US2512315A - Emergency electrical control device - Google Patents

Description

June 20, 1950 w. F. EAMES 2,512,315

EMERGENCY ELECTRICAL CONTROL DEVICE Fliled Nov. 28, 1947 7- Circuit 3 u; 103 f :IF "w 111 if' ya 99 77 107 I 39 75 f/ )l g l 'L/ i 63a l 109i Q) .97

4 a ,10a 95 l F f/ j -79 as 'wlTNEssEs: lNvENToR ATTORNEY Patented June 20, 1950 EMERGENCY ELEC TRICAL CONTROL I DEV CE William F. Eames, Westfield, N. J., assigner to Westinghouse Electric Corporation, East Pitts'- burgh, Pa., a corporationI of Pennsylvania Application November 28, 1947,. Serial N o. 788,548

11 Claims. l

This invention relates to emergency electrical control devices and it has particular relation to elevator systems having emergency release mechanism permitting operation of an elevator independently of safety interlocks associated with the elevator.

ln electricall apparatus it is conventional practice in many cases tov provide safety locks which prevent incorrect or hazardous operation of the apparatus. For example in an elevator system, it is conventional practice to provide each elevator door or hatchway door with a door switch. The door switch has contacts which are open when the associated door is open and which are closed when the associated door is closed. The door switches are connected in series for the purpose of preventing operation of the associated elevator when one or more of the doors are open. However, under certain emergency conditions, it is desirable to permit operation of the elevator despite the fact that one or more of the doors may be open. For this reason, it is the practice to provide the elevator with a manuallye operable emergency release switch for permit'- ting operation of thev elevator when one or more of the doors is open.

A conventional emergency release switch may be mounted on an elevator car behind a frangible panel. In order to actuate the switch, it is iirst necessary to remove or break the frangible panel. Following such removal of the panel, the switch may be actuated to bypass the safety interlocks.

The removal of the frangible panel does not interfere with the normal operation of the conventional elevator system. If thedoors are all closed, the associated elevator may loe operated in the normal manner. For this reason, when the frangible panel has once been removed or destroyed, the elevator operator may continue to operate the elevator in the normal manner without requesting replacement of the frangible panel". Such operator' is undesirable;

To illustrate the problem further, let it beV as-A sumed that a locking devi-ce for an elevator liatchway door fails mechanically and the door bounces open as the elevator' car leaves the associated floor. The opening of the door switch stops the elevator car. However, by operating the emergency release switch, the elevator operator can return to the door for the purpose of closing the door. Since he may then continue to operate the elevator car in a normal'` manner', the elevator operator may neglect tov report the defective door tok his building maintenance department. Consequently, the defective`l door re'-v mainsa source of danger to inquisitive or thoughtless persons.

In accordance with the invention an elevator system is provided wherein an emergency release switch is associated' with a frangible panel. However, removal or destruction of the frangible panelJ prevents normal operation of the elevator system- The elevator can be operated only if the eleva-tor operator continuously actuates the emergency release switch. Since such continuous actuation of the switch is' tiresome, the elevator operator soon requests replacement of the frangible panel, and is required by his supervisor to explain the reason for the removal of the panel.

It is therefore an object of the invention to provide an improved emergency release device for electrical systems.

It is a further object of the invention to provide a-n elevator system with an emergency release switch wherein a frangible panel must be removed or destroyedV to actuate the emergency release switch and wherein removal ofthe frangible panel prevents normal operation of the elevator' system.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawing, in whichz' Figure 1 is a schematic view of an elevator system embodying the invention;

Figs. 2 and 3 are schematic views of portions of the system of Fig. l with parts shown in different conditions of operation, and

Fig. 4 is a view inY sectional elevation of an electrical switch device suitable for the system of Fig. 1.

Referring to the drawing, Fig. l shows an elevator car I and a counterweight 3 therefor which are connected by one or more flexible cables 5 which pass over a sheave 1. The sheave 'l is securedv to a shaft 9 which also carries the armature of a direct-current motor Il and a brake drum I3 having suitable brake shoe mechanism I'5A associated therewith.

