US2363929A - Electric operator for opening and closing doors - Google Patents

Description

Nov; 28,1944] .1. H. BANKS ETAL 2,363,929

ELECTRIC OPERATOR FOR OPENING AND CLOSING DOORS Filed Spt 22, 1942 2 Sheets-Sheet 2 IN VEN TORS JHMES H. Bfi/YKS H/IRRY R. JORGE/V6 Patented Nov. 28, 1944 ELECTRIC OPERATOR FOR OPENlN AND CLOSING DOORS James H. Banks, Rahway, Scotch Plains, N. J., assl plies Company, Incorp corporation or New Je and Harry R. Jurgens,

gnors to Elevator Suporated, Rahway, N. J., a

- Application September 22, 1942', Serial No. 459,278

9Claims. (01'. 268-53) This invention relates to. electric operators for opening and closing doors or the like, and provides improvements therein. I

It is desirable, especially in elevator practice, to have doors open and close with reasonable speed. Heretofore this .has been accomplished. with electric operators by using a motor having somewhat greater power than required merely to open and close the door, in order to obtain rapid acceleration in the initial part of the door moveand the end'result is that the opening and closing interval is substantially constant for all the various doors.

ment from anopen or closed position, and then,

when the door has reached a predetermined point, or distance from" its initial starting position, in

The present invention also acts to compensate for voltage variations in the line connected to the motor. When' there is an excess of voltage the speed control device will act more quickly than at normal voltage, and when there is ajde ficiency of yoltage, themotor will continue to accelerate longer than at normal voltage.

Such problems heretofore have been met only in an unsatisfactory way and by the use of rather its movement at which the acceleration would Y normally reach a predetermined speed, the motor is retarded to prevent further acceleration, the door movement being continuedunder the combined effect of momentum and the retarded force of the motor. Such means, however, suffer from the disadvantage that when the direction of movement of the door is reversed during its opening or closing movement or when the door-movement is stopped or checked at an intermediate point by an outside obstacle or force, as by collision with a person or by the hand of a person to avert collision, etc., the remainder of the opening or closing movement is slow, or stalled.

sluggish or relatively The present invention overcomes. the abovestated objections and deficiencies of prior electric operators for opening'and closing doors. It provides an electric operator which accelerates until a predetermined speed is attained immediwhatever the position of the door intermediate its fully opened or fully closed position, and the lar conditions, of prior electric operators, overcome.

-- sluggish door movement, or stalling, under simi- In elevator practice the car-dooroften effects the opening and clcsing of the hatch-way door at the various floors through coupling means.

These hatch-way doors have variations in the I effort required to open and close them, as forexample, frictional differences, weight difference, etc. The present invention takes care of these variations in a very simple manner. The motor will continue to accelerate until it reaches the predetermined speed at which the speed control device acts, so that when the'load 0n the motor is lighter than normal the speed control device will act quickly and when the load is heavier than normal the motor will accelerate longer,

rated.

complicated means.

The invention is especially applicable to the elevator'art, and may receive various embodiments in that and other arts. In the elevator art there are a number of types of door closures, and many-electrical ways. of effecting the doormovements, and of effecting the elevator movement, and the invention mayhave difierent embodiments bestsuited to the system of elevator control and operation with which it is incorpo- The embodiments of the invention are illustrated in the. accompanying drawings, wherein: Fig. 1 is a diagrammatic view illustrating a simple and general application of the invention to the opening and-closing of doors; and

Fig. 2 is alsoa diagrammatic View illustrating one mode ofapplying the invention to the opening and closing of a'door on an elevator-car, the hoisting and signalling means being omitted from this illustration.

Referring to said drawings, D designates a door, gate or the like, which is to be moved by the electrical operator, and M designates an electric motor forming part of the electrical operating means; the power of which is applied to the opening and closing of the door through suitable connections C. These connections have various forms.

As shown in Fig. 1 the connections comprise a pinion cl meshing with a gear 02, and a link 03 connected at one end to a crank pin at on the gear 02, and at its other end .to a lever 05. The lever is pivoted at one end as indicated at 06, and at its other end is connected toga link 01 which, is connected to the door D, as indicated at 08.

