Title of Invention


Abstract A hollow door of wood material with at least one panel rib (1.12) formed by the joining together of modular components, characterized in that, the modular components are made from scrap wood material, said modular components comprising engagement members, complementary engagement members and connecting means (3.10).
Full Text Field of the Invention
[0001] The present invention relates to hollow door of wood material, [0002] In particular, the present invention relates to a hollow door using modular panel rib components and the method of fabricating the hollow door.
Background of the Invention [0003] At present, hollow doors are constructed primarily of wood or wood composites. Such doors have a frame defining the shape and size of the door with panels or "skins" that form the two fiat vertical sides of the door. [0004] The hollow core of the door has ribs or spacers between the skins to give the door structural strength while keeping the overall weight of the door low.
[0005] The spacers are usually made of a flexible honeycomb of paper or cardboard, glued to the skins of the door.
[0006] While materials used may differ, similar methods of fabrication have also applied to partition panels, signboards, cabinets, writing (white or black) boards, table-tops, floors and ceiling panels, all of which utilize the same construction: that of panels separated by spacers. [0007] One problem with using virgin wood strips as is the cost and weight, in addition, wood is getting scarce. One way to reduce reliance on virgin wood material is to substitute it with paper or cardboard as a spacer material. However, paper and cardboard is susceptible to moisture and dampness.
[0008] Another problem is that significant portion of the cost of the items is due to the manufacturing cost of the paper or cardboard honeycombs as specialized equipment are needed.
[0009] These problems in the current art are especially ironic since carpentry factories and workshops fabricating hollow doors and other furnishings generate a lot of off-cuts or scrap wood. Left unused, this scrap wood is usually disposed of as waste.
Summary of the Invention
[0010] The present invention seeks to provide a method to render scrap
wood or wood composites Into modular components for the manufacture of
wood hollow doors.
[0011] In particular, the present invention teaches methods for the rendering
scrap wood or wood composites into modular components of panel ribs,
elements of the present invention, for the manufacture of hollow wooden
[0012] In another aspect, the present invention is a hollow door fabricated
according to the methods of the present invention.
Brief Description of the Drawings
[0013] A preferred embodiment of the present invention will now be more fuiiy described, by way of example, with reference to the drawings of which: [0014] FIG. 1 illustrates two hollow doors with the panel or "skin" from one side is partially removed to expose the hollow core of the door occupied by a honeycomb of paper one (FIG. 1 A) and a modular latticework made from scrap wood in the other (FIG. 1B);
[0015] FIG. 2 shows the method of making panel ribs from short pieces of scrap wood using notches and connector blocks;
[0016] FIG. 3 shows the method of fastening panel ribs to a connector block in a radial pattern using conventional woodworking festeners; [0017] FIG. 4 shows how panel ribs may be Joined with a notched connector; and
[0018] FIG. 5A, 5B shows two possible lattice arrangements in hollow doors under the present invention
Detailed Description of the Drawings
[0019] In accordance with the present invention, methods of rendering
scrap construction or manufacturing materials, particularly off-cuts from
wood and wood composites Into modular components, and a preferred
embodiment of the Invention, fabrication of a hollow door, are described.
[0020] In the following description, details are provided to describe the
preferred embodiment It shall be apparent to one skilled in the art,
however, that the invention may be practiced without such details. Some of
these details may not be described at length so as not to obscure the
[0021] Here, all reference to wood material also refers to wood composites.
Similarly, references to paper also refer to cardboard. As In the industry,
the panels of the hollow doors are also referred to as 'skins' in the present
[0022] The terms "connector" and 'connector block" are also used
interchangeably In the present invention. Both are used to ]o!n modular
components to form panel ribs.
[0023] One aspect of the present Invention Is a method of rendering scrap
wood into modular components for the assembly of panel ribs. This is done
by making use of various ways to connect the modular components into a
latticework of panel ribs to replace the paper or cardboard honeycomb
between panels of the finished product
[0024] While hollow doors may be made of materials other than wood, the
present invention is directed to the panel ribs of hollow doors and similar
products made of wood and wood composite. However, hollow doors
fabricated of materials other than wood or wood composite but utilizing the
method taught in the present invention are within the scope and spirit of the
present invention.
[0025] There are many advantages of the present invention. One advantage
is that scrap wood may be used as panel ribs. Scrap wood or waste wood
is also called "off-cuts". These are the remnants of wood left over from
furniture manufacturing. They come in odd sizes and are usually of lengths
too short to be useful for other purposes and are usually disposed of as
[0026] This invention teaches methods of rendering these short pieces of
scrap wood into useful components for panel ribs, the invention also
teaches methods to join these components into useful configurations for
use in hollow doors and similar furnishings.
[0027] By advantageously utilizing this hitherto useless material, the need to
dispose of this scrap wood by either burning or dumping is greatly reduced,
allowing the present invention to contribute in reducing impact on the
[0028] Another advantage of the present invention is that wood, especially
wood composite, is more moisture resistant than paper or cardboard.
When used as panel ribs, the final product is more durable in damp or
humid environments.
[0029] Hollow doors made with wood panel ribs are structurally stronger
than those made with paper or cardboard honeycomb.
[0030] While heart of the invention is the Idea of joining modular pieces of
wood into panel ribs, the various methods of joining the strips of wood are
encompassed by the scope of the present invention. Some examples of
