US1860333A - Closure operating mechanism - Google Patents

Description

May'24, 1932.

E. DUNN CLOSURE OPERATING MECHANISM 2 Sheets-Sheet l Filed April 18. 1929 MQ QA ,9

. ATTORNEY Patented May 24, 1932 entree stare ED'WARD ear LEE noun/or nas'ronnnen; new JnaseY, essrenon To OTIS nnnvaron COMPANY, on NEW YORK, N. Y., A oonronarron or new JERSEY onosoan orn'earznc- MECHANISM Application filed April 18, 1929. Serial l lo. 356,052.

The invention relates to closure operating mechanism and particularly to operating mechanism for elevator car gates or'hatchway doors. i

- It is advantageous in certain types of elevator installations to providemechanism for automatically operating the elevator car gate and hatchway doors, particularly incases where these closures must be frequently operated' and in cases Where their manual operation is inconvenient. It is also of advantage to provide mechanism for automaticalpassengers themselves and whereinja ClO- sure must be in closed position before the car may be operated, itis particularly desirable that operatingmechanism he providedfor moving the closure to closed position in order that the car may be operated from any point.

One feature of the inventionis' the pro-' vision of mechanism for operating aclosure to one of its operated positions which oflers a minimum of resistance? to the operation of the closure to its other operated position.

Another feature of the invention is the provision of mechanism for operating a closure to one of its operated positions which offers a minimum of resistance to the manual movement of the closure to such position;

A third feature of the invention is the pro.- vision of mechanismfor operating a closure to one of its operated positions which is adapted to maintain the closure in any position to whichit is moved. T a j A fourth feature of theinvention is the provision of closure operatingmechanism which may beadjusted to cause the closure'to automatically return slowly to' closed position when released.

A fifth feature of the invention is the 'provision of closure operating mechanism which, when adjusted to effect the automatic slow return of'the closure to closedposition', isoperable to accelerate the closing operation;v

A sixth fealture'of the invention is the provision of closure operating mechamsm which is of simple and' rugged construction' and V which is reliable in operation. a

Other features andxad'vantages will become apparent from the following description and appended claims. a I I a The closure operating mechanism will be described by way of illustrationyas applied to the gateof an elevator'car.

In the drawings -i Figure 1 is a front elevation of a portion of an elevator car showing-closure operating mechanism embodying the invention applied LO the car gate; a v 1 Figure 2 is a view, partly in section, showing details of the closure operating mechanism as seen fromthc right o-f Figurelg i 1 Figure 3 1s an enlargeo sectlon, partly broken away, taken along'the line 3- 3 of Figure 1 showing the construction of the closure operating mechanism;

Figure 4 is a sectional view line 4t4:of Figure showing the mannerin which the valve of the closure operating mechanism is guided; and 1 p Figuree is a diagram of the control "encuits of an automatic push buttonel'cva-tor system illustrating the adaptation of the closure operating mechanism to" such an 1 installlation. I, V 3 I 3 In Figure 1 the reference character 21in!- dicates an elevator carwhile the reference taken along the character 22 indicates the car gate which'is illustrated as of the col-lapsilole'type. The

gate isarrangedto be manually opened ash-y the grasp23, it'being understood that a grasp may be provided for operating the gate from both inside andoutside the car, The gate is adapted to y be returned to closed position, when o pemby th'e' closure operating mechanism o'fthe present invention, designated as a whole by numeral 24 and he' ei nafter-re;

' ferred to as the gate closing device.

In the illustrated embodiment of the inven tion, the gate closing device-comprises a:tu;-.

bularcasingmade" up oftwo sections2'5 and 26 of pipe or tubing connected to each other bya coupling 27. The casing is securedto the side of the'elevator car 21 by ring clamps Y pled together.

'28 or other suitablesupports. Prior to joinder of sections and 26 a piston guide 30 is inserted in the section 25 in such manner that a'flange 31 thereonjfits in a counterb'ore 32 on section 25 and the lower end of the piston guide restsupon a portion of the end of section 26 when the sections 25 and 26 are cou- The piston guide 30 extends upwardly into section 25 and a hollow piston cylinder 33 secured in a recess' in the lower end of piston guide 30 extends downwardly in the section '26to a point near the lower end Y 7 thereof. Thelower end of section 26 of the casing is provided witha cap 34-having an opening closed by a plug 35 through which an adjusting screw 36 is threaded. The screw 36 is secured in place by a lock nut 37 thereon.

The cap 34 and its related parts define the lowerend of a chamber 38 in section 26 and afford a liquid tight closure therefor.

A member 40 is secured to the lower end of cylinder 33 and has a port 41 therein aifording a passage from the interior of cylinder 33 to the chamber 38. A valve seat 42 is formed in the member 40 at the upper end of port 41 for cooperation with a check valve 43 adapted to. close the port 41. The valve'43 has a stem 44 which is guided by projections 45 thereon in member 40. and extends downwardly in chamber 38 to a point directly above the adjusting screw 36. .Ariser tube 46 on section 26 serves as a conduit through which oil, glycerin or other suitable non-compressible liquidsmay be in-.

troduced into chamber 38 of section 26 where the liquid rises until it normally 'fills chamber 38 to a height level withthe top of the riser itube. Also'a portion of the liquid passes through port 41 into cylinder 33 around valve 43. cap 47 normally closes the riser tube.

' The piston guide 30 has a central opening 50, provided with-spaced oil baffles 51. which 7 forms the guide for a hollow vertically recip- 'ro cablepiston 48. 'The lower end of the piston 48 is closed and the upper end thereof is interiorally threaded to receive a plug 52 having a flange 53, resting on the upper end 1y fitted in piston guide 30 so that when the piston is in its upper position its weight tends V 'to-cause it to descend in cylinder 33. The

descent of the piston is normally-prevented by the liquid entrapped in cylinder 33 by closed check valve 43. i

r The cable 55 passes through a central opening in a cap 61. This cap is adjustably secured to the upper end of section 25 by a set screw 62 and has a pin 63 extending into the interior thereof for cooperation with a longitudinal slot 58 in the end of section 25.

With .such arrangement, the cap 61 maybe adjusted to align an opening 64 therein with a passage 65 in. piston guide 30. When so Jadjusted,'the cap is locked in position on section 25 by the set screw 62. 7

- The cable 55 extends upwardly over a pulley 66 j ournalled on a pin 67 in a pulley guard and support 68 on cap 61. The cable 55 extends from thepulley 66 towards gate and the free end of'the cable is attached to an upright bar 70 of the gate 22 by a coupling screw 71. This screw has an adj usting nut72 at each side of bar 7 0; The piston 48 and counterweight 56, when in their lowermost position in piston cylinder'33, maintain the gate 22 in its closed position through cable 55. The counterweight 56 is not su'fliciently heavy to alone cause the car gate 22 to move to closed position but serves to maintain the gate in the position to which it is moved and to take up the slack in cable 55.

