US2038112A - Railway car retarder control system - Google Patents

Description

RAILWAY CAR RETARDER CONTROL SYSTEM Filed Oct, 20. 1954 2 Sheets-Sheet l 1` ei) x.:

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.- ATTORNEY Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE RAILWAY CAR RETARDER CONTROL SYSTEM Application October 20, 1934, Serial No. 749,230

10 Claims.

This invention relates to railway car retarder systems and more particularly to control means for such car retarders.

In retarders of the type disclosed in Patent No.

1,757,428 granted to W. K. Howe, May 6, 19,30,

the motion of railway cars is retarded by trackway brake shoes applied to opposite vertical surfaces of car wheels, and the degree of retardation is determined by a reversible electric motor under control of an operator, which motor acts on the brake shoes to vary the force biasing the shoes against the car wheels. The control of such actuating motors comprises a plurality of circuits selectively energized by a manual centrol lever, and the selected circuit is automatically de-energized when the motor has operated the retarder mechanism to a position corresponding to that circuit.

In operating such retarder systems, it is intended to preselect the degree of retardation before the entrance of each car, but it often happens that the retarder motor does not complete its full operation when the car enters, and if one of the greater degrees of retardation is selected, it is found that the motor is not able to operate the retarder mechanism to its full stro-ke with the car Wheels between the brake shoes, so that the retarder mechanism cannot automatically de-energize the motor. The operator in such cases considers that the retarder mechanism has fully operated to the selected position, and consequently the greatly increased current caused by the stalled motor continues to flow until the motor is considerably damaged and often burned out.

In view of the above and other considerations, it is an object of the present invention to provide a control means for railway car retarders which automatically detects when a car retarder motor has stalled in an intermediate position, and which automatically de-energizes such a stalled motor before damage can be ldene thereto. Another object of the present invention -is to provide such a protecting means wherein the control of th'e motor can be conveniently reestablished immediately after the stalled motor has been cle-energized.

Other objects, purposes and characteristic features of the present invention will become apparent as the description thereof progresses, during which, references will be made to the accompanying drawings, in which:-

Fig. l shows in a diagrammatic and conventional manner one form of the present .invention.

(Cl. 18S- 162) Fig. 2 shows a. modied form of the present invention also in a diagrammatic conventional manner.

In the accompanying drawings, a car retarder control system has been shown as applied to a car retarder mechanism ef the type fully shown and described in the above referred to Patent No. 1,757,428, granted te W. K. Howe on May 6, 1930, and consequently in order te simplify the present disclosure, the retarder mechanism has not been shown in detail. The retarder brake shoes Ret. are conventionally shown along a railway track indicated by the rails 3, which retarded brake shoes are actuated by a reversible electric motor indicated by an armature A and field F, which motor is at times energized from a suitable source of energy, the opposite potentials of which are merely indicated by the symbols (B+) and (B+).

Theenergizatienand the direction of rotation of the motor is controlled by selectively energizing electro-magnetic relays or contacters I and D, the contacter I being arranged when energized to select a direction of rotation of the motor which will increase the degree of retardation, while the energization of the contacter D is arranged to select the reverse direction of rotation te decrease the degree of retardation. In other words when the contacter I is energized, the motor is energized to produce one direction of rotation over a circuit from (B+), field Winding F, back contact I0 of contacter D, armature A, front Contact il of contacter I to (B-). However when the contacter D is energized, the reverse direction of rotation of the motor is produced by current flowing in the same direction in the field winding F but in the reverse direction in the armature A over a circuit from (B+), eld winding F, back contact I I of contacter I, armature A, front contact Ill of contacter D to (B+).

