Dish washing machine with improved wash mechanism

Abstract

An automatic domestic dish washing machine has a chamber for the items to be washed and a pump to pressurize the washing fluid. A spray arm includes elongated top and bottom walls encompassing an elongated passageway to receive the pressurized fluid. A spray device has an elongated body with a passageway and an exit opening at each end of the passageway. A hollow support shaft extends perpendicular to the body and includes a passageway communicating with the body passageway. The shaft is mounted in the spray arm with lateral openings in the shaft communicating with the passageway in the arm so that fluid flows through the arm, shaft and body and sprays out through the exit openings. The lower portion of the shaft is cylindrical and extends through an opening in the bottom wall of the arm. A bearing mounted to the arm includes a longitudinal opening surrounding the lower portion of the shaft and spaced from it to define an annulus with a width just greater than the size of hard waste particles likely to be entrained in the wash fluid. A thrust washer is attached to the shaft below the bearing. When pressurized fluid flows through the spray device the shaft lifts and the washer engages the bearing and centers the shaft in the longitudinal opening. When pressurized fluid is not flowing, the shaft lowers and the thrust washer is spaced below the bearing a distance greater than the width of the annulus between the bearing and the shaft.