A magnet-88 is provided for efl'ecting the closing of the gate, this magnet being arranged to lift the check valve '43from its.

seat through the intermediary of a lever 76.

I A clamp ring 7 31's securedabout a shank 74 on the member '40 and has projecting bifurcations 75 between which the lever 76 -is pivoted at 77.- The lever 7 6passes through aslot 80 in the valve stem 44 and'has aJrod 78 attached to its other end." The rod 78 extends upwardly in chamber 38 through the passage 65 in the flange 31 'ofpiston guide,

30 and through the hole64 in cap 61 aligned with passage 65. The rod 78 may be laterally adjusted to a position in alignment with'the passage 65 in piston guide 30 by adjustment of clamp ring 73. A'coupling 81' on the end of rod 78 secures it to a link 82 pivoted .toan arm 83 of'a bell crank. The coupling 81' permits adjustment of the lever 76 within the slot 80. The bell crank is mounted on a bracket'84 fastenedto a plate 85 secured to an extension 89 of the cap 61. The other arm'86 of the bell crank s1 1pports the arma- 'ture 87 of the magnet 88 whose coil is mounted on the bracket 84. p

In operation, the car gate22 maybemanually opened-by means of the grasp .23. As 7 the gate 22 is moved to open. position the counterweight 56 is raised through cable 55 and the piston 48 "is carried therewith through contact of the upper end of the counterweightand the inner surface 57 of plug 52; As piston 48;moves upwardly, suction is produced in the piston cylinder 33 causing the check valve 43 to'be raised off the valve seat 42. 'This permits the liquid from cham! ber 38 to pass through port 41 into cylinder lowering the liquid level in chamber 38. When the upward motion of piston 48 stops,

33 acting on valve 43 closes the port 41. The liquid in the piston cylinder is thus enthe pressure of the liquid in piston cylinder trapped to: prevent it: from QW IlgZ QkA l O chamber-38-as would 'occurif; valve 43- re;

ma n dopen. g t

Th ga e, 2; em i s n h pos t on to which it hasbeen moved asthe piston 484's supportedf'by the liquid entrapped in piston cylinder 33; and cann'ot descend, to close the gate until the valve 43 is raised Upon-energization of: magnet '88 toefiect the closingof; the gate, the armature 87., ofthemagnet; is attracted, rocking-the arm 830i the bell crank clockwiseto lift 120(178, B06118 moves lever 76 clockwise about itspivot'YfTi and-the lever ZG -engagesthe upper end of slot80 in the valve, stem 44, causing the check: valve 43 to be littedoffvalve-seat 42. VVhenthe valve 43, is lifted offvalve' seat 42, the liquid entrapped in piston cylinder 33 passes therefrom througlrport 41 into chamber 38. As piston 48 is no longer supported in its upper position by, the-liquid it adds its weight to that of thecounterweight 56, these-bodies descending to move the gate :22 toy-closed position. As the liquid-escapes from cylinder 33, itopposesthe freedescent ofpiston 48 and thus regulates thespeed at which the gate closes. This speed may be variedby adjuste ing the positionot lever, 76 within slot 80.

The. gate closing device. may be arranged to automatically return the gate to closed position. To obtain suchoperation', thescrew 36lisadjusted-to raisethevalve stem 44 sufficiently, to normally maintain the face of valve 43" a slightvdis't-anceabove theseat 42. The gate closing devicethen functions astollows: When-thegate22 is movedlto open pot-1 sit-ion the counterweight 56 and piston 48 are moved upwardly in piston cylinder 33 through. cable 55. As. piston. 48 moves upwardly, the resultant difference in pressure between the chamber 38 andrthe piston cylinder33causesthe check valvei43-to move upwardly increasing; the opening between the face of check valve? 43; and valve seat 42.

Liquid then passes fromchamber 38 through v port 41 into pistoncylinder 33 until the up; ward motionf piston 48 ceases. 'VVhenthe upwardmotion of piston 48 ceases,the valve 43 descends to its lowerposition with the valve face slightly above valve seat 42. When thecargateQQ is released, the piston 48 and counterweight 56 descend, acting through cable gt0 move the gate 22-to closedposition-.,' The closing-speed of thegate is determined by the rate at whichthe liquid passes from'cylinder 33'to chamber 38,this. in turn being'governed by the, distance; of the-check V valve43from itsseat, By turning adjusting screw36, the valvemay be raised-or lowered,

- thus negulatingthe size of the opening be tween thevalve=43and its seat 42'and there fore the speed at whichothe gateis; closed. With, this arrangemenhvupon energization of magnet: 88 the check valve 43, is lit-tech to increasethe clearance between valve 43 andgseat 42,;permitting the liquid; to escapemore rap; idly from'cylinder 33 to chamber 38, Thusitythe car gate, 22 has been; released; and, is

automatically; closing at a slow rate, theien ergization ofmagnet 88 zaccelerates the clos;

ing operation;

The gate may be closedmanuallythrough;

gr-aspy23; The gate closing device ofi'ers no resistance tothe manual closingof the-gate inasmuch as the counterweight 56 is free; to

descend in piston 48. 4 Thus, the manua1 clos-.,- ing-operation may be performed at any-desired speed. Furthermore as the counter; weightacts to aid the closing operation, the, manual closing may be done with very little efiorh When the check valve 43 is adjusted for automatic closing, the piston follows thecounterweight in the manual closing operation, the speed with which the pistonv dee scends being dependent upon the amount ofpiston continues its descent afterthe gate is 86' clearance between V valve 43 and itsseat.

fully clo-seduntil the inner surface ofaplug 52,

engages the upper end oir'the counterweight. When. the gate operating deviceiis-arranged to maintain the gate inopen position until closing operation. Upon energization of the magnet 88 to raise the: check: valve, however, the piston descends until the inner surfaceofw plug '52 engages the top of the counter-weight.

