US3080947A

US3080947A - Elevator controls

Info

Publication number: US3080947A
Application number: US86666A
Authority: US
Inventors: Dale L Stone
Original assignee: Toledo Scale Corp
Current assignee: Toledo Scale Corp
Priority date: 1961-02-02
Filing date: 1961-02-02
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12

Description

March 12, 1963 Filed Feb. 2, 1961 D. L. STONE ELEVATOR CONTROLS 2 Sheets-Sheet 1 no @44, g

ATTORNEYS March l2, 1963 D. L. STONE 3,080,947

ELEVATOR CONTROLS Filed Feb. 2, 1961 2 sheets-sheet 2

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lo, INVENToR; i DALE L` STONE JJ- BY #PMMA v-J/Juw ATTORNEYS United States Paten-t Office 3,080,947 Patented Mar. 12, 1963 3,080,947 ELEVATOR CONTROLS Dale L. Stone, Toledo, hio,'assignor to Toledo Scale Corporation, Toledo, Ohio, a corporation of Ohio Filed Feb. 2, 1961, Ser. No. 86,666 ZQCIairns. (Cl. 187-52) This invention relates to elevator controlsnimore particularly to controls for the starting of elevator cars and the Operation @teler/atar. doors Y Heretofore it-has been common practice to control the starting of elevator cars in accordance with, the operation of the doors of` those cars whereby upon completion of the closing of the doors and incidental tothe latching of the doors in the closedposition the car is automatically started awayjfrornthe landing to respond to the registered calls. In those systems where the cars have been operated with powerfdrive'n doors door protective devices have been includedin order to avoid injuring passengers by striking them with the doors, These door protective devices become aparticularly signicant where the cars. are operated without attendants and the door closing operations are` initiated a given interval after or upon completion of a` given function following a door opening operation. It has been common practice to provide the leading edge of the door with some form of device which senses obstructions in the closing path of the door and` either stops the door or altersK its operation as by reversing it to a fully open position.' Frequently such door edge protectiye devices have taken the form, of mechanically ac-v tuated switches which lead the door slightly and are operated upon encountering an obstruction.' Another door protective device often employed either alone or in conjunction with the door edge protective devicesV includes a source of radiant energy and a radiant energy detector arranged S0 that the Source projects, the energy along the door closing path and the detector senses the changes in the transmission of the particular type of energy utilized as might be caused by an obstruction in or adjacent the door closing path.

Difculty has been encountered with radiant energy sensing door protective devices in those situations where the ambient conditions change sufficiently so that the transmission characteristics for the energy are altered to an extent falsely indicating an obstruction in the path. Such changes in` ambient conditions occur where dense smoke is present which obstructs a visible beam of light projected across a doorway thereby darkening the light sensitive'cell normally irradiated by such beam even though no door obstruction is present to falsely indicate the presence of an obstruction and prevent the closing of the doors. Under such circumstances the car having its doors open is held at a landing and cannot be started. l' The present invention has for its principal object the avoidance of the aforenoted difficulty by sensing the change in ambient conditions and indicating that change to the door protective devices whereby those devices are conditioned to avoid giving false indications of obstructions.

Another object is to avoid the lookup of an elevator car by radiant energy sensitive protective devices controlling car operation when the transmission of the energy is altered.

A third object is to alter the stopping interval of a car at a landing in response to a change in ambient conditions in the closing path of the car door.

A fourth object is to expedite the departure of a car when it stops at a landing having predetermined ambient conditions in the vicinity of the entry to the car.

A fifth object is to alter the door controls responsive to operation from Within the car in response to predetermined ambient conditions in the vicinity of the car entry. f

Another object is todirect the operation of an elevator car in response to the ambient conditions in itsV vicinity and particularly to facilitate the expeditious transfer of passengers from an area in which adverse ambient conditions prevail to an exit.

In accordance with the above objects one feature of the invention comprises combining a door control including radiant energy generating means, means responsive to changes in energy transmission in the vicinity of the door to sense obstructions in aA closing path of the doorr and means to control door operations appropriately in4 response to those obstructions with a second radiant energy generating means arranged to sense the ambient conditions in the vicinity of the car entry without having the energy transmission characteristics altered by the presence of obstructions in the closing path of the door.

yOne such system utilizes a visible beam of light projected across a doorway adjacent the closing path of the door and irradiating a photosensitive detector. When blocked from the light beam by an obstruction, the detector alters the door controls as by stopping or preventing closing movement. A second beam of light is also projected over a path generally corresponding to the path of the first beam and in the vicinity of the door to a second photosensitive detector, this second beam being so oriented that it is not interrupted by obstructions in the car door? way but will be interrupted if the atmosphere adjacent the car entry is fouled by smoke, dust or -vapors which would block the first door protective beam. vUpon sensing the presence of such ambient conditions, the second detector alters the door protection controls to negate the false indication of an obstruction. Such alteration of the controls can include means to permit the closing of the door without regard to indications of obstruction by the radiant energy detector, means to alter the interval the door normally remains open, means to enable the manual control of the doors as by means of pushbuttons within the elevator cab, and means t'o set the car to run toward a building exit. T hesc door protection alterations can be eifected while maintaining other door protection means effective. Thus door edge protection can remain effective to stop or reverser a car` door in case an obstruction approaches the leading edge of the door during the closing operation.

While the discussion which follows is directed principally to photoelectric sensing of visible light and is concerned particularly with sensing ambient conditions of dense smoke `.adjacent to the `car doorway which might normally produce a false indication of a door obstruction, it is to be understood that the principles of this invention involving the sensing of disrupting changes in the ambient conditions adjacent a car entry are applicable to other door obstruction sensing systems. Included among those other systems are the type responsive to electromagnetic energy of the type normally considered radio waves, radiant energy outside the Visible range including infrared and ultraviolet, or ultrasonic energy. Each of these forms of energy can be radiated along a confined path which has its transmission characteristics altered by the presence of dust particles, steam, extraneous sources of energy or adverse humidity conditions in the path and can be combined with a complementary energy detector which senses variations in .the energy level transmitted.

The invention is also applicable to other forms of detectors such as disclosed in Lubkin Patent 1,982,442 of November 27, 1934, in which a tuned oscillator is detuned by obstructions adjacent the door closing path to operate .door control circuits and can be detuned by high humidity conditions. In such systems a second oscillator insensitive to obstructions but responsive to the humidity conditions detuning the first oscillator can be employed to negate the false indications of an obstruction or to otherwise alter the systems operation as contemplated by this invention.

