US2482458A - Elevator - Google Patents

Description

E. M. BOUTON Sept. 20, 1949.

ELEVATOR 15 Sheets-Sheet 1 Filed June 25, 1945 'IIIIIIIIIIIIIA' I If NEY INVENTOR [dyar/Wja u/o/z WITNESSES: 4 1/ E. M. BOUTON Sept. 20, 1949.

ELEVATOR 1s Sheets-Sheet 2 Filed June 25, 1945 INVENTOR f'dy'arflfiaufan.

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Sept. 20, 1949. E. M. BOUTON 2,432,458

ELEVATOR Filed June 25 1945 l5 Sheets-Sheet 3 45 1 INVENTOR L/ ATTORNEY p 1949. E. M. BOUTON 2,482,458

ELEVATOR Filed June 25, 1945 15 Sheets-Sheet 6 INVENTOR fayar/Wflaufon.

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p 1949- E. M. BOUTON 2,482,458

ELEVATOR Filed June 25, 1945 l5 Sheets-Sheet 9 R M VJ? LL/68 we Hg: M.

WITNESSES: INVENTOR 7f)! I [darMBau/an.

TT RNEY Sept. 20, 1949 Filed June 25, 1945 E. M. BOUTON ELEVATOR IIDE/ llfl/VE up; a E; muz

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45-2 L/OD INVENTOR [dyer/1430a for? //%;DRNEY Patented Sept. 20 1949 'EL vA'ron Edgar M. Bouton, Nutley, N. J., assignor to West-' inghouse Electric Corporation, East Pittsburgh,

. Pa., a corporation of Pennsylvania Application June 25, 1945, Serial No. 601,388

- 47 Claims. I 1

My invention relates to elevators and more particularly to high'speed elevator systems designed for serving a plurality of floors intall buildings.

In elevator systems of this character, it is customary to provide signal systems for indicating the position of the cars with reference to the floors and forindicating to intending passengers at the floors which car'will stop for them, to provide control systems by which the cars may be started and stopped by switches or push buttons in the cars and in the floor landingsand to provide a floor selector for-each car which will operate in response to 'movement of the car past the floors it serves for correctly connecting the signal and control circuits for such floors as the car approaches theml One object of my invention is to provide an elevator with a control system, a signal system, and a floor selector therefor which shall be simple and inexpensive to construct, install and maintain in operation andwhich shall be more accurate in operation than those heretofore'provided. 1 1

Another object is to provide an elevator system in which the floor selectors will not only connect the various signal and control circuits for the floors as the cars move from floor to floor, but will also automatically take care of the acceleration, running, deceleration'and stopping of the cars in response to operation of the starting switches in the cars and thestop push'buttons in the cars and at the floor landings.

Another object is to provide an improved control system for securing the most efiicient operation of the hoisting motor without the necessity of personal attention by the car attendant.

Another object is to providea signal and control system which will require relatively few electrical relays, and in which light pile-up contacts of the telephone type may be used instead'oi heavy contacts. p A further object is to provide a-system in'which most of the control and signal; apparatus, together with the necessary wiring therefor, may be assembled with the floor selectors at the factory and be madeready for installation instead of having to assemble such apparatus individually in the penthouse or in the elevator hatchway at the time the elevator installations are made A further obiectiistoprovide a control and signal system for an. elevator making an express run to an upper local zone in which the floor selector may be designed for only'the upper zone without including parts which would otherwise be necessary for the floors included in the express'zone as the car moves through that Zone to the upper local zone;

A further object is to provide means for checkingthe position of the decelerating controller every time thecar stopssoas to ensure an accurate position of; the controller for the initiation of the decelerating action at the next stop.

Another object is ,to provide an elevator system in which the speed oi'the canasit slows down for a stop'at a floor, is tied intimately to the position of the car asit slows down for that floor.

Another object is to provide an elevator system in which the means. forcontrolling the speed of the car 'is operated directly by the floor. selector.1p

Another object is to provide anelevator system in which the initiation of the .slowdown of a carior a stop at a floor is made at a predetermined point as the car approaches that floor and in which the relationof the stationary and the moving parts of the floor-selector determines such predetermined point. v

Another object/isrtoprovide' an elevator system in which the speed of the car during deceleration for a stop will be brought down to a predetermined value at approximately a given distance from the floor each time such'operation takes place.

