Patent GB-1505775-A (GB)
Title: Electromagnetic method of dismantling multiple component units
IPC: H01F7/20
Filed: 1976-05-19
Abstract: 1505775 Electromagnets; magnetic holding devices INST FIZIKI AKAD NAUK LATVII SSR-USSR and SPETSIAL KONSTRUKTOR BJURO MAGNITNOI GIDRODINA INSTFIZIKI AKAD NAUK LATVII SSR 19 May 1976 20699/76 Heading H1P For dismantling a unit comprising plural cylindrical non-magnetic current carrying parts lying along a common axis and interconnected by cooperating projections and recesses (Figs. 1, 2, not shown) the parts are withdrawn axially by placing the unit in an alternating uniform magnetic field wherein the axis is perpendicular to the induction vector of the field. Insulant oxide films between the successive parts enable currents to be induced therein flowing in opposed directions along the conjoining planes of adjacent parts, to set up axial separating forces of repulsion therebetween operating to divide the unit into its several components. To prevent jamming the filed is applied alternately in opposite directions along the conjoining plane to balance the repulsion forces between the upper and lower portions of the unit, while maintaining the total force of repulsion in the same sense. The induction vector of the alternating field may be displaced by 90 degrees and the field may be concentrated near the joining planes and/or intermittently applied to successive joining planes for simultaneous withdrawal. For dismantling a unit comprising, e.g. 5 parts (Fig. 3), two pairs of C-shaped A.C. energized electromagnets 51, 52 are successively arranged on an inclined surface 4 with pole shoes 61, 62 tapered in thickness towards their outer ends to concentrate the field in the area of the junction planes 31, 32, 33, 34. The displacement between the pole shoes 61 of the first pair is slightly less than 3 times the length of one part while that between the poles shoes 62 of the second pair is slightly less than this length. The unit is rolled down the inclined surface into the space between the poles 61 where magnetic fields in joining planes 31' 34 separates parts 11 and Ig. Thereafter the unit moves into the space between poles 62 where parts 12, 14 are separated; the field being applied alternately in different directions along the conjoining planes 31 to 34 by rolling the unit. The magnetic flux may be offset in the direction of withdrawal by profiling the pole shoes. For dismantling a unit comprising (Fig. 4) a base 7 with three projections 81, 82, 83 thereon having cylindrical bosses 91' 92, 93 keyed thereon with an interference fit with axes of symmetry 101, 102, 103. There is provided (Fig. 5) three C-shaped electromagnets 11 symmetrical with regard to the latter axes. Each magnet provides a field whose induction vector is perpendicular to the corresponding axis of the respective boss 91, 92, 93, and is mounted on a bearing 12 for rotation about a corresponding axis 101, 102, 103 whereby the sense of the induction vector of the field may be rotated. The magnets are reciprocable along axes 101, 102, 103 for setting up, and the pole shoes 11 are shaped to concentrate field adjacent the conjoining planes. On energization the frequency and intensity of fields are such as to exceed the forces of cohesion between bosses 91, 92, 93 and projections 81, 82, 83. The frequency is adjustable to vary the depth of penetration of the induced currents.