Abstract:
A foam backed precured joint seal comprising a strip of precured elastomer wider than the joint to be sealed, the strip centrally adhered along its length to an elongated foam backing.

Description:
This is a continuation of Provisional Application Serial No. 60/055,582 filed Aug. 12, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention concerns joints utilized in structures. Even more particularly, the present invention concerns the application of a premanufactured joint seal system (a joint seal system with a finished, dry surface) allowing expansion and contractions of different construction members. 
     2. Description of the Prior Art 
     In the construction of buildings and roads having multiple panels therein, there has long existed the need for joints and other similar means to connect substrates and accommodate the expansion and construction of these substrates due to thermal conditions. Such joints used in highways have been termed horizontal joints. Those utilized in buildings notably in skyscrapers, have been termed vertical joints. Those joints within buildings which interconnect with vertical joints or other vertical members are termed vertical-horizontal joints. 
     In selecting among the known materials to form a vertical joint, architects and specifiers have suggested the use of elastomeric sealant such as silicone sealant or organic based sealant. These types of sealants are normally applied wet into a joint opening. Before solidifying, some sealant types would readily sag and slump within the joint especially wider joints and/or collect dirt due to its wet surface in the uncured stage and/or are permanently deformed due to movement of the construction members while the sealant has not totally cured. This produced an uneven joint, which could not perform in the needed manner nor insure a watertight seal. 
     An example of one method of attempting a silicone seal over a wide vertical joint is described in U.S. Pat. No. 5,335,466 to Langohr. Langohr utilizes an open foam backer to maintain the position of an in place cured sealant strip; the backer and cured sealant strip cooperate to form a pair of grooves which are then filled with an uncured silicone sealant. This system requires a time consuming and labor intensive manufacturing process of depositing and curing a strip of silicone on the foam backing and then an installation process of dual beads of silicone sealant after the foam backing is installed (exposing uncured sealant during application). The resulting seal relies upon four bonds formed by the two beads (each bead forms one bond with the structure and one bond with the cured sealant). Contact between the cured sealant and the structure is only effected by the application of the bead sealant (Col 3, Line 67-Col 4, Line 1). The Langohr system is very wasteful of silicone sealant. The depth of the cured sealant strip (and thus two sealant beads) is substantial to permit sufficient uncured sealant to be added to assure the beads are sufficiently uniform to effect a watertight seal even with flow between application and cure and a smoothing operation for appearance. Further, the three bead appearance is not preferred, particularly where the center bead width differs from the width of the beads of uncured sealant applied. Further still, the foam backer remains adhered to the cured sealant and the bead sealant to provide structural stability to the joint. Another disadvantage is the appearance of the joint if there has been shifting and the space is uneven; the cured sealant will be uniform but the bead sealant will be uneven. Further, wet sealant can collect dirt or debris while curing, creating an unsightly appearance. 
     SUMMARY OF THE INVENTION 
     The present invention provides a decorative and easily formed sealing strip for wide vertical joints, which covers the joint with a performed uniform strip or forms a U-shaped seal by inserting the sealing strip deeper into the joint. The present invention also provides a “dry” outer seal for all types of joints, wide or narrow, vertical or horizontal, which will not deform due to shifting and which will not collect surface debris as the adhesive dries. 
     The seal of the present invention comprises: 
     a) a resilient backing member for compression insertion into a joint 
     b) an elastomeric sealing strip disposed on the backing member and wider than the joint, and 
     c) an adhesive joining a central elongated portion of the sealing strip to the backing member. 
     The backing member holds the sealing strip in place during installation and centers the strip relative to the joint, holding the strip in place while an added adhesive sets. There are various configurations for the backing member to reduce cost, to facilitate insertions, and if needed to minimize adhesion between the backing member and the sealing strip. It is preferred that the sealing strip is adhered to the backing member in a way so that the reaction to expansion or contraction in the joint does not effect the sealant strip. The sealing strip is adhered directly to the structure below the edge on either side with an added adhesive. Thus, adhesive is never exposed to the open. The resultant seal is watertight and yet flexible enough to endure the expansion and contraction of the joint. 
     Other objects, features and advantages of the present invention will become apparent from the subsequent description and appended claims, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first embodiment of the present invention to be deployed to seal two substrates. 
     FIG. 2 is a perspective view of the first embodiment of the present invention deployed to seal two substrates. 
     FIG. 3 is a perspective view of the first embodiment of the present invention deployed in an alternate manner to seal two substrates. 
     FIG. 4 is a perspective view of a second embodiment of the present invention to be deployed to seal two substrates. 
     FIG. 5 is a perspective view of the second embodiment of the present invention deployed to seal two substrates. 
     FIG. 6 is a perspective view of the second embodiment of the present invention deployed in an alternate manner to seal two substrates. 
