Elevator switch monitoring device

Patent metadata

Field	Value
Publication number	US-12565401-B2
Application number	US-202117163944-A
Country	US
Kind code	B2
Filing date	Feb 1, 2021
Priority date	Feb 1, 2021
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

An illustrative example embodiment of a switch monitoring device includes a controller configured to command a switch to enter at least one of a conducting state and a non-conducting state. A monitoring circuit conducts current when the switch is in the conducting state. A comparator provides an output indicating a relationship between a voltage of a selected portion of the monitoring circuit and a threshold voltage. The controller determines a condition of the switch based on the output of the comparator and the command.

First claim

We claim:

1 . A switch monitoring device, comprising:
a controller configured to issue a command for a switch to enter at least one of a conducting state and a non-conducting state; a monitoring circuit configured to conduct current when the switch is in the conducting state; and a comparator configured to provide an output indicating a relationship between a voltage of a selected portion of the monitoring circuit and a threshold voltage; wherein the controller determines a condition of the switch based on the output of the comparator and the command.

2 . The switch monitoring device of claim 1 , wherein
the relationship between the voltage of the selected portion of the monitoring circuit and the threshold voltage indicates whether the switch is in the conducting state or the non-conducting state; the controller determines whether a current state of the switch corresponds to the command; and the controller provides an indication that the switch is not functioning properly when the current state of the switch does not correspond to the command.

3 . The switch monitoring device of claim 1 , wherein
the output from the comparator has a first value when the voltage of the selected portion of the monitoring circuit exceeds the threshold voltage; the output from the comparator has a second value when the voltage of the selected portion of the monitoring circuit equals or is below the threshold voltage; the first value indicates that the switch is in the non-conducting state; and the second value indicates that the switch is in the conducting state.

4 . An elevator system component comprising the switch and the switch monitoring device of claim 1 .

5 . The elevator system component of claim 4 , wherein the elevator system component is a brake including a coil and the switch establishes a connection between the brake and a power supply for energizing the coil when the switch is in the conducting state.

6 . The elevator system component of claim 4 , wherein the elevator system component is a daisy chain including a plurality of switches.

7 . The switch monitoring device of claim 1 , wherein the output of the comparator has a first value when the switch is closed or in the conducting state and a second, different value when the switch is open or in the non-conducting state.

8 . The switch monitoring device of claim 1 , wherein:
the controller determines whether a current state of the switch corresponds to an expected state based on the command provided by the controller, and if the switch is commanded to be open and the output of the comparator indicates that the switch is closed, the controller determines that there is a fault condition or malfunction of the switch; and/or when the output of the comparator indicates a switch state that corresponds to a commanded switch state, the controller provides an indication of a health or proper operation of the switch.

9 . The switch monitoring device of claim 1 , wherein:
the switch monitoring device is associated with a brake of an elevator machine, and wherein the brake includes a coil energized by a power supply and that operates to lift or engage the brake; the switch comprises a first switch and including a second switch, wherein the first switch and second switch are provided to control whether the brake is lifted or engaged depending on the command; and the first switch and second switch are provided in series to establish a connection between the brake and the power supply for energizing the coil when the first switch and the second switch are in the conducting state.

10 . The switch monitoring device of claim 9 , wherein the monitoring circuit comprises a first monitoring circuit for the first switch and a second monitoring circuit for the second switch, wherein the first monitoring circuit and the second monitoring circuit each include a comparator that has a voltage source, resistors, a Zener diode, and a capacitor.

11 . The switch monitoring device of claim 10 , wherein, when one of the first switch or the second switch is open or in the non-conducting state, the resistors of the first monitoring circuit or the second monitoring circuit serve a current limiting function, the Zener diode limits the voltage at the selected portion of a respective one of the first monitoring circuit and the second monitoring circuit when the one of the first switch or the second switch is open, and a respective capacitor of the first monitoring circuit or the second monitoring circuit filters out transient voltage oscillations during a state transition of the one of the first switch or the second switch, and wherein a voltage value is higher at the selected portion of the respective one of the first monitoring circuit and the second monitoring circuit than the threshold voltage when the one of the first switch or the second switch is open.

12 . A method of monitoring a switch, the method comprising:
using a controller to issue a command for the switch to enter at least one of a conducting state and a non-conducting state; conducting current through a monitoring circuit when the switch is in the conducting state; determining a relationship between a voltage of a selected portion of the monitoring circuit and a threshold voltage; and using the controller to determine a condition of the switch based on a determined relationship and the command.

13 . The method of claim 12 , wherein
the determined relationship indicates whether the switch is in the conducting state or the non-conducting state; the controller determines whether a current state of the switch corresponds to the command; and the method includes using the controller to provide an indication that the switch is not functioning properly when the current state of the switch does not correspond to the command.

14 . The method of claim 12 , wherein
determining the relationship comprises using a comparator that compares the voltage of the selected portion of the monitoring circuit and the threshold voltage; a comparator output has a first value when the voltage of the selected portion of the monitoring circuit exceeds the threshold voltage; the comparator output has a second value when the voltage of the selected portion of the monitoring circuit equals or is below the threshold voltage; the first value indicates that the switch is in the non-conducting state; and the second value indicates that the switch is in the conducting state.

15 . The method of claim 12 , wherein the switch is part of an elevator system component.

16 . The method of claim 15 , wherein the elevator system component is a brake including a coil and the switch establishes a connection between the brake and a power supply for energizing the coil when the switch is in the conducting state.

17 . The method of claim 15 , wherein the elevator system component is a daisy chain including a plurality of switches.

18 . The method of claim 12 , wherein determining the relationship comprises using a comparator that compares the voltage of the selected portion of the monitoring circuit and the threshold voltage, and wherein a comparator output has a first value when the switch is closed or in the conducting state and a second, different value when the switch is open or in the non-conducting state.

19 . The method of claim 12 , wherein determining the relationship comprises using a comparator that compares the voltage of the selected portion of the monitoring circuit and the threshold voltage, and including:
determining whether a

Assignees

• Otis Elevator Co

Inventors

• Guo ben
• Li Zhenhong

Classifications

• B66B1/463

  Touch sensitive input devices · CPC title

• H01H9/54

  Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere · CPC title

• G01R31/3278

  of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002) · CPC title

• H01H9/167

  Circuits for remote indication · CPC title

• G01R31/3277

  of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches · CPC title