U.S. patent application number 10/151316 was filed with the patent office on 2003-11-27 for protective joist cover.
Invention is credited to Gregori, Werner Karl Hermann, Pabedinskas, Arunas Antanas.
Application Number | 20030217519 10/151316 |
Document ID | / |
Family ID | 29548383 |
Filed Date | 2003-11-27 |
United States Patent
Application |
20030217519 |
Kind Code |
A1 |
Pabedinskas, Arunas Antanas ;
et al. |
November 27, 2003 |
Protective joist cover
Abstract
A protective joist cover is adapted to cover a joist. The joist
cover includes a top section and a bottom section. The top section
has a top end web and a pair of substantially parallel top side
webs each extending from an end of the top end web. The top side
webs are substantially perpendicular to the top end web. The bottom
section has a bottom end web and a pair of substantially parallel
bottom sides webs each extending from an end of the bottom end web.
The bottom side webs are substantially perpendicular to the bottom
end web. The pair of top side webs and the pair of bottom side webs
are dimensioned such that they overlap when positioned over the
joist. The protective joist cover is made of a thermoplastic
material.
Inventors: |
Pabedinskas, Arunas Antanas;
(Etobicoke, CA) ; Gregori, Werner Karl Hermann;
(Hawkstone, CA) |
Correspondence
Address: |
Ralph A. Dowell
Dowell & Dowell, P.C.
Suite 309
1215 Jefferson Davis Hwy.
Arlington
VA
22202
US
|
Family ID: |
29548383 |
Appl. No.: |
10/151316 |
Filed: |
May 21, 2002 |
Current U.S.
Class: |
52/58 ;
52/300 |
Current CPC
Class: |
B29C 66/71 20130101;
B29K 2027/06 20130101; B29C 66/1162 20130101; B29C 2793/0081
20130101; B29C 66/1122 20130101; B29C 66/71 20130101; B29C 66/547
20130101; B29C 66/71 20130101; E04C 3/29 20130101; E04F 15/10
20130101; B29C 65/48 20130101; E04B 5/12 20130101; B29C 65/562
20130101; B29C 63/22 20130101; B29K 2055/02 20130101 |
Class at
Publication: |
52/58 ;
52/300 |
International
Class: |
E04D 001/36 |
Claims
What is claimed as the invention is:
1. A protective joist cover adapted to cover a joist having a
width, the protective joist cover comprising; a top section having
a top end web and a pair of substantially parallel top side webs
each extending from an end of the top end web and being
substantially perpendicular to the top end web; a bottom section
having a bottom end web and a pair of substantially parallel bottom
sides webs each extending from an end of the bottom end web and
being substantially perpendicular to the bottom end web and whereby
the pair of top side webs and the pair of bottom side webs are
dimensioned such that they overlap when positioned over the joist;
and the protective joist cover being of a thermoplastic
material.
2. A protective joist cover as claimed in claim 1 wherein the
distance between the inside surfaces of the pair of top side webs
generally equals the width of the joist plus the thickness of the
pair of bottom side webs.
3. A protective joist cover as claimed in claim 2 wherein the
distance between the inside surfaces of the pair of bottom side
webs generally equals to distance between the inside surfaces of
the pair of top side webs.
4. A protective joist cover as claimed in claim 2 wherein the
distance between the inside surface of the pair of bottom side webs
generally equals the width of the joist.
5. A protective joist cover as claimed in claim 2 wherein the
overlap is greater than 0.5 inches.
6. A protective joist cover as claimed in claim 2 wherein the
overlap is between 0.5 and 2 inches.
7. A protective joist cover as claimed in claim 1 wherein the pair
of bottom side webs is substantially longer than the pair of top
side webs.
8. A protective joist cover as claimed in claim 7 wherein the
length of the pair of top side webs is between 0.5 and 2
inches.
9. A protective joist cover as claimed in claim 2 wherein the width
of the joist is between 1.25 and 1.75 inches.
10. A protective joist cover as claimed in claim 1 wherein the pair
of top side webs and the pair of bottom side webs have the same web
thickness and the distance between the inside surfaces of the pair
of bottom side webs and the inside surface of the pair of top side
webs is equal to the distance between the inside surfaces of the
pair of top side webs and is equal to the width of the joist plus
the web thickness.
11. A protective joist cover as claimed in claim 10 wherein the
overlap is greater than 0.5 inches.
12. A protective joist cover as claimed in claim 1 wherein the
inside surface of the top end web has a plurality of detents
extending inwardly therefrom thereby providing an airspace between
the top end web and the joist when positioned over the joist.
13. A protective joist cover as claimed in claim 1 wherein the
inside surface of the bottom end web has a plurality of detents
extending inwardly therefrom thereby providing an airspace between
the bottom end web and the joist when positioned over the
joist.