The adaptation ofthe gate closing device of'the present invention to an automatic push" button elevator system is illustrated in Fig-v ure 5. i It willbe assumedthat the valve-43 of the gate closing device isset to; maintain the gate in the open position. to whichavit is moved and that each hatchway door-is arranged to close automatically whenreleased;

-magnet.88 is energized, the piston .48 (remains in its upper position during the manual For-convenience, a. four, floor installation ils shown,

The various electromagnetic switches em;

these letters, in addition to the usual! refer-g ence numerals, will be applied to theparts of:

the above enumerated switches; For eXam plecontacts K143 are contacts on-the [none interference switch, hile actuating coil; A

120 is the coil that operates the up direction switch. I Y

' The elevator car is raised and loweredjby a motor,'designated as a Whole by 90, which for convenience is illustrated as of the direct The armature of-th-e elevator current type. motor 90 is designated 91, its starting resistmice 92, its series field winding 93 and its separately excited field winding'94.

provided for each door, these contacts beingarranged in series relation and are represented by asingle pair of contacts designated- 101 The door lock contacts are closed only when their respective doors are closed and locked while the auxiliary door contacts are closed whenever their respective doors are closed, even though the doors are not locked.

. Door lock contacts 100- are provided to preventxthe operation of the elevator car except when all h aitchway doors are closed and locked. The purpose of the auxiliary 'doo'r contacts 101 will be seen as the description proceeds. A retiring cam is provided .to con trol the door locks, only-the actuatingmag-- net'98 for the cam being'illustrated. Two

pairs of gate contacts 106 are provided,'these contacts being arranged in the circuit for the actuating coil P 105 of the potential switch.

A push button 104 for each floor is pro vided in the car, these buttons to'be hereinafter referred toas car buttons. Also, a push but-' ton 103 is provided at each floor, these buttons to'be hereinafter referred to-as hall buttons.

A floor controller isprovided, this i mechanism being designated as a whole as 1 107 and comprising contacts 114, 115, 116 and 117 for the intermediate floors and terminal switches 118 and 119 for the top and'bot'tom floors respectively. .A stop switch 108 is provided in the car. .The various safety devices, such as final limit switches, car safety operated switch, governor operated switch, areindicated generally at 109. The service switch for connecting the system .to a suitable power source is indicated at 99.

Assume that the elevator car is at the third 'flo'or andthat the car gate 22 is in open position with the gate contacts 106 separated. Assume further that all the hatchwaydoors are closed and that all hatchway doors, except that at the third floor Where the elevator .car is positioned, are locked in closed position with their related door lock contacts 100 engaged. The auxiliarydoor contacts 101 associated "with all the hatchway doors including that at the third floor are engaged. The above described condition of the car gate contacts :10 6,the doorcontacts 100, auxiliary door contacts 101, as well as the condition ofthe contacts and terminal switches of the floor controller 107 when the car is at the third floor, is that illustrated in Figure 5. When relay T becomes'energized, since auxiliary door contacts 101 are'engaged, and"the contacts T 146 separate. The circuit for coil T 140 may be traced from the positive main,

through the left-hand'blade of service switch 99, wire 180, wire 188, auxiliary door contacts 101, contacts H' 163, coil T 140, contacts K 142, wire 186, the right-hand blade of switch 99, to the negative main. The purpose of relay T will be described hereinafter.

.70 the: service switch 99 is closed coil T 140 of A prospective passenger at the fourth floor desiring to use the elevator car operatesthe hall button 103 at the fourth floor. As a result, coil J102 of the retiringcani switch is energized, causingcontacts 17 Oto engage. The circuit for coil J 102 may betraced'from line 180, through wire181, safety devices 109 7 stop button 108, coil J 102,1wire'182, coil '53 113 of the fourth floor switch, wire 183, fourth floor hall button 103, Wire 184, 'hallbreaking switchcontacts'l 158,' time limit hall breaking switch contactsV 147 wire'185, non-in terference switch contacts K 149, to wire 186. The engagement of contac'tsJ 170completes the circuit for retiring cam magnet 98 and pr'eparesthe circuits for gateIclosing magnet 88.;and'actuating coil P 105 of the'potenti al switch P. The circuit for retiring cam magnet'98 may be traced from wire 180, through vwire 171, contacts J 170, wire 1 72, magnet 98,.to wire 186. Upon energization of retiring? cam magnet 98, the retiring cam isoperated to effect thlocking of the hatchway door at the tird fioor and the engagement of its related door contacts. 1.0 V v Coil S 113 ,which' effects the engagement of floor switch contacts S 166 which corre'; spond to the fourth "floor is in the above traced circuit for coil'J 102'and therefore is also energizedupon operation of the fourth floor hall button. gizat-ion causes the engagement "of floor switch contacts S 166; The engagement of contactsS 166, together with the engagement of door lock contacts 100, establishes The coil S 113 upon enera circuit for actuating coil A oftheup direction switch and actuating coil K 141 of thenon interference switch. This circuit is from line 180,'through wire .181,safetyf'devices 109, stop button 108, coil T102, wire 182, coil S113, floor switch cont'acjt'sfS 166,

Wire 175, terminal switch 118 of fioorcontroller,,107,1 coil A 120, wire 176,,1 151; contacts B 131 of down direction switch '.B,Wire 17 7 actuating coil K141 of the: non-interfere encefswitch K, wire 178, door lock contacts 100 which 7 are now engaged as a result of the operation of theretiring cam, to line 186... As the circuit'for coils J 102 and S 113 is com nose-ass plete'd through the hall button-contacts ;on operation of hall button "103 the coils are consequently energized only during :the 11111381 1 341 the :hall button is pressed. However, these coils are maintained; energized, after the buttoniis released, throughthe"circuit above traced due to the engagement of self-holding contacts S 166 otzthe tourthfloor switch.

vAs coil "K1 11 isenergized, the non-inter.- ference-switch contacts K 149 separate to int'errupt the "circuit 'ofthe ehall buttons T103 and carbuttons 104. Thus, theoperation'of other hall buttons 103does not interterewith the-tripofthe car'tothe fourthfloor, thin-X- iliary contacts K 142 also separate,.rdeenergizing coil, T 1-10. Upon deenergizationof coil T 140, switch contacts T 1416 engage, energizing the actuating coil V 144x01? time limit -hall Ibreaking switch contacts 147. The circuitofcoil V 144 is 'from Wire 180, through Wire 167, contacts T 146 and coil V 1 14:, .to wire 186. The coil V 14 1 upon'energi'zation separates time limit T hall breaking switch contacts V 147. The separation of contacts V 147 establishes-an.additionalbreak in the circuitatohall buttons 103. The purpose 0f this arrangement 'WLlll r-be seen:as the description proceeds. *Energization of *coil K 141 also engagesthe contacts K 143,0om-

'pleting 11118011131111? for gate closing magnet 88 prepared bycontacts J 51 70. Thiscircuit maybe traced from wire 180,,through- Wire 171, contacts J 170, magnet :88, wire 173,. con tacts K 143, fOfWlIQ 186. The magnet .88,

upon energization, lifts the valve tEiandthe gate closing device starts to move .the .car gate *to closed position ":as previously described. The "actuating coil K 1 11 of the non-interference switch is made subject to thedoor lock contacts 100 to *prevent the en gageme'nt of 1 contacts :K V 1%13 to l energize the gate inagnet 88 prior to the locking "of the hatchway door. 1 Thus, the i possibility v of ;-a person openingithehatchway door and being struckbythe-closing gateis obviated.

