| 摘要 |
<p>The locking mechanism for the table top of a drawing board is positioned at the top of a central column (1) which can be moved vertically in a guide (2). on each side of the axis of the central column are at least two diametrically opposite brake shoes (6), which can be pressed against the inner surface of the column. Inside the column is a support (4) on a base plate (5) of the guide (2). The brake shoes (6) are positioned on at least one lever (11,12) which is moved on a hinge point (9,10) on the support. Inside the support is a slide (13) which can be moved by means of a push-bar (14) operated by a pedal (15). The brake shoes can be temporarily lifted for drawing board height adjustment.</p> |
