Abstract: A magnetic conductive coverplate of leakage type that may used in magnetic holding devices covers a holding surface of the magnetic holding device. The leakage type magnetic conductive coverplate is made integrally of a single magnetic conductive material. The leakage type magnetic conductive coverplate can conduct magnetic force of the holding device into a workpiece so as to hold it. Because the leakage type magnetic conductive coverplate is made integrally of a single magnetic conductive material, when there is any change in ambient temperature, no crevice will be produced due to different coefficients of expansion and contraction. Therefore, any coolant used in workpiece machining and any magnetic conductive impurities will not infiltrate into or enter the magnetic holding device to lose the internal insulation, thus effectively protecting the internal structure of the magnetic holding device and remarkably improving durability and service life of the magnetic holding device.

Abstract: A magnetic conductive coverplate of leakage type that may used in magnetic holding devices covers a holding surface of the magnetic holding device. The leakage type magnetic conductive coverplate is made integrally of a single magnetic conductive material. The leakage type magnetic conductive coverplate can conduct magnetic force of the holding device into a workpiece so as to hold it. Because the leakage type magnetic conductive coverplate is made integrally of a single magnetic conductive material, when there is any change in ambient temperature, no crevice will be produced due to different coefficients of expansion and contraction. Therefore, any coolant used in workpiece machining and any magnetic conductive impurities will not infiltrate into or enter the magnetic holding device to lose the internal insulation, thus effectively protecting the internal structure of the magnetic holding device and remarkably improving durability and service life of the magnetic holding device.

Abstract: The invention is directed to a magnetic chuck and a method for producing a magnetic chuck. The magnetic chuck comprises an upper base made of a single piece of magnetic-conductive material and having a top surface, sidewalls extending orthogonally from the top surface, a cavity formed within the upper base with an open end opposite to the top surface and an opposite closed end directed toward the top surface. A plurality of cores extends orthogonally from the top surface and into the cavity, wherein a plurality of permanent magnets is arranged in the cavity. A reversible magnet is arranged between each of the cores and a lower base; and an excitation coil is arranged around the circumference of each reversible magnet. A portion of the cavity between the permanent magnets and the closed end of the cavity is filled with non-magnetic-conductive material.