Another object is to provide an elevator system inwhich the'slowdown of a car for a stop will be initiated at a point a predetermined distance from the floor at whichthe stop is to be made, and the initiation of the final slowdown operations of the selector w illbe made at a fixed distance 'closeto the floor."

Another object is to provide a control means operated by a floor selector for decelerating a car to a stop at a floor and causing the control means I to decelerate the carin coarse steps during the early part of the slowdown-operation and 'for causing "the control means to decelerate the car in fine steps during the finalpart of the slowdown operation as the car nears the floor. I

Another object is to provide a leveling system which will respond to one condition and operate in one manner when the car is being leveled to a floor during the stopping operation and which will respond to another condition in another manner for releveling the car if it leaves the floor while stopped thereat because of cable stretch or other conditions.

Another object is to provide an elevator control system in which a floor selector operated in accordance with the movements of the car is provided with means for actuating a control for the car motor which will be set into operation by a stop signal when thecar approaches to within a predetermined distance of that stop signal and will be thereby operated to decrease the speed of the car in predetermined steps from its high speed to a relatively low speed by the time the car reaches a fixed distance from the floor, for initiating a final deceleration as the car reaches said fixed position which will be made in finer steps so that the car will softly and easily reach a very low stopping speed as it arrives closely adjacent to the floor level, and for then cutting off the power and applying the brake while the car is moving at such low stopping speed so that it will stop approximately level with the floor for which the stopping operation was initiated.

It is also an object to provide an elevator system in which the floor selector for the car .and

the means associated therewith for accelerating,

running, decelerating, and stopping of the car may be operated by and in accordance with the movement of the car without any physical connection to the car.

Further objects of the invention will be obvious in the following description when taken in conjunction with the accompanying drawings, in which:

Figure 1 is an illustration of an elevator system embodying my invention;

Fig. 2 is an illustration in side elevation of the hoisting drum and the upper portion of the roping for the elevator shown in Fig. .1;

Fig. 3 is an illustration of the relation to each other of the various mechanical features of the floor selector mechanism embodied in my improved elevator system;

Fig. 4 is an enlarged view in front elevation of the floor selector mechanism embodied in Fig. 1;

Fig. 5 is a view in side elevation of the floor selector mechanism shown in Fig. 4;

Fig. 6 is a top plan view of the floor selector mechanism shown in Fig. 5;

Fig. '7 is an enlarged viewof the blocks of contacts on the floor selector and the carriages for operating them as taken along the line VII-VII of Fig. 5;

Fig. 8 is an enlarged view in front elevation of the up contact operating carriage embodied in the floor selector illustrated in Fig. 4;

Fig. 9 is a view in side elevation of the carriage illustrated in Fig. 8;

Fig. 10 is a view in side elevation of one of the contact-operating devices mounted on the down floor selector carriage;

Fig. 11 is an enlarged view in rear elevation of the motor controller and the leveling controller;

Fig. 12 is a bottom plan view of the limiting lug and fingers on the lower end of one of the controllers in Fig. 11;

Fig. 13 is an enlarged view in rear elevation of the differential devices for operating the floor selector and the motor controller and the leveling controller;

Fig. 14 is a reduced top plan view of the brakes 4 and brake lever taken along the line XIV-EV in Fig. 13

Fig. 15 is a view in side elevation of the diiferential device Kl shown in Fig. 13;

Fig. 16 is an enlarged sectional view of the clutch lever in Fig. 15;

Fig. 17 is an enlarged top plan view of the clutch lever in Fig. 15;

Fig. 18 is a view in side elevation of the differential K2 shown in Fig. 12;

Figs. 19 and 20 are diagrammatic representations of the opening and closing of the contacts on the controllers shown in Fig. 11;

Figs. 21 and 22 collectively constitute a straight-line diagram of the control system for operating the system illustrated in Fig. 1;

Figs. 21A and 22A are key sheets showing the relay coils and their contact members disposed in horizontal alinement with their positions in the straight line circuits in Figs. 21 and 22 so that their locations and connections therein may be readily determined;

Fig. 23 is a wiring diagram of the control relays to be added to the system when it is to be used in connection with a car expressed to an upper zone;

Fig. 23A is a key figure for Fig. 23;

Fig. 24 is a straight line diagram of the circuits for the hall buttons in the upper zone above the express zone.

Fig. 25 is a view in front elevation of the up and the down carriage stop lugs and contacts, including false floor stop lugs and contacts, to be used on the floor selector when the system is adapted to operate a car as an express car to an upper zone; and

Fig. 26 is a top plan'view of the centering plate used on the motor controller in Fig. 11 when the selector mechanism is adapted to express operation of the car.

