| 摘要 |
PURPOSE:To provide an electromagnet having an armature of small inertia, capable of responding rapidly and suitable for a wire matrix type printing head by a method wherein an armature is comprised of a magnetic body part and a hollow operating body part, and the boundary between the parts is formed in a special structure. CONSTITUTION:The armature 7 of the electromagnet is composed of the magnetic body part 71 and the hollow operating body part (for projecting a wire) 72, and the connecting surface between the two parts is so specified that it is farther from a fulcrum on the side of an attracting face associated with a core 22 and is closer to the fulcrum on the other side, with the part of the connecting surface between the two sides is a straight line, a broken line or a curved line in cross-sectional shape. It is preferable that the operating body part 72 consists of a hollow pipe of aluminum or the like to reduce the moment of inertia of the part 22. Further, it is preferable to provide holes at the side parts of the hollow pipe for making it lighter in weight. |
