A pressure operated electrical switch and an alarm system for use in hospitals and nursing homes is constructed such that a force is applied to the upper surface of a leaf spring therein. Once the load is reduced below a predetermined value the leaf spring will move to close/open a microswitch or electrical...http://www.google.fr/patents/US4378476?utm_source=gb-gplus-shareBrevet US4378476 - Pressure operated electric switch and alarm system using such switch
Pressure operated electric switch and alarm system using such switch
