U.S. patent application number 11/322312 was filed with the patent office on 2007-07-05 for plywood board for concrete form edges.
This patent application is currently assigned to ATLAS CONSTRUCTION SUPPLY, INC.. Invention is credited to James E. Wright.
Application Number | 20070151187 11/322312 |
Document ID | / |
Family ID | 38222894 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070151187 |
Kind Code |
A1 |
Wright; James E. |
July 5, 2007 |
Plywood board for concrete form edges
Abstract
A reusable laminated plywood board, specifically engineered for
forming the edges of poured concrete slabs and tilt-up walls, uses
in each layer a patchwork quadrangular sheets made of solid
fragments of a wood species characterized by a high
strength-to-weight ratio.
Inventors: |
Wright; James E.; (Potrero,
CA) |
Correspondence
Address: |
CHARMASSON, BUCHACA & LEACH, LLP
1545 HOTEL CIRCLE SOUTH, SUITE 150
SAN DIEGO
CA
92108-3426
US
|
Assignee: |
ATLAS CONSTRUCTION SUPPLY,
INC.
|
Family ID: |
38222894 |
Appl. No.: |
11/322312 |
Filed: |
December 31, 2005 |
Current U.S.
Class: |
52/480 |
Current CPC
Class: |
E04G 9/04 20130101; E04G
13/02 20130101 |
Class at
Publication: |
052/480 |
International
Class: |
E04B 9/00 20060101
E04B009/00 |
Claims
1. A plywood board for use in edging poured concrete forms, which
comprises: first and second laminated layers, each of said layers
including a patchwork of sheets peripherally connected to one
another by finger-joints.
2. The board of claim 1 wherein each of said sheets consists of a
solid fragment of wood.
3. The board of claim 1 wherein said wood consist of a sole
species.
4. The board of claim 3 wherein said species is selected from a
group consisting essentially of wood species having a
strength-to-weight ratio, s/g of at least 1.000 wherein s is
expressed in kilograms by cubic inch and g is the specific gravity
defined as the oven-dry weight over the green volume.
5. The board of claim 1 wherein said species consists of Paulownia
wood.
6. The board of claim 4 which further comprises a water repellant
adhesive bonding said layers.
7. The board of claim 4 which further comprises an emulsion PVAc
exterior adhesive joining said sheets.
8. The board of claim 1 wherein said sheets have grains running in
a common direction.
9. The board of claim 8 which further comprises a third of said
layers sandwiched between said first and second layers.
10. The board of claim 9 wherein sheets in said third layers have
grains running orthogonally to said common direction.
11. The board of claim 10 which further comprises a water-repellent
adhesive joining said layers.
12. The board of claim 1 wherein said sheets are quadrangular.
13. The board of claim 12 wherein said sheets have various
sizes.
14. The board of claim 1 wherein said sheets are arranged in
latitudinal rows of sheets having equal lengths.
15. The board of claim 14 wherein said rows in said first sheet are
not aligned with rows in said second sheet.
16. The board of claim 10 wherein said sheets are arranged in
longitudinal columns of sheets having the same widths.
Description
FIELD OF THE INVENTION
[0001] This invention relates to lumbers products and more
particularly to engineered plywood panels used in the construction
of concrete forms.
BACKGROUND OF THE INVENTION
[0002] When pouring concrete slabs, tilt-up walls and other flat
structures, the peripheral edges of the forms are commonly
constructed with various types of milled lumber components such as
planks or beams which are often discarded after the forms are
broken down.
[0003] Plywood panels used in the construction of concrete forms
are commonly engineered in several laminated plies or layers of
diverse woods. The layers are dried and joined under pressure with
glue. The grain of successive layers are alternated in order to
equalize strain and minimize shrinkage and warping. More recently,
panels are also made of fragmented and scattered wood chips pressed
together after being saturated with glue. The instant invention
result from an attempt to apply some of the technology developed in
connection with construction plywood to the manufacture of edging
forms that define the perimeter of poured concrete structures.
SUMMARY OF THE INVENTION
[0004] This invention yields an engineered concrete plywood board
that can be reused a number of times. The board is strong, but
relatively inexpensive due to the use of wood sheets that are
peripherally finger-joined to one another within each layer or ply
with a PVAc exterior adhesive. The sheets are of unequal sizes, but
arranged in rows or columns of a constant height so that joint
lines are not aligned between layers. The layers are laminated with
a water-repellent adhesive. Each sheet is made from a solid
rectangular fragment of wood, and are all made of a single species
selected for its high strength-to-weight ratio.
[0005] In a first embodiment of the invention, the board consists
of only two layers in which the grains of all sheets run in the
same direction. In an alternate embodiment a third sheet is
sandwiched between two external ones with the grain running in a
direction orthogonal to the grain in the other sheets.
BRIEF DESCRIPTION OF THE DRAWING
[0006] FIG. 1 is a perspective view of a preferred embodiment of
the plywood board according to the invention;
[0007] FIG. 2 is a detailed perspective view of a segment of the
board of FIG. 1; and
[0008] FIG. 3 is an exploded view of the board.
DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
[0009] Referring now to the drawing, there is shown an engineered
plywood board 1made of three layers 2,3,4 laminated under pressure,
and secured together by a water-repellent exterior adhesive.
[0010] The board has dimensions of 1.20 by 4.80 meters (4 by 16
feet) and a thickness T of approximately 3.175 centimeters (1.25
inch). It must be understood that other overall dimensions and
thicknesses can be used within the scope of the invention.
[0011] The exterior layers 2,4 are essentially similar, each made
of a patchwork of solid wood sheets 5 that are attached to one
another around each sheet's periphery by finger-joints 6. The
finger joints use an emulsion PAVc exterior adhesive.
[0012] The sheets 5 have different dimensions, but, in the exterior
layers they are arranged in latitudinal (running across the longest
dimension of the board) rows 7 of a constant height H, the sheets
having all the same length and a variety of widths. In the middle
layer 3, the sheets are arranged in longitudinal (running with the
longest dimension of the board) columns 8 of constant width W. Rows
between the respective external layers do not line up so that the
joint-finger seams or lines do not either.
[0013] Each sheet 5 consists of a single solid wood fragment having
a thickness of approximately 10.58 millimeters (0.417 inch) or
15.875 millimeters (0.625 inch). The length and width varies from a
few centimeters to about 50 centimeters (20 inches).
[0014] The species of wood is selected for its high
strength-to-weight ratio of no less than 1.000 where the strength
is defined in kilograms per cubic meter, and the weight as the
specific gravity, meaning the ratio of oven-dry weight over the
green volume.
[0015] Preferably, the sheets are made of Paulownia wood, or other
high strength-to-weight ratio species.
[0016] The edge 9 is sealed with an oily composition to prevent
drying or a release agent.
[0017] The 10.58 millimeter thick board exhibits the following
characteristics:
[0018] Weight: 56.35 kilograms (124 lbs.)
[0019] Tensile strength: More than 372 atmospheres (5,740 psi)
[0020] Average number of uses without significant deterioration:
50
[0021] An alternate and lighter version of the board may be
manufactured by omitting the middle layer 3. The sheet patchwork
design is deemed sufficient to assure adequate strength in spite of
the two layers having the same grain orientation.
[0022] While the preferred embodiment of the invention has been
described, modification can be made to it and other embodiments may
be devised within the spirit of the invention and the scope of the
appended claims.
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