US2633210A - Car retarder - Google Patents

Description

March 31, 1953 G. c. BELTMAN ETAL 2,633,210

CAR RETARDER Filed March 18, 1947 3 Sheets-s l March 31,1953

CAR RETARDER Filed March 18, 194'! G. C. BELTMAN ET AL [I II I i l I I'lll'l 3 Sheets-Sheet 2 Ill/Ill March 31, 1953 G. c. BELTMAN ET AL CAR RETARDER 3 Sheets-Sheet 5 Filed March 18, 1947 Patented Mar. 31, 1953 CAR RETARDER George C. Bel'tman and Donald ,H. Sweet, Chicago, 111.; said Sweet assignor to saidBeltman.

Application MarchlS, 19432; SerialN 0.335315 I9'Claims; 1.

This. invention. relates. to the automatic controlof. the. speedof wheeled vehicles, and more specifically to. the automatic retardation of vehicles not. otherwise controlled as, to speed; It includes. among its objects andv advantages the automatic, reduction of the. speed of the wheeled vehicle toa predetermined minimum definitely greater. than. .zero, and. finds its chief field of usefulness in railroadclassification yards.

lInthe, accompanying drawings:

Figure, 1. is a side elevation of a retarder unit according to. the invention;

Figure 2 is a plan view of the same;

' Figure '3 is an end view of the retarder of Figure- 1. as on line 3-3 of Figure 2;

Figure 4 isa side elevation of the cross beam forming a double pivot for the beams of Figure l;

Figure.5 is an end. view of the same beam;

Figure 6 is a section through the dash pot of a retarder, on line 6-6 of Figure 7;

Figure 7'is a section on line 'll of Figure 6;

Figure 8 is. a partly diagrammatic side elevation of one means for blocking up the beams when desired; and

Figure 9 is a similar view of a modified actuating means.

In. the embodiment of' the" invention selected for illustration, each retarder unit is a pair of short rail sections inserted in both rails side by side. beam 40' and a short beam 42. As best indicated in Figures 1" and 2', the beams 49 and 42 are inserted between lengths of ordinary rail 44 and 4H and constitute a continuation of the rail" surface. over which. the. wheels of the car pass. Figure 1, the. contour of. the rail surface, hidden by the flanges of the beams, is indicatedv by the dot, and dash. line 45. In unloaded position the upper surfaces of the beams 46 and 42 occupy the upper dot and dash line position of Figure 1 and present a short incoming section about 12 inches. longsloping. upward about an inch. to a maximum elevation. at 48,.anda longer section about 54..inches long. The last six inches is level with. the fixed rail 45, and the remainder slopes up to join. the short section. The joints, between all. these sections are notched. as. best indicated. at 50 in. Figure 2, to transfer the wheel more smoothly from one section to the next.

The. long. beam. 45 hasa fixed pivot 52 spaced aboutv 6. inches from the fixed rail 46, and supporting, hangers 411' formed in the upper flanges etoflthe beam. At the other end, the fianges54 end. in. downwardlyopening hangers; or. hookshaped' end portions 56,v whichhoole-shaped por- Eachinsert section includes a long i time overlie: the loadbearing upper.- edge of. the carrier cross beam 53. The short beam 42' also has flanges. Bil extending throughout its. length and terminating, in similar hangers 6 I symmetrically spaced outside the hangers 55 and, riding on the same crossbeam 58. Adjacent the fixed rail 44:, the flanges 50 have downwardly facing hangers 5| riding on struts 62. on either side of the rail. 44, which struts rest, in. fixed. sockets 53. The flanges 54 and. both extend up about one and one-half inches above the rail. This saves weight and also guards: against wheels leaving the rail.

The articulate supportingmeans described permit the beams 40 and 42 to'move down to bring the rail surface to the position of the lower dot and dash lines of. Figure l, with the apex. 48 about two inchesbelow the level of the rails 44 and 45.

