Drain trap valve mechanism

Claim 1

A float actuated valve mechanism for controlling the level of liquid in a sump area comprising: a fluid conduit communicating with said sump area; a valve seat means fixed to one end of said fluid conduit; a valve plug movable against said valve seat to close and open said one end of said fluid conduit; a linkage base fixed relative to said conduit and providing two linkage base pin joints; a float arm having one end attached to one of said linkage base pin joints, said float arm being pivotal about said linkage base pin joint to which said float arm is attached; a float within said sump area connected to the other end of said float arm; a valve plug arm having one end attached to the other of said linkage base pin joints, said valve plug arm being pivoted about said linkage base pin joints to which said valve plug arm is attached, said valve plug being mounted on said valve plug arm; a float arm pin joint provided by said float arm; a valve plug arm pin joint provided by said valve plug arm; and a connecting arm means extending between and pivotal about said float arm pin joint and said valve plug arm pin joint, said linkage base and said arms constituting a fourbar linkage providing a non-linearly varying mechanical advantage between said float and said valve plug, said arms, said float and said valve plug being movable in a generally common plane.