| 摘要 |
A switch (22) controlled by the withdrawable screen (15), switches the electric motor (13) on and off. A control device is provided for the stepless control of the motor r.p.m. according to the position of the screen. The control device (24) is a slide resistance. A follower is arranged at the rear edge of the screen (15). which, upon withdrawal of the screen, works in conjunction with the slider (25) of the resistance. The slider resistance is spring loaded to hold it in its rear end position. USE/ADVANTAGE - Fume exhaust hook. Gives improved control and is simpler to operate. |
