US1896541A - Electromechanical interlock - Google Patents

Description

Feb. 7, 1933. E. L. DUNN ELECTROMECHANIQAL INTERLOCK Filed April 29, 1929 2 SheetsSheet l CONTROL FIG. 3

W Lil Mm INVENTOR ATTORNEY Feb. 7, 1933. E. 1.. DUNN ELECTROMECHANICAL INTERLOCK Filed April 29, 1929 2 Sheets-Sheet 2 @MA L 11%, XNVENTOR ATTORNEY Patented Feb. 7, 1933 UNITED STATES PATENT OFFICE EDVTARD LEE DUNN, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY ELECTROMECHANICAL INTERLOCK Application filed April 29,

The invention relates to interlock mechanism and particularly to electromechanical interlocks for elevator doors.

One feature of the invention is the provision of interlock mechanism of the above character which is of simple yet fool-proof construction and which is positive and reliable in operation.

A second feature of the invention is the provision of magnetically releasable door interlock mechanism which first renders the control circuits ineffective and then unlocks the door.

A third feature of this invention is the provision of a magnetically releasable door interlock which cannot operate to unlock a hatchway door until the elevator car is stopped opposite that door.

A fourth feature of this invention resides in the provision of a system of control for magnetically releasable door interlock mechanism which maintains the interlock mechanism released for a definite time period.

A fifth feature of this invention is the provision of a system of the above character in which the interlock mechanism may be again released after the expiration of the time period.

Other features and advantages will become apparent from the specification and appended claims.

The invention will be described, by way of illustration, as embodied in a full automatic push-button controlled dumbwaiter system utilizing vertically sliding hatchway doors and serving four floors; but it is to be understood that this invention is readily ap plicable to any number of floors, othertypcs of doors, and other types of elevator instal- Iations.

In carryingout the invention, according to the embodiment illustrated, an interlocking bar is secured tothe hatchway door and arranged to move with the door upon the opening and closing thereof. A dctent is positioned in the path of movement of the interlocking bar to obstruct the movement thereof. An operating member for the door contacts of the interlock is arranged to prevent the withdrawal of the detent from its obstructing 1929. Serial No. 359,049.

position when the door contacts are closed, thereby locking the door in its closed position. The door-contact operating member is operated by an electromagnet to effect the separation of the door contacts and to release the detent to permit its movement from its obstructing position, thereby unlocking the door, said detent, upon movement from its obstructing position, assuming a position to prevent actuation of the door-contact operating member to engage. the door contacts, and said detent being maintained in such position Iwhile the door is open by the interlocking In the control system illustrated, as the car is brought to a stop at a floor, the interlock for the hatchway door at that floor is automatically released. The release of the interloek renders the controls ineffective separating the door contacts at that floor. The door is maintained unlocked and the door contacts separated for a predetermined time interval so that a person at that floor has a reasonable time in which to note the presence of the car and open hatchway door. If the hatchway door is not opened, or is reclosed, before the time period expires, the door is automatically relocked and the controls rendered effective by the automatic reengagement of the door contacts. The interlock maybe again released after the time interval has expired in response to a manual control operation, provided the car has not been called to another floor.

In the drawings Figure 1 is a schematic representation of an elevator system embodying the invention;

Figure 2 is a detail view taken along line 22 of Figure 1, illustrating the position of the parts of the interlock when the magnet is deenergized and the hatchway door is closed;

Figure 3 is a detail View taken along line 33 of Figure 1, illustrating the position of the parts of the interlock when the magnet is energized and the hatchway door is open, parts being shown in section; and

Figure 4 is a simplified wiring diagram illustrating a manner in which the invention may be arranged in an elevator control system.

2K to the yoke in such manner as to permit its ber 68 that this endrests on the tread ofthe Referring to Figure 1, a dumbwaiter car 51 is raised and lowered in the hatchway by means of a motor 52. At each of the floors served by the car there is a vertically sliding hatchway door 53. Each door is provided with an electromechanical interlock 5A. As each of these interlocks is of the same construction, only one of them will be described. Ac cording to the embodiment illustrated 1n Figures 2 and 3, a'projecting arm 55 is at tached to the top of the door 53. A yoke 59 is pivotally connected to the outer end of the arm 55. This yoke is connected to a second yoke 57 through the intermediary of a rod 60, nuts being provided at the ends of the rod to. permit adjustment. A bar 56 is supported by the yoke 57, the bar extending between the arms of the yoke and being fastened thereto by a pivot pin 58. The bar is fastened top and surface 61 to engage surface 62 of a detent. 63 upon upward movement of the bar. Detent 63 is pivotally secured to a pair of lugs 64 integral'with an interlock casing 65. Integral with this detent is ring 66 through which bar 56 passes, the ring being so cut that about twenty degrees of rotation of the ring and detent is permissible without hindrance by the bar 56. Ring 66 and the yoke 57 are arranged so that as the yoke descends, the bottom ends of the arms thereof engage the ring and rotate the ring and detent clockwise. In this manner, the detent is rotated so that its surface 62 is positioned over surface 61 of bar 56.

