US 2235112 A
Description (OCR text may contain errors)
t Patented Mar. 18, 1941 t N UNITED sTATEs PATENT. OFFICE r 12 Claims.
This invention'relates in general to improvements in speed control means for vehicles but .is concerned more particularly with an arrangement for controlling the operation of toy vehicles, for
5 example, and the principal object ofthe linvention is to provide means whereby the speed of a vehicle is controlled in accordance with centrifusal or gravitational forces acting upon the vehicle during its' passage over a path of travel including straight, curved, and graded sections.
A further object of the Vinvention is to provide means for automatically controlling the speed of a vehicle when it enters a curved section of the path of travel or when a down-grade is encountered.
Varrangement for a vehicle in which centrifugal or gravitational forces are eiective to slow up the speed of a vehicle when it enters a curved section 20 of tranci: andis caused to swerve or where it encounters a down-grade, so that derailment of the vehicle is prevented.
A further object of the invention isto provide a`centrifugal or gravitational actuated speed conversally adjustable in order to compensate for various curvatures or elevations of track sections. Anadditional object of the invention is to p`r` vide a novel vehicle speed control arrangement which can readily be applied tov new or existing Vvehicleagdvrlhich is of simple construction, is easy to install and also is economical to manufacture.
'I'he invention in its essence is applicable to the operation of toy electric railroad trains and'consists primarily of a mercury contact tube or switch having a globule of mercury therein, arrangedwithi" the body vof the toy locomotive in such a manner that the movement of the train along a section of track when a curve is encountered, for example, forces the globule of mercury by centrifugal force against the mercury contact electrodes to complete a circuit which is effective to reduce the speed of the vehicle. The mercury tube is arranged to be universally ad- 45 iusted so as to provide for any degree of track y In the operation of toy electric railroad trains it is customary to provide a transformer box having a tapped secondary winding whereby the speed of the electric train may be conveniently regulated manually. In the operation of such anA to train may be speeded up on the straight sections Another object is to provide a speed control trol in which the effective control point is imi- (Cl. 10S-61) of track and slowed down when curves or downgrades are encountered, -insorder thatA no derailments may occurmkordinarilya personoperates the train at the slowest speed possible at which the train can be run without derailment at the curves. This is not altogether satisfactory since a locomotive is not able to pull a large number of carsat the slow speed, and furthermore the. child or person operating' the train derives greater enjoyment therefrom when the trains are operating at a higher speed. When the trains are operating over the track at high speed numerous derailments occur at the curves in the track as is well known, causing considerable damage to the ve-` hicle and track, and necessitating frequent ex- "515 pensive repairs as well as the danger of a child i receiving electrical shocks in replacing the vehicle upon the track. It will be appreciated that the invention is applicable to vehicles whose travel is not confined to a track, but whichtravel freely in any direction indiscriminately.
- In accordance with the foregoing the principal object of the invention is to eliminate the foregoing disadvantag and provide a. speed control arrangement for an electric train in which the speed of the train can be very high on the straightsections of track while upon curvatures or downgrades the speed is greatly reduced automatically without the necessity of manually regulating the speed from the transformer box. Derailment of the train is thereby reduced and the life of the equipment is considerably extended.
Other objects and advantages not particularly pointed out reside in certain novel features of the elements, paris and construction thereof as well as their association and cooperation. 'Ihese will' be apparent and pointed 4out more specifically in the accompanying description'of the invention which, taken together with the drawing discloses a preferred embodiment including several modio cations thereof, of the present invention. In the drawing; l'
Fig. 1 discloses a cross-sectional elevation of a vehicle such as a locomotive showing the inven- 5' 5-'is amodicationof thespeed control 55,
control the speed of the vehicle; while Fig. 6 illustrates a track section arranged for one of the adaptations of the invention.
