| 摘要 |
<p>1473187 Selective printing PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 24 May 1974 [30 May 1973] 23348/74 Heading B6F A recording element for a matrix printer includes a stylus 13 attached to armature 9 driven against a restoring spring 27 by energizing coil 17. The element is characterized by the construction of the spring 27 which has closely wound turns at its ends 37, 39 and relatively spaced intermediate turns 41, the turns 41 being of a diameter to be clear of the stylus 13 and the wall of bore 15. As shown the ends 37, 39 are wound to a diameter providing a loose fit in the bore 15 and on the stylus 13 respectively. Thus the spring 29 does not buckle and chafe on the stylus and bore when compressed. The turns 41 may be of equal diameter or tapered down from end 37 to end 39. Cylinder 3, bushing 5 and armature 9 may be of chromium steel, stylus 13 of tungsten and anvil 7 of glass reinforced nylon with a rubber pad 33. Armature 9 has air passages 31 for dispersal of air in the gap 29 when the armature 9 is moved.</p> |