14. A protective joist cover as claimed in claim 2 wherein the
inside surface of each of the pair of top side webs has a plurality
of detents extending inwardly therefrom thereby providing an
airspace between the top side web and the joist when positioned
over the joist.
15. A protective joist cover as claimed in claim 10 wherein the
inside surface of the at least one of the pair of top side webs has
a plurality of detents extending inwardly therefrom thereby
providing an airspace between the top side web and the joist when
positioned over the joist and the inside surface of the at least
one of the pair of bottom side webs has a plurality of detents
extending inwardly therefrom thereby providing an airspace between
the bottom side web and the joist when positioned over the
joist.
16. A protective joist cover as claimed in claim 3 wherein the
inside surface of each of the pair of bottom side webs has a
plurality of detents extending inwardly therefrom thereby providing
an airspace between the bottom side web and the joist when
positioned over the joist and the inside surface of each of the
pair of top side webs has a plurality of detents extending inwardly
therefrom thereby providing an airspace between the top side web
and the joist when positioned over the joist.
17. A protective joist cover as claimed in claim 3 wherein a distal
end portion of each of the pair of the bottom side webs is offset
inwardly from a remainder portion of the respective bottom side web
and is generally parallel thereto.
18. A protective joist cover as claimed in claim 1 wherein the top
end web, the pair of top side webs, the bottom end web and the pair
of bottom side webs all have the same thickness.
19. A protective joist cover as claimed in claim 1 wherein said
thermoplastic material is chosen from the group consisting of a
thermoplastic resin, a blend of thermoplastic resins and a mixture
of thermoplastic resins.
20. A protective joist cover as claimed in claim 1 wherein said
thermoplastic resin is chosen from the group consisting of a virgin
resin, a recycled resin, and a mixture of virgin and recycled
resins.
21. A protective joist cover as claimed in claim 1 wherein said
thermoplastic material contains a filler.
22. A protective joist cover as claimed in claim 21 wherein the
filler is chosen from the group consisting of glass fibers, carbon
fibers, metallic fibers, thermoplastic fibers and mixtures
thereof.
23. A protective joist cover as claimed in claim 21 wherein the
filler is one of cellulosic fibers and cellulosic particles derived
by one of the comminution and attrition by one of grinding and
milling one of wood, plant matter and agricultural byproducts
chosen from the group of hulls, husks, shells, straws and mixtures
thereof.
24. A protective joist cover as claimed in claim 21 wherein the
filler is cellulosic fibers from one of recycling and a byproduct
of paper production.
25. A protective joist cover as claimed in claim 21 wherein said
filler is a mineral filler chosen from the group consisting of
talc, mica, calcium carbonate and clays.
26. A protective joist cover as claimed in claim 1 where the
protective joist cover is manufactured as a hollow profile and
subsequently cut into the top section and the bottom section.
27. A protective joist cover as claimed in claim 2 where the
protective joist cover is manufactured as a hollow profile and
subsequently cut into the top section and the bottom section.
28. A protective joist cover as claimed in claim 3 where the
protective joist cover is manufactured as a hollow profile and
subsequently cut into the top section and the bottom section.
29. A protective joist cover as claimed in claim 4 where the
protective joist cover is manufactured as a hollow profile and
subsequently cut into the top section and the bottom section.
30. A protective joist cover as claimed in claim 7 where the
protective joist cover is manufactured as a hollow profile and
subsequently cut into the top section and the bottom section.
31. A protective joist cover as claimed in claim 10 where the
protective joist cover is manufactured as a hollow profile and
subsequently cut into the top section and the bottom section.
32. A hollow profile adapted to be selectively cut into a
protective joist cover adapted to cover a joist having a width, the
protective joist cover comprising; a top section having a top end
web and a pair of substantially parallel top side webs each
extending from an end of the top end web and being substantially
perpendicular to the top end web; a bottom section integrally
attached to the top section and adapted to be selectively cut
therefrom, the bottom section having a bottom end web and a pair of
substantially parallel bottom sides webs each extending from an end
of the bottom end web and being substantially perpendicular to the
bottom end web and whereby the pair of top side webs and the pair
of bottom side webs are dimensioned such that they overlap when
positioned over the joist; and the hollow profile being of a
thermoplastic material.
Description
FIELD OF THE INVENTION
[0001] This invention relates to decks and other outside
constructions, and in particular to a protective joist cover which
is meant to prevent moisture damage to joists and to prevent
leaching of chemical preservatives when treated lumber joists are
used in building a deck or other outside constructions.