The invention together with the above and -additional objects and features thereof Will be better appreciated from a consideration of the following detailed disclosure when read with reference to the accompanying drawings Where- FIG. I is a diagrammatic representation of an elevator car illustrating a radiant energy door protection device and an ambient condition sensing device of this invention;

FIG. II is an across the line diagram of a portion of the door control circuits for the car illustrated in FIG. I according to this invention;

FIG. IH is an across the line diagram of certain of the door control circuits for a car utilizing this invention;

FIG. IV is an across the line diagram of the car starting circuits, typical of the type which might be employed with this invention;

FIG. V is an across the line diagram of portions of the car direction and reversal control circuits illustrating one adjunct of this invention for facilitating evacuation of an area having a fouled atmosphere; land FIG. VI is an alternate for-m of control for the door protective functions which can be substituted for FIG. II to provide certain operating characteristics.

In illustrating the invention a single car having a variable voltage D.C. lifting motor is discussed. However, it is to be understood that the invention is applicable to elevator systems of one or a plurality of cars and that any form of lifting motor can be utilized. Further, while the means for operating the doors has not been disclosed in detail, and the system has been'applied to doors operated by direct current motors, it is to be understood that many alternative forms of door operators might also be utilized with the present invention to advantage. For example, pneumatic or hydraulic drives for the door operators are known. Alternating current electric motors may be utilized or a door can be driven in the closing direction by either spring force or a gravity actuated mechanism. In each of the systems utilizing equipment of the `above type the present invention will function to initiate and control door closing and starting of the elevator car.

Before describing the invention the system of notation utilized in the drawings will be set forth. The diagrams are presented in across the line form. In this form the actuating coils for relays and switches are not physically coupled to the contacts which they actuate and may appear on different sheets of the drawings in proximity to the circuits and elements they control thereby facilitating an understanding of the electrical circuitry involved. In order to correlate the actuating coils with their contacts the diagrams have been divided into horizontal bands or zones which are numbered in the right-hand margin. The symbols designating the actuating coils are positioned in the margin adjacent the zone numbers in which those coils are located. The extreme right hand portion of this index contains the numbers of the zones in which the contacts operated by the actuating coils will be found. Zone numbers identifying the location of back or break contacts, those which are closed when the coil is deenergized yand are opened When the coil is energized, are underlined to distinguish them from the zone numbers identifying front or make contacts, those contacts which are normally opened when the actuating coil is deenergized and are closed vby energization of that coil.

Only those portions of the elevator control circuits necessary for an understanding of the present invention are illustrated. Therefore, no lifting motor control circuits, car call or landing call circuits, car stopping circuits, car leveling circuits, or dispatching circuits are disclosed although it is to be appreciated that conventional circuits and equipment of this type are applied to the elevator or elevators embodying this invention. The relays and switches having actuating coils in the illustrated diagrams are tabulated below in the alphabetical order of their symbols together with a short title and the line location 5 of the actuating coil.

Symbol Name Line AS Start 24 CL Door Close 3l C Car Start 46 First Emergency Door Close.-- 68 Second Emergency Door Close 70 Third Emergency Door Close and 73

Door Control

13 and 64 Door Control Time 28 Emergency Expedite Timer 66 Main Landing Reversal 5l Door Open 27 Door Open Control 2G Car Photocell 10 and 61 Smoke Photocell l1 and 62 Car Button Reset 53 Direction Throwover Up-. 52

Direction Tbrowover Dow 53 Minimum Start Time..." 41

Standing Time Saver Time-. 21

Standing Time Saver 22 In addition to those switches and relays tabulated above a number of contacts are shown which are actuated by coils other than those illustrated in the diagrams. 'I'hose contacts are set forth below with their symbols arranged in alphabetical order and their relay and switch designations.

Name

Auxiliary Main Switch. Brake. a Door Glose Buzzer Time. Down Dispatch.

Up Dispatch.

Down Direction Control.

Gate.

High Call Reversal. Down Leveling.

M-G Set Starting. Up Leveling. Leveling Zone.

Lower Main Landing. Upper Main Landing. Car Photo Relay. Smoke Photo Relay.

Retiring Cam.

UL Up Direction Control.

A typical elevator car is diagrammatically illustrated in FIG. I. According to usual practice, the car is guided -by hatchway rails 71 running vertically along the sides of the hatchway in which the car travels and engaging guide shoes 72 attached to the elevator car. The car is supported by cables 73 running up the hatchway to drive equipment (not shown). The car is also equipped with a door operating mechanism 74 that includes a pivoted lever 7S connected through a link 76 to the irst door 77 and through a second link 78 to a second door 79. Since the distance from the fulcrum of lever 75 to links 76 and 7S is different, the travel of doors 77 and 79 is also different. This allows the doors to overlap each other in open position and close in slightly overlapping position to close the entire door opening of the elevator car. The door control mechanism for the car also includes a light source 81 that projects a vbeam of light indicated by a dotted line 82 -to a photoelectric cell 83 mounted on the frame of the car. The photoelectric cell is connected into the control system of the elevator so that under ordinary circumstances the doors cannot be closed unless the light lbeam 82 is uninterrupted. Thus if any passenger or other obstruction is in the doorway of the elevator, the doors will not attempt to close.

While a radiant energy detector such as a photoelectric beam and photocell combination is frequently ernployed as the only means of sensing obstructions in the closing path of a door, it is advantageous to employ supplemental means particularly where a light beam is utilized 75 and senses only a portion of the area in which an obspade-1.7i

struction can be placed. One supplemental door protection device is a safety shoe 84 on the leading edge of the leading door along virtually its entire vertical length. When displaced by encountering an obstruction, the shoe 84 actuates a switch 85 seen in FIGS. Il and VI at 12 and 63, respectively, to prevent initiation of the door closing motion or on a partially closed door to alter the driving force tending to close the door whereby the door is retarded, stopped, or reversed to avoid injury to the obstruction.

Abnormal ambient conditions in the vicinity of the entry to the elevator such `as caused by the presence of dense smoke, or steam as might4 result from a lire or a broken steam pipe, can foul the atmosphere in the car entry and reduce the transmission of light from source 81 to photocell 83 to such an extent as to indicate an obstruction in the closingy path of the door even Iwhen no such. obstruction is present and can lock up the operation of the systems so that the car cannot depart from the, landing. In the case of a fire this can be quite dangerous since the elevators then serve as a trap rather than a means `of, escape.