Forv rotating the shaft 9 the armature ofV thel direct current motor il is electrically connected across the terminals of the armature of a direct current generator H. This generator armature is secured to a shaft I9 which also carries the rotor of an induction motor 2l and the armature of a direct current generator 23. rEhe direct current genera-tor 23 supplies direct current for energizing the control circuits of the elevator system and for energizing the fields oi the gen 3 erator I1 and the motor II. Energy for the polyphase motor 2I may be derived from a suitable source of polyphase energy represented by phase conductors LI, L2 and L3.

Operation of the elevator system is initiated in a conventional manner by a car switch 25 which is mounted in the elevator car I. (The position of the switch inthe car is illustrated in dotted lines. For the purpose of depicting connections clearly, the switch is shown removed from the car.) The car switch initiates energization of suitable elevator control circuits 21 for controlling the energization of i'lelds associated with the generator I1 and the motor II and the enerization of solenoid mechanism for controlling the brake shoe mechanism I5. Sinceany conventional driving system may be employed for the elevator car I, it is believed that a further description of the system is unnecessary.

As previously pointed out, elevator systems have various interlocks for preventing undesirableor hazardous operation of the elevator system. For example, in Fig. 1 an interlock relay 29 is provided which has a solenoid connected in series with door interlock switches Y for energization from a suitable source of direct current represented by conductors L4 and L5. Ordinarily, one door interlock switch would be provided for the elevator car and each hatchway door and the number of doors consequently would depend on the specific elevator installation.

, For the purpose of discussion, it will be assumed that the elevator car I has four hatchway or corridor doors DI, D2, D3 and D4 which are located at the four floors served by the elevator car. Each of the elevator doors carries a contact 3i which engages, a stationary contact 33 when the associated door is closed. When the door is opened, in the direction of the arrow, the contacts separate to open the associated circuit. 4 Such door interlock switches are well known in the art. By inspection of Fig.k l, it will be observed that if any-oi the doors isopen, the relay 2e cannot be energized to close its contacts.

Ordinarily, the relay 29 would be providedvvith contacts in the various car running circuits for the purpose of preventing operation of the elevator system when any of the doors is open. For the purpose of illustration, it is believed sufcientto indicate one set of contacts 35 which are connected in series with the car switch 25. Since the' contacts 35 are, open when the relay 29 is deenergized, it follows that closure of the car switch 25 cannot initiate operation of the associated elevator system unless all of the doors DI, D2, D3 and D4 are closed.

It will be recalled that in emergencies operation of the elevator system may be desired despite the fact that one or more of the doors may be open, To permit such emergency operation, an emergency release device 31 is provided which includes a pair of contacts 39 and 4I which are connected by a bridging contact t3. The contacts 39, 4I and t3 cooperate with conductors 45 and I1 to bypass the door switches associated with the doors DI, D2, D3 and D4. (The device 31 is located in the car I as shown in dotted lines. To facilitate illustration of the circuit connections, the device 31 is shown removed from the car l.)

51. The panel 51 may be constructed of any frangible material which may be destroyed without damaging associated parts ofthe apparatus. For example, porcelain or glass are suitable materials, and glass ordinarily would be employed for the rangible panel. A hammer (not shown) maybe locatednear the frangible panel to facilitate breakage of the panel by an operator.

If the emergency release switch device 31 com- .prised only the parts thus far speciiically described, destruction or removal of the frangible I panel 51 would not interfere with the normal 0p- The bridging contact lis is provided with an operating button 49 and has a rod 5I projecting therefrom to terminate in a head 53. A spring 55 engages the head 53 to urge the button 49 into engagement with a frangible member or panel eration of the elevator system. Consequently, an elevator operator may continue to operate his elevator without replacing the irangible panel.