The casing 65 is secured to the hatchway wall and is provided with a suitable cover 69. lVithin the casing there is a magnet with an armature 67, a member 68 rotatably sup ported about pin 70, which is suitably fastened to a lug 71 integral with the casing 65,

and appropriate linkage connections 72 be I tween armature 67 and member 68*. The arrangement is such that the armature is normally displaced from the magnet due to the weight of the parts, but if desired, the armature may be positively biased in the displaced positionby means of compression spring 7 8 placed between the linkage connections and casing 65. V

' Also within casing 65 are door contacts DC comprising two fixed contacts 74 to which the exterior circuits are connected by wires 75 and 7 6,. and two movable contact wiper arms 77 suitably secured to member 68. The latter are arranged to complete the circuit between wires 75 and 76 when the wiper arms are in engagement with contacts 74. This engagement occurs only when magnet M is not energized and member 68 is at its limit of clockwise rotation. Y 7 V The detent 63 is formed with two stepped portions 78 and 79 along its rear edge, soarranged in relationship to the end 80 of anemlower stepped portion 78 when the wiper arms 77 secured to this'member engage the door contacts DC, and on the tread of the upper stepped portion 79 when the wiper arms are disengaged from the door contacts DC. As may be seen in Figure 2, wherein the hatchway door is shown closed, the hatchway door may be moved upwardly only a short distance when the top end surface 61 of bar 56 engages with the surface 62 of the detent and thus tends to rotate the detent counterclockwise. The detent is unable to so rotate, however, due to the engagement of the end 80 of member 68with the riser of the lower stepped portion 78 and so the surface 62 effectively obstructs the upward movement ofthe door. The hatchway door is thereby locked closed, and may be unlocked only by removing the surface 62 from obstructing the upward movement of bar 56. This is in turn only possible by rotating the detent counterclockwise. This movement of the detent is impossible, however, until the member 68 is rotated to withdraw its end 80 from engagement with the riser of the lower stepped portion 78. Such rotation of the member may be obtained by the energization of magnet M which magnet thereupon operates to attract its armature 67 upwardly. and by means of the linkage mechanism 7 2 connecting the armature with the member, to raise the end80 out from the stepped portion 78. The detent may now be rotated counterclockwise, either directly by raising the door, or by means of a compression spring 81 positioned between the interlock cas1ng65 and a portion of the detent if such spr ng is provided. As a result, the surface 62 no longer obstructs the upward movementof bar 56, and hence the hatchway door 53 may be opened. V

It is to benoted that in order to release the detent and thus unlock the hatchway door, member 68 must first be rotated counterclockwise. Since this member 68 has secured thereto the wiper arms 77 for the doorco'nt'acts, these wiper arms are accordingly withdrawn from engagement with the contacts 7 4: to first break the circuit through the wires 75 and 76 before the hatchway door is unlocked. The subsequent counterclockwise rotation of the detent, as outlined above, inserts the treadof the upper step 79 underneath the end 80 of the member 68, thereby preventing clockwise movement of this member and thus preventing any completionof the circuit through the door contacts while the detent is in the doorreleasing position. 7

It is also to be noted that the opening of the door moves the bar 56 upwardly through the ring 66 and past the nose 82 of the detent, but such is the length of the bar 56 thatit is never withdrawn from the ring 66; so that when the hatchway door is fully open, the parts are inthe positions as illustrated in Figure 3.

Clockwise rotation of the detent to the extent of withdrawing the tread of the upper stepped portion 7 9 from underneath the end 80 of the member 68 is then impossible for the detent may be rotated only a small amount before its nose 82 butts against the bar 56 and is thus prevented from rotating farther. It is accordingly impossible to complete the circuit through the door contacts when the hatchway door is in any position other than in its closed position.

Uponmovingthehatchwaydoordownward- 1y from the open position to close the hatch way opening, the bar 56 is lowered through the ring 66 without changing the positions of the other parts of the interlock until the door is almost closed and the bottom ends of the arms of the yoke 57 engage the ring 66. The remaining movement of the door to its closed position causes the rotation of th detent clockwise to the position illustrated in Figure 2, with the nose 82 and surface 62 of the dctent moved into a position over the top endsurface 61 of the bar 56. The tread of the upper stepped portion 79 having been thus removed from under the end 80 of the mem ber 68, the member is rotated clockwise, assuming that the magnet M is now deenergized, by the combined partial weight of the member, the linkage connections 72, and the armature 67, and assisted by the compression spring 73, if provided, until the end 80 rests on the tread of the lower stepped portion 78. In this movement of the member 68 the wiper arms 77 engage with the contacts 7% and c0mplete the circuit through the wires and 7 6. It is to be noted that as member 68 swings about its pivot, its end 80 engages the riser of the lower stepped portion Y8 before the wiper arms 77 engage the door contacts DC. As a result, the circuit through the door contacts is completed only after the hatchway door is closed and locked. The parts are then in the position illustrated in Figure in which, as previously described, the hatchway door is closed and securely locked,

Although the interlock mechanism is shown as having the bar 56 connected to the top of the door, it is to be understood that the bar may be connected to the bottom of the door and arranged to exten d upwardly through the ring 66. In such event, the interlock casing is secured to the hatchway wall at a point such that operation as above described is obtained.

For the purpose of completely describing one manner in which the electromechanical. interlock of this invention may be utilized. there is illustrated in Figure 4 a wiring diagram of the control circuits for a full automatic push-button controlled dumbwaiter system embodying this invention. In this diagram, the electromagnetic switches have been given letters in addition to the usual rcference numerals, so that parts of the same switch may be identified by means of the common letter. The electromagnetic switches are shown in their deenergized positions. The designations of the electromagnetic switches are as follows ML-main line switch, UP--up direction switch, DN-down direction switch, STstopping switch, FSfioor switches,

Hauxiliary door lock switch,

Zhall time limit switch.

In addition to the electromagnetic switches, there are sets of manually operable switches at each floor in the form of push buttons to send and to call the dumbwaiter car. There is a call button identified by the letter C at each floor to call the car to that floor, and a set of send buttons identified by the letter S at each floor to send the car to each of the other floors in the system.

