US2320802A - Railway braking apparatus - Google Patents

Railway braking apparatus Download PDF

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Publication number
US2320802A
US2320802A US424338A US42433841A US2320802A US 2320802 A US2320802 A US 2320802A US 424338 A US424338 A US 424338A US 42433841 A US42433841 A US 42433841A US 2320802 A US2320802 A US 2320802A
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United States
Prior art keywords
relay
contact
relays
circuit
lever
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US424338A
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English (en)
Inventor
Clarence S Snavely
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Hitachi Rail STS USA Inc
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Union Switch and Signal Inc
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Priority to BE477760D priority Critical patent/BE477760A/xx
Application filed by Union Switch and Signal Inc filed Critical Union Switch and Signal Inc
Priority to US424338A priority patent/US2320802A/en
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Publication of US2320802A publication Critical patent/US2320802A/en
Priority to FR952842D priority patent/FR952842A/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61K—AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR
    • B61K7/00—Railway stops fixed to permanent way; Track brakes or retarding apparatus fixed to permanent way; Sand tracks or the like
    • B61K7/02—Track brakes or retarding apparatus
    • B61K7/12—Track brakes or retarding apparatus electrically controlled
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61K—AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR
    • B61K7/00—Railway stops fixed to permanent way; Track brakes or retarding apparatus fixed to permanent way; Sand tracks or the like
    • B61K7/02—Track brakes or retarding apparatus
    • B61K7/04—Track brakes or retarding apparatus with clamping action

Definitions

  • My invention relates to railway braking apparatus, and particularly to car retarders of the type comprising wheel engaging braking bars located beside a track rail and movable toward and away from the rail into braking and nonbraking positions. More particularly, my invention relates to apparatus of the type described wherein the braking bars are arranged to be moved to their braking positions by means of one or more fluid pressure motors, and to be restored to their non-braking positions by suitable biasing means.
  • One object of my invention is the provision of improved means for automatically controlling the braking action of a car retarder in accordance with the speed of a car passing therethrough.
  • Another object of my invention is the provision of improved timing means for measuring the speed of a car passing through a car retarder.
  • Another object of my invention is the provision of improved means for progressively decreasing the braking force exerted by a car retarder as the speed of a car being retarded by the retarder approaches a selected one of a plurality of predetermined control speeds, and for releasing the retarder when the selected control speed is reached.
  • a further object of my invention is the provision of means whereby the braking action of r a car retarder may be controlled automatically in accordance with the speed of a car passing through the retarder, or manually at the will of an operator.
  • a still further object of my invention is the provision of means for providing improved flexibility of operation of a fluid pressure operated car retarder by enabling the pressure which is supplied to the retarder to operate it to be graduated into manually selected levels.
  • the stretch of track with which the retarder is associated is provided with a series of single rail track circuits each of which includes an insulated rail section which is sufficiently short so that two wheels of a car cannot occupy the section at any one time.
  • Each track circuit includes a track relay, and a back contact of all of the track relays in advance, whereby only one track relay will be energized. at a time. sets into operation time measuring means comprising a source of constant frequency alter nating current, and means for counting the cycles of this source.
  • the source includes a pair of half-step relays which respond to alternate half cycles of the current, whereby each relay operates once during each cycle of the alternating current, and a unit chain of counting relays which pick up successively one each time a selected one of the half-step relays operates.
  • the counting relays are arranged to continue to operate as long as the track relay which initiated their operation remains energized. Assuming that the frequency of the constant frequency source is 60 cycles, and that the unit chain includes 6 relays, it will be seen that successive relays of the unit chain will pick up at intervals of 16 milliseconds, and the chain will complete a full cycle of operation every 100 milliseconds.
  • the time measuring means also includes a multiple chain of counting relays so arranged that the relays of this latter chain will advance progressively one each time the unit chain completes a round trip of operation.
  • the time measuring means further includes means for restoring the counting chain to starting position to initiate a new timing period each time a new track relay picks up.
  • the relays of the unit and multiple chains control other relays for effecting a graduated reduction in the pressure of the fluid applied to the operating cylinder of a fluid pressure operated car retarder in accordance with the setting of a manually operable lever to cause the retarder to release when the speed of a car has been reduced to a selected speed.
  • the apparatus also includes means whereby the retarder can be controlled manually independently of the manually operable lever.
  • Figs. 1a and lb are views which, when placed one above the other with Fig. 1a on top in such manner that the dotted lines leading to the bottom of Fig. 1a align with the dotted lines leading to the top of Fig. 1b, together constitute a view partly sectioned and partly diagrammatic illustrating one form of apparatus embodying my invention.
  • Figs. 2a and 2b are views similar to Figs. 1a and 1b illustrating another form of apparatus embodying my invention.
  • Fig. 3 is a table showing the method of connecting the front contacts of certain ones of the relays forming part of the apparatus illustrated in Figs. 1a, 1b, 2a and 2b to obtain predetermined control speeds.
  • the reference characters I and la designate the track rails of a stretch of railway track over which cars normally move in the direction indicated by the arrow under such conditions that it is desirable to at times control the speed of the cars automatically.
  • the stretch of track here shown might be in a classification yard of the hump type through which cars move under the influence of gravity. It is obvious that in service of this kind the speed of individual cars or strings of cars will vary through wide limits depending among other things on the speed at which they go over the hump, the temperature,
  • a car retarder CR which in the form here shown comprises two braking bars 2 and 3 extending parallel with, and located on opposite sides of rail I, and two similar braking bars 2a and 3a extending parallel with and located on opposite sides'of rail Ia.
  • the braking bars 2, 3, 2a and 3a are operated by a fluid pressure motor M (Fig. lb) comprising a cylinder 4 containing a reciprocable piston 5 attached to one end of a piston rod 6.
  • the braking bars 2, 3, 2a and 3a are operatively connected with the piston rod 6 through a suitable linkwork here shown as comprising a bell crank I and a lever 8 pivotally supported at point 9.
  • a suitable linkwork here shown as comprising a bell crank I and a lever 8 pivotally supported at point 9.
  • the braking bars 2, 3, 2a and 3a are constantly biased to their non-braking positions by any suitable means, here shown as a spring III which is interposed in the cylinder 4 between the righthand end of the cylinder and the piston 5.
  • a spring III which is interposed in the cylinder 4 between the righthand end of the cylinder and the piston 5.
  • the motor M is controlled by two magnet valves VI and V2, each comprising a valve stem I2 biased to an upper position by means of a spring I I, and provided with an armature I3 and a winding, I4.
  • valve VI When valve VI is energized, as shown in the drawings, valve stem I2 of this valve is moved downwardly against the bias of spring I I, and a pipe I8 which communicates with the left-hand end of motor M is then connected with atmosphere through a port I5.
