US1981487A - Automatic control for car retarders - Google Patents

Description

'Nov- 20, 1934. s. w. wHl-:RRY 1,981,487

VAUTOMATIC CONTROL FOR CAR RETARDERS Filed Marchl 24, 1953 2 Sheets-Sheet l WlTNESSESMmLZ-z- INVENTOR:

Nov. 2o, 1934. s. w. WHERRY 1,981,487

AUTOMATIC CONTROL FOR CAR RETARDERS Filed March 24. 1933 y 2 sheets-sheet 2 FIC I JZ l J J0 I l l5 5 gg ZM ffl? A xl- 3L 25; ZZ /=:*AY- 7/:26 j

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Patented Nov. 20, 1934 UNHTED STATES AUTOMATIC CONTROL FOR CAR RETARDERS Samuel W. Wherry, Altoona, Pa.

Application March 24,

8 Claims.

My invention relates generally to railway car retarders and particularly to automatic controls for car retarders. The principal object of my invention is the provision of an improved and simplified means for automatically controlling the operating pressure of the retarder in relation to the speed of the approaching car.

Car retarders are commonly used in railway classification yards equipped with humps, and serve as important elements of the system for classifying cars. Cars drifting down from the hump gain considerable momentum and demand regulated control. The car retarder checks the speed of the car at the will of the operator and avoids the necessity of having a man ride the car to operate the hand brake. The braking eiiect is accomplished by pairs of elongated shoes between which the wheels of a car are gripped. Usually there is a selection of pressures to effect varying degrees of retardation. The operator manually controls the operation of the retarder, selecting the degree of retardation according to his estimate of the speed of the approaching car. My invention dispenses with this manual control and completely frees the retarder from the need of an operator in attendance.

A further object of my invention is the provision or" an apparatus of this character which will not only automatically select an operating pressure for the car retarder, but also will automatically maintain such selected pressure while the car is subject to the action of the car retarder.

A further object of my invention is the provision of an apparatus of this character which may be incorporated easily into the usual hand controlled car retarder to provide the automatic feature in addition to the hand control.

Other objects and advantages of my invention will be apparent from the following description of one embodiment or example thereof, having reference to the accompanying drawings.

Of the drawings:

Fig. I shows diagrammatically an automatic control of my invention applied to a car retarding apparatus of a usual type; and,

Fig. II shows a sectional View of the container which houses the mechanical elements of the apparatus including the timing mechanism and the returning mechanism.

In Fig. I or" the drawings there is illustrated a form of automatic control embodying my invention, the particular form shown being connected up with an electro-pneumatic car retarder of a well-known type in general use. It will be obvious that this automatic control may be used in con- 1933, serial No. ceases (c1. 30e-2li) nection with other type-s oi "electrically controlled retarders to achieve the desired results. The particular car retarder here shown is of a common and well understood type and is shown diagrammatically without elaboration or detail.` As in most car retarders, the shoes 1 which grip the wheels of a car are disposed on both'sides of each rail 2. These shoes are actuated by the pneumatic cylinder 3 through a system` of links and levers connected to the shaft if These links andlevers not being necessary to a proper understanding of my invention have been omitted from the drawings. ,The pneumatic actuating cylinder 3 is controlled by an electro-pneumatic valve 5 which is itself controlled by a hand lever 6 through a system of pressure controllers 7. Four retarding pressures are generally used, 25 lb., 50 lb., 75 lb., and the full pressure of about 90 lb.; and the desired one is selected by an operator using therevolving hand switch 6. In the electro-pneumatic valve 5, the admission magnet is designated at 8, the. exhaust magnet at 9, and the release magnet at l0. The main air line is indicated at 11. This comprises generally the apparatus or system into which my invention is introduced.

The mechanical elements of my invention are housed within a container 12, shown in detail in Fig. II, which serves as a supporting framework. Within this container 12 is the selective switch, comprehensively designated at 13, having arevolving arm 14 with contact points 15a, 15b, 150, 15d and 15e, in circular disposition on an end panel 16 of the container 12, as shown in Fig. I. These contact points 15a, 15b, 15o, 15d and 15e, are in the form of segments of a circle and together form a circle with each segment insulated from the others. The panel 16 is of an insulating material, necessarily. A timingmechanism 1'? is used to revolve the selective switch 13 in one direction during an interval commensurate with the speed or" an approaching car;` and a returning mechanism 18 turns the selective switch 13 in the reverse direction at the end of this automatically determinedv interval until it is again in the initial or off position. As soon as the switch 13 reaches this initial position, the mechanically operated cut-out switch 19 which is also withinthe container 12, is opened by the switch arm 14 and the returning mechanism 18 ceases to operate.