`In order to avoid this diiculty, means are provided to sense this abnormal transmission characteristic in the atmosphere. One such `detection means is shown in FIG. I adjacent the top of the doorway and above the area which is ordinarily traversed by obstructions in the doorway. It comprises a light source 86 which generally can correspond to the source 181 and .projects a beam 87 onto a photoeleetric cell 88 corresponding to the photocell 8-3 located on the opposite side of the doorway. Advantageously, the [light source 86 and cell S8 can be mounted on the car frame in the same manner as the light source 81 and photocell 83. Where the length of the light beam S7 corresponds to the ylength of beam 82 identical elements can be employed in the two systems. However, it is to be appreciated that such similarity of elements is not essential to the invention and that the orientation of the source and detection means can be altered to use either a shorter or a longer beam of light and to position the elements so that the ambient condition detector is completely clear of the normal path of any object which might traverse the passageway as by being mounted in an indentation slightly above or aligned with the upper limit of the opening to the car.

Each of the photoelectric cel-

ls

83 and 88 feed signals to suitable amplifiers and relays PCC and PCM respectively, each having contacts in the controlling circuits for the elevator car. These amplifiers and relays are not shown since they are conventional in nature and of types well known in the art.

One icontrol circuit suitable for normally providing the door protection functions and in addition automatically expediting the 'door operations when ambient conditions reduce the radiant ener-gy transmission characteristics in the vicinity of the elevator door is shown in FIG. II. It comprises a pair of main leads P and Y supplied from a suitable source of alternating current. A car photocell relay PC is connected across these leads in series with a front contact PCC which responds to the interruption of irradiation of photocell 83 by light beam S2 by opening contact PCC to deenergize relay PC. Smoke or other abnormal conditions are indicated by deenergizing smoke photocell relay PM at 11 through back contact DCE3 and front contact PCM which is closed when light transmission is normal and is responsive to reductions in the irradiation of photocell SS by light beam 87 to open and break the energizing circuit.

Door control relay DO at 113 is controlled by several alternative circuits such that the completion of any one of those circuits prevents a door closing operation or in the alternative where a door closing operation has been initiated may either institute a door opening operation or merely alter the closing operation as by removing energization on the ldoor operator motor tending to close that door without reversing the motor to open the.door, wheree by the 'door will be maintained in its partially closed` position. Relay DO is energized when the safe edge switch.

8S actuated by the safe edge s'noe 84 on the leading edge of door 79 is operated so that contact 85 is closed andv door operation is altered when an obstruction displaces that shoe with-respect to the door. At 13 a series circuit is shown consisting of a front contact of the relay PM which is closed so -long as the ambient-conditions provide normal light transmission characteristics and relay PM isV energized. A back contact ofV relay PC which is open except when an object is in the doorway to interrupt the` beam 82 and ldeenergizerelay PC. Limit switchV 89 is closed while the door is open and is opened as the door` approaches the fully closed position to render the photoelectrically responsive contacts ineffective. Cutout switch 91 can be opened when it is desired to eliminate the photoelectric control of door operation. A door open switch 92 operable from the operating panel within the car is shown at line 14 and is arranged such that the closing of that switch energizes the door control relayagain to close in the energizing circuit of smoke photo.

relay PM. This is accomplished through the closing of back contact PM in conjunction with door closed relay contact CL at 15 to initiate the energization of relay DCE3 which thereafter is maintained energized through its contact at lline 16 around the aforenoted PM contact. When thus energized, DOES opens its back contact at 'line 11 toprevent the reenergization of relay PM even thoughA` PCM is closed. As the door completes its closing operation and door closing relay CL is dropped out, relay DCESV is reset and the circuit for relay PM thereby renderedv effective again.

FIG. III illustrates th-e door timing, door opening, door closing and some of the car starting circuits which cooperate with the 'circuits of FIG. II. The elements of FIG. III are supplied from a suitable source of alternating current through the leads P and Y and in certain instances may be supplied from the same source as those leads in FIG. Il. In the system chosen to illustrate the present invention door timing normally is accomplished by two timers operating in sequence. The irst of these timers TRL at 21 measures a time interval through its energization by the closure of contact TRLA. In normal operation the standing time saver timer TRL measures an interval from the initiation of the door opening operation until a load transfer is detected at which time its operation tis terminated. This control of the timer is afforded by standing time saver relay TRLA at 22 which is energized to initiate the timing interval as the elevator car has its door opening operation initiated while it is leveling into the landing as indicated by front contact OPS of door open control relay and contact BK of a brake relay both of which are closed at this time at line 22. Once the car has stopped the brake relay is released and upon completion of the door opening operation door opening relay OPS is deenergized, thereby opening both of contacts BK and OPS at 22. A seal circuit is maintained for relay TRLA, so long as no load transfer is sensed, until the end of the timer interval measured by standing time saver timer TRL. This seal circuit appears at 23 and comprises front contact TRLA, back contact TRL of the timer which is not opened until the timer has timed out, car photocell relay tact at 23 thereby disabling the seal circuit which cannot be again reestablished inasmuch as the contacts BK and OPS are open. TRLA also opens its contact at line 21 to terminate the timing of relay TRL. Similarly if the ambient conditions are such as to prevent the reliable transmission of light across the doorway contact PM at 23 will be opened and relay TRLA Will be deenergized to deenergize timer TRL.

Start relay AS at 24 enables the car to be started through the car starting circuit of relay CS as will be discussed with respect to FIG. IV. Start relay AS is energized when a car is operating at loors intermediate the terminal iioors inasmuch as lower main landing relay MG (not shown) will be deenergized at this time so that its back contact MG at 24 is closed and upper main landing relay MC1 Will also be deenergized so that its back contact MG1 in series with contact MG will be closed. A car having its generator driving motor energized for operation as indicated by closed contact LSA of M-G set starting relay LSA (not shown) will have its start relay energized even while standing at the main landings if smoke photocell relay PM is deenergized since back contact PM in series with contact LSA will be closed at 25.

