Note: Descriptions are shown in the official language in which they were submitted.
CA 02338367 2004-04-07
Description
Joint
The invention relates to a joint for structural members, in particular for
floor
panels .
Such a joint for floor panels is for instance disclosed in EP 0 098 162 B1. In
the case of this known, so-called "glue-free" joint, the adjacent
circumferential edges
of the panels are joined by a groove and tongue joint. There, the lower groove
cheek
of the one panel facing the contact face is extended beyond the vertical
parting
plane and comprises a locking projection at its end portion, said locking
projection
immersing in a corresponding recess of the tongue of the other floor panel. In
order
to facilitate the laying of the panels, the joint in the engaging portion of
the extended
groove cheek with the tongue is performed with play so that displacing of the
panel
along the longitudinal edges is rendered possible.
W097147834 A'I shows a generic joint in which, similar to the solution
described above, the lower groove cheek of a floor panel is extended beyond
the
vertical parting plane and is provided with a projection which engages with a
corresponding clamping recess of the tongue. Contrary to the solution
initially
described, the engagement between the extended groove cheek and the
corresponding recess of the tongue is performed such that a force is exerted
by this
locking which presses the two floor panels towards each other perpendicular to
the
vertical plane.
In both solutions described above, the groove and tongue joint has a double
function. The groove and tongue joint on the one hand ensures the accurately
fitting
positioning of the two floor panels relative to each other so that no gaps and
projections occur and the required laying quality is guaranteed. The second
function
consists in ensuring this predetermined relative position by the non-positive
or
positive locking between the extended groove cheek and the tongue even in the
case of strain on the floor or of temperature and moisture fluctuations.
It is a problem With the known solutions that the extended groove cheek has
to be resiliently deformed to perform the engagement between the locking
elements.
In the case of unfavourable conditions, for instance with excessive strain of
the
resilient lower groove cheek or in the case of swelling due to moisture and
the
CA 02338367 2004-04-07
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influence of temperature, cracks may occur in the contact area of the lower
groove
cheek with the pertinent floor panel so that the groove cheek can no longer
fulfil the
locking function described before. In addition, the quality of the fitting of
the groove
and tongue joint is aggravated in the case of such cracks occurring in the
contact
area, so that the accuracy required for correct floor laying is no longer
guaranteed.
As compared to this, it is an object of the present invention to provide a
joint
for structural members, in particular floor panels, in which an accurately
fitting
relative position is ensured with a minimum of equipment required.
Pursuant to the invention, fitting and locking are assumed by two separate
structural members. Fitting is performed conventionally via a groove and
tongue joint
while locking is performed via a twistlock formed at a distance to the groove
and
tongue joint and thus being functionally independent thereof. The twistlock
may be
formed at the tongue-side front face or at the groove-side front face of a
floor panel.
In a preferred embodiment, the twistlock is formed at a distance to the tongue
and immerses in a recess at the lower, floor-side groove cheek which, contrary
to the
prior art, is not resilient. This means that in a preferred variant both the
tongue and
the twistlock ace passing ttie vertical parting plane between the structural
members
in horizontal direction and are each immersing in corresponding recesses of
the
opposite structural member. With this variant, it is of particular advantage
that
substantially less material has to be removed relative to the solutions
initially
described, so that the shaping process for processing the front faces is
facilitated.
A particularly reliable locking which is easy to be manufactured is obtained
when the twistlock is provided with a recess with which a projection at the
bottom of
the lower groove cheek engages. The contact area between groove cheek and
twistlock is preferably designed as inclined face, so that, even with
relatively great
tolerances, the applying of a predetermined prestress force admitting the two
structural members to move towards each other is ensured.
The twistlock advantageously extends along the lower side of the structural
member, so that a high-quality visible and stepping surface can be produced.
It is of very particular advantage if a groove is formed between the twistlock
and the tongue, the depth of which determines the resilience of the twistlock
relative
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to the vertical parting plane. This means that the tension forces applied by
the
twistlock and the extraction forces for taking apart the structural members
can easily
be adapted to varying ambience conditions or materials by changing the depth
of
this groove.
The invention may for instance be used with laminate floors having a carrier
plate of high-pressure or medium-pressure wood fibers. On principle, the glue-
free
joint pursuant to the invention may also be used with other floors, for
instance
parquet floors.
Another advantage of the joint pursuant to the invention consists in that the
structural members can be joined and locked with each other by sliding along
the
floor face. In the case of the prior art initially mentioned it is, however,
necessary to
first of all incline one structural member relative to the other structural
member so as
to insert the tongue in the groove, and to subsequently cause locking by
twisting to
the plane position. This means that by providing floor panels with the locking
pursuant to the invention the laying of the floor can be performed in a
substantially
easier and quicker Way.
The sliding faces along which the structural members are sliding during the
locking process are preferably designed as inclined faces.
When the structural members are laid flatly side by side, preferably both the
longitudinal edges and the side edges of the structural members are joined
pursuant
to the invention.