Also within this container 12 are two relays 20, 2l which are connected in series with an insulated section of track designated at a. The presence of a car truck on` the section of track a closes this circuit which is energized by a battery 32 and energizes the relays 20, 21. The relay 21 controls the operation or" the timing mechanism 17 which actuates the selective switch 13, the timing mechanism 17 operating when the relay 21 is energized and ceasing to operate when the relay 21 is de-energized. The other relay 20, when energized, breaks the operating circuit of the re-` ated returning mechanism y18 has the doublefunction of returningl the revolving arm 14 to its initialor lorf position and at the same time winding f the spring `of the timingmechanism- 17.

Aclockwise direction as viewed in Fig. I.

The returning mechanism 18 and the timing mechanism .,17 'are geared-to the revolving Varm 14 inrthe following manner, as shown in Fig. II.

v The returningmechanism 18 drives a gear wheel 22 whichmeshes with a gear wheel 23 loosely mounted en .a shaft. 24.-'Carried on the driven gear 23"'is. a swingingpawl 25a which engages a ratchet wheelv 26a Iiixed to the shaft 24.A Inasmuch as the revolving arm 14 is iixed to the shaft 2:4; .the actuation of the returning mechanism 18 through the gears 22, 23,' the pawl.25aand ratchet 26'acauses.the arm v14 to revolve in a counter- Also meshing. withthe driving gear 22 of the returning mechanism 18 is a driven gear 27 mounted on a shaft 28'. Rotation. ofthe shaft 28, incident to theoperatio'n ofthe returning mechanism 18, rewinds the timingmechanism 17.

The timing mechanism 17 drives a gear wheel 29which mesheswith an idler gear 30, the latter in' Vturn meshing .with a gear Wheel 31 loosely mounted on the shaft .24. Carried ony the driven gear'Bl. lisla swinging pawl 25h vwhich ,engages axratchetwheelZb' xed to theshaft 24. Actuation'ofthe'timing mechanism 17 causesthe arm 14 ltorevvolv'eina clockwise direction as viewed inf-lFigqI. The timing mechanism 17 is directly responsive'to the action of the relay 21. When the'relayt21`is energized, the armature G0, shown in Fig-. I,"israise.d, 'carryingwith it a pawl 6l and disengaging the, pawl 61 from the ratchet wheel 62; Thisimmediately starts the clockwork mechanism:- When-the relay 21 is'de-energized, the arma-ture' Afalls,` and the pawl Slengages 'the ratchetwheel 62"stopping the clockwork 'mechanism; Thel clockwork `mechanism is of an ordinary"type;*andneedsrno detailed description.

Thecircuit-'controlled fby the relay 20 includes the battery-'50, `the cuteoutiswitch 19 and the returningI mechanism l8. The cut-out 'switch 19 is lbestunderstood vby reference to Fig. I. When the arm=`14 returns/to' the initial or off position, thel projection on the extremity of the arm 14 separates theelectricalcontacts 34 which are normally-pressedginto mutual engagement by a spring-orj-theA like;` This causes a break in the operating circuit of the returning mechanism 18. When-the arm 14 under'the influence of the clockwork `mechanism 17 leaves the initial or oi positiom-the contacts 34 close' and the circuit is prepared `for `closing-"upon de-energization` of the relay 20.A Astop-S 'limits the'movement of the arm 14 and determines its initial or ofi position.

Contacting with the revolving arm 14 is a brush 38 mounted on a bracket 37. The brush 36 serves to complete the circuit between a wire 38 and the segments 15e, 15b, 15C, 15d, 15e, over which the arm 14 travels. The wire 38 is in turn connected through a resistance 89 to a wire 40 which leads to a battery 41 in the operating circuits for energizing the electro-pneumatic valve of the car retarder cylinder 3.

