Membrane switch venting arrangement for washing appliance

Details Membrane switch venting arrangement for washing appliance Membrane switch venting arrangement for washing appliance

2002-07-02

2003-08-26

Friedhofer, Michael (Department: 2832)

Electricity: circuit makers and breakers

Electric switch details

Cases and bases

C200S515000

Reexamination Certificate

active

06610943

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to the art of appliances and, more particularly, to a venting arrangement for a membrane switch employed in a domestic washing appliance.
2. Discussion of the Prior Art
When utilizing a switch, particularly a switch including a pair of closely spaced electrical contacts, a foreign material can undesirably become interposed between the contacts to inadvertently complete a circuit incorporating the contacts. In addition, or in the alternative, the foreign material may be corrosive.
Membrane-type switches can be particularly problematic in this regard. That is, based on the specific construction of the membrane switch, it may be necessary to vent the switch contacts to atmosphere. In general, this venting can be necessary to facilitate the operation of the switch over broad atmospheric and temperature extremes. Developed problems in this field can be exasperated when the environment surrounding the membrane switch is hostile to the switch due to the presence of excessive humidity, liquid, and the like. In extreme environments, switch contacts and circuitry are typically sealed to protect against damage.
Based on the above, there exists a need for an improved venting arrangement for a membrane switch which will enable the switch to be effectively used in the moisture-laden environment of certain domestic appliances, particularly dishwashers and clothes washing machines. That is, there exists a need to configure a venting arrangement for a membrane switch incorporated into a domestic appliance so as to prevent undesirable contamination of internal components of the switch.
SUMMARY OF THE INVENTION
The present invention is directed to the venting of a membrane switch incorporated in a domestic washing appliance in a manner which assures that the membrane switch can be effectively used in a moisture-laden environment. In accordance with the invention, the venting for the membrane switch includes an elaborate venting passage composed of a long, small diameter, twisting channel that provides a cost efficient and effective barrier to fluids and other moisture, while accommodating the free passage of gases. In the most preferred form, a labyrinth venting arrangement is formed by cutting a channel into a supporting plastic assembly and then adhesive bonding the switch over the labyrinth feature to complete the passage. One end of the passage is open to atmosphere by way of a slot in the supporting plastic assembly, while the other end joins the venting path with the membrane switch.
By employing the labyrinth venting arrangement, a membrane switch can be effectively incorporated in domestic appliances which, due to their functions, are inherently subjected to high humidity conditions. In any case, additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.


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