Pool cleaner

A swimming pool cleaner comprising a cleaning head having a passage extending therethrough from an inlet, which in use engages the surface to be cleaned, to an outlet for connection to a flexible suction hose having a flow system comprising a valve within the passage at the upstream end of a rigid-walled chamber forming a section of the passage, the valve having:

• a. a passage therethrough forming a mouth, said mouth having a closure means comprising at least one lip, said lip extending upstream from a pivot axis along said passage and being movable about said pivot axis independently of the walls of said chamber downstream thereof in response to water flow therethrough from an open position of the mouth permitting flow into said section to a closed position of the mouth to close said valve passage to thereby shut off flow into said section and
• b. biasing means with low creep characteristics for urging the lip to the open position, said biasing means imparting an opening force to the lip
• i. throughout the range of movement of the lip between open and close under dynamic flow conditions at the design flow rate that is substantially less than the closing force created by the water flow through the valve mouth urging the lip movement towards closure and substantially greater than the closing force imparted by flow through the mouth during lip travel from full closure to the open position and
• ii. over an initial closure-initiating region beginning from the fully open position an opening force on the lip that is substantially less than the closing force on the lip created by the water flow through the valve mouth under steady flow conditions at the design flow rate.

A swimming pool cleaner comprising a cleaning head having a passage extending therethrough from an inlet, which in use engages the surface to be cleaned, to an outlet for connection to a flexible suction hose having a flow system comprising a valve within the passage at the upstream end of a rigid-walled chamber forming a section of the passage, the valve having:

• a. a passage therethrough forming a mouth, said mouth having a closure means comprising at least one lip, said lip extending upstream from a pivot axis along said passage and being movable about said pivot axis independently of the walls of said chamber downstream thereof in response to water flow therethrough from an open position of the mouth permitting flow into said section to a closed position of the mouth to close said valve passage to thereby shut off flow into said section and
• b. biasing means with low creep characteristics for urging the lip to the open position comprising a low creep resilient lever arm attached to said lip and acting on said lip about said pivot axis, said lever arm being restrained at a position along the lever arm distant from the pivot axis from rotation about said axis, said biasing means imparting an opening force to the lip
• i. throughout the range of movement of the lip between open and close under dynamic flow conditions at the design flow rate that is substantially less than the closing force created by the water flow through the valve mouth urging the lip movement towards closure and substantially greater than the closing force imparted by flow through the mouth during lip travel from full closure to the open position and
• ii. over an initial closure-initiating region beginning from the fully open position an opening force on the lip that is substantially less than the closing force on the lip created by the water flow through the valve mouth under steady flow conditions at the design flow rate.