PURPOSE: To make the quick damping of the vibration of an armature possible, by forming a stopper by burying a great number of heavy metal particles into the soft materials of rubber or the like.
CONSTITUTION: The stopper 15 abutting against the inner end of an armature 5 is made of soft materials 16 by rubber into which a great number of heavy metal particles 17 are buried. The heavy metal particles 17 are, for example, lead, iron, tungsten, etc. of large specific gravity and the weight of each particle is 0.05W0.2mg. In such a constitution, when the armature 5 abuts against the stopper 15, each heavy metal particle 17 locally compresses the soft materials 16 and is again displaced in the direction of the armature 5 by receiving its reaction force. However, because the mass of each heavy metal particle 17 is small, the armature 5 receives its reaction force dispersedly from respective heavy metal particles without receiving the concentrated reaction force at one time. Therefore, the vibration of armature 5 and needle 12 is quickly absorbed.
HORII MASAMI
IINUMA MASAYUKI