To assist in the understanding of the drawings, control elements that are present for each floor have been so designated that the number in the tens position is indicative of the floor for which the element is operative; thus, FS 16 designates the actuating coil of the floor switch for the first floor, FS 47 'he holding contacts for the floor switch for the fourth floor, contact 131 a third floor contact on the floor selector, C 25 the call button for he second floor and S 34 a send button to send the car to the third floor.

Referring now to the wiring diagram of Figure l, the motor 52 in the embodimen' illus'lra Zed is an alternating current type motor with windings 83 adapted for connection to the three phases I, II and III of the power mains through the main line switch contacts ML 84 and ML 85 and through th reversing switch contacts UP 86 and UP 8'? or DN 88 and DN 89. Across one phase winding of the motor, and adapted to be energized with the energization of the motor, is the brake release coil 90.

In the penthouse with motor 52, as illusrated in Figure 1, there is a floor conroller 91 which in reality a miniature of the car and hatchway. Thatis, there is a block 99 which is moved up and down in proportion to the actual movement of dumbwaiter car 51. This is accomplished by non-rotatably mounting block 92 on a vertical screw 93 which is positively driven from the raction sheave 94 which in turn is positively connect ed to car 51 by means of hoisting tape Secured to the floor controller and mounted vertically one above the other are horizontal rows 96 of contact devices. which other contact devices on the block each row 96 representing a floor in the hatcl They are so spaced with regard to the movement of block that when the elevator car is opposite a floor, the block is opposite the row 96 corresponding thereto.

Returning to Figure 4, there are mo'unted on rows 96 two sets of contacts, 111, 121, 131, 141 and 112, 122, 132, 142. The contacts 111, 121, 131and 141 are in one vertical column, while contacts 112, 122, 132 and 142 are in another vertical column. 'On block 92 there is a Contact or brush 150 which engages with the first set, and two contacts or brushes 151 and 152 which engage with the second set. Also mounted on rows 96 are switches 113, 123, 133, 143 arranged in a vertical column. These switches are controlled by a cam secured to block 92. This cam comprises two elongated end sections 153 and 155 and a center section 154 insulated therefrom.

Since, as previously siated, the system includes'au electromechanical interlock for each floor, the interlocking magnets and the door contacts for he'ile-ors are respectively designated: M 12 and DC 13 for the first floor; M 22 and DC 23 for the second floor; lvl and DC 33 for the third floor; and M 42 and DC 43 for the fourth floor.

In operation, let it be assumed that the car is at the fourth floor, that the hatchway door at that floor is open and that magnet M 42 of theinterlock for that floor is deenergized. The position of the parts of interlock 54 at that floor is shown by Figure 3, previously described. Since the fourth floor door is open, door contacts DC 43 for that door are separated, thereby rendering the control circuits inoperative to move the car. Let it be further assumed that a person at the fourth floor desires to send the car with an article he has placed thereon to the first floor. To do so he first closes the hatchway door and then pushesthe send button S 14 at the fourth floor. It will be recalled from the description of the electromechanical interlock that when the hatchway door is fully closed and locked the circuit through the door contacts at that floor is completed. Hence, the subsequent closing of the send button S 14 completes a circuit from phase I, by way of conductor 156, main line switch contacts ML 99, conductor 162, floor controller contacts 150 and 141, conductor 163, conductor 164, send button S 14 on the fourth floor, resistance 119, first floor switch actuating coil FS 16, floor controller switches 113 and 123, arm of floor controller switch 133, cam section 153, contacts UP 101, conductor 158, down direction switch actuating coil DN 98, conductor 157, and door contacts DC, to phase .11. The actuating coil FS 16 of the first floor switch is thus energized, causing the engagement of contacts FS 17 and FS 18. The purpose of these contacts will be explained later. Simultaneously, the actuating coil DN 98 of the down direction switch is energized, causing the separation of contacts DN and DN 106 and the engagement of contacts DN 88, DN 89, DN 107, DN 108 and DN 109. Contacts DN 105 control the circuit for the actuating coil UP 97 of the up direction switch. Thus, with contacts DN 105 separated, this coil can not be energized. Contacts DN 106 control the circuit for coil H of the auxiliary door lock switch. With contacts DN 106 separated, coil H 135 can not be energized. The engagement of contacts DN 88 and contacts DN 89 prepares the circuit for the motor 52 for starting the car in the down direction. The engagement of contacts DN 109 connects floor controller contact 151, which serves as the down stop brush, to phase II, rendering this contact alive. The engagement of contacts DN 108, together with the engagement of contacts FS 18, connects floor controller contact 112 to phase I, rendering this contact alive. Also, the engagement of contacts DN 108, together with the engagement of contacts FS 17 completes a circuit for coil ML 100 of the main lineswitch. This circuit may be traced from phase I, by way of conductor 128, contacts DN 108, coil ML 100, stop switch contacts ST 116, conductor 161, contacts FS 17, co-ilFS 16,floor controller switches 113 and 123, arm of floor controller switch 133, cam section 153, contacts UP 101, conductor 158, coil DN 98, conductor 157, and door contacts DC, to phase II. It is to be noted that subsequent release of the push button does not result in the dropping outof the main line, down direction, and first floor switches, the actuating coils of these switches being maintained energized by contacts DN 108 and FS 17 The engagement of contacts DN 10? connects the cam section 154 to cam section 153. The purpose of this arrangement will be explained later. It is to be noted that the engagement of contacts DN 107, together with the engagement of contacts DN 108 and FS 17 does not complete a circuit through the coil H 135 of the auxiliary door lock switch due to the separation of contacts DN 106.

