US2408054A - Electromechanical interlock for elevator doors - Google Patents

Description

Sept. 24, 1946. PENN 2,408,054

ELECTROMECHANICAL INTERLOCK FOR ELEVATOR DOORS Filed May 13, 1945 2 Sheets-Sheet l F 99 1 I nzrentor' [272023 lkFenn Sept. 24, 1946. w FENN ELECTROMECHANICAL INTERLOCK FOR ELEVATOR DOORS I 2 Sheets-Sheet 2 Filed May 13, 1945 Patented Sept. 24, 1946 ELECTROMECHANICAL INTERLOCK FOR ELEVATOR DOORS Emory W. Fenn, Chicago, Ill., assignor to Firecraft Corporation, a corporation of Illinois Application May 13, 1943, Serial No. 486,765

16 Claims.

This invention relates to electro-mechanical interlocks for hoistway doors for freight elevators and the like.

It is an object of my invention to provide an electro-mechanical interlock which is substantially tamper-proof.

It is a further object of my invention to provide in connection with biparting door panels an interlock which cannot be rendered inoperative unless the door suspension mechanism also is rendered inoperative.

Another object is to provide a novel, simple, compact electro-niechanical interlock mechanism.

An additional object is to provide an interlock requiring the doors at all floors to be latched before the car can be started; positively preventing opening movement of all latches while the car is in motion or is not at any floor; and positively preventing opening movement of all latches eX- cept that associated with the floor at which the car is at rest.

It is also an object of my invention to provide in an automatic or push-button controlled elevator an electromechanical interlock having the features noted above, and, in addition, whereby the car-controlling circuit is locked open when the car comes to rest at the selected floor and until a button is pushed, and may then be closed only if all doors are latched.

Further objects and advantages of the invention will appear as the description proceeds.

My invention will be better understood upon Fig. 3 is an enlarged fragmentary elevational view taken as indicated by the line 3-3 in Fig. 2

and showing details of an interlock mechanism for a push-button controlled type elevator in accordance with one form of my invention.

Fig. 4 is a fragmentary elevational View take as indicated by the line 4-4 in Fig. 3.-

Fig. 5 is a view similar to Fig. 3 but with the interlock switch automatically opened.

Fig. 6 is a fragmentary elevational view taken as indicated by the line E-6 in Fig. 5.

Fig. 7 is similar to Fig. 3 but shows the door latch in open position, the doors controlled by such latch being separated.

Figs. 8 and 9 are fragmentary plan sectional views taken as indicated by the lines 83 and =l-d, respectively, in Fig. '7.

Fig. 10 is a fragmentary elevational view similar to Fig. 7 but with the automatic switch-opening means omitted, asin the case of a non-automatic elevator.

Referring now more particularly to the drawings, I have shown an elevator well or shaft 20 (Fig. 9) defined by a wall 22 having a door opening of which the sill is shown at 2 5, a biparting door 26 comprising upper and lower door panels or sections 28 and iii, and a car 32. Attached to the wall 22 at each side is a vertical guide member 34 to which are attached upper and lower vertical guide members 36 and 31 providing guide- Ways 38 in which run guide angles 39 carried at the vertical edges of the door panels and forked guide shoes 4!! attached as at 42 near the top and bottom of each angle 39. Th forks (Fig. 9) receive and move vertically relative to the respective guide members 36 and 31, shown in other figures.

Secured to the lower door section 38 as at 48 is an arm 50 extending beyond said section and carrying adjacent its free end a bracket 52 through which the lower threaded end 54 of an anchoring member 56 extends, said end 54 receiving a nut 53 by means of which said anchoring member may be retained and adjusted in relation to the bracket member 52. Secured as at 69 to the upper part 62 of the anchoring member 56 is a chain rod 64 whose upper end is attached as at E6 to a flexible suspension member such as a cable chain 68 passing about a wheel or sheave it suitably mounted as at 12 in fixed relation to the guide members 3 5 and 36. The chain depends from the other side of the sheave and is secured as at M to the lower part of the upper door section 28. The adjustment of the doors for proper operation ofthe interlock may be modified by adjustment of the nut 58. Only the flexible portion '58 is in contact with the sheave 10 for all positions of the door sections 28 and 30.

