Electromechanical bell with adjustable loudness - has spring ensuring vibration at lowest setting

摘要

The bell has a permanent magnet and a drive coil moving a flat armature parallel to the coil's axis. The armature has a hammer attached to it that strikes two hemispherical metal shells to produce sound. The hammer has a control element acted on via a control cam by a setting rod and its position altered. The control element (20) is connected to the hammer (4) via a spring (21). The spring is formed by an arm made by a slot cut into the hammer itself so that spring arm and hammer are one. The advantage of the spring arm lies in its ensuring that vibration always occurs in the quietest setting, i.e. the hammer does not become blocked.