The energization of actuating coil ML 100 of the main line switch causes the engagement of contacts ML 84 and ML 85 to energize the motor 52 and the brake release coil 90, and the separation of contacts 14L 99 to render inoperative all the control buttons and thereby prevent interference while the car 7 is proceeding to its destination. The brake is thus released and the motor operated to st-art'the dumbwaiter car downwardly.

As the car descends in the hatchway, the floor controller block 92, mounting the floor controller contacts 150, 151 and 152 and cam sections 153, 154 and 155, descends in a proportionate relationship thereto .overthecontact rows 96. The successive engagement of floor controller contact 1150 with contacts 131 and 121 is of no effect as the contact is dead due to the separation of contacts ML 99. The successive engagement of the cam section 153 with the arms of the floor controller switches 123 and 113 maintains a circuit from actuating coil FS 16 to the actuating coil DN 98 so that the maintaining circuit for these coils and for coil ML 100 is not interrupted. The successive engagement of floor controller contacts 151 and 152 with the stationary contacts 142, 132 and 122 is of no effect as these stationary contacts are dead, due to the separation of contacts FS 48, FS 38 and FS 28 respectively, and as contact 152 is dead, due to the fact that up direction switch contacts UP 110 are separated. The dumbwaiter car therefore continues past the third and second floors without stopping;

Before the dumbwaiter car reaches the first floor hatchway door opening, floor controller contact 152 engages with stationary contact 112. Although contact 112 has been rendered alive by the engagement of contacts FS 18 and contacts DN 108, contact 152 is dead so that no circuit is completed when this engagement occurs. Upon the engagement of floor controller contact 151 with contact 112, a circuit is completed for coil ST 1.15 of the stopping switch. This circuit may be traced from phase'I, by way of conductor 128, contacts DN 108, conductor 138, contacts FS 18, contact 112, contact 151, contacts DN 109, coil ST 115, conductor 157, and door contacts DC, to phase II. The stopping switch, operating as the result of the energization of its coil ST 115, causes the separation of its contacts ST 116 and the engagement of its contacts ST 118. The purpose of contacts ST 118 will be ex lained later. The separation of contacts T 116 breaks the circuit for main line switch coil ML 100, first floor switch coil FS 16 and down direction switch coil DN 98. The first floor switch, returning to deenergized position as a result of the breaking of the circuit for its actuating coil FS 16, causes the separation of its contacts FS 17 and FS 18. The separation of contacts FS 18 is in preparation for a subsequent control operation. Contacts FS 17 are in' the circuit for coils ML 100, FS 16 and DN 98, thiscircuit having previously been broken by the separation of contacts ST 116. The down direction switch, returning to deenergized position as the result ofthe breaking of the circuit for its actuating coil DN 98, causes the separation of contacts DN 88, DN 89, DN 107, DN 108 and DN 109 and the reengagement of contacts DN 105 and DN 106. Contacts DN 105 are in the circuit for coil UP 97 of the up direction switch, the reengagement of these contacts being effective to prepare the circuit for this coil for a subsequent start in the up direction. Contacts DN 106 are in the circuit for coil H 135 of the auxiliary door lock switch, the engagement of these contacts reconnecting this coil to phase II of the power mains. The separation of contacts D1? 107 disconnects the center section 154 of the cam from the lower end section 153. Contacts DN 108 are in the circuit for coils ML 100, F S 16 and DN 98, this circuit having been broken by the separation of stop switch contacts ST 116. The separation of contacts DN 109 renders contact 151 dead. The main line switch returns to deenergized position, as a result of the breaking of the circuit for its coil ML 100, simultaneously with down direction switch DN, causing the separation of its contacts ML 84 and ML 85 and the reengagement of its contacts ML 99. The efi'ect of the reengagement of contacts ML 99 will be explained later. The separation of contacts ML 84 and ML 85, together with the separation of down direction switch contacts DN 88 and DN 89, breaks the circuit for the motor 52 and for the brake re lease coil. The deencrgization of the motor and application of the brake causes the car tlo be brought to a stop opposite the first floor c oor.

As the car approached the first floor door opening, floor controller contact 150 engages with contact 111, preparing the circuit for first floor interlock magnet M 12. This circuit is completed by the engagement of hall time limit switch contacts Z 126 and main line switch contacts ML 99. As previously explained, upon the initiation of the stopping operation, stopping switch ST operates to cause the engagement of its contacts ST 118. The engagement of these contacts causes the energization of the hall time limit switch Z, connecting its coil Z 125 across phases I and II of the power mains. Thereafter, upon the separation of down direction switch contacts DN 108 and DN 109, the circuit for coil ST 115 is broken, permitting the return of the stopping switch to deenergized position. The period of engagement of contacts ST 118, however, is sufficient to cause the operation of switch Z, resulting in the engagement of contacts Z 126 and the separation of contacts Z 127. The engagement of contacts Z 126, together with the reengagement of contacts ML 99 completes the circuit for magnet M 12 of the first floor interlock. This circuit may be traced from phase I, by way of conductor 156, contacts ML 99, conductor 162, floor controller contacts 150 and 111, conductor 114, magnet M 12, conductor 165, and contacts Z 126, to phase II. The energization of magnet M 12 causes the separation of the first floor door contacts DC 13 and the release of the door look, as previously described. Switch Z does not return to its deenergized position immediately upon the breaking of the circuit for its coil Z 125 by the separation of contacts ST 118, its action being delayed for a predetermined time interval as by a dashpot. Accordingly, the hatchway door at the first floor may be opened at any time during the period provided by switch Z.