  • valve VI is deenergized, however, pipe I8 is disconnected from atmosphere. and is connected with a pipe I6 leading to valve V2.
  • valve stem I2 of this valve moves downwardly, and connects pipe I6 with pipe I I which is constantly supplied with fluid pressure, usually air, from a suitable source not shown in the drawings, but when valve V2 is deenergized, as shown in the drawings, pipe I6 is then disconnected from pipe I1. It will be apparent, therefore, that when valve VI is energized,
  • valve VI When, however, valve VI is deenergized and valve V2 is energized, fluid pressure wil1 be supplied to the left-hand end of cylinder 4 of motor M, thus causing the braking bars to move to their effective or braking positions. It will be obvious that when the braking bars are moved to their braking positions, they will exert a braking force which is proportional to the pressure of the fluid which is then supplied to the left-hand end of motor M.
  • the valves V are controlled in part by a plurality of pressure responsive devices PHI-30 and P45-55, each comprising a Bourdon tube 2I connected to pipe I8 and hence subjected to the pressure of the fluid in the left-hand end of motor M.
  • Each Eourdo-n tube controls two contacts 2222a and 22--22b.
  • the pressure responsive devices P253il and PA E-55 are so constructed and so adjusted that they will operate successively as the pressure in the region of cylinder I between the piston 5 and the left-hand end of the cylinder increases. For example, for all pressures below 20 pounds per square inch, the contact 22-2 2a of each of these devices is closed.
  • valves V are also controlled in part by a plurality of relays IPO, 2P0, IPZiI-M, 2P2lI--30, IP45-55 and 2Pl555 which relays, in turn, are controlled by speed responsive apparatus in a manner which will be described in detail hereinafter.
  • valves V are further controlled by means of a manually operable lever L which, a here shown, is capable of assuming five positions, indicated by dotted lines in the drawings, and designated by the reference characters P0 to 124, inelusive.
  • a manually operable lever L which, a here shown, is capable of assuming five positions, indicated by dotted lines in the drawings, and designated by the reference characters P0 to 124, inelusive.
  • Operatively connected. with the lever L are a plurality of contacts 25, 26, 21, 28 and 29.
  • Contacts 25, 26, 21 and 28 are closed, respectively, in the 100, pl, 122 and p3 positions of lever L, while contact 29 is closed in the pl position, the p4 position, or any position intermediate these two positions.
  • the lever L will usually be located at a point remote from the braking apparatus, as in the control cabin of a classification yard car retarder system, and will be connected with the braking apparatus by means of line wires extending from the control cabin to the braking apparatus.
  • the previously mentioned speed responsive apparatus for controlling relays IPIJ, 2P5, I P2ii-3Il, 2P253!J, IP4555 and 2P45-55 comprises a series of relatively short insulated control sections IT, 2T, 3T, 4T, 5T and ET, which control sections are formed in the rail I.
  • These control sections will usually be of uniform lengths, .and their lengths may be varied as conditions require, but the lengths of these sections will preferably be such that two wheels of a car cannot occupy the same section at any one time.
  • a preferred length for these sections is 3 ft. 1 /2 in.
  • each control section is a track relay designated by the reference character B with a prefix corresponding to the reference character for the associated section.
  • These track relays are sensitive quick acting relays, and each relay is connected in a track circuit which, when all of the track relays are initially deenergized and a pair of wheels moves onto any one of the track sections T, includes a suitable source of current here shown as a battery 30, a back contact 34 of a relay ZSU, a back contact 33! of a relay ISU, a back contact 3! of each of the track relays in advance of the occupied section, the winding of the track relay of the oc cupied section T, the wheels and axle of the pair of wheels on the occupied section T, and the rail Ia.
  • relay ISU will pick up and will open its front contact 33I, but track relay ITR will be maintained in its energized condition after front contact 33
  • the speed responsive apparatus also comprises means for measuring the time during which any of the track relays is energized to thereby provide a measurement of the speed of the car.
  • this time measuring means comprises a suitable source of constant frequency alternating current, illustrated in the drawing as an alternator A, and means for counting the cycles of this source.
  • the source of alternating current will generally comprise the usual commercial power source.
  • the means for counting the cycles of alternating current includes two half-step relays PX and NX of the quick acting two winding polar magnetic stick type and two oppositely poled half wave rectifiers 334 and 35.
  • the one winding 31a of relay PX is connected with alternator A over a front contact 36 of a relay W, the rectifier 334 and a normal contact 38 of relay NX, while the other winding 31b of relay PX is connected with the alternator A over front contact 36 of relay W, rectifier 334, and reverse cont-act 39 of relay NX.
  • the winding 31!: of relay NX is connected with alternator A over front contact 36 of relay W, rectifier 35, and a normal contact 40 of relay PX, while the other winding 31b of relay NX is connected with alternator A over front contact 36 of relay W, rectifier 35 and reverse contact 4
  • the rectifier 334 is poled to pass current during positive half cycles only, while the rectifier 35 is poled to permit current to flow during negative half cycles only.
  • the relay W is controlled by the track relays R in such manner that this relay willbe energized whenever any one of these track relays is energized, by virtue of, circuits which I shall describe shortly.
  • the relay NX is provided, in addition to the previously mentioned normal and reverse contacts 38 and 39, with a normal contact l24?.a and a reverse contact 42-4227. Assuming for purposes of illustration that the alternator A has a frequency of 60 cycles, it will be apparent that when the relay NX is operating, these contacts will become alternately closed at intervals of of a second or 16 milliseconds. This rate will vary only to the extent that the frequency of the alternator A varies, which variation will be extremely small, particularly if the alternator A comprises a commercial source of power.
  • the cycle counting means also comprises a unit chain of counting relays III to 6U arranged to pick up successively in response to the alternate operation of the contacts 42- i2a and 4242b of relay NX, and a multiple chain of counting relays GM to 5M arranged to advance progressively one each time the unit chain completes a round trip'of operation.
  • the relays of both chains are of the quick acting neutral type.
  • a relay MX of the two winding polar magnetic stick type which serves to make the selection of the circuits for the relays of the multiple group necessary to cause them to pick up in succession in response to each round trip of operation of the unit chain, and a similar relay UX, the function of which will be made clear presently.
  • the operation of the timing means as a whole is as follows: When the track relays T are all deenergized, as is the case when no car is traversing the stretch of track shown in the drawing, the relays of both timing chains, and the associated relays W, ISU, ZSU, NX, PX, MK and UK are all deenergized.
