US3214597A

US3214597A - Model train control

Info

Publication number: US3214597A
Application number: US137303A
Authority: US
Inventors: Jr William J Jordan
Original assignee: BUCHLER CORP
Current assignee: BUCHLER CORP
Priority date: 1961-09-11
Filing date: 1961-09-11
Publication date: 1965-10-26
Anticipated expiration: 1982-10-26

Description

0a. 26, 1965 w. J. JORDAN, JR 3,214,597

MODEL TRAIN CONTROL Filed Sept. 11, 1961 N "4 N g5 -i I \O INVENTOR. WILLIAM J. JORDAN JR.

MZJMSM 4211M Afforn us United States Patent 3,214,597 MODEL TRAIN CONTROL William J. Jordan, Jr., Indianapolis, Ind,, assignor to The Buehler Corporation, Indianapolis, Ind., a corporation of Indiana Filed Sept. 11, 1961, Ser. No. 137,303 5 Claims. (Cl. 30743) This invention relates generally to model electric trains and more particularly to an electronic controller for the control of operation, and speed of model electric trains.

In model railroading, great emphasis is placed on the precision of scale of the miniature trains. Many of the trains are of the size designated H.O. gauge. They employ direct current electric motors. Considerable time, effort, and expense are involved in making the model trains, the track layout, surrounding scenery, and all other items associated with the model railroad, precisely to scale. It follows that there is considerable interest in operating the trains at scale speeds, and simulating actual operating conditions, both as to acceleration and deceleration of the model trains.

It has been conventional practice to use controllers for model trains having full wave direct current control voltage sources. In order to obtain very slow motion of the model train during starting thereof, the practice has been to use half-Wave surges in the controller output whereby surging in the model locomotive motor is sulficient to overcome static friction and place a train in motion though at a low speed. The half-Wave energy is obtained normally by using a bridge rectifier, and closing the shorting bar for full-wave operation upon achievement of a desired speed of the train.

The conventional practice has had several serious disadvantages. During the starting of the train, the half- Wave energy has caused rapid heat build-up in the model motors, thus limiting the time during which a train may be gradually accelerated. If, by oversight, the controller is allowed to remain in some position of half-wave application to the motor for an extended period of time, the motor or motors would be ruined by overheating.

A further disadvantage of conventional practice is that after acceleration of the locomotive by the half-wave application, upon closing of the bar in the rectifier bridge, the voltage output to the electric motors practically doubles, causing the train to jump. Thus in addition to excessive heat generation in the model train motors, conventional practice makes precise and realistic control of the trains very difiicult.

It is also conventional practice to use a rheostat in series with the supply to the tracks. Thus as the load on the motors increases during uphill operations, the available voltage to the motors is substantially decreased by the additional drop through the rheostat. Similarly, during downhill operation, the voltage to the motors substantially increases, thus causing extreme speedups of the train during downhill operation. The elfect is to require continuous attention by the model railroad operator during uphill and downhill operation of the trains in order to maintain realistic speeds.

There is a further disadvantage to the conventional practice of using a rheostat in series with the supply to the tracks. It places a severe limitation on the number of motors which can be used simultaneously and operated at maximum speeds. Obviously, the more motors that are in operation, the greater will be the voltage drop in the rheostat, making available less voltage for motor operation.

It is, therefore, a general object of this invention to provide an improved control device for model railroads.

It is a further object of this invention to provide a 3,214,597 Patented Get. 26, 1965 control device for model trains which greatly facilitates the achievement of realism in the operation of the trains.

It is a further object of this invention to provide a control device for model trains whereby a steady and continuous increase of speed of model trains can be obtained from the condition of the train at rest to the condition of the train operating at maximum scale speed.

It is a further object of this invention to provide a control device for model trains whereby the voltage avail able to the train motor is not appreciably influenced by the load thereon.

It is a still further object of this invention to provide a control device having the aforementioned capability and the ability to produce a negligible temperature rise above normally expected temperatures.

It is a still further object of this invention to provide a model train control which does not require either a battery supply for control voltage source or a filtered direct-current supply for the control voltage source.

It is a still further object of this invention to provide a model train control device adapted to employ an unfiltered full-wave direct-current input.