In Fig. 2- the connections 0 comprise a pinion clll meshing with a gear cll. A link cl2 connected at one end to a crank'pin cl3 on gear all and at its otherend to a lever cl5 by a pin clB; To the opposite end of lever cl'5 is a link cl 8 connected by pins cl 9 and 020 to the opposite end of lever cl and to the door D. The arrangement of the crank pin cl3 is such that the crank pin travels in an arc in the neighborhood of dead center as the door approaches its fully closed or fully opened position, thereby providing for a mechanical slowing down of the door movement as the door closely approaches its fully opened or fully closed position.

The electrical operator further includes retarding meansand a control device SC responsive to the speed of the motor M and operating at a predetermined speed to cause said retarding means to act. As shown in the drawings, the retarding means may be electrical and act on the motor to reduce its power, and thereby its speed. The motor M is one having greater power than is required to open or close a door in a predetermined time. For example, if it be predetermined to allow one second for a door to move from closed to open position the power of motor M without retardation would be such as to effect the opening in considerably less time. The effect of the extra powered motor and of the retarding means is that in the first part of the door opening movement the motor operates at full power, thereby quickly accelerating the speed of opening of the door, and, when the door opening movement has reached a predetermined speed, the retarding means comes into action to retard the door opening movement. The degree of retardation is usually so contrived that the speed of opening reached when the retarding means comes into action is approximately maintained until shortly before the door reaches its fully open position; that is, the eifect of the retardation is to stop further acceleration of the door opening movement under the action of the motor.

The action of the motor and of the retarding means on the door closing movement is substantially the same as in the door opening movement, though in practice it is often arranged to have the time of door closing somewhat longer than the time of door opening, for example, 2 seconds. A mode of efiecting this differential is hereinafter described.

As heretofore stated, the action of the retarding means, according to the present invention, is under the control of the speed of the motor (or of a part moving synchronously therewith), so that whenever the movement of the door in an intermediate position is reversed, or whenever the speed of the door closing movement drops below the speed at which the retarding means goes into action, whatever the intermediate position of the door, the resumption of the door movement is effected under the full power of the motor.

The speed control device SC is advantageously in the form of a rotatably mounted permanent magnet p in the field of which is mounted a rotatable part p2 usually of nonferrous light weight metal. When the magnet p is caused to rotate, its magnetic field generates eddy currents in part 102. These currents in turn set up a magnetic field of their own, causing a magnetic drag between the magnet and the rotatable part p2. The eddy currents and the resultant magnetic drag increase as the speed of rotation of the magnet p is increased. The permanent magnet p is rotatably connected in a suitable manner to the motor M, as by means of pulleys p4 and p5 and a belt p6, and thereby rotates at the same speed, or at a speed proportional to, the speed of the motor. The part p2 may move in response to the magnetic drag of the rotating permanent magnet p. The function of the speed control device SC is to bring into operation the retarding means upon the motor reaching a. predetermined speed in the course of its acceleration as will now be more fully described.

Referring to the form of embodiment shown in Figs. 1 and 2, the rotatable part p2 has an arm p'l and there are two springs pill, pl l, on opposite sides of the arm p! but not attached thereto which act to oppose rotation of the arm pl and consequently of the rotatable part p2. The springs pill, pl l, are connected to pivoted arms p12, pl3, which arms are stopped by pins pl5, pit, so that the arm pl is acted on by only one spring at a time. Connected to the rotatable part p2 are bridge contacts pie, pi and these are conveniently mounted on the arm as shown. These bridge contacts 10 i 8, 'p l 9, close circuits which bring a resistance into the circuit of motor M to thereby reduce its power, a description of which will now follow with reference to each'figure of the drawmgs.

Referring to Fig. l, the motor may be, as here shown, a universal series motor, operable from a single phase alternating current supply or from a direct current supply. Motor M has a resistance R in its circuit which functions as a retarding means.

In this embodiment the fiow of current through the motor is not entirely interrupted, a feeble current being passed through the motor in the fully open and fully closed position of the door, so that the motor may act as a positive means for holding the door in its open and closed position. A resistance RA may be provided which cuts down to a small amount the current which flows through the motor in the fully open and fully closed positions of the door.

The resistances R and RA'may be lay-passed through a circuit which includes bridge-contact dl3 of relay RE. The circuit through the electromagnet of relay RE is under the control of the bridge-contacts p18, pit), on the rotary part p2 of the speed control device SC. The motor circuits through the resistance R and the by-pass around resistances R and RA may be under the control of an open-limit switch OLS and a closedlimit switch CLS.

