| 摘要 |
1,169,105. Making magnetic heads. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 16 Jan., 1967 [18 Jan., 1966], N. 2253/67. Heading B3A. [Also in Division G5] A mono- or multi-track magnetic head comprising a magnetizable core containing a useful gap, one or more reading windings and an auxiliary winding 4 in which a varying current is passed during operation, is made by providing a row of lead-in holes 11 and auxiliary holes 13 in a magnetic material block by ultrasonic drilling and cutting the block along planes which contain the auxiliary holes so that each boundary surface 17, 18 of the core includes part of the wall of an auxiliary hole. In one embodiment, Fig. 4 (not shown), the auxiliary winding is wound using one lead-in hole. The holes 11, 13 need not extend completely through the core but may be drilled from side 26 and material is then removed from the opposite side of the core so that a U-shape profile is formed and the holes extend through the bridge. The core is then cut along planes 21 up to point 22 and the central cut filled with non-magnetizable material e.g. glass the core is then cut from the face 26 along planes 24 to the point 22 and the central cut filled with non-magnetizable material so that the parts 27, 28 are magnetically separated. A polepiece which contains the useful gap, Fig. 7 (not shown), is then secured to the core to complete the magnetic head. In an alternative embodiment, Fig. 6 (not shown), a block of magnetic material (31) is cemented to a ceramic jig (29) after the drilling and the upper surface ground flat or into a U-shape. The block is then sawn along planes (33) to form separate parts (36) and the gaps filled with a non- magnetizable adhesive, e.g. glass. A suitable polepiece can then be secured to the multi-track core to form the multi-trackhead. |
