| 摘要 |
<p>A pneumatic spring such as is used to assist the opening and closing of vehicle bonnets includes a conducting tongue 6 attached to the piston 3 and ring 7 at the bottom of the cylinder. In the extended position, the tongue 6 contacts the cylinder 1 and a circuit is established between terminals 8 and 9, while in the contracted position, the ring (if insulating) interrupts the connection between tongue and cylinder. In an alternative embodiment, the tongue does not extend as far as the cylinder wall but does make contact with the ring, being of smaller internal diameter. In this case, the ring is conductive and completes the connection when the spring is contracted. The device can switch on, for example, the internal light of a car bonnet. <IMAGE></p> |
