Magnetic reed sensor suitable for use in ignition timing systems

Claim 1

A magnetic reed sensor ignition timing system for use with an internal combustion engine, said engine having an ignition system for producing cylinder ignition at a rate synchronized with the engine and cylinder cycles of said engine, said ignition timing system comprising, in combination: a magnetic member adapted for fixed mounting to a moving member of said engine to translate said magnetic member through a predetermined cyclic translation path and at a rate which is synchronized with the engine and cylinder cycles of said engine; a housing of non-magnetic material adapted to be fixedly mounted to a support which is disposed in close proximity to said translation path to cause said magnetic member to be in close proximity with said housing during a selected portion of said engine and cylinder cycles; a permanent magnet mounted at one end of said housing, said magnet having first and second end poles defining a gap of given distance therebetween and establishing a magnetic flux path thereacross; a reed of flexible magnetic material fixedly mounted at one of its ends to the other end of said housing, said reed having a portion of its other end disposed between said end poles in said magnetic flux path wherein said reed is maintained in a state of stable equilibrium intermediate said end poles except when said magnetic member is in close proximity to said housing whereupon said magnetic flux path is disturbed causing said reed to be deflected away from said magnetic member and toward one of said end poles; and means for determining the position of said reed relative to said cylinder ignition during said engine and cylinder cycles wherein the coincidence of a predetermined reed position and an event indicative of said cylinder ignition during said engine and cylinder cycles indicates a desired ignition timing.