US1898242A

US1898242A - Remote control system

Info

Publication number: US1898242A
Authority: US
Inventors: Edward F Chandler
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-09-27
Filing date: 1922-09-27
Publication date: 1933-02-21
Anticipated expiration: 1950-02-21

Description

Fell'zl, 1933.

E. F; CHANDLER REMOTE coumoz. SYSTEI Original Filed Sept. 27. 1922 3 Sheets-Sheet l INVENTOR FIG. I

Feb. 21, 1933. 5 CHANDLER 1,898,242

REMOTE CONTROL SYSTEM Original Filed Sept. 27. 1922 3 Sheets-Sheet 2 ea Jib/ ,6! U L mo (,2 J ,53 64 n F 59 q l L5) 67 v I I c T w ,r" FIG. 7

INVENTQR 6., ATTORNEYS Feb. 21, 1933. CHANDLER 1,898,242

REMOTE CONTROL SYSTEM Odginal Filed Sept. 27. 1922 3 Sheets-Sheet 3 H B IMHIIIIHHI HHI llll llllflllllfllllllll M 5 V V F7Q I'INVENTOR H6. /4- awadxeg QATTORNEY Patented Feb. 21, 1933 PATENT OFFICE EDWARD I. CHANDLER, OF BROOKLYN, NEW YORK REMOTE CONTROL SYSTEM Application filed September 27, 1922, Serial No. 590,854. Renewed December 15, 1931.

ed on the valve or other device intended to be operated thereby. The invention is described herein with particular reference to the operation of valves, but it will be understood that the invention is not limited to such use but may be employed in conjunction with any other suitable device, as well known in the art.

I shall describe certain preferred forms of embodiment of the invention and then point out the novel features thereof in the appended claims.

In the accompanying drawings, Figure 1 is a plan view of one form of mechanism embodying the invention, part of the casing being shown broken away to expose the internal parts of the mechanism;

Figure 2 is a view showing a section of Figure 1 on line IIII, looking in the direction of the arrows;

Figure 3 is a vertical section of part of Figure 1, along line IIIIII, looking in the direction of the arrows;

Figure 3 is a view showing a modification of Figure 3;

Figure 4 is a view showing an elevation of the circuit controlling mechanism of F igure 1;

Figure 5 is a side elevation of Figure 4;

Figure 6 is a plan view of the mechanism 35 shown in the right-hand part of Figure 5;

Figure 7 is a circuit diagram of one system of circuit connections adapted to be used with the mechanism of the present invention.

Figures 8 and 9 are views showing face 0 and side elevations, respectively, of the member operating a switch when the device is set for manual operation;

Figure 10 is a detail view of the collar 87;

Figure 11 is a general view of one form of operating system ofmy invention;

Figure 12 is a view showing an elevation of one form of controller embodying my invention;

Figure 13 is a side elevation of the magnets of Figure 12; and

Figure 14: is a view showing a modification of Figure 7.

Similar characters of reference designate similar parts in each of the several views.

The operating mechanism illustrated in the drawings comprises an enclosed electric motor M, which, through mechanism hereinbelow described, operates a power take-off shaft 1, which shaft, through suitable

external gearing

2, 3, (see Figure 11) operates the stem 4 of a valve V.

The entire operating mechanism is enclosed in a casing C, which casing is detachably mounted by means of bolts 6 on a plate 5 integral with or secured to the valve housing. A hand wheel 7 may be provided for operating the valve manually, when desired, this hand wheel being loosely mounted on the power take-01f shaft 1 and provided with a suitable mechanism indicated at 8 for looking the hand wheel to the shaft when it is desired to effect manual operation of the valve. The mechanism for transmitting the rotation of the motor to the power take-off shaft 1, comprises spur gearing 9 and 10 (Figures 1, 2, 3 and 3) a lost-motion drive worm gearing WV and a clutch K. The spur gearing comprises a pinion 9 mounted on the shaft 11 of the motor, which pinion cooperates with the gearing 10 mounted on a counter shaft 12. The gear 10 is not locked to shaft 12 but transmits its rotation thereto by means of the lost-motion connection L. This connection comprises a collar 13 affixed to shaft 12 and provided with a lug 14 adapted to engage a corresponding lug 15 provided in the face of gear 10.

