Patent ID: 7614133

Claim:
A method for manufacturing a jack or hydraulic, pneumatic and/or oleopneumatic cylinder comprising a cylindrical tubular body ( 4 ) with a bottom ( 1 ) fastened to a first end of the tubular body ( 4 ), a head ( 5 ) fastened to a second end of the tubular body ( 4 ), and a piston ( 2 ), integral with a rod ( 3 ), configured to slide within an inside of the tubular body ( 4 ), comprising: fastening, in an irremovable way, the head ( 5 ) and the bottom ( 1 ) to the tubular body ( 4 ) without threading and/or welding procedures, by implementing, at the ends of the tubular body ( 4 ), a controlled plastic deformation extended to a whole thickness of the tubular body to locally deform the first and second ends by generating on each of the first and second ends at least a circumferential ring radially projecting inwards so as to insert in at least a specific groove ( 7 ) arranged, respectively, on the bottom ( 1 ) and on the head ( 5 ) inserted in the tubular body ( 4 ), so as to lock the bottom ( 1 ) and the head ( 5 ) in situ, wherein said plastic deformation guarantees a mechanical seal of a coupling between the tubular body ( 4 ) and the bottom ( 1 ), and between the tubular body ( 4 ) and the head ( 5 ), wherein said controlled plastic deformation is performed by means of mechanical rolling upon said tubular body, said tubular body being free to rotate about a central, longitudinal axis through said tubular body, wherein the mechanical rolling is performed by anchoring the tubular body, preassembled with the head and the bottom, to at least a special multiroller head comprising a plurality of shaping rollers (R 1 ) configured to plastically deform the tubular body, and wherein the rollers (R 1 ) move symmetrically in a radial direction with respect to the tubular body ( 4 ), and each of the rollers have a same simultaneous rotating motion to rotate the tubular body ( 4 ) about the central longitudinal axis integrally with at least one of the bottom ( 1 ) and the head ( 5 ) positioned inside the tubular body, the movement of the multiroller head upon the tubular body causing the tubular body to plastically deform by means of an adequate pressure of said shaping rollers (R 1 ) upon an outer surface of the tubular body.