Contacts Z127 control the circuit leading -t0 thewcall huttons O-atftherfloors. Thus, -a1tho11gh contacts iML-QQ of the main line switch; reengagez during the. stopping.- operagtionnthesepa-ration of contacts Z1 27 main- .tains the circuitto the call buttons open. It 21s; totbe noted; that the engagement of con- ;tacts ML 9 :9.*preparesthe. circuit to the send lonttons KS 4 at the firstffioor. The separation 30f doorcontacts :DC 13,\l1OW6V61,.'Ie 1ClQ1'S call, of. thespusli; buttons dead, preventing the ostarting'ofithe car by a person at the first .efloor, or at any. otherafioor. lfithefirst floor hatchway door is opened during the time in- ;-tenval.provided1by switch Z and maintained 1 openea-fterthistimeinterval hasexpired, the -door contacts DOl8- are maintained separated -mechanically, as previously explained, preeventingthe vstarting. of-the car. If, however, sthe do'or1is returned to closed position before .the expiration of s the time interval or% is :not opened during the interval, the separation :of contacts Z :126 at the expiration of :the :"tilTle period-deenergizes magnet 111 12. Iihe .parts.-of:-theinterlock are then automatically restored to their positions as 'shownin Figure QfitO lock-r thedoor' and effect thereengagement .of door contacts DC :18. Also, at the expiratioriofthetime limit, contacts Z 127 engage, therebyrestoring the call buttons atthefloors and the send bu ttons atothe'first floortovtheir operative conditions. The interval provided ;by,sw it ch Z is of a duration to insure sufficient time for the personat the floor at whieh h .;a ..a i v s t .no t e .a r a and effect .the opening of the door. The actual time provided may -,vary, depending upon the regpiirements of the particular installati A ,Letitbe ass umed, however, that .the hatch -,Way,door;at the firstaloor is opened while the :timel m t wifie m n a s t e act lz 12.6 ngage ndcon q entlyw il thefir fl o hatqhxtay doeri mai tainednnl cked- Ellh dumbwaitercar is :thus maintained under the control of the person atthe ifiISi] :floor. This person may, atter opening zthG .door and removingthe iarticle-trom the ,car, placethereon an article to be delivered-for exampleetothe third floor. Upon/closing thedoor, assuming athatanagnet M 12 is now .deenergized due to the expiration of the time interval, the

.door is looked and door contacts DC 13 re- .engage. After closing the door he momentarily presses th sen hii S at the fi st-floor to ispa ch th :QZH' t0 the th r flopr. resulting sequence of operation oi t e ys em i belie e appar n in View th pre iou de cr pti n of OPBI i D i .ae ordi g y not ec ted i i i be .lieyed strfiicient to note that the third floor sw tc and up dire t wi ch in lve .sead of the first floor w tc and t e down direction witch.- T e third 01' sw tch,

. uponoperat-ion, causes the engagement: of its contactsFSiSB'Zand FS 38, these contacts-cor- ;respending function to i first floor switch contacts ES l7.1aIrd:-FS:l8: respectively. The up direction switch; up on operation, causes s'the separation of; its contacts UPrlOQandUP ilOlnflflCljt'hQ: engagement Of'COl'lbtlCtS U386, 111 87, 2UP 103,1UPz1Q4n1-1d 2UP these [contactscorresponding in :fnnction to down Qdirection switch; contacts :DN 105, 113N106,

:DN =88,EDN: 89,1DN ;10'. ,;D'N;108;.andDN 109 -respectiVe-ly. ;The car proceedsidirectly to the 2 third floor ;Where it ;-isscausedtto be; stopped opposite-theithird'fioor (door byz-thez engage- (iffioor; controllerscontacts 152' and 132.

{lghe :tbird ,fi-oor door ;is automaticallyun- :locked as, the resultgof the engagement of floor icontroller contacts .150 and ,l3lvzanidithe iengagement 1 of 1 main line switch contacts ML :99 and hall imeilimit ssWitchucontactsTZ E126.

:As1bforegthehatchway door is maintained unl cked :and'i'the dumbwaiter controls op rativ iforgatime interval-sufficient to per-' ;niit :pQITSOnsfib the third floor toirespondito signal oncall;announcingrth-e arrivalof the floor. cirouit }is thereby completed from -;phas e1i[,:byw;ay diconduotor l56,"main line switch contacts ML 9.9, contacts {Z 127, call "button C 15 on thefirst'fioor,:resistance 119, Q0il ES 16, switch #113, :arm of switch 123,

ram section l53,.contacts U1? 10.1, conductor 115,8, coiil DN 198, conduct-or 15.7, conductor ljtio ancl door contacts (D6,:to :phase II. The resulting sequence of operation will mot be described ;as it is similar to that previously outlined dorthe dispatchiof-the car from the fourth ito the fi rstflfloor. The car proceeds to the first floor where it is stopped vand ithe hatchrvay gClOQI' atfthat floor unlocked.

lit is tobe noted, however, that although it .is'possibie-to call the 'car to a floor from 0 1.6 of the v attler zfioors, it is not possible to dispatch atheicar except from the floor opposi e which the car is at rest. This is due .to the dependence of the circuits through the nd bnttonsat the 'fioors to the engagement of the contact 3150 with the stationary con- E Q the corresponding floor, and to the independence the circuits through the ,ealgl buttons "to the Contact 150.