     FIG. 7 is a perspective view of a third embodiment of the present invention to be deployed to seal two substrates. 
     FIG. 8 is a perspective view of the third embodiment of the present invention deployed to seal two substrates. 
     FIG. 9 is a perspective view of the third embodiment of the present invention deployed in an alternate embodiment to seal two substrates. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference now to FIG. 1, there is shown therein a first embodiment of the present invention, to wit, a seal  10  for a joint  12 . The joint  12  is formed by two adjacent or abutting substrates or slabs  13 ,  14 . The substrates  13 ,  14  may comprise any of the commonly known building materials, such as concrete, brick, steel or other metals, and glass. The substrates  13 ,  14  define the joint  12 . The seal  10  comprises a backer  16  and a strip of an elastomeric sealing strip  18 . The seal  10  is a unitary portable sealing member or expandable joint. Stated another way, the seal  10  is a portable unitary seal that may be manipulated as a single member, and may be installed into a gap or joint in a structure as a one-piece unit. The backer  16  comprises a resilient yet sturdy material. In the preferred embodiment, the backer  16  comprises a flexible open cell polyurethane foam. Other suitable material, such as closed or open flexible foam materials which are commonly used in construction may be used. The backer is wider than the joint  12  so as to require a compression fit into the joint  12 . 
     The sealing strip  18  is at least as wide as the backer  16  and is wider than the joint. The sealing strip  18  is preferably an elastomeric extruded strip of silicone. The strip is preferably thin, flexible, and elongate and is adhered to the backer  16  in the midsection area, leaving on each side a flap  19  which is not attached to the backer and which provides an adhesive area during the installation. A discrete layer of adhesive in the middle section  20  holds the strip  18  to the backer mainly for installation purposes. 
     The seal  10  is alternatively deployed in the joint in the following two manners: 
     a) (FIG. 2) The backer  16  is compressed and inserted within the gap  12  until the sealing strip lays flat upon the substrates  13  and  14  and, the flaps  19  overlap both substrates  13  and  14  (FIG.  2 ). A small amount of adhesive  21  is applied under each side of the strip  18  (flap  19 ) overlapping the substrates  13  and  14 , adhering the strip  18  directly to the top of facing surface of the substrates to create a waterproof or weatherproof seal between the sealing strip  18  and the substrates  13  and  14 . 
     b) The backer  16  is compressed and inserted into the joint-gap so the strip  18  forms a U-shaped seal bending the flaps  19  (FIG. 3) to the outside edges of the joint. A small amount of adhesive  21  is applied under each side of the flaps  19  bridging the substrates  13  and  14 , to create a waterproof or weatherproof seal between the sealing strip  18  and the substrates  13  and  14 . The indented of concave surface gives a final appearance such as a bead of caulk. 
     An alternative embodiment of the invention is shown at FIGS. 4-6. In FIGS. 4-6, reference numerals  112 ,  113 ,  114 ,  118 ,  119 , and  121  refer to features similar to the features having corresponding two-digit reference numerals described in regard to FIGS. 1-3, namely  12 ,  13 ,  14 ,  13 ,  19 , and  21 , respectively. The sealing strip  118  is attached to the foam backing  116  through the use of an elongated groove  124  within the foam backing, preferably T-shaped as shown. The groove  124  may be formed during the extrusion process, and the liquid adhesive  120  applied to the groove, which will then cure after the seal is applied onto the backing. As such adhesives adhere better to the seal than the foam backing, the T-shaped groove greatly improves the adhesion between the seal  118  and the backing  116  while requiring a minimum contact between the seal  118  and the backing  116 . This allows the seal to flex as shown in FIG. 6 without separation from the backing  116 . Alternatively, the sealing strip  118  could be formed (through extrusion) with a mating protrusion (T-shaped in FIGS. 4-6) which could be inserted into the backer  116  and eliminate the need for adhesive. 
     An alternate form of this additional embodiment is shown in FIGS. 7-9, in which a cylindrical foam backing  216  is used. In the embodiment shown in FIGS. 7-9, references numerals  212 ,  213 ,  214 ,  218 , and  221  refer to features similar to the features having corresponding two-digit reference numerals described in regard to FIGS. 1-3, namely  12 ,  13 ,  14 ,  18  and  21 , respectively. The round cross section allows the backing to be inserted more easily and provides greater space for the additional adhesive  221 . For purposes of illustration a triangular groove  224  is shown, which provides the improved adhesion between seal and backing discussed above. 
     In view of the foregoing, it is to be understood that the drawings, discussion and description herein are merely meant to represent particular embodiment of the invention and are not meant to be a limitation upon the practice thereof. It is the following claims, including all equivalents, which define the scope of the invention.