Access safety solutions for hazardous robot cells

Citation

(1999), "Access safety solutions for hazardous robot cells", Industrial Robot, Vol. 26 No. 3. https://doi.org/10.1108/ir.1999.04926cad.006

Access safety solutions for hazardous robot cells

Keywords Robots, Safety

Fortress Interlocks has integrated its Amgard modular interlocking system with a wide range of robust trapped key equipment to produce access safety solutions for hazardous robotic cells (see Plate 6).

Plate 6 Fortress Interlocks has integrated its Amgard modular interlocking system with a range of robust trapped key equipment to produce access safety solutions for hazardous robotic cells

In the modern production plant, robotic systems increase productivity but are essentially unintelligent systems. For successful operation, industrial robots rely on the continued role of man. Regular access to robot cells is required on a day to day basis, for local programming, maintenance, servicing, cleaning, part loading and fine tuning adjustments. With man and machine working so closely together, serious safety problems are posed by the fast, unpredictable movements and considerable operating force of robots following complicated programs.

Perimeter guarding provides the most effective safeguard for industrial robots, but guarding alone is not a safe solution if strict access controls are not enforced. Sophisticated interlocking systems can impose sequential control on the operations necessary for safe access, eliminating all hazards before operators can enter.

Trapped key interlock systems operate on the principle that actions performed in the correct sequence are safe. A specially constructed lock mechanism traps the access key until associated machinery or plant is in a predetermined condition. Removing the key from the lock secures the state of the equipment to which that lock is fitted.

Fortress has combined this principle with a range of solenoid controlled Amgard interlocks. Appropriate units from the Amgard range ensure that access keys are not released until robots reach the end of their run down cycle. This ensures that personnel cannot enter while robots are still slowing down and prevents damage to plant and equipment from sudden mid-cycle halts.

To prevent the robot being restarted while personnel are inside the enclosure, the manual drive or teach-mode key is only released when the robot is safely isolated. The operator takes this key into the enclosure while work is carried out. Automatic operation cannot be restored until the key is returned to the external unit.

For further information contact: Malcolm Sharp, Fortress Interlocks Limited, 148-150 Birmingham New Road, Wolverhampton, WV4 6NT, UK. Tel: +44 (0) 1902 403546; Fax: +44 (0) 1902 353003; E-mail: sales@fortress-interlocks.co.uk