Wireless emergency stop systems, and corresponding methods of operating a wireless emergency stop system for a machine safety interface

Patent metadata

Field	Value
Publication number	US-2021003981-A1
Application number	US-202017026878-A
Country	US
Kind code	A1
Filing date	Sep 21, 2020
Priority date	Jun 30, 2017
Publication date	Jan 7, 2021
Grant date	—

Abstract

Exemplary embodiments are provided of wireless emergency stop systems. In an exemplary embodiment, a wireless emergency stop system includes a machine safety device wired to a machine stop circuit for stopping operation of a machine when the machine stop circuit is activated. The machine safety device includes a wireless communication interface. The system also includes multiple personal safety devices. Each personal safety device includes a wireless communication interface for wireless communication with the machine safety device, and an emergency stop switch. The emergency stop switch is configured to, when activated, transmit an emergency stop signal to the machine safety device to trigger an emergency stop of the machine. The machine safety device is configured to maintain wireless connections with more than one of the multiple personal safety devices at the same time. Example methods of operating a wireless emergency stop system are also disclosed.

First claim

What is claimed is:

1 . A wireless emergency stop system comprising:
a machine safety device wired to a machine stop circuit for stopping operation of a machine when the machine stop circuit is activated, the machine safety device including a wireless communication interface; and multiple personal safety devices, each of the multiple personal safety devices including:
a wireless communication interface for wireless communication with the machine safety device; and
an emergency stop switch configured to, when activated, transmit an emergency stop signal to the machine safety device to trigger an emergency stop of the machine;
wherein the machine safety device is configured to maintain wireless connections with more than one of the multiple personal safety devices at the same time when more than one of the multiple personal safety devices are wirelessly connected with the machine safety device; and wherein each personal safety device is configured to wirelessly disconnect from the machine safety device without triggering an emergency stop of the machine in response to said personal safety device receiving activation of at least one operation input on said personal safety device, where the at least one operation input is distinct from activation of the emergency stop switch of said personal safety device and distinct from a loss of wireless communication of said personal safety device with the machine safety device thereby allowing said personal safety device to be wirelessly disconnected from the machine safety device without triggering an emergency stop of the machine.

2 . The system of claim 1 , wherein:
the machine safety device is configured to stop operation of the machine when an internal fault of the machine safety device is detected; the machine safety device is configured to stop operation of the machine when one or more of the multiple personal safety devices currently connected with the machine safety device loses wireless communication with the machine safety device; the machine safety device is configured to stop operation of the machine when one or more of the multiple personal safety devices currently connected with the machine safety device has an activated emergency stop switch; and the machine safety device is configured to stop operation of the machine when a fault is detected at one or more of the multiple personal safety devices currently connected with the machine safety device.

3 . The system of claim 1 , wherein, when none of the multiple personal safety devices are wirelessly connected with the machine safety device, the machine safety device is configured to maintain normal operation of the machine when an internal fault of the machine safety device is not detected.

4 . The system of claim 1 , wherein, when one or more of the multiple personal safety devices are wirelessly connected with the machine safety device, the machine safety device is configured to maintain normal operation of the machine when all of the one or more connected personal safety devices have wireless communication above a signal quality threshold and none of the one or more connected personal safety devices have an activated emergency stop switch.

5 . The system of claim 1 , wherein each of the one or more connected personal safety devices are configured to transmit continuous periodic messages to the machine safety device, and wherein:
the machine safety device is configured to stop operation of the machine in response to failing to receive the continuous periodic messages from one of the one or more connected personal safety devices after a specified period of time; the machine safety device is configured to stop operation of the machine when an internal fault of the machine safety device is detected; the machine safety device is configured to stop operation of the machine when one or more of the multiple personal safety devices currently connected with the machine safety device loses wireless communication with the machine safety device; the machine safety device is configured to stop operation of the machine when one or more of the multiple personal safety devices currently connected with the machine safety device has an activated emergency stop switch; and the machine safety device is configured to stop operation of the machine when a fault is detected at one or more of the multiple personal safety devices currently connected with the machine safety device.

6 . The system of claim 1 , wherein each of the one or more connected personal safety devices are configured to transmit continuous periodic messages to the machine safety device, and wherein the machine safety device is configured to stop operation of the machine in response to failing to receive the continuous periodic messages from one of the one or more connected personal safety devices after a specified period of time.

7 . The system of claim 1 , wherein activation of the at least one operation input on said personal safety device includes activation for a specified period of time, and wherein said personal safety device comprises a force sensor and/or a tilt sensor configured to detect a fall event by an operator and to transmit the fall event to the machine safety device.

8 . The system of claim 1 , wherein each personal safety device is configured to wirelessly disconnect from the machine safety device without triggering an emergency stop of the machine in response to a user pressing an unlinking button of the personal safety device for a specified amount of time.

9 . The system of claim 1 , wherein:
the machine safety device includes one or more safety relays, each of the one or more safety relays connected to the machine stop circuit; the machine safety device is configured to open one or more of the safety relays to stop operation of the machine when an emergency stop is triggered by one of the multiple personal safety devices; and the machine safety device is configured to maintain the one or more safety relays in a closed state to allow operation of the machine while an emergency stop is not triggered by any of the multiple personal safety devices.

10 . The system of claim 1 , wherein each personal safety device is configured to:
identify a user via an identification protocol; and allow the personal safety device to connect to the machine safety device only when an authorized user is identified via the identification protocol.

11 . The system of claim 10 , wherein each personal safety device comprises:
the identification protocol, which includes at least one of an RFID card and a biometric identifier; and authorization rights are associated with the authorized user, the authorization rights stored locally within the personal safety device.

12 . A wireless emergency stop system comprising:
a machine safety device wired to a machine stop circuit for stopping operation of a machine when the machine stop circuit is activated, the machine safety device including a wireless communication interface; and at least one personal safety device including:
a wireless communication interface for wireless communication with the machine safety device; and
an emergency stop switch configured to, when activated, transmit an emergency stop signal to the machine safety device to trigger an emergency stop of the machine;
wherein the at least one personal safety device is configured to wirelessly disconnect from the machine safety device without triggering an the emergency stop of the machine in response to the at least one personal safety device receiving activation of at least one operation input on the at least one personal safety device, where the at least one operation input is

Assignees

• Cattron North America Inc

Inventors

• Stagg David

Classifications

• G05B9/02 Primary

  electric · CPC title

• G05B19/048 Primary

  Monitoring; Safety · CPC title

• G05B2219/24003

  Emergency stop · CPC title

• G05B19/0425

  Safety, monitoring · CPC title

• G08C17/02

  using a radio link · CPC title