SAFETY DEVICE FOR GUARDED MACHINERY

摘要

This invention relates to a safety device comprising a first unit which is adapted for connection to a fixed structure of machinery and which includes electrical switching means for controlling power to the machinery. A second unit is adapted for connection to a door, cover or guard and includes manually operable keying means which is movable between successive OPEN, OFF and ON positions and is engageable with and disengageable from said first unit when in the OPEN position and co-operates with the first unit to prevent separation of the two units when engaged with the first unit and moved to the OFF and ON positions. The keying means further controlling operation of the switching means when both units are engaged so that power is connected to the machinery only when the keying means is in the ON positron; and delay means which is operative on movement of said keying means from the ON to the OFF position and which then acts for a limited time to positively prevent movement of the keying means from the OFF to the OPEN position.