Note: Descriptions are shown in the official language in which they were submitted.
CA 02218237 1997-10-14
TITLE: ARTICLES WITH TONGUE AND GROOVE JOINT AND METHOD
OF MAKING SUC~ A JOINT
INVENTOR: THOMAS J. NELSON
BACKGROUND OF THE !NVENTION
1. Field of the Invention
This invention relates to tongue and groove joints. These joints are particularty
useful for joining pieces of laminate flooring. Glue in these joints resists pen~ lio" of
moisture.
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2. neS~ JtiGI I of the Rei~ted Art
Commercially available laminate flooring generally includes a wear surface gluedto a s~,bstrate. The wear surface generally is high-wear resistant decorative laminate.
The substrate generally is fiber board or particle board. Each piece of laminate flooring
generally has a groove along one end and one side suitable for joining with a tongue
20 along one side or end of an adjacent piece of laminate flooring.
While such laminate flooring has found wide acceptance in Europe as flooring, itis not substantial~ used in the United States. In part the reason may be due to
inst~llation difficulties and the lack of moisture resistance in the joint areas.
Laminate flooring is assembled by placing glue in the groove and inserting the
tongue of one piece into the groove of an ~jacent piece. A su~,st~ Itially
complementa~ fit of a tongue and groove results in difficu~ty in aligning the tongue and
groove. Additionally, as the glue is absorbed into substrate, the substrate swells.
30 causing the groove to tightly squee~e the tongue. This can make full insertion of the
tongue into the groove extremely difficult. Furthermore, as the tongue and groove are
moved together, glue can be compressed in the groove by the tongue in a piston
fashion. This can increase the difficulty in abutting the wear surfaces of ~ entlaminate flooring pieces.
To overcome this assembly problem, laminate flooring manufactures offer
E~ress Mail No. HB105783865 March 22,1995 1 Docket No. 130129-045
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special tools for assembling pieces of laminate flooring.
One such special tool is a hammering aid that has a flat curface and
complementary tongue and groove engaging surfaces. When difficulty is encountered
in abutting the wear surfaces of adjacent pieces, the hammering aid is placed along the
edge of the laminate. The flat surface of the hammering aid is then struck with a
hammer repeatedly to apply a force to the joint and force the tongue and groove
together.
However, even with the use of a hammering aid, a gap can remain ~ ccn
adjacent pieces. The gap is unsight~ and allows for damaging penetr~lion of moisture
to the su~ te. The problem with moisture p~"et~alion into the joint is that it can
c.ause the substrate to swell. F~cess swelling damages laminate flooring.
lS Laminate flooring with tongue and groove joints are difficult to manufacture. The
tight complementary fit l,e~Y~ccn the tongue and groove requires dltentio" be paid to
cutting tolerances for the widths of the tongue and groove. An inleresli.,y yet
le, nalic phenomenon occurs during the process of cutting the tongues and
grooves. The cutting process itself proglessively dulls and wears the cutting bl~es
As the bl~ties pr~g,essively wear, grooves of later c~lt articles are pr~g~ssively
narrower than grooves of earlier cut articles. Likewise, tongues of later cut articles are
progressive~ wider than tongues of earlier cut articles. Unfortunately, at some point,
the widths of the tongues and grooves are not within acceptable tolerances.
Thus there is a need in the art for an improved tongue and grooved joint. There
is a need for a tongue and groove joint that does not require special tools for
inst~ tion. There is a need for a moisture resistant tongue and groove joint. These
and other needs will become apparent to those of skill in the art upon review of this
specification, including its claims and drawings.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide for an improved tongue and
grooved joint.
3S
It is even another object of the present invention to provide for a tongue and
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grooved joint that does not require special tools for installation.
It is yet another object of the present invention to provide ~or a moisture resistant
tongue and groove joint.
These and other objects of the present invention will become apparent to those
of skill in the art upon review of this specification including its claims and drawings.
