摘要 |
The mat has a plate (6) integrated to a mounted ball (3) with possibility of rotating on a base (1), and another plate that acts on the ball to immobilize in desired position. The latter plate is moved by a rod of a pneumatic jack (7) in order to apply the latter plate on the ball for blocking the ball, where the jack is actuated by a pump (8). The latter plate has a hole with diameter lower than that of the ball. |