Theeup-direction switch A- operates sin1ultaneously with non interit'erence switch xK, causing the separation of :its contacts A121 and-A 123, and the engagement of its contacts a .122, A121,.A 126 and A128. irhe separation of contacts A 121 opens the circuit for actuating coil B 1300f the down-direction switch, these contactsnand the correspondingcontactsiB 131 of the down-dined tion switch serving as electrical interlocks. The separation of: contacts 1123 in ire .206 disconnects dynamicbrake resistance 971mm acrossthcrarmature 91- ofelevator motor 90. Theengagementof contacts A -12 land A 126 connects acceleratingswitch coil-C 156across theiele'vator motorfarinature 01, The circuit 1 01 eo'ilaC 5156' may" be traced front the i right hand armature brush,-;through Wire 201, back contactsBsl ii andhold-dojvvn coil B. 135 of the down direction switch 1B, ivvirez 201, Wire '1 150, to Wire 186.

202, contacts A .124, Wire;203,wire;204,\coil ov 206, tothe left hand armaturebrush. The

. engagement of contacts A122 and A126 pre 156, Wire'204, :Wire;205 contacts A 126,2Wi116 T tential switch, uponoperatiomcauses the-engageinent of contacts P150, P 15lrand P152. To reduce currentconsumption, thecircuitof gate inagnet-88 may be arranged to-be opened when the gate reaches ,ClQsed i position. For this purpose auxiliary contacts adapted to separate as the potential'switch P closes-nor auxiliary gate contacts adapted-to separate'as the gate reaches closed gPOSLllilOlI, may insertedin the circuit ofthegate magnet; The

engagementof contacts 1P 1.150 and R151 t completes athe circuits .for the armature 1.91 v

and separately excited field'winding 94. The

circuit, for armature 591 is "from =Wire 180,

through contacts P 151, series field, Winding '93, starting resistance 92,.Wire 204-, Wire205,

contacts A :126,-wire 206, armature 91, Wire 201, contacts B 133, hold-down coil ;B 135, Wire 202,; contacts A122,- wire 187, contacts Hol'd down coil -13 ;13'5 maintains the contacts 13 1'33 firmly engaged. The circuit for the separately excited field Winding 94: is from wire-180, through contacts *P 1'51,W1I8 207,; Wire.- 208, winding 91, Wire 210', cont-acts A 21248, 'g-wi're .21-1, the left half of dynamicbrake resistance 97,-Wire 202,. contacts A 122, W1IB'187, contacts P150, to

wire l86. Theengagementofcontacts l V 150,- P 151-:and ;P 152 completesthe circuit for brake release coil ,The ,circuit -%fQ1-- brake release coil 95 is-from -Wil6f180,;tl11'011gh contact-s1 E151,wvire.-207,- contacts P l52, W136 212, coil '95, by -vvayot wirez210- to Wire/18.6 as'traced for field-Winding 9 1.

motor startsthe car in theupdirectiongiii is the counter E. M. ofthe inotor'ibui-ldsiup,

the coil C =156causestheengagement Iii-C011 tacts C 153,6 15 1 and C insuccessioirto short circuit the starting ,resistance -92iand series field Winding 93rinsteps. .As a'result, the elevator motor is broughtupto full speed.

As the car leaves ,the :third flo'or, the intermediate switch contacts ;115-,of the,floor-con troller l07 Kare engaged '130 enable the, car .to o

return 'tothe third floor.

V i 115 V V Theelevatorvmotorarmature,and separate I g gement, prepare the common circuit I i tVVhen the car nears the fourth'floor, the "terminal switch 118 of controller 107 opens interrupting the circuit of retiring cam switch c011 .1102, 0011 S 113' of floor switch S,

coil A of up direction switchA and noninterference switch coil K 141. Upon deen-c ergization of coil S 113, the floor switch COD. tacts S 166 separate'in preparation for a'subsequent operation. The deenergization of coil A 120 results in the separation of contacts A 122,A 124, A 126 and A 128 and the reengagement of contacts A 121' and A 123. The engagement of contacts A 121 prepares the circuitfor actuating coil B ofdown direction-switch B for a subsequent operation. The engagement of contacts A 123 connects tliedynamic brake resistance 97 across the.

elevator motor armature 91. The circuitfor resistance 97 maybe traced from'the righthand armature brush, through wire 201, contacts B 183, coil B 135, wire 202, resistance, 97,

a wire 21 3, wire 206, up direction switch holddown coil A 125, contacts A123, to the lefthand'armature brush. The hold-down coils A 1 25 and" B maintain the contacts A 123 andB 1133, respectively, firmly engaged.

Theseparation of contacts A124 and A 126 opens the circuit. for accelerating-switch coil C 156, resulting in the separation of contacts C 153, C154 and C 155. The separation of contacts A122 and-Ar 126 opens the circuit for armature 91. The separation of contacts A 122' and A 128opens the circu1ts .for separately excited field winding 94 and brake release coil 95. Upon the deenergizatic-n. of coil 95, the brake-96 is appliedand, assisted by the dynamic brake resistance 97 connected across the motor armature 91, brings the car to rest at the fourth floor.

Upon deenergizationof coil J 102, retiring cam switch-contacts J separate, resulting inthe deenergization of actuating coil P105 of the potential switch and retiring cam magnet 98. Deenergization of coil P 105 results in the separation of potential switch con- "tacts P' 150, P 151 an'd P 152'which control the circuits for the elevator motor and brake release coil 95, these circuits having previously been opened by the separation of the contacts of the up direction switch A. The deenergization of magnet 98 results inthe operation of the retiring cam to unlock the hatch way door at the fourth floor and the separa 142 and'K 149 to'engage. The separation of tion of the related door lock contacts 100.