It is to ibf 'izurther noted that at any time aiter the expiration of the time interval-and lae fiore the car is called away from the floor pppesite which the car is at rest, a person such floor may himself, by depressing the call button at that floor, seize control of the (delivery is completed and :the T car and cause the unlocking of the hatchway door at that floor. Let it be assumed that the car is at rest at the fourth floor, that the hatchway door at that floor is closed, and that the period of delay for the release of the time limit switch has elapsed. The condition of the circuits is then as illustrated in Figure 4, With the exception that the door contacts DC 43 for the fourth floor are in engagement. Let it be further assumed that the fourth floor call button C 45 is depressed. A circuit for the actuating coil H 135 of the auxiliary door lock switch is completed, the circuit being traceable from phase I, by way of conductor 156, contacts ML 99, contacts Z 127, fourth floor call button C 45, resistance 149, coil FS 46, arm of switch 143, cam section 154, contacts UP 102, coil H 135, contacts DN 106, to phase II. The actuating coil FS 46 of the floor switch and the actuating coil H 135 of the auxiliary door lock switch are accordingly energized. The resulting operation of the former switch is without efi'ect as neither direction switch is energized. The auxiliary door lock switch, however, operates to cause the engagement of contacts H 136, completing the circuit for the actuating coil Z 125 of the hall time limit switch. This switch operates as previously described to unlock the door opposite which the car is at rest, in this case the fourth floor hatchway door, and to maintain that door unlocked and the control system inoperative for the duration of the time interval. It is to be noted that simultaneously with the engagement of contacts H 136, contacts H 137, in parallel with contacts Z 127, become engaged to prevent by the separation of contacts Z 127 a premature breaking of the circuit through the actuating coil H 135.

Attention is directed to the fact that an electric light 145 may be positioned on the dumbwaiter car to illuminate the car and, if so desired, to operate as a signal. The light 145 maybe directly connected across the two phases I and II, subject only to the back contacts ML 99 of the main line switch. When the car is stationary, the contacts ML 99 are in engagement, the circuit through the light is complete, and the light is illuminated. Then the car is in motion, the contacts ML 99 are separated, the circuit through the light is broken, and the light is inoperative. A window may be provided in each hatchway door through which the illumination from the car light may be transmitted when the car is opposite the respective hatchway opening. Inasmuch as the light is lit only when the car is at rest, this illumination therefrom through the window in a hatchway door is a signal that the dumbwaiter car is waiting opposite that door.

As previously described, contacts DN 10? connect the center cam section 154 to end section 153 when the car is travelling in the down direction. Similarly, contacts UP 103 connect the center section to end sect-ion 155 when the car is travelling in the up direction. Thus, as the car approaches the floor at which the stop is to be made, the circuit for maintaining the main line, floor and direction switches operated is transferred from an end cam section to the center section. This arrangement insures the stopping operation being caused by other means, in this case by the engagement of either contact 151 or contact 152 of the floor controller with one of its cooperating stationary contacts.

In this manner, arcing between the end and center cam sections is eliminated, minimizing wear and consequent replacement of the cam and insuring reliable operation of the controller. To insure the engagement of the arms of switches 113, 123, 133 and 143 with the center section before leaving an end section, the slots between the sections may be arranged at an oblique angle.

Although the system has been described as effective to control the circuit for the coils of the main line, floor and direction switches. This switching mechanism may be arranged to be operated mechanically in accordance with car movement to open the circuit for these coils at the proper time. In the event that such mechanism be employed, contacts UP 110 and DN 109 are eliminated, contacts 112, 122, 132 and 142 are narrowed, contact 152 is employed to complete the circuit for coil ST 115 during down operation and contact 151 during up operation, switch ST becomes self-holding subject to contacts UP 104 and DN 108, contacts ST 116 are employed to break the circuit for a controlling magnet for this switching mechanism with this magnetalso subject to contacts UP 104 and DN 108, and contacts operated by this mechanism are arranged in conductor 128 in place of contacts ST 116. Vith such arrangement, any desired number of slow down steps may be obtained in addition to the final stopping step by providing the switching mechanism with several additional pairs of control contacts to control appropriate slow down mechanism and arranged to operate in suitable eequence In the event that such arrangement of steps were provided, the floor controller contacts 151 and 152 would be positioned to effect the energization of coil ST 115 at the proper time. The arrangement shown in Figure 4 is chosen for simplicity of description.

It is to be noted that the construction of the electromechanical interlock shown permits its installation at a point in the hatchway inaccessible to tamperers. Furthermore, the provision of the bar 56 and yoke 57 in front of the interlock casing opening through which detent 63 extends prevents tampering with the mechanism within the interlock casing. The interlock contacts particularly are inaccessible, thus eliminating the possibility of operation of the car with the door open. The interlock is therefore fool-proof in construction. i

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is 1. Interlocking mechanism for an elevator hatchwaydoor comprising; circuit controlling means; a member secured to said door for movement therewith; means movable into the path of movement of said door member to obstruct the movement thereof from its door closed position; and means for closing said circuit controlling means, said last mentioned means acting to secure said obstructing means in its obstructing position when said circuit controlling means is closed, thereby locking the door.

2. Interlocking mechanism for an elevator hatchway door comprising; door contacts; a bar connected to said door for movement therewith; a pivoted member operable to a position to obstruct the movementof said bar from its door closed position; and means for causing the engagement of said contacts, said last named means acting to secure said pivoted member in its obstructing position to lock said door prior to effecting the engagement of said contacts.

3. Interlocking mechanism for an elevator hatchway door comprising; door contacts; an operating member for said contacts; a member for latching said operating member inposition separating said contacts; and a member connected to said door for movement therewith, said door member acting, when the door is open, to prevent movement of said latching member out of latching position, thereby preventing the reengagement of said door contacts.

