Abstract: A permanent magnet with a split magnetic flux conductor between the pole shoes serves to attract a magnetizable load to the pole shoes of an electromagnet whose pole shoes constitute extensions of the pole shoes of the permanent magnet and whose split magnetic flux conductor extends between the respective pole shoes in parallel with the other conductor. An armature is movable into the gap between the parts of the magnetic flux conductor of the permanent magnet or between the parts of the magnetic conductor of the electromagnet by a fluid-operated motor or by the application of d-c current of proper polarity to the exciting coils of the electromagnet. The permanent magnet ceases to attract the load to the pole shoes of the electromagnet when the armature is moved into the gap between the portions of the magnetic flux conductor of the electromagnet.

Abstract: A single or composite lifting electromagnet has several cores whose poles can attract round, elongated or otherwise configurated ferromagnetic objects. The cores are surrounded by and/or flank discrete sensors in the form of Hall generators or induction coils which are provided in addition to exciting coils for the cores. The sensors are disposed centrally of or mirror symmetrically around the center of the electromagnet, and the purpose of the sensors is to generate signals in response to changes of the electromagnetic field to thereby facilitate automatic guidance of the electromagnet toward an optimum position with reference to an object which is to be lifted and transported, e.g., to the treating station of a machine tool.

Abstract: A lifting electromagnet for ferromagnetic workpieces has two composite cores which extend downwardly from a yoke. Each core has a first section which is rigid with the yoke and is surrounded by an exciting coil, a second section which is connected with the respective first section, and at least one third section which is movable with reference to the second section, either up or down or horizontally. The poles at the lower ends of the third sections make an angle of 120 degrees, the same as the poles at the lower ends of the second sections. The second sections are surrounded by induction coils, and a further induction coil is disposed between each pair of neighboring third sections. The distance between the second sections is less than the distance between the first sections, and the distance between the second sections exceeds the distance between each pair of third sections.