When the door is closed, the sections 28 and 30 are disposed adjacent each other substantially as shown in Fig. 1, rubber or like bumpers 16 carried by either section being provided at suitable intervals between the bottom flange E8 of the upper section and the top flange 8B of the lower door section 30.

The doors may be latched together by any suitable mechanism, of which an illustrative form is shown in Fig. 1. Here, preferably in a suitable frame 82 secured to the inner face of the upper door section 23, there is pivotally attached as at 84 a bell crank lever 85 having a handle 88 (on the outside as well as the inside in the case of a push-button elevator) conveniently accessible to the operator on a car at rest at the associated floor level, and a second arm 98 extending in a generally vertical direction where it is resiliently maintained preferably as by a compression spring 3 92 disposed between an adjustable abutment 94 and a lug 96 formed on the lever 86. The arm 99 is formed at its lower end with a hook or catch Ilsadapted to extend through an opening I in the top 85 of the lower section 39 and adapted also, when projected through said opening I00,

to be moved bythe spring 92 under and beyond th wall of the opening I00 as shown in Fig. 1, 7

a block I06 suitably attached as to the angle 39- of the door section 28. The latch bar I04 is adapted to extend beyond the angle 39 and has an offset lug IIlB adapted to cooperate with interlock mechanism in a housing I I!) having a removable cover H2 and mounted as by suitable bolts, oneof which is shown at II4, on the stationary guide members 34 and 36.

In accordance with my invention, there is provided in association with each landing a switch lever arm IIB pivoted in the housing at I25. A locking bolt I22 may be connected to the lever I I8'inany suitable manner, and for example may have a slotted upstanding boss I24 pivotally connected as at I26 to a yoke or fork I28 on the lever I I8. ifihe housing I II} preferably has a guide opening I30 for sliding movement of a projection I32 extending from the bolt I22. The bolt I22 at the end I34 thereof opposite the projection I32 is adapted to slidingly bear on the bearing surface I36 of the housing III], the only other sliding contact between the bolt and the housing occurring between the bottom of the opening I32 and the bottom of the bolt extension I32, whereby friction is at a minimum. Said end I34 of the bolt I22 has a notch I33 open and flared at the top as at I411 to facilitate entry of the lug I08 on the latch bar I04 into the notch.

The lever H8 is provided with an insulating plate or block I42 from which projects a pin I44 about which a coil spring I46 is disposed, said pin having a non-circular portion passingthrough a metallic bridge member I48 and formed at its free end to retain the bridge in association therewith, the spring I46 constantly urging the bridge I48 toward the free end of the pin. The'bridge Iflrnay be'provided with electric contact points I59 and I52, adapted to engage respectively stationary contacts I54 and I55 mounted on an insulating block I58 fixed to the housing I III. The contacts I 3 and I56 are in an electric circuit from which wiring I68, suitably insulated, extends through the housing I ID to a relay I62 controlling the elevator car control motor I54 connected to the electric line. The bridge I48 with its contacts I55 and I52 and the points I54 and I56 constitute a switch I66 which, with the switch I68 in series with the source of supply I6? and controlled directly by the operator, as by pushbutton, in an automatic elevator, or otherwise in a non-automatic elevator, controls the operation of the motor relay and hence themotor.

Mounted in suitable bearings in the housing III is a rock shaft I'II] having an outward extension to which is adjustably secured an arm I'I2 carrying a cam roller I I4 adapted to cooperate with a stationary cam I on the car if the car is not push-button controlled or with a retiring cam (not shown) with which the car, if pushbutton controlled, is equipped. Referring now more particularly to the latter type of car, it is well known that pushing any button closes a switch I68 and this operates a solenoid to retire the retiring cam, and if the car is put into motion the cam will remain in a retired position. When the car nears the selected floor, the retiring cam will be automatically projected toa position at which it operates to engage the roller I14 and swing the arm I72 to a more nearly vertical po- 'sition, thereby opening the switch IE6 at the proper time to insure the cars coming to rest The use with its floor at the level of the sill 24. to which I put the retiring cam will appear presntly.