Relays 420 42o, 42o, 42d, 42e, which I prefer to call completing relays, are in circuit with WireswiSa,A 43h, 43C, 48d, 43e, respectively, and these relays selectively control the operation of the retarder cylinder 3, performing automatically the functions which heretofore were performed manually by the hand control lever 6. Each relay 42a, 42h, 42o, 42d, 42e, connects with a binding post 47, and each binding post 47 is attached to one4 of the. segmental contacts 15a, 15b, 15e, d, 15e. ,The operating circuits are completed in predetermined order by the successive engagements of the revolving arm i4 with the conia, 15b, 15o, 15d, 15e. Consequently, the f iving arm i4 selects which circuit shall control, and the operation of the car retarder is governed accordingly, the'iunction of *each of the relays 42a, 42h, 42e, 42d, and 42e, on being energized,` is to close its circuit without further need oi'the selective switch and hence to continue this circuit in its completion after the selective switch 13 is returned to its initial position by the returning mechanism `18. In conjunction with each of these-completing relays 42a, 42h, 42e, 42d, 42e, is a sustaining relay, the sustaining relays being designated respectively at 44a, 44h, 44o, 44d, 44e. The five sustaining relays are all in series, ina `circuit energized by a battery 48. This circuit is normally, open' and is connected with a second insulated section of track designated at b continuous with the insulated section a mentioned above, but insulated from it` as indicated at 49. The presence of a car truck on the insulated section Z2 closes the circuit and energizes the ve sustaining relays. The section of track b is coincident with the space covered by the retarder shoes l. The effect of thus energizing the iive sustaining relays is that only that completing relay which is closed when the sustaining relay circuit is energized will be held closed during the operation of 'the `car retarder. 'Ihe other four completing relays which are open will be unaffected.

Each of the :five operating circuits a particular function assigned to it. The circuit associated with the completing relay `42o; operates the brake release and is connected by a binding post 47 to segmental contact 15a of the selective switch 13, the contact with which the revolving arm 14 contacts in its initial or olii position. Proceeding in the direction or" rotation ci the revolving arm 14 when it is actuated by the timing mechanism 17, the next segmental contact 15b connects with the full pressure (98 lbs.) operating circuit associated with completing relay 42h. Continuing in the saine direction oi rota-- tion, the segmental contacts 15e, 15d, 15e of the selective switch connect with lower pressure operating circuits in the order ci decreasing pressures, the 75 lh. operating circuit being associated with completing relay 42e, the 50 lb. operating circuit with relay 42d and the 25 lb. operating circuit with relay 42e. The brake release circuit, associated with relay 420;, traces directly to the brake release magnet l0 of the electro-pneumatic valve 5. The lb., the 50 lb., and the 25 1b. operating circuits associated with relays 42e, 42d and 42e, respectively, trace to the corresponding pressure controller 7 and from it to the admission magnet 8 of the electro-pneumatic valve 5. The full pressure circuit associated with relay 42h traces directly to the admission magnet 8.

The operation of the herein described car retarding apparatus with automatic control will be explained by assuming a car to be approaching from the direction indicated by the arrow, see Fig. I. The revolving arm 14 of the selective switch 13 is in its initial or off position, and the retarder brake shoes 1 are released. When the leading truck of the car passes onto approach section a of the track, the relays 20, 21 are energized through the completion of the circuit in which they .are connected bythe passage of the leading car truck therealong. Operation of the relay 21 causes the timing mechanism 17 to start and the arm 14 of the selective switch 13 begins to revolve. The relay 20 atthe same moment has opened the operating circuit for the returning mechanism 18, preventing the operai sition of the relay 20.

As the revolving arm 14 revolves in a clockwise direction as indicated by the arrow in Fig. I, the contacts 15d, 15b, 15o, 15d, 15e, are successively engaged. Each completing `relay 42a, 42h, 42C, 42d, 42e, is closed in turn and opens again as the revolving arm 14 breaks the contact. As soon as the leading car truck passes onto the insulated section of track b, all the sustaining relays 44, 44h, 44e, 44d, 44e are energized and that completing relay which is energized and closed at that moment is held closed by one of the sustaining relays.

