Interlocking mullion construction

Claim 1

In a curtain wall assembly or the like including a plurality of adjacent frame subassemblies, a tubular, interlocking split mullion construction linking adjacent frames, comprising first and second, generally U-shaped, rigid half sections each including first and second legs, locking means for joining the first leg of one said section to the first leg of the other said section, said locking means including a laterally open bearing pocket member on one said first leg, a trunnion member on the other said first leg, said trunnion member being sidewise insertable into said pocket when said sections are in a first angularly related position, said pocket member and said trunnion member including cam and follower means, said cam and follower means being spaced from each other in said first angularly related position, and being positioned to be shifted into engagement when said sections are pivoted from said first toward a second angularly related position, said cam and follower means, in the course of said pivotal movement, having coacting interengaging means for progressively laterally shifting one said section relative to the other said section in a direction normal to the longitudinal axis of said sections responsive to continued pivotal movement of said sections, said second leg portions of said sections including blocking portions adapted to overlap in said second angularly related position, said blocking portions, in said second position, being forced into engagement with each other responsive to said lateral relative movement of said sections, and auxiliary fastening means locking said first and second sections together against relative movement in said second angularly related position.