When the motor is set into operation, it encounters no load until lug 15 engages lug 14, this period being, under normal operating conditions, an almost complete revolution of gear 10, so that the motor will have had an opportunity to gather speed and momentum before it is subjected to the load of operating the valve.

The rotation of counter shaft 12 is transmitted to the power take-off shaft 1, by means of the worm gearing W, the worm 16 being mounted on the shaft 12 and the worm wheel 17 on the power take-off shaft 1. The worm 100 wheel is free to turn on the power take-off shaft and a clutch K is provided for transmitting the rotation of the wheel to the shaft. The clutch consists of a sleeve18 free to slide longitudinally on the shaft but constrained to rotate therewith by means of a feather key 19. The adjacent faces of sleeve K and wheel 17 are provided with inter-engaging projections 21 and 22 for causing the shaft and the sleeve to rotate in unison when the projections are in engagement with each other.

It will be observed that the power takeoff shaft is normally locked against movement, owing to its direct mechanical connection to worm 12, which worm constitutes a substantially non-reversible driving connection between the motor and shaft 1. The valve, therefore, cannot be operated by force applied directly to the valve or to the external gearing. The shaft 1 and the valve are thus positively held in the positlon to which they were operated last.

Another feature resulting from the above described construction consists in the fact that when the worm 12 is caused to cease its rotation, as by the deenergization of the motor at the end of the valve operating stroke, the momentum of the parts beyond the worm, namely the worm wheel 17, power take-off shaft 1,

gears

2 and 3, and the operatlngparts of the valve proper, cannot cause a drift of the valve beyond the desired point, the movement of these parts being positively termlnated by the worm as it ceases its rotation.

The operation of the valve may thus be controlled within precise limits and undue amming of the parts can be entirely prevented.

Because of its capability to exercise such accurate control, the mechanism is particularly adapted for the operation of valves which are run at high speeds to effect quick operation. The operating parts of such valves gather a large momentum owing to the high speed and these parts would be unduly jammed or even broken if their momentum were not properly absorbed before the operating member strikes its seat. This is particularly true of globe valves which have a fiat seat and which therefore must be seated very accurately, there being no free play between the parts, as for instance in a gate valve. The operating mechanism of the present invention is well adapted for the above types of valves by virtue of its direct connection to the worm which, when the motor ceases to rotate, quickly absorbs the momentum of the parts beyond the worm wheel and thus brings the mechanism accurately to a stop.

Another feature of the above-described construction consists in the provision of the lostmotion device L between the motor and the worm. In this construction the hammer blow imparted to the mechanism when lug 15 strikes lug 14, to initiate the operation of the valve, is partially absorbed and cushioned by the action of the worm, so that it is transmitted to the operating mechanism as a powerful force rather than a shock; a force which is much greater, however, than that normally exerted, due solely to the driving force of the motor under normal conditions. The force thus exerted has enough suddenness to detach the valve if tightly driven in its seat, and is greater than the force normally exerted, and yet the motor is not called upon to deliver any excessive amount of power such as would be the case if the resistance offered by the valve had to be overcome without the assistance of the lost motion device. In other words, the lost motion device permits the storing u of force in the armature of the motor acting as a flywheel, and assisting the motor at the required moment, in delivering the necessary power without overload conditions being created in the circuit. The present mechanism thus eliminates the distinct shock or hammer blow characteristic of the previous forms of mechanisms in which the lost-motion device is directly associated with the power take-off shaft, which construction sometimes results in injury to the operating mechanism itself or to the mechanism operated by the power take-off shaft. The present mechanism thus retains the powerful turning force desirable for initiating the valve operation but eliminates the undesirable shock generated by the previous types of mechanisms.

Just before the end of a valve-operating stroke, the motor is automatically brought to rest by means of a limit switch mechanism S, mounted in the front end of easing C, where it is rendered conveniently accessible by a cover plate 150. This mechanism, illustrated in elevation in Figure 4, consists of

contact fingers

54 and 55, which fingers are mounted on and electrically insulated from levers 65 and 66, respectively, pivoted at 67 and 68. These levers are normally held by means of a tension spring 69 in such position that the contact fingers are in engagement with the outer pairs of contacts designated 23 and 24. Lever 66 is illustrated in the drawings as occupying this position, whereas lever 65 is illustrated in the reverse position, in which it bridges contacts 25. Both of the levers are retained in the positions illustrated by means of the tension spring 69, which spring serves to hold the levers in engagement with dogs 70 and 71 provided on a common pivot 72. The switch mechanism is operated by means of a pair of crank arms 47 and 48 fixed on a shaft 46, which shaft derives its motion from the power take-off shaft 1 through bevel gearing 42, shaft 43 and spur

gearing

44 and 45.