Referring now particularly to the drawing the reference character 5 discloses a conventional vehicle such as a stream-lined toy electriclocomotive of well known construction formed of stamped The propelling or sheet metal, for example. motive power for the vehicle is indicated generally at 6 and comprises the well known universal A. C.D. C.` series wound electric driving motor supportedand carried between a pair of frame members 1. The supporting members 1 have a `bracket 8 attached thereto at the top through,
which a screw bolt 9 is threaded' for supporting the electric motor within `the locomotive body 5. The driving wheels I and II for thefvehicle are journaled in supporting members 1 and geared to the electric motor 6 at the opposite side of the motor (not shown). A truck I2 carrying a set of wheelsis arranged at the rear end of thelocomotive body and is pivotally supported to a platform `I3 riveted to the sides of the body 5, as shown.`
The electric motor 6 includes the commutator segments I4 upon which `the `motor brushes I5 and I6 are adapted to bear. The brush I5 has a metal tab I1 connected to` it which at the other.
end is clamped by the screw I8 threaded into the metal supporting member 1, whereby the brush I is grounded on the member 1 through the tab and screw I8. The brush I6 is provided with a metal tab I9 for connecting electric wires thereto. Both the brushes I6 and I1 are supported upon an insulated strip 20, suitably secured to the supporting member 1 at each end as shown.
The electric propelling motor 6 is provided with the usual series field winding 2I and a number of armature windings 22, usually 3. A portion of the magnetic field core for the motor 6 is indicated at 23. A variable resistor is provided for regulating the reduced speed atwhich the vehicle is to traverse the `curved or down-grade Asections `of track.` It comprises an appropriate number of turns of a resistance wire 24 wound upon a"curved insulating strip 25, which in turn is secured by screws at each end` tol the supporting member 1. An adjustable wiper arm 26 pivoted at 21 to the member 1 is provided witna projecting tab 23 for manually adjusting the i position` of the arm 26across the resistance 24 Vat any` desired'point. f
The electrical connections for the electric motor 6 extend over wire 29 from one side of the field winding 2l tothe tab I9 and brush I6, while the other side of the field winding 2I extends by'way of lwire 30 to lthe usual collector brush 3l arranged near Athebottom of the vehicle in "contact with the center rail of the track system. The means 4for controlling the speed of the vehicle or locomotive by centrifugal force is shown here inthe form of a mercury switch com' prising a glass tube l32 of `well known construc- 65 tion. The mercury tube 32 is carried upon an adjusting arm 33 arranged within the vehicle and projecting through thejtop thereof. The arm 33 has a pair of spring clips 34 riveted thereon for securely gripping the mercury tube. The mercury tube 32 is provided with-the usual globule of mercury35gwliich'is adapted to movelongitudinally within the tube 32 from one end to the other by either centrifugal or gravitational force.` As shown in Figure 2, the mercury 35 is .normally restingin the left hand portion of the position of the tube. When the mercury moves` over to the right hand end of the tube it establishes an electrical contact` between a pair of electrodes 36. One of the velectrodes 36` is connected by iiexible wire 31 with Lthe resistance coil 24', while the other electrode is connected by exible wire 38 with the brush` tab I9.
With thelever arm 33 in the vertical position as shown in Figure2, the mercury tube 32 isnormally tilted as shown so that the mercury globule 35 rests in the left hand end of the tube or away from the electrodes 36. .As long as the train proceeds over a straight section of track this condition prevails.` However, in the event that the` train enters a section of track which iscurved in` `the left hand direction for example, then the globule of mercury 35 is thrown by centrifugal force across the length of the mercury tube 32` into engagement with the electrodes 36 and an electrical circuit is established therebetween. Should the track section be arranged so that the curvature thereof extends in the right hand direction, the adjusting lever 33 must first be adjusted so that the mercury switch 32 is reversed 180 or change ends from that shown in Figure 2. The foregoing adjustment is provided' for by arranging the adjusting lever 33 to be universallypivoted .as by a bolt 39, whose tension is maintained as by spring washers so that the lever 33 will remain stable in its adjusted position. The
lever pivot 39 and lever 33 are in turn supported electrodes 36 are to be closed.` By turning they lever 33 axially 90. about pivot bolt IIJthe. tube 32 is positioned parallelto the track section and the locomotive so that the globule of mercury in j the tube 32 is effective by gravitational pull to roll along the length of the tubel 32 and establish contact between electrodes 36 when a down-grade section of trackis encountered. By rotating the lever 33 180 from the position shown in Figure 2 the mercury tube 32 is` adjusted to effect its control when. right hand turns are made by the locomotive. It will be likewise apparent with the foregoing adjustments that any desired intermediate position between the aforesaid positions or any other position `in which it is desired to tilt the tube to establish a particularcontrol point,
may be readily accomplished by this universal arrangement.V While `all of the foregoing adjustments are conveniently 'madeby the lever 33 extending through `the top of the locomotive it may be `more convenient to provide a lever arm 42, shown in Figure 2, and attachedito the angular. bracket 40 for adjusting the axial positions of the mercury tube 32.
