US2140640A - Acceleration and deceleration controller - Google Patents

Description

Dec. 20, 1938. J. c. M cuNE 2,140,640

ACCELERATION AND DECELERATION CONTROLLER l FiledFeb. 24, 1934 K I INVENTOR O JOSEPH C.M0OUNE BY 6X64? ATTORN Patented Dec. 20, 1938 UNITED STATES 1mm OFFICE ACCELERATION AND DECEIERATION CONTROLLER Application February 24, 1934, Eierial Noa $112,732

8 Claims.

This vention relates to acceleration and deceleretion controllers, and more particularly to means for controlling the acceleration and deceleration of railway vehicles and trains.

in the operation of modern traction and interurbsn railway systems, the time required to accelerate and decelerate the vehicle or train becomes an important factor in maintaining last schedules. In order to minimize the time re- 10' quired for acceleration and deceleration, and to make starts and stops more uniformly, ,it-has been proposed to provide means for automati celly controlling the acceleration and deceleration, so that such will not be dependent upon the skill of the operator.

It is a principal object of my invention to provide means for controlling-both the acceleration end deceleration of a railway vehicle or train, which means will operate to control the maximum rate of acceleration or deceleration so as to prevent sliding oi the wheels.

Another object of my invention is to provide an apparatus having a member responsive to changes in the rate of speed and providing for a. desired maximum rate of acceleration and o. desired maximum rate of deceleration, regardless of whether or not the vehicle or train is lightly loaded or heavily loaded.

Further objects of my invention will be apparent from the following description, which is taken in connection with the attached drawing illustrating one embodiment thereof, wherein the single figure there shown illustrates in diagrammatic form an inertia. operated device and connected apparatus for controlling both the acceleration and deceleration of a vehicle or train.

As shown, the inertia operated device comprises s. pendulum I0 adapted to swing about a pivot I 2 and having a body portion l4 carrying contacts l6 and i8 insulated therefrom. The contact I6 is adapted to engage resilient and yieldable, stationery contacts 20 and 22, while the contact 18 is adapted to engage similar contacts 24 and 26.

The contacts i8, 20 and 22 are adapted to control operation of the acceleration control apparatus, which I have shown in connection with a single vehicle motor having an armature Z8 and a. series field 30, although it will be readily apparent that any other number of motors may be used. The motor field and armature are adapted to receive current from a source through a. trolley 32 end a ground connection 34. The flow of current to the motor is regulated by a controller having a, resistance unit 3! adapted to be varied by s rotatable dim 3B driven'by a motor 40 through a worm end worm gear 42.

The motor til is preferably of the constent speed type, and may be energized from any suitable source through conductors it. For controlling operation of the motor 48 there is provided a relay 46 having contacts 48 connected in the circuit to the motor. The contacts 48 remain closed so long as relay 46 is either deenergized or insufiiciently energized to open the. contacts.

The relay 46 is connected across a resistance device 50 in series with the vehicle motor and is, therefore, adapted to be energized in accordance with the flow of current to the motor.

Another resistance device 52 is connected in series with the relay 4B, and has one terminal thereof connected to the aforementioned contact 20 and the other terminal thereof connected to the aforementioned contact 22.

It will thus be seen that when the pendulum I0 swings to the left, contact It will engage and bridge the two contacts 20 and 22, and thereby shunt the resistance device 52. The purpose of this will more fully hereinafter appear.

The contacts i8, 24 and 26 are, as is shown, adapted to control apparatus ior controlling operation of the brakes,

For purposes of illustration, I have shown this apparatus as comprising a. brake controlling valve device 54, and a brake valve device 56, for controlling the supply of fluid under pressure to a brake cylinder 58.

The brake valve controlling device 54 comprises a supply magnet valve section 6B,-a. release magnet valve section 82, an inshot valve section 84, and asofety valve device 86 secured to the inshot valve section t4.

The supply magnet valve section 68 comprises ceasing provided with a valve chamber 68, having constant communication withthe brake cylinder 58 by passage I0 and pipe", and having disposed therein e, double beet valve l4 secured to a. valve stem it. lfhe double beet valve 14 is urged toward on. upper seat it by a spring 30 acting upon o. plunger 82 ii; engagement with the valve stem "it, so thet when the valve is against the upper sect, fluid under pressure may flow from s reservoir dd through the brake valve device 56, 8t, passage as, past an open lower seat as to the velve chamber 68, and from thence to the broke cylinder it through pamsge HI and pipe '52.

