US2872879A - Model railway system - Google Patents

Description

l Feb. 10, 1959 R.1 .vlER| 1NG MODEL RAILWAY SYSTEM Filed -May 10. 1954 -ZzrEz-i :r

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United States Patent O MODEL RAILWAY SYSTEM Robert L. Vierling, Chicago, Ill.

Application May 10, 1954, Serial No. 428,412

2 Claims. ((11.1104-149) This invention relates to model railroad systems and pertains particularly to means for simultaneously and independently controlling the speed and direction of a plurality of model railroad locomotives.

Accordingly, one principal object of the invention is to provide a model railroad system having improved means for operating a plurality of locomotives simultaneously and independently of one another.

Another object is to provide an improved control system for independently reversing the directions of operation and controlling the speed of a plurality of model railroad locomotives or other power operated cars or devices.

Further objects and advantages of the invention will appear from the following description, taken with the accompanying drawing, in which: Figure 1 is a diagrammatic representation of an illustrative embodiment of the invention in the form of an exemplary model railroadsystem; and

Fig. 2 is a diagrammatic representation of a modified circuit arrangement which may be embodied in the system of Fig. l.

Considered in greater detail, Fig. l of the drawing illustrates a model railroad system 10 including the usual rail means 11 serving to support model railroad cars and locomotives and to conduct energizing current to the locomotives and other power operated devices. As illustrated, the rail means 11 include a pair of wheel supporting guide rails 12, serving as return conductors, and a central third rail 14 providing a supply conductor. However, it will be understood that any suitable or desired rail arrangement may be employed.

The exemplary railroad system 10 includes two locomotives 15 and 16 which may be controlled independently of each other by means soon to be described. Each of the locomotives 15 and 16 is supported by rail engaging wheels 1S which also serve to make electrical ,contacts with the return conductor rails 12. A shoe or brush 19 is mounted on each locomotive to engage the supply rail 14.

Power for operating the locomotives 1S and 16 is provided by respective electrical power units 21 and 22 connected to the rails 12 and 14. In order that the locomotives l and 16 may be controlled entirely independently of each other, the power unit 21 is arranged to deliver direct current, while the power unit 22 provides alternating current.

commercial frequency. The transformer 24 also includes a secondary Winding 2S having end terminals 29 and 30 and a plurality of intermediate taps 31. A slider or contactor32 is arranged to engage any of the terminals 29, 30, and 31 so as to vary the output voltage .derived from the 41 and 42. The reversing switch 40 includes a pair of 1 switch arms 44 and 45 which are operable in the usual manner by means of a toggle lever 46 connected to the switch arms through an overcenter spring 47. The provision of the snap type reversing switch insures fast action. lt will be understood that any other type of rapidly acting reversing switch may be employed.

The illustrated alternating current power unit 22 includes a transformer 50 having a primary winding 51 connected to the alternating current supply lines 26 and 27. The transformer 50 includes a secondary winding 52 having end terminals 53 and 54 and a plurality of intermediate taps 55. A contactor 56 is arranged to engage any of the terminals S3, 54, and 55. One end terminal 53 and the contactor 56 are connected to output leads 58 and 59. However, to provide for directional control over the alternating current locomotive 16, a current interrupting switch 6i) is connected between the transformer 50 and the leads 58 and 59. This switch 60 may comprise a movable contact 61, operable by a push button 62, and normally engaging a contact 64. The contacts 61 and 64 are connected in series with one output lead, in this case the output lead S8. It will be understood that the supply of alternating current to the leads 58 and 59 may be interrupted by pushing the button 62 and thereby opening the contacts 61 and 64. In order that direct current may be bypassed around the alternating current power unit 22 when the contacts 61 and 64 are opened, the contact 61 is arranged to engage a contact 65 when it is moved away from the contact 64. The contact 65 is connected to the other output lead 59. Accordingly, the contacts 61 and 65 provide a conductive path between the output leads 58 vand 59 when the push button 62 is depressed to interrupt me supply of alternating current.

The direct and alternating current power units 21 and 22 may be connected to the rails 12 and 14 in various ways, but in this instance the power units are simply connected in series across the rails. This may be done, for example, by connecting the output leads 42 and 58 together and then connecting the output leads 41 and 59 to the rails 12 and 14.

In order that the locomotive 15 may operate only on direct current, it is provided with a drive motor having a commutator type armature 71 and a permanent magnet field 72. The armature 71 is electrically connected between the wheels 1S and the shoe 19 of the locomotive 15, and is mechanically coupled to the Wheels 18. Due 'to the provision of the permanent magnet field 72, the motor '7d will operate only on direct current and will operate in opposite directions depending upon the polarity of the direct current. Another possible arrangement to secure this result would be to provide a wound field energized through a full wave rectifier. The reactance of the armature 71 preferably is made as great as possible to minimize the flow of alternating current through the armature, since such allow of current would tend to lheat the armature.

