Patent ID: 8344832

Claim:
A magnetic switch comprising: a first frame; a second frame coupled to the first frame; a stationary contact installed at the first frame to face the second frame; a movable contact configured to make contact with or be separated from the stationary contact; a coil assembly installed at the second frame to face the first frame and having a coil configured to generate a magnetic force according to a flow of an electric current through the coil; a movable unit configured to cause the movable contact make contact with or be separated from the stationary contact while reciprocating through a central portion of the coil assembly, the movable unit comprising a shaft configured to movably support the movable contact in an axial direction and a core coupled to a periphery of the shaft such that the core is movable together with the shaft; a contact spring configured to apply an elastic force to the movable contact in a direction that the movable contact moves toward the stationary contact; a movable distance limiting unit formed at the first frame, the movable distance limiting unit configured to limit a movable distance of the movable unit in order to determine a contact pressure distance for the movable contact to make contact with the stationary contact when the contact spring is pressed; and a return spring configured to apply an elastic force to the movable unit in a direction that the movable contact is separated from the stationary contact, wherein the movable distance limiting unit comprises a guide portion having an accommodation groove configured to accommodate one end portion of the movable unit; wherein a protrusion protrudes from a bottom surface of the accommodation groove toward the movable unit, wherein the shaft comprises a spring support groove configured to guide entry of the protrusion, and wherein the return spring is located between the spring support groove and the protrusion.