US1833126A - Elevator control device - Google Patents

Description

NOV. 24, 1931.7 J cE ELEVATOR CONTROL DEVICE Filed Sept. 30, 1929 Patented Nov. 24, 1931 Jami: nrciapor cHIoAoo;,1LLINoIs,.AssIoNonion?omn-nALn 'ro Emerson. com

PANYOE:AMERICLVOE'CHICAGO,ILLINOIQiN;CORPORATION OFILLINOIS:

nnnvaroa ooNraoL DEv Io J Application,filedseptember 30,11929 serial no; 396,174. a k

My invention relates to elevators and has foriits principalpurposean improvement smoothnessv in operation particularly in" changesotspeed of the elevator hy the employment of-an' inertia governing device;

1n the operation of'elevators; if they are accelerated or slowed down suddenly either'in starting or stopping or" in intermediate. 7 speeds, theresultantstrain' on the mechanism 1s very great'andrthediscomfort to passengers in thetelevator and danger" of injuring are also great.

My invention contemplates the elimination of these difficulties bythe provision, in combination with the cable sheave shaft, of 21111111- ertia governing device-which tends tooppose changes in speed'of theelevator at all'times and thusmakes these changesless abrupt:

geared drives for elevators.

Other beneficial objects accomplished' 'by' this invention include improvements ac curacy'a'ndsmoothness of floor stops, smooth- 5 eroperati'oni'n changesin speed' where atwospeed power unit is; employed, the-eliminag tion of the necessity forcertain starting conti'ol devices on the driving moton'and themaintenance of-the entire equipment in betv I willdescribeone form which the inven tion may takeby reference'to the-accompanying drawings wherein Fig. 1- is ai side view ofanelevatordriving mechanism'fequipped with my invention;

' Fig: 2isa'view 0f" ig.'.1'. p Referring now in detail 'to' the drawings, I

haveinot shown the elevator car orits convators are ,moved;* operate upon" the 1 cable f dmnn-or-sheavecwhi'cliis carried upon a shaft 3& 6 mounteddnsuitablebearings asat 'T ter conditionv by reduction of. strains" due-to? jerks in startingand stopp ng'the elevator.

an les to Fig: 1 as indicated by theline 353-:

In the embodiment shown, the drive-shaft 6' which-'operatesata relatively low speeds'ay intlie neighborhood of 40 R. P; M." is driven fronia pr1meinover9in the form ofan elec- V trio motorusuallyof' the alternating current 51:

squirrel cage type; In some of theinstallations made-,- they have the speed of about 1000 R. P. M. The motor is geared" directly to the'shaftfi by means of'shaft 10, worm 1'1, andworm-ge'ar 12 shownmost clearly in Fig; cc III-this mannert'he sheave 5' is-rotate'dto" move thejelevator up'anddown. 7 l

There is provided upon the shaft 10 'abrake" drum-13 and cooperatingbra'ke'shoesas indi' cated at 14 tof'orma:drum brake utilized in 05* stopping the elevator. However, if only such a brake is" used, the'play'betweenthe worm 'andgeanll and12gives a considerable amountrofhacklash'in stopping which-results in communicating asudden j ar or-bl'ow tothe sheave 5 and ithrough this and the operating c'a'ble totlie operating car; Moreover,1any suddennchange in-speed of the drivingmotor is directly communicated through the-sheave 5'to-theelevator'car. It has been-proposed 7'5 to utilize a braking device'upon the shaft '6 in the nature of a-drum brake, but, owing to the relatively low' speed of theshaftt, such a braking device isnot' very successful in eliminating the'jars-andjerks' dueto' back lash and changes in'speed; and the bralieof itself brings another disturbing effect, be cause in bringing the'car to a stop the application of this brake-to the slow moving'sha-ft V 6' usually results inthe gripping of the drum V by the' brakeshoes; after the-speed has retakenon the line of duced to a certain point and thus againjerk the c-arin'stopping: In order to eliminate this" jerking and" strains on the mechanism, I provide arelativelyhigh speed rotating device in conjunction-with the shaftfi which serves as-an' inertia governor to oppose sudden changes in the speed-of the sheave 5L Thisinertia governor" consists of a drum or wheel 15' mountedupon' a shaft 16w-hich is connected" for instance by 'means of the reduction gearcomposed of pinion 17 and gear 18 to shaft" 6';- Oneratio 'ofthe speed of shaftldto'the speed of shaftfi whichl have found veryef fective, is a ratio of approximately five to one. That is to say, for each revolution of shaft 6, the shaft 16 and its associated drum 15 must rotate five times. This is, of course, only illustrative and any other ratio may be used so long as the speed of the inertia device 15 is sufficient to accomplish its purpose.

Now in starting up the motor 9, the drum 15 naturally will offer considerable opposition clue to its inertia and in this way too sudden a start is avoided because the drum 15 must be brought up to speed as the speed of rotation of shaft 6 increases. Having reached a definite speed, the drum 15 and shaft 16 naturally oppose due to their inertia any change in speed; and, if for instance the brake 14 is applied, the backlash in the gears 11 and 12 will not seriously jerk or reduce the speed of the shaft 6 because they will be opposed by the inertia of the high speed drum 15. Similarly any change in speed will be opposed by this inertia governing device.