An article of the present invention has a planar decorative wear surface a
o grooved edge and a tongued edge. The tongued edge has a tongue with a planar
lower surface positioned an index distance from and parallel to the planar decorative
surface. The grooved surface has a groove with a planar lower surface positioned the
- index distance from and parallel to the planar decorative surface. The upper surfaces
of the tongue and groove are shaped and sked such that upon joining two pieces of the
article by positio"ing the lower surfaces of the tongues and grooves to~tt,er and
moving the tongue of one piece into the groove of another piec~ liquid glue p~aced in
the groove will be squeezed out between the upper surfaces of the tongue and groove
and upwardly ~ cn the tongued and grooved edge toward the decorative surfaces
of the two pieces. This joint can be assembled without the use of special tools and the
20 glue acts as a barrier to water damage to substrate ot laminate flooring.
The tongue has a beveled surface extending from the end surface to the upper
surface of the tongue. The beveled surface can form an oblique angle to the upper
surface of the tongue. Preferably more than about one hatf and most preferably more
than about two thirds of ttle length of upper surface of the tongue remains after the
beveled surface is cut. A space for glue to be squeezed through is provided l~tr/ecn
the upper surfaces of tongues and grooves upon joining pieces of the article. A space
for glue to be squeezed through is also provided between a planar surface above the
tongue and a planar surface above the groove. The planar surface above the tongue
30 forrns a right angle to the decorative surface. The planar surface above the groove
forms an acute angle to the decorative surface The acute angle can be about 82.5 to
87.5 degrees. A space is provided between a planar surface below the tongue and a
planar surface below the groove. The planar surface below the tongue forms a right
angle to the decorative surface. The planar surface below the groove forms an acute
35 angle to the decorative surface The acute angle can be about 82.~ to 87.~ degrees.
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BRIFF DFSCRIPTION OF THE DRAWINGS
Figure 1 is a side-view of the tongue and groove joint of the present invention.
Figure 2 is a side-view of an assembly step of the tongue and groove joint of the
present invention showing glue placed in the groove and the tongue entering the
groove.
Figure 3 is a side-view of an assemb~ step of the tongue and groove joint of thepresent invention showing the tongue in contact with glue in the groove and the glue
being squeezed out.
- Figure 4 is a side-view showing the tongue and groove of the present invention
being fully joined and glue squeezed out to the wear surface.
hgures 5 - 8 show the dimensions of an embodiment of the tongue and groove
joint cf the present invention in English and Metric units.
I )FTAII Fn DF~CRIPTION OF THF INVENTION
The tongue and groove joint of the present invent,ol~ is described with refer~nce
to laminate flooring. However, the prese"l invention is applicable to other articles that
can be joined with tongue and groove joints.
2S Features and functions of the tongue and groove joint of the present invention
are shown in side views of pieces of laminate flooring 10 on figures 1 - 4. A piece of
laminate flooring 10 is shown on figure 1 with a rectangular tongue 26 on a planar
tongued edge 25. Another piece of laminate flooring 10 is shown on figure 1 with a
rectangular groove 16 on a planar grooved edge 15.
Additional features of laminate flooring are decoralive laminate 11, sub:jlrate 13,
and backer 14. The decorative laminate provides a wear surface 12. The tongue 26and groove 16 are cut in the substrate. It is believed that particle board, fiberboard or
plywood can be suitable substrates 13 for laminate flooring. A backer 14 is believed to
be required when laminate tlooring is to be installed on a flexible pad. The backer 14
provides dimensional stability to the laminate flooring and can be a moisture barrier. It
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is believed that a backer is not required for laminate Slooring that will be glued to an
existing floor.
The tongue 26 and groove 16 are shown on figure 1 as having planar lower
s surfaces, 28 and 18 respectively. These planar lower surfaces are parallel with and an
indexing distance from planar wear surface 12. Abutment of the planar lower surface
28 of tongue 26 and the planar lower surface 18 of groove 16 during the joining of the
tongue and groove, as shown on figures 2 through 4, causes indexing of wear surfaces
12 of pieces of laminate flooring 10.
