US1360420A - Electric elevator - Google Patents

Description

N. 0; LINDSTROM AND C. F. E. OLOFSON.

ELECTRIC ELEVATOR.

APPLICATION HLzD1uLY15.19|8.

Patented Nov. 30, 1920.

l ATTORNEYS. v

CML-'26. Y i l WITNESS:

. an exact .level with the floor.

UNITED STATES PATENT OFFICE.

NrLs O. LINDSTROM, or NUTLEY,`AND CARL E. E. OLOFsON, Or HILTON, NEW JERSEY, ASSIGNORS To ALONSO E. SEE, or BROOKLYN, NEW YORK.

ELECTRIC ELEVATOR.

Specification of Letters Patent.

Application led'July 15, 1918. Serial No. 244,859.

To all whom it may concern:

Be it known that we, NiLs O. LINDsrRoM and CARL F. E. OLoFsoN, citizens of the United States, residing at Nutley and Hilton, respectively, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Electric Elevators, of which the followingr is a full, clear, and exact description.

This invention relates to electrically driven and controlled elevators and has special reference to that type of machine which is adapted to be controlled by an operatorwho manipulates a lever or other equivalent device in the car to start and stop the car at will, and is convertible to be operated by what is known as automatic push button control in which the car automatically moves from one floor to another selected floor, in responseto the operation of a push button located upon any fioor, or a selected push button located within the car itself.

rIhe primary object of our invention is to equip such a system with means whereby when the car is under the control of an operator he will be able to bring the car to an exact level with the floor whenever desired, and likewise when the car is operated through the automatic push `button control, it will of itself always finally come to'an exact level with the floor at each stop. The necessity for making exact landings is more important in connection with freight ele-j vators than with passenger elevators, since in freight elevators it is desirable to facili` tate the loading and unloading of the car and in the movement of trucks or heavy packages from the landing to the car of the platform, it is important, as can be easily understood, that the platform shall be on The motor used for freight elevators is ordinarily a single speed machine which` although slow running compared to that of passenger elevator motors, isnevertheless of too high speed to permit of bringing the car to an accurate landing at once, except by chance. Furthermore, the load on the car and its direction of movement are factors which affect the accuracy of making landings. If the car stops above or below the landing, it is difficult to control the motor on account of its high normal speed to bring the car to the exact level desired, and it often occurs that the attempt to make the landing has to repeated several times.

The present invention comprehends, among other things, the use of a change speed mechanism which will afford so great a reduction in speed between the motor and Patented Nov. 30, 1920.

the winding machinery that the car after stopping within proximity to a desired landing may beI moved slowly and therefore with accuracy to an exact level with the floor. `While it is not new to introduce change speed devices between a source of power and the work in various classes of machinery, to do this in connection with an electric elevator necessitates the provision of certain automatic controlling devices to prevent strain upon the machinery and to cause the apparatus to operate smoothly and accurately as intended. When the system, such as above referred to, is under manual control the change speeddevice included' in our invention is manually thrown into use and the car thereafter manually brought to a stop'at the desired level, but when the car operates under the vautomatic push button control, the mere fact that it cornes toa stop at s ome pointrabovev or below the floor, results in the introduction of the speed change device and thereafter the slow movement of the car to an exact level with the fioor and the stoppage of the car at that level; Our invention therefore comprehends broadly the combination system referred to adapted to be converted for operation on either plan atwill and affording the same degree of accuracy in making landings under both conditions.

In the accompanying drawing:

The figure isa conventional diagram of Aapparatus and circuits required to illustrate the principles of the invention, certain fea-l Atures necessary for a complete elevator in- VVstallation".being omitted for the sake of ff'clearness.