*Thexdeener'gization of coil K 141 causes contacts K 143'to'separate and contacts K I contacts K 143,together with the separation of contactsJ 170,.resultsin'the deen'e rgiza'tion of gate magnet 88.- The deenergization of ,magnet 88 resultsin' the 'desce'nt'of valve 43 of the gate closing device '24 to its normal polsition in preparation, for a subsequent gate closing operation. Contacts K -149,'upon encar buttons 104.

through wire for hall buttons'103 and Howeventhe hall 'but tons 103 are ginefiective to control operation of the car, as the circuit for the hall buttons is maintained interrupted in wire 184 by time limit hall switch contacts'V 147. "On en gagement of contacts K 142,'coil T 140 is energized, separating contacts T 146. The separation of contacts T 146 results in the deenergization of'coil V144 of the time limit hall switch; Contacts V 147 of this switch do not reengage immediately the circuit for coil V 144 is broken, their action being delayed by a dash-pot V 145. The dash-pot is arranged to retard theengagement of contacts V 147 but does not interfere'with their separation on energization of coil V 144. The dash-pot is arranged to provide an 111-. terval ofseveral seconds duration between-in terruption ofthe elevator lnotor-circuits'as the elevator-car. nears the fourth floor and the engagement of contacts V 147 to prepare the I circuit through wire 184 for hall buttons 103.

The prospective passenger is thus afforded an opportunity to open the: hatchway door to enter the car without interference with 0011-. of hall trol of the elevator car by operation buttons 103 at other landings.

Let it now be assumed that after thearrival of the elevator car at the-fourth floor in response to the hall button 103, the prospective passenger opens the hatchway 'door to enter the carwith the intention of making a trip to the secondfloor. 'As the hatchway door moves from closed position, the auxiliary door contacts 101' separate. This breaks the circuit for coil'T 140,resulting in a V theengagement of contacts T 146. The en gagement ,or contacts T 146 completes the circuit for coil V 144 of the time limit switch, causinglthe. restoration of contacts V 147 to theirfullyseparated position. The prospec- I tive passenger then opens'the car gateto enter the car. As the car gate 23 is opened, the piston 48islifted opening valve 43, permitting liquid to enter piston cylinder 33; 'As the movement of gate 23 ceases, the valve closes and the liquid entrapped in cylinder 33 supports piston 48 tornaintain'the gate inthe position to which it is moved, .as' previously described.

After'the passenger enters the car, the

hatchway doorat the fourth floor closes and' auxiliary 'door'contacts 101 engage. -The engagement of contacts 101 causes the reenergization of coil T 140, resulting in the separation of contacts'T 146. The separation of contacts T 146 deenergizes coil V 144 and contacts V 147 again start to engage, theirreengagement being retarded as before by dash-v potV 145. Contacts V147 thus'remain'separated for several seconds after the hatchway door closes, maintaining the circuit for hall buttons 10 3interrupted. The passenger is thus 'afiorded an intervalo'f several secassociate onrlsr after the hatchwvayi'door closesandrauX- "operate a: C211-b11ttOIl 104'W1thOut being/subect l tosinterference With Y the control of the carbyope'ration oii-a hall button=103.

iissume' that after the hatch'Wa-y door closes the passenger in thecar operates the carfbutten 10% corresponding to the second :fioor; T h-is results in the energ ization f retiring (18111 switch wild- 102, coil'N 111 of thefloor switch: for thesecond iioor'a'ndact uating 'coil H 160 of the car holding switch. ihiscircuit in'a-y be traced "from Wire 180, through Wire 1-81, safetydevices' 109 'st0p button 108, coil 510:2, Wire 230,coi1N lll 'n'ire-23l second floor carhuttonlOt, W11Q 232, coil-"H160, Wire 185, contacts K 14 9; towvire 186.

W Switch H, llPOTl'jOPGIfiJOII' in response to the energization of its coi1 I-I 160, causes the separation of its contacts 11 163 11111 the" engagementof its contacts H161. l-hepurpose o'f contacts H 161 will-be explained later. The-separationof contacts H 103 againhreaks-the circuit 'for coil T 140, cans ing the 'reengageiment of "contacts T fl lttand the conseqnent reenergization of coil V 114.

energization of coil l T A's aresuit, contacts V 141 are again' restored to their fullyseparate-dposition, Should the permitted time i interval-"expire: a-nd contacts V 147 reengage hefore a car butten is pus-ahed, the-separation of contacts-H163'to'eliect the separation'of contacts=V147,in response to the mshingof a car button,"restores thecar to the exclusive control of the occ-upant of the car, provided a hall button" has not been pushed.

The operation of the second floor-switch N, as aresult of the energization of its coil-h 1 11, 'causes the engagemerit of its contacts N 164. The purpose 1 of these 1 contacts wi ll be explained later. V

The energiZ-ationofcoil {T 102 results'in the engagement of contacts d170, preparing the circuits for actuatingcoil='P 105 otthefp'otcnti'al'switoh and the 'gate magnet 88 com pleting the circuit ofretiring cani ni agnett i. as previously described; @n energization oi magnet 98 the retiring cam [is operated to lockthe hatchway doorat thefou'rth floor and engage lthe :related door lock contacts 100,

The engagement ofcontacts 100, together with the engagement of cont cts'H161; coinpletes 'the circuit for-holdingeoilli 102 of sWitehI-I and'h all breaking switch coil 1157. '1 his circuit may be traced from Wire 180, through wire 1'81, safety devices 109, wire 233, coil H 162, contacts H 161;c(' il'I-15?;W re 178, door loclr-'contafl 100;so Wire'186. The 7 results iii-the sepa ration of'switch contact/S1158 to ti'irther open the hall button circuitji'n wire 1-8-1.

Fhe engagement of door locl-r contacts 100,

1 together With the engageinent of second switch contacts N lfiticoinpletesthe c for non interference switch coil '1: 14-1 and down "direction sivitch actuating 'COll' B "130,

' nares thecircuitfor the field winding 94 this c ii'cuitibein'g also a' holding circnit ffor iliary door contacts 101 engage in Winch to f Second floor switch 'coil' N" :1 11 Z and 'retirin'g cam switch c011 $102. This circuit-may be traced from Wire 180, through wire 18l safety v devicesx1095 stopLbutton 108, coil J- 102,'\vire 230, coil N 111; contacts N164; Wire 28%,Wire 2'36, intermediate switchl117,terminal switch 119" of the floor controller, contacts A 1121' of up direction-switch 11, wire 235, coil B130, wire r177, coil K 141, Wire 1. 8,vdoor lock-contacts l100, to Wire 1'86.