For the door opening movement, the switch CSW is thrown to operate the motor M in the door opening direction (down position Fig. l) and with this switch closed the motor M is initially energized under the full power of the line, current flowing from line L, conductor dli, switch CSW, conductor dill, bridge-contact 4| of limit switch OLS, conductor dlZ, bridge-contact dl3 of relay RE, conductor dl4 by-passing resistances R and RA, conductor d2, switch CSW and then in series through the armature and field of motor M by way of conductors d3, d5, d5, 01, switch CSW, conductor dB, and then to line LX by conductor d1.

There is also a circuit to the motor through resistance RA, the circuit being traced from L, resistance RA, conductor d2, switch CSW, and from said switch through the motor M to line LX by the path described just above.

When the door D has moved a short way (an inch or so) from its fully closed position, cam 48 of limit switch CLS allows bridge-contacts 4'2 and 42a to close the gaps between conductors d20 and (HI and between di 2 and 0325, and bridgecontacts of OLS closing the gaps in thecircuits there at all times except when the door is in its fully open position, a third motor circuit, through the retarding resistance R is established.

' In this embodiment-of Fig. 1 this circuit raced from line L by way of bridge-contact lla of limit switch OLS, conductor (120; bridge-contact 42a of limit switch CLS,conductor d2I, resistance R, conductor d2, switch CSW and then through the armature and field ofmotor M to line LX by way of conductors d3, d4, d5, d, d6, d1, as previously described. While the motor circuit which bypasses the resistances R and RA remains established, the door opening movement and the speed of the motor M will accelerate until a predetermined speed is reached at which the speed control device SC acts. At said predetermined speed of the door opening movement the bridge contact pIB closes the gap between conductors-.dIG and (ill, causing current to flow through the coil of relay RE and causing the bridge-contact dl3 to break the circuit between conductors dl2 and dI4, thus causing resistances R and RA to act as ajretarding means on the motor M and consequently on the speed of the opening movement of the door D. Theacceleration of the door on its opening movement is thereby checked after the action of the speed control device SC as just explained. The circuit through .the coil of relay RE is traced from line L through the coil of relay RE, and conductors (ill and (U6 and bridge-contact p I 8 to line LX.

As the door D closely approaches the limit of its opening movement, the cam 41 will act to open limit switch OLS, thereby interrupting the fiow of current through the motor circuit which includes the resistance R as well as through the circuit which b-y-passes resistances R and RA,

should this circuit be not interrupted at the time 1 at bridge-contact dI3 of relay RE by the action of speed control device SC. After the motor circuits are opened at open-limit switch OLS the only current which flows through the motor is the feeble one which passesthrough the resistance RA and which acts to bia the motor in a direction to hold the door in the fully open position, as previously described.

For the door closin movement, the switch CSW is thrown to operate the motor in the reverse direction to that on the door opening movement (up position as shown in the drawings) The circuits to the motor M to and from switch CSW are the same as those previously traced except that the current from line L now flows from the switch to the motor over conductor d instead of over conductor d4 and the I return to LX being via conductors d4, d6, (11, thus reversing the direction of rotation of the motor. The rotating magnet 10 now turns in a direction oppositeto that on the opening movement, and when the acceleration of the motor M and door D reaches a predetermined speed the coil of relay RE is energized to interrupt'the circuit which by-passes resistances R and RA through the action of bridge-contact pI9 of the speed control device SC. By increasing the tension of spring pl I, the speed control device SC can be adjusted to act at a higher opening speed than the closing speed, so that the door D may be opened more quickly than it is closed.

As the door D closely approaches the limit of its closing movement the cam 48 will act to open limit switch CLS, thereby interrupting the circuit which passes through the resistance R (bridge-contact 42a of limit switch CLS opens a gap between-conductors 1120 and MI) and also the circuit which by-pa-sses the resistances R and RA (bridge-contact 42 opens a gap between conductors dI2, (Z should the latter circuit be not already interrupted at the bridge-contact dI3 of relay RE). In its fully closed position a. feeble current flow through the motor is maintained so that the motor M acts as a positive means for holding the door in its fully closed position. Said feeble current will flow from line Lby way of resistance RA, conductor d2, switch CSW and then in series through the field and armature of motor Mto line LX by way of conductor d5, d4. d6, (11, as previously described.

Continuing now thedescription of the action of the speed control device SC to bring resistance into the circuit of the motor M in reference to the embodiment shownin Fig. 2, the motor M in this embodiment i illustrated as a three-phase alternating current motor.

