| 摘要 |
<p>A drive spindle through which a liquid flows under pressure supplied along a first hydraulic circuit (10) defined by an inlet duct (9), a tubular output shaft (3) of the drive spindle rotatingly engaged in the inlet duct (9), and by a tubular tool (5) attached to said output shaft (3), is provided with a second hydraulic circuit (20) to discharge at least the liquid that passes between the inlet duct (9) and the output shaft (3) outside the drive spindle, and has a tubular seal member (12) that is slidingly attached to the output shaft (3) and to the inlet duct (9) so as to move, under the force of the liquid and when the pressure of the liquid exceeds a given maximum value, from an open position to a closed position of the second hydraulic circuit (20).</p> |