In Figure 4 the parts of the limit switch are shown in the positions which they assume when the valve operated by the shaft 1 is in one of its extreme positions, say the closed position. \Vhen, under these conditions the circuit of the motor is closed by controlling mechanism hereinafter described, so as to cause an opening movementof the valve, the cranks 47 and 48 are caused to turn clockwise, thus causing the roller 49 of crank 47 to engage lever 66 and turn the same clockwise until dog 71 engages a shoulder 76 of the lever. In this position the contacts 24 are open and contacts 26 are closed.

The closing of contacts 26 is thus effected immediately after the beginning of the valve opening operation. The importance of this feature will be seen from following parts of the description.

As the operation of the valve proceeds, crank arms 47 and 48 continue their clockwise movement until roller 49 of crank 47 engages the surface 74 of dog 70, thus lifting the dog out of notch 76 in lever 65. As a consequence, this lever is turned clockwise by spring 69 to a. position at which dog engages the shoulder 77. Contact finger 54 v is thus snapped out of engagement with contacts 25 and caused to bridge contacts 23. The opening of contacts 25 causes the decnergization of the motor, as hereinafter described, so that the parts are brought to a standstill.

The operation of the switch mechanism during a valve closing movement is similar, in that it brings about a closure of contact 25 immediately after, the commencement of the valve operating stroke, and an interruption of contacts 26 and closure of contacts 24 at the end of the valve operation.

The circuits governed by the limit switch mechanism are illustrated in Figure 7. In this figure the motor is indicated diagrammatically at M and the limit switch at S. A controller for governing the valve operation is indicated at O. This controller will ordinarily be mounted in a convenient location remote from the valve, as for example, on the switchboard of a power plant, a conduit 150 serving to house the control wires connecting the controller with the operating mechanism, as illustrated in Figure 11. The controller comprises signal lamps G and R for indicating, respectively, that the valve is in an open or a closed position, a. signal lamp U for indicating that the valve mechanism is in position for manual control, and a drum controlling device D for controlling the power operation of the valve.

In Figure 7 these various parts are illustrated in the relative positions occupiedwhen the valve is in one of its extreme positions, namely, the open position. The signal lamp G (which may be green in color), is energized by current flowing from line through a manually operable switch 51, hereinafter referred to, the field 53 of motor M, contacts 26 of limit switch S, conductor 90 and signal lamp G back to the line.

To effect a closing of the valve, the drum'of the controller is turned to the left until

segments

56 and 57 engage

contact fingers

58, 59 and 60, 61, respectively. Current now flows from line through switch 51, motor field 53, contacts 26 of the limit switch, conductor 90, contact segment 57, motor armature 62, contact segment 56 of the controller and back to the line. It will be observed that the circuit of the green lamp remains closed so that this light continues to burn. The current in the circuit just traced causes the motor to commence operation in such direction that the valve is moved by the mechanism hereinbefore described, toward the closed position. As soon as this operation is commenced, the limit switch S is operated to close contacts 25, as hereinabove described, so that the circuit for signal lamp R (which may be red in color) is completed, thus causing this lamp to glow. The response of the a ve to the operation of the controller is thus indicated at the controller by the energization of both of the signal lamps. At the completion of the stroke the limit switch opens contacts 26, as hereinbefore described, so that the green lamp G is extinguished and the motor M is de-energized by the opening of the armature circuit. The valve operation is, therefore, terminated. Only the red lamp of the controller is now illuminated, thus indicating to the attendant that the valve is in the closed position.

The operation of the valve to the open position is similar, being brought about by throwing the handle of the controller to the right, so that the

contact segments

63 and 64 are returned to the positions indicated in Figure 7. Current is thus caused to flow through contacts 25 of the limit switch and throu h motor armature 62 in the reversed direction, so that the valve is operated to the closed position. Contacts 26 are bridged immediately upon the beginning of a stroke of the valve, as hereinbefore described, so that both si nal lamps are again energized to indicate t at the valve is responding to the controller. At the end of the stroke the contacts 25 of the limit switch are re-opened and thus effect the de-energiation of the motor and the de-energization of the red signal lamp, so that the parts are returned to the positions illustrated in Fi V ure 7.