It will be apparent thata wheel moving off. the rail 44 and encountering the beams in. the. lower dot and dash position will be subjected to antaccelerating force as it rolls down the beam 42 and to an equal retarding action as it subsequently rolls up along beam 40 so that it will tend to return tothe rail 46 with they same speed as it had. when it left the rail 44. However, if a wheel encounters the beams in the upper position and. rides part or all the way out to the apex ia-while the beams remain substantially in that position, it will not be accelerated. And if the beams are then lowered substantially to the lower position, as by letting the cross beam.58, sink,.the sinking will not accelerate the wheel but the subsequent climb up thelong beam 45 will retard it.

The cushioning means for the cross beam 58 is both load sensitive and speed sensitive and is best illustratedin detail in Figures 3 to 7.. The beam 58 is centrally notched down at the top as at 64 (see Figure 4) to clear the rail portions of the beams 49. and 42. Under each wing it has a downwardly facing abutment surface 66, and projecting downwardly in the middle is a strut 68 entering a dash pot indicated as a whole by the reference character 10.

A pistcnlz moves vertically in the cylinder 13', kept filled with liquid up to. the level indicated at 14 in Figured, as by means of a conventional float valve H. It has a guiding skirt l5 sliding freely in the cylinder 13, and a plurality of grooves 18 for. collecting fluid working up around the, skirt, whichfluidfiows back to the outside through weep. holes'lfl, The top of the. piston has an upwardly-facing socket receiving-the end of the strut 68. The peripheral wall of the cup contains one or more threaded openings, each receiving a calibrating plug 82, which may be made up with central openings of various sizes. A lifting spring 84 is housed under the piston I2 and abuts the bottom of the dashpot. Air accumulating under the piston can exit through a weep hole 11. The tension of the lifting spring 84 exceeds the weight of the beams 40 and 42 by a proximately half of the load carried by one wheel of a. light or empty car, when the parts are in elevated position. When the piston is depressed to the bottom of its stroke, the spring load may desirably increase to about or A of the load of the wheel of a light car. Suitable means are provided for positively preventing the beams from rising above the full line position of Figure 1, such as bolts 36 anchored in the foundation and engaging the upper surface of the bottom flange 88 of the beam 49. A rin 89, held down by bolts 9|, facilitates assembly by carrying the initial tension of the spring 84, when the strut 68 is not effective for that purpose. Check valves 85 operate to let the piston move up with relatively negligible damping action.

It will be apparent that a car wheel rolling along at 12 miles per hour will travel the length of the short beam 42 in approximately of a second and then spend more than & of a second passing over the long beam 40, if it does not slow down. But the same wheel rolling along at 2 miles per hour will take six times as long on both beams, spending /3 of a second on the short beam 42 and about a, of a second on the long beam 40. And to depress the beams to their lowermost position in an 18th of a second will force the liquid in the dash pot to pass through the plug 82 six times as fast as when the displacement takes place in of a second. Accordingly, the resistance of the dash pot to the fast downward movement will be greater than that oifered to the slow movement in the ratio of about 36 to 1.

Thus the plug may be calibrated to oppose the fast movement with sufficient force to momentarily carry the load of the wheel to the end of the short beam 42 while only a small fraction of the complete downward displacement has occurred, and the rest of the displacement will take place while the wheel is passing over the initial portions of beam 40. Thus a very light car go-, ing 12 miles an hour might pass over the beam 42 while the fulcrum lowers a half inch and the fulcrum would go down another inch and a half as the wheel covered about the first foot of the beam 40. Such a wheel would never have any downhill travel, climbing a slight incline most of the way across the beam 42 and being let down about an additional inch on the beam 48 and required to climb back up again.

But at the same speed a car of maximum weight might push the pivot down an inch and a half by the time it reached the end of the beam .42 and get down the full distance by the time it had covered about six inches of the beam 4% It will be apparent that, traveling at the same speeds, a heavy car will be required to do materially more climbing than a light car so that both will be retarded but the heavy car will be retarded more strongly.

However, when either a heavy car or a light car travels as slowly as two miles an hour across the beam 42, there is ample time for the beams to go to substantially their lowermost position before the wheel has covered more than a fraction of the length of the beam 40. And under such circumstances substantially the entire ef feet on the wheel will be to let it roll downhill and then uphill to the same vertical displacement without material retardation. And at all intermediate speeds throughout the range, the timing of the dash pot action will make it effective to exert a retarding action substantially proportional to the square of the speed of the car.

