Abstract: A real-time imaging contact gauge for indicating the distribution of contact pressure over a surface includes a transparent base panel, a pressure-transmitting member at one face of the transparent base panel for receiving the contact pressure to be indicated, a birefringent member sensitive to mechanical pressure located between the pressure-transmitting member and the transparent base panel, a plurality of spaced, parallel electro-luminescent layers carried by the transparent base panel for illuminating the birefringent layer, and a polarizer for polarizing the light transmitted to the birefringent layer to produce optical interference patterns corresponding to the contact presssure distribution applied to the pressure-transmitting member, which patterns are viewable through the opposite face of the transparent base panel.

Abstract: A cushioning device for cushioning the contact load on a foot during gait. The cushioning device includes a tread of curvilinear shock absorbing elements substantially extending along a basic contact trajectory equivalent to the locus of substantially maximum contact stress during foot rolling. Each shock absorbing element has a triangular-shaped cross section having an inclined face oriented toward the contact trajectory such that each of the shock absorbing elements is flexed away from the basic contact trajectory during stance. As a result, the cushioning device deforms along the basic contact trajectory to a greater degree than on the rest of the device area, thereby equalizing the plantar contact stresses and improving the shock absorbing process.

Abstract: A contact gauge utilizable for determining contact pressure conditions between two bodies at their interface including a thin plastic sheet capable of memorizing an induced birefringence and a thin, load transmitting member attached to the sheet for inducing the birefringence therein. A method of employing the contact gauge for determining the contact pressure conditions between the two bodies also forms a part of the present invention.

Abstract: Qualitative as well as quantitative evaluation of bite characteristics is performed by subjecting to bite forces pieces of material which exhibits photoelastic memory and studying the resulting impression with a polariscope. A permanent record can also be obtained.

Abstract: A device for indicating the force applied by a tool comprises a bar arranged so as to be deflected in accordance with the force applied, a pair of spaced stops carried by the bar, a frame enclosing both stops with one end of the frame engaging one side of one stop and the opposite end of the frame extending past the other stop to define a space therebetween, and a load sensing member disposed in the latter space, whereby the deflection of the bar is converted by the two stops and the frame to a compressive force on the load-sensing member. The described load-sensing member is a photoelastic member and the described device in which it is used is a surgical spreader hand tool wherein the photoelastic member indicates to the surgeon the force applied.

Abstract: A method and apparatus are described for indicating or measuring contact pressure distribution over a surface, in which method and apparatus, a pressure-transmitting member having a plurality of point-contact projections is used to transmit the contact pressure, in the form of a plurality of localized points, to a photoelastic member. The photoelastic member is one whose optical properties are changed when the member is subjected to pressure, and the changes in optical properties are optically displayed by directing polarized light onto the photoelastic member to produce interference patterns at the localized points of contact pressure.