Lrsr or RELAYS, E'rc.

Individual to each car l-emergency stop and pre-energization relay.

U--up direction switch.

D-down direction switch.

Ii-car running relay.

32Tcontrol conditioning relay.

43T-1Ve1ing relaylfor controlling leveling for cable stretch.

UEauxi1iary up stoppingrelay.

DE-auxiliary down stopping relay.

H-clutch magnet control relay.

Bil-car starting relay.

22auxiliary door relay(starts doors opening).

45-door closing relay.

40open-door safety relay.

W-up direction preference relay.

X-down direction preference relay.

-auxiliary leveling relay.

'IM -transfer brake magnet.

CM-clutch magnet.

GR4speed relay.

GR6--speed relay.

GR8speed relay.

GR6Ttime accelerating relay.

GR8T-time accelerating relay.

UF-up leveling inductor.

DF-down leveling inductor.

T-torque reducer for advance motor (AM).

438--hall button stopping relay.

38R-no car call above relay.

DNPpawl magnet coil on down selector carriage.

UPP- pawl'magnet coil on up selector carriage;

l8-high call reversal relay. I AM-advance motor. CC-car button retaining coils.

. Express zone relays 'ER -express relay. EI'1express inductor relay.v

:ERX-express time ,delay relay.

"Common to all cars IGDR sQDRf BDRV Down hall call registering relays.

'IDR

ZDR

Up hall call registering relays.

serving eleven floors in a building, in which the l floors are approximately ten fee apart. It is to be understood, however, that the invention may be applied to a car or a plurality of cars operat-' ing at any desired speed for serving any desired numberof floors having various height ceilings, but it is believed that the system will be particularly useful for high speedcars serving a large number of floors or for express cars serving special groups of floors in the upper stories of tall buildings.

It should be understood further that all measurements, distances, etc.,' given in this descrip+ tion are given as examples of what may be used satisfactorily and are not to be taken as limita tions intanysense, it being obvious that each installation will have to be designed to meet the conditions peculiar to that installation and that it will be necessary for the application engineer to modify thesystem where necessary to meet the conditions under which it is to be used.

Any desired number of cars may be added to the system described herein by adding control and signal circuits similar to the circuits for car A for each car, and connecting their hall call cancellation contacts to the cancellation coils, such as 2UN of the hall call registering relays (Fig. 22) as indicated by contacts such asBZUZ.

The car is suspended on a hoisting cable 10 which passes over a hoisting drum I l and around a traction sheave l2 to a counterweight l3. An electric motor I4 is provided for operating the hoisting drum H to raise and lower the car and a brake I5 is mounted on the frame of the motor for stopping the car after it is decelerated to topping speed and for preventing its further movement in making a stop at a floor landing. A door 3| vis disposed at each landing to permit entrance to the car. i I r A push button switch CS is mounted in the oarfor starting the car. H l l p A plurality of suitable stop control, devices such aspush buttons 2 and 3, one for each floor, are ,mounted'inthe car by which the attendant may, causecthe car ,to stop automatically, at any floor at which a passenger desires to get off.

An' -up s'top' control device and a down stop control device, such as push buttons 'zUB-and ZDB, are mounted .atleach intermediate floor, with a single push button at eachterminal, so that waiting passengers at the floor landings may press such buttons to cause the car to stop automatically for them; In starting the car, the attendant clos'es the car switchCS until the car startsto move and thenopens it to place the car junder control of the stopping buttons so that it will stop automatically at the floors in fresponse to operated car-buttons or operated hall-buttons.

Th'e'car is provided'with direction preference relays (to be described later herein) which cause it to continue in the direction in which it'starts until it a'rrivesat the terminal" toward which it is -moving where it is automatically reversed to travel tothe opposite terminal. Hence, all the attendant has to do in operating the car is to press the car stop buttons asthe passengers call their floors and press the starting button to restart the car after each'stop iscompleted. j

' At times, it maybe desirable for the attendant to'reverse the car when it stops at some floor between terminals and an up direction push button UPB and a down push button DPB are mounted in the car for this purpose. e An up stopping and-leveling inductor relay UP and a down-directionstopping and leveling inductor relay DF are disposed on a bracket 16 mounted entire car in position to cooperate with an inductorplate IP. The'inductor plateis con structed' of magneticmaterial and is mounted on thewall of the hatchway 9 in position-to cooperate with and actuate contact members on the inductor relays when'the relays are in an energized condition as the car approaches the floor at which it is to stop, I have shown an inductor plate for 'onlyfon'e' floor, but a similar inductor plate should be provided for each floor. v