In order to make it impossible to operate the elevator system normally following removal of the frangible panel 51, the emergency release device 31 is provided with an additional switch for interrupting the interlocking circuit containing the door switches. The additional switch includes two contacts 59 and 6I which are connected in series with the doorfswitches. yA bridging contact t3 normally establishes a connection between the contacts 59 and SI to complete an energizing circuit for the relay 29l when the door switches are closed. The bridging contact 63 may be biased against the contacts 59, SI or the head 53 by means of a spring 65. It will be understood that an energizing circuit for the relay 29 may be completed through either of two parallel arms. One oi these arms comprises the conductor 45, the contacts 39, 4I and 43 and the conductor A1. The remaining arm comprises the contacts 59, Si and 53 and the door switches.

The system of Fig. 1 represents the normal condition of the emergency release device. In this condition, the door switches are effective for controlling the energization of the relay 29.

When emergency operation is desired, the panel 51is removed or broken, as illustrated in Fig. 2. Following breakage of the panel 51, the spring 55 forces the button 49 through the position normally occupied by the panel 51. The resulting movement of the bridging contact 63 by the head 53 opens the contacts 59 and 6I. to prevent subsequent energization of the relay 29, through the door switches..

Let it be assumedthat the condition necessitating operation of the emergency release switch results from the presence of an open door D4. In order to move the car under such conditions the elevator operator manually presses the button 4S against the bias ofthe spring 55 to close the contacts 39 and 4I (Fig). Duringy such movement of the button, the'spring 65 permits suitable adjustment of the bridging contact 63. Since the contacts 39, 4I and 43 now bypass the open door switch of the door D4, the relay 29 is energized and the elevator car can be moved as desired.

By reference to Figj2, it vwill be observed that breakage of the panel 51 is accompanied by movement of both of the bridging contacts 43 and 63 away from their associated contacts. Consequently, the -elevator operator cannot operate the car thereafter' in the normal manner. If he desires to move the elevator car, he must always press the button 49 to close atleast one of the associated pairs of contacts. Since this is a tiresome act, the .elevator operator soon requests replacement of the panel 51.

Although the operating mechanism for the emergency release d-e'vice'31 illustrated in Figs. 1,

2 and .3 may 'be' employed, ysomcwh atdifferent op,

erating mechanism is illustrated in Fig. 4; In Fig. 4; twocontactsz5'9a and'6|a are shownwhich correspond to the contacts 59 and 6| of Fig. 1. The contacts 59a and Bla are secured by machine screws 1| to a support 13' which may be constructed ofV a suitable insulating material,y suchas phenolic resin. The conta-cts 59a and Bla have associated therewith, a bridging contact 63a which corresponds to the bridging contact 63 of Fig. l. The bridging contactliSa includes a strip 15 ofv electroconductive springmaterlal having'at one end a contact 11 for engagement withthe contact 59a and secured atits oppositeend to an electroconductivearm 19. This' arm vhas 'atongue 8| which extends through an opening inthecontact B'Ia toV permit a pivoting'movement of the arm about the opening. A` pin 83'is secured to the contact Sla andextendsthrough the arm119. This pin has a washer' secured to one end'for thepurpose ofr compressing between the arm 19 and-thel washer a spring 81. By inspection of Fig. 4, it will be observed that the spring 81l biases the arm 19 in a direction to urge the con.- tact 11 away from the associated contact. 59a. The upper end of the arm 19 is bent to form a protuberance` 89 which operates as a cam follower.

For actuatingl the bridging contact 63a, a cam 9|is secured to a shaft 93 which is mounted for rotation relativ-e to the support 13. A' crank arm 95A is secured to the shaft 93 for rotating the shaft and the cam as a unit.

A second bridging contact 43a is providedwhich corresponds to the bridging contact 43 of Fig.v l. The bridging contact 43a is similar in construction to the bridging Contact 63a but is spaced therefromV in a direction parallel to the shaft 93. The bridging contact 43a has associated therewith contacts which are similar to the. contacts 59a and Sla and cooperates with its associated contacts in the same way thatthe .bridging member 63a cooperates with its fixed contacts 59a and Gla. For actuating the bridging contact 43a against thebias of its spring,a cam 91v is secured to the shaft for the purpose of engagingfthe protuberance or cam. follower 99A of the bridging contactv 43a. 'Ihe support 13. may bek secured to a base member ||l| inany suitable manner, asby means of machine screws. |03.

