Spring-loaded automatic fluid-dispensing system

摘要

An automatic soap dispenser (10) includes a bellows-type collapsible container (18) of liquid soap. Constant-force springs (40 and 42) compress the container so as to expel the soap through a spout (16) when a valve-containing dispensing mechanism (20) permits it. When a sensor (14) detects an object such as a user's hand, a control circuit (56) operates the dispensing mechanism to permit soap flow through the spout for a predetermined time interval. Because of the constant-force springs, there is no need to use electric power to eject the liquid soap despite its typically high viscosity.