In addition to the locking described before, the structural members may also
be glued.
In the following, a preferred embodiment of the invention is explained in
detail
by rneans of schematic drawings.
Fig. 1 illustrates the joint area of two floor panels;
Fig. 2 illustrates the flUOf panels of Fig. 1 in the joined state and
Fig. 3 illustrates a representation to explain the laying process.
CA 02338367 2001-O1-22
The invention will be explained in the following by means of a laminate floor.
Such a laminate floor consists of a plurality of floor members of which merely
the joint area of two adjacent floor panels 2, 4 is illustrated in Fig. 1.
Each floor panel
2, 4 of a laminate floor has a carrier plate 6 - also referred to as core -
consisting of
high-pressure wood fibers. Such a carrier plate 6 ensures good dimensional
stability
and high resistance to pressure.
The floor face of each floor panel 2, 4 is formed by a countermove laminate 8
applied to the lower overall surface of each floor panel. In the case of
particular
applications, a moisture insulating sheet (not illustrated) rnay be
incorporated. This
countermove laminate 8 further increases the dimensional stability of the
flooring
material. As is illustrated in dot and dash in Figure 1, a dead-sounding layer
11 for
insulating structure-borne noise may be applied at the bottom of each floor
panel 2,
4. The dead-sounding layer may be formed of conventional insulating materials,
such as for instance polyurethane foam etc.
Ttie visible surface of the floor panels 2, 4 is formed by a decorating
laminate
and a cover layer 12 applied thereupon. The decorating laminate 10 is
manufactured by printing and gives the floor an appearance that comes
extremely
close to the structure of natural wood floors. The cover layer 12 provides for
the
necessary robustness and wear resistance of the flooring material.
In the front face 14 of the floor panel 4 illustrated in Fig. 1, a rectangular
groove 16 is formed which is limited by a higher groove cheek 18 and a lower
groove
cheek 20.
The lower portion of tf~e groove cheek 20 which is spaced apart from the
groove 16 is provided with a recess 22, the depth T of which his greater than
the
depth t of the groove 16. The remaining wall thickness of the groove cheek 20
is so
great that its resilient deformation during the joint of the panel is
practically
negligible. At the lower side of the groove cheek 20 a projection 24 is
provided which
extends in the direction of the floor face of the floor panel 4. The side
faces
(perpendicular to the drawing plane) of the projection 24 are fon~ed by
inclined
faces.
The front face 26 of the adjacent floor panel 2 is of corresponding
construction. Accordingly, a tongue 28 corresponding to the groove 16 projects
from
the front face 26. The groove and tongue joint formed by the groove 16 and the
CA 02338367 2001-O1-22
tongue 28 corresponds to the joint of conventional laminate floors which are,
for
instance, joined by gluing only. In the area of the floor face of the floor
panel 2, a
twistlock 30 is formed which is separated from the tongue 28 via a front
recess 32.
This means that the side walls of the front recess 32 are on the one hand
limited by
the twistlock 30 and on the other hand by the tongue 28. The depth S of the
front
recess 32 is greater than the length s of the twistlock - i.e. the groove
bottom is
displaced inwardly relative to the front face 26. By varying the depth S, the
resilience
of the twistlock 30 can be adjusted so that the extraction forces for
dismounting the
floor can be adapted.
The major area of the twistlock 30 which is spaced apart from the front recess
32 extends in prolongation of the floor face of the floor panel 2. In the face
of the
twistlock 30 facing the front recess 32, a notch 34 is provided which - as
will be
described in detail in the following - is engageable with the projection 24 of
the
recess 22 and is formed approximately below the front face of the tongue 28.
The front face of the twistlock 30 is provided with an inclined sliding face
36
which facilitates the joint of the floor panels 2, 4 in interaction with the
adjacent
inclined face of the projection 24.
For joint the floor panels 2, 4, the projection 24 slides on the sliding face
36
and the tongue 28 immerses in the groove 16. In this relative position, the
lower
groove cheek 20 in turn immerses in the front recess 32.
On further shifting of the floor panel 4 relative to the floor panel 2, the
twistlock 30 is resiliently deflected downwards due to the transversal force
introduced via the inclined sliding face 36 (cf. Fig. 2, illustration in dot
and dash).
The sliding face 36 slides along the projection 24 until the latter catches
with the
notch 34. In this state, the twistlock 30 engages the projection 24, the
contact
between these two structural members merely being performed along the inclined
faces formed at the right side in Fig. 2 while the inclined faces positioned
at the left
side are spaced apart from each other.
The position of the projection 24 and of the notch 32 is chosen such that the
two front faces 14, 26 are flatly pressed against each other in the locked
state, so
that the gap in the front face area between the two floor panels 2, 4 is
minimal. The
front face of the twistlock 30 is spaced apart from the adjacent front face of
the
recess 22. Since the depth S of the front recess 32 is greater than the length
s of the
tongue 28, the bottom of the front recess 32 is also spaced apart from the
front face
CA 02338367 2001-O1-22
~i
14 of the floor panel 4 alleging the parting plane 38 (Fig. 2, illustration in
dot and
dash).