BACKGROUND OF THE INVENTION
[0002] The majority of decks constructed in North America are
constructed from wood, this includes the support structure as well
as the decking surface. However, with age and exposure to moisture,
wood can split, warp, twist, splinter and rot. These effects are
most apparent on the horizontal decking surfaces where water can
collect, especially if the deck boards become cupped. As a result,
a number of manufacturers have started offering non-wood decking
products which can be used as an alternative to wood decking. These
products, are said to offer a number of advantages over wood,
particularly relating to the moisture resistance of the materials
used in their manufacture. Non-wood decking products are currently
produced from a wide range of materials including thermosetting and
thermoplastic resins with and without fillers. There are non-wood
decking products produced with glass fiber reinforced thermosetting
resins via pultrusion. However, these products are generally
substantially more expensive than those products made from
thermoplastic resins, which are typically produced via extrusion
from virgin and recycled resins with and without fillers. Most, if
not all, of the non-wood decking products produced with
thermoplastic resins are made from either polyethylene (PE),
polypropylene (PP), polystyrene (PS) or polyvinyl chloride (PVC),
which are available quite readily in virgin or less readily in
recycled forms. Non-wood decking products are available that are
made with unfilled PE, PS and PVC as well as filled PE, PP and PVC.
The most common type of fillers used in producing thermoplastic
non-wood decking products are glass fibers and cellulosic fibers.
Glass fibers are used to increase the strength of the non-wood
decking products, while cellulosic fibers can be used to both
increase the strength of the products and to reduce their cost, as
the cellulosic fibers typically used are substantially cheaper than
the resins to which they are added.
[0003] While there are a growing number of manufacturers of these
non-wood decking products, most of these manufacturers recommend
against using their products as framing members or joists, as they
are not designed for that purpose or they do not have the strength
and stiffness required by the application. Typically, the
manufacturers of the non-wood decking products recommend using wood
to construct the structure on which the non-wood decking product is
installed. This results in a decking surface which may have a
lifetime guarantee, while the wooden structure supporting it is
still prone to moisture damage and may need replacement if the
damage is severe enough. The effects of moisture on the wooden
support structure can be minimized by using naturally moisture
resistant wood species such as cedar or redwood, which are usually
sold at a substantial premium to less moisture resistant species.
However, while using moisture resistant wood species delays the
decay of the wood, it does not prevent splitting, warping, twisting
and splintering of the wood which is caused by repeated cycles of
the wood getting wet and drying out.
[0004] A more economical solution than using moisture resistant
wood species as joists when building decks with the non-wood
decking products, has been to use lumber treated with various
preservative formulations. The various chemical formulations used
in treating lumber typically act as fungicides which enhance the
moisture resistance of the wood by killing fungi which can lead to
rot and decay. However, according to the Canadian Environment
Ministry, all chemical wood preservatives are classified as
pesticides as they achieve decay control as a result of their
significant toxicity, and that while the potency of the various
preservatives varies, all are poisonous to some degree and are
potentially hazardous to human and other forms of life. In
addition, the effect of the pressure treating can decrease over
time as the preservatives leach out of the wood. As the
preservatives leach out of the wood, it increases the potential for
someone coming into contact with increased concentrations of these
toxic chemicals. In addition the leached preservatives may also
contaminate the soil near the structures built with treated
lumber.
[0005] As a result of concerns regarding the toxicity of the
arsenic and chromium compounds which result from the breakdown of
the wood preservative chromated copper arsenate (CCA), the United
States Environmental Protection Agency announced the phase-out of
CCA treated lumber by the treated lumber industry by Dec. 31, 2003.
At the time of the announcement in February of 2002, CCA treated
lumber accounted for over 80% of pressure treated lumber sold in
North America. Other chemical preservatives are currently
available, with the most likely successor to CCA being alkaline
copper quaternary (ACQ), which is substantially more expensive than
CCA and is expected to result in higher treated lumber prices.
However, as mentioned before, all of these preservatives prevent
wood decay as a result of their toxicity and could be potentially
hazardous to people.
[0006] One means available to reduce the amount of the
preservatives that leach out of treated lumber, is to coat the
treated lumber with paint, stain or other sealing agent. This is
also a recommended means for reducing the effects of moisture
damage to both moisture resistant and other wood species. However,
these coatings need to be maintained and have to be reapplied
periodically and the preservatives in treated lumber can interfere
with the adhesion of the coatings to the surface of the wood. In
addition, as the joists of most decks are not as readily accessible
as the deck surfaces, it may be quite difficult to maintain the
joists once the decking surface has been installed. As a result, it
may be possible to have a relatively maintenance free decking
surface with the non-wood decking products, while having to paint
or treat the joists every year.
[0007] Several earlier patents have tried to address some of the
above concerns. U.S. Pat. No. 4,516,756 and U.S. Pat. No. 6,260,328
describe sleeves made of moisture resistant thermoplastic resins
into which pieces of lumber can be inserted. The purpose of the
sleeves is to prevent moisture from reaching the wood. As the
dimensions of stock lumber can vary by as much as 1/8 of an inch in
both height and width, having a fixed size sleeve could result in
the sleeve not fitting pieces of lumber of above average dimensions
or being unacceptably loose on pieces of below average dimensions.