The double beat valve is urged to its lower seat- 89 by an. electromagnet in the upper portion of the casing, which when energized forces a plunger 30 downwardly to urge the double beat valve to its lower seated position, and thereby cut oil the supp y of fluid under pressure to the brake cylinder.

The release magnet valve section 62 comprises a casing defining a valve chamber 82, having constant communication with the brake cylinder by way of passage 84 and pipe I2, and having disposed therein a valve 96 which cooperates with a seat 98 to control the release of fluid pressure from the brake cylinder to the atmosphere, by way of a chamber I00, passage I02 and the safety valve device 66.

The valve 96 is urged toward seated position by a spring IN, and to unseated position by an electromagnet in the upper part of the casing which, when energized moves a plunger I06 downwardly into engagement with the valve stem to unseat the valve.

The inshot valve section 64 comprises a casing defining a valve chamber I08 having communication with the reservoir 84 by way of passage I I0, pipe 86 and brake valve device 56. Disposed in the valve chamber I08 is a ball valve II2, which is engaged by a stem II4 associated with a piston II6 operatively mounted in a. chamber H8, having constant communication with the atmosphere by way of a passage I20.

The ball valve H2 is urged to unseated position by a spring I22 acting to urge the piston I I6 upwardly against stops I24, and when in unseated position fluid under pressure my flowfrom the chamber I08, and the reservoir 84, to the brake cylinder by way of passage I26 and pipe 12. The purpose of the inshot valve section will hereinafter more fully appear.

The safety valve device 66 is preferably 01' the type commonly used in connection with fluid pressure brake equipment, and it is, therefore, considered unnecessary to describe this device in detail.

In a like manner the brake valve device 56 may be of any of the usual types, as for example, a rotary type having the usual release, application and lap positions and it is, therefore, not considered necessary to describe in detail this device.

The electromagnet controlling operation of the double beat valve I4 in the supply magnet valve section 60 has one terminal thereof connected to the aforementioned contact 24, while the electromagnet controlling operation of the release valve 96 in the release magnet valve section 62 has one terminal thereof connected to the aforementioned contact 26.

The contact I8 carried by the pendulum I0 is connected to a source of current supply, as for example, a battery I26, which has its other terminal connected to the remaining terminal of each of the aforementioned electromagnets.

It will thus be apparent that when the pendulum I0 swings to the right, and its contact I8 engages the contact 24, the electromagnet controlling operation of the supply valve 14 will be energized, and when the contact I8 engages the contact 26 the electromagnet controlling operation of the release valve 86 will be energized. The purpose of this will appear presently.

In describing now the operation of the embodiment of my invention shown, it will be assumed that a vehicle or train equipped therewith is traveling on a level trackway, but it will, of course, be appreciated that successful operation of this or any other embodiment of the invention will be similar on either downhill or uphill grades.

When it is desired to accelerate a vehicle from rest, the control motor 40 of the acceleration control apparatus is connected to a suitable source of supply, as by the closing of a switch. This motor will then cause rotation of the drum 88 at a speed which is predetermined by the speed of the motor 40 and the relation of the worm and worm gear 42.

The first movement of the drum 30 connects the motor armature 28 and series field 30 to the source of current supply, with all of the resistance unit 36 in series therewith. With the vehicle motor thus energized it will produce acceleration of the vehicle in accordance with the current supplied thereto.

I1 the vehicle is heavily loaded the vehicle motor will require greater current to produce a given rate of acceleration than when lightly loaded. The control motor 40 is designed to drive the drum 38 at a rate which will cause current to be supplied to the vehicle motor at a rate which will cause the motor to accelerate the vehicle at a desired maximum rate when heavily loaded. The increased adhesion between vehicle wheels and rails due to the load in the vehicle will permit this.

The relay 46 is designed to open contacts 48 and hold them open so long as current above a predetermined value flows in the relay winding. This current is of course proportional to the current supplied to the vehicle motor, and, as will be seen presently, may correspond to a value of vehicle motor current which causes the motor to exceed the desired maximum rate of acceleration, or to excessive overload current.