Cut-out controls After a train has been assembled, it is customary to go into the yard with a locomotive and bring the train out at the same end where it was put in. An ideal installation might be provided with trackage at the other end to take the trains out, but in any practical installation it will be necessary to bring the cars back out at the same end occasionally, and in present yards that is common practice. When a train is being taken out over the gravity retarders, it is undesirable to have either the locomotive or the cars operate the gravity retarders although, at reasonable speeds not exceeding 15 miles an hour, the main effect would be only to jounce the cars up and down a little.

Referring to Figures 1 and 8, the abutments 66 of the cross beam 58, when the parts are in elevated position, are spaced three inches from foundation abutments indicated in Figure l at 93, which abutments function as a stop to limit the downward movement. A blocking yoke is provided comprising end blocks 92 and a cross reach 94 curved back to allow clearance for the strut 68. The yoke is normally held in the position of Figure 1 by light tension springs 95. The blocks 92 are-two inches high, and may be drawn across under the abutment faces 66 so that downward movement of the beams is limited to a position where they present a level track. The parts may be drawn into blocking position by a pair of tension rods 96.

Means are provided for actuating the tension rods 96 in two different ways. An automatic actuating means is illustrated in Figure 8 and includes a plate 98 about 36" long, lying beside the wheel-carrying surface and extending on both sides of the pivot 52. The plate is held in the position of Figure 8 by a pair of compression springs I00, one at each end, encircling guiding bolts I02. The guiding bolts pass through stationary guide blocks I04 apertured to leave substantial clearance around the bolts to permit free movement of the plate. Washers I06 held in place by nuts I08 limit upward movement of the bolts I02. A bell crank lever HE] is pivoted at Hz and has one arm underlying the left hand bolt I02 and a vertical arm apertured to receive a tension rod I I4 loosely. Springs H6 and abutments I I8 on the rod I I4 provide a resilient lostmotion connection between the bell crank III! and the tension rod H4. The other end of the tension rod. connects with the upper end of a vertical catch lever I29 having a hook I22 movable to catch under the corner of a housing I24 on the right hand bolt I112. The pivot I26 for the catch-rod I20 is carried by a horizontal arm I21 on a shaft I28. The shaft I28 has a downwardly extending arm I30 receiving the tension rod 96 loosely. The tension rod has abutments I32 at its end and springs I34 between the abutment and the arm I30, which springs are two or three time as stiff as the springs pulling on the yoke 94 in the other direction.

1 Itaisxapparent thatpa wheel coming fromrthe left asviewedi inFigura 8 wiil first. depress the .lefinend; of the plate as... which will. fulcrum around-the rightzendabutment IM. This. down.- ward:movementiwillarocli.therbeil; cranlrlever II B' and? pull onthe. tension; member I:I 4: and-swin thecatchlevenoverunder thehousing I24... This conditionwill.continuewhile the wheelcontinues to. the. middle; of theP-plate; 9.8: and the: housin the. load (lithe; wheeL on: the beam and; .on the.

abutment-(faces. 66; so that byrtheatimather. wheel leaves the; plate. .93; the. blocks. 92: are.

ripped, byxtheweightzoff the; wheel; passing over;

and: remain. that; condition until. the wheel" leavespthebeamjz .lnrthev meantime, the parts have: returned. to. the initial position. so; that. as

$001.11 as: the spring: at; begins to. lift the beams backin the. yoke.- s4 and, blocks ezhcan move back to: the position of Figure 11 under: the: unopposed'forcaof' thespringsefi.

