Knobbe, Martens, Olson & Bear
Foot-operated valve
 A foot-operated valve includes a valve set with a hollow seat and a push rod that extends movably and slidably into the hollow seat and that has a bottom end with a plug provided therearound. The push rod is biased so that the plug blocks normally a distal bottom end of a tubular sleeve that is secured in the hollow seat. When downward pressure is applied on the push rod, the plug ceases to block the bottom end of the tubular sleeve to permit communication between outlet and inlet pipe connectors of the hollow seat. A retaining plate is biased by an extension spring so as to engage the push rod when the push rod moves downwardly, thereby maintaining communication between the outlet and inlet pipe connectors even when the downward pressure applied on the push rod is extinguished. A switch assembly is operable selectively so as to pull the retaining plate away from the push rod to permit the push rod to move upwardly and enable the plug to once more block the bottom end of the tubular sleeve to block communication between the outlet and inlet pipe connectors. 
F
F16K
inventional
Fang-Hsiung Wen-Bin
Chang Wang