Electromagnetic bell unit, its fitting structure and a method of welding the bell and the yoke of the unit

摘要

A miniaturized electromagnetic bell unit suitable for use with an alarm clock and the like is provided. The bell unit of the present invention is characterized in that it is miniaturized in such a way that a yoke to which a coil and a bell hammer are attached is incorporated within a bell and the bell is fixed to the yoke. Besides the simplicity of its structure, the advantages of the present invention are that the bell hammer can be adjusted in a simple manner through a hole drilled in the bottom of the bell; both the bell and the yoke are held fixed together simply and firmly such that a positioner is inserted into holes drilled correspondingly through the bell and the yoke while at the same time, an arm integrally extending from the yoke is fixed to a fixing member; and further, another hole is drilled in the bottom of the bell and one of two electrodes is inserted into the bell through the hole while the other electrode is brought into contact with the outer surface of the bell whereby the yoke and the bell are spot-welded to each other simply and securely.