Method and apparatus for covering a foil strain gauge
AssigneeHottinger Baldwin Measurements, Inc.
InventorWerner Ort
Life of this patent
Estimating the term…
Abstract
A foil strain gauge pick-up is protected against environmental adverse influences by a multi-layer covering hermetically sealing and enclosing substantially the entire pick-up including its terminals. The covering includes at least two layers, preferably three layers. The first layer adjacent to the foil strain gauge proper is an electrically insulating layer. The outer layer may be a vapor deposited metal or oxide layer. An intermediate layer may be electrically conducting.
Claims15
A method of protecting a foil strain gauge pick-up against environmental influences, comprising the steps of preparing a substrate, boring a hole in said substrate, applying foil strain gauge means including terminals to said substrate, receiving the terminals in said bore hole, applying a waterproof, hermetically sealing multiple layer covering to the foil strain gauge pick-up in such a manner that the foil strain gauge proper, said terminals of the foil strain gauge, and at least a portion of any remaining free surface of said foil strain gauge pick-up substrate on which the foil strain gauge is arranged, are enclosed by said multiple layer covering said step of applying a waterproof hermetically sealing multiple layer comprising coating the foil strain gauge means and at least a portion of any remaining free surface of the substrate with an electrically insulating buffer layer, and depositing a further moisture-proof vapor barrier layer thereover, said method further comprising sealing a moisture barrier insulating feed-through in the substrate bore hole having electrical leads therethrough for electrical coupling to the terminals of the foil strain gauge means thereby providing a vapor barrier electrical coupling.
A foil strain gauge pick-up comprising, substrate means, foil strain gauge means including electrical terminal means operatively secured to said substrate and multiple layer covering means enclosing said foil strain gauge pick-up, said covering means comprising an electrically insulating buffer layer and a moisture-tight oxide layer applied to the buffer layer by vapor deposition.
A foil strain gauge pick-up comprising, substrate means, foil strain gauge means including electrical terminal means operatively secured to said substrate, and multiple layer covering means enclosing said foil strain gauge pick-up, said covering means comprising an inner electrically insulating buffer layer and a galvanically deposited moisture-tight outer cover layer.
A foil strain gauge pick-up comprising, substrate means, foil strain gauge means including electrical terminal means operatively secured to said substrate and multiple layer covering means enclosing said foil strain gauge pick-up, said covering means comprising an electrically insulating buffer layer, and a moisture-tight cover layer of nickel applied to the buffer layer by vapor deposition.
A foil strain gauge pick-up comprising, substrate means, foil strain gauge means including electrical terminal means operatively secured to said substrate and multiple layer covering means enclosing said foil strain gauge pick-up, said covering means comprising an inner electrically insulating buffer layer, an intermediate electrically conducting layer comprising epoxy resin with metal powder embedded in said epoxy resin, and a moisture-tight outer cover layer comprising a metal such as nickel.
A foil strain gauge pick-up comprising, substrate means, foil strain gauge means including electrical terminal means operatively secured to said substrate on one side thereof and multiple layer covering means enclosing said foil strain gauge pick-up, said covering means comprising an inner electrically insulating buffer layer and a moisture-tight outer cover layer, said substrate comprising a bore hole therein beneath said foil strain gauge means, an electrically insulating feed-through means forming a moisture sealing barrier in said bore hole, and first and second leads in said feed-through means in moisture sealing relation, one end of each of said leads being electrically coupled to the electrical terminal means of said foil strain gauge means, the other end of said leads extending through said electrically insulating feed-through means, whereby the electrical coupling to the foil strain gauge means forms a barrier to moisture, thereby effectively sealing the foil strain gauge means.
Dependencies are inferred from the claim text.