The Winding drum or machinery which moves the elevator car, is indicated by l and is driven by shaft 2 which in -turn is driven by the shaft 3 to which the driving motor is connected. The two shafts 2 and 3 are lined .up 4and 'have interposedbetween them a speed'changing device of any suitable character, the type of which is immaterlal to the present invention. The drawing, however,

shows conventionally a .Gear such as we may 2 will be driven at the same speed as the power shaft 3, and also when the drum is moyed to the left by the pressure of the brake shoe 5 and is held stationary between said brake shoe and the friction surface 6, an internal set o'f gears within the drum will be interposed between the drive shaft 3 and the driven shaft 2 so that the latter will rotate at a very much lower speed than the former, say, at a ratio of 1 to 10. The brake shoe 5 and drum 4 are moved` by the lever 7, pivoted at 8, and carrying an armature 9 which is subjected to the attraction of a solenoidal coil 10, but which is normally held retracted by spring 11. The leve'r 7 may be regarded as the controlling element of the speed changing device, which element is to be operated by the electric circuits and the devices to be hereinafter described for the purpose named. The lever 7 in its normal position, as shown, holds a cut-out lever 12 in open circuit position. When the lever is moved to the left, a spring acting upon the cut-out lever causes the latter to connect with the contact point 13.

The circuit diagram is adapted for threephase alternating current distribution, but the invention may likewise be carried out with two-phase or direct current, as may be desired. The driving motor which actuates the shaft 3 is indicated at M. The main switch controlling the three main lines 14, 15 and 16 is indicated by S. The controller on the car by which the car is manually started and stopped at will, is indicated at C and comprises a hand-operated lever c movable into the four branches of an H-slot in the plate c. The circuit controlling end of lever c is provided with a conducting blade c2, which is adapted to connect together two contacts arranged on each side thereof and indicated on one side by 17 and 18, those on the other side not being specifically designated, since it is unnecessary to refer to them hereinafter. It is suiicient to say that the two contacts on one side are intended for a movement of the car upward while the two on the other side are intended for a movement downward. By throwing the lever to the left through either of the long slots, theA contacts 17 and 18 are connected together. lVe will assume that the upper slot in plate c is used for the normal high speed running of th'e car from floor to oor, while the lower slot is used when the speed changing device is to be thrown in by the operator to effect an accurate landing at a floor. The lever carries a conducting bar 19 which, when the lever is in the upper or high speed slot,forms a connection between two contacts 20 and 21; when the lever passes from the high` speed slot through the cross passage to the low speed slot, the connecting bar 19 opens the circuit between the contacts20 and 21 and holds vthis circuitopen as long as the lever operates in the low speed slot.

The diagram includes conventionally a circuit breaker, and 11p-switch, and a down switch,77 these devices being indicated by their names upon the drawing, and their equivalents being ordinarily included in allV electrically controlled elevator systeins. Besides these switching devices, the system also includes a high speed switch, a low speed switch and a time switch, also indicated on the drawing by their names. The circuit breaker, up-switch, down-switch and low speed switch are double pole devices, the arms of which are mechanically connected by non-conducting bars c. It will be assumed that either gravity or a spring acts upon all of these switches in opposition to their respective magnets, although the springs are not shown. The low speed switch comprises two independent coils, the purpose of which will be explained in the operation. The time switch comprises a conduct-ing lever 22 pivoted at 23 and adapted to have a considerable upward stroke under the influence of a solenoid 24, the core of which is attached to the lever. This lever normally rests in its lower position and in connection with a contact 25. In rising under the influence of the solenoid, the lever lirst breaks connection with contact 25 and then makes connection with a movable contact 26 which is pivoted so that it will ride upward to the limit of movement with the lever, maintaining its contact 100 therewith until the return of the lever to its lowest point where the connection is broken with contact 26 and renewed with contact In these excursions of the lever 22, it is under the control of a dash-pot 27 which, as 105 usual, is subject to adjustment so that the time required in the movement may be controlled to suit the conditions. One of the levers of the circuit breaker carries a conducting bridge 28 which, when the circuit 110 breaker is closed, connects contacts 29 and 30. Likewise one of the levers of the upswitch carries a bridge 31, which, when the switch is closed, is adapted to connect together the three contacts 32, 33 and 34; and 115 one of the levers of the down-switch carries a bridge 35, which, when the switch is closed, is adapted to connect the three contacts 36, 37 and 38. The high-speed switch lever, when open, connects-with a contact 39.

