Note: Descriptions are shown in the official language in which they were submitted.
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CA 02433487 2003-07-01 _ ` - -
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FLOORBOARD AND LOGKING SYSTEM THEREFOR
The present invention relates to a locking svstem
for mechanical joinin.g of floorboards and floorboards
having such a locking system.
Technical Field
The invention is particularly suited for floorboards
which are based on wood material and in the normal case
have a core of wood and which are i.ntended to be mecha-
nically joined. The following description of pri,or-art
technique and the objects and features of the invention
will th.erefore be directed at this field of application
and, above all, rectangular parquet floors which are
joined on long side as well as short side. The invention
is particularly suited for floating floora, i.e. floors
that can move in relation to the base. However, it should
=15 be emphasis ed that the invention can be used on all
types of existing hard floors, such as homogen.eous wooden
floors, wooden.floors with a lamellar core or plywood
core, floors with a surface of veneer and a core of wood
f ibre, thin laminate floors, floors with a plasta.c core
and the like. The invention can, of course, also be used
in other types of floorboards which can be machined with
cutting tools, such as subfloors of plywood or particle
board. Even if it is not preferred, the floorboards can
after installation be fixed to the base.
Technical Background of the Invention
Mechanical joints have in a short time taken great
market shares mainly owing to their superior laying pro-
perties, joint strength and joint quality. Even if the
floor according to WO 9426999 as described in more detail
below and the floor marketed under the trademark Alloc
have great advantages compared with traditional, glued
floors, further improvements are, however, desirable.
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Mechanical joint systems are very convenient for
joining not on.ly of laminate floors but also wooden
floors and composite floors. Such floorboards may consist
of a large number of different materials in the surface,
core and rear side. A.s will be described below, these
materials can also be included in the different parts
of the joint system, such as strip, locking element and
tongue. A solution involving an i.ntegrated strip which
is formed according to, for ex.ample, WO 9426999 or
WO 9747834 and which provides the horizontal joi.n.t, and
also involvin.g a tongue which 'provides the vertical
joint, results, however, in costs in the form of material
waste i.n connection with the formingqof the mechanical
joint by machining of the board material.
For optimal function, for instance a 15-mm-thick
parquet floor should have a strip which is of a wl.dth
which is approximately the same as the thickness of the
floor, i,e. about 15 mm. With a ton.gue of about 3 mm,
the amount of waste will be 18 mm. The floorboard has
a normal width of about 200 mm. Therefore the amount of
material waste wi11 be about 9%. Tn general, the cost of
materaal waste will be great if the floorboards consist
of expensive materials, if they are thick or if their
format is small, so that the number of running meters of
joint per square meter of floor wi1_1 be great.
Certainly =Clhe amount of material waste can be reduc-
ed if a strip is used which is'in the form of a separate-
ly man.ufactured aluminium strip which is already fi.xed to
the floorboard at the factory. Moreover, the aluminium
strip can in a number of applications result in a better
and also more inexpensive joint system than a strip
machined and formed from th.e core. However, the alurninium
strip is disadvantageous since the in.vestment cost can be
considerable and extensive reconstruction of the factory
may be necessary to convert an exs.sting traditional pro-
duction line so that floorboards with such a mechanical
joint system can be produced. An advantage of the prior-
i.Si?.
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CA 02433487 2003-07-01
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art aluminium strip is, however, that the starting format
- of the floorboards need not be changed.
When a stri.p produced by machining of the floorboard
material is involved, the reverse is the case. Thus, the
format of the floorboards must be adju.sted so that there
is enota.gh materi.al for formzng the strip and the tongue.
For laminate floors, it is often necessary to change also
the width of the decorative paper used. All these adjust-
ments an.d changes also require costly modi.fications of
production equipment and great product adaptations.
In addition to the above problems relating to
undesirable material waste and costs of production and
product adaptation, the strip has disadvantages in the
form of its bein.g sensitive to damage during transport
and installation.
To sum up, th.ere i.s a great need of providing a
mechanical joint at a lower production cost whi.le at the
same time the aim is to maintain the present excellent
properties as regards laying, taki.ng-up, joint quali.ty
and strength. With prior-art solutions, it is not pos-
sible to obtain a low cost without also having to lower
the standards of strength and/or laying function. An
object of the invention therefore is to indicate solu-
tions which aim at reducing the cost while at the same
time strength and function are retained.
The invention starts from known floorboards which
have a core, a front side, a rear side and opposite joint
edge portions, of which one is formed as a tongue groove
defined by upper and lower lips and having a bottom end,
and the other is formed as a tongue w.ith an upwardly
directed portion at its free outer end. The tongue groove
has the shape of an undercut groove with an opening, an
inner portion and an inner locking surface. At least
parts of the lower lip are formed integrally with the
core of the floorboard and the tongue has a locki.ng sur-
face which is designed to coact with the inner locking
surface in the tongue groove of an adjoining floorboard,
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when two such floorboards are mechanically join.ed, so
~ that their front aides are located in the same surface
plane (HP) a.nd meet at a j oznt plane (VP) d.irected per-
pendicular thereto. This technique is disclosed in inter
alia WO 9627721, DE-A-1212275 and JP 3169967, which will
be discussed in more detail belowo
Defore th.at, however, the general technique regard-
ing floorboards and locking systems for mechanical lock-
ing-together of floorboards will be described as a back-
ground of the present invention.