It will be observed that by virtue of the limit switch mechanism the motor is automatically brought to a stop when the valve operation is completed. The de-energization of the motor may be timed very accurately by adjustment of angular positions of cran arms 47 and 48 on shaft 46. Each crank may be set in such position that it will bring about the opening of the motor circuit at an instant such that the valve will be completely closed but not unduly jammed when the parts are brou ht to rest.

As hereinbef ore observed, the momentum of the external parts of the operating mechanism is incapable of causing an undue drift of the mechanism by virtue of the direct connection between the Worm 12 and the power take-01f shaft 1. The drift occasioned by the free rotation of motor M, after its de-energization, will, in certain instances, be of no consequence. However, even this drift may be eliminated by providing a brake for bringing the motor armature to rest so that extremely accurate control may be effected.

Figure 7 illustrates an arrangement in which the braking action is obtained by short circuiting the armature of the motor. In this figure, reference character X designates a relay having a high resistance winding, the contact 100 of which relay serves to short circuit the armature circuit when the relay is energized. When, upon the completion of a valve closing operation the contacts 26 are opened to de-energize the motor armature, contacts 24 are closed and thus establish the following circuit through relay X :from line, through switch 51, motor field 53, conductor 30, winding of relay X, conductor 31, contacts 24, conductor 90, contact segment 57, motor armature 62, contact 56 to line. The relay is thus energized and closes its contact 100, thus short-circuiting the armature and causing the same to come to a rapid stop. Drift of the operating mechanism is thus successfully prevented.

If the controller is now operated to establish the valve opening circuit, the above-described circuit for relay X is interrupted by the contacts of the controller, so that the short circuit is removed from the armature before the connections from the valve opening stroke are completed. At the end of the opening stroke, the operating circuit is broken at contacts 25, as hereinbefore described, and the circuit for relay X is established through contacts 23, segment 63 of controller D, motor armature62 and segment 64 of the controller to line. Current in this circuit causes the relay X to close its contact, thus again short circuiting the motor armature and bringing the same to a rapid stop. This short circuit is broken only when the controller is again reversed to return the valve to its open position, as will be readily understood.

For the purpose of rendering the valve capable of being operated manually, the mechanism is provided with a hand lever 80 which serves to control the position of sleeve 18 on shaft 1. This sleeve, as hereinbefore observed, is slidable on shaft 1 and when moved away from worm wheel 17 a sufficient distance to prevent projections 21 and 22 from engaging each other, renders the motor incapable of effecting operation of the valve. Movement of the clutch sleeve is effected by means of a forked lever 81 provided with studs 82 for entering the groove 83 in the circumference of the sleeve. Lever 81 is rotatably mounted on a shaft 84, which shaft is supported in

bearings

85 and 86 provided in the casing of the mechanism. The handle 80 is provided on the exterior of the casing for turning the shaft through an angle suificient to bring about the desired movement of sleeve 18. The movement of shaft 84 is communicated to the forked lever 81 by means of a collar 87 keyed to the shaft and provided with a recess 88 for receiving a stud 88" mounted in the lever. Clockwise movement of shaft 84 (as viewed in Figure 5) for bringing about disengagement of the clutch, is positively communicated to lever 81 by engagement of the pin with the left extremity of recess 88.

Counter-clockwise movement of shaft 84, however, causes merely movement of the collar 87, so as to permit lever 81 to follow this movement if it is not otherwise restrained. A spring 89 mounted on a stud 99 of the instrument and cooperating with a stud 91 of lever 81, serves to cause the lever to follow the movement of shaft-84. If, however, the relative postions of clutch projections 21 and 22 are such that they abut each other when sleeve 18 is'moved toward worm wheel 17, the lever will remain in an intermediate position with its movement only partly completed. When subsequently the worm wheel 17 is operated by the motor through an angle suflicient to cause the disengagement of the projections, the sleeve will snap into engaging position.

It will be observed that by means of the above-described mechanism the handle 80 is free to be moved into clutch-engaging position even though the elements of the clutch are in such relative positions that an engagement of the clutch cannot be effected. This feature is of importance because it permits the mechanism to be set at any time into condition for power operation.

