Patent ID: 9719900
Date: 2017-08-01
CPC Classifications: G01L,G01N

Claim:
1. A strain-gauged washer for measuring a preload in a bolt, said washer comprising: a washer body having an inner diameter (ID) sized to fit around a shank of the bolt, an outer diameter (OD) based on a size of a head of the bolt, and a thickness which is standard for a flat washer with the ID and the OD, said washer body including one or more slots which are holes drilled completely through the thickness of the washer body and located between the ID and the OD of the washer body; and one or more strain gauges affixed within each of one or more slots in the washer body, where the strain gauges are oriented through the thickness of the washer body to detect compressive strain, and where the strain gauges provide an output signal corresponding to the preload in the bolt when the bolt is tightened.