Fixed for rotation with the rock shaft I'iIl within the housing IIII is a locking arm I18 urged by a spring I in a direction to position the end I82 of the locking arm behind a locking lug I84 on the switch arm I'IB (Fig. 4), so as to obstruct movement of the switch arm toward the left as shown in the drawings, 1.- e., toward openswitch position and prevent unlatching of -the door, the locking arm I18 however being movable by the-acticnof the retiring or other cam on the roller I14 against the resistance of said spring, to a position (Fig. 6) permitting open-switch movement of the switch arm H8. I

Also mounted for rotation with the rock shaft I'IIJ is-a safety arm I85 which may be employed in connection with a push-button controlled car, said arm I86 carrying a cam I88 of insulation material movable, by the action of the retiring cam, between the contact bridge I48 and the adjacent stationary contact I54 to locksaid bridge in'open-switch position, said safety arm being urged by the spring I89 toward inoperative position (Fig. 3), which it occupies upon retirement of the retiring cam. v

The housing I III has an opening I90 permitting the bolt I22 to be projected partially out of the housing, the housing being provided with a suitable stop I92 e'ngageable with the lever "I I8, or other suitable means being provided, to limit the extent to which the bolt I22 may be projected fromthe housing toward the door.

When the door is open, i. e., when the door panels 23 and-3i! are substantially apart, the latch bar I94 is entirely outside of the housing III] as may be gathered from Fig. '7, an adjustable stop I94 (Fig. 1) being provided to limit the extent towhich the latch bar I04 may be projected by the V latch spring 92, I a

When the doorsections are latched togethe and the car has started on its trip, the parts are disposed as shown in Figs. 1 to 4, wherein, referring particularly to Fig. 3, it will be noted that the switch I66 is closed, the safety switch-opening cam I38 is in inoperative position, and the end I 82 of the locking arm I18 is disposed in obstructing relation to the lug I84 on the lever H8, as shown in Fig. 4, making it impossible for the latch bar IE4 to be retracted. Thus it is impossible to accidentally open the switch I65 when the car is in motion and until the retiring cam on the car operates on the roller I'I4. When the retiring cam thereby separating the'contact I55 from the contact I54 so as to open the switch I66, bringing the car 32 to a stop with its floor flush with the sill 24. This rotation of the locking arm I13 causes the end I82 of said arm to be shifted to a position out of obstructing relation to the lug I a l of the lever arm H3, as shown in Fig. 6.

Now the operator raises the'handle 88 (Fig. l), pulling the latch bar N34 to the left from its Fig. position, the lug I84 moving past the locking arm nd I52 to the extent permitted by the housing Illi, as at I92, until the interlock mechanism is arranged substantially as shown in Fig. 7 (in which however the latch bar I04 is shown some what elevated, for a purpose which will appear). In this arrangement the contact I52 has separated from the contact I56. Raising the handle 88 also moves the hook 98 laterally sufiiciently to enable it to passout of the opening his of the lower door panel 35 as the door panels 28 and 3d are separated. As the door panels are separated, the latch bar we passes upwardly out of the notch or socket I38 and clear of the housing 5 Iii. It will be noted that when the locking bolt I22 is withdrawn by the latch bar I04 as just described, the projection I32 on said bolt is shifted to a position enabling the upper end 62 of the anchoring member 56 to pass down clear of such projection, as is evident from Fig. 7, so that the further upward and downward movements of the respective door panels 28 and 30 are unobstructed. The chain rod 64 is guided by a guide element 696 suitably attached as at I98 to the housing I Iii.

The adjustable stop I 94 (Fig. 1) may be threaded in a bracket 2% mounted on the door panel 28 and serving as a guide for upward and downward movement of a gravityor spring-actuated detent or keeper 202 having a laterally projecting lug 2M adapted to be accommodated in a notch 29% in the latch bar I04. The keeper has its lower end 268 extending through a guide opening 2H1 in the bottom I8 of the upper door panel 28 and adapted to rest on the top 89 of the lower door panel 38 when the door is fully closed as shown in Fig. 1 and until the doors are separated a slight amount, say about /8 inch. When the operator raises the handle 38, not only is the hook 93 shifted laterally to an extent permitting it to pass through the opening I50 when the door panels are separated, but the latch bar I M is moved to the left (Fig. 1) until said bar is free of the housing IIU. At this time, the notch 206 in the latch bar I64 is in a position to receive the" lug 204 of the keeper 2% upon slight separation of the door panels. When the operator raises the handle 88 he not only moves the hook 98, latch bar HM and locking bolt I22 to open the switch I85, but, as a part ofthe same operation, he raises the upper door panel 28 and thus, through the chain 58 and chain rod 64, enables the lower panel 30 to gravitate downward, whereupon the notch 29% in the latch bar I04 receives the lug 204 on the keeper 292, and thus the latch bar I04 is retained in its retracted position until the door panels are again in such proximity that the top 30' of the lower panel 39 engages the bottom 2138 of the keeper 202 and lifts the lug 2M sufiiciently to separate the lu from the notch 206.

