US1058308A - Safety slow-down and stop motion for electric elevators. - Google Patents

Description

\ D. LARSON.

SAFETY SLOW DOWN AND STOP MOTION FOR ELECTRIC ELEVATORS.

APPLIGATIOK FILED JULY 5, 1910.

Patented A ris, 1913.

5 Woe W501 UNITED STATES PATENT OFFICE.

DAVID LARSON, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SAEETY SLOW-DOWN AND STOP MOTION FOR ELECTRIC ELEVATORS.

Specification of Letters Patent.

Patented Apr. 8, 1913.

Application filed July 5, 1910. Serial No. 570,257.

To all whom it may concern:

Be it known that I, DAVID LARSON, a subject of theKing of .Sweden, residing at Yonkers, in the county of Westchester and State of New York, have invented a new and useful Improvement in Safety Slow-Down and Stop Motions for Electric Elevators, of which the following is a specification.

My invention relates to an elevator slowdown device which is adapted to be used in connection with electric elevators.

One (if the objects of my invention is to provide means for slowing down the elevator motor at any desired place or places.

Another object is to provide adjustable electro responsive meansfor effecting the slow-down action at any desired speed of the motor.

Other objects will appear hereinafter, the novel combinations being set forth in the appended claims.

In the accompanying drawing my invention is diagrammatically shown as employed in connection with an electric elevator.

Broadly speaking my invention is to pre vent the elevator car from traveling at excessive speed at any point or points, and especially at or near the limits of travel of v the car. If the speed is not too high when the slow-down positions are reached, the slow-down apparatus will not be required, and will not be operated. I

Referring to the drawing, the motor M operates the car C and the counterweight W by means of the cable 13 which passes about the traction drums 11 and 12. Current is supplied .to the armature of the motor M through the main switch S, potential switch P main conductors 14, 15, reversing switch R or R, st-artingresistance X, motor leads 16, 17, and to the winding of the brake B by the operation of the car controller switch K. The starting resistance X is controlled by the accelerating magnet A and the circuitof the magnet winding has the hatchway switches 18 and .19 connected in series with it. Both the accelerating magnet winding and the brake magnet winding receive current through the auxiliary reversing switch contacts 1 or r. A cam 20 on the elevator car is adapted to engage the slow-down switches 18 and 19, and the limit switches 21 and 22. The potential switch winding is connected in series with the normally closed limit switches 21 and 22. A hand lever H is commonly provided manually to open the potential switch. The motor field is connected by the conductors 23 and 24 to the main conductors 14-15.

Connected to the motor leads 16 and 17 are the .conductors 25 and 26. Conductor 25 leads through the resistance Y to contact 27, and conductor 26 is connected to contact 28, so that when the contacts 27 and 28 are joined, a circuit whichincludes the resistance Y is closed in parallel with the motor armature, or in other words forms a shunt circuit for the armature. The magnet 29 is operative when energized to join the contacts 27 and 28. The terminals of this magnet winding 29 are connected by conductors 33 and 34 to the contacts 31 and 32, and the first named terminal also has a connection by way of resistance 36, conductor 35, to the slow- down hatchway switches 36 and 37. These switches 36 and 37 are normally open and are adapted to be closed by a grooved projection 38 carried by the car, and when closed at the same time the controller switch K is in an operating position, complete a circuit from the main conductor 14 through the switch K and byway of conductor 39 or 40 andslow-down switch 36 or 37 to the conductor 35 and through resistance 36 to one terminal of the said magnet winding 29. Contact 32 is connected by means of conductor 41 to the other main conductor 15, so that when the two contacts 31 and 32 are joined at the time one of the hatchway switches 36 or 37 and the controller switch circuited and the resistance 36 prevents a short-circuit connection between the main conductors 14 and 15. \Vhen, however, the contacts 31 and 32 are separated, a circuit is closed from one main to the other through the magnet winding 29, which causes the switch contacts 27 and 28 to be united and the shunt resistance Y to be inserted in parallel with the motor M. The contacts 31 and 32 are separated when the magnet E is operatively energized, and the magnet winding 30 is subject to the potential of the motor armature by reason of its connections through conductors 43 and 26 to the motor lead 17 and through conductor 42 to motor lead 16. When the potential across the motor armature is of a prescribed value the that is, it will be operatively energized at any given speed of the motor.

' In order that my invention may be more readily understood, let it be assumed that the hand lever in the car 0 is turned to the right to energize reversing switch R and cause the motor to lower the car. The accelerating magnet A is energized and the resistance X is short-circuited. As the car nears a predetermined point, such as the limit of travel of the car, the cam 20 engages the hatchway switch 19 and opens the circuit of the accelerating magnet winding, causing the resistance X to be inserted in the motor armature circuit. As the car continues, the grooved projection 38 closes the slow down hatchway switch 37 and if the speed of the motor is sulficiently high the magnet E is energized, causing the magnet winding 29 to receive an energ1zing current and to close the shunt circuit through the resistance Y1 This exerts a powerful braking effect upon the motor, reducing the speed so that the car is not traveling at too great a speed when the cam 20 opens the limit switch 22, breaking the energizing circuit through the potential switch winding. If the speed of the car and the motor is not too great at the time the switch 37 is closed the slow down shunt will not be necessary and the magnet E is not energized. In this respect the action is entirely relative and automatic.