As 'coilf'K' 1411's energized; non interferen'co switch "contacts-K 149 separate to interrupt the; circuit of hall' buttens'103 and car buttons 10 1 i in wire 1'85. Auxiliary centa ts =K i142 also-separate i to "further open the circuit of 0011 T 1 10. *Gontacts K v14$cngage to energi'zethe gatemagnet 98 an'd the gate starts to close, a's pr'eviously described.

be down direction svvltch -B is 1 operated,

hy coil B 130,-simultaneouslywith'the operat1on of non-interference switch K, to effect the-separation of its contactsB'131and*B 183 'and th'e engagement ofitscontacts'BdEiQ, B I

134,'Bi136 and B 1-38. The'separationof conta'cts l3l opens the circuit for actuating-coil A120 of the up direction svvit'ch. "The separation=of contacts 13 183 disconnects dynami brake resistance 97 from across-the armature 91. The engagement of contacts'B 1-3 1 a'n'd paresthe circuit "fora rm'aturetll. The' engagement of contacts B 1'32and P) 138 prehrake release coil i and WVhen'the gate 'reaches' closed position the V gate contacts 106 'engage, "energizing the "actuating coil. P of the "potential s'witc'h andcontacts P 150,? 1 51 andiP 152areen gaged, as previously describedytocomplete the-circuits for arnrature 91, field Winding-94 and b rake vrelease coil 95. The circuit for armature 91'is flQlTlWllB 180, throughcontacts P 151, series .field'winding 93, starting resistance '92, Wire 204, virei205, contacts B 136, wire 201,-ar1nature 91, wire 206, contacts-l i 123, coil 21 12-5, Wire 213, contacts B 132, wire "187, contacts P 150, to wire 18:6.

It will be noted thatthe current flows through" armature 01 in the reverse direction to that in Which it flowed when the up direction switch Wasclosed The circuit for the separately excited field'vvinding 9 1 isjfrom Wire 180, through contacts P 151,'Wire 207, "Wire 208', Winding 94,'c0ntacts B 138, wire 2ll the right half of resistance 97, Wire 21 3, contacts B 132, Wire1875 contacts P l 50 to wire 186. The circuit for brake "releasefjcoil 9E5 dynamic brake resistance 97 connected direction. .10 i gagement of contacts 153,0 154 and C155 in is from wire 180, through contacts P151, wire 207, wire 212,'contact sP 152, coil 95, by of wire 208 to wire 186 as traced for field winding 94. 1

The elevator motor armature and field winding being energized, and brake 96 released as a result of. energization of coil95, the elevatormotor starts the car in the down As the counter E, M. F. of the motor builds up, the coil C 156 causes the ensuccession to short-circuit the starting resistance 92 and series field winding i93 in steps.

' As a result, the elevator motor is brought to gage.

107 separate interrupting the circuit for coil J 102, coil N 111, coil B 130 and coil K "141'.

As coilN 111 deenergizes, the floor switch fcontacts N 164 separate in preparation for a subsequent operation; As coil B 130 deen- 'ergizes, contacts B 132, B134, B 136 and B 138 separate and contacts B. 131 and B 133 engage Engagement of contacts B 131 prepares the circuit of coil A 120 to enable a subsequent trip in the up direction. The

engagement of contacts B 133 connects the dynamic brake resistance 97 across the 'motor armature 91. The circuit for resistance 97 has been traced previously in the description of the operation of the car in the up direction. B 136 opens thecircuit for accelerating switch I 1 coil 0 156, resulting in the separation'of C011.

"tracts-C 153, C 154. and o 155. The separaa I,

' gate closing device 1S IEtlSQCl 1n preparatlon tion of ,contacts'B 132 and B 136'opens the circuit for armatur e91. contacts B 132 and B 138 opens the circuits for the .field winding 94 and brake release coil 95. The deenergizationofcoil 95 results i in the applicationoi brake 96 which,assisted across the motor armature brings the car to rest at the second floor. V

Upon deenergization of retiringcam switch coil J 102, contacts J 170separateto inter-- rupt the circuits of potential-switch coil-P andir etiring cam magnet 98. On deenergization of coil P105, contacts P 150, P151 and P152 separate. 'These contacts control the circuits of motor 90 and brake release coil 95, these circuits having previously been openedonseparationof the contacts of down direction switch B.

to unlock the .hatchway door at the second As the car nears the second floor, the intermediate switch contacts 117 of the controller The separation of contacts B 134 and The separation of i As retiring'cam magnet 98 1s deencrglzed, theretirlng cam operates floor and separate the related door lock contacts 100. I

As coil K141 deenergizes, the contacts K 149 and-K 142 engage while contacts-K 143 separate. Upon engagement of contacts K 149 the car button and hall button" circuits are prepared in wire 185. The hall button circuit remains open iniwire 184 at contacts The separation of. contacts K 143, together with the separation of contacts 'J 170, deenergizes magnet 88 of the-gate closing device. 7 p a i The separationof door lock contacts 100 interrupts the circuit through holding coil H 162 of the car holding'switch H 161 a'nd hall breaking switch coil I157. Coil I 157 on deenergization permits contacts I 158 to engage, preparing thehallbutton circuit in wire 184 The hall button circuit, however,

remains open at contactsV 147. :Coil H.162 on deenergization permits contacts H 161.

to separate and contactsH 163 to engage.

Separation of contacts H 161isinpreparati0n for asubsequent operation under control of a ca-r'button.

H 163, together with the engagement of con- The engagement. of contacts tacts K142, completes the circuit for coil T 140. 'Coil T 140' on'energizationefiiects the separation of. contacts T 146,'resulting in deenergization of coil'V 144. Asv coil V 144 is deenergized, the contacts V 147 start to engage but their engagement. is "retarded V for the interval providedby the dash-pot V 145. The interval provided by dash pot V l45afl'ords'the occupant of the car an op-' portunity to open the hatchway door to leave the car.

fora subsequent gate closing operation.

WVhenfthepccupant .of'the car opens the hatchway door, the auxiliary-door contacts 101 separate, deenergizing coil T 140. As a result, contacts T 146 engage, energizing coil V 144 .to cause the restoration of contacts .V 147 to their fully separated position. 7 The hall button circuit thus remains interrupted This eliminates the-possibility of the carstarting in response to a, hall button roe until the contacts V147 engage under the retarding action of dash-pot 145 after the hatchw'ay door closes and auxiliary door contacts 101 engage. a

In the event that'the occupant ofthe cart desires to change his destination, he may operate the-stop button 103 stopping the car. It is to be noted,"however, that the circuit including hall breakingswitch coil'l 159 is not interrupted thestopoccurs between floors. (lonsequentlyz'the- .hall breaking I switch contacts 'I 158 remain separated'to I prevent control of the car being taken from trol is efiecte d by push buttons.

the occupant by operation of a hall button, regardless of the time which elapses'before another car button is operatedy Although the gate-closing dev ce hasbeen described as adapted" to an automatic push button elevator system, it is equally applicable to other types of controlsystems, such as systems in which the caris provided with an operator to cont'rolboth the startin g and stopping of the car or only the starting trol the energization of magnet 88. In any of these systems, with the gate closing device provided, a person is relieved of the burden of closing'the gate and also a closed car gate is assured while the car is in motion, thus protecting occupants of the earirom the pos sibility of injury in the h'atchwa y.

