Sashless window structure of vertical sliding panel type

Claim 1

A SASHLESS WINDOW STRUCTURE COMPRISING A FRAME HAVING A SILL, HEADPIECE, AND JAMBS, AN INNER AND AN OUTER WINDOW EACH COMPRISING A UNITARY PANEL TRACK MEMBER FIXED TO EACH SAID JAMB AND EXTENDING FROM SAID SILL TO SAID HEADPIECE, EACH SAID MEMBER HAVING A BASE SEATED ON SAID JAMB, A FORWARD WALL IN PERPENDICULAR RELATION TO SAID JAMB, AND A REARWARD WALL IN OPPOSED SPACED RELATION TO SAID FORWARD WALL, SAID WALLS HAVING CONFRONTING SURFACES FOR RECEPTION OF GLASS PANELS THEREBETWEEN, EACH SAID REARWARD WALL CONFRONTING SURFACE HAVING A LONGITUDINALLY DISPOSED UNDERCUT GROOVE THEREIN EXTENDING FROM END TO END THEREOF, AN ADAPTER STRIP MOUNTED IN EACH SAID TRACK MEMBER AND HAVING A RIB SEATED IN SAID GROOVE, A LOWER END SURFACE SEATED ON SAID SILL, AND AN UPPER END SURFACE CONSTITUTING AN UPPER GLASS PANEL SEAT EXTENDING FORWARDLY FROM SAID REARWARD WALL, SAID SEATS BEING IN OPPOSED RELATION, THE FORWARD WALL OF ONE OF SAID MEMBERS TERMINATING BETWEEN SAID SEAT AND SAID SILL, A PANEL-ENGAGEABLE SEALING STRIP SEATED IN EACH SAID GROOVE AND EXTENDING FROM SAID SEAT TO SAID HEADPIECE, EACH SAID ADAPTER STRIP HAVING A FACE CONFRONTING SAID FORWARD WALL FACE AND A GROOVE IN SAID STRIP FACE, AND A PANEL-ENGAGEABLE SEALING STRIP SEATED IN EACH SAID LAST-MENTIONED GROOVE AND EXTENDING FROM SAID SILL TO SAID SEAT.