It is a still further object of this invention to provide a model train control device utilizing a half-wave control voltage source. It is a still further object of this invention to provide a model train control device capable of overcoming efiects of dirt on tracks, switch contacts, and the like.

Described brietly, a typical embodiment of this invention includes a control transistor having its emittercollector path in a coupling to a rectified, unfiltered direct-current power supply. The output of the device is obtained from the direct current power supply and includes a pass transistor having its emitter-collector path in series with the output circuit and returned to the ground side of the DC. power supply. Current conduction of the pass transistor is controlled by a coupling from the emitter of the control transistor to the base of the pass transistor.

The control potential for the control transistor is obtained from a potentiometer having its resistance element connected across a source of half-wave energy obtained from a half-wave rectifier, voltage divider combination connected across an A.C. input. An R-C Waveshaping combination is coupled between the potentiometer and the base of the control transistor whereby the ripple from the DC. power supply is modified to produce a pulse output from the emitter of the control transistor. This pulse output is just twice the frequency of the A.C. input to the control voltage source and by application to the base of the pass transistor, provides a pulsed output to the electric train motors at twice the frequency of the A.C. input to the control voltage source. By varying the setting of the potentiometer in the con trol voltage source, the speed of the trains can be controlled. The pulse duration is equal to two-thirds of one-half cycle.

The invention may be better understood from a consideration of the following detailed description when read in accordance with the attached drawing which the single figure shows schematically a typical embodiment of the circuit of this invention.

Referring to the drawing, output terminals 11 and 12 are provided for connection to the tracks of the model railroad layout. The power supply 13, is a non-filtered direct-current source of electrical energy. For the typical model railroad application, an 18 volt source is desirable. Terminal 14 of the source is grounded and terminal 16 thereof provides an input to the circuit of this invention, which may be typically of the form designated by reference numeral 17 and indicative of a full-wave ripple.

A control transistor 18, of the PNP type, is provided in a coupling across the source 13. The emitter of transistor 18 is connected through resistance 19 to the output 16 of the source 13, and the collector of transistor 18 is grounded. Control of this transistor is provided in particularly novel fashion, as will become apparent as th description proceeds.

Input lines

21 and 22 are provided, for coupling a 'source 23 of alternating current electrical energy to the circuit. Typically this source may provide 115 volt, 60 cycle alternating current energy. A half-wave rectifier and voltage divider combination is provided including the diode 24, coupled in series across the

lines

21 and 22, with the resistances 26 and 27. Accordingly, a half-wave voltage is provided between the line 22 and the junction 28 between resistors 26 and 27. By way of example, the values are established to provide a voltage of 13 volts. A potentiometer 31 is provided with a winding 32 connected across the resistor 27. Wiper 33 of potentiometer 31 is coupled through resistor 34 to the base electrode of transistor 18. By the provision of conductor 36 between the input line 16 and the junction 28, a control circuit through transistor 18 is provided, and the setting of potentiometer 31 provides an adjustable control thereof.

A capacitor 37 is coupled between the wiper 33 of potentiometer31, and ground. The combination of capacitor 37 and resistor 34 provides a pulse forming network whereby the voltage waveform of the emitter of transistor 18 taken with respect to input line 16 may be made of the form designated by reference numeral 38.

A pass transistor 41 is provided, having a collector connected to ground and an emitter coupled through the circuit breaker 42 to terminal 43 of the double-pole, double-throw direction reversing switch 44. The other terminal 46 of switch 44 is connected by way of

conductors

47 and 36 directly to the input line 16. With the movable contacts of switch 44 in the position shown, terminal 46 thereof is connected to the output terminal 11, and terminal 43 thereof is connected to the output terminal 12. The base electrode of transistor 41 is coupled through conductor 48 to the emitter electrode of transistor 18. It should be apparent at this point, that transistor 41 is in the load circuit of this invention, and control thereof by control transistor 18, provides the control for the output voltage at terminals 11 and 12. The wave form typically obtained at the output terminals 11 and 12 according to this invention, is designated by reference numeral 49. This voltage is a pulsating DC voltage, having twice the frequency of the full-wave non-filtered direct current input available from source 13. As a typical example, where the input to lines 14 and 16 represents a non-filtered fullwave direct current derived from the 115 volt alternating current source, the output across terminals 11 and 12 would consist of voltage pulses where the pulse rate is 120 per second. Control of the output voltage level is provided by way of potentiometer 31, which therefore has the operating role of the train speed control. Reversal of direction of operation of the trains, may be obtained by merely moving the movable contacts of switch 44 to engagement with the terminals 51 and 52 thereof.