Door open control relay OPS and door open relay OP at 26 and 27 control the power supplied to the door operating mechanism during an opening operation. In one arrangement the relay OP is energized during the interval the door operating motor is energized to drive the door in an opening direction and is deenergized at other times. Relay CS at 46 is dropped out shortly after car starting has been initiated. This is caused by the energizing of TR at 41 through closure of leveling relay contact L3 at 42. Leveling relay L3 remains energized while the car runs and until it approaches within a given distance from level with a landing, e.g. three inches therefrom. As the car approaches the landing contact CS at 29 is open; hence door close relay CL at 31 is deenergized to close its contact at 26. Since door operation is initiated as a car -is slowing to stop at a landing and has entered the leveling zone, up and down leveling relays LU and LD (not shown) both of which are energized as the car is close to the iinal landing position e.g., six inches from the landing, close contacts LU and LD at 26 to partially complete the circuit for the energizing of relays OP and OPS. Retiring cam contact RC at 26 is also closed inasmuch as the retiring cam relay (not shown) is deenergized approximately when the car enters the leveling zone of the oor for which the car is stopping. The circuit for OPS is completed through a limit switch 90 of the door operator circuit which is closed while the door is closed and is opened when the door reaches a position closely adjacent the full open position, for example, l inch from the full open position, and through a cam contact 93 which is closed in response to the operation of the retiring cam in unlocking the hatchway doors to permit them to be opened during the stop of the elevator. With OPS energized at the initiation of the nal portion of the stopping operation for a car, door opening relay OP is conditioned for operation through door control time relay DT at 28 which is energized by closure of contact OPS at 28. DT closes its contact at line 27 to enable the energization of relay OP through the circuit of contacts LU, LD, CL and RC at 26 and contact DT at 27 and 93 between leads P and Y. As the door approaches its fully opened position, the relay OPS is deenergized by the opening of limit switch 90. This opens the circuit energizing timer DT at 28 permitting that timer to begin its time out interval. Upon expiration of that interval of the order of a few tenths of a second but sufficient to insure that the door is fully opened and -that it will not rebound from the nal position, timer DT drops its armature to open its contact at line 27 thereby deenergizing the relay OP and deenergizing the door opening circuit for the door operator.

Door close relay CL at 31 is energized throughout a door closing operation and controls the door operator circuitto energize it for closing. In the example a buzzer l is sounded immediately prior to the initiation of the door closing operation and accordingly a buzzer time relay BZT (not shown) is dropped out as a prerequisite to the initiation of such closing. In this example the buzzer sounds during the drop out interval and upon completion of that drop out interval back contact BZT at line `29 is closed. Assuming that a car start signal has been issued at this time so that car start relay CS is energized to close its contact at 29, door time relay DT is energized provided a door opening signal has not been issued to energize relay OPS and open back contact OPS at 29. DT is energized through the circuit from lead P contacts BZT, CS, and contact OPS to lead Y. Upon euergization of door timer relay DT, its contact at line 31 is closed and provided the door control relay DO is not energized and the door open relay OP is not energized a circuit is completed for door close relay CL from lead P through contacts BZT and CS at 29, and OP, DO and DT at 31 to lead Y. CL then closes contacts in the door motor circuit (not shown) to cause the door to be driven in a closing direction.

FIG. IV shows the second timer and car starting circuits for the car both of which are supplied from suitable sources of direct current connected across the leads R and B. Minimum start time relay TR at 41 measures the inal portion of the delay interval prior to the initiation of a car starting operation as its dropout interval. The

dropout of the relay closes a contact in the car start circuit at 48. Timer TR can begin its timing operation only if standing timer saver relay TRLA is deenergized to open its contact at 41. As indicated above, this means that the timing interval of TR can be initiated only after TRL has completed its timing or a load transfer is completed or abnormal ambient condition has been sensed. Minimum start relay TR is responsive to other operating functions. It is energized as the car begins its run and is maintained as it comes into the oor by the third leveling zone relay L3 (not shown). Relay L3 is deenergized as a car approaches to within three inches of the landing in the example and at that time opens contact L3 at 42. Timer TR is maintained energized while the doors are opening through contact OP of the door open relay at 43. This contact remains closed until the doors are fully opened. Door control relay DO will also maintain timer TR energized while it is energized, thereby requiring that the door closing conditions be reestablished to drop out contact DO at 44 before the TR timing interval can be initiated.

Car start relay CS at 46 initiates the car starting sequence and the door closing sequence. This circuit is arranged so that the car can be started and the closing of the doors can be initiated only when conditions which are safe for such operations prevail. Further, these circuits are responsive to the dispatching operations of the system, the details of which are not shown here. A circuit must be completed between lead R and lead as a prerequisite to starting of a car and closing of a car door. At floors other than the main landings, the relay AS at 24 is energized to close its contact at 44 and complete a circuit from lead R to lead 95. However at the main landings dispatching circuits are required. A car at the lower main landing has its MG relay energized to open contact MG at 24 and deenergize the AS relay. When that car is issued an up dispatch signal its CUD relay (not shown) is energized to close contact CUD at 43 thereby completing the circuit from R to 95. Similarly a car at the upper main landing has its MGI relay energized to open contact MGI at 24 and deenergize relay AS and when that car is given a down dispatch signal by energizing its down dispatch relay CDD (not shown) contact CDD at line 46 is closed to complete the circuit between R and 95. Gate relay (not shown) has a contact GA at 45 which is closed to enable the restarting of a car which stops on an emergency basis as it is coming into one of the main landings, thereby enabling the running of the cars during the period in which the car` is not level with one ofthe main landingsV yet is close enough to voperate its MG or MGI relay so that the AS relay has been deenergized.

Appropriate `conditions for safely closing the car doors and starting the car are indicated by closed back contacts of relays TRLA, DO and OP at 46. The remainder of the circuit can be energized by the timing out of minimum start time relay TR to close its back contact at 48 or by the deenergization of smoke photocell relay -PM while the car is stoppedl at a landing through the circuit including back contact BK of the brake relay, deenergized when the brake is set, back contact PM and back contact AM of an auxiliary main switch which is energized when the car is set to run. Once the car starting circuit is established it is sealed through the auxiliary main switch by contact CS at y47. As the car running circuits (not shown) are established by CS and the car runs, CS is dropped by opening contacts AM and TR.

In normal operation, a car arrives at a landing intermediate the main landings for which a call is registered and. as it comes into proximity with that landing, closes contacts LU and LD at 26 to complete a circuit for relay OPS, which in turn energizes relay DT to close its contact at line 27 and energize door open relay OP. The doors, of the car therefore begin to open. While the car is leveling into the door, contacts BK and OPS at 22 are closed -to energize standing time saver relay TRLA. This initiates the timing of standing time saver timer TRL by closing contact TRLA at 21, establishes through contact TRLA at 23 a sealcircuit at 23, maintains through contact TRLA at 41 minimum start time relay TR which was energized by the closed door opening contact OP during the door opening operation, and opens the car starting circuit through back contact TRLA at 46.

