Expansion joint cover

An expansion joint cover having a vapor barrier channel depending from the bellows membrane. Resilient insulation substantially fills the channel, making it possible to attach an insulated vapor-impermeable bellows cover to the expansion joint members in a single operation. A separate layer of foam insulation may be bonded to the underside of the bellows independent of the insulation filling the channel.

FIELD OF THE INVENTION 
This invention relates generally to expansion joints. More particularly, it 
relates to insulated expansion joints and to expansion joint covers for 
use therewith. 
BACKGROUND OF THE INVENTION 
Many building structures incorporate expansion joints to accommodate the 
movement of structural elements as a result of temperature changes or 
seismic activity. In order to prevent moisture from entering the expansion 
joints, it is necessary to protect the joints with a waterproof cover. 
Typical expansion joint covers comprise an elongated bellows the side 
edges of which are connected to metal mounting flanges. The flanges are 
attached to support members of the building structure which are spaced 
from each other on either side of the expansion joint, so that when the 
support members move relative to each other the bellows will be able to 
yield or flex with the movement. Because the bellows remains attached to 
the support members during such movement, the expansion joint cover 
continues to protect the expansion joint against the entry of moisture. 
In addition to waterproofing expansion joints, many architectural and 
engineering structural designs require the joint to be insulated. For the 
insulation to be effective for any length of time it is also necessary to 
provide a vapor barrier to prevent moisture in the form of condensate from 
the interior environment of the building from entering the insulation. 
Therefore, it is common practice when installing an expansion joint cover 
under these conditions to first drape a vapor barrier into the joint 
opening and to then stuff the joint opening above the vapor barrier with 
insulation. Then the preformed expansion joint cover is attached to the 
structural elements on either side of the joint opening. 
Not only is this procedure time consuming, and therefore not economically 
desirable, it is also difficult to maintain high standards of quality 
control. As long as the installation procedure requires the joint cover to 
be fabricated in the field, these problems will continue to exist. Until 
the present invention, there had been no satisfactory way of overcoming 
the drawbacks of this conventional practice. 
SUMMARY OF THE INVENTION 
This invention provides an expansion joint cover which includes insulation 
and vapor barrier means as an integral part. The various functions 
required of an expansion joint can thus be supplied simply by installing a 
preformed cover. The expansion joint cover includes an elongated bellows 
having side edges attached to flange means. The flange means are connected 
to structural support members on either side of the expansion joint when 
the expansion joint cover is installed. Attached to the expansion joint 
cover adjacent the side edge portions of the bellows are the side edge 
portions of an elongated vapor barrier sheet which hangs or drapes down to 
form an elongated channel. Compressible, resilient insulation 
substantially fills the channel. 
With this arrangement it is merely necessary for workmen to install the 
expansion joint cover in the same manner that the bellows alone have been 
installed for years, simply attaching the flanges of the assembly to the 
structural members one either side of the expansion joint. Since it is no 
longer necessary to separately install the various components of an 
expansion joint cover at the building site, the resulting cover is easier 
and and faster to install and is of uniform high quality. Modifications to 
the assembly may be made, including variations in the channel design and 
in the manner of securing the side edges of the vapor barrier channel to 
the expansion joint cover, as explained in more detail hereinafter. 
Other features and aspect of the invention, as well as other benefits of 
the invention, will readily be ascertained from the more detailed 
description of the invention which follows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, the expansion joint cover 10 of the present invention 
comprises an elongated bellows 12 the side edge portions of which are 
attached to flanges 14. The bellows may be formed of any suitable flexible 
material which has adequate resistance to the weather and which is strong 
enough to resist the stresses to which it is exposed during service. 
Examples of suitable materials are an elastomeric membrane such as a 60 
mil sheet of neoprene or EPDM, or a 31.5 mil Tedler/Nitrite laminated 
sheet. 
The mounting flanges 14 are fabricated from a single metal sheet which is 
folded upon itself to form a bifurcated edge for receiving the side edge 
portions of the bellows 12. The flange comprises a flat outer edge portion 
16 of single thickness connected by a sloped transition portion 18 to the 
upper or outer portion 20 of the folded section 22. The outer portion 20 
is folded upon itself to form an interior flange section 24, which is 
folded back to form the lower or inner flange section 26. The sections 24 
and 26 are spaced apart to form the bifurcated edge for receiving the side 
edge portion of the bellows 12. Such an arrangement and its manufacture 
are described in more detail in U.S. Pat. Nos. 3,346,941 and 3, 468,285 to 
Patry et al. If desired, the flange section 26 may be crimped to increase 
the holding power of the bifurcated edge joint. Such an arrangement, 
including gripping teeth resulting from a flange piercing operation, is 
disclosed more fully in application Ser. No. 900,936, filed Oct. 17, 1986 
and assigned to the assignee of this application. 
