Detection of people relative to a passenger conveyor with a capacitive sensor

• US 9,272,882 B2
• Filed: 12/18/2009
• Issued: 03/01/2016
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Soldner, Nicholas C., Hsu, Arthur C., Veronesi, William A., Siewert, Bryan R., Gschwendtner, Gero, Ercan, Abdullah, Senger, Alois
• Primary Examiner(s): Crawford, Gene
• Assistant Examiner(s): Randazzo, Thomas
• Application Number:
  US13/515,446
• Publication Number:
  US 20120247919A1
• Time in Patent Office: 2,265 Days
• Field of Search: 198/322, 198/323
• US Class Current: 1/1
• CPC Class Codes: B66B 25/00 Control of escalators or moving walkways walkways of variable speed type B66B21/12; handrails of variable speed type B66B23/26; of general application G05
• CPC Class Codes: B66B 25/006 Monitoring for maintenance or repair for security reasons B66B29/005
• CPC Class Codes: G01R 15/16 using capacitive devices

Abstract

A system for detecting a person relative to a passenger conveyor includes a driving circuit for supplying an oscillating drive signal to a first electrode of a capacitive sensor configured to produce an electric field toward a second electrode in response to the oscillating drive signal. A detection circuit is connected to the capacitive sensor, and produces an output as a function of the capacitance of the capacitive sensor, such that the detection circuit senses a change in capacitance of the capacitive sensor, such as when a person enters the electric field between the first and second electrodes. A controller is responsive to the change in capacitance sensed by the detection circuit to selectively adjust an operation mode of the passenger conveyor.

Claims

1. A system for detecting a person relative to a passenger conveyer having a structural component and a passenger riding area, the system comprising:

a driving circuit for supplying an oscillating drive signal;

a capacitive sensor having a first electrode configured to produce an electric field toward a second electrode in response to the oscillating drive signal;

a detection circuit connected to the capacitive sensor that senses a change in capacitance of the capacitive sensor and produces an output as a function of capacitance; and

a controller responsive to the detection circuit output to selectively adjust an operation mode of the passenger conveyor;

wherein the first and second electrodes are disposed on portions of the passenger conveyor structural component on opposite sides of the passenger riding area, and wherein a change in capacitance is caused by the presence of a person in the electric field between the first and second electrodes;

the driving circuit further comprising;

an oscillator for creating an oscillating drive signal;

an amplifier connected to the oscillator to amplify the oscillating drive signal;

an impedance matching network connected between the amplifier and the capacitive sensor; and

a mode selector operable to drive the capacitive sensor in a selected mode.

2. The system of claim 1, wherein the oscillator has a frequency of 100 kHz to 1 MHz.

3. The system of claim 1, wherein the oscillator has a frequency of 100 kHz to 150 kHz.

4. The system of claim 1, wherein the detection circuit comprises:

a comparator configured to sense the change in capacitance of the capacitive sensor and produce the output as a function of capacitance of the capacitive sensor.

5. The system of claim 1, wherein

the passenger conveyor structural component is a balustrade, and the first electrode comprises a conducting surface of the balustrade on one side of the passenger riding area, and the second electrode comprises a conducting surface of the balustrade on the opposite side of the passenger riding area.

6. The system of claim 5, wherein the balustrade is formed from a non-conducting material and a conductive material is disposed on a surface thereof on opposite sides of the passenger riding area.

7. The system of claim 6, wherein the non-conducting material is glass.

8. The system of claim 6, wherein the conductive material is adhered to the surface of the non-conducting balustrade.

9. The system of claim 6, wherein the conductive material is formed integrally with the non-conducting balustrade.

10. The system of claim 6, wherein the conductive material is divided into multiple sections.

11. The system of claim 10, wherein a multiplexer connects the sections to transmit the output of the capacitive sensor to the detection circuit.