U.S. Pat. No. 4,181,764 and U.S. Pat. No. 6,231,994 both deal with
the problem of the varying dimensions of lumber by extruding a
thermoplastic coating directly onto the lumber, while U.S. Pat. No.
6,231,994 is also directed at preventing leaching of preservative
meant to prevent the decay of the lumber. However, both approaches,
coating lumber with thermoplastics and using thermoplastic sleeves,
are not suitable for use with an existing deck, in the case, for
instance, when a wood decking surface is to be replaced with a
non-wood decking product and it is desired to retrofit the existing
joists with a protective thermoplastic covering.
[0008] Therefore it would be desirable to provide a product which
can be used to reduce the leaching of and exposure to the
preservatives used in treated lumber joists and would eliminate the
need for periodic maintenance required by paints or coatings which
are currently used to reduce the detrimental effects of moisture on
wood. It would also be desirable if such a product could be used
both in new construction and in retrofitting existing structures.
In addition, it would be desirable to have a product that can
compensate for the varying dimensions of standard sized lumber.
Finally, it would be advantageous if the product were made of a
moisture resistant material.
SUMMARY OF THE INVENTION
[0009] A protective joist cover is adapted to cover a joist. The
joist cover includes a top section and a bottom section. The top
section has a top end web and a pair of substantially parallel top
side webs each extending from an end of the top end web. The top
side webs are substantially perpendicular to the top end web. The
bottom section has a bottom end web and a pair of substantially
parallel bottom sides webs each extending from an end of the bottom
end web. The bottom side webs are substantially perpendicular to
the bottom end web. The pair of top side webs and the pair of
bottom side webs are dimensioned such that they overlap when
positioned over the joist. The protective joist cover is made of a
thermoplastic material.
[0010] The present invention comprises a protective joist cover
which consists of a top section and a bottom section which are
preferably made from a moisture resistant thermoplastic material.
The top section consists of a top end web which sits against the
top of a joist when installed and two top side webs which are
substantially parallel and extend downwardly from and perpendicular
to the top end web. Similarly, the bottom section of the protective
joist cover consists of a bottom end web which sits against the
bottom of a joist when installed and two bottom side webs which are
substantially parallel and extend upwardly from and perpendicular
to the bottom end web. When installed, the ends of the top side
webs overlap the ends of the bottom side webs, thereby effectively
enclosing the joist. The top and bottom sections may overlap such
that the bottom side webs fit between the top side webs and the
sides of the joist. Alternatively the top and bottom sections may
overlap such that one bottom side web fits between a top side web
and one side of the joist and the other bottom side web fits
outside of the other top side web which fits next to the other side
of the joist.
[0011] In a preferred embodiment of the invention, the two sections
of the protective joist cover are produced by selectively cutting a
single hollow profile into two pieces. In addition, the joist cover
can be preferably dimensioned so that it readily fits standard
lumber joist sizes, while allowing for some adjustability to
compensate for joists which are above average or below average in
size. The protective joist cover of this invention might be
designed as to specifically fit one size of joist (such as only
2.times.8's) or to fit two successive sizes of joists (such as
2.times.6's and 2.times.8's or 2.times.8's and 2.times.10's). An
alternate embodiment of the present invention has a bottom section
whose side webs are designed so that the outside dimensions at the
beginning of side webs is the same as the outside dimension of the
top side webs, while the outside dimension at the ends of the
bottom side webs is the same as the inside dimension of the top
side webs. Additionally, the joist cover can be formed with surface
features on the inside surfaces of the top and bottom sections
which are designed to space the joist cover away from the joist for
the purpose of properly positioning the joist cover or for allowing
for the circulation of air along the surfaces of the joist.
[0012] Preferably the protective joist cover is made from a
moisture resistant material such as a thermoplastic resin which may
or may not contain fillers whose purpose is to either increase the
strength and stiffness of the profile or to reduce its cost.
Further, the choice of the moisture resistant material should yield
a product with sufficient strength and rigidity that minimum effort
is required for installation of the product.