The retardation of the motor may be effected by electrical resistances RI, R2, R3, in theclrcuits of the motor. These three resistance are by-passed in whole or in part through the bridgecontacts of the relay R, and the energization of 'the relay -R will break circuits which by-pass the resistances RI, R2, R3, thereby bringing these resistances into action to retard the speed of motor M. The energization of the relay R is under the control of the speed control device SC. The direction of rotation of the motor M is under the control of relays OR and CR, relay OR bringing about the runnin of the motor in a direction to open the door and the relay CR to bringing about the rotation of the motor M in the direction to close the door. The operation of the relays OR and CR may be efiected through control switches OLS and CLS respectively.

The embodiment of Fig. 2 includes means for immobilizing the electrical operator in the fully open and fully closed position of the door. The immobilization may be effected in a number of ways. The current flow to the motor M may be greatly reduced or cut off entirely. In the embodiment of Fig. 2, switches OLS an'd CLS are provided for cutting off the flow of current to the motor M at or from near the open limit and the closed limit, respectively, of the door. 'These switches OLS and CLS are included in the circuits of. the relays OR and OR. The limit switches OLS and CLS may have various forms and be operated in various ways. In the embodi ment illustrated the switches OLS and CLS comprise bridge-contacts 4|, 42, mounted on levers I 43, 44, which levers are operated on to move the bridge pieces M, 42 to positions to open the cir-' cuits by cams 41, 48 on the shaft of the gear cl I, which gear and shaft move in synchronism with the door. vThe circuits from the switches OLS and CLS are traced as follows:

Circuit 0. switch OLS: Line LI, bri ge-contact 4I, conductor 50, bridge-contact 52 of relay CR. conductor 53, coil of relay OR, conductor 55, bridge-contact 5'! of control switch CS and conductor 59 back to line L2.

Circuit of limit switch CLS: Line LI, bridgecontact 42, conductor 6|, bridge-contact 62 of relay OR, conductor 63, coil of relay CR, conductor 65, hridge-ccntact 51 of controller switch CS and conductor 68 back to line L2. When turned in the opposite direction, the control .switch CS may establish the same circuit through relay .OR, and is traced as follows: Line LI; re-

sistance RI, conductor LII, bridge-contact LIZ of relay OR, conductors LI3 and LI4 to motor M. When relay R is deenergized current also passes from line Llover the by-pass circuit to, bridge-contact 75 of relay R, conductor ll, part of resistance Rl, conductor LI Lbridge-contact LII? and conductors Lid and LN. From the line L2 the flow 'of current to and from ,the motor is by Way of resistance R2, conductor L2I, bridgecontact L22 of relay OR and conductors L23 and L2 1, Also when relay OR is deenergized, current flows by way of by-pass conductor 53d, bridgecontaot 85 of relay R, conductor 8!, part or" resistance R2, and from said resistance to the motor by way of conductors L26, etc. as previously described. From line L3, the current flow to and from the motor M is traced as follows: Line L3, resistance R3, conductor L3l, bridge-contact L32 of relay OR and conductors L33 and L3 to the motor. When relay R is deenergized there is a conducting path through a circuit which bypasses the resistance traced as follows: Lt, conductor til, bridge-contact 95 of relay R, conductor t l, part of resistance R3, and from thence to the motor via conductors L3I, etc. previously described.

On the door closing movement the current flow between the motor M and the three lines LE, L2, L3, passes through the relay CR and the direction of the rotation of motor M is the reverse of that on its door opening movement. The flow is traced as follows: from Line Ll, resistance RIJ, conductor Lit, bridge-contact Lil of relay CR and conductor L3 3 to motor M. When relay R is deenergized, there is also a flow of current by-passing resistance Rl, by Way of conductor id,

bridge-contact of relay R, conductor it, part of resistance El, and then to the motor by way of conductors Lie, etc., previously described. From line L12 the current iiow is by way of resistance R2, conductor L28, bridge-contact Lt? of relay CR, and conductor L24 to motor M.

When relay resistance R is deenergized there is also a fioW through the circuit by-passing resistance R2, comprising conductor 80, bridgecontact 85 of relay R, conductor 8|, part of resistance R2, and then to motor M by Way of conductors L26, etc., previously described. From line L3, the current flow to motor M is by way of resistance R3, conductor L36, bridge-contact L3? of relay CR and conductor LI4 to motor M. When relay R is deenergized there is also a flow Icy-passing resistance R3 by way of conductor bridge contact 95 of relay R, conductor 9i, part of resistance R3, and then to motor M by Way of conductors L38, etc., previously described.

