Hand tool step drive mechanism, crimping pliers provided with such a mechanism and crimping method

A hand tool step drive mechanism (10), such as a pair of crimping pliers, which mechanism is intended to be fixed in a hollow body (1) which has a rear end (1a) and a front end (1b), characterized in that said mechanism includes, with reference to the normal position of use and to the direction of drive (F1):

• a rack (2) which is intended to be mounted in the hollow body (1) so as to slide between a starting position (Pi) and an end position (PF) and which has:
• two longitudinal edges (2a, 2b), upper (2a) and lower (2b) respectively,
• a first toothing (3) having rearwardly angled teeth (3a) which is arranged on one of the two longitudinal edges (2a, 2b);
• a second toothing (4) having rearwardly angled teeth (4a) which is arranged on the other of the two longitudinal edges (2b, 2a);
• a front end (2c);
• a lever (5) which is intended to be mounted so as to pivot in the hollow body (1) between a maximum tightening position (PSM) and an initializing position (PDEV), said lever comprising a hollow upper end (5a) which receives a torsion spring (6) which bears against said hollow upper end (5a) of the lever and bears against a so-called “drive” ratchet (7), which is intended to be mounted so as to pivot in the hollow body (1), in front of the hollow upper end (5a) of the lever, and is provided with a crossbar (7a) which engages between the teeth (3a) of the first toothing (3);
• a so-called “locking” ratchet (8) which is intended to be mounted so as to pivot in the hollow body (1) and is provided with a crossbar (8a) which engages between the teeth (4a) of the second toothing (4), a compression spring (9) being arranged bearing against the locking ratchet (8) and bearing against a stop (2d) which is situated on a rear end (2e) of the rack (2).