The alternating current locomotive 16 is provided with a driving motor 74 or any suitable type operable on alternating current. The illustrated motor 74 comprises a wound eld 75 adapted to be connected in series with a commutator Vtype armature 76 which is mechanically coupled to the wheels 18 of the locomotive 16. In order that the motor 74 may operate on alternating current only, a capacitor '78 is arranged 'in a series circuit with the motor across the wheels 1S and shoe 1'9 which engage the energizing rails 12 and 14.

To control the direction of operation ot' the driving motor 74, the locomotive `16 is equipped with a suitable control device Sil, which may, for example, be operable by interruption and subsequent re-establishrnent of the alternating current -energization of the rails 12 and 14. The illustrated control device 89 is in the form of a relay switch adapted to reverse the connections to the field 7S of 'the motor 74. it will be understood .that the same result Lmight be achieved by reversing the connections to the armature '.76A The specific illustrated relay switch mechanism 89 comprises a switch ring d1 having a pair of diametrically opposite conductor segments 32 and 83 separated by insulating segments 84 and 85. Pour equally spaced brushes S7, 88, 89, and 90 engage the switch ring l8l. Two opposite brushes SS and 9) are connected to the field 7S. The other two brushes 37 and e9 are connected to the leads 92 and 93 extending respectively to the capacitor 37 land the armature 76. Accordingly, the brushes l37 and 89 are in the series circuit energized from the rails 12 and 14;

It will be evident that rotating the ring S1 through steps of 90 degrees will reverse the connections to the eld 75 and thus reverse the direction of operation of the motor74. Such rotation of the switch ring is effected by means of a ratchet wheel 95 mechanically coupled to the ring. A pawl 96, `operable by a solenoid 97, is provided to advancethe .ratchet wheel 95 through steps of 90 degrees. The'pawl 96 is advanced by energization of the solenoid 97 vand is returned by the biasing yaction of a spring $8, when the solenoid is die-energized. A lead 99 -connects one end of the solenoid to the shoe 19. The other end of the solenoid is connected by means of a lead 109 to the capacitor 7S and thence to the wheels 18. films, the capacitor '78 is in series with the solenoid 97 to prevent direct current from energizing the solenoid. It will be evident that each cycle of de-energization and re-energization of the solenoid is eiective to advance the switch ring 89 through 90 degrees and thus reverse the direction of operation `of the motor 74.

In operation, the direct current locomotive is energized by adjusting the contactor 32 of the direct current power unit to provide a suitable direct current voltage between the rails 12 and 14. The alternating current from the transformer 24 is rectified by the full wave rectiiiier 34 and is conducted to the output leads 41 and 42 by the reversing switch 40. The direction of operation of the direct current locomotive 15 may be reversed by operating the reversing switch 40. To stop the locomotive 15, the contactor 32 is moved into engagement with the end terminal 29, which has the elect of reducingr the energizing voltage to zero.

The alternating current locomotive 16 isoperated by the alternating current power unit 22. To adjust the speed of the locomotive 16, the contactor 56 is shifted along the taps 55 on the transformer 5G. lf the contactor 56 is engaged with the .end terminal 53, no alternating voltage will be produced by the power unit 22, and the locomotive 16 will stop. However, the conductive continuity between the output leads 58 and S9 of the power unit 22 will be maintained. Accordingly, the `operation of the direct current locomotive 15 will not be affected. f

It should be noted that the alternating current for energizing the locomotive 16 is bypassed around the direct current power unit 21 by the capacitor 3S. It has been found that this capacitor prevents rectification of the alternating current by the rectilier 34. If the capacitor 38 `is removed from the circuit or is made insuciently large, the resulting rectcation of the alternating curl rent will cause the, alternating current power unit 22l to operate the direct current locomotive 15. The actual value of the capacitor 38 may be varied widely. However, in one actual installation, a capacitor bank having a total value of 3,000 microfarads was successfully employed.

To reverse the direction of operation of the locomotive 16, the push button 62 is depressed so as to break the contacts 61 and 64 and thus open the alternating current circuit from the transformer 5t! to the output leads 53 and 59. Depressing the push'button 62 also closes the contacts 61 and 65 and thereby connects the output leads 58 and 59 ogether so as to bypass the direct current from the power unit 21 around the alternating current power unit 22 and thus prevent interruption of the cnergization of the direct current locomotive 15.

