CH614679

A feed device for flexible workpieces comprises a clamp for securing two workpieces together. The clamp is movable along a guide in line with the displacement of the workpieces past a sewing station by the sewing machine feed. A retarding force is continuously applied to the clamp to maintain a tension on the workpieces as they are drawn through the sewing station preferably by a turbine driven by compressed air. The retarding force is a continuously applied restoring force which can be switched between a relatively substantial force designed to return the clamp to its starting position and a tension force which can be reduced to substantially a zero value.