| 摘要 |
The present invention relates to a switchable magnetic device. Additional aspects of the present invention further relate to various devices including a switchable magnetic device. In one aspect there is described a switchable magnetic device of the kind including a housing, a first permanent magnet, a second permanent magnet, the first and second permanent magnets being mounted within the housing such that the first and second magnets are rotatable relative to each other, between a "fully off" position in which the north and south poles of the first magnet are in substantial alignment with the south and north poles respectively of the second magnet such that the device presents a relatively weak external magnetic field, and a "fully on" position in which the north and south poles of the first magnet are positioned substantially in alignment with the north and south poles respectively of the second magnet such that the device presents a relatively strong external magnetic field, characterised in that biasing means are operatively associated with one or both of the first and second magnets to bias the relative rotation of said magnets toward the fully on position, and wherein placing said device on or in close proximity to a ferromagnetic material causes the first and second magnets to rotate to a relative orientation such that the device presents a relatively strong external magnetic field. The device of the first aspect of the present invention provides a switchable magnetic device that can automatically switch to an "on" position in which the device presents a relative strong external magnetic field when the device is positioned on or in close proximity to a ferromagnetic material. |