It; is also; apparent that alwheel'. traveling in the other direction,.. after it; has traversed both beams; either with or without being; retarded thereby, will: depressfirst' theisright' hand end of plate: 9.8! and then' the. left: hand. end. The. first depression: will move; theliousing I24 downheiow .the;.1hoolc I22. and. the second depression will merely" compress: one. of the springs. II'G a little and cause the toe of the hook I22 to press lightly againstathahousing I24. But: nothing willhappen. to": the. blocks 92, so that a following wheel bathe; same truck or another carcoupled to the carwhich hasjust passed :will find" the entire device. ready to. function and effect whatever re-- tardation the speed and load of" the'next wheel callsafor. I

Referring: to. Figure 8, I have indicated a stringer, or" pipe, I38, which maybe connected tozth'ezends of the dependinglevers I30 of a plurality cofzgravity retarders by means. of drag operating the blocks 92; The swinging control.

lever" hi2 normally occupies the; full line position oil ligure 9-, being held in contact withpivot-IM.

byrlightasprings: M'fi'strongenough: to carry the weightzof the lever and associated. parts-. The:

upper end of the lever projects about 2"" above the rail level, in. the plane: of the wheel flanges, and carries a contact roller I48 to engage the: wheel flanges. In-the fullline position, the fixed pivot I44 lies in: the. lower-apex of a. V-shaped' slot: Ifl'3 inthe lever I42. It willbe apparent that the initial contact of awheel coming from the left andengaging theroller |48wi1l tend to push the lever down until the pin I44 reaches the'end of the left arm of theV', after which further movement. will carry the roller I48 down to the right: andact through the springs I50 to pull on the tension member 96.

a However; a. wheel coming from the opposite direction: will tilt the lever I42 a counterclockdirection, which will either; do nothing to thetablocksaazi .orv-will push them a little further out; of 'blockingposition. With. the modification of Figure 9 it is necessary to connect the lever I42 through flexible tension. cords. I.52;so. that the automatic operation .is not'interferedwith by the. connection for manual operation.

Retarders of the conventional. side friction type are insensitive to both speed and load. Theycan do more retarding in a given distance than gravity retarders' according to the invention, but because the friction depends on the condition of" theside surfaces of the wheels, itis out of the question tosecure uniform or precise-results with them. However, a side friction retarder need only get the incoming cars down to anything between about live and about twelve-miles per hour, and gravityretarders can. finish the job witlrp-recisi'on.

A complete new installation: with gravity re-- tarders may advantageously employ: a hump-of materially reduced" height, and do all the re-- tarding by gravity. This. does away with many maintenance problems. In such an installation the: retard'ers on the-hump and in the switching section need to be set for much higher speeds.

Others may readily adapt the invention foruse under various conditions of service by employing one or more of the novel features disclosed, or equivalents thereof. For instance, in gravity retarders for high speed operation on the hump, it will be advantageous to increase thelength of the beam 42 by from 50% toand in any gravity retarderthat will be called on to move its plunger down. with more than half the acceleration of gravity, hangers on the cross beam should be connected to the cross beam, to follow it down without separation.

The preferred fluid for the. dash pot is primarily water, but. in climates where freezing temperatures are experienced, the. water should be protected by a. conventional anti-freeze com.- pound, preferably one with a higher. boiling point than waten such as diethylene glycol. When a yard is active, the energy absorbed by the dash pots will. keep the. contents boiling hot and evaporate substantial quantities of. water. But each heat increment will appear in the body of liquid at a point outside the cylinder Where the liquid jet issues from the cylinder, so that it will not be difficult to make the reservoir surrormding 1the cylinder of adequate area for. steam liberaion.

As at presentadvised, with respectto the. apparent scope of our invention, wedesire to claim thefollowing,subjectmatter:

1. In a railroad carretarder, incombinati'onx: spaced. fixed, rail sections positioned with. a. gap between them two longitudinally aligned'jbeams, together. bridging said gap; the one ofsaidjbe'ams at the end identified as. the, entrance. end being shorter than the other; a common pivotal sup.- port for the. adjacent ends ofsaid. beams; individual pivotal supports for the. remote ends. of said beams; said individual supports being positioned to hold the remote; ends of said. beams substantially level with the adjacent track said joint pivotal. connection being. vertically movable; hydraulic' dashpot mean connected. to said joint pivotal connection and adapted. toabsorb a;- maximum amount of. energy during downward movement and a relativelynegligible amount-of energy during upward movement; spring means biasing said joint pivotal connection upwardly; and stop means limiting the-action of'said spring meansto aposition: in which the parts are post-.

tioned for a full downward stroke of said dashpot.