Rotation of the crank arm 95-is eifectedby a plunger |05 which is slidably disposed. in an opening |61 -formed in the-support 13. The crank arm 95 carries a pin |01. which enters a slot |09 located in one end of the` plunger. |05. At its opposite end, theplunger |05 has secured thereto, a hollow button 49a which corresponds to the button 49 of Fig. 1; This button contains a spring which urges the button 49a and its associated plunger to the left relative to the sup.- port 13, as viewed in Fig. 4.

The cams 9| and 91 are shaped'to produce successive operation of the bridging contacts 63a and 43a. With the button in the positionillustrated in full lines in Fig. 4, the cam 9|` maintains :the bridging contact 63a in bridging relationship relative to its associated fixed: contacts. The bridging contact 43a, however, does not bridge its associated iixed contacts. These positions of the bridging contacts correspond to the positions of the bridging contacts 63 and 43 in Fig. 1.

If the spring Il is permitted to move the button 49a from the intermediate position represented in full lines in Fig. 4 to a position Wherein the end of the button is represented by the broken line H3, the resulting movement of the plunger |05 acting throughthe crank arm 95 rotates the shaft 93 in a clockwise direction, as viewed in Fig. 4, to release the bridging Vcontact 63a. As the cam 9| is moved in a clockwise direction by rotation of the shaft 93 theV cam releases thecam follower B9 and permits the spring 91 to urge the bridging contact 63a away from the fixed contact 59a. The resulting positions of the various parts of Fig. 4 correspond to the positions of the various parts of the device 31 in Fig. 2. It will be noted that in this condition, both sets of contacts of the emergency release device are open.

Should the elevator operator actuatethe button 49a to the position wherein the end of the button occupies the position represented by the broken line H5, the resulting movement of the plunger |05 actuates the shaft 93 in a counterclockwise direction. During the initial rotation of shaft 93, the cam 9| engages the cam follower 89 to move the bridging contact 63a into bridging relationship relative to its associated contacts 59a and Ela. The continued rotation of shaft 93 finally brings the cam 91 into engagement with its associatedcam follower 99'tomove the bridging contact 43a intobridging relationship relative to its associated fixedv contacts. The cams maybe designed to maintain-both of the bridging contacts 43a and 63a in-bridging-relationship when the end of the button-occupies the position represented by the broken line H5. The resulting positions ofthe parts correspond to the positions of the parts of the emergency release device 31 illustrated in Fig. 3.

The button 49av is maintained' in its intermediate position by means of the member 51; As previously pointed out, the member 57|.4 may take the form of a frangible panel, preferably constructed ofi glass.- The: panel 51 is secured to a control panel-P by means of' suitable machine screws IIT and clipsv H9. It will be understood that the emergencyv release device is located in the elevator car and-that the elevator operator does not' have access to the space between the control panelP and the. base. member |0| until he breaks the frangiible panel 5.1.

In operation it will berecalled'that the bridging member 63A wouldl be connected in` series with the door switches.. Since. this. bridging contact is closed when the button 49c1occupies the intermediate or normal position illustratedin full lines in Fig. 4, it will be appreciated that the elevator operator can operate his `car in a normal manner by manipulation of the car switch 25 (Fig. l). This assumes that the door switches are closed.

Shouldv one of the door switches-be open for any reason, the` elevator operator can operate his car by initially-breaking'the frangible panel 51f izo-expose the button 49a. Upon destruction of the panel51-,the spring promptly moves the button49atoopen.both of the bridging contacts 43afandx63a. Under these -circumstances, the elevaterA operator cannot operate his car;

rllo-'initiate operation of the car, the elevator opcratorf-pressesthebutton 49a-to close both of the bridging contacts 43a and 63a. This permits operation of the car following closure of the car switch 25 but such operation is possible only as long as the operator continues to press the button 49a. Since the continued pressure of the button is tiresome, the operator soon requests replacement of the frangible panel.