  • relay ITR When a car starts to traverse the stretch of track shown in the drawing, relay ITR will pick up first for reasons which will be apparent from the foregoing description, and the picking up of this relay will complete a circuit for relays W, ISU, ill and the winding 4-8 of relay UK in series, which circuit may be traced from the terminal B of a suitable source of direct current not shown in the drawings, through the winding of relay W, a back contact 3333b of each of the track relays ETR, ETR, 4TB, 3TB, and 2TB, front contact 3333a of track relay I'I'R, the winding of relay ISU, a back contact 44 of each of the relays 2U to 6U, inclusive, of the unit counting chain, a back contact 45 of each of the relays BM to 5M of the multiple counting chain, winding 48 of relay UX, wires 4t and 41, and the winding of relay lU to the other terminal C of the source. Relays W, ISU and [U will therefore pick up immediately,
  • relays Ill and ISU completes a stick or holding circuit for these relays passing from terminal B through the winding of relay W, a back contact. 33-431) of each of the track relays 6TB, 5TB, 4TB, 3TR and 2TB, front contact 3333a of track relay ITR, the winding of relay ISU, front contact 49 of relay ISU,
  • relay W completes at its front contact 35 the previously described operating circuits for the relays PK and NX and these relays therefore start to alternately operate on alternate half cycles of the alternator A in the manner described hereinbefore.
  • relays W and IU are both picked up when the relays NX and PX start to operate, the first time reve se contact 4242b of relay NX becomes closed, it completes a pick-up circuit for relay 2U passing from terminal 13 through front contact 43 of relay W, reverse contact 42-421) of relay NX, wire 55, front contact 54 of relay IU, and the winding of relay EU to terminal C.
  • Relay 2U therefore picks up and interrupts at its back contacts 444 and 52, respectively, the previously described pick-up and stick circuits for relay l U, and completes at its front contact 53 a stick or holding circuit which is similar to the previously traced stick circuit for relays ISU and !U with the exception that this latter circuit includes a back contact 52 of relay 3U, front contact 53 of relay 2U and the winding of relay 2113 in place of a back contact 52 of'relay 2U, front contact 53 of relay H17, and the winding of relay lU.
  • Relay 9U therefore, now becomes deenergised, while relay 2U remains energized as long as relay 3U remains deenergized.
  • relay 3U which is similar to the corresponding pickup circuit just traced for relay EU, and which ill therefore be apparent from an inspection of the drawing.
  • Relay 3U therefore picks up and interrupts both the pick-up and stick circuits for relay 2U which causes relay EU to release.
  • the picking up of relay 3U also completes a pickup or holding circuit for this relay similar to the previously traced pick-up or holding circuit for relays NJ and 2U.
  • relay 4U When relay NX next closes its reverse contact, relay 4U will pick up and relay 3U will release, and when relay NX next closes its normal contact, relay EU'will pick up and relay .U will release and so on, until a complete cycle of operation of the unit chain is completed.
  • relay IU will again pick up by virtue of circuit connections between the tU and IU relays similar to those between any two succeeding relays of the chain, and will start the operation of the chain over again. It will be seen, therefore, that the relays ill to EU will continue to climb around and around as long as track relay I TR, remains energized.
  • relay ISU in addition to being included in the previously described stick circuits for the relays IU to (ill, is also in cluded in a pick-up circuit for the starting relay OM of the multiple chain, which latter circuit may be traced from battery B through the winding of relay W, back contact 33-331) of each of the track relays GTR, 'I'R, 4TH, 3TB.
  • relay OM With relay OM picked up, when relay 3U picks up during the first round trip of operation of the unit chain, it will complete at its front contact 64 a circuit for the one winding 65 of the transfer relay MK, and this relay will thereupon open its normal contact 66-66a and will close its reverse contact 66--6Bb.
  • This circuit includes in addition to front contact 64 of relay 3U, front contact 63 of relay OM, as will be obvious from an inspection of the drawings.
  • the circuit will bei come opened as soon as relay 3U releases, but since relay MX is of the magnetic stick type, contact 66-6622 will remain closed until this relay is again energized in the direction to close its normal contact.
  • Relay IM thereupon picks up, and completes a stick circuit passing from terminal B through the winding of relay W, back contact 33-33b of each of the track relays BTR, 5TB, 4TH, 3TB and 2TB, front contact 33--33a of track relay ITR, the winding of relay ISU, front contact 49 of relay ISU, wire 50, a, back contact 60 of each of the relays 5M, 4M, 3M and 2M, a front contact El of relay IM and the winding of relay IM to terminal C.
  • This stick circuit serves to retain relay IM energized after relay 8U releases as will be obvious.
  • relay 30 picks up during the second round trip of operation of the unit chain, the resultant closing of contact 64 completes a circuit for the other winding 68 of relay MX including front contact 63 of relay IM, and relay MX then opens its reverse contact lit-66b and closes its normal contact 6666a.
  • the multiple chain will advance its action by one relay, Accordingly, assuming that the frequency of the alternator A is 60 cycles so that the unit chain completes a round trip of operation each milliseconds, the picking up of each progressive relay of the multiple chain represents a period of 100 milliseconds.
  • provision is made for counting up to 500 milliseconds by the picking up of the M relays, after which, of course, another 100 milliseconds may be counted by permitting another round trip of the unit chain, making a total of 600 milliseconds with the circuits as shown.
  • relay MX merely serves to make the necessary circuit selection of the M group of relays so that each pick-up action of the EU relay of the unit chain will advance the multiple group of relays by one relay.
  • the function of the hereinbefore referred to stick circuit for relay IU, and of the stick circuits for each of the other U relays of the unit chain is to maintain these relays energized during the interval of time which elapses between the opening, at contact 42-42a or 42-421) of relay NX, of the pick-up circuit for the relay whose stick circuit is then closed and the picking up of the relay next in advance in the chain.
  • the stick circuits for the relays of the multiple chain similarly serve to maintain the M relay which last became energized in its energized condition during the interval which elapses between the opening of its pick-up circuit at contact 6666a or 66'o6b of relay MK, and the picking up of the relay next in advance.
  • the stick circuits for both chains function to keep the chains in operation as long as the track relay which started the operation remains energized.
  • a pick-up circuit for relay EU is completed at front contact 3333a of track relay 2TB and current flows from battery B through the winding of relay W, a back contact 33-431) of each of the track relays 6TH, TB, 4TB and 3TB, front contact 3333a of track relay 2TB, the winding of relay ESU, back contact 10 of each of the relays 2U to EU, inclusive, a back contact H of each of the relays OM to 5M, inclusive, the winding T2 of relay UX, wire 46, and the winding of relay ill to terminal 0. Since relays ISU and W are both included in this circuit, these relays and relay I U all pick up. Furthermore, since the winding 12 of relay UX is included in this circuit, this relay reverses its armature, thereby opening its normal contacts and closing its reverse contacts.