It is to be noted by contact with projections that inthe embodiment illustrated the ratio ofpistonmovement to closure movement is one to one. Thus, any

error in the operation of the closure operating device can only affect the'movement of the closure 111 an equal, but "not greater amount. Furthermore, this low ratlo facihtates adjustments of the. closure operating mechanism to secure the operation desired. The lengths of the various elements of the closure operating mechanism are determined by the amountof closure movement. It is tobe understood that other-ratios or movement may be provided, if desired. 7 i

The gateelosing device-isadapted to close the gate whether the gate is arranged to be opened by power or manually. While the gate closing device has beendescribed as closing-the car gate, it is also readily adapted to openthe gate.

Although the closure operating mechanism has been illustrated and described as applied to a collapsible car gate, it is equally suited to operate rigid or flexible car gates or hatchs way doors whether they are vertically or horizontally moved. The closure operating mechanismis also adaptedtooperate swinging doors.

operating mechanism facilitates the manual closing operation, as the counterweight moves independently of the'piston, and with-.

The provision of counterweight freely movable in the piston of along stroke closure When the closure operating mechanism is i arranged with the check valve normallyre'sti' ing on the valve seat, a'further advantage resulting is that.the closure is maintained in any positiontowhich it is moved. I

' As many changes could'be madein the above construction and; many apparently widely difl'erent embodiments of this invention could be made without departing from; the scope thereof, it is intended that all mat ter contained in theyabo've description or. shown in the accompanying drawings shall be interpreted as illustrativeand not in alimiting sense. v i What is claimed is: 1 1-. In an elevator system, a closure adapted when open to afford access to the elevator. car,'

means ior' biasing said closure to one ."ofits limit positions, and meansfor controlling saldbiaslng means to prevent its operation to move said closure to .said' limit position, said biasing means comprislng' two relatively;

movable members whose relativemovement is unaffected by said preventing means, one of sa d members bemg connected to said closure whereby the closuremaybe manually moved to said limit position nnaiiected by said'pre- A venting means.

2. .ln anelevator system, a closure adapted when open to afiord access to the elevator car,

means for biasing saidclosure toclosedpofsition, means for controlling saidi biasing":

means to prevent its operationto move said closure to closed position,.said preventing means permitting movement of said closure to open position, and means for rendering s'aidpreventing means ineffective to prevent the operation ofsaid closure to closed'posi- .tion by said biasing means, said ubiasin'g' means comprising. two relatively movable members whose relative movement is unsaf 1 fectedby said preventing means, one of said 7 members, being connected to said iclosure whereby the closuremay. be manually moved to closed position unaiiectedbysaid prevent,

ing means. 7 v 7 8. 'In an elevator system a closure adapted no I when open to afford access'tothe elevator car; and operating means for saidclosure,

said operating means comprising; a. chamber, a

said chamber adapted when closed to prevent escape of saidjfluid'irom said chamber, said fluid, when said' valve is closed, supporting said gravitymeans toprevent itsoperati'on to move said closureto closed positionl .4. In an elevator system; a closure adapted when open to afford access to the. elevator car,

and operating mechanism .for said closure,

said operating mechanism comprising; a

casing, a cylinder in said 'casing, -said cylinder having a I passage at. its lower fend communlcatmg with the mterior-pt.said

: casing,igravity means operable in. said Y tion, a non-compressible liquid in-said cylin-- derand saidcasing, and means adapted to cylinder to'bias said closure to closed posiclose said passage toprevent the flow of said liquid from said cylinder to the interior of said casing, the liquid in'said cylinder sup;

7 porting said biasing means, when said pas} sage isclosed, toprevent its operation to move. the closure to closed position.

5. In an elevator system; a closure adapted when open to afford access to the elevator car andoperating means for said closure,

said operating means comprising,'a'casing having a chamber, fluid within said chamber and that portion of the interior of said casing external to said chamber, a valve for con trolling communication betweensaid chamb erv and sai'dportion of said casing, said valve when open permittingthe flow. of said fluid nbetweenysaid chamber and said portion of .i said casing, and means within saidichambei' having sufiicient weight to move said closure from open to closed position, said fluid when the valve is closed supportingsaid weight Vmeansito prevent'its operation to move said closure means to closed position. a r

6. In an elevator system, a closure adapted i whenopen to aflord access to the elevator car,

and operating mechanism ,for said closure,

, said operating mechanism comprising, a casing, a cylinder in said cas1ng,said-cylinder having a passage at its lower end communicating with the interior of said casing, weight means operable in said cylinder to b'iassaid closure to closed position; a non-compressible liquid in said cylinder and said casing,

a valve for closing said passage to prevent the flow of said liquid from said cylinder to V j the interior of said casing, the liquid in said cylinder,;when said valve is closed, supporting said biasing meanstoprevent its oper- I ation tomove said closure to closed position,

and means for causingthe lifting of said valvert'o permit thGTflOW of liquid from said cylinderintothe interior ofsaid casing therebyiallowing said biasing'means to move said closure'to closed pOSltlOlL'.

a 7, In an elevator system; a closureadapted when open to aflord access to the elevator car and 7 operating means for said closure, said operating means comprising,acasing having a chamber, fluid within said chamber and that portion of the interior o'fsaid casing external itoes'aid chamber, a valve for controlling communication between said chamber and said portion of said casing, said valve when open permittingthe flow oisaid fluid between said chamber and said portionof said" casing,

means within :said chamber having suflicient weight to move'said closure fromopen to closed position, said-fluid when the valve is,

I closed supporting said weight means to preventits operation to move said closure to closed position, and a magnet for causing the liftingof said valve to ennant flow or liquid from said chamber into said portion of said casing thereby'allowingsaidweight to move said-closure means-to closed position;

8. In an elevator system; a closure adapted when open to afiordaccess-to theielevator car; and operating means forsaid closure, said operating means comprising, afca'sing, a cylinder within said casing, 1a counterweight connected to said closure means said counterweight being of insufficient weight to move said closure, a hollow piston within said cylinder and adapted to besupportedby saidl counterweight, said counterweight being Within said pistonand the combined weight ficient to bias said closure means to one'of its limit, positions, a check valvefor control ling communication between said casing and said-cylinder, and liquid within said casing and cylinder, said liquid whensaid valve is closed supporting said'piston, thereby preventing the'movement of saidiclos ure means to said one limitposition by-the combined weight of said piston and counterweight, saidof said piston and counterweight being sufl I counterweightbeing movable within said pig; 7

ton unaflected bysaid liquid. whereby said closure means may bemanually moved to said one. limit position. v 1 v 9. In an elevator'system; a closure adapt ed when open to afford access to theelevator 7 car; and operating means, for said closure 7 comprising, a casing having a chamber and I V a passage communicating therewith, weight means operable within said chamber to bias said closure to one ofits' limit positions, fluid within said chamber, said bia'sing ,;*means, uponoperation to move said closure to; said;

one limit position, displacing said fluid from said chamber through said passage into a portion of said 7 casing externahtoqsaid I chamber, a valve'adapted'to control the flow "of said fluid, and means'adapted on operation tolift said Valve to accelerate the movement of said I closure by said biasing means. i 1

