Switch mat
AssigneePreh-Werke GmbH & Co. KG
InventorGerhard Hochgesang
Life of this patent
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Abstract
This invention relates to a switch mat with key switches. In previously disclosed switch mats, switch chambers located under dome-shaped key caps were jointly vented. This affected key operation, and allowed soiling by dust and moisture. Here, each switch chamber has a ventilating channel with a filter layer that is permeable to air, for venting to and from the outside. In this design, the filter layer is formed by a filter matting that is dust and moisture-repellent. Because each switch chamber is separately vented to and from the outside, there is no mutual influence on operating forces of the key switches.
Claims3
A switch-mat apparatus comprising a switch mat and a contact sheet, and switch mat apparatus having several key switches with each key switch having a dome-shaped key cap of the switch mat for being pressed toward the contact sheet by a key to complete a contact between a first contact of the contact sheet and a second contact pressed against the first contact by the dome-shaped key cap, with a plurality of key-cap chambers, one under each of the respective key caps, being connected to atmosphere by a ventilating channel, wherein each key-cap chamber has a ventilating channel to atmosphere, said switch mat apparatus further including a fibrous non-woven filter matting layer for each switch chamber that is permeable to air placed over the ventilating channel so that air passing through said ventilating channel must pass through said non-woven fibrous filter matting layer and said contact sheet lying directly on said non-woven fibrous filter matting layer, with the non-woven fibrous filter matting layer consisting essentially of non-coated, non-woven fabric which is dust and moisture-repellent.
Dependencies are inferred from the claim text.