ELEVATOR FLOOR LEVELING SYSTEM

• US 3,749,203 A
• Filed: 08/11/1971
• Issued: 07/31/1973
• Est. Priority Date: 08/11/1971
• Status: Expired due to Term

• Current Assignee: William R. Hoelscher
• Original Assignee: William R. Hoelscher
• Inventors: Hoelscher, William R.
• Primary Examiner(s): Gilheany, Bernard A.
• Assistant Examiner(s): Duncanson, Jr., W. E.
• Application Number:
  US05/170,841
• Time in Patent Office: 720 Days
• Field of Search: 187/29 318/480,640
• US Class Current: 187/291
• CPC Class Codes: B66B 1/40 and for correct levelling at landings

Abstract

A system for landing and leveling elevators or otherwise controlling the spacial relationship between two relatively movable objects. The system incorporates a pair of vanes that include a light transmitting opening along their long dimension. A light bulb movable with the elevator car traverses the space between the two light vanes and a pair of light sensors view the light bulb through the openings in the vanes. The vane openings are tapered from a relatively large to a relatively narrow end and this taper is in opposite directions on opposite ones of the pair of vanes. The relative displacement position between the light vane and the sensor-bulb position, that produces an equal signal on each sensor, comprises a null, and this null position is set to correspond to the desired location for the car. The null is developed by comparing the signals in a differential amplifier, any deviation from the null position will produce an amplified error signal that may be used to input an electronic elevator drive control means or other means for controlling relative motion. Also incorporated in the system is an error modifying means for increasing the error signal when there is a relative acceleration between the parts of the system. The signal is also increased and at an increasing rate with the persistence of an error for a period of time. Thus, the system closely follows the movement of the elevator with respect to the hoistway and maintains its position accurately at the desired floor level through inputs to the elevator drive means.

Claims

1. A system for automatically stopping or leveling the floor of an elevator car with respect to a predetermined point in the elevator hoistway comprising:

displacement signal means for varying the amount of radiation reaching sensor means from a source means when said sensor means is moved relative to said displacement signal means;

said sensor means having an output that is substantially proportional to the amount of said radiation;

sense means for determining the direction said source means is displaced from said displacement signal means; and

drive control Means for controlling the velocity of said car in response to the output of said sensor means.

2. The system of claim 1 wherein:

said displacement signal means comprises a vane means having an opening that transmits a variable amount of radiation at a plurality of relative locations of said source means and said vane means.

3. The system of claim 2 wherein:

said vane means comprises a pair of relatively planar vanes having openings that generally taper along their length;

the narrow end of said openings being located at opposite ends of said pair of vanes.

4. The system of claim 3 wherein:

said source comprises a light bulb with an elongated filament, the filament being substantially parallel to the width dimension of said opening.

5. The system of claim 4 wherein:

said sensor means comprises a pair of photosensitive elements mounted on said car;

said light bulb being mounted on said car; and

said vanes being mounted on said hoistway to straddle the path of travel of said light bulb.

6. The system of claim 1 wherein:

said sensor means comprises a pair of sensors;

said displacement signal means for causing the amount of radiation reaching one of said pair of sensors to vary in amplitude in the opposite direction of the variation in amplitude of the other of said sensors.

7. The system of claim 6 wherein:

the difference in the amplitude of said signals comprises an error signal; and

said drive control means for responding to said error signal to reduce said signal by causing relative movement between said displacement signal means and said sensors.

8. The system of claim 7 including:

error signal modifying means for producing an increase in said error signal when the signal displacement means and said sensor means are relatively accelerated.

9. The system of claim 7 including:

error signal modifying means for increasing said error signal by increasing amounts, if said error signal persists for a period of time.