10. In an elevator system; a closure adapted when open to aflord access to the-elevator car; and operating means for said closure comprising, a hollow cylinder, weight means operable within said'cylinder to bias said closure to closed position, fluid withinsaid cylinder, said fluid being adapted inthe'event its escape from saidcylinder is prevented,tosupport said biasing jineansto preventi' opera 'tion thereof to move said[closu refto closed position, valve means for controlling; the flow i said cylinder is not completely prevented,

whereby said biasing means, upon release of said closure after movement thereof 7 from said closed position, iseiiective to return said closure slowly to said closed position.

7 11. In an elevator system; a closure adapt- Vcd when open to aii ord access tosaid car;

I valve means for controlling the flow of said 7 13. In an elevator system; a t ed when open to afford access to the elevator fluid between said casing and said chamber and thus to control the speedwith which" said closure is closed by biasing means, said valve means being opened during movement of said closure from said closed position, and means operable to preventthe return of sa1d valve means to fully closed 'position'so that l'the escape of said fluid from said chamber is not completely prevented, whereby said closure, upon beingreleased after its movement from:

said closed position, is slowly returned'to saidclosed position by said biasing means.-

12. In an elevator system; a closure adapt-l1,

mea-ns effect ve by. permitting sa1d l qu d to flow from said chamber intosaid casing,and

edwhen open to afford access to the elevator car; and operating mechanism for said clo sure comprising, a casinghaving a'chamber, weight means 'operablein said chamber to bias saidclosure to closed position, liquid in said casing and chamber, said liquid being adapted, in the event its escape from sait chamber into said casing is prevented, to support said biasing means to prevent its operation to move said closure to closed position,

and valve means for controlling the flow o'f' said fluid between said casing and said chamber, said valve means being adapted to open during movement of said closure from said closed position and to close whenever said movement of said closure from said closed position stops, thereby preventing escape of liquid from said chamber into said casing so as to maintain said closure in any position to which it is moved. closure adaptcar and o eratin mechanism for said 010- sure comprising, a casing having a chamber,

weight means operable in said chamber to bias sa1d closure to closed position, liquid in said casing and chamber, sa1d liquid being adapted, in the event its escape from said chamber into said casing is prevented, to support said biasing means to prevent its operation to move said closure to closed position, valve means for controlling. the flow OfSftlCl liquid between said casing and said chamber,

said valve means being adapted to open during movement of said closure from said closed position and to close whenever said movement of said closure means from said closed position stops, thereby being effective to prevent theescape of liquid 'from' said chamber into T said-casing so as to maintain said closurein any position to which it is moved, and means operable toadjust said Valve means so that it, cannot return to fully closed position whereby said closure, upon being released ai ter movement from sa1d.

closed position,is returned to said closed-p05 sition'b'y said "biasing means at deter-' mined by the amount which said valve means ismaintained. open, by'said adjustingineans, I 14 In anelevatorsystem,a closure; adapted when open to afford accesstothe elevator sure, said operating inechanismromprising,

car, andppe'rating mechanism 'rorsaidfcld a ca'sing having a chamber communicating tlieinterior of 'said casing, weightnieans ings'aid chamber operable to bias said closure I to closed position, valve means for control-. ling'said communication between said chamher and saidca'sing, a non-compressible 'liq-. uidin'said chamber and said casing, the liduidin said casing'when said valve means is closed supporting saidbiasing meansFto r der saidlbiasing meansineffective to "'move' said closure 'to saidclosedposition, said valve: mea s when openrenderlng sa1d blasing means cooperatingfwith said valve means to car; and operating'means for said closure,

said operating means comprising, 'a casing having a chamber, weight means operable within said chamber to bias said closure to closed position, fluid within said chamber,

and valve means forsaid chamber adapted when closed to prevent escape of fluid from" said chamber, said fluid when said valve is closed supporting said biasing means to ren der said biasing means'ineflective to move sa1d closure to saidclosed position, sa1d clounatfected by said valve means.

sure being operable from said closed position i 16. In an elevator system; agate for said car; and operatlng mechanism for the eleva; tor gate comprising, an elongated casing made up ofa plurality of joined tubular sec} vary the rate at which saidliquid flows ham; said cylinder to"said oasingwlien said valve tions,said'casing being secured to said car, H

a piston guide positioned in o-ne'seotion and resting upon one end of the ad acent section, an. elongated-piston cylinder secured to said piston guide and extending downwardly therefrom, said cylinder being provided with a passage at its lower end communicating Y with the interior of said casing,an elongated hollow piston movable in said piston guide and cylinder, said piston having a looseflt .in said piston cylinder, a non-compressible liquid in'said casing and said cylinder, a"

itu

' sheave supported by the casing at the'upper end thereof, a cable secured at one endfto said gate, said cable passing over. said sheave V V and through openings in the top of said casa ing andthe top ofvsaid piston, a counter- Weight within said pistonand movable with 'respect thereto, said counterweight being I connected to the other end of said cable and being'of insuflicientweight to move said'gate' m to closed position, said counterweightbeing adapted-to support said piston, the combined i A Weight'of said counterweight and said piston being suflicientto bias said ga te to. its closed p0sition, a check valve at theupper end of said passage controlling the flow of said liq l 'uid between said cylinder and said casing, said liquid Whensaid valve is closed support- 1 ing said piston in said cylinder toprevent the movement ofsaid gateto closed positionby' the combinedweight of saidpiston and eoun terweight, a lever for lifting said valve, and a jmagnet supported by said casing, saidimag net having an armature. connected. toisaid r lever, said magnet when energizedkacting f a thro ugh said armature and lever to lift said valve to permit the flow of liquid fromfsaid cylinder into said casing, thereby allowing said gateto be moved to closed position by? I the combined Weight of saidpiston and coun- 3o tervve-ight, the movement. of said counter- Weight, in said piston being unaffected by said liquid, Wherebysaid gate maybe manually closed. V

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

EDWARD LEE DUNN.

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