Although I have thus set forth the preferred embodiment of my invention, it is evident that those skilled in the arts to which this appertains may make various changes without departingfrom the spirit and scope of the invention.

What I claim and desire to secure by Letters Patent of the United States is 1. In an electric safety for elevators, the combination of a motor, a car, an electro-responsive means dependent upon the speed of the motor for energization, and operative only when the s eed of the motor is above a predetermined value and at a predetermined point or points in the travel of the car to establish a dynamic circuit and thereby effect the slowing down of the motor-before the elevator car reaches either limit of travel.

2. In an electric safety for elevators, the combmation of a motor, an elevator car, and electroresponsive means dependent upon the counter-electro-motive force of the motor for energization and operative only when the car is at a predetermined point in its travel to establish a dynamic brake circuit and thereby slow down the car and the motor when the speed thereof is too high.

3. In'an electric safety for elevators, the combination of a motor, an elevator car, resistance for a shunt circuit, means for closing the said circuit parallel to the motor armature, a magnet dependent for energization upon the counter-electromotive force of the motor, and means cooperating with said magnet and operative to effect the operation of the said circuit closing means only asthe elevator car approaches either limit of travel.

4. In an electric safety for elevators, the combination of a motor, resistance for a motor shunt circuit, means operative only at predetermined points in the operation of the elevator for closing the said circuit, and a magnet dependent for energization upon'thc speed of the motor and operative to effect the energization of the circuit closing means only when the speed of the motor is too great at said predetermined points.

5. In an electric safety for elevators, the combination of a motor, switches in the elevator hatchway closed by the car, resistance for a motor shunt circuit, means for closing the circuit and a magnet subject to the same potential as the motor armature energized when the motor attains a predetermined speed and effective to operate the circuit closing means when the speed of the elevator car is too great at the time a switch is closed by the car.

6. In an electric safety for elevators, the

combination of a motor, resistance for a motor shunt circuit, a switch to close the said circuit, a magnet normally open circuited for closing the switch when energized, hatchway switches closed by the elevator car, and an adjustable magnet connected to the motor armature terminals and operative to direct an energizing current to the other magnet when the speed of the motor is too high at the time a hatchway switch is closed.

7 In elevator safety apparatus, the combination of a car, a motor, hatchway slow down switches normally open, means in conjunction with the car for closing the switches, resistance for a circuit arallel with the motor armature, a magnet or closing the said circuit parallel with the armature, and an adjustable magnet energized when the speed of the motor reaches a predetermined limit and operative when energized at the time a hatchway switch is closed to direct an energizing current through the other magnet to elfect the slowing down of the motor.

8. In elevator safety apparatus, the combination of a car, a motor, hatchway switches normally open, means in connection with the car for closing the switches, resistance for a motor armature shunt circuit,

a magnet to close the said circuit, a short circuit comprising a switch connected across the winding of said magnet, an adjustable ma et connected across the motor armature an operative when energized to open said short circuit switch and direct acurrent through the other magnet when one of the hatchway switches is closed, and resistance in series with the circuit closing magnet winding. i

9. In elevator safety apparatus, the combination of a car, a motor, hatchway switches normally open', means in connection with the car for closing the switches, resistance for a motor armature shunt circuit, a magnet to close the said circuit, a switch normally closed to short-circuit the said magnet winding and operative to energize the said magnet when opened at the time one of the hatchway switches is closed, resistance to prevent a short-circuit when one of hatchway switches .is closed when the last named switch is closed and in circuit with the magnet winding when the switch is open, and an electro-magnet connected across the motor armature and operative when energized to open the normally closed switch.

10. In. an electric elevator, the combination of a motor, reversing switches for the motor, a controlling switch in the elevator car, normally open hatchway switches closed by the car, resistance for a motor armature shunt circuit, a magnet operative when energized to close the said clrcuit, the magnet winding being in circuit which includes a hatchway switch and the controlling switch when the latter is in an operating position, and a magnet connected across the motor armature operative when energized to direct current through the other magnet winding.

11. In elevator safety apparatus, the combination of a mot-or, reversin switches for the motor, a car controller switch, normally open hatchway switches closed by the car, a motor accelerating magnet, hatchway switches normally closed in series therewith, resistance for a motor armature shunt,

means in connection with the car for opening the closed switches to deenergize the motor accelerating magnet, and means to close a shunt circuit includin the said resistance when the speed of t e car is too great at the time the hatchway switches are opened by the car.

12. The combination in an elevator, of a motor, a car, retarding mechanism for the motor, means to automatically efi'ect the operation of said retarding mechanism when the car reaches a predetermined point in its travel, and mechanism to prevent the operation of said retarding)mechanism while the speed of the motor is elow a predetermined value.

13. In an elevator, a -motor, a car, a dynamic brake circuit for the motor, mechan1sm operated by a moving part of the elevator to cause the said brake circuit to be established, and means controlled by the speed of the motor to prevent the said clrouit from being established.

' In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

- DAVID LARSON.

Witnesses:

EDWARD I-I. STEELE, GEORGE D. Ross.

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