Dual water-level toilet flushing apparatus

A dual water-level toilet flushing apparatus that selectively operates in either a normal, preset partial flush or a full flush and that is designed to be installed in a toilet tank and to function in combination with a toilet tank drain, a toilet flush handle that is operated by a chain and flush arm, a flapper valve and an overflow tube, said apparatus comprising:

• a) an overflow tube sleeve having means for being held in place around the overflow tube and having near its upper section on each side, a laterally extending pivot pin,
• b) a pendulum/flapper valve link having a longitudinal pendulum slot in its upper section and a lower end having means for pivotally being attached to a front mounting tab on the flapper valve, where the back of the flapper valve has a pair of back mounting tabs that are swivelly attached to a pair of flapper valve hooks attached near the bottom section of the overflow tube,
• c) a floatable inverted pendulum comprising:
• (1) a lateral support member having at its front end a clevis that engages and traverses the pendulum slot on said pendulum/flapper valve link, s
• (2) a first side support member attached to an outer side of said lateral support member and having a pivot pin bore located at its back section that is pivotally mounted over the respective pendulum pivot pin on said overflow tube sleeve, and further having a flush chain bore to where the chain that is operated by the flush handle via the chain and flush arm is attached,
• (3) a second side support member attached to the other side of said lateral support member and having a pivot pin bore located at its back section that is pivotally mounted over the respective pendulum pivot pin on said overflow tube sleeve, and
• (4) a cavity support structure attached to an outer side of said second side support member, said structure having at least one upper cavity and at least one lower cavity of less volume, where said cavity support structure controls the net torque caused by the force of its buoyancy and the opposite applied force of gravity about its point of attachment to said sleeve, where these forces then allow said pendulum to control the timing of the opening and closing of the flapper valve, and wherein the flushing is accomplished by performing the following steps:
• a) partial flush--press and immediately release the flush handle;
• when the handle is depressed, the chain via the flush arm pulls upwardly on the floatable inverted pendulum, causing the pendulum to rotate to a maximum counterclockwise position and causing the flapper valve to rotate CCW to a fully open position at which time the water level begins to drop and flow out the toilet tank drain, upon releasing the toilet flush handle, the chain force is released clockwise (CW) to a substantially vertical position, the pin moves to the bottom end of the pendulum slot on the pendulum/flapper valve link and the center of gravity of said pendulum shifts to the right and when the water drops to a level below said pendulum, said pendulum loses its buoyancy and the force of gravity of said pendulum and the water remaining in the at least one upper cavity of said pendulum rotates to cause said slotted link to push on and fully rotate the flapper valve CW to its closed position to stop the flow of water through the toilet tank drain,
• b) full flush--press and hold down the flush handle for several seconds;
• during the time the handle is depressed, the chain via the flush arm pulls upwardly on said inverted pendulum causing said pendulum to rotate to its maximum CCW position, and the flapper valve to rotate CCW to its fully open position at which time the water level begins to drop and flow out the toilet tank drain, by the time the flush handle is released, the water level will have dropped to a level below said pendulum but said pendulum remains in its furthest CCW position because the center of the force of gravity is on the left side of the overflow tube, when the water drops further to a level below the flapper valve, the valve loses its buoyancy and commences to rotate CW, at this same time, by means of said pendulum/flapper valve link, the valve causes said pendulum to move CW and drop by the force of gravity to further aide in the closure and seating of the flapper valve on the toilet tank drain to stop the flow of water.