At F is shown a double pole switch having either of two posit-ions, in one of which (that shown in the drawing), the system is adapted for manual control by an operator n indicated by the dotted line g engaged by a inion on the shaft g2 of the winding drum.

n the face of this disk is a cam groove g3 comprising two semi-circular concentric portions of different radius connected together by an inclined portion g* to form a continuous cam track. Adjacent to the face of this disk are stationarily mounted anumber of bell crank switch levers corresponding to the number of floors through which the shaft of the elevator runs, there being three shown in this particular instance and they being designated by I, H and III. These levers are assumed to be pivoted upon a suitable frame, concentrically around 'the shaft y), one arm of each being a# switch lever, while the other arm carries a roller or pin engaging withthe cam groove in the face of the disk. The rotation ofthe disk through its connection with the drum shaft and the spacing ofv the levers around the center of rotation, is such that when a bell i crank is traversing the inclined portion g* of the cam slot, the car is at the same time passing the floor corresponding to the particular bell crank switch. The switch arms of the two terminal bell cranks are adapted to make and break connection each'with two contacts as shown, as the rollers on their opposite ends move from one circular portion of the cam slot to another. The terminal bell cranks correspond to the bottom and top floors of the building respectively, and the closing of the contacts by one of these levers determines that the movement of the car will be either downward or upward` depending upon which lever is actuated. The intermediate bell cranks corresponding to the intermediate floors, and of which only one is shown in the drawing, have a pair of contacts on each side, one pair being closed when the bell crank is swung in one direction for an upward movement of the car, and the other pair being closed by a movement of the bell crank in theopposite direction for a downward movement of the car. This mechanism is known as a floor regulator or foor selector and its equivalent is used in all push button control systems; hence its construction in detail is not further illust-rated or described. There is represented at the left of the diagram 3 floors of the building, each of which is provided with a push button and a door switch; also inside of `the car are shown three push buttons 79, p', p2 corresponding to the three floors of the building which may be actuated by any passenger who steps into the car to be carried to a particular Hoor, the same thing being accomplished by these buttons as by the buttons on the various floors, with which they are in parallel relation in the circuits. There is also a stop button p3 in the car to be mani ulated as usual in case of an emergency. he car is also equipped with the usual door switch p4. At the upper and lower ends of the shaft are the usual limit switches g and r, respectively. s, s and s2 are the usual floor magnets which are energized by the closure of the push buttons on the various floors, orin the car, and which thereafter maintain certain circuits closed during the movement of the car, as will be more fully explained. s3 is a noninterference magnet commonly used to prevent interference with the movements of the car after it has once been started toward a given floor. s4 is a master magnet,.introduced by my invention, and operating as willhereinafter be explained in connection with the push button control for determining whether the car shall be moved at high or low speed.

Arranged along the elevator shaft at each floor is a cam, indicated by t. Each of these cams is provided at its upper and lower ends with inclined faces t and with a straight vertical front face t2. The cams are all of the same length and shape and are adapted to actuate switching mechanism carried by the car as the latter moves from floor to Hoor. This switching mechanism may be attached tothe roof of the car or at any other suitable location, and consists essentially of two bell cranks o and o', each carrying a roller o2 at one end, adapted to engage the cams t, while the otherl end of each bell crank is adapted to make and break connection respectively, with two pairs of contacts u and u. Each of the lbell cranks carries an armature core 'c which extends into a solenoid coil w which, when energized, tends to draw the arms of the switches toward each other and hold them out of contact with their respective contact points. As the car moves past ,the various cams z, the rollers 02 of the switch levers, if not restrained by the solenoid up, will, under the action of springs o', ride against the inclined ends and face of the cams. The two switch arms are spaced apart so that the rollers o2 will be separated by a distance equal to the length of the front face t2 of the cam, and the cams are so placed in the shaft that when the platform of the car is on an exact level with the floor. the two rollers 02 will bear against the respective extremities of the front face of the cam in which position the contacts u and u will both be open. Should the car come to a stop with its platform slightly below or above the floor, one

