Axial acceleration sensor

Claim 1

A sensor for detection of axial accelerations in an internal combustion engine, comprising: a case having a base including means for fastening said case to a source of said axial accelerations; a piezoelectric element in said case and having an aperture; a seismic mass in said case and having an aperture; a headed cylindrical element fixed to said base, said cylindrical element passing through said apertures of said piezoelectric element and said seismic mass with said piezoelectric element being positioned on said cylindrical element between said base and said seismic mass; spring means mounted on said cylindrical element and pressing on said seismic mass for biasing said piezoelectric element between said base and said seismic mass; electrical output means mounted on said case; and flexible electrical connection means comprising: (a) an elongate strip of flexible insulating material having a flat face, (b) two annular conductive layers on said flat face, (c) apertures through said insulating material at centers of said annular conductive layers, said insulating material being folded at a position between said conductive layers and said insulating material being mounted on said cylindrical member with said cylindrical member passing through said apertures thereof and said annular conductive layers each engaging an opposite side of said piezoelectric element, (d) two conductive terminal layers on said flat face at positions spaced from said annular conductive layers and each terminal layer connected to said electrical output means, and (e) conductive connecting layers on said flat face and each said connecting layer connecting one of said annular conductive layers with one of said terminal layers.