  • relay ZSU When relay ZSU picks up, it completes a stick circut for relay IU, and a pick-up circuit for relay OM which circuits are similar to the circuits which were completed by relay ISU following the picking up of track relay ITR with the exception that these latter circuits each include a front contact 33-3311 of track relay ZTR, the w nding of relay ZSU, and front contact 13 of relay ZSU in place of front contact 33-331 of track relay ITR, the winding of relay ISU, and front contact 49 of relay ISU.
  • relay W When relay W picks up, it sets the counting chains into operation, and these chains then function to measure the time required for the pair of wheels of the car to traverse section 2TB in the same manner as these chains functioned to measure the time for the forward pair of wheels of the car to traverse section IT.
  • the circuits for the various relays of the two counting chains Will all be similar to those previously described except for the fact that each stick circuit will now include front contact 33-33a of track relay 2TB. the winding of relay 2SU and front contact 13 of relay 2SU in place of front contact SIB-33a of track relay ITR, the winding of relay ISU and rent contact 49 of relay ISU.
  • the relay ISU When track relays 3TB and 5TB subsequently pick up, the relay ISU will be picked up and the apparatus will function in the same manner as when relay ITR was picked up. Similarly, when the relays 4TB and 6TB pick up the apparatus will function in the same manner as when relay ZTR is picked up. It Will be seen, therefore, that as a car advances through the track circuited territory, the relays ISU and ZSTJ alternate in their action depending upon whether an odd or an even-numbered track relay is then picked up. Each SU relay checks that all relays of both counting chains have become deenergized before it can pick up after which the IU relay of the unit chain picks up for the beginning of a new timing period.
  • the back contacts 33! and 34 of the ISU and ZSU relays are included in the pick-up circuits for the track relays for check purposes. As long as the track relays become successively energized, the multiple front contacts of the track relays by-pass the back contacts of the SU relays and accordingly freely permit the relay next in advance to pick up. After the leading car axle leaves section 6T, it will be apparent that the relay 6TB. will have to release before any of the other track relays in the rear can pick up. Accordingly, all other multiple front contacts of the track relays are then opened, and it is then necessary that both SU relays be released in order that their back contacts 33!, and 34 may close and permit another track relay in rear of track relay 6TB to pick up. This check is provided in order to prevent the counting relays from doubling back to another section without first having been reset to the starting point.
  • the function of the W relay is to provide the necessary separate contacts for supplying operating energy to the NX and PK relays and to the counting chain during the energized periods of the track circuits.
  • the alternating current source and associated half-step relays may be replaced by any suitable motor means which will alternately close the contacts 42-420, and 42- 322) at a known fixed rate.
  • the particular relays 0f the unit and multiple chains which are picked up at any one time are a measure of the time that any section which is then functioning as a measuring section has been occupied. It will also be obvious that since the sections have a known fixed length, the speed of a car passing through the car retarder can be determined from the time during which a section is occupied by a pair of wheels. It follows, therefore, that the relays of the counting chains which are picked up when a pair of wheels vacates a section which is then functioning as a measuring section serve as a measure of the average car speed while the car is traversing a length equal to the lengths of the measuring sections. For example, assuming that the track sections T are all 3 ft. 1 in.
  • relays lP lfi-55, iP2ii3-il and IPO constitute one group of relays
  • relays EP-iS-ES, 2P2i!3t and 2P0 constitute another group of relays, for so controlling the valves Vi and V2 as to eifect an automatic stepped reduction in the pressure of the fluid supplied to the motor M as the speed of a car passing through the car retarder approaches a predetermined control speed which depends upon the setting of lever L, and for effecting the full release of the retarder when this particular control speed is reached.
  • each P relay is provided with a diiierent control circuit for each of the pl, 112 and p3 positions of the lever L, making three control circuits for each relay.
  • the control circuits for the IP and 2P relays are similar except for the fact that each control circuit for each of the lP relays includes a normal contact of the UK relay, whereas each control circuit for each of the 2P relays includes a corresponding reverse contact of the UX relay.
  • control circuits may be varied as conditions require, but as shown in the drawing they are so arranged that when lever L occupies its pl position, which position I shall term for convenience its high speed position, relay
  • relay IP55 or 2P45- will pick up when relays 2M and IU are simuL s taneously picked up
  • relay IP2D30 or 2P2839 will pick up when relay 3M is picked up
  • relay IPO or 2P9 will pick up when rela AM is picked up.
  • relay lP-l55i5 or 21 45-55 will pick up when relays 2M and All are both picked up
  • relay IP20- 38 or 2P2il3ii will pick up when relays 3M and 4U are simultaneously picked up
  • relay IPO or 2P0 will pick up when relays 5M and 2U are simultaneously picked up.
  • the fluid pressure motor M When lever L is first moved to its pl, p2 or p3 position, the fluid pressure motor M will be supplied with fluid at full line pressure, which I shall assume for purposes of explanation to be 100 pounds per square inch. If the relay lP45-5 :3 or 2P i5-5-5 subsequently picks up, the pressure in motor M will be automaticall reduced to a pressure of between 45 and 55 pounds per square inch, if relay lP20-3fl 0r 2P20-30 picks up, the pressure in motor M will be automatically reduced to a pressure or between 20 and 30 pounds per square inch, and if the relay IPO or 2390 picks up, motor M will be vented to atmosphere to effect the automatic release of the.
  • the p! position of lever L is its off position and is the position to which the lever is moved when it is desired to manually release the retarder.
  • the p4 position of lever L is provided to obtain the full braking force available irrespective of the speed of a car which is being retarded, and when the lever occupies this position, the speed control apparatus is ineffective to control the retarder as will appear presently.
  • a stick relay ISP which is picked up whenever any one of these pressure control relays is picked up
  • a stick relay 281? which is picked up whenever any one of these last mentioned speed control relays is picked up.
  • the stick relays SP and ZSP are provided to prevent the pressure control relays from starting their timing period at the time of their pickup instead of waiting until the track section the occupancy of which caused them to pick up is vacated.
  • the SP relays on each successive speed measurement will maintain energy on any pressure control relay which is then energized until such time as the next track circuit becomes operated, in which event the reversing of the UK relay will release the SP relay which was previously energized and will thereby permit the condenser associated with the energized pressure control relay to function to delay the release of the pressure control relay until a new speed measurement is completed.
  • This terminal board is also provided with a plurality of terminal posts 8
  • This terminal board is further provided with a plurality of terminal posts 93, 94 and 95 which are permanently connected to a wire I02 leading to the movable contact finger 51 of relay UK, with a plurality of terminal posts 96, 91 and 98 which are permanently connected to a wire I03 leading to the movable finger 58 of relay UK, and with a p1urality of terminal posts 99, I00 and IUI which are permanently connected to a wire I04 leading to the movable finger 59 of relay UX.