[0013] Other features and advantages of this invention will become
apparent from the following description taken in conjunction with
the accompanying drawings wherein are set forth, by way of
illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and include
exemplary embodiments and illustrate various features and designs
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will now be described by way of example only,
with reference to the accompanying drawings, in which:
[0015] FIG. 1 is a cross-sectional view of an embodiment of a
protective joist cover constructed in accordance with the present
invention;
[0016] FIG. 2 is a perspective view of the embodiment of the
protective joist cover shown in FIG. 1;
[0017] FIG. 3 is a cross-sectional view of a hollow profile which
can be selectively cut to produce the embodiment of the protective
joist cover of the present invention shown in FIG. 1;
[0018] FIG. 4 is a perspective view of a hollow profile which can
be selectively cut to produce the embodiment of the protective
joist cover of the present invention shown in FIG. 1;
[0019] FIG. 5a is a cross-sectional view of the installation of the
embodiment of the protective joist cover shown in FIG. 1 on a wood
2.times.8;
[0020] FIG. 5b is a cross-sectional view of the installation of the
embodiment of the protective joist cover shown in FIG. 1 on a wood
2.times.6;
[0021] FIG. 6a is a cross-sectional view of an alternate embodiment
of a hollow profile which can be selectively cut to produce an
alternate embodiment of the protective joist cover of the present
invention;
[0022] FIG. 6b is a cross-sectional view of an alternate embodiment
of the protective joist cover shown installed over a wood 2.times.8
joist;
[0023] FIG. 6c is a cross-sectional view of an alternate embodiment
of the protective joist cover shown installed over a wood 2.times.6
joist;
[0024] FIG. 7a is a cross-sectional view of a second alternate
embodiment of a hollow profile which can be selectively cut to
produce a second alternate embodiment of the protective joist cover
of the present invention;
[0025] FIG. 7b is a cross-sectional view of a second alternate
embodiment of the protective joist cover shown installed over a
wood 2.times.8 joist;
[0026] FIG. 7c is a cross-sectional view of a second alternate
embodiment of the protective joist cover shown installed over a
wood 2.times.6 joist;
[0027] FIG. 8a is a cross-sectional view of a third alternate
embodiment of a hollow profile which can be selectively cut to
produce a third alternate embodiment of the protective joist cover
of the present invention;
[0028] FIG. 8b is a cross-sectional view of a third alternate
embodiment of the protective joist cover shown installed over a
wood 2.times.8 joist;
[0029] FIG. 8c is a cross-sectional view of a third alternate
embodiment of the protective joist cover shown installed over a
wood 2.times.6 joist;
[0030] FIG. 9a is a cross-sectional view of a fourth alternate
embodiment of a hollow profile which can be selectively cut to
produce a fourth alternate embodiment of the protective joist cover
of the present invention;
[0031] FIG. 9b is a cross-sectional view of a fourth alternate
embodiment of the protective joist cover of the present
invention;
[0032] FIG. 9c is a cross-sectional view of the fourth alternate
embodiment of the protective joist cover shown in FIG. 9b, shown
installed over a wood 2.times.8 joist;
[0033] FIG. 10a is a cross-sectional view of a fifth alternate
embodiment of a hollow profile which can be selectively cut to
produce a fifth alternate embodiment of the protective joist cover
of the present invention;
[0034] FIG. 10b is a cross-sectional view of a fifth alternate
embodiment of the protective joist cover of the present
invention;
[0035] FIG. 10c is a cross-sectional view of the fifth alternate
embodiment of the protective joist cover shown in FIG. 10b, shown
installed over a wood 2.times.8 joist;
[0036] FIG. 11a is a cross-sectional view of a sixth alternate
embodiment of a hollow profile which can be selectively cut to
produce a sixth alternate embodiment of the protective joist cover
of the present invention;
[0037] FIG. 11b is a cross-sectional view of a sixth alternate
embodiment of the protective joist cover of the present
invention;
[0038] FIG. 11c is a cross-sectional view of the sixth alternate
embodiment of the protective joist cover shown in FIG. 11b, shown
installed over a wood 2.times.6 joist;
[0039] FIG. 12a is a cross-sectional view of a seventh alternate
embodiment of a hollow profile which can be selectively cut to
produce a seventh alternate embodiment of the protective joist
cover of the present invention:
[0040] FIG. 12b is a cross-sectional view of a seventh alternate
embodiment of the protective joist cover of the present invention;
and
[0041] FIG. 12c is a cross-sectional view of the seventh alternate
embodiment of the protective joist cover shown in FIG. 12b, shown
installed over a wood 2.times.8 joist.
DETAILED DESCRIPTION OF THE INVENTION
[0042] Although the invention will be described in terms of
specific embodiments, it will be readily apparent to those skilled
in the art that various modifications, rearrangements and
substitutions can be made without parting from the spirit of this
invention. For example, the invention herein is described as a
joist cover but it will be appreciated by those skilled in the art
that it could also be used to cover other building members.
[0043] FIG. 1 shows a cross-section of one embodiment of a
protective joist cover of this invention, while FIG. 2 shows a
perspective view of the same embodiment. The protective joist cover
consists of a top section 1 and a bottom section 2. The top section
1 consists of a top end web 3 and two top side webs 4 and 5 which
extend downwardly from the opposed ends 6 and 7 of the top end web
3 and are generally parallel to each other and perpendicular to the
top end web 3. Similarly, the bottom section 2 consists of a bottom
end web 8 and two bottom side webs 9 and 10 which extend upwardly
from the ends 11 and 12 of the bottom end web 8 and are generally
parallel to each other and perpendicular to the bottom end web 8.