As the doorsproceed to separate, the latch bar lug I08 passes above the top of the housing opening Hill, at which position the housing obstructs such movement of the latch bar IM as would tend to return the locking bolt I22 to switch-' closing position. When the separation of the door sections has proceeded to such an extent that the latch bar lug I03 is completely free of the locking bolt I26, and until the separation of the door sections is complete, the projection I32 of the locking bolt I22 is injuxtaposition to the served that the means just described for posi- LIO tively preventin closure of the switch independently of the wedge cam IE8 when the doors are not latched involves a substantial improvement over the prior art, since it is dependent upon the parts 5% and 54, the removal of either or both of which would render inoperative the suspension means whereby the doors are operated together. Thus my construction for preventing. closing of the switch IE6 while the door is open is tamperproof.

When the door panels 28 and 3d are fully open, stop members 2 I2, of which one is shown in Fig. 9, fastened to the top of the lower door section 38, engage the sill 24 with a trucking plate 2| 4 at the top of said lower section substantially flush with said sill.

When it is desired to proceed with the car, the operator closes the door. As the upper door section 28 descends, the latch lug I63 rides free as indicated in dotted lines in Fig. '7, where it is held by the detent 264, in position to descend into the notch I33 in the locking bolt I22, entering said notch as the door panels come together. Thus the latch bar lil l has no frictional contact with the housing I Hi or other part during the opening and closing of the door. Shortly before the door is closed, the bottom 2% of the keeper 2%?2' engages the top 89 of the lower panel 36 and, as the panels thereafter approach closed positions, the keeper is raised, so that the keeper lug 20 i is freed of the notch 2% in the latch bar IML. This occurs substantially when the upper end of the latch lug I68 has passed below the top of the opening I538 in the housing Hill, the lug I238 being then disposed substantially entirely in the looking bolt notch 53%, the hook 9% has passed below the lower panel flange 85], and the projection I532 on the locking bolt I22 has passed below the upper part 62 of the anchoring member 55. The compression spring 92 then automatically moves the latch bar EM, the hook 558 and the locking bolt I22 to the right as shown in the drawings. bringing the parts into the relation shown in Fig. 5. At such time the locking lug Hi l of the switch lever I I8 is spaced from the adjacent wall 2I6 of the housing sufliciently to permit the end I82 of the locking arm Ill! to pass therebetw'een, and it will be noted further that while the contacts I52 and IE5 are allowed to engage, the Wedge cam I83 on the arm IE5 has prevented the contact I56 from engaging the contact I54 with the result that the switch I65 is still open. The operator now pushes a car control button (not shown). Pushing of the button closes the switch 58 (Fig. '7) and retires the retiring cam from the roller I14, enabling the spring I to rotate the locking arm 57% until the end I82 of said arm is disposed between the lug IM of the switch lever I 18 and the adjacent housing wall M5, said spring thereby also rotating the rock. shaft lit! and with it the wedge cam arm 586, drawing the wedge cam I88 out of the way of the contact bridge Hi8, which is thereupon moved by the spring I46 in a manner to enable the contact I50 to engage the contact I54 and thereby close the I switch I65 so as to operate the relay I62 and hence the car motor I64 to move the car,

The safety wedge cam I88 is provided to satisfy Underwriters Laboratories requirements for States requiringsuch a safety feature. However, this feature may be omitted as shown in Fig. 10, wherein (except for the cam I88) the construction and operation are identical with those hereinabove set forth.