Assuming that no interruption of the light beam 82 occurs and that light transmission characteristics in the vicinity of the door are normal, contacts PCC and PCM at and 11 are closed to energize relays P'C and PM thereby maintaining their contacts closed at line 23 so that relay TRLA remains energized until timer TRL times out and opens its back contact at 23. Upon deenergization of TRLA by the Iopening of back contact TRL the minimum start time relay TR is deenergized by opening contact TRLA at 41 and the car start relay circuit is partially enabled -by closing contact TRLA at 46. If no operation tending to maintain the doors open occurs during the TR interval, TR times out closing its back contact at line 48 to complete the car starting circuit and door closing is initiated by iirst energizing door timer DT at 28 through closed contacts CS at 29. Energization of relay CS closes contacts actuating operation of the retiring cam preparatory to starting the car and incidental thereto, energizes retiring cam relay RC (not shown) to open normally closed contact RC at line 26 whereby the relays OPS and OP are maintained deenergized during the door closing interval. Closing of front contact DT energizes the door close relay CL at 31.

It an interruption of the beam 82 occurs during the timing of TRL, contact PC at 23 is open to drop out TRLA prematurely and to energize door control relay DO at 13 through contact PC at 13. Once the doorway is `cleared and the beam 82 reestablished to again energize relay PC, door control relay DO is deenergized by the opening of back Contact PC at 13 and minimum start time relay is deenergized through the `opening of contact DO at 44 whereby upon the completion of the interval for lTR the car start relay CS is energized through the circuit AS at 44, TRLA, DO and OP at 46 and TR at 48'.

If the closing of the car doors had been initiated at the time the beam 82 was interrupted, the car doors would reopen and a TR interval following the completion of the reopening operation the car starting and door closing operations would again be initiated. In this instance the drop of PC closing contact PC at 13 and energizing relay DO- interrupts the energization of relay CL by opening back contact- DO at 31- whereby contact CL at 26 is closed to energize relay OP and cause the doors to reverse and travel in an opening direction. OP remains energized until the doors reached a full open position thereby maintaining contact OP at 43 closed to hold minimum start time relay TR energized. When the doors are fully opened and the beam 82 is reestabl-ished` to reenergize PC and deenergize relay DO, both contacts OP at 43 and DO at 44 are open in the TR circuit. TR then times out closing its contact at 48 to energize relay CS to initiate the closingof the doors and the starting of the car.

It will be seen from the above that in theI event the light beam 82 is interrupted, the door closing controls are disabled and the car cannot ordinarily be started away from the floor. In order to release this condition in the event that the ambient conditions in the vicinity of the car door are abnormal and prevent transmission of the beam 82 as where dense smoke is present, the smoke photocell relay PM is provided. This relay is deenergized when the beam -S7 is interrupted and as a result opens the door control relay DO energizing circuit at line 13 through which the car photocell relay PC normally functions tol reopen or prevent the closing of the doors. It also closes back contact PM at line 15 to energize third emergency door close relay DCE3 thereby opening its energizing circuit by opening back contact DCE3 at line 11 and maintaining that circuit open through the seal established by contact DCE3 at line 16 until the car -doors have been closed. Under these circumstances the smoke photocell relay PM also opens its contact at line 23 to deenergize standing time saver relay TRLA and closes lthe Vback contact PM at 46 to immediately issue a car startingsignal bypassing the contacts of minimum start time relay TR at 48. Accordingly as soon as the doors are fully opened and contact OP at 46 closes the car doors begin to reclose and upon completion of the 'closing operation the car starts in the normal manner. However, during the closing operation, door closure can be prevented by operating door open button 92 at 14 to energize relay DO thereby deenergizing relay CL at line 31 through open contact DO. The drop out of CL enables the door open relays to be energized by closing contact CL at 26. Contact DO opens at 46 and shortly thereafter cont-act OP at 46 opens thereby deenergizing car start relay CS. Similarly the closing door is responsive to the safe edge switch 85 on its leading edge so that if the door `encounters an obstruction, the door control relay DO at 13 is energized and functions as in response to the door open button 92.

It is desirable to avoid holding a car at any landing at which dense smoke is encountered. Such Ia condition could be encountered -at one of the main landings and under those circumstances in the absence of some supplemental circuit the start relay AS at 24 would be deenergized to open its contact at `44- and prevent the energization `of car starting relay CS. If the car at one vof the main landings has its lifting motor .conditioned for operation so that its contact LSA at 25, is closed, the dropping of relay PM due to a smoke condition closes back contact PM at 25 .to energize relay AS thereby closing the contact AS lat 44 to assure that the car starting circuit can be eiective. Thus, subject to the clearance of .the closing path of the door so that the safe edge switch 85 is not operated and the absence of an operation of the door open switch 92 so that door control relay DO is not operated the doors will reclose and the car will be started away from the main landing automatically.

Another adjunct of this invention is `disclosed in FIG. V. A suitable source of direct current supplies leads R and B of FIG. V. Directional control circuits of generally conventional nature are shown in FIG. V including a main floor relay M1 which is energized while a car is at the lower main floor through the engagement of a brush 96 with segment 97. Brush 96 is a movable element on a commutating device commonly known as a oor selector which moves generally in synchronism with car position over -a path representative of the car travel path and segment 97 is a stationary element positioned along the brush path in a position corresponding to the position of the lower main landing of the elevator whereby the circuit from 96 to 97 is completed when the car is effectively at the lower terminal. Similarly the brush 96 completes a circuit to a contact segment 98 at the position of its travel corresponding to the top landing in the system whereby when the car is effectively at the top landing a circuit is completed from brush 96 to segment 98. Car button reset relay RB is energized at each reversal of the car and is employed to reset the car buttons (not shown) at each reversal. RLU and RLD are coils of a direction throwover switch. RLU is energized to throw the car over for up travel. RLD is energized to set the car for down travel. Thus when the car comes into the bottom or lower main terminal and relay M1 is energized, coil RLU is energized at 52 through the closing of contact M1. Since the car is set for down travel and up direction control relay UL (not shown) is deenergized so that its back contact UL at 52 is closed. When the car travels to the top terminal and its brush 96 engages segment 98 direction throwover coil RLD is energized to set the car for down travel through lead 99 and closed back contact DL at 53 of the down direction control relay DL (not shown).