In this embodiment, the ends 13 and 14 of the top side webs 4 and 5
and the ends 15 and 16 of the bottom side webs 9 and 10 are angled
to aid in the installation of the protective joist cover.
[0044] As it can be substantially easier to extrude one hollow
profile than two separate open profiles, and to do so at higher
production rates, it is preferred to form the two sections of the
protective joist cover by selectively cutting into two pieces a
single generally rectangular hollow profile which has been extruded
from a moisture resistant thermoplastic material which may or may
not contain a filler. As is shown in FIG. 3, if the hollow extruded
profile 17, shown in a perspective view in FIG. 4, is selectively
cut as indicated by lines 18 and 19, then the two sections 1 and 2
of the protective joist cover shown in FIG. 1 are formed. The
hollow extruded profile 17 can have inside corners 20 and outside
corners 21 with radii that have been chosen to ensure the strength
of the corners during installation and to provide stress relief for
the corners in case there are any forces which are concentrated at
the corners when the resulting joist cover is installed.
[0045] FIG. 5a illustrates the installation of the protective joist
cover shown in FIG. 1 on a nominal wood 2.times.8 22 (actually
about 1.5 inches wide and about 7.5 inches tall). As can be seen,
when the protective joist cover is installed, the end portions 23
and 24 of the bottom side webs 9 and 10 are positioned between the
end portions 25 and 26 of the top side webs 4 and 5. When the
protective joist cover is installed on a joist, the top side web
end portions 25 and 26 and the bottom side web sections 23 and 24
should overlap each other and effectively enclose the joist. The
length of the top side webs 4 and 5 and the bottom side webs 9 and
10 should be such that the length of the overlaps 29 and 30 are
long enough to prevent water from wicking up between the top side
webs 4 and 5 and the bottom side webs 9 and 10 while allowing for
some adjustability due to the variation in the height of different
2.times.8's. In order to fasten the protective joist cover to the
joist 22, it is only necessary to place fasteners along the length
of the joist in the regions 29 and 30 where the top side webs 4 and
5 and the bottom side webs 9 and 10 overlap. Fasteners such as
screws, nails, brads, staples, etc. may be appropriate depending on
the thermoplastic material from which the protective joist cover
has been made.
[0046] FIG. 5b illustrates the installation of the protective joist
cover shown in FIG. 1 on a nominal wood 2.times.6 31 (actually
about 4.5 inches wide and about 5.5 Inches tall). As can be seen,
the protective joist cover fits the 2.times.6 31 in addition to
fitting the 2.times.8 22. However, depending on the material used
to produce the joist cover, the resulting bending in the beginning
portions 32 and 33 of the bottom side webs 4 and 5 could be
unacceptable as the stresses in the material might cause the bottom
section 2 of the joist cover to break or crack, particularly at the
corners 34 and 35 where the stresses would be concentrated.
[0047] FIG. 6a shows an alternative embodiment of a hollow profile
36, which when cut along lines 37 and 38 forms the alternative
embodiment of the protective joist cover of this invention which is
shown in FIG. 6b. When this embodiment of the protective joist
cover of this invention is installed on a joist, one bottom side
web end portion 39 is positioned between one top side web end
portion 40 and one side of the joist 41, while the other top side
web end portion 42 is positioned between the other bottom side web
end portion 43 and the other side of the joist 44. As can be seen
in FIG. 6c, this embodiment does not result in the bending of the
bottom side webs 45 and 46 when the joist cover is installed on a
2.times.6. However, as a result of the side web end portion 43
being positioned outside of top side web end portion 42, there is
an increased possibility for water to penetrate inside of the joist
cover. If the joist cover is made from polyvinyl chloride (PVC or
vinyl) or acrylonitrile-butadiene-styrene (ABS) resins, then the
adhesives which are used to join PVC and ABS pipe and fittings
might be used to form a watertight connection between the top
section 47 and the bottom section 48 of this embodiment of the
protective joist cover, if these adhesives are applied to the
adjoining surfaces 49 and 50.