In the event the arrangement of Fig. 10 is employed, the cam roller I14 is moved by a stationary cam I'IS (Fig. 2) on the car every time the elevator car approaches a floor, thereby moving the locking arm I18 to the position shown in Fig. 6. Thus the switch I66 cannot be opened unless the car is substantially at a floor. The switch IE6 is in series with a switch controlled by the operator, such as the switch I68 shown in Fig. 7, enabling him to bring the car to a stop at any floor without preselecting the floor. If, after the locking arm I18 has been so shifted by the stationary cam on the car, the operator does not wish to stop the car at the adjacent floor, the stationary cam moves past the roller I'M, allowing the spring I80 to return the locking arm I18 to its obstructing position as shown in Fig. 4, thereby positively preventing accidental opening of the switch I66. If, at the time the locking arm I78 is shifted to the position shown in Fig. 6, the car is brought to a stop, then the operator can raise the handle 83 to thereby retract the latch bar I534 sufficiently to withdraw the locking bolt I22 and thereby open the switch I66. Thereafter the switch I55 can be closed only provided the projection I32 on the locking bolt I22 is below the part 62 of the anchoring member 56, and the latch bar lug I918 is below the top of the opening I99 in the housing I II at which time the door is closed. When the car is thereupon started, the stationary cam thereon moves beyond the roller H4, allowing the spring I89 again to move the locking arm III! to its Fig. 4 position preventing opening of the switch I66.

It will be apparent from the foregoing that I have provided a fool-proof, simple and compact interlock which is entirely dependable and has allof the advantages herein set forth.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the invention, and that the same is not limited to the particular forms herein disclosed, except insofar as indicated by the appended claims.

I claim:

1 In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said car, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, means connecting said sections for simultaneous movement, latch means including a movable latch member for each door, a motor control switch associated with each door and including a switch arm movable into closed position by said latch member when said latch member ismoved to latching position, and a motor control circuit including said switches, said motor being operative only when both switches are closed, and means for preventing closure of the second switch when said door, is open, said closurepreventing means being provided on said connecting means so as to be irremovabl e without rendering said connecting means inoperative.

2. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said 2 car, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, means connecting said sections for simultaneous movement, latch means including a movable latch member for each door, a motor control switch associated with each door and including a switch arm movable into closed position by said latch member when said latch member is moved to latching position, a motor control circuit including said switches, said motor being operative only when both switches are closed, means for preventing closure of the second switch when said door is open, aid closure-preventing means being provided on said connecting means so as to be irremovable without rendering said connecting means inoperative, and means for preventing opening of said second switch when said car is not at a floor.

3. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said c r, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, means connecting said sections for simultaneous movement, latch meansincluding a movable latch member for each door, a motor control switch associated with each door and including a switch arm movable into closed position by said latch member when said latch member is moved to latching position, a motor control circuit including said switches, said motor being operative only'when both switches are closed, means for preventing closure of the second switch when said door is open, said closure-preventing means being provided on said'connecting means I so as to be irremovable without rendering said connecting means inoperative, means for preventing opening of said second switch when said car is not at a floor, and means including a cam on said car for rendering the second preventing means inoperative when said car is at rest at a floor. r

4. In an elevator, a hoistway, a car in said hoistway, an electric motor for said car, pushbutton control means for said motor, a door at each floor of said hoistway, a motor control switch comprising a movable contact arm, a motor control circuit including said push-button control means and switch, said motor being operative only when a push-button switch and the other switch are both closed, a latch member for said door and operative uponsaid switch arm to open and close said other switch, means movable with'said door and operative to prevent said arm from closing said other switch when said door is open, and means controlled by said car and preventing accidental closure of said other switch when'said car is substantially at rest at the selected floor.

5. In an elevator, a hoistway, a car in said hoistway, an electric motor for said car, pushsaid door and operative upon said switch arm to.

open and close said other switch, means movable with said door and operative to prevent said arm from closing said other switch when said door is open, means controlled by said car and preventing accidental closure of said other switch when said car is substantially at rest at the selected floor, and means controlled by said car for pre venting switch-opening movement of said switch arm when said car is not substantially at the selected floor.

