摘要 |
Apparatus for controlling the operation of an articulated loading arm comprises a light source (62) connected by optical fibres (61a - 61n) to a plurality of manually-operable optical switches (Sl - Sn), the switches being connected by optical fibres (64a - 64n) to a plurality of light-operated actuators (63a - 63n). The optical switches can include a rotary multiple position switch having discrete positions or incorporating a variable density filter or a pair of mutually rotatable polarising filters. |