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(11) | EP 1 043 259 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Self-centring expanding shaft |
(57) A composite expanding shaft comprising a pneumatic expanding blocking system of a
bobbin and a pneumechanic centering system is disclosed, wherein the pneumechanic
system comprises at least a movable thrust element (3ai) operated by a fluid under
pressure supplied into an expansion chamber (4), a first passage way (8a) being apt
to connect said expansion chamber (4) to an inflation duct (11) of the pneumatic system,
and comprising further an obstructing means (9a) of said first passage way (8a), jointly
movable with said thrust element (3ai) of the centering system, apt to keep closed
said first passage way (8a) for at least a predetermined portion of the thrust element
stroke. |