Patent ID: 7886982
Filing Date: 2011-02-15
Classification: D06F,G05D

Abstract:
1. An automatic temperature control for a washing machine providing controlled temperature water to a washing chamber by control of a hot-water valve connected to a hot-water line and a cold-water valve connected to a cold-water line, where outputs of the hot-water valve and cold-water valve are mixed to provide the controlled temperature water, the automatic temperature control comprising: a temperature sensor positionable within the controlled temperature water to provide a water temperature electrical signal indicating a temperature of the controlled temperature water; a first and second electrically controlled solid-state switch communicating with the hot-water valve and cold-water valve respectively; a first and second comparator circuit providing control signals to the first and second electrically controlled solid-state switches and receiving the water temperature electrical signal at a first input of each of the first and second comparator circuits; a printed circuit board providing a multi-pole switch having printed circuit contacts for communicating with a second input of each of the first and second comparator circuits and selectively with a least three different voltage reference sources; a temperature control manipulable by a user to operate the multi-pole switch to move the multi-pole switch among states including: (a) a valve-on state outputting to the comparator a first voltage reference outside an expected range of the water temperature electrical signal to cause a connected comparator to switch its associated valve constantly on; (b) a valve-off state outputting to the comparator a second voltage reference outside the expected range of the water temperature electrical signal to cause a connected comparator to switch its associated valve constantly off; (c) a valve-switched state outputting to the comparator a third voltage reference within the expected range of the water temperature electrical signal to cause a connected comparator to switch its associated valve on and off to control a temperature of the controlled temperature water; whereby high current hot and cold-water valves may be controlled solely by low power switch contact suitable for a printed circuit board.