[0048] FIG. 7a shows a second alternative embodiment of a hollow
profile 51, which when cut along lines 52 and 53 forms the
alternative embodiment of the protective joist cover of this
invention which is shown in FIG. 7b, installed on a 2.times.8. In
this embodiment, the hollow profile 51 has been extruded with
additional inside surface features. The surface features or detents
54 extend inwardly on the inside surface of the top end web 55 and
the surface features 56 on the inside surface of the bottom end web
57 serve to space the joist cover away from the top end of the
joist 58 and the bottom end of the joist 59. This allows for air to
circulate between the joist cover and the joist and to keep any
moisture which might collect on the inside surface of the bottom
end web 57 from contacting the joist until it evaporates or drains
out. The surface features or detents 60 and 61 extend inwardly on
the inside surfaces 62 of the top side webs 63 and the inside
surfaces 64 of the bottom side webs 65 are meant to properly center
the joist cover on the 2.times.8 joist 66. In this case the surface
features 60 and 61 are shaped to allow for easier installation of
the joist cover on the joist 66. FIG. 7c shows that when the same
protective joist cover shown in FIG. 7b is installed on a 2.times.6
joist 67, again there is bending of the bottom side webs 65, as was
seen in FIG. 5b, which might result in unacceptable stresses in the
joist cover when it is installed.
[0049] FIG. 8a shows a third alternative embodiment of a hollow
profile 69, which when cut along lines 70 and 71 forms the
alternative embodiment of the protective joist cover of this
invention which is shown in FIG. 8b installed on 2.times.8 68. As
was seen, in FIG. 6b and FIG. 6c, this offset arrangement of the
top side webs 72 and 72a and the bottom side webs 73 and 73a gives
a protective joist cover whose sides do not get bent when the joist
cover is installed on a 2.times.6 74, as is shown in FIG. 8c.
Again, surface features or detents 75 can be provided on the inside
surfaces 76 of the top side webs and the inside surfaces 77 of the
bottom side webs to help properly position the protective joist
cover on a joist. In this case with the offset arrangement of the
top side webs 72 and 72a and the bottom side webs 73 and 73a, the
surface features 75 would only be included the top side web 72 and
bottom side web 73 which are spaced away from the sides 78 and 79
of the joist 68. Even though no surface features are shown on the
top web inside surface 80 and bottom end web inside surface 81 for
this particular embodiment with the offset arrangement of the top
side webs 72 and 72a and bottom side webs 73 and 73a, that does not
preclude them from being included in other embodiments of the
protective joist cover of this invention. However, as was noted
before in regard to FIGS. 6a, 6b and 6c, while this offset
arrangement of the side webs allows for easier use of the
protective joist cover on 2.times.6's or 2.times.8's, there is the
worry of water penetrating the joist cover between the adjoining
surfaces 82 of top side web 72a and bottom side web 73.
[0050] FIG. 9a shows a fourth alternative embodiment of a hollow
profile 83, which when cut along lines 84 and 85 forms the
alternative embodiment of the protective joist cover of this
invention which is shown in FIG. 9b. In this embodiment, the top
end web 86 and the bottom end web 87 are not the same length in
that the bottom end web 87 is shorter than the top end web 86 by
the thickness of the side webs 88 and 89 of the hollow profile 83.
As a result, the side webs of the hollow profile 88 and 89 are not
completely parallel when the profile is extruded. However after
hollow profile 83 is cut to produce the top section 90 and bottom
section 91 of this embodiment of the protective joist cover of this
invention, and the joist cover is installed on a 2.times.8 92, the
slope of the profile's side webs 88 and 89 is no longer evident, as
can be seen in FIG. 9c. It will be appreciated by those skilled in
the art that if this embodiment of the joist cover were installed
on a 2.times.6, the bottom side webs 93 would not exhibit any
bending as was seen in FIGS. 5b and 7c. With this particular
configuration of the protective joist cover of this invention,
surface features or detents 94 can be included on the inside
surface 95 of the top end web 86 and the inside surface 96 of the
bottom end web 87. However, it would only be practical to provide
surface features 97 on the inside surfaces 98 of the top side webs
99. For the particular embodiment of the protective joist cover
shown in FIGS. 9b and 9c, the bottom side webs 93 would not exhibit
bending as was seen in FIGS. 5b and 7c when the protective joist
cover was installed on a 2.times.6, and it could therefore be
easily used on both 2.times.6's and 2.times.8's without the concern
of moisture penetration as was seen in the embodiments of the joist
cover shown in FIGS. 6b and 8b. However, when this particular
embodiment of the joist cover is installed on a 2.times.8, there
are two gaps 100 between the inside surfaces 98 of the top side
webs 99 and the sides of the joist 101 where the top side webs are
not substantially supported. In addition the outside surfaces 102
of the top side webs 99 are not in line with the outside surfaces
103 of the bottom side webs 93. Both of these issues might be of
concern when trying to fasten such things as railing posts to a
covered joist or trying to fasten two covered joints together to
form a beam.