2. In a railroad car retarder, in combination: spaced fixed rail sections positioned with a gap between them; two longitudinally aligned beams, together bridging said gap; a common pivotal support for the adjacent ends of said beams; means for guiding said joint pivotal connection in movement in a predetermined path between an upper position and a lower position; hydraulic dashpot means connected to said joint pivotal connection and adapted to absorb a maximum amount of energy during downward movement and a relatively negligible amount of energy during upward movement; spring means biasing said joint pivotal connection upwardly; and stop means limiting the action of said spring means to a position spaced from said lower position.

3. In a railroad car retarder, in combination: spaced fixed rail sections positioned with a gap between them; two longitudinally aligned beams, together bridging said gap; pivotal supporting means for the adjacent ends of said beamsysaid pivotal supporting means guiding said adjacent ends in movement in a predetermined path between an upper and a lower position; hydraulic dashpot means connected to said supporting means and adapted to absorb a relatively large amount of energy during downward movement and a relatively small amount of energy during upward movement; and means biasing said supporting means upwardly toward said upper position.

4. In an automatic railroad car retarder, in combination: spaced fixed rail sections positioned with a gap between them; a plurality of vertically movable sections articulated to each other and to said fixed rail sections to receive and support the entire weight of a car wheel to be retarded; hydraulic dash pot means underlying and connected to certain of said movable sections; said dash pot means having a permanently open vent and another vent provided with an inwardly opening check valve; and resilient means biasing said sections upwardly when not under load; said permanently open vent being small enough to cause said dash pot to temporarily support the entire weight of a car wheel moving at a speed in excess of three miles per hour.

5. In an automatic railroad card retarder, in combination: spaced fixed rail sections positioned with a gap between them; and a plurality of vertically movable sections articulated to each other and to said fixed rail sections to receive and support the entire weight of a car wheel to be retarded; hydraulic dash pot means connected to certain of said movable sections; said dash pot means having a permanently open vent and another vent provided with an inwardly opening check valve; and resilient means biasing said sections upwardly when not under load; said permanently open vent being small enough to cause said dash pot means to temporarily support the entire weightof a car wheel moving at a speed in excess of a predetermined maximum safe coasting speed at which a car can be stopped by impact with standing cars without injury to the contents of the car.

6. In an automatic railroad car retarder, in combination: a plurality of vertically movable rail sections articulated to each other and positioned to receive and support the entire weight of a car wheel to be retarded; hydraulic dash pot means connected to certain of said movable sections; said dash pot means having a vent; and resilient means biasing said sections upwardly when not under load; said vent being small enough to cause said dash pot to temporarily support the entire weight of a car wheel moving at a speed in excess of a predetermined maximum safe coasting speed at which the contents of the car will remain undamaged by stoppage of the car by impact with other cars standing still on the same track.

7. Equipment for automatically controlling the speed of a railroad car traveling on conventional rails, comprising, in combination with a fixed rail surface: a movable section interpolated in the rail surface; said section having an entrance end and an exit end; means for supporting the exit end of said section at all times substantially level with the continuation of said rail surface; the entering end of said section being vertically movable and normally at a predetermined level with respect to the adjacent fixed rail surface; means supporting said section in undisturbed position with a force materially less than the weight normally imposed on said section by a car wheel; stop means limiting the downward movement of the inlet end of said section to a predetermined maximum; and means for absorbing and dissipating energy in retarding the downward movement of said inlet end; said absorbing means being adapted to resist downward movement with a variable force approximately proportional to a higher power, not less than about the square, of the speed of the downward movement.

