| 摘要 |
<p>The sensor head assembly (12) with windows in one side to receive light from a luminous source contains the electronic circuit to process the received signals. The base of the head has a peripheral ear (28) which engages a corresponding groove (24a,b) in the top of a base assembly (14) and in the cover (16). This groove is below a ring (26a,b) which traps the car when a cheek (30) on the cover engages the base. The head can be orientated as required when the cover and base are separated and then locked into position when the cover is fastened to the base by screws. A cavity in the base of the head permits mounting of a connector block on a spigot (40). This ensures that any electrical connections can be made.</p> |