The circuits of motor M for the door closing operation, as here shown, may pass through more of the resistances RI, R2, R3 than where the motor is running in the door opening direction. This is done so that the door closes at a slower speed than that at which it is opened. B using a larger amount of resistance in the circuits when the motor M is operatin in the door closing direction, a desired differential between the opening and closing speeds of the door may be obtained.

When the door on its opening or closing movement reaches a predetermined speed, the speed control device SC operates to energize the relay R and thereby break the by-pass circuits around resistances R5, R2, R3, thereby decreasing the how f the current to the motor M and retarding its action, which retardation may be so arranged that afterreaching the predetermined speed the motor no longer accelerates th door closing or door opening movement.

The circuit through the coil of relay R is from line LI, said rela coil, conductor IOU, conductor lilI, bridge-contact pIil of speed control device SC, conductor I82 to line L2, and also from line LE, said relay coil, conductor I00, branch conductor Hi5, bridge-contact pI9 of speed control device SC, and conductor I06 to line L2. The speed control device is adjusted, as heretofore described, to close the circuit through the coil of relay R at one or the other of the bridgecontacts pill, pIii according to the speed and direction in which the motor M is rotating and when the bridgeecontacts M8 or pi9 bridge the space between conductors NH, and I02 or I05 and H16, the circuit through the coil of relay R is closed, and the relay is energizedto break the by-pass circuits around the resistances RI, R2. R3 in the circuits of motor M.

Description of operation based on the embodiment of Fig. 2

The door D being in closed position, as shown, the electric operator operates to open the door as follows: Controller switch CS is turned so that its bridge-contact it closes the gap between conductors 55 and 59, and completes a circuit through relay OR, from line LI through bridgecontact ll of limit switch OLS, conductor 50, bridge-contact E2 of relay CR, conductor 53 coil of relay 0R, conductor 55, bridge-contact 51 of controller switch CS, conductor 59, to line L2. The energization of relay OR closes the circuit to the motor M by the bridge-contacts LI2, L22, L32. Relay R is not energized at this time; its bridge-contacts 5, 85, $55 closes the circuits bypassing resistances Rl, R2, R3. Current in three phases flows to the motor M from lines LI, L2, L3, through circuits previously described; which include the by-pass circuits by way of conductors 'IIl, H and bridge-contact i5, conductors 80, BI, and bridge-contact 85, and conductors 90, 9| and bridge-contact 95. The motor M turns with its maximum opening power and starts the door opening movement through the action of pinion cID, gear cII, lever cl2, lever cI5 and link cI8. The door in opening quickly accelerates under the maximum opening power of the motor M. Meanwhile the magnetic rotor p is turning in synchronism with the motor M and door D and is exerting a torque or magnetic drag on the rotatable part p2.

Rotation of the part 122 under the drag of the rotating magnet p is opposed by the spring pIO acting on the arm p1 of part 112 which carries the bridge-contact pIB. The tension of spring I0 is so adjusted that the drag exerted by the rotating magnet 72 is insufiicient to bring the bridgecontact M8 in contact with the ends of conductors I62 and It! until a predetermined speed on the opening movement of the door is attained. When said predetermined speed is attained and the gap between the wires m2 and IDI is closed by the bridge-contact M8, the relay R is energized, current flowing from LI through the coil of relay R, conductors I00, I OI, bridge-contact m8. conductor I62 to line L2. Energization of magnet R breaks the circuit in the by-pass conductors i9, 'll, 80, SI, and 90, SI at the bridgecontacts I5, 85, 95. Current can thereafter only flow from lines LI, L2, L3 to conductors LI I, LZI, and LSI, leading to the motor M, through the intervening resistances RE, R2, R3. This diminishes the flow of current to the motor M and thereby diminishes its power, so that the door opening movement is retarded. The efiect ordi narily desired is to prevent further acceleration of the door in the opening direction, maintaining a speed during most of the remainder of the door opening movement corresponding approximately to that obtained at the time the power of the motor is diminished.