an operator in the car will irst be eX- plained. When operating this way, the switch F is in the position shown in the diagram. lVe will assume the car to be gO- ing up at its normal high speed. In this condition the control lever c is in the left end of the upper slot of plate c', and the blade c2 connects contacts 17 and 1S together. At the instant of throwing the lever to the position stated, the lever 22 of the time switch was in connection withv contact 25 so that current flowed from the main wire 15 by wire 40 to lever 22 of the time switch, contact 25, wire 41, switch F, wire 42` wire 43, contact 20, bridge 19, contact 21, wire 44, switch F, wire v45, high speed switch coil, high speed switch frame, wire 46, wire 47- and wire 48 to the main 14. This closed the high speed switch and opened the circuit between that switch lever and the contact 39. At the same time, a branch of the current flows from the wire 42 to the contact 17 of the car controller, blade c2, Contact 1S, wire 49, wire 5,0, upswitch coil, wire 51, up limit switch g, wire 52, one of the coils of the non-interfering magnet s3, wire 53, frame of high-speed switch, and back to main wire 14 as before traced, thus closing the up-switch and connecting the contacts 32, 33 and 34, whereupon the current branches at the point 54 where it enters the up-switch and iiows by wire 55 to point 32, bridge 31, point 33, wire 56, wire 101, circuit breaker coil, wire 57, contact 13, wire 58, contact 59, high speed switch lever, wire 46 and back to ymain 14 as before traced, thereby closing the circuit breaker and connecting contacts 29 and 30 by means of the bridge 28. It is to be observed at this point that the current which enters the bridge 31 of the rip-switch from the wire 55, has no outlet through Contact 34 because the wire which leads from that contact through the frame ot'- the master magnet s4 and a coil on the slow speed switch, is open-circuited at the point 39. This prevents the low speed Aswitch and the low speed mechanism from being actuated during the run at high speed. The closing of the lip-switch and of the circuit breaker throws current into the motor, one-phase being fed from wire 16 through one up-switch lever, wire 60, frame of down-switch andl wire 61,' another from main wire 15 through frame of the circuit breaker and a lever of the circuit breaker to wire 62, the other upswitch lever, frame of the up-switch and wire 63, and the third-phase from main wire 14 bythe other circuit breaker lever and wire 64. At the same time that the motor receives current, the time switch solenoid 24 is energized by circuits 65, 66,

Y bridged across wires 61 and 63 of the motor,

as shown. This causes the lever 22 of the time switch to lift, breaking connection with contact 25 and making connection with 26, the latter connection being ineffective, however, since the circuit leading therefrom to the low speed switch frame by wire 67, is open. Upon the breaking of the circuit at the Contact 25, the original starting circuit which included the wire 40 and the lever 22, was opened, and in order to maintain the circuit breaker, the up-switcli and the high speed switch closed after the break at 25, the connection between the contacts 29 and 30 at the circuit breaker was established.l This, it will be seen` supplies current from wire 40 (or main 15) to contact 29, bridge 28, contact 30, wire 68, wire 41, switch F wire 42 to the controller.

The car continues upward under these conditions until a landing is to be made, whereupon the lever c isv thrown to the neutral point where all of the controlling circuits are opened to stop the car. The operator anticipating that the car will not stop exactly at the landing but (say) somewhat below the same, immediately moves the lever C through the cross-slot in plate c and into the left end of the low speed slot. But this does not necessarily shift the speed changing device at once, although the circuits are thereby prepared for the shift.

-The time switch lever 22 is in the meantime moving down and not until it breaks with 26 and connects with point 25 will the desired speed change take place. This interval of time permits the motor to lose its momentum and come to a full stop, or nearly so before the current is again sent through it. When lever, 22 iinally connects with point 25 current from line 15 enters the controller, as before, and this time cannot pass out through wire 43 and bridge 19 because the latter has'opened that circuit by the movement of the lever c into the slow speed slot. Hence the high-speed switchremains open with its lever in connection with contact 39. Current however flows from contact 18 by wire 49 and wire 50 to close the up-switch, as before, whereupon a circuit is established by wire 55, contact 32, contact 34, wire 69, master magnet frame s4, wire 70, low-speed switch coil, wire 71, contact 39, high speed switch lever and wire 46 to the main line. This closes the low s eed switch and permits current to flow rom main wire 15 by wire 72, low speed switch lever, wire 73, solenoid 10 of the speed changing device, wire 74, the other low speed switch lever, wire to main wire 14, thus energizing solenoid 10, causing it to move lever 7 to the left and thrown in the low speed gearing or mechanism, allowing cut-out 12. to connect with contact 13. Establishing this last connection permits current to flow from the bridge 31 of the up-switch through'contact 33 to the circuit breaker, thence by wire 57, cut-out 12, wire 48 to line, and close the circuit breaker. This starts the motor, the circuits being the same as before traced. At the same time, the time switch solenoid 24 is energized, as before, the starting circuit is broken at 25 and a connection is made between the lever 22 and contact 26. This vconnection affords a path for current from the main wire 15, by wire 40, lever 22, contact 2G, wire 67, the other coil on the low-speed switch, lowspeed switch frame and lever to wire 7 5 and lto main line 14. As long as current flows through either of the coils of the low-speed switch, the latter will be held closed. Since the circuit breaker must be closed while running at. both speeds, the high-speed switch ,accomplishes its closing by the movement of its lever to closed position and the lever 12 does the same thing when the low-speed switch is closed.

