Abstract: The present invention relates to fasteners and more specifically to a fastener adapted to visually indicate tension, and method of making thereof.

Abstract: The present invention relates to fasteners and more specifically to a fastener adapted to visually indicate tension, and method of making thereof.

Abstract: A simple and compact fluid pressure indicator comprising a housing having a passage communicating with the pressure to be monitored leading to an interior chamber, a flexible diaphragm sealing and dividing the chamber into two parts, a colored indicator area on one side of the diaphragm, a light transmitting viewing window axially aligned with and parallel to the indicator area, and a sealed flexible envelope of light-absorbing fluid interposed between the indicator area and viewing window. A change in the monitored pressure causes the diaphragm to flex and the indicator area to be displaced, altering the thickness of the absorbing fluid envelope, and therefore the amount of light reflected from the indicator area. Thus a very small change in pressure will result in a dramatic color change displayed in the viewing window, providing a sensitive pressure indication.

Abstract: In an indicator for visually displaying extremely small displacements between two points within a structure, a change of color visible through an indicator window occurs during a preselected portion of a predetermined displacement within the structure. The color change occurs due to an increase in thickness of a light-absorbing fluid in the central area of a clear, flexible indicator means separating a colored portion from the indicator window. Substantially no light-absorbing fluid is permitted to enter the central area until a preselected displacement has occurred since the colored portion is firmly, resiliently biased against the indicator window until that amount of displacement has occurred. Thereafter, light-absorbing fluid is permitted to enter the central area. This device concentrates visual indications of displacements into limited segments of an overall displacement.

Abstract: An inductance-capacitance loop defines a resonant circuit and is arranged in a member subject to stress. Strains resulting from the stress vary the inductance or capacitance of the circuit, and its resonant frequency. A dip meter is used to detect the resonant frequency and thus provides a reading indicative of the stress in the member.

Abstract: An indicator for optically indicating small displacements or changes in displacement of one member relative to another member, comprising a light transmitting member having a faceted light reflective under surface, and an opaque, light absorbing member disposed beneath the light transmitting member, whereby when the two members are separated by a thin film of air, incident light transmitted through the transmitting member is totally internally reflected at the under surface displaying a bright appearance to an observer. When the two members are forced into intimate contact by a displacement to be indicated, the incident light is absorbed by the second member and a dark appearance is presented to an observer.

Abstract: An indicator for optically indicating small displacements or changes in displacement of one member relative to another member, comprising a self-contained container encapsulating a light absorbing indicator fluid, a window in the container for viewing the indicator fluid, an opposite wall portion, and a flexible portion in between the window portion and the wall portion, allowing relative movement therebetween so that an external member, fixed to one of the portions may deform the container and change the thickness of the fluid seen through the window in response to changes in displacement between the first two members.

Abstract: An inductance-capacitance loop defines a resonant circuit and is arranged in a member subject to stress. Strains resulting from the stress vary the inductance or capacitance of the circuit, and its resonant frequency. A dip meter is used to detect the resonant frequency and thus provides a reading indicative of the stress in the member.