| 摘要 |
A fence is provided with a rail or stringer 20 being attached to a post 1 to support a panel 2 between each post 1. The rail or stringer 20 has a recess containing a sensor cable 40, together with a plurality of retaining elements (60,fig.7) which can be individually positioned in order to retain the sensor cable 40 in the recess. In a further aspect, brackets 10 are provided having a front wall (14,fig.4), and upper and lower walls 15,16 which enclose the ends of the rail 20 so as to prevent access to the cable 40 other than from the rear of the fence. The rail 20 may be angularly adjustable with respect to the brackets 10, such that the fence can be installed on sloping ground without exposing the cable 40 at the ends of the rails 20. The retaining means (60,fig.7) ensure that the cable 40 remains in contact with the rail 20 along substantially all of the length of the rail 20 so as to transfer vibrational energy more effectively from the fence to the cable 40. The arrangement is particularly suited to sensing unauthorized activity at the fence such as an intruder attempting to climb or cut the fence. |