In order to further insure the safety of the elevator and aid in making quick stops without inconvenience or discomfort in the elevator, I provide in conjunction with the drum 15 a second braking means consisting of the brake shoes indicated at 19 and operated by suitable control mechanism 20 which may be of any suitable type. In stopping the car, therefore, both brakes 1A and 19 may be applied to slow down the shaft 6. Both brakes being applied through the reduction gearing to shaft 6, the shaft will naturally be reduced to "a very low speed before the speed of the drums 13 and 15 is lowered sufficiently to permit the shoes to grip the drums and stop them suddenly.

I have found that by the use of this device much smoother acceleration and deceleration of the elevator will be obtained, and that owing to the elimination of jerks and ars the entire mechanism remains in condition much better than it does without the device.

I have also found that, while it is good practice to employ a primary resistance in the circuit of the squirrel cage motor where the car speed is greater than seventy-five feet per minute to avoid jerks in starting, such precautions are not necessary when the present invention is employed because the inertia of the drum 15 opposes the torque developed by the motor and assures a smooth start.

As an example of the effect of the dual braking control in combination with the high speed drum 15, I have found that it is possible to stop the sheave 5 running free by the use of both brakes within a quarter turn of the sheave after they are applied. With the brake 1 1 not used, the brake on the drum 15 stops the sheave within three-fourths of a turn, while, if the sheave is allowed to run with the motor shut ofi, it requires three turns before it will stop. Thisgives a very good comparison of the relative effects of the braking device.

Another advantage that has been noted in the use of this invention lies in the fact that, when a two-speed motor is used and the current is shut off while changing from one speed to another, the inertia governing device maintains the speed of the elevator with but very little drop during the short interval requiredto change from one speed to the other and eliminates any jerks due tolthe shifting of speeds.

While I have described one specific form of the invention, itis obvious that various modifications may be made therein without departing from the scope ofthe invention. It is believed that from the above description the construction and operation of the device will be clear to those skilled in this art.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. A drive mechanism for elevators and the like comprising a relatively high speed prime mover, a drive shaft having connection with said prime mover whereby it is driven therefrom at a reduced speed, and a stabilizing rotatable member positively connected to said drive shaft to be driven therefrom at high speed.

2. A drive mechanism for elevators and the like comprising a relatively high speed prime mover, a drive shaft having connection with said prime mover whereby it is driven therefrom at a reduced speed, and a stabilizing rotatable member positively connected to said drive shaft to be driven therefrom at high speed, said member having a brake cooperating therewith whereby to stop said shaft.

3. A drive mechanism for elevators and the like comprising a relatively high speed prime mover, a drive shaft having connection with said prime mover whereby it is driven therefrom at a reduced speed, and a stabilizing ro tatable member positively connected to said drive shaft to be driven therefrom at high speed, said prime mover and said member having brakes thereon for stopping said shaft.

4; In a device of the character described, a high speed prime mover, a drive shaft having a cable drum thereon, a worm and gear connection between the prime mover and drive shaft whereby to operate the drive shaft at a low speed, a second shaft having a positive drive connection with said drive shaft whereby it is driven at high speed from said drive shaft, and a fly-wheel on said second shaft.

5. In a device of the character described, a high speed prime mover, a drive shaft having a cable drum thereon, a worm and gear connection between the prime mover and drive shaft whereby to operate the drive shaft at a low speed, a second shaft having a reducing gear connection with said drive shaft whereby it is driven at high speed from said drive shaft, and a fly-wheel on said second shaft.

6. In a device of the character described, a high speed prime mover, a drive shaft having a cable drum thereon, a worm and gear connection between the prime mover and drive shaft whereby to operate the drive shaft at a low speed, a second shaft having a reducing gear connection with said drive shaft whereby it is driven at high speed from said drive shaft, a fly-vvheel on said second shaft, and a braking means for said fly-wheel.

7. In an elevator power unit including a motor, a drive shaft geared to said motor to rotate at slow speed, and a cable sheave on said shaft, means for preventing sudden changes in the speed of rotation of said sheave comprising a shaft having a wheel thereon, and means connecting said shafts for driving said last named shaft at high speed from said drive shaft.

8. In an elevator power unit, a cable sheave, a shaft upon which said sheave is mounted, a motor shaft geared to said shaft for driving said sheave, a third shaft geared to said first named shaft by a reduction gear so as to be driven therefrom at a much higher speed, said third shaft having a fly wheel and a drum brake thereon.

9. In an elevator power unit, a cable sheave,

a shaft upon which said sheave is mounted, a motor shaft geared to said shaft for driving said sheave, a third shaft geared to said first named shaft by a reduction gear so as to be driven therefrom at a much higher speed, and drum brakes on said motor and third shafts. 10. In a driving mechanism for elevators and the like including a drive shaft and a prime mover for rotating said shaft, an inertia governing device for smoothing out the operation of the elevator during changes in speed and direction comprising a rotatable drum positively connected to said shaft through a reduction gearing giving the drum a speed more than three times as great as the speed of the shaft. y

In witness whereof, I hereunto subscribe my name this 20th day of Sept. A; D. 1929. JOSEPH RICE.

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