4. Interlocking mechanism for an elevator hatchway door comprising;'door contacts; an operating member for said door contacts; a pivoted member having a shoulder adapted to engage said operating member, when said operating member is in positlon separating said contacts, to latch said operating member in said position; and a bar connected to said door for movement therewith, said bar cooperating with said pivoted member, when said door is open, to prevent movement thereof out of latching position, thereby preventing the reengagement of said door contacts when the door is open.

5. Interlocking mechanism for an elevator hatchway door comprising; door contacts; an operating member for said contacts; a bar connected to said door for movement therewith; and a pivoted member operable in one position to latch said operating member in a position separating said contacts and operable in another position to obstruct the move ment of said bar when the door is closed, said bar acting, when the door is open, to prevent the movement of said pivoted member out of latching position, thereby preventing the reengagement of said contacts, and said operating member acting, when the door is closed and the door contacts are in engagement, to secure the pivoted member in its position obstructing said bar, thereby locking the door.

6. Interlocking mechanism for an elevator hatchway door comprising; door contacts; an operating member for said contacts; a bar connected to the hatchway door for movement therewith; a pivoted member; means to rotate the pivoted member upon the closing of the door and the corresponding movement of said bar so that a portion of said pivoted member obstructs the reverse movement of said bar; a shoulder on said pivoted member, said operating member engaging said shoulder, when the door contacts are engaged, to secure said pivoted member in said obstructing position, thereby locking said door; means to rotate the pivoted member out of said obstructing position to another-position when the operating member is moved to separate said contacts; and a second shoulder on said pivoted member adapted, when said pivoted member is in said other position, to prevent movement of said operating member to engage the door contacts, said bar acting, when the door is open, to prevent movement of said pivoted member out of its position obstructing the return movement of said operating member, thereby maintaining said contacts separated.

7. Interlocking mechanism for an elevator hatchway door comprising; a member connected to said door for movement therewith; a latch member for obstructing the movement of said door member from door closed position; an electromagnet; an armature for said magnet; means connected to said armature for movement therewith, said means, when the magnet is deenergized, being adapted to secure said latch member in its obstructing position, thereby locking the door, and being moved by said armature, when said magnet is energized, to release said latch member,

thereby unlocking the door; and circuit con-.

trolling means operated by said securing means.

8. Interlocking mechanism for an elevator hatchway door comprising; an electromagnet; an armature for said electromagnet; door contacts; an operating member for said door contacts connected to said armature for operation thereby, said armature, upon energization of said electromagnet, being attracted thereby to operate said operating member to a position separating said contacts; a pivoted member cooperating with said operating member, when said operating member is moved to said position, to latch said contacts in separated position; a bar connected to said door for movement therewith, said bar acting when the door is open, to prevent movement of said pivoted member out of latching position; and means for moving said pivoted member out of said latching position, upon closing said door, into a position to obstruct the movement of said bar from door closed position, said operating member returning to position to effect the reengagement of said contacts, upon deenergization of said electromagnet, and being adapted to secure said pivoted member in said obstructing position to lock said door during said return movement prior to effecting the reengagement of said contacts.

9. In an elevator system in which the elevator car is adapted to serve a plurality of floors and in which a hatchway door is provided at each floor; locking mechanism for each door comprising, a door lock, releasing means for said lock, and an electromagnet for said releasing means, said electromagnet being adapted, upon energization, to operate said releasing means to release said lock; means operable during the stopping of the car at any one of said floors to cause the energization of the electromagnet of the looking mechanism for the door at that floor; and means operable upon the expiration of a predetermined time interval after the energization of said electromagnet to cause the deenergization thereof.

10. In an elevator system in which the elevator car is adapted to serve a plurality of floors and in which a hatchway door is provided at each floor; locking mechanism for each door comprising, a door lock, releasing means for said lock, and an electromagnet for said releasing means, said electromagnet being adapted, upon energization, to operate said releasing means to release said lock; means operable during the stopping of the car at any one of said floors to cause the energization of the electromagnet of the locking mechanism for the door at that floor; and means operable upon the expiration of a predetermined time interval after the initiation of said stopping operation to cause the deenergization of said electromagnet.

11. In an elevator system in which the elevator car is adapted to serve a plurality of floors and in which a hatchway door is provided at each floor; locking mechanism for each door comprising, a door lock, releasing means for said. lock, and an electromagnet for said releasing means, said electromagnet being adapted, upon energization, to operate said releasing means to release said lock; means operable during the stopping of the car at any one of said floors to cause the energization of the electromagnet of the locking mechanism for the door at that floor; means operable upon the expiration of a predetermined time interval after the energization of said electroinagnet to cause the deenergization thereof; a manually operable control device for each of said floors for controlling the operation of said car; and means responsive to the operation of the control device for any one of the floors at which the car is positioned for causing the reenergization of the magnet of the locking mechanism for the door for that floor after such magnet has become deenergized due to the expiration of said time interval.

12. In an elevator system in which the elevator car is adapted to serve a plurality of floors and in which a hatchway door is provided at each floor; locking mechanism for each door comprising, a door lock, releasing means for said lock, and an electromagnet for said releasing means, said electromagnet being adapted, upon energization, to operate said releasing means to release said lock; means operable during the stopping of the car at any one of said floors to cause the energization of the electromagnet of the locking mechanism for the door at that floor, thereby unlocking said door; means operable upon the expiration of a predetermined time interval after the energization of said electromagnet to cause the deenergization thereof, permitting the locking of said door, if closed, by its door lock; a push button at each of said floors operable to call the car to that floor from any of the other floors; and means responsive to the operation of the push button at the floor at which the car is stopped for causing the reenergization of the magnet of the locking mechanism for the door at that floor after such door has become locked due to deenergization of that magnet, thereby reunlocking the door.