The car will now moveupward at, say, one-tenth of its normal speed due to the introduction of the change speed device, and in traveling thus slowly, the operator is able to gage the movement so as to bring his car to a stop on an exact level with the floor. When he throws the lever c to neutral to stop the car, he thereby denergizes the second coil of the low-speed switch, since at the neutral position the up-switch .is open, but the low-speed switchnevertheless remains closed and the low-speed switchin because the other coil of the low-speed switch remains energized due to the fact that lever 22 of the time switch has not yet reached the lower end of its travel and separated from contact 26. In the period while said lever is moving downward, the.

motor loses its momentum and comes to a full stop, and in the meantime, the low gear remainsin mesh because solenoid 10 continues to be energized. If solenoid 10 bei came denergized at or about the same instant that the motor circuit was opened, the car would be driven during the period while the motor was losing its momentum, on the direct or high gear. With solenoid 10 remaining energized and the starting circuit open until the motor entirely stops, the op erator is certain toget accurate responses to his manipulation of the controller. It

should be understood, however, that it is not.

essential to bring the motor to a stop before the low-speed mechanism is thrown in, since if the speed of the motor isreduced to the rate at which its motion is communicated to the machine' through the low speed gear, the latter may be thrown in at the instant when the speed of the motor corresponds to the speed at which the machine runs under the reducing gear. For this reason the dash-pot of the time switch may be adjusted to permit of the energizing of the solenoid 10 at the critical moment.

While the car is movingup and down at high speed in the shaft under the control of the operator in the car, it is desirable that the rollers 02 which cooperate with the cams along the shaft, be out of operative position so that they will not be continually striking the cams needlessly. For this reason the solenoid u' is, under these conditions, energized by a current leading from wire 41, by wire 76, through the solenoid and wire 77 to contact 78 of the high-speed switch and the lever-of the high-speed switch to wire 46.

In the description of the operation above given the movements of the car at both high and low speed were in an upward direction and consequently the upswitch was effective in both cases. It will, however, be understood that in case either of these movements were in a down direction, the down-switch would be utilized instead of the up-switch, and it is considered unnecessary to trace these circuits since they are ordinary electric elevator control circuits.

