Device for indicating when automatic, periodic operation has emptied an aerosol container

摘要

A device incorporated in an apparatus for automatically and periodically operating an aerosol container indicates when the container has been emptied and then stops operation of the container. The container operating apparatus includes a motor operatively linked to the container and a power supply for powering the motor. The stopping and indicating device comprises a timing circuit that includes a first time measuring network that produces motor actuating output pulses at a first periodic rate, each actuating pulse being of duration sufficient to cause the motor to operate the container. The timing circuit also includes a second time measuring network that produces non-actuating output pulses at a second periodic rate substantially greater than the first rate, each non-actuating pulse being of duration insufficient to cause the motor to operate the container. A switch selectively operates the motor through either the first or the second time measuring network and a sensor, which determines when the container has been emptied, actuates the switch to operate the motor through the second time measuring network.