  • terminal board B when it is desired to effect the operation of one of the P relays at any particular car speed for a particular lever setting, reference is first made to the chart shown in Fig. 3 to determine which combination of contacts of the unit and multiple groups come closest to the desired speed, and the contacts of this combination are then connected in series by means of jumpers, between one of the terminal posts which is permanently connected to the lever contact which is closed for the particular lever setting, and one of the terminal posts which is permanently connected to the wire Hi2, I03 or IE4 leading to the contact of the UK relay which is included in the particular control circuit for the desired P relay.
  • valve V2 is deenergized.
  • Valve VI is energized over a circuit which may be traced from terminal B of the source through contact 25 of lever L, line wire H5, wires H6, H1 and H8, and the winding of valve VI to terminal C.
  • cylinder 4 of motor M is disconnected from the source of fluid pressure and is connected with atmosphere, and the braking bars are held in their inefiective or non-braking positions by the spring Ill.
  • the contact 22--22a of each of the pressure responsive devices 3? is closed, and the contact 22-422?) of each of these devices is open.
  • Valve VI will therefore become deenergized and will disconnect cylinder 4 of motor M from atmosphere, and valve V2 will become energized and will connect cylin-' der 4 with pipe II, thereby admitting fluid to cylinder 4 at full line pressure.
  • the braking bars will therefore immediately move from their ineffective or non-braking positions to their effective or braking positions.
  • track relay ITR When the first axle of the car enters track section IT, track relay ITR will pick up and will cause the W, ISU and IU relays to immediately pick up. The picking up of track relay ITR will also cause the winding 48 of relay UK to become energized, but since the normal contacts of this relay are already closed, the energization of this relay will not cause any operation of the relay contacts. The picking up of the W relay immediately starts the operation of the half-step relays PX and NX, and since relay ISU is then energized, the counting chain starts to function to measure the speed of the car.
  • This circuit includes a resistor I24 and a condenser I25 in series connected in multiple with the resistor I22 and the winding of relay IP45-55 in series.
  • Relay IP4555 and stick relay ISP will therefore pickup and will complete a stick circuit pass ing from terminal B of the source through front contact I21 of relay ISU, wire I28, normal contact 56-5l3a of relay TJX, wire I23, back contact I39 of relay ISP, wire LEE, back contact I32--I32a of relay IPll, wire I33, back contact !34I34a of relay [1 29-30, wire I35, front contact I36 of relay IPli5--55, the resistor I22, the winding of reiay !P45-55, wire I46, and the Winding of relay ISP to terminal C.
  • This stick circuit also includes the condenser I25 and resistor I24 referred to hereinbefore. It should be noted that since this stick circuit includes front contact I21 of relay ISU, back contact I34l34a of relay iPZii-Sfi and back contact I32-i32a of relay lPfi, when relay IP4555 becomes energized under the conditions just described, it will subsequently remain energized until relay IPZU-ZIB or relay lPli picks up or section iT becomes vacated even though the relays 5U and IM of the counting chain which caused it to become energized subsequently release.
  • relay IP45-55 interrupts at its back contact I IU-I Ilia the circuit which was previously closed for valve V2 and completes at its front contact IIOI lllb a circuit for valve VI passing from battery B through contact 29 of lever L, wire Iliil, back contact IIfl-IIIla of relay lPO, back contact IIIl-I Illa of relay 2P0, back contact IIOI Illa of relay IP2U-3ll, back contact lit-I Illa of relay 2P20-30, front contact Hlll lflb of relay IP45-55, wire I40,-contact 22-222) of pressure responsive device P ES-55, wires II! and H8, and the winding of valve V i to terminal C.
  • Valve V2 therefore becomes deenergized and disconnects motor M from the source of fluid pressure, and valve VI becomes energized and vents motor M to atmosphere. Valve VI will continue to vent motor M to atmosphere until the pressure in the cylinder 4 decreases to 55 pounds per square inch, at which time contact 22-221) of pressure responsive device P4555 will open and will deenergize valve VI.
  • Valve V2 will therefore become energized and will connect motor M with the source of fluid pressure until the pressure increases to 45 pounds per square inch at which time contact 22-421) of pressure responsive device P45-55 will open and will deenergize valve V2. It will be seen, therefore, that when relay IP45-55 becomes energized, the fluid in the cylinder 4 of motor M will be reduced to a pressure of between 45 and 55 pounds per square inch, and will be subsequently maintained at this pressure as long as relay [PAS- remains energized.
  • relay IP2030 passing from terminal 13 of the source through contact 26 of lever L, wire 90, terminal post 82, jumper I4I, front contact 15 of relay 2U, jumper I42, front contact I9'of relay 2M, jumper I43, terminal post 96, wire I03, normal contact BE -58d of relay UX, wire I44, resistor I41, the winding of relay IP2030, wires I45, I56 and I 46, and the winding of relay ISP to terminal C.
  • This latter circuit also includes a condenser I48 and a resistor I49 in series connected in multiple with the resistor I 41 and the winding of the relay IMO-30 in series. Relay
  • P20-30 will therefore pick up, and relay ISP will remain picked up. 'When relay IP20--30 picks up, it completes a stick circuit passing from.
  • relay IP2II3!J interrupts at its back contact IIO-I Ilia any circuit which was previously closed for either valve V2 or valve VI, and completes at its front contact IIO-I I 0b another circuit for valve VI passing from. terminal B through contact 29 of lever L, line wire I09, back contact lID-Hlla of relay IPO, back contact IIOlHia of relay 2P0, front contact Nil-JIM) of relay IP2!35. wire I49, contact 22-222) of pressure responsive device P2030, wire H8, and the winding of valve VI to terminal C.
  • Valve V2 if it is not already deenergized when this circuit becomes closed will become de energized, and valve VI will'become energized to thereby again vent fluid from motor M.
  • contact 22--22b of pressure responsive device P2030 will open and will deenergize valve VI, and if the pressure in the cylinder of motor M decreases to 20 pounds per square inch, contact 2222a of pressure responsive device P20-30 will close and will complete another circuit for valve V2 which is similar to the circuit just traced for valve .VI with the exception that this latter circuit includes contact 22-22a of pressure responsive device P20-30, wire II 3, and the winding of valve V2 in place of contact 22-222) of pressure responsive device P20-30, wire H8 and the winding of valve VI. It will be seen, therefore, that when relay IP20-30 becomes energized under the conditions just described the pressure responsive device P2030 will function to reduce the pressure of the fluid in cylinder M to a pressure of between 20 and 30 pounds
  • relay IPO will become energized by virtue of a circuit passing from terminal B of the source through contact 26 of lever L, wire 90, terminal post 83, jumper I50, front contact 11 of relay IU, jumper I5I, front contact 80 of relay 3M, jumper I52, terminal-post 99, wire I04, normal contact 59-59:]. of relay UX, resistor I53, the winding of relay IPO, Wires I56 and I46, and the winding of relay I SP to terminal 0.