For the purpose of retaining the parts in position for manual operation, the handle 80 is provided with a button 92 which governs a pin 93, which, by means of a spring 94 is biased to engage a corresponding opening in the casing of the mechanism, as shown in Fig. 1.

The hand lever 80 governs not only the operation of the clutch K but controls also the operation of the switch 51, which, as will be observed from Figure 7, serves to disconnect the motor and its control circuits from the line, and to complete the circuit of a signal lamp U (which may be white in color) at the controller so as to indicate to the attendant that the valve is set for manual operation and cannot be moved by the power mechanism.

The mechanism for operating switch 51 comprises a link 101 pivotally associated with a lever 151 mounted on shaft 84 between lever 81 and collar 87, and constrained to follow the movement of the collar by means of a pin 152 which enters a hole 153 in lever 151. The operation of the switch 51, therefore, is controlled positively by lever '80, the connections being such that when the lever is in the lower position, circuit is established through the power operating mechanism, and when in its upper position, circuit is established through signal lamp U. Lever 151, it should be observed, is provided with a recess 88, similar to recess 88 in collar 87, for receiving pin 88 and permitting relative angular movement between the

levers

81 and 151.

By virtue of the previously described mechanical construction which renders lever free to be placed into its lower position even though the clutch parts are in obstructing positions, the circuit through the operating parts can be fully established. It is thus possible to give the operator at the switchboard control of the valve at any time.

It will be observed that the entire operating mechanism is enclosed in a casing and is attachable as a unit to the valve or other device which is governed thereby. The motor M is provided with a separate housing 102, which by bolts 103 (Fig. 3), is secured directly against a plate 104, which plate serves as a bearing for the shaft of the motor, and also as a bearing for the countershaft 12. The plate is held in position on the casing of the mechanism by means of machine screws 105. The motor, therefore, is readily detachable from the operating mechanism. The casing of the mechanism and the housing of the motor are thus held in direct juxtaposition and the motor leads 106 are passed directly into the casing of the operating mechanism through a passage 107 in plate 104. The necessity of a separate conduit for the leads is thus entirely avoided. From the mechanism casing the conductors 107 are led into conduit 108 together with the control wires associated with the terminals of the limit switch.

Although in the above-described specific form of embodiment the removal of the motor necessitates the detachment of plate 104, it will be understood that the motor and its housing may be constructed so as to be removable without disturbing other parts of the mechanism. Such construction is illustrated in Figure 3A, in which the plate 104 is provided with an opening 160 for receiving a boss 161 integral with the motor casing 102. This boss constitutes the bearing for the motor shaft and is of a size slightly larger than gear 9, so that this gear may be passed through the opening 160. The motor casing is secured to the plate 104 by means of machine screws 162, so that by unloosening the screws, the motor together with gear 9 may be withdrawn. The conductor lead 106 of the motor is attached to a plug 163 provided in the motor housing, which plug forms part of a detachable connector 165, which connector is mounted in plate 104 and electrically insulated therefrom. A lead 106 is associated with the connector and leads through the easing into the limit switch and conduit 108. It will be observed that by virtue of this detachable connection the conductor lead need not be severed or detached when the motor is removed, and the detachment or replacement of the motor is thus exceedingly facilitated.

Figure 14 illustrates a modification of Figure 7, in that the short circuiting of the armature is accomplished without the use of a relay, but by additional contact provided on the drum of the controller. This drum, as indicated in Figure 12, is provided with a control handle 170, the pointer 171 of which is biased to a vertical position by means of a spring 172. In this position the stationary contact points 58, 59, 60, 61 and 62 are out of engagement with the cont-act plates of the drum, so that current is applied to none of the control circuits. The drum may be locked in either of its extreme positions, however, by means of a locking mechanism, comprising a pair of

magnets

173 and 174, which magnets cooperate with a common armature 175 mounted on a lever 176 provided with a dog 177, which dog is adapted to co-act with

recesses

178 and 179 in drum D. Normally, a spring 180 serves to hold the lever 176 in engagement with a back stop 181, so that the dog 177 is out of contact with the drum.

Magnets

173 and 174 are inserted in series with the conductors and 90 of the control circuits for motor M, these circuits being the same as described in connection with Figure 7, differing therefrom only in that the connections for relay X are omitted.