By virtue of the novel construction of the present invention, all of the foregoing objects are achieved. The pulsating voltage wave form across the output terminals 11 and 12 is available at all speeds, though of course the magnitude of the pulses is less as the controlling voltage is lowered by adjustment of potentiometer 31. It should be recognized that the capacity of the circuit can be increased -by addition of transistors in parallel with transistor 41, if desired. For best results, the value of the voltage provided across resistor 27 of the voltage divider, should be slightly less than the voltage input from the power supply 13. For example, where the power supply voltage is 18 volts DC, the voltage across resistor 27 should be no greater than 16 /2 volts.

Forpurposes of example only, the following is a list of components and values which have been successfully used in the practice of this invention.

Perhaps it should be mentioned that NPN transistors can be employed according to this invention as readily as PNP transistors. Moreover, though the invention has been disclosed as particularly beneficial in the operation of model electric train motors, which are usually of the permanent magnet type DC. motor, it is conceivable that this invention may be beneficial in the operation of other DC. motors also.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and Within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

1. A model train control device comprising: I

first input means for direct current electrical energy;

a first electron discharge device having a current flow path therein coupled in series with said input means and having a first resistance means in series therewith, and said discharge device having a control electrode;

second input means for alternating current electrical energy;

a rectifier coupled to said alternating current input means to provide a direct current voltage source;

control circuit means coupling said direct current source to the control electrode of said electron discharge device to provide a source of control voltage for said device; said control circuit means including a pulse forming network coupled to the control electrode of said first device to provide voltage pulses across said first resistance means; I output terminals for a load, one of said terminals being coupled to said first input means;

a second electron discharge device coupled between said first input means and another of said output ter minals, said second device having a control electrode coupled to said first resistance means whereby a pulse voltage is provided at said output terminals and is controllable by said control voltage source.

2. A model train control device comprising:

first input means for direct current electrical energy;

a first transistor having an emitter-collector path coupled in series with a first resistance means and said input means, and said first transistor having a base electrode;

second input means for alternating current electrical energy;

a rectifier coupled to said alternating current input means to provide a direct current voltage source; control circuit means for said first transistor and coupling said direct current voltage source to said first transistor, said control circuit means including said first resistance connected between said source and the emitter of said first transistor, and said control circuit means including adjustable means coupling said direct current voltage source to the base of said first transistor to provide a variable source of control voltage for said transistor;

and said control circuit means including a pulse forming network connected between said adjustable meant: and the base of said first transistor to provide voltage pulses at the emitter of said first transistor;

output terminals for a load, one of said terminals being coupled to said first input means;

a second transistor having an emitter-collector path coupled between said first input means and another of said output terminals, said second transistor having a base electrode coupled to the emitter of said first transistor, whereby a pulse voltage is provided at said output terminals and is controllable by said adjustable means.

3. A model train control device comprising:

first input means for direct current electrical energy having a full-wave ripple;

second input means for alternating current electrical energy of the same frequency as the full-wave ripple at said first input means;

a half-wave rectifier coupled to said alternating current input means to provide a half-wave direct current voltage source;

control circuit means for said transistor and coupling said direct current voltage source to said first transistor, said control circuit means including said first resistance connected between said source and the emitter of said first transistor, and said control circuit means including adjustable means coupling said half-wave source to the base of said first transistor to provide a variable source of control voltage for said transistor;

and said control circuit means including a pulse forming network connected between said adjustable means and the base of said first transistor to provide voltage pulses at the emitter of said first transistor at twice the frequency of the full wave ripple at said first input means;

output terminals to supply model trains, one of said terminals being coupled to said first input means;

a second transistor having an emitter-collector path coupled between said first input means and another of said output terminals, said secondtransistor having a base electrode coupled to the emitter of said first transistor, whereby a pulse voltage having twice the frequency of the full-wave ripple at said first input means is provided at said output terminals and is controllable by said adjustable means to control the speed of model trains.

