Abstract: A magnetic assembly includes a cylindrical magnet 1 having opposing magnetic poles disposed at respective first and second faces 2 and 3. A cup-shaped ferrous metal housing 4 forms a magnetic shield around the magnet 1 enclosing the second face 3, with an end face 7 continuously surrounding the first face 2. A ring magnet 8 surrounds the housing 4 with opposing magnetic poles disposed at respective first and second faces 9 and 10 with the first face 9 surrounding the end face 7 of the housing. The ring magnet 8 is enclosed within a further ferrous metal housing 11 forming a magnetic shield around the ring magnet and enclosing the second face 10. The further housing 11 has an end face 14 which continuously surrounds the first face 9 of the ring magnet. The end faces of the housings 4 and 11 are proximate to the respective first faces of the magnet 1 and the ring magnet 8 such that these faces together form a planar magnetically active surface.

Abstract: A magnetic assembly includes a cylindrical magnet 1 having opposing magnetic poles disposed at respective first and second faces 2 and 3. A cup-shaped ferrous metal housing 4 forms a magnetic shield around the magnet 1 enclosing the second face 3, with an end face 7 continuously surrounding the first face 2. A ring magnet 8 surrounds the housing 4 with opposing magnetic poles disposed at respective first and second faces 9 and 10 with the first face 9 surrounding the end face 7 of the housing. The ring magnet 8 is enclosed within a further ferrous metal housing 11 forming a magnetic shield around the ring magnet and enclosing the second face 10. The further housing 11 has an end face 14 which continuously surrounds the first face 9 of the ring magnet. The end faces of the housings 4 and 11 are proximate to the respective first faces of the magnet 1 and the ring magnet 8 such that these faces together form a planar magnetically active surface.