As the door closely approaches the limit of its opening movement it is usually checked and the electric operator immobilized. A number of means may be provided for this purpose. The current of the motor may be much reduced leaving it feebly energized, or the circuit may be broken. As here shown, means are provided for breaking the circuit to the motor M. This means is the switch OLS previously referred to. Cam 4'! moves in synchronism with the door and also the motor M, and as the door approaches close to its limit of opening movement, the cam turns the lever 43 whichmoves the bridge-contact M to break the circuit between the lines LI and 50. This in turn deenergizes the relay OR allowing the plunger which carries bridge-contacts LI2, L22, L32 to drop,breaking the circuits from the lines LI, L2, L3 to the motor.

A door check IIO may also be provided, the

action of which is to check the momentum of the door near its limits of opening and closing the. current now flows to the motor M from the lines LI, L2, L3, in such a way as to cause it to turn in a reverse direction from that previously described, that is, the motor now rotates in a direction to operate on the connection C to close the door. Relay R not being energized at this time its bridge contacts I5, 85, 95 close the circuits which by-pass the resistances RI, R2, R3. Current in three phases now. flows to motor M from lines LI, L2, L3 through circuits previously described, which circuits include the by-pass circuits by way of conductors I0, II and bridgecontact I5, conductors 80, 8| and bridge-contact 85, and conductors 90, 9| and bridge-contact 95.

The motor M turns with its maximum closing power and starts the door closing movement through the connections C previously described. The door in closing, quickly acceleratesunder the maximum closing power of the motor M, which power, however, in the embodiment shown, may be less than the full opening power of the motor on the door opening movement, as previously described, Magnetic rotor p of the speed control device SC is rotating in synchronism with the motor M. The tension of the spring pH of the speed control device SC is so adjusted that the drag ex- .erted by magnetimrotor p on rotary part 122 is insufficient to bring the bridge-contact p19 into contact with the terminals of conductors I05, I06

.until a predetermined speed of the door on its closing movement is attained. This predetermined speed may be different from that at which the relay R goes into action on the door opening movement, and this diflerential may be taken care of through adjustment of the springs pl0,

I pl I. When the predetermined speed is attained R, conductors I00, I05, bridge-contact pI3, and

conductor I06 to line L2. Energization of relay R results in breaking the circuits which by-pass portions of the resistances RI, R2, R3, and with these resistances in the circuit of motor M its power is reduced and the door closing movement retarded. The effect usually arranged is that the door closing movement no longer accelerates, but continues at a fairly even rate until .the door reaches a positionclose to its closed position. As the door closely approaches the limit of its closing movement, the limit switch CLS goes into action, breaking the circuit through the coil of relayCR through the action of cam 48 and lever 44 on the bridge-contact 42, opening the gap between the conductors LI and 6|. When the coil of relay CR is deenergized, its plunger which carries the bridge-contacts LII, L21, L31 drops, thereby breaking the circuit from the lines LI, L2, L3 to the motor M. The momentum of the door may be checked by the door check I I0 and the door comes to a stop in its fully closed position. It is biased or held there in various way v In the present embodiment, the crank pin cI3 is close enough to one of its dead center positions. that a small counterweight CW on the link cl 2 is sufiicientto keep the doors in the closed position. The doors may be manually opened with reasonable ease by pulling directly on the door.

If, on either the opening or closing movement of the door, such movement is checked, as by the door meeting an obstruction, or being obstructed manually by a person, the movement of the door and consequently that of the motor M would be slowed down, and this would result in either the spring pIIl or pH of the speed control device SC having greater force than the torque between the magnet 10 and the part p2, and the circuits at one or the other of bridge-contacts pl8, pl9 will be broken, thereby deenergizing the relay R, allowing the plunger to drop, and the bridge-contacts i5, 85, complete the by-pass circuits around the resistances RI, R2, R3, so that upon resumption of the movement of the door in either direction from whatever intermediate position it is at, the full closing or opening power of the motor M is again applied and continues to act, accelerating the door movement, until a speed is reached at which the relay R is again energized through the action of the speed control device SC.