The

contact plates

56, 57, 63 and 64 of the drum correspond. respectively, to the contact plates similarly designated in Figure 7, and govern the operation of the motor in a similar manner. Interposcd between these sets of contact plates, however, are

additional plates

182 and 183, 182 and 183*. which plates are electrically connected with each other by means of resistances 184 and 184. The operation of this type of controlling system is as follows:

To effect a closing movement of the valve, the handle 170 of the controller is turned to the left until dog 177 of lever 17 6 engages a shoulder 178 on drum D. At this point index 171 of the handle registers with the mark 7' on the face of the controller mechanism. as shown in Figure 11.

Contact plates

56 and 57 now are in engagement with the stationary contact points of the controller, so that the current flows from line through contact plate 56, motor armature, contact plate 57, magnet 174. contacts 26 of the limit switch, motor field 53 and switch 51, to line. The current in this circuit causes the motor to operate the valve into its closed position and effects also the energization of magnet 174, with the result that this magnet causes the dog 177 to enter slot 178, thus holding the drum of the controller in position against the action of spring 172. The handle of the controller may, therefore, be released.

When the valve closing operation is completed, contact 25 having in the meantime been closed, contact 26 of the limit switch opens, as hereinbefore noted, thus de energiz ing the motor and magnet 174. This magnet thus releases its armature so that the spring 180 withdraws dog 177 from recess 178, so that spring 172 returns the controller to its initial position. During this movement contact plate 182 bridges contact points 59 and 61, thus short-circuiting the motor armature and bringing about the desired braking effect. The contact 183, at the same time. is engaged by contact point 62, so that resistance 18l is introduced into the field circuit with the result that the field current for the period of armature short circuit is reduced, so that too violent a braking effect is prevented. The resistance of the element 184 is such that it will be possible to obtain exactly the required amount of braking effect for any particular installation. If desired, the resistance elements 184 and 18 1 may be made adjustable so that the operator may regulate the braking action in accordance with the requirements of the particular installation with which he is concerned.

After the motor armature has been arrested, the

contact plates

182 and 183 pass from under the stationary contacts 58 to 62, so that the short circuit is removed from the armature and the current is taken off the motor field. The return of the controller drum to the neutral position is preferably retarded by any suitable mechanism well known in the art, so that 'the period during which the short circuit is applied to the motor is of sufficient duration to bring the armature fully to. rest.

The operation of the mechanism in the reverse direction is similar, the short-circuiting of the armature being effected in this instance by contact plate 182 and the resistance introduced into the field circuit being indicated by element 184.

A push button switch 200 is preferably provided at the controller in series with contact 60 for the purpose of enabling the operator at any time to de-energize the motor and thus arrest the valve-operation. This switch is of importance not only for use in emergencies. but also to permit the operator to effect only a partial operation of the valve or to permit him to return the valve to its initial position (if he finds he has made a mistake), without having to wait for the valve to complete its operation. If no such switch 200 were provided the controller would be held locked by

magnets

178 and 174 in one extreme position orthe other until the valve had completed its operation.

The provision of means for returning the controller arm to neutral independently of the action of the locking means therefor, is also extremely important when more than one control station is provided.

llhen such is the case. it is well nigh imperative to use a controller arm with automatic return to neutral. and therefore generally held by suitable locking means at its operative positions. Otherwise a case might be conceived where two controllers are used for the same unit. the controller arm of one being set, say at the closed position after the valve has been moved to such position without the controller arm having been returned to neutral. If the controller arm at the other control station is now set for opening, and assuming that it may be operative notwithstanding the other arm being set at closed, the valve will open; but as soon as it has reached the end of its travel, the former controller arm will once more be operative, and the valve will immediately reclose, and so on, in continuous succession. An automatic return to neutral of the controller arms is therefore necessary. and this, in its turn, makes the insertion of means for returning the controller arms to neutral notwithstanding the action of the locking means, a vitally important feature, which is new in this art.

lVhat I claim is:

1. In combination, a motor, a controller therefor, circuits for operatively associating the controller with the motor, means operative during an operation of the motor for holding the controller in an operative position, means for causing the controller to move to an inoperative position after the completion of an operation of the motor, and means operated by said controller during said movement for applying a shortcircuit to the motor armature, and means for producing a decrease in the field current during the period of short circuit.

