US 4,822,241 A · Automatic dishwasher with a pump having a selectively adjustable impeller clearance

Abstract

An automatic dishwasher includes a cabinet enclosing an interior washing chamber with a pump mounted in the cabinet for pumping liquids into and out of the washing chamber. The pump includes a housing having spaced apart walls and a rotatable motor shaft extending into the housing from a first one of the walls. A rotatable impeller is mounted for longitudinal movement along the motor shaft and is keyed to rotate with the motor shaft between the spaced apart walls of the housing. A removable bearing mount that supports a thrust bearing is threaded into the pump housing and, with the thrust bearing, provides an axial stop for limiting the movement of the impeller along the motor shaft. The bearing mount also includes an annular surface disposed near the exposed edges of the blades of the impeller and spaced therefrom by a predetermined, desired clearance or gap. The optimization of the clearance maximizes the efficiency of the pump. This clearance is automatically provided in a final pump assembly step when the bearing mount is threaded into place in engagement with the pump housing.

Claims17

Dependent claims

An automatic dishwasher comprising

an interior washing chamber,
a pump assembly for pumping liquids into and out of said washing chamber,
said pump assembly including a motor having a rotatable motor shaft and a pump having both a pump housing and a rotatable impeller disposed in said housing,
said motor shaft extending into said pump housing and said impeller being disposed along and axially movable along the length of said motor shaft and being configured to be engaged and rotatably driven by said motor shaft, and
wall means removably securely engaging said pump housing at an inlet end of said pump housing for providing a radially outwardly extending wall surface spaced from said impeller to provide a desired amount of clearance therebetween, the amount of said clearance being determined by the engagement of said pump housing and said wall means.

2 more elements

A method of assembling an automatic dishwasher pump of the type including a pump housing having first and second spaced apart walls with an aperture formed through said first wall for receipt of a rotatable motor shaft therethrough and also including an impeller disposed about and axially movable along the length of said motor shaft and configured to be rotated by said motor shaft, comprising the steps of

forming said second wall with an aperture coaxially aligned with said motor shaft and configured to enable said impeller to move thereby along the length of said motor shaft,
positioning said impeller onto said shaft from outside said pump housing,
moving said impeller axially along said shaft such that at least a portion of said impeller passes through said aperture in said second wall,
enclosing an annular portion of said aperture in said second wall by removably securely attaching a removable wall member to said pump and
adjusting the position of said removable wall member axially along the length of said shaft to provide a desired clearance between said removable wall member and said impeller, thereby to provide for the efficient operation of said pump.

2 more elements

Dependencies are inferred from the claim text.

Automatic dishwasher with a pump having a selectively adjustable impeller clearance

Life of this patent

Automatic dishwasher with a pump having a selectively adjustable impeller clearance

Life of this patent

Abstract

Claims17