Description of operation based on embodiment illustrated in Fig. 1

Door D being in closed position, control switch CSW is-thrown to energize the motor M in the door opening direction (down position Fig- 1). The motor starts to move under the full opening power of the line, 'current flowing from line L, conductors d9, dI0, bridge-contact 4I of limit switch OLS, conductor dIZ, bridge-contact dI3 of relay RE, conductor dI4 Joy-passing resistances R and RA, conductor d2, switch CSW and then in series through the armature and field .of the motor M by way of conductors d3, d4, d5, 11, switch CSW, conductor dB and then to line LX by con-' ductor d1. The motor M, receiving full current, the door opening movement accelerates rapidly. When a predetermined speed of opening has been reached, the drag of magnet 10 of speed control device SC on part 112 is sufficient to overcome the resistance of spring pm, a circuit is completed through the coil of relay RE by bridge-contact plB, and the circuit which by-passes the resistances R and RA is interrupted at the bridge-contact (M3. The current flow through the coil of relay RE is from line L through the coil, conductor dli, bridge-contact pit of speed control device SC, conductor dlt to line LX. After the cir cuit which by-passes resistances R and RA was established, another circuit through the resistance R was established when the door had moved an inch or so, so that when the aforesaid by-pass circuit is interrupted, the current flow to the motor M is through the resistance R as well as resistance RA. The eifect of the resistances R and RA is to retard the motor, the amount of retardation being usually contrived to prevent further acceleration of the motor on the door opening movement. The motor circuit through resistance R is traced as follows: Line L, bridge-contact tic of limit switch OLS, conductor 112d, bridge-control rice or" limit switch CLS, conductor diii, resistance R, conductor d2, switch CSW, conductor d3, dd, 015, (1, switch CSW and conductors (it and dl to line LX. The circuit through resistance RA is from line L, resistance RA, conductor d2, switch CSVT and from the switch through the motor to line LX over the conductors previously described.

Should the door opening movement be retarded or momentarily stopped by an extraneous object, or its direction of movement changed before the door D reaches its fully open position, the resumption of the opening movement, or movement in the reverse (closing) direction, will be under the full power of motor M at whatever position of the door the resumption of the door movement or the reversal of the door movement begins. This automatically occurs because when the door movement is retarded, or is reversed, the speed of motor M falls, and consequently the drag of magnet p of speed control device SC on part p2 diminishes, whereupon spring pic acts on arm pl to move the bridge-contact pit to open a gap between conductors dlfi and dll' and thus interrupt the flow of current through the coil of relay RE. Thereupon bridge-contact diS reestablishes the circuit which by-passes resistances B and RA and current flows to the motor M under the full power of the line.

As the door D closely approaches the limit of its opening movement, the cam 4? acts on limit switch OLS to open a gap between conductors all 3 and M2 at bridge contact ii and between line L and conductor (Z at bridge-contact Ma thus interrupting the circuit previously traced which passes through resistance R, as well as the circuit which by-passes resistances R and RA, should the latter circuit then not be interrupted at the bridge-contact tilt of relay RE.

Shortly after the limit switch OLS acts the door comes to a stop. An abutment or stop A may be provided at the open limit of the door. In this embodiment a feeble current continues to flow to the motor M through the resistance RA. The circuit as previously described is from line L, resistance BA, conductor d2 to switch CSW, and from there through the field and armature of motor M to line LX by conductors d3, dd, (15, d, d6, d1. The feeble current acts on the motor M to bias it in the door opening direction to hold the door against the stop A.

Means for cushioning the impact of the door D with the stop may be provided. The door con nections C provide in effect such a means. The pin on gear 02 to which link 03 is connected approaches at this time a. dead center position and consequently the door is moving very slowly as it meets the abutment A.

To close door D, the switch CSW is thrown in a direction to admit the current to the motor M to cause the flow to be reversed and the motor to turn in the reverse direction to that on the door opening movement. On the drawings this is illustrated by the up position of switch CSW. Current flows to the motor from line L to switch CSW over the circuits previously traced, from switch CSW to the motor and then to line LX, over the path previously traced except that current news from conductor d2 through the switch to conductor 035, instead of to conductor old, as on the door opening movement. At this time relay RE is not energized and full current flows to the motor, so that the speed of the motor M and or" the door D accelerates under the full power of the motor. After the first inch or so or" the door movement, limit switch OLS acts to close the motor circuit, at the bridge-contacts ii and did, which includes resistance R as previously described. When the door attains a speed at which the drag of magnet p on part p2 of speed control device SC is great enough to move the part p2 against the force of spring bridge contact pi closes the circuit through coil of relay RE, whereupon said coil is energized and the bridge-contact (N3 of relay RE opens a gap between conductors (M2 and dicwhich bypass the resistances R and RA. Thereafter current to the motor M passes through the resistances R and and the speed of the motor and that of the door D is retarded as previously described. The door closing movement may be made slower than the door opening movement by decreasing the tension of spring pl! so that the acceleration of the door speed is less on the closing movement than on the opening movement at the time the speed control device SC acts to break the circuit which by-passes the resistances R and RA, this breaking of the by-pass circuit being effected by the relay RE in the manner previously described.