joining the wood strips through the use of an engagement member (strip)
and a complementary engagement member (connector) are taught below.
[0031] Referring now to FIG.1A and 1B, a door made with a paper
honeycomb 1.10 is compared with another made with panel ribs 1.12 as
taught in the present invention.
[0032] In FIG. 2, it can be seen that short pieces or strips of wood 2.10 are
joined with complementary notches. These engagement members and
their complementary engagement members are elements of the present
[0033] One way is to join short strips of wood is through the use of
corresponding half notches 2.12 cut into the strips of wood. Multiple strips
of wood may be joined side by side by using notches 2.14 that are
correspondingly as wide as the thickness required.
[0034] While the joining of panel ribs with each other or with connector
blocks are shown as notches 2.12 and 2.14, tongue-and-groove or mortise-
and-tenon type joints (not shown) may also be used.
[0035] Another way to join strips of off-cuts is by the use of connector
blocks (FIG. 3). Such connector blocks may be rectangular, circular or
polygonal in cross-section and be of varying thickness. The use of
connector blocks gives greater latitude to the pattern of latticework possible
and hence greater usage of scrap wood.
[0036] For example, as may be seen in FIG. 3, a hexagonal 3.10 or circular
connector will allow panels ribs to be joined in a radial pattern. In FIG 3, the
strips are joined to connector block 3.10 by means of conventional
woodworking fasteners such as nails 3.12, tacks, screws or angle plates.
[0037] Components described may join at angles to form a "T" joint, an "L"
or "V" joint or a rectangle.
[0038] Connector blocks also allow end-to-end joining of panel ribs to form
a longer strip of wood (FIG. 4). A connector that is notched 4.16 may be
readily joined to both strips with 4.17 or without notches 4.18 at the ends.
Means other than notches, mortise-and-tenon joints may be used to join
these modular components under the present invention.
[0039] The complementary structures of these components cited above
allow these components to be connected without the need for adhesives.
This lowers costs and speeds up production.
[0040] Similarly, instead of using the methods or modular components
described above, the engagement members may also be joined by the
connecting means with conventional woodworking fasteners such as nails,
tacks or screws,
[0041] FIG. 5A and 5B show two arrangements of latticework fabricated
under the scope of the present invention. The panel ribs may be formed
from a mixture of dedicated ribs 5.10 (eg the vertical continuous strips) of
virgin, non-scrap wood, and scrap wood 5.12 (the diagonal ribs) or entirely
of scrap wood 5.14 with the methods of joining described above. FIG. 1B is
an example showing another possible arrangement of latticework under the
present invention.
[0042] Even with the use of some virgin material, scrap wood still forms the
bulk of the present invention, making it extremely environmentally friendly.
[0043] To practise this invention, the method of joining strips with notches is
described as the preferred embodiment Similar fabrication procedures and
a combination of the joining methods, while not described in detail, may
also be used.
[0044] Simple settings of a rip saw fence arrangement shoutd first be
determined and set up. This will generate useful strips of uniform width and
thickness from the scrap wood.
[0045] Then a jig indicating the intervals at which to cut the notches should
be used to determine where the notches should be cut. Although elaborate
jigs may be used for this, a simple marked straight edge may also suffice.
[0046] Strips with notches cut at regular intervals are then rendered from
scrap wood using the above arrangements.
[0047] Thus a ready supply of these modular components of uniformly cut
strips, may be generated for the fabrication of hollow doors.
[0048] A hollow door is assembled as usual with the frame placed over the
skin or panel of one side and this arrangement secured. A latticework of
panel ribs may be assembled in place, in the hollow of the door.
Alternatively, the lattice may be assembled on a schematic of the frame and
then placed in the hollow defined by the frame as a complete component.
[0049] The edges of the panel ribs in contact with the skin are painted with
a suitable adhesive and the panel ribs placed in contact with the skin.
[0050] Again, wood glue or a suitable adhesive applied to the other exposed
narrow edges of the panel ribs. With the use of half notches, the latticework
of scrap wood need not be secured by any adhesive as contact with the
skins of the door will keep them in place.
[0051] The skin of the other side is then place over the hollow such that
both skins contact the adhesive. The skins are then held to the frame and
panel ribs by presses until the glue has cured.
[0052] When the glue or adhesive has dried or cured, the door is trimmed
and finished.
[0053] It will be apparent to anyone of ordinary skill in the art that the
procedure of fabricating a hollow door may be varied significantly without
affecting the finished product or departing from the scope of the present
[0054] Again, it will be appreciated by anyone of ordinary skill in the art that
handling the latticework of panel ribs is significantly easier than a
manipulating a honeycomb of paper or cardboard.
[0055] The present invention is also non-obvious and entailed an inventive
step, as apparent from the lack of prior art teaching the use of rendering
and joining scrap wood strips into usable panel ribs for hollow doors.
[0056] The different latticework of panel ribs may be varied to suit the
requirements of the door. If a stronger door is required, a denser
arrangement of panel ribs with more cross-linked members may be used.
[0057] It will also be appreciated by anyone concerned with the environment
that maximizing the use of scrap wood in the present invention is
environmentally friendly and will reduce the use of virgin material for the
fabrication of hollow doors and products of similar construction.
[00581 While a wood hollow door Is described, it will also be apparent to one
of ordinary skill in the art that the invention may also be practiced in the
fabrication of other furnishings and structures such as hollow partition
panels, cabinets, writing boards, desk and table tops, and signboards, all of
which utilize similar methods of construction and are hence within the scope
of the present invention.
[0059] Various improvements, particularly to methods of joining the panel
ribs together, may also be made without departing from the scope of the
present invention.