4. A model train control device comprising:

first input means for ripple-bearing direct current electrical energy;

a first electron discharge device having a load circuit including said input means and having a control electrode;

direct current voltage source coupled in a control circuit with said control electrode to provide a source of control voltage for said electron discharge device;

a pulse forming network in said control circuit and coupled to the control electrode of said electron discharge device to provide voltage pulses in said load circuit;

and a second electron discharge device having a load current conducting path coupled between said first input means and another of said output terminals, said second device having a control electrode coupled in the load circuit of said first electron discharge device, whereby a direct current pulse voltage is provided at said output terminals and is controllable by said control voltage source.

5. A model train control device comprising:

a first energy source providing direct current electrical energy bearing a fullwave ripple;

a first electron discharge device having an energy flow path therein coupled in series with said first source, said first electron discharge device having a control electrode for controlling energy flowing in said path;

a second energy source providing alternating current electrical energy;

a half-wave rectifier coupled to said second energy source to provide a third energy source producing half-wave direct current energy;

coupling means providing a direct current coupling between said third energy source and said control electrode, said coupling means including an adjustable element to change the energy flowing in said path;

aload;

a second electron discharge device having an energy flow path therein coupled in series with said load an d said first energy source to supply direct current energy from said first source to said load through the said flow path of said second electron discharge devico, said second electron discharge device having a cunttrol electrode;

and means coupling the said energy flow path of said, first electron discharge device in a series circuit with the control electrode of said second electron dis charge device to provide a control circuit for saidl second electron discharge device, whereby energy supplied to said load is controllable by said adjust able element.

References Cited by the Examiner UNITED STATES PATENTS Re. 24,678 8/59 Pinckaers 307-88.5 2,837,740 6/58 Riddle 307-88.5 2,864,978 12/58 Frank 307--88.5 2,911,566 11/59 Taylor 3O788.5 3,044,004 7/62 Sicard 307-88.5

LLOYD MCCOLLUM, Primary Examiner.

ILTO 0- H R H I L Q xam ner,

Claims

1. A MODEL TRAIN CONTROL DEVICE COMPRISING: FIRST INPUT MEANS FOR DIRECT CURRENT ELECTRICAL ENERGY; A FIRST ELECTRON DISCHARGE DEVICE HAVING A CURRENT FLOW PATH THEREIN COUPLED IN SERIES WITH SAID INPUT MEANS AND HAVING A FIRST RESISTANCE MEANS IN SERIES THEREWITH, SAID DISCHARGE DEVICE HAVING A CONTROL ELECTRODE; SECOND INPUT MEANS FOR ALTERNATING CURRENT ELECTRICAL ENERGY; A RECTIFIER COUPLED TO SAID ALTERNATING CURRENT INPUT MEANS TO PROVIDE A DIRECT CURRENT VOLTAGE SOURCE; CONTROL CIRCUIT MEANS COUPLING SAID DIRECT CURRENT SOURCE TO THE CONTROL ELECTRODE OF SAID ELECTRON DISCHARGE DEVICE TO PROVIDE A SOURCE OF CONTROL VOLTAGE FOR SAID DEVICE; SAID CONTROL CIRCUIT MEANS INCLUDING A PULSE FORMING NETWORK COUPLED TO THE CONTROL ELECTRODE OF SAID FIRST DEVICE TO PROVIDE VOLTAGE PULSES ACROSS SAID FIRST RESISTANCE MEANS; OUTPUT TERMINALS FOR A LOAD, ONE OF SAID TERMINALS BEING COUPLED TO SAID FIRST INPUT MEANS; A SECOND ELECTRON DISCHARGE DEVICE COUPLED BETWEEN SAID FIRST INPUT MEANS AND ANOTHER OF SAID OUTPUT TERMINALS, SAID SECOND DEVICE HAVING A CONTROL ELECTRODE COUPLED TO SAID FIRST RESISTANCE MEANS WHEREBY A PULSE VOLTAGE IS PROVIDED AT SAID OUTPUT TERMINALS AND IS CONTROLLABLE BY SAID CONTROL VOLTAGE SOURCE.