Patent Application
20070261342
1. Field of the Invention
This invention relates to roof expansion joint covers and more particularly, to insulated bellows style expansion joint covers.
2. Reported Developments
In today's market there are three basic styles of roof expansion joint covers: insulated bellows, extruded/corrugated bellows, and metal bellows. The major supplier of these bellows include: Johns Manville with the product “Expand-O-Flash” and Cain Manufacturing whose product is nearly identical to that of Johns Manville. All of these products have the foam stopping at the edge of the bellows (which never extends beyond the bellows).
A typical expansion join cover is described, for example, in U.S. Pat. No. 6,962,026 in which the expansion join cover comprises:
The first plate is hingedly attached to a first surface. The second plate is hingedly attached to the first plate and the housing which is hingedly secured to the second surface. In use, the second plate slides within the housing to accommodate variations in separation distance and vertical offset between the two surfaces.
The present invention relates to a factory fabricated expansion joint cover which comprises a foam support extending beyond the edge of the bellows section. The expansion joint cover is an assembly of these components:
The unique part of this assembly is the bonding between the foam and the single-ply roofing membrane. The membrane and the flexible foam are bonded only in the center area of the flexible foam leaving portions of the flexible foam un-bonded.
The expansion joint cover is placed in the opening of a roof system to exclude moisture and debris from entering the structures and allow for independent movement of the structures and materials.
In a typical field fabricated expansion joint cover, a foam rope or molded part is placed in or over the expansion joint opening and the roofing membrane is placed over this section and attached to roof membrane on either side. The membrane may or may not be bonded to the foam or molded part.
A pre-fabricated flexible bellows type expansion joint cover typically is comprised of a weathering membrane, with metal flanges or reinforcements attached to the membrane and a foam support bonded to the underside of the bellows section. When installed the mechanical attachment of the flanges forces the excess bellows width to extend upwards forming the typical flexible bellows shape. In all these products, the attachment of the flanges produces the compression to form the typical flexible bellows shape. In all current products the foam stops at the edge of the flange and does not extend into the joint opening.
In this invention, the sections of foam un-bounded to the membrane extend down into the joint opening and provide the compression of the excess width, forming the typical flexible bellows shape. The un-bonded flanges extend out from the bellows section onto either side and are sealed to the adjacent roofing.
In another embodiment of the present invention, the expansion joint cover is applied roof-to-wall wherein the un-bonded portion of the foam is on one side only. In another aspect, this design corresponds to the roof-to-roof design.
In still another embodiment, the present invention relates to a curb-to-curb or curb-to-wall applications wherein the un-bonded foam extends down into the opening and the un-bonded flanges conform to curbs and/or walls on either side and are sealed to the roofing system.
The weathering membrane is a single-ply roofing membrane of polymeric material such as thermoplastic olefins, chlorinated polyethylene, polyvinyl chloride, chlorosulfonated polyethylene or ethylene propylene dione rubber (EPER). It may also be a polymer membrane equivalent in performance. The flanges can also be ridged materials including metals attached to the membrane.
The adhesive layer which secures the membrane to the substrate may be a butyl compound or other waterproofing compounds such as PVAC (polyvinyl acetate, water-resistant polyvinyl acetate adhesive), EVA (ethylene vinyl acetate) -hot melt adhesive, pressure-sensitive hot melt adhesive atactic polypropylene (APP), base pressure sensitive tapes, polyurethane adhesives, thermoplastic adhesive films based with co-polyamides, thermoplastic adhesive film based with mixed polyolefin and co-polyamide, animal base adhesive, asphalt base adhesive styrol or verstate acrylate types or neoprene rubber cement base adhesive.
A release liner (not-shown) is typically positioned on the top surface of the adhesive layer to facilitate transport and shipping of the expansion joint cover. The release liner may be made of kraft paper, a film-based, waxed, polycoated or polymeric film. The release liner may be treated with a silicone, a fluorocarbon polymer such as TEFLON® or some other release agent with non-sticking properties that enables the release liner to be easily peeled away from the adhesive composition.
The factory fabricated expansion joint cover is an assembly of three components as shown in
The unique part of this assembly is two-fold: The bonding B, between the foam C, and the roofing membrane A, is only at the center of the foam leaving portions of the foam un-bonded to the membrane; and the un-bonded foam extending down into the joint opening is the primary force producing the bellows shape extending above the joint opening as shown in the attached drawings.
When the expansion joint cover is set in place, the un-bonded foam portions “L” are placed down into the expansion joint opening while the attached membrane flanges are spread out onto the adjacent roof decks.
Unique features of the present invention provides benefits including:
This design comprises a vapor barrier W, attached to the roof deck and the wall forming a support to hold the compressible insulation V. The flexible foam is bonded to the roofing membrane from one edge where it meets the wall P, to a point where the bellows meets the cant on the roof deck. The flange R, extends from this point out onto the roofing membrane where it is welded or sealed in place S. The un-bonded portion of the foam extends down into the joint opening U, forming a compression seal against the vertical surface of the roof deck. The flange on the wall side is sealed to the wall O, by welding the flange. This installation forms the typical flexible bellows shape for a roof-to-wall or curb-to-wall installation. The seals of the flanges to the wall and roof will be based on the roofing systems being used.
While there has been shown and described what is considered to be preferred embodiments of the invention, it will be understood that various modifications and changes in form or detail could be readily made without departing from the spirit of the invention. For example the membrane flanges shown could be modified by welding or bonding a ridged nailing strip for particular application needs or the flexible foam could be a round foam tube or rod. It is therefore intended that the invention not be limited to the exact forms described and illustrated, but should be construed to cover all modifications that may fall within the appended claims.