2. In combination, a motor, a controller therefor, means for locking said controller in an operated position, means for unlocking said controller at the completion of a motor operation, and mechanism manually operable at the controller for at times effecting an unlocking of the controller and a de-energization of the motor.

3. In a device of the class described, the combination, with an operating mechanism, a member driven thereby, an electric motor driving said mechanism, and an electric circuit controlling the operation of said motor, of means located at a distant point controlling the operation of said circuit, and means adapted at one operation to both disconnect said driven member from said operating mechanism, and to prevent operation of said circuit by the distant control means, and including means for re-establishing the controlling circuit in advance of the reconnection of the driven member and the operating member.

4. In a device of the class described, the combination of an operating mechanism, a member driven thereby, an electric motor driving said mechanism, an electric circuit controlling the operation of said motor, means located at a distant point controlling operation of said circuit, a manually operable member adapted to disconnect said driven member from said operating mechanism, and means controlled by said manually operable member, to prevent operation of said circuit by the distant control means when said driven member is thus disconnected, and including means for re-establishing the controlling circuit in advance of the reconnection of the driven member and the operating member.

5. In a device of the class described, the combination, with an operating mechanism, a member driven thereby, an electric motor driving said mechanism, and an electric circuit controlling the operation of said motor, of means adapted to both disengage said driven member from said operating mechanism, and interrupt said circuit, said means being adapted to re-establish said circuit in advance of and independently of the reengagement of said driven member.

6. In a device of the class described, the combination, with an operating mechanism, a member driven thereby, an electric motor driving said mechanism, and an electric circuit controlling the operation of said motor, of means adapted to both disengage said driven member from said operatingmechanism, and interrupt said circuit. said means being adapted to re-establish said circuit independently of the re-engagement of said driven member, and means for simultaneously or subsequently re-engaging said driven member to said operating mechanism.

7. A unitary driving mechanism for valves and the like, comprising a casing adapted to be mounted on to the device to be driven thereby, and an operating mechanism including a motor, a limit switch associated with said operating mechanism for terminating the operation of the motor at a predetermined instant of time, and means governed by said limit switch for exerting a braking action on said motor upon the tcrmi nation of its operation, all the mentioned ele ments being enclosed within said casing.

8. In a valve operating unit, a motor, an operating shaft, means for starting the motor, means for transmitting the rotation of said motor to said shaft positively, said means comprising mechanism for causing the motor to spin without load at the start, and then automatically to start the shaft by impact, rotary, valve operating means associated with the valve, and a one-way driving connection inter )osed between the op t ing shaft and said operating means for en abling the shaft to rotate said op in means, but preventing said ope atin means from relating the shaft so 'tl' f. i i operating shaft upon de-energizaticn of the motor is prevented.

9. In a valve operating unit, :2. operating shaft, means motor, means for transmittin of said motor to said shaft 1' means comprising mechan i I the motor to spin without load at the star and then automatically to start the shaft y impact, rotary, valve operating means associated with the valve, and mechanism form ing a non-reversible driving connection between said rotary operating means and the shaft whereby the momentum of said rotary operating means is prevented from turning the shaft when the motor ceases to rotate;

10. In a valve operating unit, a motor, an operating shaft. means for starting the motor. means for transniitting the rotation of said motor to said shaft positively, said means comprising mechanism for causing the motor to spin without load at the start, and then auton'iatically to start the shaft by impact, rotary, valve operating means associated with the valve, and mechanism forming a non-reversible driving connection between said rotary operating means and the shaft whereby the imimientum of said rotary operating means is prevented from turning the shaft when the motor ceases to rotate, and means for arresting the free rotation of the motor armature whereby the momentum of said armature and its associated parts is prevented from causing said non-reversible connection to drift beyond a predetermined position.

11. In combination, an operating shaft, a motor, means for starting the motor, means for transmitting the rotation of the motor positively to the operating shaft, including a lost motion device for causing said motor to spin without load at the start, and then to startthe shaft by impact. rotary, valve operating means operated by said operating shaft, worm gearing for transmitting the ro tation of the operating shaft to said rotary operating means, and a clutch permitting substantially no lost motion interposed between the worm wheel and the valve operating means.

In testimony whereof I have atlixed my si nature to this specification.

EDIVARD F. CHANDLER.