The orientation of the floor panels 2, 4 in vertical direction is performed
alone
by the groove and tongue joint 28, 16, while the locking and pressing of the
floor
panels 2, 4 is performed alone by the twistlock 30 interacting with the
projection 24.
and thus depends on the resilience of the twistlock 30. This can be changed by
varying the depth S of the front recess 32 (indicated by broken lines in Fig.
1 ), so
that the resilient deflection of the twistlock 30 and the locking force can
easily be
adapted as a function of the choice of material and of the conditions of use
of the
floor.
Even if, in the case of unfavourable conditions, for instance with an
overstraining of the twistlock 30, a crack occurs in the area indicated with
reference
numeral 40, no offset in height has to be feared since the fisting between the
groove
16 and the tongue 28 remains unimpaired while at most the locking forces are
reduced.
With the conventional solutions, due to the double function of the groove and
tongue joint, both the locking and the fitting between the floor panels are
neutralized
when the lower groove cheek breaks. The invention thus constitutes a
substantial
improvement of conventional glue-free joints, so that an accurately fitting
laying of
the floor is guaranteed even with highest strains and even in the case of
mistakes in
laying.
The method of laying the floor panels 2, 4 as constructed pursuant to the
invention is explained in the following by means of Figure 3. It is assumed
that one
or several floor panels 2 (4) have already been laid on a floor 42 indicated
with in
dot and dash, wish merely the longitudinal side of the panel incorporating the
tongue
28 and the twistlock 30 being illustrated in Fig. 3. The floor panel 4 to be
added also
is placed flatly on the floor 42 and is then shifted in X-direction (arrow in
Figure 3)
until the inclined face 36 gets into contact with the projection 24.
Subsequently, a
striking block 44 is applied which has a more or less L-shaped cross-section
and
which rests with its longer leg on the upper side of the floor panel 4 while
the shorter
leg at least partially encompasses the right front face of tt~e floor panel in
Figure 3,
so that this short leg is in contact with the tongue 28.
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By slight strokes with a hammer 46 on the striking block 44 in the direction
of
the floor panel 2 already laid, the engagement of the locking elements is
performed
as illustrated in Figure 2.
The orientation in longitudinal direction of the panels subsequently is
performed by applying the striking block 44 to the narrow side. By applying
strokes,
the floor member 4 can be shifted along the longitudinal side of the panels
that have
already been laid, until the narrow sides are locked with each other.
It is essential that the concept pursuant to the invention allows for the
floor
panels 2, 4 to be joined in flat position, i.e. without twisting. Such
twisting was
necessary with the prior art as initially described. The measures pursuant to
the
invention thus substantially facilitate laying, so that laying work may also
be
performed by a non-professional person.
In order to enable a particularly reliable joint of the floor panels 2. 4,
joint by
gluing may be performed in addition to the locking as explained. This gluing
is
preferably effected in the groove and tongue area.
Another particular advantage of ttie construction pursuant to the invention is
that the twistlock 30 is forrned flush at the lower side of the floor panels
2, 4, so that
a flat contact is guaranteed. Since the groove and tongue joint and the
locking are
provided independently of each other, the two floor panels 2, 4 are guided
exactly by
the groove and tongue joint during the locking process already. With the prior
art
initially mentioned, the lower groove cheek which simultaneously forms the
locking
member is resiliently deflected during the locking process, so that the
precise
guiding of the locking process pursuant to the invention is not possible.
Since no twisting is required with the locking pursuant to the invention, it
remains left to the person laying the panels whether he will first join the
long sides or
the narrow sides of the floor panels. In the case of locking which requires
twisting,
the adjacent floor panels first had to be joined along the narrow sides, and
subsequently this long board consisting of a plurality of individual floor
panels had to
be twisted to engage with the floor panel already laid. This is substantially
more
awkward since the aligning of such long boards is much more difficult than the
successive laying of short floor panels.
With the embodiment described before, the twistlock 30 is formed at the same
floor panel 2 as the tongue 28. In kinernatic reversal, the twistlock 30 could
also be
CA 02338367 2001-O1-22
formed at ttie floor panel 4 provided with the groove 16, this, however,
necessitating
the removal of some more material in order to cut the front face free.
Instead of locking via inclined faces, other geometries, for instance rounded
faces, vertical faces, etc. could also be used. It may on principle also be
imagined to
manufacture the twistlock 30 from some other material and to fix it to the
panel.
What is disclosed is a joint for two flat structural members, in particular
floor
panels, wherein a groove and tongue joint is provided functionally separate
from
locking. This locking is effected by a twistlock of a structural member', said
twistlock
being spaced apart from the groove and tongue joint and engaging with a
correspondingly formed engaging element of the other structural member. The
locking is preferably formed both at the longitudinal edges and at the front
edges of
a rectangular structural member, for instance of a floor panel. The locking
allows for
a joint of the floor panels in flat position, i.e. without twisting.