Description of Prior Art
To facilitate the understandi.ng and description of
the present invention as well as the knowledge of the
problems behind the invention, here follows a descra.ption
of both the basic construction and the function of floor-
boards according to WO 9426999 and WO 9966151, with. refe-
rence to Figs 1-10 in the accompanying drawingse In
applicable parts, the foliowin:g description of the prior-
art techns.que also applies to the ernbodiments of tb.e pre-
sent invention as described belowa
Fi.gs 3a and 3b show a floorboard 1-according to
WO 9426999 from above and from below, respectivelyn The
board 1 is rectangular with an upper side 2, an underside
3, two opposite long sides vaith joint ed.ge porti.ons 4a
and 4b, and two opposite short sides with joint edge por-
tions 5a and 5bo
The joint edge portions 4ag 4b of the long sides as
well as the joint edge portions 5a, 5b of the short sides
can be joined mech.anically without glue in a direction D2
in Figa 1c, so as to meet in a joint plane VP (marked in
Figo 2c) and so as to have, in their lald state, their
upper sides in a common surface plane HP (marked in
Fig 2c) o
Zn the shown embodiment, which is an example of
floorboards according to WO 9426999 (Fi.gs 1-3 in the
accompanying d.rawings), the board 1 has a factory-mounted
plane strip 6 which extends along the en.tire long side
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PCTfSE02/00042
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4a and which is made of a flexible, resilient aluminium
sheet. The strip 6 extends outwards beyond the jo.int
, plane VP at the joint edge portion 4a. The strip 6 can be
attached mechan.ically according to the shown embodiment
or else by glue or i.n sorne other manner. As stated in
said documents, it is possible to use as material for a
stri.p that is attached to the floorboard at the factory,
also other strip materials, such as sheet of some other
metal, aluminium or plastic sections. As is also stated
in WO 9426999 and as described and shown in WO 9966151,
the strip 6 can instead be formed integrally with the
board 1, f or instance by suitable machining of the core
of the board 1.
The present invention i.s usable for floorboards
where the strip or at least part thereof is integrally
formed with the core, and the invention solves special
problems that exist in the joining, disconnection and
production 'of such floorboards. The core of the floor-
board need not, but is preferably, made of a uniform
material. The strip, however, is always integrated with
the board, i.e. it should be formed on the board or be
factory-mounted.
In known embodiments according to the above-mention-
ed WO 9426999 and WO 9966151, the width of the strip 6
can.be about 30 mm and the thickness about 0.5 mm.
A similar, although shorter strip 6' is arranged
along one short si.de 5a of the board 1. The part of the
strip 6 projecting beyond the joint plane VP .is formed
with a locki.ng element 8 which extends along the entire
strip 6. The locking element 8 has in its lower part an
operative locking surface 10 facing the joint plan.e VP
and having a height of, for instance, 0.5 mm. In laying,
this locking surface 10 coacts with a locking groove 14
which is made in the underside 3 of the joint edge por-
tion 4b of the opposite long side of an adjoining board
11 . The strip 6' along the short side is provided with a
corresponding locking element 81, and the joint edge por-
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CA 02433487 2003-07-01
PCT'tSE02100042
10-01-2003
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tion 5b of thz opposite short side has a corresponding
locking groove 14'. The edge of the locking grooves 14.,
14' facing away from the joint plane VP forms an opera-
tive locking surface 10' for coaction with the operati.ve
locking surface 10 of the locking element.
For mechanical joining of long sides as well as
short sides a?so in the vertical direction (direction
Dl in Fig. ic), the board 1 is also along its one long
side (joint edge portion 4a) and its one short sz.de
(joint edge porti.on 5a) formed with a laterally open
recess or tongue groove 16. Th.i.s is defined upwards by an
upper lip at the joint edge portion 4a, 5a an.d downwards
by the respective strips 6, 61. At the opposite edge por-
tions 4b, 5b, there is an upper recess 18 which defines
a lockin.g tongue 20 coacting with th.e recess or tongue
groove 16 (see Fig. 2a) ,
Figs la-lc show how two long sides 4a, 4b of two
such boards l, 1' on a base U can be joined wi.th each
other by downward angling by pivoting about a centre C
close to the intersection between the surface plane HP
and_the joint plane VP, while the boards are held essen-
tially in contact with each other.
Figs 2a-2c show how the short sides 5a, 5b of the
boards 1, 1' can be joined together by snap action. The
long sides 4a, 4b can be joined by means of both methods,
whereas the joining of the short sides 5a, 5b - after
laying of the first row of floorboards - is normally car-
ried ou.t merely by snap action after the long sides 4a,
4b have first been joined.