6. In an elevator, a hoistway, a car in said hoistway, an electric motor for said car, pushbutton control means for said motor, a door at each floor of said hoistway, a motor control switch comprising a movable contact arm, a motor control circuit including said push-button control means and switch, said motor being operative only when a push-button switch and the other switch are both closed, a latch member for said door and operative upon said switch arm to open and close said other switch, means movable with said door and operative to prevent said arm from closing said other switch when said door is open, means controlled by said car and preventing accidental closure of said other switch when said car is substantially at rest at the selected floor, and means controlled by said car for preventing switch-opening movement of said switch arm when said car is not substantially at the selected floor, the last mentioned means being inoperative when said car is substantially at the selected floor.

'7. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said car, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, one of said sections having a latch member, a relatively stationary switch mounted in said hoistway in association with each floor and including a movable contact member, a motor control circuit including said switches, said motor being operative only when said switches are closed, and means connecting said door sections for simultaneous movement, a connecting element substantially rigid with one of said sections and forming an essential part of said connecting means, whereby removal of said element would render said connecting means inoperative, said element having a recess disposed to receive a part carried by said arm only when said door is closed, to permit said arm to move into switch-closing position, a portion of said element adjacent said recess being disposed to obstruct movement of said arm into switch-closing position for all open positions of said sections.

8. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said car, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, one of said sections having a latch member, a relatively stationary switch mounted in said hoistway in association with each floor and including a movable contact member. a motor control circuit including said switches, said motor being operative only when said switches are closed, means connecting door sections for simultaneous movement, a connecting element substantially rigid with one of said sections and forming an essential part of said connecting means, whereby removal of said element would render said connecting means inoperative, said element having a recess disposed to receive a part carried by said arm only when said door is closed, to permit said arm to move into switchclosing position, a portion of said element adjacent said recess being disposed to obstruct movement of said arm into switch-closing position for all open positions of said sections, and means yieldably urging said contact am into switch-closing position when said door is closed.

9. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said car, a motor control switch under the control of the car operator, a biparting do'or comprising door sections associated with each floor of said hoistway, one of said sections having a latch member, a relatively stationary switch mounted in said hoistway in association with each floor and including a movable contact member, a motor control circuit including said switches, said motor being operative only when said switches are closed, means connecting said door sections for simultaneous movement, a connecting element substantially rigid with one of said sections and forming an essential part of said connecting means, whereby removal of said element would render said connecting means inoperative, said element having a recess disposed to receive a part carried by said arm only when said door is closed,

to permit said arm to move into switch-closing position, a portion of said element adjacent said recess being disposed to obstruct movement of said arm into switch-closing position for all open positions of said sections, and means including a latch member for moving said contact arm into and out of switch-closing position when said door is closed while said car is substantially at rest at the floor associated with said door.

10. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said car, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, one of said sections having a latch member, a relatively stationary switchmounted in said hoistway in association with each floor and including a movable contact member, a motor control circuit including said switches, said motor being operative only when said switch-es are closed, means connectin said door sections for simultaneous movement, a connecting element substantially rigid with one of said sections and forming an essential part of said connecting means, whereby removal of said element would render said connecting means inoperative, said element having a recess disposed to receive a part carried by said arm only when said door is closed, to permit said arm to move into switch-closing position, a portion of said element adjacent said recess being disposed to obstruct movement of said arm into switch-closing position for all open positions of said sections, means including a latch member for moving said contact arm into and out of switch-closing position when said door is closed while said car is substantially at rest at the floor associated with said door, and means preventing unlatching movement of said latch member when said car is not substantially at rest.

11. In an elevator or the like, a hoistway, a car in said hoistway, an electric motor for said car, a motor control switch under the control of the car operator, a biparting door comprising door sections associated with each floor of said hoistway, one of said sections having a latch member, a relatively stationary switch mounted in said hoistway in association with each floor and including a movable contact member, a motor control circuit includin said switches, said motor being operative only when said switches are closed, means connecting said door sections for simultaneous movement, a connecting element substantially rigid with one of said sections and forming an essential part of said connecting means, whereby removal of said element would render said connecting means inoperative, said element having a recess disposed to receive a part carried by said arm only when said door is closed, to permit said arm. to move into switch-closing position, a portion of said element adjacent said recess being disposed to obstruct movement of said arm into switch-closing position for all open positions of said sections, and means preventing switch-opening movement of said contact arm when said car is not substantially at rest.