  • This latter circuit includes a condenser I54 and a resistor I55 in series connected in multiple with the resistor I53 and the windingof relay IPO in series.
  • Relay [P0 will therefore pick up and since this pick-up circuit includes relay ISP, relay I SP will remain energized.
  • relay IPO becomes energized, it completes a stick circuit passing from terminal B through front contact I21 of relay I SU, wire I28, normal contact 56-56a of relay UX, wire I29, front contact I30 of relay ISP, wire I3I, front contact I32I32b of relay IPIl, resistor I53, the winding of relay IPO, wires I56 and I46, and the winding of vrelay ISP to terminal C.
  • This stick circuit also includes the condenser I54 and the resistor I55 which are included in the pick-up circuit for relay IPD. This stick circuit will maintain relay IPO energized until the leading pair of wheels vacates track section I'I'R.
  • this latter circuit includes reverse;o ontact- 5I5'Ib of relay UX -and-the winding of relay 2P45-'-55 together with the-associated condenser IBI and associated resistors IGI and IE2 inplace-"of the-contact 5'I5Ia-of relay UK and' the -w-inding-of relay IP45-55 together with :the-associated condenser I25 and resistors I24 and I22.
  • This. circuit includes the condenser I and the resistor I24.
  • the circuit'for the relay 2P4 555 is .thecame as that just-traced for the relay IF45 55 except for the difference which will be apparentfrom an inspection of the drawings and from thejoregoingdescription.
  • valve V2 becomes energized and remains energized by virtue of a circuit which passes from battery B through contact 29 of lever L, line wire I09, back contact IIfB-I IBa of relay IPQ, back-contact IIO-I Illa of relay 2P0, back contact IIOIIGa of relay IP2530, back contact IIII--I Illa of relay 2P20-3!i, back contact IIll--I IOa of relay IP4555, back contact HIE- IIUaof relay 2P45-55, wires III, H2 and H3, and thewi-nding of valve'Vz to terminal 0. Since valve :VZremains energized under these conditions the braking bars are held in their braking positions by fluid at full line pressure, and the retarder is effective to exert its maximum braking force during the entire time the car is passing through the retarder.
  • the track circuit lengths as well as the alternating current frequency of the alternator A can be varied depending upon the condition obtaining and the accuracy desired. Ordinarily 60 cycle alternating current would be used since this is the usual commercial frequency available and one that can be accurately controlled in view of its general use for operating electric clocks. If desired an entirely independent source or any desired source of frequency may be used.
  • the number of speeds that may be selected by the operator from the lever L is purely a matter of design.
  • the attached drawings show a high, medium and low speed. This may be amplified to any desired number of speeds that may be needed.
  • the number of pressure reductions is dependent only on the amount of the equipment which is provided. Moreover there is no necessary or essential relationship between the number of speed controls and the number of pressure reductions that may be provided.
  • an additional pressure responsive device Put-80 is provided to provide an additional braking pressure.
  • valve V2 therefore becomes energized and connects pipe I!
  • valve VI which passes from terminal B through contact 20i-20ib of switch MS, contact 23 of lever Li, line Wire 2104, contact 22-22b of pressure responsive device P2 39, an asymmetric unit 206 in its low resistance direction, and the winding I5 of valve VI to terminal C. Valve VI will therefore become energized and will vent fluid from cylinder 4 until the pressure again decreases to 30 pounds per square inch and permits contact. 220--22 b to be open. It will be seen, therefore,
  • valve V2 will then become energized over a circuit which passes from battery B through contact 22-i2!3lb of switch MS, contact 28- of lever LI, line wire 298, contact 22-22a of pressure responsive device PIG-43G, wire 265, and the winding M of valve V2 to terminal C. Under these conditions, fluid will be supplied to cylinder 4 of motor M until the pressure in the cylinder reaches '70 pounds per square inch which is the pressure at which contact 22-22:; of pressure responsive device Pit-80 opens. If the pressure in cylinder 4 now increases to 80 pounds per square inch,
  • valve V I may be traced from battery B through contact Mil-201D of switch contact 28 of lever Ll, line wire 20B, contact 2222b of pressure responsive device Pl8l, asymmetric unit 206' in its low resistance direction, and the winding l4 of valve VI to terminal B. Valve V! will therefore become energized until the pressure in cylinder of motor M again decreases to 89;
  • valve V2 will become energized and will subsequently remain energized by virtue of a circuit which passes from battery B through This latter circuitv contact fill-2M1 of switch MS, contact 29-01 lever LI, line wire209, wire 20.5, and the. windingv of valve V2 to terminal C. It will be apparent, therefore, that under these conditions the braking bars will be held in their braking positions-by fluid at full line pressure.
  • the apparatus immediately and automatically reduces the braking pressure to a value corresponding to the new position of the lever in a manner which will be.
  • lever Ll occupies any one of itsp i p2, 12.3-
  • lever L Associated with lever L is a relay LP which, provides a means for decreasing the general level.
  • the relay LP is provided with a control circuit which passes from: terminal B through contact Zfll-Zflla of manu-- ally operable switch MS, contact 29 oflever L, contact 2 of a manually operable switch MSI,
  • the switch MSI will usually be a push button of the stick type which is built into lever L, and which is arranged to be retained in either of its two positions by suitable detent means.
  • the relay IP has associated therewith a stick relay ISP and is provided with three pick-up circuits one for each of the pl, 322 and p3 positions of lever L.
  • relay IP when lever L occupies its pl position, relay IP will pick up if the speed of a car passing through the retarder becomes less than that at which the relays 5U and IM pick up, namely 11.6 miles per hour.
  • the pickup circuit for relay IP passes from terminal B of the source through contact 200-200a of manually operable switch MS, contact 21 of lever L, wire 9!, terminal post 84, jumper I63, front contact I5 of relay IU, jumper I64, front contact 18 of relay 2M, jumper I65, terminal post 94, resistor 2 I 9 in series with the winding of relay IP connected in multiple with a condenser 22I in series with a resistor 220, and the winding of relay ISP to terminal C.
  • This circuit includes front contact of relay IU in series with front contact I8 of relay 2M, and it follows that when lever L occupies its p2 position, relay ISP will pick up if the speed of a car passing through the retarder becomes less than 9.8 miles per hour.
  • relay IP I in series with the winding of relay IP I connected in multiple with the condenser 22I in series with a resistor 220, and the winding of relay ISP to terminal C.
  • This circuit includes front contact I6 of relay 2U in series with front contact 80 of relay 2M, and it will be seen that when lever L occupies its p3 position, relay IP will become picked up if the speed of the car passing through the retarder becomes less than 9.1 miles per hour.
