Robot emergency stop circuit

• US 5,212,433 A
• Filed: 08/13/1991
• Issued: 05/18/1993
• Est. Priority Date: 12/19/1989
• Status: Expired due to Fees

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Yasuyuki, Shimoda
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/720,870
• Time in Patent Office: 644 Days
• Field of Search: 318/560-636, 364/513, 364/191, 200/52 R, 200/1-6, 901/3, 901/5, 901/8, 901/12, 901/13, 901/15, 901/18-23, 395/88-99
• US Class Current: 318/568.13
• CPC Class Codes: B25J 13/00 Controls for manipulators programme controls B25J9/16; control in general G05
• CPC Class Codes: B25J 13/02 Hand grip control means handles or pedals for crane control B66C13/56; for measuring the force applied to control members G01L5/22; hand-held casings for switching devices, e.g. joy-sticks H01H9/0214
• CPC Class Codes: B25J 19/06 Safety devices
• CPC Class Codes: B25J 9/1674 characterised by safety, monitoring, diagnostic
• CPC Class Codes: H01H 2300/026 Application dead man switch: power must be interrupted on release of operating member
• CPC Class Codes: H01H 2300/028 Application dead man switch, i.e. power being interrupted by panic reaction of operator, e.g. further pressing down push button
• CPC Class Codes: H01H 9/0214 Hand-held casings

Abstract

A robot emergency stop circuit for bringing the robot to an emergency stop through a deadman switch installed on a teaching control device while the robot is being taught behavior patterns through the teaching control device. The deadman switch (DM1) causes the robot to operate according to commands received from the teaching control device as long as a pressure applied by a finger remains within a specified range. When the finger pressure becomes lower or higher than the specified range, a magnet switch in a servo amplifier (2) is turned OFF, bringing the robot to an emergency stop. Accordingly, if the robot should unexpectedly move, causing an operator to take an unintended action such as flinging the teaching control device away or holding it tightly, and thus apply an abnormal pressure to the deadman switch (DM1), then the contact point of the deadman switch (DM1) is shifted from the middle point of three contact points, thus turning the switch OFF. Accordingly, the robot can be stopped even if the operator takes an unintended action when a hazardous situation occurs.

Claims

1. A robot emergency stop circuit for bringing a robot being supplied power to an emergency stop while said robot is being taught behavior patterns using a teaching control device issuing instructions, said robot emergency stop circuit comprising:

a deadman switch connected to the teaching control device, said deadman switch including;

a 3-position contact switch having first, second and third contact positions; and

a conductive element contractual with said first, second and third contact positions responsive to pressure applied to said deadman switch,

said deadman switch supplying said robot with the power in response to the pressure applied by a user enabling the robot to receive the instructions and operate in accordance with the instructions issued by said teaching control device when the pressure applied by the user remains within a specified range connecting said conductive element to said second contact position and connecting the power supply to the robot, and

said deadman switch stopping the supplying of the power to said robot when the pressure applied by the user becomes one of lower than said specified range connecting said conductive element to said first contact position and higher than said specified range connecting said conductive element to said third contact position, disconnecting the power supply from the robot.

2. A robot emergency stop circuit according to claim 1, further comprising a switch connected to and denergizing said deadman switch, and

wherein when said deadman switch is deenergized by said switch, the robot will not stop even when the pressure applied by the user to said deadman switch is one of lower and higher than the specified range.

3. A robot emergency stop circuit according to claim 1, further comprising a switch connected to said deadman switch, and

wherein when said deadman switch is placed in an off condition by the user, said switch is activated for maintaining the off condition until said deadman switch is reset.

4. A robot emergency stop circuit according to claim 1, wherein said deadman switch is pressure biased to place said conductive element in connection with said first position.