Although the arrangement depicted is preferred due to its simplicity and 
ease of manufacture, it is not essential that the bifurcated edge opening 
be formed by folding the edges of a metal sheet. For example, U.S. Reissue 
Pat. No. Re. 25,733 to Patry et al disclosed bifurcated edge designs 
formed from both folded and nonfolded sheets. However formed, the 
bifurcated edge clamp should be watertight and can be formed of any 
material suitable to the installation, such as galvanized steel, stainless 
steel, copper and aluminum. It is also contemplated that a suitable 
adhesive may be used to further secure the side edge portions of the 
bellows in the bifurcated edge of the flanges as described in more detail 
in the above-mentioned patents. 
Still referring to FIG. 1, an elongated flexible vapor barrier sheet 28 has 
side edge portions which are also received in the bifurcations of the 
flanges 14 and held in place along with the edge portions of the bellows 
12. The width of the vapor barrier sheet 28 causes the sheet to depend a 
substantial distance from the flanges in a trough-shaped configuration so 
as to form a channel with the underside of the bellows 12. The channel is 
substantially filled with compressible resilient insulation 30 which is 
sufficiently compressed to exert an outward force on the faces of the 
channel. It will be noted that in the preferred form of the invention the 
bellows 12 has a layer of insulation 32 adhered to its underside, so that 
in such an arrangement the insulation 30 actually contacts the layer of 
insulation 32 rather than the membrane 12. 
The vapor barrier sheet may comprise any desired flexible sheet which is 
not permeable to moisture and which offers sufficient tear resistance and 
puncture resistance to withstand the stresses to which it is subjected 
during installation and service. Examples of suitable materials are 
neoprene impregnated fabric, vinyl and MYLAR sheets. 
The insulation contained in the channel formed by the vapor barrier and the 
bellows may be any insulation that has adequate insulating properties and 
which is sufficiently light in weight so as to be supported by the vapor 
barrier sheet. It should be sufficiently compressible to enable it to be 
further compressed by movement of the structural building components 
toward each other, and sufficiently resilient to enable it to recover as 
the building components move away from each other, in all cases being 
maintained in at least slightly compressed condition so as to maintain 
contact with the vapor barrier sheet and the bellows. Suitable inorganic 
fibrous material such as low density glass fiber or refractory fiber 
insulation is preferred, although low density foam insulation having the 
necessary resiliency could also be used. Such material can be inserted 
into the vapor barrier trough either prior to or after the vapor barrier 
sheet is attached to the mounting flanges. Although fibrous insulation 
batts could be used, insulation in roll form is preferred for ease of 
handling during assembly of the expansion joint cover. 
The insulation layer 32, although not essential to the invention, is 
preferred to be used in installations requiring a fully insulated 
expansion joint cover. It not only adds to the insulating value of the 
assembly, but in addition acts as a support for the membrane of the 
bellows 12. The insulation layer 32 preferably is comprised of suitable 
foam insulation which has some structural rigidity and can also be flexed 
or bowed into arcuate shape during installation and during movement of the 
structural building components. Examples of such a foam are closed cell 
polyethylene or closed cell neoprene. 
Referring now to FIG. 2, it can be seen that the side edge portion of the 
bellows 12 is received in the bifurcation of the mounting flange 14 formed 
by the space between the folded sections 24 and 26. In addition, the side 
edge portion 29 of the vapor barrier sheet 28 is also received in the same 
space, between the lower side of the bellows 12 and the lower flange 
section 26. The clamping arrangement of the bifurcation is sufficient to 
hold the trough formed by the vapor barrier sheet in suspended condition. 
Although not shown, it will be understood that the side edge portions of 
the vapor barrier sheet would also be held in place by any adhesive which 
may be used to supplement the gripping engagement of the bellows 12 by the 
bifurcated mounting flange. 