  • Relay IP is also provided with a plurality of stick circuits each of which includes terminal B of the source, a front contact 2I5 of a different one of the U relays, wire 2H5, back contact 2I'I- 2IIa of relay ISPO, wire 23I, front contact I of relay ISP, front contact 2I8 of relay IP, resistance 2I9 in series with the winding of relay IP connected in multiple with condenser 22! in series with resistor 220, and the winding of relay ISP to terminal C.
  • the front contact 2I5 of at least one of the U relays is always closed when .the unit counting chain is operating and it will be seen, therefore, that when relay IP once picks up it will remain picked up either until the unit chain stops operating, or until relay ISPO picks
  • the relay IPO likewise has associated therewith a stick relay ISPO and is provided with three pick-up circuits one for each of the pl, p2 and p3 positions of lever L. When lever L occupies its pl position, the pick-up circuit for relay IPO passes from terminal B through contact 200200a of manually operable switch MS, contact 26 of lever L, wire 90, terminal post 83,
  • jumper I59 front contact 11 of relay IU, wire I5I, front contact 80 of relay 3M, jumper I52,
  • relay IPO When lever L occupies its p2 position, relay IPO will then become energized if the speed of a car traversing the stretch of track in the drawing decreases below a speed of 5.3 miles per hour by virtue of a circuit which passes from terminal B through contact 200200a of manually operable switch MS, contact 21 of lever L, wire 9
  • relay IPO When lever L occupies its p3 position, relay IPO will then become energized if the speed of a car traversing the stretch of track in the drawing decreases below a speed of 4 miles per hour by virtue of a circuit which passes from terminal B through contact ZOO-400d of manually operable switch MS, contact 28 of lever L, wire 92, terminal post 89, jumper I05, front contact ll of relay 2U, wire I06, front contact 80 of relay 5M, jumper I01, terminal post IOI, resistor 222 in series with the winding of relay IPO connected in multiple with a condenser 224 in series with resistor 223, and the winding of relay I SP0 to terminal 0.
  • Relay IPO is further provided with a plurality of stick circuits each of which passes from terminal B through front contact 2I5 of a different one of the U relays, wire 2I6, front contact 2I'I2I'Ib of relay ISPO, front contact 2
  • relay W has been eliminated, and the energizing circuits for the half-step relays PX and NX previously described in connection with Fig. 1 have been modified to include a front contact 2I2 of relay ISU or a front contact 2I3 of relay 2SU in place of front contact 36 of relay W. It will be apparent, therefore, that when either relay ISU or relay ZSU picks up, the half-step relays PX and NX will immediately start to operate and will continue to operate as long as the relay which initiated the operation remains energized.
  • Relay UK has also been eliminated in Fig. and the initial pick-u circuit for the IU relay which becomes closed when the operation of the unit counting chain is initiated by the picking up of any one of the odd-numbered track relays ITR. 3TB or 5TB. has been modified to include a back contact I3'I3a of relay 2SU in place of the winding of the W relay, and a back contact 255 of relay ISPO and a back contact 226 of relay ISP in place of the winding 48 of the relay UX.
  • this circuit passes from terminal B through back contact 33-331) of track relay ETR, front contact 33--33a of track relay S'I'R, the winding of relay ISU, back contact 13-13:; of relay ZSU, a back contact 44 of each of the relays 2U to EU, inclusive, a back contact 7 and thewinding of relay IU to terminal C.
  • relay ISU since the initial I pick-up circuits for relay IU each include a back contact 225 of relay ISPO anda back contact 226 of relay ISP, the relay ISU or 2SU will not pick up in Fig. 2 unless relays ISP and ISPO are both deenergized. This check insures that the SP relays have released between counting operations and permits the elimination of the alternate series of pressure control relays shown in Fig. 1.
  • the OM relay has been eliminated in Fig. 2, and the stick circuits for the remaining M relays and fcr'the U relayshave been modified to include in addition to the front contact 4-9-4911 of the ISU relay or a front contact 13-131] of the relay ESU depending upon whether the iSU or 2SU relay is then energized, a back contact of the SU relay which is deenergized.
  • the stick circuits for each of the M or U relays includes in addition to the front contact 49-492) of relay ISU, back contact 'l3-13a of relay 2SU, and when relay ZSU is energized, the stick circuits for each of the U or M relays includes in addition to the front contact 13-131) of relay ZSU, back contact 49-69:: of relay lSU. Except for the modification 'just noted, and a modification of the stick a circuit for the relay 3U which I shall describe presently, these stick circuits are otherwise identical with the circuits previously described in connection with Fig. 1.
  • the pick-up circuits for the U and 'M zrelays in Fig. 2 with the exception of the pick-up circuit for relay 3U and the pick-up circuit for the 'IM relay, are identical with the corresponding circuits shownin Fig. 1 exceptffor the fact that front contact 43 of relay W has been ornittedfrom these circuits. This contact has been omitted because the stick circuits for the U relays include the windings of the SU relays which insures proper operation of the U chain.
  • the pick-up circuit for relay 3U when all of the M relays of the multiple chain are deenergized passes from battery B through a normal contact 42 -'42a. of relay NX, front contact 54 of relay 2U,
  • relay IM the pick-up circuit for relay 3U on the next round trip of operation of the unit chain will pass from battery B through contact 4242a of relay NX, front contact 54 of relay 2U, the'winding of relay 3U, wire 232, back contact 63-63a of relays 5M, 4M, 3M and 2M, front contact 63-43311 of relay IM, and the winding of relay MX to terminal C.
  • the pick-up circuit for relay 3U on the next round trip of operation of the unit chain will pass from battery B through contact 4242a of relay NX, front contact 54 of relay 2U, the'winding of relay 3U, wire 232, back contact 63-63a of relays 5M, 4M, 3M and 2M, front contact 63-43311 of relay IM, and the winding of relay MX to terminal C.
  • its front contact will be included in the pick-up circuit which next becomes closed for relay 3U, as will be obvious.
  • the pick-up circuit for relay I'M in Fig. 2 is closed by the picking up of relay EU, and when this circuit becomes closed if an odd-numbered track relay is then picked up, this circuit passes from terminal B through back contact 33'3 3b of each of the track relays in advance of the pickedup track relay, front contact '333'3a of the picked-up track relay, the winding of relay ISU,
  • the pick-up circuit for relay IM when any of the even-numbered track relays ZTR, 4TB. or STR .is then picked up passes from terminal B through back contact -3333b of each track relay in advance of the picked-up track relay, front contact 33-43:]. of thepi-cked-up track relay, the
  • relay ZSU winding of relay 2SU, back'contact 4949a of relay i'SU, front contact 13-131) of relay ZSU, wire a back contact ED of each of the relays 5M, -M, 3M and 2M, normal contact 234 of relay MX, front contact 233 of relay -6U, and the winding of relay IM to -terminalC.