8. Equipment for automatically controlling the speed of a railroad car traveling on conventional rails, comprising, in combination with a fixed rail surface: a movable section interpolated in the rail surface; said section having an entrance end and an exit end; means for supporting the exit end of said section at all times substantially level with the continuation of said rail surface; the entering end of said section being vertically movable and normally at a predetermined level with respect to the adjacent fixed rail surface; means supporting said section in undisturbed position with a force materially less than the weight normally imposed on said section by a car wheel; stop means limiting the downward movement of the inlet end of said section to a predetermined maximum; and means for absorbing and dissipating energy in retarding the downward movement of said inlet end; said absorbing means being adapted to resist downward movement with a variable force approximately proportional to a higher power, not less than about the square, of the speed of the downward movement; said absorbing means comprising a hydraulic dashpot.

9. Equipment for automatically controlling the speed of a railroad car traveling on conventional rails, comprising, in combination with a fixed rail surface: a movable section interpolated in the rail surface; said section having an entrance end and an exit end; means for supporting the exit end of said section at all times substantially level with the continuation of said rail surface; the entering end of said section being vertically movable and normally at a predetermined level with respect to the adjacent fixed rail surface; means supporting said section in undisturbed position with a force materially less than the weight normally imposed on said section by a car wheel; stop means limiting the downward movement of the inlet end of said section to a J29 predetermined ;.maximum; and; means for' absorbing anddissipatingenergy in retardin the downwardmovement of said inlet end.

1.0,. Equipment for .automatically controlling the speed of a railroad car traveling on conventionalrails, comprising, incombination with a fixedzrailsurface; a movable section interpolated in the-rail surface; saidsecticn havingan zen- 'trance-zendirandaan exit end; means ior supporting the: exit end :of said section at all times substantially ,level with the continuation of said rail surface; the entering end of said section being vertically movable and V normally at a predetermined level with respect to the adjacent fixedmailsurface; means supporting said section in iundistmbe'd position with v a force materially less. athan :the :weight normally imposed on said section by aicar'wheel; stop means limiting the downward imovement of the (inlet end of said sectionirto a predeterminedzmaximum; andmeans for absorbingrand dissipating energyinretarding the downward movementiof .said'inlet end; said absorbing means being adapted :to resist downward- :movement with .a variable force approximately 'proportionallto aihigher power, not less thaniabout thesquare, .ofthe speed of the downward movement; said absorbing meanscomprising. ahydraulic-dashpot; the entering ,end of saidsection being normally materially above the fixedl -rail surface and vmovablefrom its uppervmostpositiondownwardly below said rail Surface.

1:11. z'Aitrack .retarder for railroad rolling stock comprising, in combination: a first track section,

identified as "a receiving section, supported at a substantiallyponstant level at one end, identified as the :receiving end; a second relatively long trackzsection adjacent saidfirst section and identified as a delivery section; said delivery section .havingqadelivery end remote from said receiving section supported at a substantially constant level; said receiving and delivery sections having their proximate ends insubstantial abutment; said proximate ends being articulated together about a common taxis; resilient :mean :normally supporting said "common axis in position :to .hold the :proximate :ends of said sections a 1predetermined idistance above a straight line joinin rthe remote ends-of said sections; stop means limiting upward'movement. of said axis 1 stop means limiting; .:.the downward :movement of said axis to a bottom positionspaced below astraightline ,j oining the ends cofgsaid. sections by a distance about twice as. great as. the upward deviation in the uppermost gposition of said axis; and damping means: for absorbing and dissipating ,energyin resisting downward displacement of said axis; said adamping means operatinghydraulically to oppose downward movement ofsaid axis with a force approximately proportional \to .a higher power, :not less than two, of the :speed of downward movement; said means for limiting downwardzdisplacement of said "axis including garfixed abutment and :a co-operative .cabutment movable downward with said axis; means for raising :the eflective level -:.of .said :fixed abutment .to ;limit downwardunovement of isai'd :axis :to azposition where said sections are in a "straight ,line, said raiisingrmeanscomprisinga:movable:block:adaptedjrto be interposed between said abutments when they are sufficiently separated; gmanual means formoving said raising'means into operative posi tie and :automatic means rendered ioperative byentryiof 2a 'wheel travelingrin reversezdirection, tormoving said raising"meansinto,operativexposition: \asaid -zautomaticxmean zincludingeatmovable element adjacent the delivery end of said-long section and :Positioned to bedisplaced in one sense bya wheelmoving-in-one directionrand in an opposite sense by a wheel moving .in the-ope posite direction; and a connection for actuating said raising means upon displacement of said movable element in one sense, but not by displacement in the. opposite sense.

