Product News - Limit Switch Allows Operators To Work Safely Around Robots

Limit Switch Allows Operators To Work Safely

Around Robots

Asimov's first law of robots maintains that a robot may not harm a human. The new Robot Base Limit System enforces that law.

The new system fits into the base of a robot, monitoring the robot's angular  position about its vertical axis. Used in conjunction with an employee-monitoring safety mat or light curtain, it cuts power to the robot only if the robot attempts to move outside its user-defined work zone when operators are present. It also mutes the safety devices while the robot operates within its designated work zone.

The system can be adapted to work with a variety of robots and can monitor up to three zones. It is adjustable to provide 15 to 180 deg of robot work zone and implements a dynamic restricted envelope per ASME R15.06-1992.

The system includes a mechanical limit switch assembly that mounts to the stationary base of the robot, a slotted aluminum circular cam tray that attaches to the robot's rotating flange and switch-actuating circular cams that mount on the trays at rotation boundary locations. The cams, which are adjustable in 7.5-deg increments, trip the mechanical switch if the robot rotates beyond the defined work zone.

The limit switch assembly is a double-changeover switching system made up of six limit switches actuated by stainless steel plungers. Each switch has a repeatability of ±0.02 mm.

Positive-break, force-guided contacts are rated for 5 million operations. The switch assembly has an anodized aluminum housing sealed to IP65 and can tolerate temperatures ranging from -41 to 176 F.

Prices start at $2500; the system is available as an after-market product and to robot OEMs.

Balluff Inc.
Florence, KY