Ball valve lock plate

A three-position ball valve assembly comprising a ball valve and a lock plate assembly,

• said ball valve comprising a body, a valve element disposed for rotation within said body, and a handle mounted for rotation upon said body for operation of said valve element, said handle being movable among a first (off) position, a second (test) position and a third (drain) position, and
• said lock plate assembly comprising a lock plate frame defining a first frame stop for said handle in said first position, a slide latch defining a latch stop for said handle in said second position, said slide latch being mounted upon said frame for movement between a first latch position with said latch stop disposed in the path of the handle in a manner to prevent movement of said handle from said second position toward said third position, and a second latch position with said latch stop removed from the path of said handle to permit movement of said handle from said second position to said third position, said handle, when moving from said third position toward said second position, adapted to urge said latch stop toward said second latch position to permit said handle to move from said third position toward said second position, said latch stop in said first latch position and in said second latch position being adapted to permit movement of said handle from said third position toward said second position,
• said lock plate frame further defining a second frame stop for said handle in said third position, said first frame stop being adapted to prevent movement of said handle beyond said first position and said second frame stop being adapted to prevent movement of said handle beyond said third position, and
• means for biasing said slide latch toward said first latch position.