| 摘要 |
A magnetic fastener has a fastening element and an attracted element. The fastening element has a permanent magnet with a hole substantially parallel to the direction of the magnetic poles and a ferromagnetic plate on one side of the magnet facing the hole. The attracted element also has a ferromagnetic plate adapted for connecting to the open side side of the magnet facing the hole. Either one or both of the first and second plate can have a ferromagnetic rod that extends into the magnet hole. If only one rod is formed, the length of it extends substantially the depth of the magnet so that when the attracted element is connected to the fastening element, the end of the rod is near or contacting the opposing ferromagnetic plate through the magnet hole. If a rod is formed on each plate, the combined length of the rods is such that the ends thereof are near or touching within the magnet hole when the attracted element is fully engaged to the fastening element. In any event, at least one of the rods has a blind hole extending from the respective plate toward the respective end of the rod. The blind hole cross-sectional area is at least 2.2% but no more than 88.9% that of the rod.
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