Although the invention has been described with reference to certain specic embodiments,

numerous modications lfalling within the spirit and scope of the invention as possible.

Iclaim as my invention: 1 A 1. In an elevator control system, elevator door means, a control circuit including interlocking means responsive to` an opening .operation of the doorv means for interrupting said control circuit., and a rst switch operable independentlyof the vdoor means for interrupting the control circuit,

avsecond switch operable for bypassing the interlocking means and the first switch, and operating means for the switches, said operating means being operable independently of the dcormeans and being operable from a first condition wherein both of said switches are open to a. second condition wherein the rst switch is eiective :for completing the control circuit and wherein the second switch is ineffective for bypassing the interlocking means and the first switch, said operating 4means being operable to a third condition wherein both of the switches are closed. l

2. An elevator control system as dened in claim 1 in combination with means urging said operating means towards thenrst condition, and releasable restraining means for restraining the operating means in the second condition.

3. An elevator control system as dened in claim 2 wherein the restraining means comprises a member having a frangible rportieri in the path of the operating means which may be destroyed readily to release said operating means.

4. In an elevator system, an elevator car having a control panel which Vincludes a' rangible portion, a control unit comprising an operating member separated from the interior of the elevator car by said frangible portion, biasing means yieldably urging said operating member into an intermediate position wherein the operating member engages the frangible portion, said biasingy means being effective upon removal of the frangible portion for urging the operating member through the position normally occupied by the frangible portion towards a released position, said operating member being movable against its bias away from the irangible portion towards an actuated position', said control unit including a rst switch and a second switch responsive to the position ofthe operating member, an elevatordoor including a third switch responsive to the position of the door, a control circuit including said i'lrst and third switches in series, the iirst switch being closed in the intermediate position of the operating member and open in the released position of the operating member, said second switch being open in the released and intermediate positions of the operating member and closed in theactuated position of the operating member, and means controlled by the second switch for bypassing the first and third switches.

5. In an electrical switch device, iirst switch means, second switch means, operating means for the switch means including an operating member operable from a i'irst position wherein bothof the switch means are open, to a second position wherein only one of the switch means is open, said operatingmember beingoperable to a third position wherein both of the switch means are closed, 'means yieldably urging vthe operating member towards the first position, and releasable restraining means restraining said operating member in the second position, said releasable restraining means being releasable for permitting operation of said operating member between said three positions.l

6. An electrical switch device as defined in claim 5 wherein the releasable restraining means comprises a frangible member, said frangible member being readily breakable without damage to the remainder of the switch device to release the operating member.

'7. In an electrical device, a circuit having connected in parallel a normally-closed rst arm and a normally-open second arm, a frangible member, control means responsive to removal of the frangible member for interrupting the normallyclosed arm, said control means including manually operable means accessible only following removal of the frangible member for closing the normally-open arm, and yieldable biasing means for urging the manually operable means to the condition wherein thev second arm is open.

8. In an elevator system, a door control circuit having rst and second arms connected in parallel, a rst switch and a door-operated second switch connected in the first arm, a manuallyoperated third switch connected in the second arm, said switches having open and closed conditions, biasing means urging the rst and third switches into predetermined first conditions, and releasable retaining means for releasably retaining the first switch in a second condition under normal conditions of'operation of the elevator system.

9. A system as claimed in claim 8, wherein the rst switch and second switchv are connected in series in the iirst arm, and the releasable retaining means comprises a frangible glass panel nornally retaining the rst switch in closed condiion.

10. A system as claimed in claim 8, wherein the glass panel until broken prevents operation of the third switch.

11. A switch assembly comprising first and second switches having open conditions and closed conditions, said switches being biased towards open positions, and means including a frangible member preventing access to said switches for changing their conditions, said frangible member being positioned to retain the iirst switch in closed position until the frangible member is removed from its normal position. i

WILLIAM F. EAMES.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS

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