In the arrangement of Fig. l, the series circuit connecting the alternating current power unit 22 to the rails 12 and 14 isV momentarily interrupted when the reversing switch 40 is operated. For this reason the reversing switch 4l) is made fast acting, while the solenoid actuated stepping relay is made slow acting. in this way, operation of the reversing switch 4d does not affect the relay and, hence, does not reverse the direction of operation of the alternating current locomotive 16.

ln the arrangement of Fig. l, the reversing switch 40 is connected between the bypass capacitor 38 and the output leads 41 and 42. This is done to minimize surge currents through the capacitor. it will be understood that the capacitor 3S becomes charged from the direct current power unit 21. However, the charge in the capacitor 38 is not atfected by the operation of the reversing switch 40 in Fig. 1 because the switch is connected betweenrthe capacitor and the output leads 41 and 42, rather than between the rectier 34 and the capacitor. With this arrangement, as already indicated, the reversing switch 40 should be made fast acting and the stepping relay 80 slow acting. v

Fig. 2 illustrates a modified arrangement which dispenses with any need for maintaining a relationship vbetween the speed of operation of the reversing switch and that of the stepping relay 80. A conventional reversing switch 40a, which may be of any desired construction, is connected between the leads 3'6 and 37 and a bypass capacitor 38a, which is analogous to the capacitor 38 of Fig. l. The capacitor 38a is thus connected directly across the output leads 41 and 42. Accordingly, the alternating current from the power unit 22 is bypassed around the direct current power unit 21 even when an open circuit condition exists in the reversing switch 40a. However, the charge on the capacitor 38a is reversed wheneverV the reversing switch 40a is operated. Such reversals can be accommodated if the capacitor 38a is of a suitable type. v

Other locomotives may be independently controlled by connecting high frequency alternating current power units in the series circuit across the rails 12 and 14, either in addition to or vas substitutes for the power units 21 and 22. Terminals 102'and 103 are provided for this purpose in the present embodiment. A lead 104 is normally connected across these terminals. Such additional power uni-ts .may be arranged to provide alternating currents at progressively 'higher frequencies, such as 500 and 5000 cycles, for example. Likewise, the additional locomotives may be arranged to operate only ou such high frequency alternating currents. This may be accomplished, for example, by connecting a blocking capacitor in series with each of the higher frequency'locomotives. This capacitor should have a value such that its impedance is low at the higher frequency but high at the lower frequencies. vWhen high frequency power units are employed, each of the lower frequency power units should be provided with a bypass capacitor connected across its output terminals to bypass the high frequency currents around the lower `frequency'unit. Thevalue of the capacitor should be such that its impedance is relatively high at the low frequency but relatively low at the high frequency.

Various other modifications, equivalents, and alternative constructions may be employed without departing from the true spirit and scope of the present invention, as set forth in the foregoing specification and accompanying drawing, and as dened in the following appended claims.

I claim:

l. In a model railroad system, the combination comprising rail means including a pair of conductor rails, a first locomotive movable along said rail means and having reversible traction motor means connected to said rails and operable by direct current only for propelling said locomotive, a second locomotive movable along said rail means and having second traction motor means connected to said rails and operable by alternating current only for propelling said second locomotive, said second locomotive also including a capacitor connected in series with said second motor means to block direct current therefrom, said second locomotive also having means connected to said rails and operable by de-energization and subsequent re-energization of said rails with alternating current to reverse the direction of operation of said second motor means, direct current supply means and alternating current supply means connected in series across said rails, a capacitor shunted across said direct current supply means for bypassing alternating current, said direct current supply means including a reversing switch for reversing the polarity of the direct current output thereof and thereby reversing the direction of travel of said rst locomotive, said alternating current supply means including interrupting switch means for controlling the direction of operation of said second locomotive, said alternating current supply means including means for maintaining conductive continuity thereacross and thereby bypassing direct current therearound when said interrupting switch means is operated.

2. In a model railroad system, the combination comprising rail means including a pair of conductor rails, a rst locomotive movable along said rail means and having traction motor means operable by direct current only for propelling said locomotive, said motor means having a permanent magnet eld and a commutator type armature connected to said rails, a second locomotive movable along said rail means and having second traction motor means operable by alternating current only for propelling said second locomotive, said second motor means having a commutator type armature and a wound field connected in series between said rails, said second motor means also including a capacitor connected in series with said armature and said tield to block direct current from said second motor means, said second locomotive also having relay switch means connected to said rails and operable by de-energization and subsequent reenergization of said rails with alternating current to reverse the direction of operation of said second motor means, direct current supply means and alternating current supply means connected in series across said rails, a capacitor shunted across said direct current supply means for bypassing alternating current, said direct current supply means including a reversing switch for reversing the polarity of the direct current output thereof and thereby reversing the direction of travel of said lirst locomotive, said alternating current supply means including an interrupting switch means connected in series therewith for operating said relay switch means on said second locomotive and thereby controlling the direction of operation thereof, said interrupting switch means including means for maintaining conductive continuity across said alternating current supply means and thereby bypassing direct current around said alternating current supply means when said interrupting switch means is open.

References Cited in the file of this patent UNITED STATES PATENTS 484,549 Witt Oct. 18, 1892 503,321 Hunter Aug. 15, 1893 793,033 Kitsee June 20, 1905 1,569,233 Morton Jan. 12, 1926 1,778,465 Ozanne Oct. 14, 1930 1,897,749 Bonanno Feb. 14, 1933 2,155,343 Bonanno Apr. 18, 1939 2,172,468 Giaimo Sept. 12, 1939 2,521,240 Milne Sept. 5, 1950

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