AU599842B2

AU599842B2 - Elevator car position monitoring system

Info

Publication number: AU599842B2
Application number: AU24035/88A
Authority: AU
Inventors: Kenneth Lloyd Muller
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1987-10-19
Filing date: 1988-10-19
Publication date: 1990-07-26
Anticipated expiration: 2008-10-19
Also published as: AU2403588A

Description

I r, g COMMONWEALTH OF AUSTRALIA t FORM PATENTS ACT 1952 COMPLETE SPECIF CATION FOR OFFICE USE: Class Int.Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: 'o oRelated Art: 0 O 0 Q CfO This document contains tL amendments made cI,.

Section 49 and is contc f. i pirinting i^L^*h s a w K l °""Name of Applicant: Address of Applicant: Address of Applicant: OTIS ELEVATOR COMPANY Ten Farm Springs, Farmington, Connecticut 06032, United States of America SActual Inventor: 0 00 Kenneth Lloyd Muller Address for Service: SHELSTON WATERS, 55 Clarence Street, Sydney o Complete Specification for the Invention entitled: s i "ELEVATOR CAR POSITION MONITORING SYSTEM" The following statement is a full description of this invention, including the best method of performing it known to us:- 1 Complete of PI 4936 dated 19th October, 1987 00, :0 0

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000 00 0 An elevator car position monitoring system for monitoring the position of an elevator car in an elevator shaft.

Most elevator control systems need to know where, in its particular shaft, an elevator car is. This information is necessary so that the control system can respond correctly to the users' demands.

In the past control systems kept track of an elevator car's position by the relative monitoring of the distance travelled by the car from a specific reference position. Commonly the reference position was at the 0 bottom of the shaft, where a cam switch fixed to the 0 0 building was operated by the presence of the car, Other o positions in the shaft were determined by incrementing or decrementing a position counter according to an impulsed signal generated by a proximity sensor, for example as the car moved up and down the shaft the proximity sen3or 0 would provide a pulse at each landing.

The disadvantage of this system is that the position d0 information can be corrupted by electrical noise, or even lost completely if continuous electricity supply is not maintained. In such instances the elevator car, through separate control logic, is forced to return to the "known" position at the bottom of the shaft.

According to the present invention there is provided an elevator car position monitoring system for monitoring the position of an elevator car in an elevator shaft comprising:- 00 0 C 00 040 0, 00I 00a 040 2 i m- 0 000 a plurality of coded members located at predetermined positions in an elevator shaft, each such member being coded differently from the others; a code reading means mounted on an elevator car and arranged to receive signals containing the respective codes from the coded members when they are passed as the car travels up and down the shaft; and means for deriving position indications related to said predetermined positions from the received codes.

Preferably said coded members comprise at least two vertical rows of discrete elements; and said code reading means comprise at least two detectors, each for sensing the presence of one of the elements, the detectors being horizontally-adjustably spaced apart.

Advantageously a method for providing car location signals to an elevator control system involves the steps of:a) mounting at least two vertical rows of elements at a preset distance from a floor location; said rows of elements forming a coded member; b) mounting on an elevator car at least two detectors, each detector for sensing the presence of one of the elements, and adjusting the horizontal distance between the detector, to align the detectors with the said vertical rows.

The invention will now be described by way of example only with reference to the accompanying drawing which illustrates an embodiment of the invention.

3 41-- 1 In this figure elevator car 1 is shown in a notional elevator shaft. Mounting bracket 2 is attached to the top of car i, and connected to bracket 2 are two magnetic sensors 3 and 4. Magnetic sensors 3 and 4 are connected also to a trailing electrical cable 5 which hangs suspended in the shaft. Connected to the wall of the shaft at predetermined locations are a series of regularly spaced coded members 6. Each coded member 6 has a column of vertically arranged magnets 7 down its front face. These magnets are binary coded by virtue of S their orientation, and the code of each column is unique Sno with respect to the codes of the columns on the other coded members 6 in that shaft. In the figure six magnets 7 are shown in each column.

As elevator car 1 mnves up and down the shaft it passes coded members 6, and magnetic sensor 3 passes 1 within the magnetic fields of magnets 7. In this way the 0 unique code of each column of magnets 7 is read as the elevator passes by.

A control means, not shown, may be situated at the other end of cable 5. Alternatively the control means may be located inside car i. In any event the control means derives a position indication, related to the predetermined location of each coded member 6, from each received code.

A second vertical column of magnets 8 may be positioned on each coded member 6 adjacent to the column of coded magnets 7. In the embodiment shown these may be -4read by magnetic sensor 4 simultaneously to magnets 7 being read by sensor 3. Magnets 8 are not coded but provide clock information to the control means in order to simplify the logic required to correctly interpret the coded signals, and thereby make the system independent of elevator speed variations. Since each coded member 6 is uniquely coded relative to the other members in that shaft, the absolute position of the elevator may be derived by the control means each time the elevator car passes a coded member.

The resolution of the system is variable to operational requirements and depends on the shaft's o 0 0o length and the number of coded members, which in turn o depends on the number of data code bits provided on each 00 coded member. For instance a four-bit code will allow 24, or sixteen, uniquely coded members. In a 60 meter 0 8shaft this provides for resolution of approximately 3.75 4 meters. In the same shaft the five-bit code system would provide a resolution of approximately 1.9 meters. Of course there is no necessity for the coded members 6 to be spaced equidistantly from each other, and they may be arranged so as to provide greater resolution at selected locations in the shaft.

It should be appreciated that there is no requirement for the magnets 7 or 8 to be disposed vertically, however this arrangement requires only two magnetic sensors. Of course, clock magnets may be disposed in line with the coded magnets in which case 5 L a only one magnet sensor will be required.

It should also be appreciated that the invention :s not restricted to using magnetically coded members, and any other type of coded members may be employed. For instance members emitting sonic, radio, infrared or light waves. However, it is preferred that the coded members are passive.

g o o a o Ii Sr f1 6

Claims

2. An elevator as described in Claim i, characterized in that:- )606 06i said coded members comprise at least two vertical Q 0: rows of discrete elements; and said code reading means comprise at least two detectors, each for sensing the presence of one of the o0 elements, the detectors being horizontally-adjustably 0 spaced apart.
3. A method for providing car location signals to an elevator control system involving the steps of:- a) mounting at least two vertical rows of elements at a preset distance from a floor location; said rows of elements forming a coded member; b) mounting on an elevator car at least two detectors, each detector for sensing the presence of one of the elements, and adjusting the horizontal distance -7- A T A"-S between the detector, to align the detectors with said vertical rows.
4. An elevator substantially as hereinbefore described with reference to the accompanying drawing. A method substantially as hereinbefore described with reference to the accompanying drawing. DATED this 18th day of October, 1988 OTIS ELEVATOR COMPANY 0 0o Attorney: PETER HEATHCOTE on o Fellow Institute of Patent Attorneys of Australia 0 0 1 of SHELSTON WATERS 8 0 4- 0 a 00 11, i-8