The inductor relay UP is provided with normally open contacts UFI and the relay DF with normally open contacts DFI. The relays'should be mounted on the bracket [6 with the contacts UF! approximately 20% inchesdistantfrom the contacts DFl. The inductor plate I? should be approximately 19% inches long and should be so located on the hatchway wall adjacent the landingfioor for which it is intended that it will be centered between the contacts UFi and DFI when the floor of the car is level with'the landing floor. 1

An up signal device and a down signal device, such as a floor lantern 2LMU and a floor lantern ZLMD, are mounted at each floor landing to indihate to waitinggpassengers thereat when the car will stop 'for'them and the direction inwhich it is traveling. Ajiloor selector mechanism I8 is associated with the car for connecting the various control and signal circuits of -the car in accordance with its movement relative to the floors it serves and its direction of operation. Any suitable selector power meansfresponsive to operation of the car may be used for operating the floor selector mechanism by the car in accordance with the movement of the car. 1 As one example of such a suitable selector power, means, I have illustrated .a selfrsynchronizing drive embodying a motor SM operated by a synchronous; generator SG which; is connected to the shaft 19 of the traction sheave l2 by apinion 20 and a gear whefil 2i. For a more, detailed description of the drivereferencemay be had to J. F. Peters Patent DESCRIPTION or FIG. 3

As illustrated in Fig. 3, the floor selector mechanism 18 includes the synchronous motor .SM, .a floor selector FS, a controller means such as a main controller M, and a leveling controller L an advance motor AM, a first difierential Kl operable by the synchronous motor and the advance motor for operating the floor selector, and a second differential K2 operable by the synchronous motor and the advance motor for operating the controllers.

The floor selector for connecting the various control and signal circuits of the car includes .a

lurality of sets of pile-up contacts such as 9U and SD of the telephone type, for connecting the signal and control circuits for the various floors, an up carriage UC and a down carriage DC for operating the groups ofcontacts, and a chain drive 23 operated by the synchronous motor SM through the medium of a first differential Kl for moving the carriages up and down to operate the sets of pile-up contacts as the car moves from floor to floor. A safety slip clutch 24 is disposed between the synchronous motor SM and the difierential Kl to prevent injury to the apparatus if the gears bind or the motor starts to burn up too much current.

The main controller M is provided for setting up time-controlled accelerating steps for the hoisting motor when it starts and, when the car is to be stopped, for decelerating the car in coarse steps from its normal high speed of, say, 800 feet per minute down to an intermediate speed of, say, 100 feet per minute.

The controller L is provided for continuing the deceleration of the hoisting motor in fine steps from the intermediate speed of say 100 feet per minute down to a low landing speed of say feet per minute. In other words, the controller L acts as a vernier to reduce the speed of the hoisting motor, during the last stage of its deceleration, in such minute degrees as to enable the car to be brought softly and easily to a very low landing speed so that it will stop level with the floor when the hoisting motor is deenergized and the brake is applied. The leveling controller L is also used for controlling the hoisting motor in releveling operations.

A brake mechanism 25 and a clutch 26 are provided for sequentially rendering the controllers M and L operable through the differential K2. The brake mecchanism includes a brake 21 for a first driven shaft or member 28 by which the differential K2 operates the controller L, a brake 29 for a second driven shaft or member 30 by which the differential K2 operates the controller M, and electromagnet TM for applying the brake 21 to the shaft 28 and a spring 32 for applying the brake 29 when the magnet TM is deenergized.

An electromagnet CM is provided for disengaging the clutch 26 and a compression spring 33 is provided for engaging the clutch when the clutch magnet is deenergized.

A pin 34 is attached to the operating arm of the clutch 26 for centering the controller M to its correct position each time it is returned to its oil position.

The shaft of the advance motor AM is connected to the differential Kl for operating it to advance the floor selector carriages ahead of the car and to the differential K2 for operating it to 8 rotate the controllers M and L to their full on positions each time the car is started.

The shaft of the synchronous motor SM is connected to the differential KI and is used for keeping the fioor selector carriages moving after the car gets up to normal speed for rotating the controllers L and M from their on" to their off" positions when the car is to be decelerated to a stop. The acceleration of the car is controlled by time delay relays and its deceleration by the controllers.

