1. Field of the Invention
The present invention generally relates to dispensers and, more particularly, to dishwasher detergent dispensers.
2. Description of the Related Art
In the past, it has been common to mount a detergent dispenser to a dishwasher access door. The detergent dispenser employs a dispenser door having a central shaft which extends through the inner panel of the dishwasher door, a stationary actuating member, and a rotary cam and latch member. Typically, the stationary actuating member includes means to release the rotary cam and latch member, which is spring biased by a rotary biasing spring, at a predetermined time in the wash cycle.
Conventionally, the dispenser shaft has a transverse hole into which is frictionally inserted a mounting pin. In the known detergent dispensers, the mounting pin is frictionally inserted to insure its retention within the transverse hole. This frictional fit is provided by closely matching the diameter of the mounting pin at a location along its length with the diameter of the transverse hole. Preferably, the diameter of the mounting pin is identical to that of the hole at this location, or slightly greater than that of the hole, to insure a tight or tension fit between the pin and the dispenser shaft.
Although the aforementioned design may work satisfactorily with some detergent dispensers, it has been found that when the dispenser door and shaft are made of certain materials, such as polypropylene, the door and shaft have a tendency to warp when subjected to the heat produced by the dishwashing machine and prematurely release detergent. If the temperature sensitive material is replaced by more temperature stable materials such as a polycarbonate alloy, the frictional or press-fit of the mounting pin and the dispenser door shaft creates hoop stress in the shaft which, in combination with the harsh environmental conditions encountered in the dishwashing machine, causes the shaft to fracture or break, and renders the detergent dispenser inoperable.
USPTO Backgrounds
USPTO Backgrounds