13. In an elevator system in which the elevator car is adapted to serve a plurality of floors and in which a hatchway door is provided at each floor; interlocking mechanism for each door comprising, a door lock, door contacts, and an electromagnet, said electromagnet being adapted upon energization to cause the separation of said contacts and the release of said lock; means operable during stopping of the car at any one of said floors to cause the energization of the electromagnet of the interlocking mechanism for the doorat that floor; and a control device for each of said floors for controlling the operation of said car, any of said door contacts,-

when separated, rendering said control devices ineiiective.

14. In an elevator system in which the elevator car is adapted to serve a plurality of floors and in which a hatchway door is provided at each floor; interlocking mechanism for each door comprising a door lock, door contacts, and an electromagnet, said electromagnet being adapted upon energization to cause the separation of said contacts and the release of said lock; means operable during stopping of the car at any one of said floors to cause the energization of the electromagnet of the interlocking'mechanism for the door at that floor, thereby separating the door contacts of that mechanism and unlocking said door; means operable uponthe expiration of a predetermined tlme interval after the energization of said electromagnet to cause the deenergization thereof, permit ting the locking of said door and the reengagement of said door contacts, provided said door is closed; a push button at each of said floors, each button being operable to call the car to the floor at which it is located from any of the other floors, any of said door contacts, when separated, rendering said push buttons ineffective; and means responsive to the operation of the push button at the floor at which the car is stopped for causing the reenergization of the magnet of the interlocking mechanism for the door at that floor 7 after such door has become locked and the door contacts of said mechanism reengaged due to the deenergization of such magnet, thereby reunl cking the door and separating said door contacts.

15. In an elevator system; a circuit for causing up car travel; a circuit for causing down car travel; a travelling cam operable in accordance'with car movement, said cam having an end section connected to said up car travel circuit, another end section connected to said down car travel circuit and a section intermediate said end sections and insulated therefrom; means for connecting said intermediate section to said up car travel circuit during up car travel; and means for connecting said intermediate section to said down car travel circuit during down car travel.

16. In an elevator system in which the elevator car serves a plurality of floors, a plurality of stationary switches, one for each floor, each of said switches having a member engageable by a movable contacting means to-open such switch and to close a circuit to the movablecontacting means by way of such member; contacting means movablein accordance with car movement r i 7 u i I I for engaging said members of said swltches,

said contacting means comprising two end contacting sections and an intermediate contacting section insulated from said end sections, each of said switches being positioned so that the number thereof engages said intermediate section when the car is opposite the fioor for which thatswitch is provided; a circuit-for causing up car travel connected to one of said end sections; a circuit for causing down car travel connected to the other end section, means for connecting said one end section to the intermediate section during up car travel; and means for connecting said other end section to the intermediate section during down car travel.

17. An elevator system comprising; an elevator car;-a plurality offioors; a switch for each of said floors, said switches being connected in series relation and being spaced to correspond with the distance between their respective floors, and each of said switches having a member engageable by a travelling cam to open such switch; a switch for causing up car travel, said up switch having an actuating coil; a switch for causing down car travel, said down switch having an actuating coil; a travelling cam actuatable in accordance with car movement for successively engaging safd members of said first named switches, said cam having an up contacting section connected to the up switch actuating coil, a-down contacting section connected to the down switch actuating coil and a contacting section intermediate said up and down sections and insulated therefrom, and said cam being arranged so that with the car stopped at a floor the insulated section engages the member of that one of the first named switches thatcorresponds to that floor means for causing said insulated section to be connected to saidupswitch actuating coil during up car travel; and means for causing said insulated section to be connected to said down switch actuating coil during down car travel.

18. In an elevator system; an elevator car; a plurality of floors served by said car; a manually operable control device for each of said floors; a floor switch for each control device adapted to be energized thereby; an up switch for causing up car travel, said up switch having a coil; a down switch for causing down car travel, said down switch having a coil; a stationary switch for each fioor, each comprising a stationary contact and a pivoted contacting operating member for engaging the stationary contact, said stationary switchesbeing connected in series relation with the stationary contact of the switch for the upper terminal floor connected to the coil of the up switch and being spaced to correspond to the distances between their respective floors, each of said floor switches having contacts connected to the contacting operating member of the stationary switch for the floor for which the floor switch is provided; a

travelling cam for successively engaging said contacting operating members to cause their separation from their respective stationary contacts, said cam having an up contacting section connected to the coil of the up switch, a down contacting section connected to the coil of the down switch and a contacting section intermediate said up and down contacting sections and insulated therefrom, said cam being of a length and arranged so that with the car at rest at an intermediate floor the insulated section engages the contacting operating member of the stationary switch for that floor, causing that switch to be open and isolated from the others, the up contacting section engages the contactin operating member of the stationary switch or the floor next above, causing that switch to be open, but connecting its contacting operating member to the coil of the up switch, and the down contacting section engages the contacting member of the stationary switch for the floor next below, causing that switch to be open but connecting its contacting operating mem i ber to the coil of the down switch; mechanism for causing movement of said cam in accordance with the movement of the car; contacts controlled by said up switch for connecting said insulated section to the coil of said up switch during up car travel; and contacts controlled by said down switch for connecting said insulated section to the coil of said down switch during down car travel.

In testimony whereof, I have signed by name to this specification.

EDWARD LEE DUNN.

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