DESCRIPTION OF FIGS. 4 To 10 INCLUSIVE As shown in the detailed drawings designated as Figs. 4 to 10, inclusive, the floor selector mechanism is provided with a main frame 35 comprising a plurality of vertical angle irons 36, 31, 38 and 39, a plurality of horizontal top angle irons 4|, 42, 43 and 43a, and base angle irons 44, 45, 46 and 41. These angle irons are welded together at their joints to form a' strong rectangular frame for supporting the floor selector FS, the motor controller M, the leveling controller L, the differential devices KI and K2 and the motors SM and AM.

The floor selector FS has an auxiliary frame 49 constructed witha top plate 50 and a bottom plate 51 connected and spaced apart by a Pinrality of carriage guiding vertical rods 52, 53, and 54, a pair of contactsupporting rods 55 and 55, and a pair of stop lug rods 51 and 58. The ends of the rods pass through the plates and are positioned and held firmly therein by a. plurality of nuts 59.

The auxiliary frame 49 is mounted on the main frame by means of a topside hinge and a bottomside hinge 6i. The pivot end of the hinge 6B is rotatably mounted on the main frame by a hinge pin 62 disposed in a bracket 63 attached to an angle iron support 5 3 mounted on the vertical angle iron 37 of the main frame. The shank end of the hinge 68 is threaded on the vertical rod 56 and provided with an arm 66 which is firmly fastened to the top plate 50 by a pair of bolts a. A nut 59a is disposed on the rod 56 to hold the shank end of the hinge firmly against the top plate 5|. The bottom hinge BI is constructed and mounted adjacent to the bottom plate 5| in the same manner. The hinge mounting of the auxiliary frame permits it to be swung outwardly so that the carriages, pile-up contacts and chain drive may be easily mounted in position, inspected and maintained in good working condition.

A bracket 8'! is seated on the rear central position of the top plate 59 and firmly held in that position by the nuts 59 on the upper ends of the rods 53 and 55. A pair of positioning bolts 68 and 89 are mounted on the upper portion of the bracket in position to impinge against the angle iron 43a in the main frame when the auxiliary frame is in its closed position. The bolts 68 and 59 may be rotated to adjust the position of the auxiliary frame against the main frame. A pair of holding bolts 10 and ll are disposed beside the positioning bolts in the bracket so that they may be screwed into the angle iron at to hold the auxiliary frame in the position to which it is adjusted by the bolts 63 and 59. A similar bracket 12, with adjusting bolts and holding bolts, is mounted on the underside of the bottom plate 5| to engage the cross angle iron 44 when the auxiliary frame is in its closed position. When it is desired to have readyaccess to the apparatus on both sides of-the auxiliary frame, the holding bolts are screwed out of the angle irons and the frame is swung outwardly so that both sides may be readily examined.

Four blocks'of pile-up contacts for each floor are mounted on the floor selector for connecting the signal and control circuits therefor. These blocks of contacts are given the reference characters P, U, S and D with anumeral prefix to indicate the floor with which they are associated. The individual pairs of contacts in each block are given the reference character for that blockwith a sufiix number to distinguish it from the other contacts on that block. As an example, the P block for the 11th floor is marked HP, and the pairs of contacts on it are marked HPl, etc.

In looking at Fig. '7, we see the P and U blocks of contacts for the 11th floor and the S and D blocks of contacts for the 1st floor.

The group of pile-up P contacts for the 11th floor is designated as HP and is mounted on the inner end of a strap-iron bracket 13, which is welded or otherwise secured to a U-shaped supporting bracket 14 disposed to embrace the contact carrying rod 55. A tapered bolt 15 is inserted through the ends of the bracket 14 to impinge against the rod and hold the bracket in any position on the rod to which it may be adjusted. The block of pile-up contacts HP includes a pair of contacts HPI and-a pair of contacts MP2. The contacts are mounted on contact arms 16 and operating arms 11 disposed in a holding block 11a attached to the rear end of the strap support I3. The contact ends of the operating arms 1'! are provided with operating blocks 19 disposed to be actuated by a main operating arm 88 on which is an operating button 8|. The base end of the main operating arm 88 is attached to the supporting block 11a. When the button 8! is pressed outwardly, it causes the contacts HP! to close. A stop arm 82 is attached to the block 11a to limit the return motion of the main operating arm 88. The block of P contacts is disposed to be operated by the up carriage U0 and its contacts, IIPI are connected for operating indicator lamps (not shown); for indicating the position of the car in its hatchway, as'shown for instance in Patent No. 2.085.135, issued June 29, 1937, on im provement in Position indicators by H. W. Williams.