12. A track retarder for railroad rollingstock comprising, .in combination: rat-first track section identified as a receiving section supp rted at a substantially,constantlevelat one end, identified as vthe receiving end; a second relatively long track section adjacent said first section andidentified as a delivery section; said delivery section having a delivery endremote from said receiving section supported at a substantially constant level; said receiving anddelivery sections having their proximate ends in substantial abutment; said proximate end being articulated together about a common axis; resilient means normally supporting saidcommon axis in position to hold the proximate ends 'of said sections a predetermined distance above a straight line joining'the remote ends of said sections; stop means limiting upward-movement of said axis; stop means limiting the downward movement of said axis to a bottom position spacedbelow ,a straight line aoining the ends of said sections by a distance about twice as great as the upward deviation {in the uppermost position of said axis; anddamping means resisting .downward displacement of said axis; said dampingmeans'for absorbing and d s ipatine en gy operating hydraulically to QPpOse downwardmovement of said axis, :with a force approximately proportional to a higher power, notless than tWQ,,10j thespeed .of down- Ward movement; said means-iorfimiting downward displacementofsaid axis including a fixed abutment and a .co-operati-veabutment movable downward'with said axis; means for raisin the efiective level of :said fixed abutment to limit downwardmovement of said axis to a position where said sections are in a straightline; and automatic means including a movable element adjacent the delivery end of saidlong sectionand positioned to bedisplaced in one sense ,bya wheel moving in one direction andin an-opposite sense by a wheel moving in the opposite direction a n,d a connection for actuating said raising means upon displacement of said movable elementdn one sense but motby displacement 11in 'thebpposite sense.

:A track retarder for wheeled vehicles comprising in combination: two adjacent trackzsece trons, having their proximate ends insubstantial abutmentand verticallymoyablerthe remotesends of said sections being supported at substantially constant :level; resilient means normally supportmg said -proximate ends ginua predetermined elevated position when not under load; stop :means positively limiting the downward :movement :of saidproximate endsyanddamping meansaiorabscribing-rand dissipating lenergyaduring downward displacement:ofsaidproximateendsgbutanotduring upward return tosaidmredetermined elevated position.

314. In an automatic railroad .Gar'retarder. in combination: a vertically movable rail section positioned to receive and support the entire weight :of ;a.- car wheel ztogbe retarded; hydraulic dashpot means -;eonne,c,ted :to said section; :said dashpot meanshaving 5a vent; and resilient means biasing said section upwardly when not under load; said vent being small enough cause said dashpot to temporarily support the entire weight of a car wheel moving at a speed in excess of a predetermined maximum safe coasting speed.

15. Equipment for automatically controlling the speed of a railroad car traveling on conventional rails, comprising, in combination with a fixed rail surface: a movable section interpolated in the rail surface; said section having an entrance end and an exit end; means for supporting the exit end of said section at all times substantially level with the continuation of said rail surface; the entering end of said section being Vertically movable and normally at a predetermined level with respect to the adjacent fixed rail surface; means supporting said section in undisturbed position with a force materially less than the weight normally imposed on said section by a car wheel; stop means limiting the downward movement of the inlet end of said section to a predetermined maximum; and means for absorbing and dissipating energy in retarding the downward movement of said inlet end; said absorbing means being adapted to resist downward movement with a variable force approximately proportional to a higher power, not less than about the square, of the speed of the downward movement; said absorbing means comprising a hydraulic dashpot; the entering end of said section being normally materially above the fixed rail surface and movable from its uppermost position downwardly below said rail surface; said movable section being combined with another movable section adjacent its entering end; said sections being articulated at their remote ends at the level of the adjacent fixed surfaces; said sections being articulated to each other at their proximate ends.

