Patent ID: 8031038

Claim:
A magnetic fixing device comprising a clamping plate having a fixing surface for fixing a clamping object such as a mold and plural magnetic force generation mechanisms installed in the clamping plate for fixing the clamping object to the fixing surface by magnetic force, wherein each of said magnetic force generation mechanisms comprises a magnetic material member facing said fixing surface, plural permanent magnets arranged around an outer periphery of said magnetic material member, a first Alnico magnet provided on a back of said magnetic material member, and a first coil for switching a polarity of said first Alnico magnet, and can be switched between an absorption state in which the clamping object is adsorbed and a non-absorption state in which the clamping object is not adsorbed, an operation state indication mechanism capable of presenting an indicator indicating that said plural magnetic force generation mechanisms are in the adsorption state or in the non-adsorption state is provided on the fixing surface or outer periphery of said clamping plate and comprises a second Alnico magnet, a second coil electrically connected to said first coil in parallel wound around said second Alnico magnet, and a movable indication member made from a permanent magnet, and an energizing circuit that energizes said second coil only while said first coils of said plural magnetic force generation mechanisms are energized is provided.