Abstract: An assembly machine has a frame defining at least one work station, a transfer mechanism for feeding a succession of workpieces one at a time through the station, and at least one tool at the station movable between an operative position engageable with the workpiece in the station and a retracted position out of engagement with the workpiece in the station. A push-pull operating element has an outer end connected to the tool and an inner end connected to a cam carried on an output of a drive mounted on the frame for displacing the tool between its positions synchronously with feeding of the workpieces through the station. A pneumatic spring mounted on the frame is braced against the tool and has a compartment pressurizable to urge the tool into the operative position. The back compartment is continuously pressurized with a gas under a generally constant pressure.

Abstract: An assembly apparatus has a plurality of stationary work stations spaced apart in a transport direction extending downstream from a holding station, a plurality of holders each adapted to carry a respective workpiece and each formed with at least one downwardly directed entrainment tooth, an upstream conveyor for feeding the holders in a row to the holding station, and a downstream conveyor extending downstream from the holding station past the work stations and including a belt formed with external teeth meshable with the teeth of the holders. A blocking element at the holding station can move between a position preventing downstream movement of the holders past the holding station and a position permitting such downstream movement.