Improvements relating to multi-track heads for electromagnetic recording and reproducing apparatus for the recording and reproduction of either sound or impulse, using magnetic tape

摘要

774,174. Magnetic recording and reproducing heads. BRADLEY, L. C. July 29, 1954 [May 4, 1953], No. 12244/53. Class 40 (2). A multi-track head for electromagnetic sound or impulse recording and reproducing apparatus using a magnetic tape, e.g. of the computor type, comprises an assembly of half-track units C, each formed as a separate entity from an assembly of laminµ 20, each of which has a plurality of accurately disposed locating holes 202, 204, Fig. 7; these holes serve both to align the laminµ on posts 22 in a jig, Fig. 9, preparatory to being formed as a unit and thereafter to locate the assembly of units on aligning posts 30, Fig. 4, the assembly being clamped between end plates 31, 31a, Fig. 1, by screws 32 threaded in the posts 30. Two such stacks A, B are disposed opposite each other and are clamped between coverplates 33 by bolts 36 to form a complete head, beryllium-copper foil 34 being interposed between each pair of pole faces 207 and such head being secured to a base-plate 37 by bolts 38. As shown, each unit comprises four pressed sheet steel laminµ 20 treated for fraze removal and annealed, the inner two are precoated with a synthetic resin cement which is allowed to dry before the laminµ are placed in the jig, plates 24 clamped by bolts 25 and nuts 26 compress the laminµ to an extent determined by blocks 23, and the cement is cured under time and temperature controlled conditions. After removal from the jig a coil 27 is wound directly on to the neck 206 of the unit and is connected to tags 29 secured by eyelets 291 to a strip 28 of synthetic plastic material sprung into recesses 208 formed in the two inner laminµ. On assembly, shims 35, 35a are disposed between each unit and the posts 30 may telescope within the inner end plates 31 to permit aligning adjustment by screws 32.