The wheels I0 and II Aofthe locomotive and the truckV I2 are adapted in the usual manner to ride upon'a pair of rails 43.` These rails 43 serve to carry the feed circuit to the grounded side of the electric motor `6, while the center rail 44 is adapted to be wiped over by the collector 3i car-v ried below the locomotive carriage.
In Figure -3 there is illustrated a circuit diagram depicting in diagrammatic form the various v elements concerned with the invention and the novel circuit arrangement thereof. The usual current feeding transformer 4511s provided, having its primary winding connected by wires 46 and 41 to a source of relative high voltage, such as 110 v. 60 cycles,for example. The secondary winding of transformer 4I are suitably tapped, as shown, at 48 andthe taps are adapted to be engaged at various points by the manual adjustable control arm 49. It is customary in some of the more modern toy electric locomotives to provide means for reversing, the direction ot travel of the locomotive while it is on the track. This may take the form of either an'automatic control or a manual `reversing switch such as that indlcated at 50, which is arranged upon the locomotive 5 in any accessible position,
In the operation of the control arrangement current is normally fed from the tapped transformer secondary winding 48 to the center feed rail, and fromI the manual speed control arm 4! to the outside rails 43. From here the current passes along the outside rails 43 through wheels I and II of the locomotive 5 and from there through the supporting member 1 to the screw I8 and motor brush I5 by way of reversing switch 50.. A branch of this circuit extends from the memberl, pivot 21 and wiper arm 2S, and the resistor winding 24 to the wire 31 and then to one of the electrodes 3S. 'I'he other side of the circuit extends from the center' third rail 44, through collector brush 3l, wire 30, the motor eld winding 2| and the wire 29, by way of reversing switch 50 to the brush I6. A branch of this circuit extends from the tab I9 over wire 38 to the other one of the electrodes 36. 'I'he m0- tor 6 is energized in the well known manner by current passing through the field winding 2l,
'the brushes I5 and I6, commutator I4 and the armature windings 22. This action operates the motor 6 and propels the vehicle or locomotive in.
either a forward or backward direction along the track depending upon the position in which the reversing switch 50 is thrown. The speed of the locomotive, of course, is dependent upon the number of taps 48 of the secondary winding of transformer 45 included in the circuit and the locomotive quickly reachesthe speed at which the arm 49 is set for. 'I'his speed is maintained ,constant as long as a level section of track is traversed by the locomotive. However, as soon as a curved section of track ora down-grade is' encountered, depending on the manner in which the lever arm 3l is adjusted, the mercury globule35 in the tube 32 is immediately thrown by centrifugal force or flows by gravitation along the'tube until it encounters the electrodes 36. The mercury globule 35 remains in this position as long as the curved track or down-grade portion is nbeing traversed by the locomotive. Accordingly, a shunt circuit path is established extending over flexible wires l1 and il from the electrodes 36 through the variable resistor 24 and its wiper arm 26,V in series with the field winding 2| andin parallel with the circuit extending through the motor .l and across the tracks 43 and 44.. Thisshunt circuit around the armature windings 22 isv eifective to greatly reduce current feed tothe windings-22 thereby .quickly eiecting a considerable reduction in the speed of the, locomotive. At the same time the current passing through the field 'winding 2| is proportionally increased which is elective to greatly increase the lmllllletic flux passing through the lcore 24-.and thereby act as a magnetic brake upon the commutator I4. As are. suit the speed of the train is automatically reduced until the locomotive again approaches a straight or level section of track whereupon the globule of mercury 35 moves out of engagement with the electrodes I6 and the aforesaid shunt around the armature windings 22 is removed. The speed of the train is accordingly quickly increased. In order tov properly regulate the amount of the reduced speed at which the train is to negotiate the curves or down-grades the wiper arm 2l can be variably adjusted across the resistor 24 to introduce more or less resistance in the shunt circuit of the motor.
Instead of providing a shunt circuit around the motor armature windings 22 to reduce the speed of the vehicle it is readily conceivable that the same results may be accomplished by connecting the shunt circuit controlled by mercury switch 32, across the field winding 2I. In this arrangement the current through the armature would be greatly increased when the switch 32 operated while the current through the field winding 2| would be considerably reduced and the net result upon the motor 6 would 'be to immediately reduce the speed.