The down direction throwover coil can also be energized by a high call reversal operation instituted in a conventional manner to energize high call reversal relay HCR at the highest call the car is capable of answering to close contact HCR at line 53, and when the car is set for up travel, to complete the energizing circuit for RLD through closed back contact DL at 53.

An ascending car can be reversed to travel to the lower main oor upon stopping and opening its doors at a landing at which the ambient conditions are so abnormal as to prevent the proper transmission of radiant energy in the car entry. Thus incidental to the operation of smoke photocell relay PM and the resultant operation of third emergency door close relay DCE3 at 15, a DCE3 contact at 54 is closed. If the car is not at the lower main landing, so that back contact M1 is closed, and if this optional operation is rendered etective by the closing of switch 101, down direction throwover coil RLD and car button reset coil RB are energized for the ascending car through back contact DL at 53, and switch 101, contact DCE3 and contact M1 at 54. This results in the reversal of the car and in accordance with the starting control operations outlined above the starting of the car downward.

FIG. VI illustrates an alternative form of door control and car starting circuit responsive to the reduction in radiant energy transmission characteristics in the vicinity of the car entry. This circuit corresponds generally to FIG. II and can be substituted therefore to cooperate with FIGS. III, IV and, if desired, FIG. V. Accordingly, where appropriate, reference characters similar to those employed in FIG. II have been applied to corresponding elements in FIG. VI. Where contacts in FIG. VI are operated by coils in FIGS. III yand 1V, those contact locations have been indexed by slanted zone numbers to distinguish them from the contacts of the system described above. This circuit responds to the detection of smoke or other energy transmission impedingsubstances in the area adjacent the entry by arranging the door closing controls to respond to manual operation of a door close button rather than automatically as in the case of FIG. II. It is supplied by alternating current through leads P and Y connected to a suitable source. Car photocell relay PC at 61 corresponds to that at 10. Similarly smoke photocell relay PM at 62 and third emergency door close 4relay DCE3 at 73 respectively correspond to those relays at 11 and 15 of FIG. II. The

circuits controlling door control relay DO at 64 differ from those of FIG. II in that no smoke photocell relay contact PM is included in the circuit and instead a second emergency door close relay contact DCE2 is substituted therefore at line 64. Otherwise the door control relay corresponds to that of FIG. II in that at 63 a safe edge switch contact is shown and at 65 a door open button contact 92 is shown each of which will energize DO to either hold the doors open or terminate their closing operation.

Emergency expedite timer FE at 66 limits the smoke detection equipment response to an interval following completion of the door opening operation. While the door is in the process of opening, door open relay OP is energized to open its contact at `66. lf smoke detector relay PM at 62 is dropped by open contact PCM to close contact PM at 66 during the interval the door is open, the coincidence of the closure of contacts PM and OP at 66 institutes the timing of FE. Upon expiration of a suitable interval, e.g. a second, FE pulls in to enable the doors to be closed by operation of a push button in the car.

First and second emergency door close relays DCE1 and DCE2 enable door operation under conditions of detected smoke and the expiration of timer FE upon the closing of door close button 102 at 68. Before timer FE times out only relay DCE1 can be energized. Thus, the doors are assured of opening for an'intcrval sufficient for passengers at the landing to enter the car since DCE1 bars the operation of DCE2 which initiates the door closing operation.

Several modes of operation can be achieved in the circuit of FIG. VI according to the condition of

switches

103 and 105. If both switches are open, .anytime the door close button 102 is closed prior to the timing out of FE, relay DCE1 is energized from P through contacts 102 and FE at 68 to Y. DCE1 seals itself at 67 so that it remains energized as long as button 102 is closed and opens its back contact at 70 to interrupt the energizing path for DCE2. If the door close button is released and then closed after timer FE times out, DCE1 is dropped and opens contact DCE1 at 70 so that the energizing circuit vfor DCE2 is completed by the reclosng of 102 from P through 102 and contacts DCE1 and FE at 70. DCE1 will not be reenergized on the second closng of 102 since timer FE opens its back contact at With DCE2 energized and the photocell relay PC dropped as by smoke in the car entry, the door control relay remains deenergized since contact DCE2 at 64 is open. The car doors can close and the car can start lwith DO deenergized through the circuits outlined above mcluding car start relay CS energized through closed back contact DO at 46 and closed contact PM at 46 or tlmed out TR contact at 48, and door close relay CL energized through closed back contact DO at 31. Relays DCE2 and DO remain in door closing condition onl)l as long as door close button 102 is maintained closed. Release of button 102 prior to the opening of door limit switch 89 drops DCE2 to close its back contact at 64 and reenergize DO through the PC contact closed because ofthe smoke condition.

If switch 105 is closed, DCE2 seals itself in around button 102 by closing contact DCE2 at 70 so that the door close button need be closed only momentarily after FE has timed out to institute the closing operation of the doors and the doors are continuously conditioned for closing subject only to the limitations of safe edge switch 85 and door open button 92.

The circuit can also be arranged to respond to the drop of smoke photocell relay PM and door close button 102 without regard to lthe timer FE. With switch 105 open and 103 closed the drop of PM closes back contact PM at 71 to condition DCE2 for immediate response to button 102. When button 102 is closed DCE2 13 is energized and breaks the-photocell control circuit for DO so that the doors are closed and the car started. Switch 105 functions to control the seal circuit for DCEZ around 102. Thus, while switch 105 is open relay DCEZ is -ienergized only While button 1'0'2 is closed and that button `must be maintained closed until the doors close ifrPC is deenergized.`

p If'switches

103 and 105 are both closedionly a momentary closure of 102 is'necessary to establishand maintain door closing conditions through continuous energization of DCEZ. j Thirdemergency door close relay DCES` at 73 functionsjas'its counterpart in FIG. II at 15 to seal itself in at 72 -until door closing is completed and contact CL at 73 is opened when itis energized by a coincidence of a detectedy smoke condition, closing contact PM at 73, and initiationof a door closing operation, closing con- ,tact CL at 73. DCI-33 also holds relay PM deenergized until; the doors are closed through back contact DCE3 at 62 and'if the system of FIG. VI is combined with the features of FIG. V it closes a contact at 54` to institute reversal of an ascending car.