The tongue 26 and groove 16 are shown on figures 3 and 4 as having planar
upper surfaces, 27 and 17 respectively. These planar upper surfaces are parallel and
- spaced apart. This space provides a flow path for glue to flow during the joining of the
tongue and groove joint of this invention.
The planar tongued and grooved edges, 25 and 15 respectively, above and
below the tongue 26 and groove 16 are shown on figure 4 as not being parallel. The
planar tongued edge 25 is cut at a right angle (90 degrees) to the wear surface. The
planar grooved edge 15 is cut at an acute angle (less than 90 dsgrees) to the wear
20 surface. This provides a space above tongue 26 and groove 16 for glue 20 to flow to
the wear surface 12 of laminate flooring 10. It is believed that this acute angle should
be about 82.5 to 87.5 degrees. An acute angle above about 87.5 degrees will not
provide sufficient space for viscous glue to flow to the wear surface 12. An acute angle
of less than about 82.5 degrees will resu~t in a iarger space than required. Water
absorbed by the substrate from the e,~cess glue could swell the su~s~rate and separate
the planar tongued and grooved edges, 25 and 15 respectively. This also provides a
space below the tongue 26 and groove 16 for the substrate to absorb moisture andswell without damaging the laminate flooring. It is believed that this swelling will not
apply pressure for separating the planar tongued and grooved edges, 25 and 15
30 respectively.
Tongue 26 is shown as having a beveled surface 30 extending from its end
surface 29 to its upper surface 27. The bevel is shown as cut at an oblique (45 degree)
angle to the upper 27 and end 29 surfaces of the tongue 26. The beveled surface 30
35 can serve as a guide during the joining of tongue 26 and groove 16.
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Glue 20 is shown on figure 2 in the end 19 of groove 16. Glue 20, after curing,
adheres the tongue and groove joint together and acts as a barrier against moisture
penetration to the substrate 13. Commercially available wood glues are suitable to
adhere the tongue and groove joint together. Franklin Titebond ll Wood Glue, which is
s available from Franklin Intemational of Columbus, Ohio is believed to be suitable for
joining laminate flooring. Franklin Titebond ll Wood Glue is believed to be a polyvinyi
acetate emulsion adhesive. When laminate flooring is installed on a flexible pad, it is
believed to be desirable for the glue to be somewhat llexible. It is thought that fleYibility
of the glue, after curing, can better accommodate depression of laminate flooring at the
10 tongue and groove joint of this invention.
Additional features and functions of the tongue and groove joint of this invention
- are shown on figures 2 through 4. As the tongue and groove of two pieces of laminate
flooring 1 0 are joined, tongue 26 applies pressure to liquid glue 20 in groove 16. Glue
20 flows past bev~l~ edge 30 and through space 31 b~Y~s~l the upper surface 27 of
tongue 26 and the upper surface 1 7 of grooYe 1 6. The lower surfaces 28 of tongue 26
and the lower surface 18 of groove 16 are ~h~tte~ thereby providing an impediment to
glue flowing ~t~l~cn the lower surfaces 28 and 18 of the tongue and groove.
The beveled surface 30, as shown of figure 4, reduces the length of the upper
surface 27 of tongue 26 and the upper surface 17 of groove 16 as compared to thelengths of the surfaces of a rectangular tongue. This is believed to aid in glue 20
flowing, preferentially, between the upper surfaces of tongue 26 and groove 16 during
the joining of pieces of laminate flooring 10. The abutment and length of the lower
surfaces, 28 and 18 respective~, of tongue 26 and groove 1 6 is also believed to aid in
glue 20 flowing, preferentially, between the upper surfaces of tongue 26 and groove 16
during the joining of pieces of laminate ~IOGr;~Y 10. Additionally, it is believed that
pressure created on the glue 20 during the joining of the tongue 26 and groove 16, as
shown on figures ~ and 4, will be trans"lit~eJ, in part, downwardly on upper surface 27
and beveled surface 30 of tongue 26. This pressure can also aid in glue 20 flowing,
preferentially, beh~een the upper surfaces of tongue 26 and groove 16 during thejoining of pieces of laminate flooring 1 0.