12. In an elevator, a hoistway, a car in said hoistway, an electric motor for said car, pushbutton control means for said motor, a door at each floor ofsaid hoistway, a motor control switch comprising a movable contact arm and a biased switch contact, a motor control circuit including said push-button control means and switch, said motor being operative only when a push-button switch and the other switch are both closed, a latch member for said door and operative upon said switch arm to open andclose said other switch, means obstructing open-switch movement of said contact arm while said car is en route to but substantially remote from the selected floor, and means controlled by said car and simultaneously opening said other switch and moving said obstructing means to non-obstructing position when said car substantially reaches the selected floor, said controlled means including a member forced by said car to move said contacttd open-switch position in opposition to the bias thereon.

13. Inan elevator, a hoistway, a car in said hoistway, an electric motor for said car, pushbutton control means for said motor, a door at each floor of said hoistway,a motor control switch comprising a movable contact arm and a biased switch contact. a motor control circuit including said push-button means and switch, said motor being operative only when a push-buttonswitch and'the other switch are both closed, a latch member for said door and operative upon said switch arm to open and close said other switch, means obstructing open-switch movement of said contact arm while said car is en route to but substantially remote from the selected floor, means controlled by said car and simultaneously opening said other switch and moving said obstructing means to non obstructing position when said car substantially reaches theselected floor, said controlled means including a member forced by said car to move said contact to open-switch position in opposition to the bias thereon, and means movable with said door to prevent said arm from closin said switch when said door is open.

14. In I an elevator installation including a hoistway having a plurality of landings with each of which the panels of a vertically sliding biparting hoistway door and switch are associated, a car having a retiringcam and disposed in said hoistway, a motor for said car, a push-button control for said motor, a motor control circuit including said switch. and push-button control,

,. said motor being operative only when said switch 12 for said door and connected with said switch arm when said door is closed and being movable to latching position when said car is at rest at the associated landing, a member movably mounted at each landing and yieldably held in a position locking said switch arm in closed-switch position when said door is latched, said member being movable from such position by the retiring cam to unlock said switch arm and against the resistance of said spring to lock said bridge in openswitch position until said cam is retired while said switch arm is in closed-switch position, said latch bar being retractable, when said switch arm is unlocked, to unlatch said door and move said switch arm to open-switch position, means for maintaining said latch bar inretracted position while said door is open, means connecting said door sections for simultaneous movement, and means including said connecting means for looking said switch arm in open-switch position while said door is open.

15. In an elevator installation including, a hoistway having a plurality of landings with each of which the panels of a vertically sliding biparting hoistway door and a switch are associated, a car having a retiring cam and disposed in said hoistway, a motor for said car, a push-button control for said motor, a motor control circuit including said switch and push-button control, said motor being operative only when said switch and a push-button switch are closed, the first switch having a movable arm and a springpressed contact, a latch bar for said door and connected with said switch arm when said door is closed and being movable to latching position when said car is at rest at the associated landing, a member movably mounted at each landing and yieldably held in a position locking said switch arm in closed-switch position when said door is latched, said member being movable from such position by the retiring cam to unlock said switch arm and against the resistance of said spring to lock said contact in open-switch position until said cam is retired while said switch arm is in closed-switch position, said latch bar being retractable, when said switch arm is unlocked, to unlatch said door and move said switch arm to open-switch position, means for maintaining said latch bar in retracted position while said door is open, means connecting said door'sections for simultaneous movement, and means including said connecting means for locking said switch arm in open-switch position while said door is open.

16. In an elevator, a' hoistway, a car in said hoistway, an electric motor for said car, pushbutton control means for said motor, a door at each floor of said hoistway, a' motor control switch comprising a movable contact arm, a-

motor control circuit including said push-button control means and switch, said motor being operative only when a push-button switch and the other switch are both closed, a latch member for said door and operative upon said switch arm to open and close said other switch, means movable with said door and operative to prevent said arm from closing said other switch when said door is open, means controlled by said car and preventing accidental closure of said other switch when said car is substantially at rest at the selected floor, and means for moving the last mentioned means to inoperative position before said car starts.

EMORY W.. FENN.

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