1. A hollow door of wood material with at least one panel rib (1.12) formed by the joining together of modular components, characterized in that, the modular components are made from scrap wood material, said modular components comprising engagement members, complementary engagement members and connecting means (3.10).
2. A hollow door as claimed in Claim 1, wherein said joining of said panel rib's (1.12) said engagement members and said complementary engagement members do not require adhesive due to complementary structures of said engagement members and said complementary engagement members.
3. A hollow door as claimed in Claim 1, wherein said panel rib (1.12) comprises modular components of inadequate individual dimensions to form said panel fib (1.12), and wherein joining of said modular components allow panel ribs (1.12) of adequate dimensions to be fabricated.
4. A hollow door as claimed in Claim 1, wherein said engagement members and said complementary engagement members comprise notched components (4.16) for joining one to another.
5. A hollow door as claimed in Claim 1, wherein said connecting means (3.10) comprise fasteners (3.12).
6. A hollow door as claimed in Claim 1, wherein said hollow door comprises a latticework of panel ribs (1.12) formed from modular components, and other components formed from non-scrap wood material.
7. A hollow door as claimed in Claim 6, wherein said latticework is assembled within a frame for a hollow door.
8. A hollow door as claimed in Claim 6, wherein said latticework is pre-
assembled before placing said latticework into a frame for a hollow




2104-delnp-2005-complete specification (as,files).pdf

2104-delnp-2005-complete specification (granted).pdf



2104-delnp-2005-description (complete).pdf














Patent Number 239355
Indian Patent Application Number 2104/DELNP/2005
PG Journal Number 12/2010
Publication Date 19-Mar-2010
Grant Date 16-Mar-2010
Date of Filing 17-May-2005
# Inventor's Name Inventor's Address
PCT International Classification Number E06B 3/74
PCT International Application Number PCT/SG2003/000078
PCT International Filing date 2003-04-11
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 200207576-0 2002-12-16 Singapore