[0051] FIG. 10a shows a fifth alternative embodiment of a hollow
profile 104, which when cut along lines 105 and 106 forms the
alternative embodiment of the protective joist cover of this
invention which is shown in FIG. 10b. This embodiment of the
protective joist cover of this invention addresses the issues
raised with the previously described embodiment. When installed on
a 2.times.8 107, the outside surfaces 108 of the top side webs 109
are in line with outside surfaces 110 of the beginning portions 111
of the bottom side webs, while the bottom side web end portions 112
are positioned between the top side web end portions 113 and the
sides 114 of joist 107. In this particular embodiment of the joist
cover of this invention, surface features are provided at multiple
locations along the inside surfaces of the top side webs 109 which
are meant to better support the top side webs 109 when forces are
exerted on the outside surfaces 108 of the top side webs 109.
Similarly, surface features 116 are provided at multiple locations
along the inside surfaces of bottom side webs 111, again to better
support them. This embodiment shows an alternate surface treatment
124 applied to top end web 125 and bottom end web 126. Surface
treatment 124 is a plurality of groves formed in the inside surface
of the web.
[0052] While the last embodiment of the protective joist cover of
this invention addresses the issues raised with the previously
described embodiment, it can only effectively be used with
2.times.8 joists as it is not possible to overlap the top and
bottom side webs so that the top and bottom end webs rest against
the top and bottom of a 2.times.6. As such, FIG. 11a shows a sixth
alternative embodiment of a hollow profile 117, which when cut
along lines 118 and 119 form the alternative embodiment of the
protective joist cover of this invention, shown in FIG. 11b, which
has the same characteristics of the embodiment of the protective
joist cover shown in FIG. 10b, but is dimensioned specifically for
use with 2.times.6 joists, as is shown in FIG. 11c. Protective
joist covers for 2.times.10's and 2.times.12's incorporating the
same features can also be easily designed.
[0053] FIG. 12a shows the hollow profile shown in FIG. 3, but in
order to produce a seventh alternate embodiment of the protective
joist cover of this invention, the hollow profile is cut along
lines 120 and 121 and form the joist cover which is shown in FIGS.
12b and 12c. As can be seen, in this embodiment of the protective
joist cover, the top side webs 127 and the bottom side webs 128 are
substantially different in length. While this may preclude using
the same joist cover on 2.times.6's and 2.times.8's, it may offer
other advantages such as reducing the stresses in corners 122 and
123 when the cover is installed.
[0054] It will be appreciated by those skilled in the art that the
protective joist cover of this invention might be dimensioned as to
specifically fit one size of joist (such as only 2.times.8's) or to
fit two successive sizes of joists (such as 2.times.6's and
2.times.8's or 2.times.8's and 2.times.10's). Typically a minimum
overlap of 0.5 inches is preferred. However where the joist covers
are dimensioned to fit two successive sizes of joists the overlap
may range between 0.5 inches and 3 inches. Typically the length of
the two top side webs will be between 0.5 inches and 5.5 inches for
2.times.6's; 0.5 Inches and 7.5 inches for 2.times.8's; 0.5 inches
and 9.5 inches for 2.times.10's; and 0.5 inches and 11.5 inches for
2.times.12's. Similarly the length of the two bottom side webs will
be between 5.5 inches and 0.5 inches for 2.times.6's; 7.5 inches
and 0.5 inches for 2.times.8's; 9.5 inches and 0.5 inches for
2.times.10's; and 11.5 inches and 0.5 inches for 2.times.12's. It
will be appreciated by someone skilled in the art that the relative
lengths of the top side webs and bottom side webs may be chosen to
accommodate in situ considerations.
[0055] As discussed above the protective joist cover of the present
invention is made from thermoplastic material. The thermoplastic
may be virgin resin, recycled resin or a mixture of the two. In
addition, the thermoplastic material may contain filler or a
combination of different fillers. A wide variety of fillers may be
used and the filler chosen would depend on the properties desired,
the availability of the different fillers and economic
considerations. For example the filler may be glass fibers, carbon
fibers, metallic fibers, thermoplastic fibers or a combination
thereof. Alternatively the filler may be cellulosic fibers or
particles derived by the comminution or attrition by grinding or
milling of wood, plant matter or agricultural byproducts such as
hulls, husks, shells and straws, or mixtures thereof. As a further
alternative the filler may include cellulosic fibers from recycling
or a byproduct of paper production. As a still further alternative
the filler may be a mineral filler such as talc, mica, calcium
carbonate or clays.
[0056] As used herein, the terms "comprises" and "comprising" are
to be construed as being inclusive and opened rather than
exclusive. Specifically, when used in this specification including
the claims, the terms "comprises" and "comprising" and variations
thereof mean that the specified features, steps or components are
included. The terms are not to be interpreted to exclude the
presence of other features, steps or components.
[0057] It is to be understood that while certain embodiments of
this invention have been described above, the invention is not to
be limited to the specific embodiments shown and described. It will
be apparent to those skilled in the art that various changes may be
made without departing from the scope of the invention and the
invention is not to be considered limited to what is shown in the
drawings and described in the specification.
* * * * *