7e will now refer to the operation of the system under the push button control. It will be understood that in periods when the car is often in use, it is advantageous to have f an operator on the car, and likewise during periods such as on holidays or through the .night when traffic is not so heavy, it is deswitch F must be in the position shown in dotted lines on the diagram. le will now suppose'that the car is at the second floor landing and that a person on the ufirst floor wishes to use the car. With the car at the secondtloor landing, the regulator or selector G is in the condition shown in the diagram, that is to say, the bellcrank corresponding to the second iioor is being held in the neutral position by the engagement of its roller with the cross slotg4. Inthis neutral position, the circuit controlled by the push button on the second Hoor is open at the bell-crank and the car cannot be moved byl operation` of that push' button. When the button on the first iioor is pushed, the following circuit is closed; from main wire 15, by wire 40, switch lever 22, contact 25, wire 41, switch F, wire 79 to they gate switch on the car, which is then assumed to be closed, 4wire 80, to theA stop button switch p3 in the car, which is also assumed to be closed, wire 81, wire 82 and successively through the other door switches throughout the building, thence by wire 83 to the master magnet coil s, thence by wire 84 to the coil of first floor magnet s, wire 85 to push button on the first floor, the common wire 86 to all of the push buttons, thence by wire 87 to the back contact 88 of the non-interference magnet s3, the lever of said magnet I14. Thus the hand-operated push button closes the corresponding floor magnet s and the master magnet s4. The closure of the first floor magnet s creates a branch circuit leading from the coil of said magnet through its lever, thence by wire 90 toone of the contacts on the first Hoor bell-crank of the regulator G since that bell crank is then in closed circuit position; the circuit continues through the lever, thence by wires 91 and 92 to the point 93 where the circuit branches again and leads by wire 94 to the magnet coil of the down-switch, thence by wire 95 to the down limit switch r, wire 96, wire 52 to one coil on the non-interference magnet s, wire 53 to the high-speed switch frame and wires 46, 47 and 48 to the main line. This circuit just traced energizes the downswitch, determining the direction of movement of the car and energizes the non-interference magnet. which then breaks the con` tact at 88 which opens the circuit of all other push buttons and prevents interference with the movement of the car by another person. At the branching point 93 another circuit 4at the same time leads by wire 97 to'the contact 36, thence by the bridge 35 to the contact 38, by wire 98, wire 69, frame of the master magnet s4, lever of said magnet which is then against its front stop, wire 99, switch F, wire 45, high-speed switch coil, frame of high-speed switch and wire 46 back to the main line. The high-speed switch now being closed and the contact 39 being broken, the low-speed switch is thrown out of circuit and a circuit through the circuit breaker is closed through the high-speed switch lever as follows: from the bridge 35 on the down-switch lever, by point 37, wire 101, coil of the circuit breaker, wire 57, point 13, wire 58, point 59, high-speed switch lever and wire 46 to line. The downswitchand the circuit breaker now being closed, the motor is started as heretofore eX- plained, and the solenoid 24 of the time switch is energized, breaking the contact at 25 and making the contact with 26, the latter Contact, however, being ineffective, since during the high speed running, whenthe vcircuit breaker closes and the solenoid 24 is energized, which is followed by the breaking of the contact at 25, a new feeding circuit is established by the bridging of the points 29 and 30 by the circuit breaker. This introduces the wire 68 which then supplies currentfrom the main to the wire 41 instead of the wire 40 which in the first instance supplies current to wire 41 through the lever 22 and contact 25. It will be noted that. incidentally upon the closure of the high-speedV switch, the solenoid w on top of the car is energized through the circuit wires 76, 77 leading respectively from wire 41 and contact 78, thus holding the rollers o2 out of the path of the cams in the shaft.

The car now moves downward toward the first floor at high speed and when it reaches the first floor, the bell crank switch .on the regulator corresponding to the first iioor and being indicated by I, is moved to open the circuit by the fact that its controlling roller enters the cross-passage g4 of the cam track. All circuits are thereby opened, and the solenoid w holding the switches on the top of the car being denergized, the rollers 02 drop into contact with the cam t at the first floor. If the car is on an exact level with the floor, the two rollers will be at the respective ends of the face t2 of the cam and both of the levers o and 0 will be held out of engagement with the respective contacts u and u. But in case the car stops at a level above or belowthe landing, then one .of the rollers 02 will be upon one of the inclined faces t of the cam and the correspondinv pair of contacts u or u will be closed. f e will assume that the car stopped below the level of the landing in rwhich case the contacts u would be closed. This partially establishes a new starting circuit which is finally completed when the lever 22 of the time switch lowers into contact with the point 25. .The appreciable interval which is provided by theaction of this timeswitch affords time for the motor to sufiiciently lose its momentum to permit it to start in a reverse direction at the reduced speed predetermined by the speed changing device. When the time switch eventually closes the contact 25, it will be seen that a circuit to throw in the speed changing device, the low-speed switch, the 11p-switch and the circuit breaker will then be established. It will be necessary to trace only a part of this circuit, since the remainder is the same 'as that which has already been traced in connection with the hand-operated switch in the car. The circuit leads from the wire 15 by wire 40 to the time switch lever 22, contact 25, wire 41, switch F, wire 79, contacts u, wire 102 which then unites with the wire 49 from point 18 on the hand control and leads thereafter through the circuits heretofore traced in order to accomplish the energizing of the up-switch, the throwingin of the speed changing device to the lowspeed position through the action of the low speed switch, the energizing of the circuit breaker and the time switch. `The lcar is then moved upward slowly until the roller 02 opens the circuit at the point u which it does when the roller leaves the inclined face tand passes onto the front face t2 of the cam. Opening the circuit at u opens the upswitch and the circuit breaker and denergizes the coil 24 of the time switch. The low-speed switch, however, continues to hold the speed changing device at low speed because of the delay in the lever 22 of the time switch breaking contact with the point 26. This insures that the entire momentum of the motor will be consumed while the slow speed gear is in.

