| 摘要 |
A retractable bollard apparatus 100 comprising an embedded outer housing having an open end and a closed end, a ram 201 slideably mounted within the outer housing, means for adjusting the axial position of the ram between a fully retracted and fully extended position 40, and means for applying a voltage between the ram 201 and the outer housing. The ram 201 and the outer housing each comprise electrical connectors positioned on the ram and outer housing such that, when the ram is in the fully retracted and/or the fully extended position, the electrical connectors on the ram and outer housing are electrically connected such that a detectable change in the electrical characteristics of the ram occurs to indicate that the ram is in the fully retracted and/or full extended position. |