The block of up pile-up contact devices I IU for the 11th floor is mounted on the outer end of the strap 73 and includes contacts such as HUI, etc. This group of pile-up contacts is constructed in the same manner as the group P and is operable by a button 83 onan arm which moves outwardly on the up carriage when it is stopped as described later. The contacts on the U blocks of contacts for the various floors are used for lighting the up floor lanterns and for cancelling up stop calls at the floors when the car stops thereat.

The groups of pile-up contact members S are provided with individual pairs of contacts such as 153, etc, and are constructed in the same manner as the group of pile-up contacts I IP, but are mounted on the inner endof a strap-iron support 84. The strap support 84 is welded or otherwise secured to a U-shaped bracket 85 held by a tapered bolt 86 on the contact supporting rod 56. The pile-up contacts S are provided with anoperating button 81, which, when operated, will open some of the contacts and close others. I

The S contacts are operated by the down carriage DC and are used for connecting and open ing circuits for the stopping relays to pick up stop calls and for the "call above relay to determine when the car should reverse. For instance for the 11th floor.

the contacts such as 2S4xare closed each time the car approaches the 2nd floor and, if the car is moving upwardlyv and a stop call has been registered on the up hall button 2UB', the closing of the contacts 284 will pickup the call registered on relay ZUR and thereby cause the car to slow down and make an up stopat'the 2nd floor.

The group of down pile-up contact devices ID, which includes a pair of' contacts IDI and a pair of contacts ID2, is constructed in the same manner as the group IIP of pile-up contacts and is mounted on the outer end'-ofthe strap support 84 and provided with-a button 89 which, when operated, will close both pairs of contacts. The contacts on the block ID are operated by the down carriage DC' andare used for lighting the down floor lanterns andfor cancelling the down stop calls. I Y

The contacts for any floor are spaced from the contacts for the next adjacent floors in accordance with the distance between the floors so that their position on the selector is a miniature reproduction of the distances between the floors served by the elevator. For'instance, with a scale of one-eighth inch equals one foot for the spacing and the distance between the 10th floor and 11th floor is nine feet, the sets of pile-up contacts for the 10th floor will be disposed a distance of one and one-eighth inch from the pile-up contacts The stop lug rod 51 carries a plurality of up stop lugs (Figs. 5 and 7), one for each floor. The up lugs are designated as IUN for the 1st floor, ZUN for the 2nd floor, etc." The up lug lUN embodies a projecting member 89 and may be securely fastened to the rod 5l-by a pair of bolts 98 and a crossbar 9|. The lug is placed on one side of the rod andthe crossbar 9! on the other side so that by screwing thebolts through the bar and into the lug, the-lug may be firmly seated at any desired point on the rod, The up lugs are used to stop the up carriage'when the car, in moving upwardly, approaches a floor at which an up stop call is registered. Thelug rod 58' is provided with a similar set oflugs forthe down direction which are designated as IDN, etc.

The stop lugs such as IUN- are spaced apart on the lug rods distances proportional to the distances between the floors, in the same manner as the sets of blocks ofpile-up contacts are spaced apart and at points where they w'ill stop the carriages in such positions that they will operate the contacts for the corresponding floors.

The up-carriage UC (Figs. 8 and 9) has a strap frame 95, bent somewhat in the form of the letter G. Two pairs of rollers wheels 95, 91, 98 and 99 are mounted on the top of the carriageframe by means of a wheel bracket I00 and a bolt [E35, A similar set of wheels I02. I03, etc., is mounted on the underside of the'lower end of the carriage frame by a wheel bracket I06 and a bolt I01.

The wheels 96- and 91 on the upper end of the carriage and the wheels I02 and I03 on the lower end of the carriage are disposed to impinge against or embrace the vertical carriage guiding rod 52 and the wheels 98,89, etc., on the Opposite side of the carriage are disposed to engage the rod 53, so that the carriage may slide up and down between the rods 52 and 53-- with practically no friction.

A pawl arm I Ill is pivoted on the carriage frame by apin Ill disposed in a bracket H2 and a brace arm H3. The arm H3 is seated on the upper surface of the lower end of the carriage frame to which it maybe welded or otherwise se---

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