16. Equipment for automatically controlling the speed of a railroad car traveling on conventional rails, comprising, in combination with a fixed rail surface: a movable section interpolated in the rail surface; said section having an entrance end and an exit end; means for supporting the exit end of said section at all times substantially level with the continuation of said rail surface; the entering end of said section being vertically movable and normally at a predetermined level with respect to the adjacent fixed rail surface; means supporting said section in undisturbed position with a force materially less than the weight normally imposed on said section by a car wheel; stop means limiting the downward movement of the inlet end of said section to a predetermined maximum; and means for absorbing and dissipating energy in retarding the downward movement of said inlet end;

said absorbing means being adapted to resist downward movement with a variable force approximately proportional to a higher power, not less than about the square, of the speed of the downward movement; said absorbing means comprising a hydraulic dashpot; the entering end of said section being normally materially above the fixed rail surface and movable from its uppermost position downwardly below said rail surface; said movable section being combined with another movable section adjacent its entering end; said sections being articulated at their remote ends at the level of the adjacent fixed surfaces; said sections being articulated to each other at their proximate ends; said means for dissipating energy being a hydraulic dashpot connected to the proximate ends of said portions. 7

17. Equipment for automatically controlling the speed of a railroad car traveling on conventional rails, comprising, in combination with a fixed rail surface: a movable section interpolated in the rail surface; said section having an entrance end and an exit end; means for supporting the exit end of said section at all times substantially level with the continuation of said rail surface; the entering end of said section being vertically movable and normally at a predetermined level with respect to the adjacent fixed rail surface; means supporting said section in undisturbed position with a force materially less than the weight normally imposed on said secs tion by a car wheel; stop means limiting the downward movement of the inlet end of said section to a predetermined maximum; and means for absorbing and dissipating energy in retarding the downward movement of said inlet end; said absorbing means being adapted to resist downward movement with a variable force approximately proportional to a higher power, not less than about the square, of the speed of the downward movement; said absorbing means comprising a hydraulic dashpot; the entering end of said section being normally materially above the fixed rail surface and movable from its uppermost position downwardly below said rail surface; said movable section being combined with another movable section adjacent its entering end; said sections being articulated at their remote ends at the level of the adjacent fixed surfaces; said sections being articulated to each other at their proximate ends; said means for dissipating energy being a hydraulic dashpot connected to the proximate ends of said portions; the articulation of the exit end of said long portion being fixed; the other two articulations permitting slight longitudinal movement to compensate for the angularity of said portions.

18. A track retarder for wheeled vehicles comprising, in combination: two adjacent track sections having their proximate ends in substantial abutment and vertically movable; the remote ends of said sections being supported at substantially constant level; resilient means normally supporting said proximate ends in a predetermined elevated position when not under load; stop means positively limiting the downward movement of said proximate ends; damping means for absorbing and dissipating energy during downward displacement of said proximate ends, but not during upward return to said predetermined elevated position; said stop means comprising a fixed abutment and a co-operating abutment movable downward with said proximate ends; and means for changing the effective level of said fixed abutment to limit downward movement of said axis to a bottom position at a higher level; said means comprising a movable block adapted to be interposed between said abutments when they are sufficiently separated.

19. A track retarder for wheeled vehicles comprising, in combination: two adjacent track sections having their proximate ends in substantial abutment and vertically movable; the remote ends of said sections being supported at substantially constant level; resilient means normally supporting said proximate ends in a predetermined elevated position when not under load; stop means positively limiting the downward movement of said proximate ends; damping means for absorbing and dissipating energy during downward displacement of said proximate ends, but not during upward return tosaid preinoperative automatic means for interposing said 10 1,359,073

block between said abutments; and connections actuated only by a wheel moving in one predetermined direction, for rendering said automatic means operative.

GEORGE C. BELTMAN. DONALD H. SWEET.

14 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 806,147 Hussey Dec. 5, 1905 813,542 Case Feb. 2'7, 1906 1,560,878 Tatum Nov. 10, 1925 Clausen May 17, 1932 FOREIGN PATENTS Number Country Date 481,115 Great Britain Mar. 4, 1938

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