| 摘要 |
A vent arrangement is provided for enclosures that prevents the entry of water into the enclosure and that also prevents the penetration of a pry bar or probe wire. The vent arrangement includes a first predetermined pattern of openings of predetermined shape and dimensions provided at the exterior wall of the enclosure. The dimensions of the openings and the spacing between the openings are determined relative to the pry bar and the material in which openings are formed, such that the pry bar cannot fully enter the openings and such that the portion of the pry bar that can be applied to the openings does not cause any substantial deformation of the material surrounding the openings that could permit widening of the openings so as to allow full entry of the tip of the pry bar. In a preferred embodiment, to permit the maximum percentage area of openings within the pattern of openings while achieving the desired tamper-resistant characteristics, the first predetermined pattern of openings include staggered rows of openings such that the openings of adjacent rows are not aligned. The vent arrangement also includes a baffle plate spaced behind the predetermined pattern of openings. The baffle plate includes facilities to freely pass air, but prevents the ingress of any water than may enter through the first predetermined pattern of openings. The baffle plate is arranged to direct all such water out through the bottom of the first predetermined pattern of openings. In a preferred arrangement, the vent arrangement also includes facilities to prevent the ingress of a probe wire beyond the baffle plate and into the enclosure even if the probe wire passes into the venting arrangement beyond the first predetermined pattern of openings. In a specific embodiment, this is achieved by the provision of a double layer of wire-mesh screen or the like disposed within the vent arrangement between the first predetermined pattern of openings and the baffle plate. The double layer of wire-mesh screen is arranged in a closed path in the shape of a cage or the like.
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