An advantage derived from the arrangement of the invention beside making the standard curves and elevations more-practical is that the number of curves of a typical track layout may lbe greatly increased and the radius of curvature may be considerably shorter than is ai:u present practical, resulting in a saving of trackage` and space and providing for more spectacular and interesting train track layouts.
While the arrangement as Vdisclosed in the drawing is applicable for a train traveling in a tion, shown in Figure 4, is adapted to accomplish this. This figure discloses a curved-shaped mercury tube 5l adustably supported on the adjusting arm 33 and which has a globule,oi mercuryV 59 normally resting in the lower curved portion of the tube 58. Electrodes and 6I are arranged upon opposite ends of the tube 58 andare electrically connected in parallel with each other to the wires 31 and 38. With this l arrangement it is clearly obvious that the cena trifug'al force acting upon the train negotiating either a right or a left hand turn will throw the mercury globule 59 against either electrode B0 or il to effect the reduction in speed of the 1ocomotive. With this arrangement it will be obvio"l likewise that the train can be run either baoitwards or forwards on the track and be slowed downV at the turns. It is conceivable that if desireda pair of` tubes such as 32. illustrated in Figure 2v may be provided, and oppositely disposed or tilted with respect to one another but arranged parallel therewith,- in order to perform the same functions which are adapted to bebrought about by the lmodification shown in Figure 4.
In Figure 5 4there is illustrated a further formV of thefinven Efanfin which instead of providing a mercury tube to control the speed of the train a weighted member andv a set of contacts controlled thereby, performs this control function.
5l `comprises a fiexible leaf spring or `rod 52 'carrying an adjustable weight 53 at its lower end and secured at its other end in a spring pile-up by means of the screws, as shown. A pair of leaf springs 54 and 55 having .contacts on their ends are arranged on one side of the leaf spring 52, while a similar set 56 and 51 are arranged on the opposite side. .This spring arrangement 5| is located within a locomotive and may be suitably supported and arranged forvarious angular adjustments by means of a lever such as 33. When mounted vertically so that the weight 53 hangs downward and with the springs 54 and 55 extending towards the left hand side of the locomotive and springs 56' and 51 on the right hand side, the weight 53 will be swung by centrifugal force either to the right hand side or the left hand side, carrying the leaf spring 52 with it as the train negotiates left or right hand turns. Similarly if the leaf springs 54 and 55 are arranged vertically and facing toward the rear of the locomotive and the leaf springs 56 and 51 towards the front end of the locomotive the spring 52 carrying the weight 53 will |be swung forward as the train encounters down-grades. However, since the weight would also engage either the leaf springs 54 and 55 when moving up an incline or upgrade lit is more practical to provide only a single set of leaf springs, since it. wouldv not be desirable to slow down the speed of the train as it travels up-grade. When the spring set is supported horizontally within the vehicle centrifugal forces are adapted to act upon the weight 53 to effect the speed reducing control as the vehicle encounters a `down-grade. Only one set of springs would be required in this arrangement.
AIn the practical operation of this device when the weight 53 is swung to the left, for example. by the motion of the locomotive entering a curved section of track the leaf spring A54 is rst engaged by spring `52. `This establishes a shunt circuit extending from the rail 43 around the armature windings 22 of the motor 6 over a path extending through the spring leaves 52 and 54 the resistance 24 and 24' through the field winding 2| to the other rail 44. As a result the speed of the locomotive is reduced. Should the curvature of the track be more abrupt or the speed of the train be greater than is ordinarily encountered, i
the weight 53 swings farther to the left until the leaf spring 55 is engaged by leaf spring 54. This completes a shunt circuit around the resistor 24 through leaf springs 54 and 55 resulting in a greatly increased current ow through the resistor 24' so that a greater portion of the current is shunted around the armature winding 22, resulting in "a further reduction in the speed of the locomotive. The leaf springs'56 and 51 are connected in parallel with the leaf springs 54-f and 55 andftherefore perform the same function when the train swerves in the opposite direction and the weight 53 is swung in the right hand direction.
