Joint assembly of horizontally opposed curtain wall units

Claim 1

A joint assembly of two adjacent curtain wall units having respectively a horizontally opposed pair of first and second vertical frame members, comprising: (a) the first and second vertical frame members each having respectively a first and a second vertical recess, said first and second vertical recesses of the first vertical frame member being opposite respectively to the corresponding first and second recesses of the second vertical frame member; (b) an exterior gasket composed of a pair of male and female halves having interfitting edges, each of said male and female gasket halves having a base fitted in said second recess of a respective one of the first and second vertical frame members; (c) an interior gasket having opposite edge portions fitted in the opposite first recesses of said interior parts of the first and second vertical frame members, each of the opposite edge portions of said interior gasket projecting beyond said interfitting edges of said male and female gasket halves in an edgewise direction of the curtain wall units; (d) said male gasket half having along said edge thereof a longitudinal tongue, and said female gasket half having along said edge thereof a longitudinal groove receiving said tongue, one of the opposite edge portions of said interior gasket projecting beyond a distal edge of said tongue of said male gasket half; and (e) the extent to which each said edge portion of said interior gasket projects beyond said interfitting edges of said male and female gasket halves being smaller than half the length of said interior gasket and larger than the length of each said edge portion.