With the resistance device 52 in series with the relay 46 the vehicle motor current which produces the desired maximum rate of acceleration will not cause the relay to open its contacts. But when the desired maximum rate of acceleration has been exceeded, the pendulum I0 has swung far enough to the left to cause its contact I6 to bridge contacts 20 and 22. This shunts the resistance device 52 and the increased current which immediately flows in the relay winding is sufficient to cause opening of contacts 48.

Were the resistance device 52 omitted, the relay would still be energized when contacts 20 and 22 are bridged. But by providing the resistance device 52 in the manner shown the relay will open its contacts 48 before contacts 20 and 22 are bridged when the motor current greatly exceeds the normal maximum full load current, as when the brakes are draggi on the wheels during acceleration, or for other reasons. This then prevents overheating of the driving motor.

Opening of contacts 48 interrupts the circuit to the control motor 40 and rotation of the drum 38 is thus arrested until the overload current diminishes below a. chosen value, or the rate of acceleration diminishes to or below the desired value, as the case may be. When the rate of acceleration is the controlling factor, contacts 48 remain open until pendulum I0 swings to the right and contact I6 no longer bridges the contacts 20 and 22. The resistance device 52 is then again placed in series with relay 46, and the current decrease thus caused in the relay winding permits contacts 48 to again close, again energizing the control motor 40 to again rotate the drum 88.

If the vehicle is lightly loaded the operation is the same, but since a lower vehicle motor current will produce the desired maximum rate of acceleration, a lower current flows in the relay winding. However, the resistance of the resistance device 52 is such that as soon as the pendulum it causes shunting of the resistance device, sufllclent current flows in the relay winding to cause opening of contacts 48. The rotation of the drum 38 is thus arrested before the current I supplied .to the vehicle motor reaches a value which would cause sliding of the wheels, which would now occur at lower motor currents, due to the lightly loaded vehicle producing less adhesion between wheels and rails.

It will thus be seen that the inertia operated device so controls the operation of the relay G6 as to cause the vehicle to be accelerated at a alesired maximum rate, regardless of the loading of the vehicle.

When it is desired to effect an application of the brakes to decelerate the vehicle, the handle of the brake valve device 56 is moved to application position, whereupon fluid under pressure flows from the reservoir 84 to the brake cylinder by way of pipe 86, passage lid, past the unseated ball valve H2, and through passage 32c and pipe lil.

At the same time, fluid under pressure will also flow to the brake cylinder through pipe 88, passage 88, past the open lower seat 89 of the supply valve l4, and through passage 10 and pipe it. The supply of fluid to the brake cylintier will, therefore, hev effected at a. maximum rate.

When the fluid pressure in the hralre cylinder has built up to a predetermined or chosen value, it will act upon the piston lit to move it downwardly against resistance of the spring i522, until he hall valve iii? is seated. Fluid will there how to the icralre cylinder only post the lower seat of the supply valve Ni, and. oueutly at a lower rate. "it will thus he seen that effecting an application the hralres fluid. initially flows to the praise cylinder a w rimum rate, and immediately thereafter the inshot valve device acts to reduce the rate.

As the vehicle begins to cleceierate with the application of the brakes, force of inertia will act upon the pendulum ill to swing it to the right.

When the contact carried thereby engages etationary contact fi l, the electromagnet control= ling the supply valve "ll-l will he energized, thereby causing the supply valve to he moved to lower seated position, and thus cutting oil? the supply of fluid under pressure to the brake cylinder.

the rate of retardation is such as to also cause the contact ill to engage the stationary contact 26, then the electromagnet controlling release valve 88 will he energized, and the release valve will be unseated to release fluid pressure from the brake cylinder to the atmosphere by way of the safety valve device 65.

in general, however, the pendulum will swing only for enough to the right to cause a cutting off of the supply of fluid to the brake cylinder, whereupon the supply will he lapped. Then as the vehicle continues to decelerate and the coem cient of friction between the rubbing parts of the brakes increases, so that the rate of retardation increases, the pendulum swings further to the right to effect a release of fluid pressure from the brake cylinder. The positioning of the con tacts 24 and 26 with respect to the contact l8, therefore, determines the rate of retardation at which the cutting off and release of fluid occurs,

regardless of the loaded condition of the vehicle.