Various forms of radiant energy sources and detectors can be employed according to this invention including those generating and responsive to visible light, invisible light, electromagnetic waves, and sound waves above the audible range. A number of door control operations can be altered by the contemplated controls. LDoor closing can be retarded by simply preventing the initiation of closing or stoppinga partially closed door, by stopping and reversing a partially closed door, by slowing the .closing speed of a door, or by the imposition of timing intervals for the above functions.

From the above descriptions it is eviden-t that a number of techniques are available -whereby unusual conditions yinv the atmosphere into which a beam of radiant energy `is projected for detection of obstructions in the closing path of .a-door can be monitored. .In response to the reduction in the ytransmission of .energy in that atmos- ,phere door control and car control circuits will beset -up which supersede the usual controls afforded byradiant .energy detecting devices. These circuits permit the elevator car to continue to operate serving the building even under emergency conditions as in the case of fire so that the building can be evacuated by means of the elevators. These techniques have included the automatic reclosing and restarting of an elevator a brief interval after it is conditioned itselfv to receive a load at a landing at which the abnormal atmospheric condition is sensed, the institution' of a reversal operation to expedite evacuation of the building from a landing at which a fouled atmosphere is sensed, the Shift in control functions from a timed standing interval at a dispatching iioor under normal operation to an interval determined by operation of a door close ybutton from within the car when a fouled atmosphere is sensed, and variations on that latter mode of operation including the immediate initiation' of the door closing and car starting operation upon the operation lof a door close button under the presumed conditions and a timed delay preceding response to `such operation. In addition the option is provided for either continuous operation of a `door close button to complete the closing of the doors under the presumed conditions or4 merely the momentary operation of such controlling button. It therefore follows that the `present invention is subject -to numerous variations and modifications without departing from its spirit or scope. Accordingly, the disclosure should be interpreted as merely illustrative of the invention and is .not to be read in a limiting sense.

Having described the' invention, I claim:

1. In an elevator system including a cab having an entry, a closure for said entry, means for con-trolling the movement of said closure, a radiant energy source for projecting energy along the closing path of said closure, first means responsive to a first predetermined level of transmission of radiant energy from said first source for operating said control means to alter `closing operation of said closure, a second means for projecting radiant energy in the vicinity of said entry and means responsive to a predetermined level of transmission of radiant energy by said second'projecting means for enabling the closing movementv of said closure while said first means is respon'- sive to said first predetermined level oftransmission.

2. In an elevator system including a cab having an entry, a closure for said entry, means for controlling the movements of said closure, a radiant energy source for projecting energy alongthe closing path of said closure, means responsive to a predetermined level of transmission of radiant energy from said first source `characteristic of an obstruction in proximity to the closing path of said closure for operating said control means to retard :closing of said closure, a second projecting means for projecting radiant energy in the vicinity of said entry, and second means responsive to a predetermined level of transmission of radiant energy from said second projecting means characteristic of an atmospheric condition in the vicinity of said entry suiiicient to produce a Ifalse indication of an obstruction on said first means for enabling thev closing movement of said closure while said first means is responsive.

3. An elevator control for a cab having an entry, a closure for said entry, a first source of radiant energy projecting energy along the closing path of said closure in the region of said path ordinarily traversed by objects transferred between the interior and exterior of said cab, first means responsive to a transmission of radiant energy from said first source characteristic of -an object in proximity to the closing path of said closure for retarding a closing operation of said closure, a second means for projecting radiant energy along a path in the vicinity of said entry and outside of the region ordinarily traversed by objects transferred between the interior and exterior of said cab, and means responsive to a transmission of radiant energy by said second projecting means characteristic of an object in said path in the vicinity of said entry for enabling the closing operation of said closure while said first means is responsive.

4. In an elevator system including a cab having an entry, a closure for said entry, a first light source for projecting a beam of light along the closing path of said closure ata level normally intercepted by a transfer of load between the interior and exterior of said cab, a first light detector positioned on the opposite side of said entry and irradiated by said light beam, means for controlling the movement of said door, timing means for holding the door open a given interval after it has been opened, means initiating a door closing and car starting operation atA the end of said interval, means for retarding said door closing operation while the intensity of said light on said light detector is Ibelow a givenV value, a second means for projecting a beam of light through the atmosphere in the vicinity of said car entry, a second light detector positioned to Ibe irradiated by said 'beam from said second projecting means and means enabling a door closing operation while said retarding means is effective when the intensity of light on -said second detector is below a given value.

5. In an elevator system including a cab having an entry, a closure for said entry, a first radiant energy source for projecting `a beam of radiant energy along thel closing path of said closure at a level normally intercepted by a transfer of load between the interior and exterior of said cab, a first radiant energy detector positio'ned on the opposite side of said entry and irradiated by said radiant energy beam, means for controlling the movement of said door, timing means for holding the door open a given interval after it has been opened., means initiating a door closing and car starting operation at the end of said interval, means for retarding said door closing operation while the intensity of radiant energy on said radiant energy detector is below a given level, a

second means for projecting a beam of radiant energy through the atmosphere in the vicinity of said car entry, a second radiant energy detector positioned to be irradiated by said beam from said second projecting means and means enabling a door closing operation -while said retarding means is effective when the intensity of radiant energy on said second detector is below a given level.

6. In combination an entry, a closure for said entry, means for driving said closure between an open and a closed position, a radiant energy source for projecting energy along the closing path of said closure, first means responsive to a predetermined level of transmission of radiant energy from said first source for operating said control means to retard the closing of said closure and means for detecting a reduction in the radiant energy transmission characteristics of the atmosphere in the vicinity of said entry for enabling the closing operation of said closure while said first means is responsive to said predetermined level.

7. In combination, an entry, a closure for said entry, means for controlling movement of said closure, a light source for projecting a beam of light along the closing path of said closure in the region traversed by an object passing through said entry, means responsive to a predetermined level of transmission of said light across said closure to retard closing of said closure and a smoke detector for detecting smoke in the vicinity of said entry and in response to the detection thereof for enabling the closing movement of said closure while said first means is responsive to said predetermined level.

