PARIS--Believing that people adapt better than robots, a growing number of French manufacturers are using operator-assisted manipulators to move objects around on assembly lines.

French carmakers have invested in operator-assisted material handling equipment since the 1990s. "When workers no longer have to contort themselves to make a weld on the hidden part of a door, less rewelding is required at the end of the line," says Marc Haury, health and safety manager at the Peugeot factory in Mulhouse, France.

Peugeot uses pneumatic manipulators from Sapelem (Angers, France) to lift and move loads of up to 660 pounds. Each manipulator is equipped with electronic balance control, so the operator supports only a few pounds. When the load is raised, it is automatically weighed, and a microcontroller adjusts the pneumatic pressure accordingly. In certain cases, it can be mounted on a rail to extend its range.

Matra Automobiles (Romorantin, France), which assembles the Renault Espace van, uses dozens of spring-driven mechanical balancers from ARDC (Paris). The balancers enable assemblers to rapidly position 132-pound doors with minimal effort. "The advantage of the spring is its speed," says Jean-Marc Oriole, one of the inventors of the ARDC balancer. "For a load heavier than 60 pounds, it reacts in 0.001 second, instead of around 1 second for an air piston, so the operator doesn't notice anything."

For more information on operator-assisted manipulators, contact the French Technology Press Office at 312-222-1235.