If at any time the release of pressure from the brake cylinder causes the rate of retardation to decrease below that desired, then the pendulum till will swing far enough to the left to again admit fluid to the brake cylinder.

In normal operation, however, the pendulum usually moves first to cut off the supply of fluid. to the brake cylinder, and thereafter swings with short movements back and forth to release pressure from the brake cylinder as the speed of the vehicle diminishes, as the tendency is for the rate of retardation to increase with decrease in speed, due to the constantly increasing coefficient of friction between the rubbing parts of the brakes.

As the vehicle nears a stop, the rate of retardation will tend to increase rapidly, due to the very rapid increase in coeilicient of friction cetween the rubbing parts of the brake, but a smooth stop may be effected, since further control of the brakes may be effected by manipulation of the brake valve device 56.

The inertia operated device will, however, function to maintain a substantially constant rate of retardatiom due to braking, throughout the entire deceleration period, and the brake valve device need only he operated to initiate an application of the brakes, and to taper off the rate of retardation at the end. of the deceleration period.

Since the inertia device operates according to the rate oi retardation or rate of acceleration, it will he seen that I have provided an apparatus wherein a vehicle or train may he hoth accelerated and decelerated at desired rates, and starts and stops can, therefore, he made with greater uniformity and in. a minimum length of time.

While one i lustrative embodiment of the inv ntion has been descrlhed in detail, it is not intention to limit its scope to that embodiment A or otherwise than hy the terms of the appended claims.

l-laving now tlescrihctl my invention, what 5 claim as new desire to secure icy Letters Patout, is:

l. In a v hicle control apparatus, combina tion with driving motor, means for effecting progressive acceleration of the vehicle, and means responsive to supplied to the vehicle motor for limiting the rate of acceleration, of b means responsive a rate of acceleration for controlling said second means,

2. Vehicle operating apparatus comprising a propulsion motor, a circuit for supplying current to said motor, a variable resistor and a lined resistor in said circuit, means including a control motor for progressively varying said variable resister, a control circuit for said control motor, a relay and third resistor connected in series across said fixed resistor, said relay having contacts for controlling opening and closing of said control circuit, and means responsive to a chosen rate oi acceleration of the vehicle for closing a shunt around said third resistor.

3. 'In a vehicle control apparatus, the combination with a driving motor, of means for controlling said motor to produce acceleration of the vehicle, a relay for controlling operation of said means, a circuit for supplying current to said relay, normallyopen contacts in said circuit, and an inertia operated device for closing said contacts.

4.1n a vehicle control apparatus, the comloination with a driving motor, of a circuit for supplying current to said motor, a variable resistor and a fixed resistor in said circuit, means including a control motor for progressively cutting out the resistance of said variable resistor, a relay for controlling said control motor, a circult for connecting said relay to said fixed reill sistor, normally open contacts in said circuit, and a pendulum device adapted to be operated according to the acceleration of the vehicle for closing said open contacts.

5. In a vehicle control system, in combination, a vehicle driving motor, means including a control motor for controlling the supply of current to said driving motor, electroresponsive means responsive to the current supplied to said driving 10 motor for controlling operation of said control 530 termined degree to control operation oi said control motor, and means operated according to the rate of acceleration of the vehicle for controlling the degree of energization of said relay.

7. In a vehicle control apparatus, in combination, a driving motor, means for controlling the operation of said motor to produce a chosen rate of acceleration of the vehicle, a relay adapted when the energization thereof is abruptly changed by a predetermined amount to effect an operation or said last means to decrease the rataof acceleration, and means operated according to the rate of acceleration of the vehicle for controlling energization of said relay and operative to abruptly change the energization of said relay by said predetermined amount at the instant the rate of acceleration exceeds said chosen rate.

8. In a motor control system, in combination, a motor for propelling a vehicle, a controller for controlling said propelling motor, a pilot motor for actuating said controller, a limit means responsive to the motor current, resistance means, and means responsive to the acceleration of the vehicle and cooperating with the limit means and the resistance means to control the operation of the pilot motor, thereby controlling the rate of acceleration of the vehicle.

JOSEPH C. MCCUNE.

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