If it be assumed that the car has approached the car retarder at the maximum speed which it can obtain, the revolving arm 14 will be in contact with the segment 15b just before the forward truck passes from track section a to track section b. Current will pass from the battery 41, through wire 40, resistance 39, wire 38, brush 36, revolving arm 14, and the segmental contact 15b to completing relay 42h, thence through wire 43h, admission magnet 8, and the common wire 45 to the other side of the battery 4l. Completing relay 42h will therefore be energized at this moment, and maintained momentarily in the up position, whereas all of the other completing relays will be de-energized and in the down position. At the moment when the forward car truck passes onto section b of the track, and the sustaining relays 44a, 44h, 44e, 44d, 44e, are consequently energized, completing relay`42b will be caught in the up position and there held by the sustaining relay 44h. It will be noted'that as soon as completing relay 42h is picked up, current may pass directly from the wire 40 through a wire 46 to the contact of relay 42h and thence to wire 43h. The resistance 39 causes the current' to be shunted away from the circuit through the revolving arm. Hence so long as the sustaining relays are de-energized, the completing relays will be picked up and then immediately dropped, and then picked up again, but as soon as the sustaining relays are energized, one and only one completing relay will be caught in the up position and there held. v

vAt the moment when the forward car truck passes onto section b of the track, the relays 20, 21 are both de-energized. Accordingly, the timing apparatus ceases operation, while the returning mechanism 18 begins operation. The revolving arm 14 is then turned in a counterclockwise direction, as viewed in Fig. I, until it has reached its initial or off position. As the revolving arm approaches the stop 35 its projection 33 separates the contacts v34 of the cut-out switch 19 and opens the circuit to the motor of the returning mechanism which then ceases to operate.

From the above description it will be apparent that the particular operating circuit for the car retarder selected by the selective switch 13 depends upon the speed of the approaching car. Upon the assumption that the full pressure (90 lbs.) circuit has been selected, the cylinder 3 will be operated at that pressure, until the circuit to the sustaining relays is broken by the passage of the car truck off the track section b. The contacts 15d, 15b, 15e, 15d, 15e, being arranged in the descendingo'rder of pressures to which they correspond, the longer the revolving arm 14 is actuated by the timing mechanism l7,\the lower will be the pressure selected.' I-lence when the speed of the approaching car is great, the time interval for the passage of the car over the approach track section a will be short; and the shorter this time intervalis, the lgreater will be the pressure exerted by the shoes 1 to retard the car. Before the rear car truck of the car reaches the car retarder station, the revolving arm 14 is returned by the returning mechanism` 18 to its initial or off position. Accordingly, when the rear truck passes onto the approach track section a, the operation of the car retarding apparatus is repeated upon the rear truck, the pressure selected depending upon the speed at which the rear truck passes over the approach track section a. The apparatus is so designed that by the time both car trucks have passed through the car retarder, the speed of the car'will have been reduced to the desired amount.

If for any reason it is desired to disconnect the automatic control feature of my invention and to utilize manual control, this can be readily accomplished by opening the switch 49 and manipulating the revolving hand switch 6.

While my invention has been described in some detail with reference to a specic embodiment thereof, it will be apparent that various changes may be made in the form of the apparatus herein described without departing from the spirit of my invention as dened in the annexed claims.

' Having thus described my invention, I claim:

l. The combination with a car retarder including the mechanism for applying same at different pressures, of an automatic control for said mechanism comprising a plurality of operating circuits, each of said circuits operating said car retarder at a diierent predetermined pressure, a selective switch. operated by a car actuated timing mechanism to select. and complete one of said operating circuits in accordance with the speed of anv approaching car, car actuated sustaining means for holding the selected circuit in completion independently of said selective switch until said car haspassed through the car retarder, and means for returning said selective switch. to its initial position.

2. The combination with Va car retarder including the mechanism for applying same at different pressures, of an automatic control for said mechanism comprising a plurality of operating circuits; each; of. said. circuits operating isa-idear retarder. at ya vdifferent predetermined pressure, Ua selective switch operated'- by a car .actuated 'timing mechanism-:to select and completefonefoisaid operating circuits'in accordance with .the speedv pressures, of an automatic control for said; mech;

aniram-comprising Ya plurality ofoperating-circuits, each ofl said circuits operating said fcar re= tarderata different predetermined pressure, a selectiveswitch `operated by a car actuated timing mechanism .to select and complete one of' saidoperating circuits in accordance ,with the vspeed of.:an approachingcar, car actuatedL sustaining means=for holding the selected-'circuit independently of' said selective switch until said 'car has passed: through the car retarder, and car actuated meansfor returning said 'select-ive switch vto .302, its initial positionwhile saidselected circuit is vlect'andcomplete one of said operatingl circuits` in accordance'with the -speed `of an .approaching car, car actuated sustaining--means` foruholding the selected circuit in completion'independently of said selective switch until said cart has passed through the car retarden-andlmeans-for returning: said selective switch ,f to. its initial position.-v

