| 摘要 |
PURPOSE:To facilitate working, reduce weight, suppress abrasion and enable to prolong the useful life of a printing hammer, by a method wherein impacting pins are shrink- fitted into pipes while leaving some tip part of the pins on the outside of the pipes, and the pipes with the pins are fixed to tip parts of a leaf spring. CONSTITUTION:Stainless steel pipes 4 having an outside diameter of about 0.97mm. and an inside diameter of about 0.295mm. at normal temperature are heated to about 500 deg.C to enlarge the inside diameter to about 0.30mm., then tungsten wires 3 having a diameter of about 0.295mm. are inserted into the pipes 4, and the temperature is returned to normal temperature, thereby shrink fitting the pipes 4 and the wires 3 to each other. The pipes 4 with the wires 3 fitted therein are fixed into fitting holes of the leaf spring 1 by laser welding, brazing or the like. Accordingly, the dimensional accuracy of the pins 3 and the pipes 4 can be easily secured by drawing without machining, the length thereof can be determined by simply cutting collectively a multiplicity of the pins 3 or the pipes 4, and the accuracy in fitting the pipes 4 to the leaf spring 1 is enhanced. In addition, the weight of tip parts of the pins 3 is reduced, abrasion of a yoke and the leaf spring at the time of an impact for printing is lessened, and noise is reduced. |
