Concealed fastener clip for building panels

Claim 1

A building construction including a support frame, a plurality of panels disposed in edge-to-edge relationship, each panel comprising an outer metal skin, an inner metal skin and an intermediate insulating core substantially filling the space between said outer and inner metal skins and joined thereto, one edge of each said panel having a recessed groove of generally U-shaped cross section, the end portions of said outer and inner metal skins at the edge of each said panel being bent and offset inwardly and engaging an edge portion of said insulating core to form a female member, said recesses groove being formed by said insulating core and said end portions of said outer and inner metal skins, each said outer and inner metal skin end portions having a return element bent and offset inwardly in parallel spaced relation to its respective skin and engaging an edge portion of said insulating core, and the other edge of said panel having an edge portion of reduced thickness, the end portion of said outer and inner metal skins at the other edge of each said panel being bent and offset inwardly and engaging an edge portion of said insulating body to form a male member, said panels being joined in edge-to-edge relationship with the male member of one panel being received by the female member of an adjacent panel to form interlocking and telescoping joins therebetween, at least one concealed fastener clip to secure adjacent panels to said support frame comprising a central portion of generally C-shaped cross section which generally follows the annular space between said male and female members of engaged panels, said central portion having leading and trailing edge portions of circular cross section and a constant radius, said trailing edge of said central portion having a standoff leg terminating in a lateral flange, each said central portion being sandwiched in between said male and female members of adjacent ones of said panels, the entire leading edge of said clip being sharpened in order to cut its own circular path into said insulating core at said female member edge of said panel between said outer metal skin and said outer metal skin return element, whereby the leading edge of said clip is anchored behind said outer metal skin return element, and fastening means to secure said lateral flange of said clip to said support frame, whereby when said panels are in lateral engagement they are secured to said support frame, the male member of one panel being held to the female member of an adjacent panel and the female member of the adjacent panel being held by said central portion of said clip, said concealed fastener clip being hidden from the outside of said construction by the panels as well as from the inside by the supporting frame.