In Figure 6 there is shown a further adaptation ofthe invention/in which a section of track is arranged with the parallel rails 43 bent into a succession of short recurring curves 62. As the trainenters this section of; track at high speed from a straight section it is caused to sway or Weave so that the mercury 35 carried by the locomotiva-is thrown by centrifugal force to the end of the tube into contact with theelectrodes Y 36 and back again. This action is eifective to immediately slow down the speed of the train the same as if the train entered a regular curved section of track. This arrangement would be dsirable, for example, when a train approaches a road crossing or enters a track section where caution is necessary. The same effect may be produced by providing a section of track with a succession of slightly raised portions on opposite sections of the rails, or alternatively a section of straight track may have one of the rails raised used to control contact sets by gravitational or.
centrifugal force is likewise applicable to the Aarrangements pointed out above and needv not be described further.
vIt is apparent from the foregoing that a novel type of vehicle speed control means has been devised in which the speed of a vehicle upon curves or grades is automatically reduced in order to prevent derailment of the vehicle, and that numerous desirable advantages are pro` vided with the arrangement of the invention. Also that the invention i's not limited in its utility to toy electric trains, but is equally as well applicable to large vehicles of any kind.
While various embodiments of the invention have been illustrated and disclosed it will be apparent that other adaptations and arrangements or slight modifications thereof may be devised by those skilled in the art, and it will be understood therefore that the invention is not to be limited by the precise disclosures but only by the extent of the scope of the appended claims.
What is claimed is:
1. In a speed control arrangement `for vehicles,
an electric motor for driving the vehicle, means for' controlling the operation of the motor to the vehicle traverses a straight and level path,
and means controlled by centrifugal and gravitational forces for automatically reducing the motor speed when the vehicle swerves from a straight path or encounters a down-grade.
2.1n a speed control arrangement for vehicles, an electric motor for driving the vehicle,means for controlling the operation of the motor to drive the vehicle at a constant speed as long as -lthe vehicle traverses a straight and level path,
and means lfor 'automatically reducing the speed of the vehicle, said means operated by `centrifugal force when `thevehicle swerves froml c.
straight path, and operated by gravitational force4 when the vehicle encounters a down-grade.
3. In a speed control arrangement for vehicles 1 traversing a track, `an electric motor for driving the vehicle, means for operating the `motor to drive the vehicle at a constant speed; a mercury tube switch4 carried by: the vehicle having a globule of mercury therein normally resting at one end of the .tube as long as the vehicle traverses a straight and level section of track, elecl trodes at the other end ofthe tube connected to said electric motor, means responsive to the i vehicle traversing a curved track section or a down-grade for moving the mercury globule into l 1I contact withsaid electrodes, and a resistance connected tothe motor by the closure of the electrodes for reducing the speed of the vehicle.
`4. In a speed control arrangement for vehicles traversing a track. an electric motor for driving the vehicle, means for operating the motor to drive the vehicle at a constant speed. a mercury tube switch carried upon the vehicle having a globule of mercury therein normally out of engagement with the associated electrodes as long as the vehicle is traversing a straight and level track section, means connecting the elecl trodes and the motor for reducing the speed of the vehicle when the mercury globule is in engagement with the electrodes, and centrifugal and gravitational forces acting upon said mercury globule to cause engagement of the electrodes when the vehicle traverses a curved or downgrade track section.
5. In a speed control arrangement for vehicles traversing a track, an electric motor for driving the vehicle, means for operating the motor to drive the vehicle at a constant speed, a mercury switch arranged to be normally open as long as the vehicle traverses a straight and level track section, and closed when the vehicle traverses a curved track section or a down-grade, means for causing said mercury switch to be closed, and resistance means connected to the motor responsive to the closure of the mercury switch for re ducing the speed of the vehicle.
6. In a speed control arrangementfor vehiclesy traversing a track, an electric motor for driving the vehicle, means for operating the motor to the Amotor to cause the drive the vehicle at a constant speed, a mercury switch carried upon the vehicle and arranged to be open as long as the vehicle traverses a straight and level track section, and closed when the vehicle traverses a curved or down-grade track section, centrifugal and gravitational means acting upon said mercury switch to close the same, means responsive to the clo'sig of the mercury switch for reducing the speed of the vehicle, and means for adjusting the angular position of the mercury'switch upon the'vehicle to position the mercury switch for operation on any degree of track curvature or down-grade.
