The tooling piece are transferred from a first conveyor line (16) with two parallel belts onto a second transverse conveyor line with an endless belt (32). A locking chassis is fixed to the first line and a lifting installation raises the transfer belt on the transverse line. The lifting unit comprises a section (26) with an air channel (28) and a runner (24) on which passes the transfer belt. The runner slides in the section so it can be raised relative to the locking chassis. A fixed piston (25) in the section has a vertical air passage (56) communicating with the air channel through a channel (57). The upper face of the vertical air passage discharges into a piston cavity (58) forming an air chamber. The piston is locked by a screw (54) and is sealed on its lower side by a toroidal joint (55) and has a sealing joint (59) housed in an appropriate groove. The runner has a lateral collar (29) having holes (60) housing compression springs (30). The lifting system is adaptable to different sizes of conveyor lines.