Instead of forming the vapor barrier sheet into the shape of a trough, as 
in FIGS. 1 and 2, the sheet may be formed so as to comprise its own 
enclosed sleeve channel. This arrangement is illustrated in FIG. 3, 
wherein an upper sheet portion 34 connects the side walls of the trough to 
close off the trough into sleeve form. The side edge portions 29 of the 
vapor barrier sheet 28 extend upwardly to the mounting flange as in the 
arrangement of FIGS. 1 and 2. The upper sheet portion 34 would be 
connected as by sewing, in the case of a fabric, or by heat seal, in the 
case of an elastomeric sheet. The upper portion 34 would preferably be 
located so as to engage the underside of the bellows 12 or, if present, 
the underside of the insulation layer 32. 
If desired, the side edge portions of the vapor barrier sheet need not be 
secured in place by the same bifurcated clamp arrangement which grips the 
side edge portions of the bellows but may be attached directly to the 
mounting flanges. As shown in FIG. 4, the side edge portions 31 of the 
vapor barrier sheet 28 are adhered to the bottom surface of the mounting 
flanges 14 by suitable adhesive 36, preferably a contact cement. Although 
the side edge portion 31 is shown as extending substantially to the outer 
edge of the mounting flange, thereby being adhered to the bottom surfaces 
of the outer edge portion 16 and the lower flange section 26, it may be 
adhered only to the section 26 if the dimensions of the flange, the 
strength of the sheet and the holding power of the adhesive 36 are 
adequate to support the insulation-filled vapor barrier trough. Although 
this embodiment is shown in connection with the channel design of FIG. 2, 
it will be appreciated that it could be used in connection with the 
channel design of FIG. 3 as well. 
Referring to FIG. 5, the expansion joint cover is shown in installed 
condition on a roof. The mounting flanges 14 overlie a roofing membrane 38 
which is adhered to mounting blocks 44 and adjacent roof insulation boards 
42. Beneath the mounting blocks and insulation board is the roof deck 40. 
To install the expansion joint cover the assembly is put into place so 
that the mounting flanges 14 are pushed toward each other, resulting in 
the bellows 12 and insulation layer 32 bowing upwardly as shown. The 
mounting flanges are then secured to the mounting blocks 44 on either side 
of the expansion joint, for example by using mechanical fasteners 46 to 
attach the flanges to the mounting blocks 44 at intervals along the length 
of the expansion joint cover. The insulation 30, being highly 
compressible, is squeezed to the resulting narrower shape of the vapor 
barrier trough and extends up into the concave space formed by the flexing 
bellows 12 and insulation layer 32. 
Upon subsequent movement of the support members toward each other, the 
bellows 12 and insulation layer 32 are flexible enough to bow to an even 
greater extent, sufficient to withstand the maximum movement for which the 
joint was designed. The insulation 30 in such case is readily compressed 
the necessary amount. If after the installation of the expansion joint 
cover the support members move away from each other, the bellows and 
insulation layer will readily spring back the amount necessary to lessen 
the curvature of the bowed portion. The insulation 30 has enough 
resiliency to recover or spring back to maintain the insulation in contact 
with the channel formed by the vapor barrier. 
When the expansion joint is relatively long and requires more than one 
length of an expansion joint cover to be used, the ends of the bellows and 
the insulation 30 are abutted, with the butt joint later being covered 
with flashing to maintain a water tight seal. As shown in FIG. 6, the 
vapor barrier sheet 28 is extended beyond one of the ends of the length of 
expansion joint cover of which it is a part, as at 28', so that it can 
overlap the end of the adjacent vapor barrier sheet. In this way the 
continuity of the vapor barrier is preserved between lengths of expansion 
joint covers. Only a relatively small overlap is needed to accomplish 
this, in the order of 4-6 inches. 
It should now be apparent that the invention provides a simple but highly 
effective way of installing insulated expansion joint covers. By 
preassembling the joint covers the quality control is improved and the 
installation time is shortened. Yet the design of the expansion joint 
cover permits factory assembly without radical changes to the existing 
facilities for manufacturing the bellows and mounting flange assembly. It 
is merely necessary to attach the side edge portions of the vapor barrier 
sheet to the mounting flanges during manufacture of the bellows and 
mounting flange assembly, and then subsequently to insert rolls or batts 
of insulation into the channel produced by the vapor barrier. 
It should be understood after reading the foregoing description that the 
invention is not necessarily limited to all the specific structural 
details described, but that changes to certain features of the preferred 
embodiments which do not affect the overall function and concept of the 
invention may be made by those skilled in the art without departing from 
the spirit and scope of the invention, as defined by the appended claims.