A plurality of cams C0, C1, C2, C3, and Ct is provided to automatically de-energize the retarder motor through the eontactors I and D in the manner fully shown and described in the above referred to patent to W. K. Howe, or it may be briefly stated that these cams are fixed invariousrelative positions on a common shaft which is rotated by the motor (in the direction ef the arrows for increasing the degree of retardation) in accordance with the operated position of the retarder brake shoes Ret., and each of these cams has a high portion, an intermediate portion and a low portion which operate suitable three-position contacts S0, S1, S2, S3 and S4 respectively so that when the retarder brake shoes Ret., assume a position associated with any one of the cams,

the associated contact assumes a central position. Obviously then the present disclosure illustrates a position of the retarder brake shoes which produces a minimum of retardation thereby positioning the cam CO so that its associated contact S0 is in its intermediate position as shown.

Energy is applied to the various contacts S over individual associated line wires W0, W1, W2, W3, and W4, which wires are selectively energized in accordance with the position of a control lever L (moved in the direction of the arrow to increase the degree of retardation) from a suitable source of energy indicated by a battery E. A common wire CW is provided which forms a plurality of parallel energizing circuits for energizing either the contactor I or the contactor D through the various contacts S to select the degree of retardation of the retarder mechanism in a manner which is obvious from the drawings and will not be traced in detail.

In Fig. 1 of the accompanying drawings, the two line wires W3 and W4 which select the two higher degrees of retardation are provided with series relays SR3 and SR4 respectively, so that when the associated line circuit is energized, these relays are picked up. A suitable time element relay T is also provided which relay may be of any well known type of electro-magnetic device which is arranged to close front contacts immediately upon energization but which will not open its front contacts until a predetermined time has elapsed after its de-energization.

When the lever L is operated to a position selecting the energization of either line wires W3 or W4 the associated series relay will pick up thereby de-energizing the time element relay T, the relay T being normally energized from the source of energy E, through back contact 4 of relay SR3 in series with back contact 5 of relay SR4, and over the common wire CW back to the source of energy E.

The energization of wires W3 or W4 also energizes either the contactor I or D in accordance with the position of contacts S3 or S4 to thereby start operation of the retarder motor. The time element relay T is then adjusted so that the time consumed in opening its front contacts after deenergization is slightly greater than the time required for the retarder motor to operate the mechanism to the selected position. It then follows that in normal operation, one of the cams C3 or C4 open the circuit including line wire W3 or W4 before the time element T opens front contacts 6 and 'I included in series with the wires W3 and W4 respectively.

However, if for some reason the retarder motor stalls so that its energizing circuit is not interrupted by the cams C3 and C4 within the time allotted to the releasing of the time element relay T, the control wires W3 and W4 are opened by contacts 6 and 'I, which de-energizes the selected contactor I or D to remove power from the stalled motor and prevent damage thereto. In order to prevent the series relay SR3 and SR4 from being de-energized when the contacts 6 and I open, stick circuits are provided for these relays which include respective front contacts 8 and 9 and current limiting resistors CR3 and CR4 respectively. These stick circuits then function in a manner obvious from the drawings to provide a local energizing circuit for the respective relays SR3 and SR4 after being originally energized over the line circuits.

When the lever L is moved to a new position, the relay SR3 or SR4 is de-energized which again energizes the timing relay T which picks up to close the line circuits including wires W3 and W4. If this new position of the lever L energizes wires W3 or W4, the corresponding one of the relays SR3 or SR4 is again picked up thus again de-energizing relay T which opens its contacts 6 and 1 after the predetermined time has elapsed, thereby checking the completion of the retarder operation in the same manner as just described. The contact shown, having no wire connected to it, to which the lever L can be moved, is an emergency contact and merely indicates that lever L can be moved away from an operative position, without necessarily positioning it at a different control point, and as brought out below, is useful for resetting the system.

In the modied form of the present invention shown in Fig. 2, one series relay SR only is ernployed in the common line wire CW, which relay SR controls the time element device T by its contact I'I, and the device T in this form operates contacts I3, I4, I5 and I6 included in the line wires W1, W2, W3, and W4 respectively. When the lever L in Fig. 2 is moved from its position shown to energize any one of the wires W1, W2, W3, or W4, the current flowing in the common wire CW picks up relay SR thereby de-energizing the timing device T to initiate a time interval which is matched against the time of operation of the retarder mechanism in the same manner as in Fig. 1.

