| 摘要 |
<p>The external driving mirror is set at the selected angles by a servo driven shaft (2) from an electric motor. The shaft is coupled to the mirror by a special threaded nut (4). The nut is moulded from a thermoplastic and has axial slots (6) extending from either end. This provides a weakened structure so that when the torque on the drive shaft exceeds a set value the nut is splayed out to disengage the threads, and allow the drive to slip. Alternatively, only the top and bottom edges of the nut are threaded leaving the middle section clear of the thread.</p> |