The curing of the glue 20 involves the loss of solvent, water in the case of
Franklin Titebond ll Wood Glue, to the subsl~dte 13. Water causes swelling of the
substrate. It is believed necessary to limit the volume of glue 20 that will cure by losing
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water or other solvent to the substrate 13. This is accomplished in the embodiment of
this invention as shown on figures 1 - 4 by limiting the distance between (1) the end 19
of groove 16 and the end 29 of tongue 26, (2) the amount of the tongue ~hat is cut off in
making beveled surface 30, (3) the space 31 between the upper surface 27 of tongue
26 and the upper surface 17 of groove 16 and (4) the space 32 between planar
tongued edge 25 and planar grooved edge 15 above tongue 26 and groove 16,
respectively.
It is believed that swelling of the substrate at the upper surfaces of the tongue
lO and groove, 27 and 17 respecti-~e~, aids in holding the tongue and groove joint of this
invention together. Therefore, it is believed that no more than one hatf and preferably
no more than one third of the upper surface 27 of tongue 26 should be removed inclltting the beveled surface 30 on tongue 26. The space between the upper surfaces of
the tongue and groove should be limited to the space required for glue to preferentially
15 flow to the wear surface 12 when tongue 26 and groove 16 are joined. It is believed
that ex,~ess space can result in damage to laminate flooring. Glue loses water to the
substrate 13 ~ cent space 31 during the curing of the glue. Some swelling is
beneficial for producing a tight tongue and groove joint. However, excess swelling
damages laminate flooring.
Sufficient glue 20 should be placed in the end 19 of the groove 16 such that a
portion of the glue will flow to the wear surface 12 as the tongue and groove joint of this
invention is joined. Addrtional glue is not beneficial and increases the cleanup efforts.
2s A laminate flooring embodiment of the tongue and groove joint of this invention
shown on figures 5 through 8. The dimensions of the features of laminate flooring are
preferred dimensions for the embodiment shown. The tolerances are preferred
tolerances for the embodiment shown. Dimensions and tolerances are shown on
figures 5 and 6 in inches. Dimensions and tolerances shown on figures 7 and 8 in30 millimeters.
The tolerances for cutting the upper and lower surfaces of the tongue and
groove are different. It is shown on figures 5 - 8 that the lower surfaces. 28 and 18
respectively, of the tongues and grooves are cut to be 0.2 + 0.0015 inches (5.083~ ~0.0381 millimeters) from the wear surface 12. The upper surface 27 is cut for the
tongue 26 to have a minimum width of 0.09 inches (2.286 millimeters) and to increase
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in width by up to 0.003 inches (0.0762 millimeters) during the cutting of the tongue.
The upper surface 17 is cut for the groove to have a maximum width of 0.1 inches (2.54
millimeters) and to decrease in width by up to 0.~03 inches (0.0762 millimeters) during
the cutting of the groove. This provides a minimum space 31 between the upper
surface 27 of tongue 26 and the upper surface 17 of groove 16 of 0.004 inches (0.1016
millimeters).
While the illustrative embodiments of the invention have been described with
particularity, it will be understood that various other modifications will be apparent to
0 and can be readily made by those skilled in the art without departing from the spirit and
scope of the invention. Accordingly, it is not intended that the scope of the claims
appended hereto be limited to the examples and descriptions set forth herein but rather
that the claims be construed as encompassing all the features of patentable novelty
that reside in the present invention, including all features that would be treated as
5 equivalents thereof by those skilled the art to which this invention pertains.
Additionally, while the present invention has been illustrated with respect to
laminate flooring, it is to be unJers~ood that the tongue and groove of the present
invention may be utilized in any ~pplic~tion in which ~It is desired to have a tongue and
20 groove joint, including but not limited to flooring in general, fumiture, cabinets,
countertops and wall paneling.