  • the stick circuits for relay 3U in Fig. 2 differ from the stick circuits for relay 3U in Fig. .l in the same manner that the pick-up circuits for relay SU in Fig. 2 differ from the pick-up circuits for relay 3U in Fig. 1. It is believed, therefore, that these stick circuits will be obvious from an inspection of the drawing without further detailed description.
  • the operation of the time measuring means as a whole with the apparatus constructed as shown in Fig. 2a is essentially the same as the operation of the apparatus shown in Fig. la, it being noted that with the apparatus shown in Fig. 2a the NX and PX relays are set into operation by'the picking up of the ISU or .ZSU relay in response to the picking up of a track relay and are subsequently maintained in operation until such track relay releases. With the relays NX and PX in operation, the relays of the unit and multiple chains will function to register the time the relays NX and PX remain in operation to thereby measure the speed of a car traversing the track circuited stretch through the retarder. Since the operation of the time measuring apparatus shown in Fig. 2a is essentially the same as that shown in Fig. la, a detailed description of the operation of this portion of the apparatus is believed to be unnecessary.
  • lever L With the apparatus conditioned to be controlled by the lever L, the operator moves the lever from its 100 to its pl position to slow down a car which is approaching the retarder to the maximum control speed for which the apparatus is designed.
  • the movement of lever L from its 120 to its pl position interrupts the circuit which was previously closed for valve VI and completes one or the other of two circuits for valve V2 depending upon Whether relay LP is then energized or deenergized.
  • valve V2 passes from terminal 38 through contact 29I-2illa of switch MS, contact 29 of lever L, wire 235, back contact 236235a of relay lPil, back contact 231-231a of relay HP, front contact 238-238b of relay LP, wire 239, contact 2222a of pressure responsive device P4555, wire 205, and the Winding H! of valve V2 to terminal C.
  • Valve V2 will therefore become energized and will admit fluid pressure to cylinder 4 of motor M until the pressure in the cy1- inder increases to 45 pounds per square inch, whereupon the pressure responsive device P4555 will function to maintain the pressure in the motor at a pressure of between 45 and 55 pounds per square inch.
  • Valve Vi will therefore become energized and will vent fluid pressure from cylinder 4 of motor M until the pressure decreases to 20 pounds per square inch whereupon pressure responsive device P2ii--3il will then function to maintain the pressure of the fluid in motor M at a pressure of between 2%) and 30 pounds per square inch.
  • valve V2 would then have become energized over a circuit which passes from battery B through contact 20 l-2illa of manually operable switch MS, contact 29 of lever L, wire 235, back contact 23-5236 a of relay IPG, back contact 25'!231a of relay IP, back contact 238238c of relay LP, wire 242, and the winding 14 of valve V2 to terminal C. Under these conditions, none of the pressure responsive devices is included in the control of the valve V2, and it will be apparent therefore that the resultant energizaticn of the valve V2 would cause fluid at full line pressure to be sup plied to motor M.
  • relay IP becomes energized due to the speed of the car decreasing to the proper speed
  • the circuit previously traced for valve V2 would then become interrupted at back contact 231-23154 of relay IP and acircuit would become closed for valve VI at front contact 231-231b of relay IP which latter circuit may be traced from battery B through contact
  • Valve VI will therefore become energized and will vent fluid from cylinder 4 of motor M until the pressure decreases to 45 pounds per square inch at which time the pressure responsive device P45-55 will function to subsequently maintain the pressure of the fluid in cylinder 4 of motor M at the pressure of between 45 and 55 pounds per square inch.
  • valve V will therefore become energized and will vent the fluid which was previously supplied to the motor M to atmosphere to thereby permit the spring 16 to move the braking bars to their non-braking or released positions.
  • relay LP can be picked up or released at the will of the operator by merely operating the switch MSI, and it follows, therefore, that when the lever occupies its pl position, the operator can change the base pressure at which the retarder operates from the full line pressure to half line pressure or vice versa at will.
  • This feature is particularly desirable in yards where some of the cars are heavy cars and other cars are light weight cars, and permits the operator to make the desired selection between the braking force which will be applied to the heavy cars and the braking force which will be applied to the light cars to thereby prevent derailment of the light cars.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
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US424338A 1941-12-24 1941-12-24 Railway braking apparatus Expired - Lifetime US2320802A (en)

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BE477760D BE477760A (enMihai) 1941-12-24
US424338A US2320802A (en) 1941-12-24 1941-12-24 Railway braking apparatus
FR952842D FR952842A (fr) 1941-12-24 1947-09-10 Perfectionnements aux freins de voie

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2690238A (en) * 1951-02-27 1954-09-28 Gen Railway Signal Co Car retarder control system
US2727138A (en) * 1952-04-23 1955-12-13 Westinghouse Air Brake Co Car retarder speed pressure selective control apparatus
US2751492A (en) * 1952-04-23 1956-06-19 Westinghouse Air Brake Co Railway car speed determining and control apparatus
US2763775A (en) * 1952-12-29 1956-09-18 Westinghouse Air Brake Co Alternating current cycle repeater for time measuring means
US2814996A (en) * 1955-06-06 1957-12-03 Gen Railway Signal Co Car retarder control system
US2819682A (en) * 1954-12-08 1958-01-14 Westinghouse Air Brake Co Car retarder speed control apparatus
US3041449A (en) * 1958-11-17 1962-06-26 Acec Automatic braking control system
US3253141A (en) * 1956-04-13 1966-05-24 Gen Signal Corp Control system for railway classification yard

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2690238A (en) * 1951-02-27 1954-09-28 Gen Railway Signal Co Car retarder control system
US2727138A (en) * 1952-04-23 1955-12-13 Westinghouse Air Brake Co Car retarder speed pressure selective control apparatus
US2751492A (en) * 1952-04-23 1956-06-19 Westinghouse Air Brake Co Railway car speed determining and control apparatus
US2763775A (en) * 1952-12-29 1956-09-18 Westinghouse Air Brake Co Alternating current cycle repeater for time measuring means
US2819682A (en) * 1954-12-08 1958-01-14 Westinghouse Air Brake Co Car retarder speed control apparatus
US2814996A (en) * 1955-06-06 1957-12-03 Gen Railway Signal Co Car retarder control system
US3253141A (en) * 1956-04-13 1966-05-24 Gen Signal Corp Control system for railway classification yard
US3041449A (en) * 1958-11-17 1962-06-26 Acec Automatic braking control system

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FR952842A (fr) 1949-11-24
BE477760A (enMihai)

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