7. In a speed control arrangement for'vehicles traversing a track, an electric motor for driving the vehicle at a constant speed, a mercury switch carried upon the vehicle and arranged to be open as long as the vehicle traverses a straight and level track section, and closed when the vehicle traverses a curved or down-grade track section, centrifugal and gravitational means acting uponthe mercury switch for closing the same, means responsive to the closure of the mercury switch for reducing the speed of the motor and therefore the vehicle, adjustable means on the vehicle for predetermlning the reduced speed of the vehicle, -and universally adjustable means for angularly adjusting the position of the mercury switch to cause the same to be closed for any degree of track curvature or down-grad 8. In a speed control arrangement forvehicles' traversing a track, an electric motor for driving the vehicle at a constant speed. a mercury switch carried upon the vehicle arranged to be open as long as the vehicle traverses a straight and level section of track, and closed when the vehicle traverses-a curved or downgrade track section, centrifugal and gravitational forces acting upon said mercury switch for causing the closing of the same, means for reversing the operation ot vehicle to traversethe track in the reverse direction, said merclu'y switch effective to be closed as the vehicle encounters curves and down-grades in the said reverse dlrection of travel, means controlled by the closing of the mercury switch for reducing the speed of the motor and therefore the vehicle, and means for adjusting the angular position of said mercury switch with respect to the vehicle, to cause the switch to be closed at any desired degree of track curvature or down-grade.
9. In a speed control arrangement for vehicles I f traversing a track, an electric motorfor driving the vehicle at a constant speed, means for reversing the operation of the motor to cause the vehicle to travel in the reverse direction, a mercury control yswitch carried upon the vehicle and ll comprising a tube having a globule of mercury therein and a pair-of electrodes arranged on each end of the tube, said mercury globule normally resting in the tube between the two pairs of electrodes as long as the vehicle traverses a straight 20 and level track section in either direction of travel, and engaged with one or the other sets of electrodes when the vehicle traverses a right or left hand track curve or encounters a down-grade in either direction of travel, centrifugal and gravi- 25 tational forces acting upon said mercury switch' to cause the engagement of the mercury globule with one of the sets ofI electrodes, and means connecting the pairs of electrodes with the motor for causing the motor to reduce the speed of the 30 vehicle when the globule of mercury engages either set of electrodes.
10. In a speed control arrangement for vehicles traversing a track, an electric motor for driving the vehicle at a constant speed, a control switch $5 carried upon the vehicle and comprising a weighted spring leaf and a second spring arranged in a -contactual relationship therewith, said spring leaves normally out `of engagement with each other as long as the vehicle traverses 4o a straight or level section oi'rtrack and moving in contact with one another when the vehicle encounters Aa curved section of track or a downgrade, centrifugal and gravitational forces acting upon said weighted spring leaf to cause its con- 45 tactual engagement with said other spring leaf, means controlled by the closing of the leaf springs to reduce the speed of the motor and therefore the vehicle, and means for Yadjusting the po's'ition of the control switch upon the ve-` 50 hicle to cause the leaf springs \to be closed for any desired track curvature or down-grade.
ll. In a speed control arrangement for vehicles traversing a track, an electric motor for driving the vehicle at a constant speed, a control switch 55 carried upon the vehicle and comprising 'a weighted flexible member and Va plurality of spring leaves arranged parallel thereto, said spring leaves arranged normally out of contact with each other and the weighted member as 60 long as the vehicle traverses a straight and level section of track, and moving successively in engagement with one another when the vehicle encounters a curved track section or a down-grade, centrifugal and gravitational forces actingupon 5 said weighted member to cause such engagement, and a plurality of resistances connected successively into :the circuit of the electric motor by the engagement of the spring leaves and the weighted member for gradually reducing the .70 speedv of the vehicle, the number of said resistances eective successively being dependent upon the speed with which the vehicle enters the curved track section or down-grade.
12. In a speed control `arrangement for a ve- 75 hicle traversing a track, an electric motor, a cir-V cuit for the motor for driving the vehicle at a constant speed, a control swi-tch carried by thev vehicle, said control sWi-tch being normally open as the vehicle traverses a straight section of track and closing by centrifugal force as the vehicle encounters a curved track section; a resistance connected in shunt of the motor circuit by the closure of the control switch for reducing the 1 y speed of the motor, means for adjusting the position of the control switch upon the vehicle to Ivary the point at which the control switch is 4closed byv the' centrifugal force, and means for adjusting the value of the resistance tovvary the reduced speed of the inotor to Y any desired amount.
ySIDNEY S. PULASKI.