| 摘要 |
<p>The drawing board is adjustable for height and angle, and its weight, together with that of all components attached to it, is held in equilibrium by a gas-filled spring between it and the frame. An automatic brake, secured by a pull rod, is released by spring action. The spring (4) releases the brake (3) if the pressure in the gas-filled spring (1, 2) is too low or absent altogether. The spring can be attached between a bolt (5) adjustable for height and by a pin in a groove of a bell-crank lever rocking on the brake. The other end of the lever has a further groove, in which a pin on the pull rod (6) engages.</p> |