We claim:

1. In an electric elevator, a speed changing device interposed between themotor and the car, controllingr means wherebyl said device may be shifted, and means whereby said controlling means will not be eii'ected to shift from one speed ratio to another until the lapse of a predetermined interval of time.

2. In an electric elevator, a speed chang ing device interposed between the motor and the car, controlling means whereby said dey, vice m'ay be shifted,an electro-magnetic mechanism adapted to hold the speed changing device in active condition, and an automatic switch adapted to hold the circuit of said mechanism closed for a predetermined period after the circuit of the motor has been opened.

P. In an electric elevator, the combination of a motor, a car driven thereby, a change speed device interposed between the motor and car, a lowv speed switch having two windings one of which is in the motor control circuit, a time switch controlling a circuit including the other of said windings, a circuit controlling said speed changing device and itself controlled by said low speed switch and a controller on the car whose cir cuits are controlled by said time switch.

4. In an electric elevator, the combination of a driving motor, a speed changing device, an electric .circuit by which both the 1 motor and device are thrown out of operation, a manually opera-ted circuit controller in said circuit and an automatic retarding device adapted to delay the effect of the operation of the controlling switch upon the speed changing gear.

5. In an electric elevator, the combina-v tion of a change speed device, an electrof magnetic device for shifting the same, a controlling circuit for said electro-magnetic de vice and automatic retarding means for delaying the effect of 'a manipulation of the controlling circuit to shift said gear.

6. In an electric elevator, the combination of a drivingr motor, a manuallyoperated control switch on the car, a starting circuit, an automatic Itime cut-out, a speedvuchanging gear and an electric circuit controlling the shi fting of said gear, the time cut-out beingI ade pted to successively control the speed shifting and starting circuits. v

7 In an electrically controlled elevator, a speed changing device interposed between the motor and the car, a manually operated controller in the car, an automatic control actuated from the iloor'push buttons, and means whereby the speed chan 'ng devlce may be actuated by either of sai controls.

K8. 'In an electric elevator, the combination of a driving motor, a car driven thereby, aI

speed changing device and include a 'switch for stopping and starting the motor and an automatic time switch controlling the actuation of the speed changing device with reference to the speed of the motor.

9. In an electric elevator, the combination of a high speed switch, a low speed switch, a manual car controller and a car operated floor level controller, and means whereby said low speed switch may be actuated by either controller.

'10. In an-electric elevator, the combination of car operated and manually operated controlling devices, a motor starting switch, a high speed switch, a low speed switch, means whereby either controller may energizethe high speed switch, and means whereby the high speed switch when actuated will incapacitate the low speed switch. ll. Inan electric elevator, the combination of high and low speed mechanisms, a floor leveling switch carried by the car, devices in the shaft cooperating with said switch to bring the car to an accurate landing, and means whereby when the high speed obtains the floor leveling switch is held outof coperative relation to the devices in the shaft. l

l2. In an electric elevator control system, the combination of a high speed mechanism, a low speed mechanism, an automatic push button controlling mechanism, a master switch normally holding the low speed mechanism operative, and means whereby the actuation of a push ,button'in the control system will render the low speed mechanism inoperative and the high speed mechanism operative.

13. In an electric elevator, the combination of a `driving motor, an elevator car, a change speed gearing interposed between said car and motor, and means for shifting4 said gearing and means, rendered operative by the location ofthe car when it stops, for actuating said shifting means. i

14. In an electric elevator, the combination of a driving motor, an elevator car, a change speed mechanism interposed between the motor and car, a controller for starting and stopping the car and means for shifting the change speed mechanism, said meansbeing dependent for its operation upon the relative position of the car anda landing when the car stops.

In witness whereof we subscribe our sig-

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