Abstract: An improved horizontal folding door system includes a first folding door, a second folding door, a trolley track, and at least two trolleys. The improved horizontal folding door system covers a large door frame opening of an airplane hanger or some other building structure. Each folding door includes a first door section pivotally attached to a second door section. At least one trolley is attached to a top of each second door section. The trolley track is attached to a top of the door frame opening. The at least two trolleys ride in the trolley track. Each door section is pivotally attached to one side of the door frame opening and is slidably retained by at least one trolley. Preferably, at least two locking pins extend from each second door section to retain each second door frame in an closed or open position.

Abstract: A cupola roof having cupola roof panels with snap-fit edges preferably includes four roof panels. In a first embodiment, there are four combination cupola roof panels. Each combination cupola roof panel has a female snap-fit edge on one side and a male snap-fit edge on the other side. In a second embodiment their are two male cupola roof panels and two female cupola roof panels. The male cupola roof panel has a male snap-fit edge disposed on each side thereof. The female cupola roof panel has a female snap-fit edge disposed on each side thereof.

Abstract: The window buck is made of extruded irregular shapes consisting of a combination of cellulose and polymer compounded specifically to be used in connection with building walls of poured concrete. The combination desirably is a mixture of approximately 70% cellulose and approximately 30% polymer. The cellulose is preferably sawdust, and the polymer preferably is polyethylene.

Abstract: The large overhead bi-fold doors of the present invention are hinged along a centerline and hung by hinges from the top of the door opening. A motor mounted inside and above the door opening is connected to one end of a cable, the other end of which passes around a pulley at the bottom of the door and then upwardly to a latching mechanism located beneath the horizontal hinge line of the doors. When the motor is activated, the cable pulls on a dog or arm connected to a shaft which also carries the hook of a latching device. The hook engages a strike attached to the frame of the building on which the door is mounted, and when the motor is activated, the cable pulls on the dog which disengages the hook from the strike and further tension on the cable by the motor raises the door to an elevated position.

Abstract: The fastening device for interconnecting two flat sheets of metal includes a generally rectangular hole in one of the sheets and a generally H-shaped hole in the other. The H-shaped hole includes a pair of inwardly-facing, tapered portions which are adapted to be bent into the rectangular hole of the other member. The dimensions of the tabs are such that when bent inwardly into the rectangular hole, the edges of the tabs are forced against the edges of the rectangular hole so as to cause the two members to be rigidly and securely interconnected without the necessity of the tabs being bent backwardly behind the rectangular opening in the other member.