Industrial robot

An industrial robot for use in an atmosphere containing an inflammable or explosive gas, comprising:

• a robot assembly including a stationary robot component and a plurality of movable robot components, at least a part of said stationary robot component and said movable robot components having therein airtight chambers which communicate with each other;
• means for supplying pressurized air to said airtight chambers to maintain the interior of said airtight chambers at a pressure higher than a predetermined pressure level, which is higher than that of the external atmosphere to prevent seepage of said inflammable or explosive gas into said airtight chambers;
• electric motors for driving and moving said movable robot components, said motors disposed within said airtight chambers;
• a programmable controller for supplying electric power to said motors and for controlling said motors in accordance with a predetermined program, said controller disposed outside of said atmosphere of inflammable or explosive gas and electrically connected to said motors through electric cables arranged in said airtight chambers and hermetically sealed conduit connected to said stationary robot component;
• and;
• a plurality of pressure switches, arranged in said airtight chambers and electrically connected to said controller, for detecting a pressure in said airtight chambers and transmitting a motor-stop signal to said controller when the pressure in said airtight chambers drops below said predetermined level, such that, in response to said motor-stop signal from said pressure switches, said controller stops the supply of electric power to said motors.