In other words, if the retarder Ret. stalls the operating motor, the timing device T opens the circuits including wires W1, W3, W3 and W4 at contacts I3, I4, I5 and I6 respectively after the expiration of the normal operating time of the retarder, thus de-energizing the selected contactor I or D which removes energy from the motor and prevents damage thereto.

In order to prevent the relay SR from restoring the timing device after the line circuits have been thus interrupted, stick contacts I8, I9, 20 and 2l in series with current limiting resistors R1, R2, R3 and R4 are provided in multiple with the contacts I3, I4, I5 and I6 respectively of the timing device T. The resistors R are of such a value that when these stick circuits are closed by the picking up of relay SR, suilicient current flows in the line circuits to retain relay SR up but which current is not sulicient to retain the more ruggedly constructed contactors I and D picked up.

When the lever Lin Fig. 2 is positioned to select the energization of one of the wires W1, W2, W3 or W4 and the cams C have interrupted this energizing circuit before the timing device T has dropped, the relay SR of course is de-energized thereby resetting the timing device T (by re-energizing it) and preventing the contacts I3, I4, I5 and I6 from opening, and this permits the lever L to be subsequently moved to a position energizing any other one of the wires W1, W2, W3 or W4 and the timing device T again functions in the same manner. However if in the above case, the timing device T has opened the line circuits before the cams C due to a failure of the retarder mechanism to fully respond, the relay SR is maintained picked up and through its stick circuits prevents a subsequent movement of the lever L from effectively energizing the contactors I and D over any other one of the wires W1, W2, W3 or W4, and in order to select a retarder position corresponding to one of these wires, the lever L must first be moved to a position to drop relay SR and hence pick up T, such as the circuit including wire W0, in order to thus de-energize SR, at once if S cuit, timing means operable upon initiation to be open, or if S0 be not open, to cause operation of the motor to open the retarder thus to permit cam C0 to open S0 and hence to remove current from the common line Wire CW and thereby deenergize relay SR and reset the timing device T. Movement of the lever L to the uppermost contact (the one having no wire connected to it) also will effect resetting, and is useful in the event the motor, for any reason, as for example because of frozen bearings should become incapable of opening the retarder.

A control means for railway car retarders has thus been provided in which the normal time of operation of the retarder mechanism is matched against the operation of a timing device whereby a stalled condition of the retarder mechanism is detected and the power removed therefrom before damage can be done thereto. Other features oi' the system includes the provision of such an automatic protecting means wherein the operator can conveniently reestablish the control circuits at the control point with a minimum of delay after the operation of the protecting means.

The above rather specific description of the form of the present invention is given solely by the way of example, and is not intended, in any manner whatsoever, in a limiting sense. It is also to be understood that various modifications, adaptations and alterations may be applied to meet the requirements of practice Without in any manner departing from the spirit or scope of the present invention, except as limited by the appended claims.

Having thus described my invention, what I claim isz- 1. In a car retarder system for railroads, trackway braking means operated by an electric motor, a control circuit for the motor, cut-out means operated by the braking means to open the control circuit at a predetermined operated position of the braking means, a time-element circuit breaker controlling the control circuit, and means initiating operation of the circuit breaker upon energization of the control circuit, said circuit breaker having an o-perating time slightly exceeding the time normally consumed by the motor in operating the braking means to said predetermined position.

2. In a car retarder system, trackway braking means operated by an electric motor, a control circuit for effecting operation of the motor, cutout means operated by the braking means in a manner to open the control circuit at a predetermined operated position of the braking means, a relay in series with the control circuit, a timeelement circuit breaker initiated by energization of the relay and operable to open the control circuit after a period of time exceeding the time normally consumed by the motor in operating the braking means to said predetermined position, and a stick circuit maintaining the series relay energized after the control circuit is opened by the circuit breaker.

