US Patent 6993873 Building curtain wall mullion and sill assembly

Disclosed is a curtain wall assembly used for building exteriors. The curtain wall system includes a first vertical mullion operable to attach to a first sill member and a second vertical mullion operable to interlock with the first vertical mullion. A mullion cap may be attached to a bottom surface of at least one of the vertical mullions. The mullion cap includes a substantially planar bottom plate having an upper surface, a lower surface, a front edge, and a back edge. The mullion cap further includes an attachment face located on the upper surface of the substantially planar bottom plate. The attachment face is operable to attach to the vertical mullion.