Should the door meet an obstruction on the closing movement, or the direction of its movement be reversed, the consequent momentary stopping or slowing of the motor M will cause speed control device SC to act to deenergize the coil of relay BE in the manner previously described, and thereby establish the motor circuit which by-passes resistances R and RA. Thereupon motor M will be energized with full power and rapidly accelerate the door movement in the door closing direction, or in the reverse direction, from whatever position the resumption of closing movement, or the movement in the reverse direction, begins.

As the door approaches the limit of its closing movement, cam 48 acts on bridge-contacts s2 and 42a to open a gap in the motor circuit which by-passes the resistances R and RA and also in the motor circuit which passes through resistance R, similar to the action on the opening movement. The door D comes to a stop against the door jamb or against an abutment and its stopping may be cushioned by suitable means. in the illustrated embodiment the connection C acts as a cushioning means. The pin on gear 02 to which link 03 is connected approaches its dead center position as the door closely approaches it closed limit, so that the door is moving very slowly as it reaches its closed limit.

A small current continues to flow to motor M through'the resistance RA, and the motor M remains energized to moderately oppose the move- .so that said motor, irrespective of the position of the door at an initiation, resumption or reversal of its opening or closing movements, operates with its full power, undiminlshed by said retarding means, to rapidly accelerate the door opening and closing movement until the motor speed reaches said predetermined speed at which the retarding means is again brought into action.

5. An electric operator for opening and closing doors and the like, according to claim 4, further including limit switches for interrupting the motor circuits through said resistance and the by pass at each limit of the operator action.

door-equipment from closed to open position, and-vice versa, much faster than the predetermined time interval, retarding means operable to limit acceleration of the motor-speedafter a predetermined motor-speed has been attained, and a control device responsive to the speed of the motor, operable at said predetermined motor speed to bring into action said retarding means, and below said predetermined motor speed to take out of action said retarding means, so that said motor, irrespective of the position of the door at an initiation, resumption or reversal of its openincluding limit switches for interrupting the motor circuit at each limit of the operator action.

4. An electric operator for opening and closing doors in predetermined time-intervals of opening and closing, an extra powered electric motor door operating means actuated by the motor, said motor being capable of moving the load represented by the door and the door-equipment from closed to open position, and vice versa, much faster than therpredetermined time interval, a motor circuit including a resistance actable as a retardin means ior limiting acceleration of the motor speed after a predetermined motor speed has been attained, and a circuit by-passing said resistance in which condition the. acceleration of the motor is not retarded by said resistance, a relay normally' closing said by-pass circuit, and'a control device responsive to the speed of the motor, operable at said predetermined motor speed to actu ate said relay. to open said by-pass circuit, thereby causing said resistance to act to retard the motor and limit its'acceleration, and-operable to again close said by-pass circuit when the speed of the motor falls below said predetermined speed,

6. An electric operator for opening and closing doors and the like, according to claim 4, further including a relatively high resistance motor circuit acting to feebly energize the motor at a limit of the operator action for exerting a positive force tending to hold the operator at its limit position.

7. An electric operator for opening and closing doors in predetermined time intervals of opening and closing, comprising an extra-powered reversible electric motor, door operating means actuated by the motor, said motor being capable of moving the load represented by the door and door equipment from closed to open position, and

vice versa, much faster than the predetermined time interval, retarding means operable to limit acceleration of the motor speed in eitherdirection aftera predetermined motor speed has been attained, and a control device responsive to the speed of the motor in either direction, operable at said predetermined motor speed to bring into action said retarding means, and below said predetermined motor speed to take out of action said retarding means, so that said motor, irrespective of the position of the door, at an initiation, resumption or reversal of its opening and closing movements, operates with full power, undiminished by said retarding means, to rapidly accelerate the door opening or closing movement until the motor speed reaches said predetermined speed at which the retarding means is again brought into action.

8. An electric operator for opening 'and closin doors in predetermined time intervals of opening andclosing, according to claim 7, wherein the predetermined time intervals for closing and opening the door are different, and wherein said control device comprises means for effecting differential action thereof on the door opening and door closing movements.

9. An electric operator for opening and closing doors in predetermined time intervals of opening and closing, according to claim 7, wherein the predetermined time interval for closing the door on the door-opening movement.

JAMES H. BANKS. HARRY R, moans.

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