3, In a car retarder system, trackway braking means operated by an electric motor, a plurality of control circuits each effecting operation of the motor, a remote manually operable lever for selectively energizing the control circuits, a cut-out device controlling the control circuits, whereby the braking means is operated by the electric motor until the braking means assumes a position corresponding to that of the control circuit selected by the manually operable lever after which the cut-out device opens the selected control ciropen certain of said plurality of control circuits after a time interval exceeding the time normally required for the motor to operate the braking means to a position corresponding to that of the lever, and means initiating operation of the timing means upon energization of one of the control circuits.

4. In a car retarder system, trackway braking means operated by an electric motor, a plurality of control circuits each effecting operation of the motor, a remote manually operable lever for selectively energizing the control circuits, a cutout device controlling the control circuits, whereby the braking means is moved by the electric motor untily the braking means assumes a position corresponding to that of the control circuit selected by the manually operable lever after Which the cut-out device opens the selected control circuit, timing means operable upon initiation to open certain of said plurality of control circuits after a time interval exceeding the time normally required for the motor to operate the braking means to a position corresponding to that of the lever, means initiating operation of the timing device upon energization of one of the control circuits, and means maintaining the timing means in a condition wherein the control circuits are held open until the position of the control lever is manually changed.

5. In a car retarder system, trackway braking means, a plurality of control circuits arranged to effect operation of the braking means to various associated positions, cut-out means arranged to open each of the control circuits when the braking means assumes a position corresponding thereto, relays in series with the control circuits associated with the more extreme positions of the braking means, a timing circuit breaker controlled by the relays and controlling the circuits including the relays whereby to insure that such circuits are opened a predetermined time after energization thereof, and stick circuits maintaining the existing condition of the relays after the associated circuits are opened by the circuit breaker.

6. In a car retarder system, trackway braking means, a plurality of control circuits arranged to eect operation of the braking means, cut-out means arranged to open each of the control circuits when the braking means assumes a position corresponding thereto, a relay controlled by all of the control circuits, a timing circuit breaker controlled by the relay and controlling the control circuits associated with the more extreme positions of the braking means whereby to open such circuits only when an abnormal condition prevents operation of the cut-out means, and stick circuits including portions of the control circuits controlled by the circuit breaker and maintaining the existing condition oi the relay after operation of the circuit breaker and until operation of the cut-out means.

7. In a car retarder system for railroads, trackway braking means, an electric motor for actuating the braking means, a plurality of line circuits arranged to energize the motor in accordance withfenergy selectively applied thereto at a remote location, contact means operated by the braking means to open each line circuit when the position of the braking means corresponds thereto, and a time-element circuit breaker started by the energization of a line circuit and operable to open the same line circuit if said contact means does not open the same line circuit within a normal allotted period of time.

8. In a car retarder system of the type wherein a trackway braking means is positioned in accordance with manually selected energization of a plurality of control circuits and wherein the selected control circuit is automatically de-energized when the braking means assumes a position corresponding thereto, the combination of relay means responsive to the energization of the control circuits, circuit breaking means controlled by the relay means and opening certain of the control circuits after the control circuits have been energized for a predetermined time, and stick means arranged to maintain the relay energized until the selected energization of a dierent circuit.

9. In a car retarder of the track brake type, in combination, motive means for adjusting the position of the retarder, normal control means for the motive means, and emergency control means for the motive means, effective upon failure of the normal control means to properly function.

10. In a car retarder of the track brake type, in combination, motive means for adjusting the position of the retarder, normal control means for the motive means to stop operation of the control means after a predetermined extent of operation, and emergency control means for the motive means, effective a predetermined time after initiation of the control means, to cut the control means out of operation.

WINTHROP K. HOWE.

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