8. In an elevator system a car, an entry to said car, a closure for said entry, driving means for moving said closure between an opened and a closed position, a conftrol means for said driving means, a first source of radifant energy projecting energy along the closing path of fsaid closure in the region of said path ordinarily traversed by objects transferred between the interior and fexterior of said car, first means responsive to a predeterrnined level of transmission of radiant energy from said frst source for operating said control means to prevent 'closing of said closure, a second means vfor projecting radiant energy in the vicinity of said entry, second means for detecting a second predetermined level of transmission of radiant energy from said second projecting means, third means sensing the movement of said closure to a fully opened condition and means responsive to both the detection by said second means of said second predetermined level of transmission of radiant energy and the sensing by the third means of closure movement to a fully opened condition for enabling the closing movement of said closure while said first means is responsive to said predetermined level of transmission.

9. A combination in accordance with claim 8 wherein said enabling means is maintained effective until said closure reaches its fully closed position.

10. A combination in accordance with claim including means responsive to a predetermined level of transmission of radiant energy to said second radiant energy detecting means for resetting a portion of the interval measured by said timing means to expedite the closing of said closure and the starting of said elevator cab.

1l. In an elevator system including a plurality of cars :and means for dispatching cars from a given terminal, an :entry for each car, a closure for each of said entries, means for controlling the movement of each of said clozsures, a first source of radiant energy mounted on each car and arranged to project a beam of radiant energy across said entry, a first detector of radiant energy :mounted on each car and arranged to sense the level of `energy transmitted from said first source across said entry, means to prevent the starting of cars from said dispatching landing, a second means for projecting radiant energy mounted on each car and arranged to project a beam `of said `energy through a portion of the atmosphere in the vicinity of said car entry, a second detector of radiant energy for sensing the level of energy transmitted from said second projecting means and means responsive to a .detection of less than a predetermined level of energy by said second detector for releasing said car from said dispatching floor.

12. In an elevator system including a car, means for sensing the radiant energy transmission characteristics of the atmosphere in the vicinity of the car and means for setting the car for travel in a given direction in response to a given transmission characteristic as sensed by said sensing means.

13. In an elevator 4system serving a structure having a first landing constituting a primary exit from said building `and at least one additional landing, a car serving a plurality lof landings including said first landing, means for sensing the latmospheric conditions in the vicinity of the entry to said car at each landing at which said car is stopped and means responsive .to the sensing of a predetermined atmospheric condition for causing said car to travel to said first landing.

14. In an elevator system including a car serving a lower main landing `and a plurality of landings above said lower main landing, an entry for said car, means for stopping said car at each of said landings served thereby, means for detecting the yatmospheric conditions in the vicinity of said car `at each landing `at which that car is stopped and means responsive yto a predetermined atrnospheric condition as sensed by said atmosphere sensing means at a landing at which an ascending car has been stopped for reversing said ascending car to travel to said lower main landing.

15. In `an elevator system including a car having an entry, a closure for said entry, means for controlling the movement of said closure, -a first radiant energy source for projecting energy along the closing path of said closure, first means responsive to a predetermined level of transmission of radiant energy lfrom said first source for operating said control means to prevent closing of said closure, timing means for initiating the closure of said door and the starting of said car upon expiration of a predetermined interval, a second means for projecting radiant energy in the vicinity of said entry, second means responsive to .a predetermined level of transmission of radiant energy from said second projecting means for enabling the closing movement of said closure while said first means is responsive upon expiration of a second interval shorter than said given interval.

l16. In an elevator system including a cab having an entry, .a closure for said entry, means for controlling the movement of said closure, a manually actuated means within said cab for instituting the closing operation of said closure, a radiant energy source for projecting energy along the closing path of said closure, first means responsive to a predetermined level of transmission of radiant energy from said first source for operating said control means to prevent the closing of said closure, timing means for holding said closure in the open condition for a predetermined interval, a second means for projecting radiant energy in Ithe vicinity of said entry, second means responsive to a predetermined level of transmission of radiant energy from said second projecting means for enabling .the closing movement of said closure while said first means is responsive in response to the operation of said manually operable means Within said cab.

17. A combination in accordance with claim 16 including a timer measuring an interval in response to a predetermined level of transmission of radiant energy from said second projecting means to said second energy responsive means, said manually actuated closure enabling means 'being responsive only subsequent to the expiration of the interval measured by said timer.

18. In an elevator system including a car, an entry to the car, a door for said entry, means for sensing the radiant energy transmission characteristics of the atmosphere in the vicinity of the car, means for controlling 17 the operation of said door, and means for instituting the closing operation of said door by said control means in `response to the reduction of the radiant energy transmission characteristic to a given level.

19. In an elevator system including a car, a plurality of landings served by said car, an entry for said car at each landing, a door closing said entry, means for controlling yoperation of said door in a given operating pattern While la car is .at a landing, means for sensing atmospheric conditions a-t said landings in the vicinity of said entry, and means to alter lthe door operation at a landing from said given pattern and institute a closing operation of -said door in response to a predetermined atmospheric condition at said landing.

20. In an elevator system including a cab having fan en-try, a closure for said entry, means for moving said closure between an opened and a closed position, means for controlling said closure moving means, radiant energy generating and detecting means oriented for sensing obstructions in the closing path of said closure, means 18 for altering the operation of said closure in response to a sensed obstruction, means for sensing the reduction to a predetermined level of the transmission characteristic of said radiant energy through the atmosphere in the vicinity of said entry in Ia region outside that ordinairly traversed by -said obstructions and means for issuing a closing signal to said door moving means while said reduced transmission characteristic persists.

Claims

1. IN AN ELEVATOR SYSTEM INCLUDING A CAB HAVING AN ENTRY, A CLOSURE FOR SAID ENTRY, MEANS FOR CONTROLLING THE MOVEMENT OF SAID CLOSURE, A RADIANT ENERGY SOURCE FOR PROJECTING ENERGY ALONG THE CLOSING PATH OF SAID CLOSURE, FIRST MEANS RESPONSIVE TO A FIRST PREDETERMINED LEVEL OF TRANSMISSION OF RADIANT ENERGY FROM SAID FIRST SOURCE FOR OPERATING SAID CONTROL MEANS TO ALTER CLOSING OPERATION OF SAID CLOSURE, A SECOND MEANS FOR PROJECTING RADIANT ENERGY IN THE VICINITY OF SAID ENTRY AND MEANS RESPONSIVE TO A PREDETERMINED LEVEL OF TRANSMISSION OF RADIANT ENERGY BY SAID SECOND PROJECTING MEANS FOR ENABLING THE CLOSING MOVEMENT OF SAID CLOSURE WHILE SAID FIRST MEANS IS RESPONSIVE TO SAID FIRST PREDETERMINED LEVEL OF TRANSMISSION.