Dual flush mechanism

Claim 1

A dual flush mechanism, to provide a full-flush and a partial-flush capability for toilets with a tank, in combination with a single flush valve, which dual flush mechanism comprises: a. a flush valve actuating arm, having a first end and a second end, attached near or at its second end to the flush valve by means of a flexible connecting member; b. a first handle control means, to which the first end of the flush valve actuating arm is attached; c. wherein the combination of first handle control means, flush valve actuating arm, flexible connecting member, and flush valve comprise the full flush capability; d. a partial-flush control arm, having a first end and a second end, the partial-flush control arm extending essentially parallel to, and beneath, the flush valve actuating arm; e. a second handle control means, to which the first end of the partial flush control arm is attached; f. means for limiting upward rotational movement of the second end of the partial-flush control arm due to operation of the second handle control means, thereby also limiting resulting upwards rotational movement of the second end of the flush valve actuating arm due to the upward movement of the second end of the partial-flush control arm located beneath the flush valve actuating arm; g. a partial-flush control plate, attached to said partial-flush control arm; h. a partial-flush control lever, having a first end and a second end, pivotally supported interim said first and second ends at a pivot axis; i. a partial-flush float, attached by a flexible connecting member to said first end of said partial-flush control lever; j. a partial-flush counterweight attached to said second end of said partial-flush control lever; k. a pinion gear attached to said partial-flush control lever at the location of pivotal support of the partial-flush control lever so as to rotate about said pivot axis; l. a rack, toothed to gear with said pinion gear; m. a rack extension attached to or formed as part of said rack so as to provide for engagement with said control plate; n. wherein movement of the second handle control means will pivot the second end of the partial-flush control arm upwards, to the extent permitted by the upward movement limiting means, thereby lifting the second end of the flush valve actuating arm a limited distance, and, through the flexible connecting member, lifting the flush valve a limited distance to permit egress of water from the tank; subsequent release of the second handle control means permitting the partial-flush control arm to rotate downwards until the lower edge of the control plate rests against the transversely extending rack extension, thereby also limiting the downward movement of the flush valve actuating lever and keeping the flush valve in a partially open position with associated continuing water egress; said water egress lowering the position of the partial-flush float, thereby pulling the first end of the partial-flush control lever downwards and rotating the partial-flush control lever about its pivot axis; thereby rotating said pinion gear about the pivot axis, the pinion gear rotation causing the rack, and the associated rack extension, to retract out from beneath the partial-flush control plate, said retraction freeing restraint on the partial-flush control arm, allowing further downward movement of the partial-flush control arm, with a corresponding downward movement of the flush valve actuating arm and the reseating of the flush valve to as to terminate the egress of water from the tank; with refilling water raising the water level of the tank, the partial-flush float correspondingly rising, the first end of the partial-flush control lever, assisted by the counterweight at its second end, being lifted so as move the lever about its pivot axis and so rotate the pinion gear so as to cause the rack, and the rack extension, to move outwards until in pressured engagement against the side of the partial-flush control plate of the partial flush control arm, thereby terminating the partial flush cycle by the dual flush mechanism.