Patent ID: 7508288

Claim:
A magnetic switch arrangement comprising: a first magnetic system ( 24 ); a second magnetic system ( 25 ) disposed in fixed relation to the first magnetic system ( 24 ); and a magnetically responsive switching element ( 18 ) disposed in fixed relation to said first and second magnetic systems ( 24 , 25 ); wherein said first magnetic system ( 24 ) is arranged for biasing the magnetically responsive switching element ( 18 ) into a predefined state and the second magnetic system ( 25 ) is arranged such that its magnetic field interacts with the biasing magnetic field from the first magnetic system ( 24 ) at the magnetically responsive switching element so that the magnetically responsive switching element assumes said predefined state, the arrangement of said first magnetic system ( 24 ), said second magnetic system ( 25 ), and said magnetically responsive switching element ( 18 ) further being such that a change in the spatial distribution of the second magnetic system's magnetic field caused by a ferromagnetic material being brought near or being moved away from said second magnetic system ( 25 ) causes said magnetically responsive switching element ( 18 ) to assume a state other than said predefined state; and wherein said first magnetic system ( 24 ) comprises a magnetic field assembler ( 19 ) arranged for creating a longitudinal magnetic field inside the assembler, the assembler ( 19 ) comprising a thin-walled tube of ferromagnetic material surrounding the magnetically responsive switching element ( 18 ) in close proximity to it.