other end of said tension connector and engaging the other rocker for moving said other rocker away from said takeup means; said takeup means comprising: a bent lever of the l first class having a pivot connection at its elbow with said connector; one arm of said lever having a cam face positioned to engage and move said rocker away from said pivot means for adjusting the effective length of said connectorby moving said abutment; an inner exible shoe extending longitudinally along the inner side of said rail and past all said pressure units and connected to the upper ends of all the rockers inside said rail; an outer ilexible shoe extending longitudinally along the outer side of said rail, and past all said pressure units and connected to the upper ends of all the rockers outside said rail; both said shoes extending above the level of said rail; said outer shoe extending to a lower level than said inner shoe; said springs being posisitioned outside said rail and said levers being the pressure units of the second set being in transverse alignment abreast of the iirst set; the levers of the second set being positioned inside said other rail; and means in the nature of a single central drawbar extending longitudinally past the ends of all said levers for actuating all the levers of both sets of pressure units simultaneously.

18. Car retarding equipment comprising, in combination with the rails and road bed of a railroad track: a plurality of pressure units spaced along one of said rails; each unit comprising a pair of rockers on opposite sides of said rail; said rockers being pivoted about horizontal axes below the level of said rail; a transverse tension connector adjacent said rockers and extending laterally beyond the same at both ends; an abutment on one end of said connector facing toward the adjacent rocker; a compression spring acting between said abutment and rocker; and takeup means connected to the other end of said connector and engaging the other rocker for moving said other rocker away from said other conon small concentrated areas at the edges of a standard car wheel without load bearing contact elsewhere, in spite of the usual surface irregularities in such wheels.

20. A shoe according to claim 19 having strength under vertical load sufcient to carry the weight of the wheel of a freight car over a 36-inch span.

21. A shoe according to claim 19 in which the shoe is not less than twice as strong and not less than five times as stiff under vertical bending load as under horizontal bending load.

22. A shoe according to claim 19 having an upper portion of greater thickness than its lower portion, said upper portion protruding to present Ha rubbing surface to a car wheel.

GEORGE C. BELTMAN.

-REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,157,622 Frank Oct. 19, 1915 1,576,623 Barr Mar. 16, 1926 1,612,865 Hannauer et al Jan. 4, 1927 1,899,899 Morgan Feb. 28, 1933 1,906,359 Begley et al. May 2, 1933 2,045,695 Brown June 30, 1936 2,081,901 Brown June 1, 1937 2,129,301 Bone Sept..6, 1938. 2,139,324 Abeloos Dec. 6, 1938 2,190,073 Knudsen Feb. 13, 1940 2,263,244 McGowan Nov. 18, 1941 2,393,146 Clark 1/ Jan. 15, 1946 FOREIGN PATENTS Number Country Date 229,402 Great Britain Feb. 23, 1925

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