Patent attributes
A plunger includes a lever, a pipe, a rod passed through an axial hole of the pipe, a covering member, and a spring; the rod will be upwards displaced when the lever is pivoted upwards; the rod has a passage therein, and a head at an upper end for connection with an air pump; the covering member has a neck, and an outlet on a lower side; the pipe is inserted in the neck; two airtight rings are secured on an inner side of the neck; the rod is normally biased to a lowermost position by the spring; the lower end of the rod will block the outlet, and the passage will communicate with inside of the covering member when the rod is in lowermost position; when the lever is pivoted upwards, high-pressure air will escape through the outlet to push a blockage in a drain tube of a sink.
