Patent Model - Improvement in Electro-Magnetic Alarms

Maker and role
Thomas Hall (b.1827, d.1880), Patentee
Hall's Electric Railway-Switch and Draw-Bridge Signal Company, Assignee
Production date
Jul 18 1870
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Object detail

Wood, brass, iron
14 1/2 x 4 x 3" (36.8 x 10.2 x 7.6cm)
Hall's patent "relates to an improvement in the devices for operating the hammer of an alarm-bell by the action of an electric current and of spring-power. The invention consists in the application of a system of springs arranged alongside of each other, and acting against a plate arranged on the armature and projecting from the sides of the same." (Patent Number 105,447)
Object number
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