5. The combination with a car retarder including the mechanism. for applying thesame at different pressures, of an .automatic vcontrol for said mechanism .comprising a plurality vof operatingcircuits, -each yof said circuits-'operating said car -retarder at -a different: predetermined pressure, aselective switch operated by a.car actuated mechanism to select and'complete one of saidl operating circuits in accordance with the speed-,of the approaching car, a completing vrrelay in each of said circuits for closing a normally open contact when that circuit is energized, thereby shunting said `selective switch, a sustaining relay in conjunction with each` said completing relay, said sustaining relays being connected in series in a normally open circuit, an insulated section of track coincident with the limits .of said kcar retarder forming part of said normally open circuit, said circuit being closed 'during vthe Apassage of afcar along said section of track, and a car actuated means for returning said Aselective switch to the initial position..

6. The combination with a car retarder including the mechanism for applying same at different pressures, of an automatic control for said mechanism 'comprising a plurality of operating circuits, each of .said circuitsI operating said car retarder at a :different predetermined pressure, a selective v Switch adapted tol select one of `said opera-ting` circuits-,in Vaccordance with :the speed of arr z'approaching-,fcan 'a :relay for.' controllingihe operation of 'said selective switch, .a returning mechanism for returning said selective switchto its initialposition, a second -relay for Icontrolling .the operationl ofA said returning imechanismysaid relays being in series in a 'circuit normally open, an insulated section of track in advance ofcsaid car retarderformingva partof ysaid opencircuit, said circuit being closed kduring -the passagezof .a car.v along said section of track, a cut-out switch iii-'series with said second-relay fopen only when said selective switch is in the initial pQStiomsaid second relay and said cut-out switch so operating that'the returning mechanism will vbe--set in motion; whena -car leaves saidinsulated section `of track` and cease to "operate whenfsaidrselective switch has returned yto theinitial position, and a can actuated yrelay which will hold said selected circuitaiter said operatingswitch has started-its return to theinitial .position and until fsaid car hasleft thecar retarder.

7. .The combination with a car retarder including the mechanism for applying same at different pressures, of an automatic, control for said yrnechanisin comprising a plurality or operating circuits, a selective :switch having a revolving arm making contact with points in circular disposition, the :contact with each point completing vone of said operating circuits, an operating :mechanism for said revolving arm'motivated by a spring, a .return operating mechanism :for returning said revolving arm to its initial position and Winding said vspring mechanism at the same time," two relays in series in an open circuit of said-operatingand returning mechanism, an insulated'section of Vtrack inadvance of said car retarder, said section being connected with said opencircuit so that-.a oar truck on said section will close the circuit and .energize said relays, one of said relays causingthe spring mechanism to turn said switch arm so long as a car truckis on said .insulated section, and the other of said relays preventing said' returning mechanism from yoperating so long as fa :cantruck is `on said .insulated section vof trackyfa cut-out switch whichstopsth'e actionof said returnmechanism whensaid .revolving arm has returned to the initial position, and ak sustaining relay in each saidcontrol circuit actuated by the presence of a car onzthat section of track coincident with saidcar retarderforfholding the circuit last selected by said revolvable switch `arm as the last truck of said car leaves said insulated approachA section of track and until the last truck of said .car has left the car retarder. V y

8. The combination .witha carretarderincluding the mechanism for operating same at different pressures, of an automatic control for said mechanism, .comprising a. plurality of operating circuits-each of said circuits operatingsaid car retarder atia diierent predetermined pressura'a selective switch having a revolving switch arm and about its axis, contact points in 'circular disposition, said operating circuits being so connected with said switch that as said switch arm rotates from the off .position each of said circuits will be 'closed in rthe inverse .order of thel pressures they control, an operating mechanism'for said'-.selective-switch, .a relay connected withan 'M insulated section of track in advance of said .car retarder for controlling and timing: the period of operation of said selective switchzmechanism, a returning mechanism for returningr said revolving switch arm toits off position, a relay-connecter) i said control circuits, a sustaining relay which holds the circuit last selected as the last car truck leaves said approach section of track, and maintains the completion of said circuit until the last truck of said car has left the car retarder.

SAMUEL W. WHERRY.

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