When a new board 1' and a previously laid board 1
are to be joined along their long si.de edge portsons 4a,
4b according to Figs 1a-lc, the long side edge portion 4b
of the new board 1' is pressed against the long side edge
portion 4a of the previ.ously laid board 1 according to
Fig. 1a, so that the locking tongue 20 is inserted into
the recess or tongue groove 16_ The board 1' is then
angled down towards the subfloor FT according to Fig, 1b.
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10-01-2003
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The locking tongue 20 enters completely the recess or
~ tongue groove 16 while at the same time the locking ele-
ment 8 of th.e strip 6 snaps into the locking groove 14.
During this downward angling, the upper part 9 of the
locking elernent 8 can be operative and perform guiding of
the new board 1' towards the preva.ously laid board 1.
In their joined position according to Fig. 1c, the
boards 1, 1' are certainly locked in the D1 direction as
well as the D2 direction along their long side edge por-
tions 4a, 4b, but the boards l, 1' can be displaced rela-
tive to each other in the longitudinal direction of the
joint along the long sides (i.e. direction D3).
Figs 2a-2c show how the short side edge portions 5a
and 5b of the boards 1, 1' can be joined mechanically in
the D1 as well as the D2 direction by the new board 1'
being displaced essentially horizontally towards the pre-
viously lai.d board 1. This can in particular be carried
out after the long side of the new board 1' has been
joined, by .inward angling according to Figs la-c, with
a previously laid board 1 in an adjoin.ing row. In the
first step in Fig. 2a, bevelled surfaces of the recess
16 and the locking tongue 20 cooperate so that the strip
6' is forced downwards as a direct consequence of the
bringing-together of the short side edge portions 5a, 5b.
During the final bringing-together, the strip 6' snaps up
when the locking element 8' enters the locking groove
141, so that the operative locking surfaces 10, 10' on
the Iocking element 8' and in the locking groove 141
engage each other.
By repeating the operations shown in Figs 1a-c and
2a-c, the entire floor can be laid without glue and along
al1 joint edges. Thus, prior-art floorboards of the above
type can be joined mechanically by first, as a ru1e,
being angled downwards on the long side and by the short
sides, when the long side has been locked, being snapped
together by horizontal displacement of the new board 1'
along the long side of the previously laid board 1
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(direction D3). The boards f, 1' can, wi.thout the joint
- being damaged, be taken up again in reverse order of
laying and then be laid once more. Parts of these laying
principles are applicable also in connection with the
present in.vention.
To function optimally and to allow easy layin.g and
taking-u.p again, the prior-art boards should, after bei,ng
joined, along their long sides be able to take a position
where there is a possibility of a minor play betwee?-~. the
7.0 operative locki.ng surface 10 of the locking element and
the operative locking surface 10' of the locking groove
14. However, no play is necessary in the actu.al butt
joint between ~he boards in the joint plane VP close to
the upper side of the boards (i,e. in the surface plane
1.5 HP). For such a position to be taken, it may be necessary
to press one board against the other. A more detailed
descripti.on of this play is to be found in WO 94269990
Such a play can be in the order of 0~01-0.05 mm between
the operative locking surfaces 10, 10' when pressing the
20 long sides of adjoining boards against each other. This
play facilitates entering of the locking element 8 in the
locking groove 14, 14' and its leaving the same. As men-
tioned., however, no play is required in the joint between
the boards, where the surface plane HP and tra.e joint
25 plane VP intersect at the upper side of the floorboards.
The joint system enables displacement along the
joint edge ~.n the locked position after joining of an
optional side. Therefore laying can take place in~ man.y
different ways which are all variants o.~ the three bas~c
30 methods:
- Angl~,ng of long side and snapping in of short side.
- Snapping in of long side - snapping in of short
side.
- An.gling of sh.ort side, upward anglir~.g of two boards,
35 displacement of the new board along the short side
edge of the prev=ous board and, finally, downward
angling of two boards,
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CA 02433487 2003-07-01
77 PCTlSE02/00042 _
- 10-O1-2003
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' The most comrnon and safest laying method is that the
- long side is first angled downwards and locked against
another floorboard. Subsequently, a displacement in the
locked position takes place towards the short side of
a third floorboard, so that the snapping-in of the short
side,can take place. Laying can also be made by one side,
long side or short side, being snapped together with
another board. Then a displacement in the locked position
takes place until the other side snaps together with a
third board. These two methods require snapping-in of at
least one side. However, laying can also take place with-
out snap action. The third alternative is that the short
side of a first board is angled inwards first towards the
short side of a second board, which i.s already joined on
its long side with a. third board. After this joining-
together, the first and the second board are slightly
angled upwards. The first board is displaced in the
upwardly angled position along its short side until the
upper joint edges of the first and the third board are in
contact with each other, after which the two boards are
jointly angled downwards.
The above-described floorboard and its locking sys-
tem have been very successful on the market in connection
with laminate floors which have a thickness of about 7 mm
and an aluminium strip 6 having a thickness of about
0.6 mm. Similarly, commercial variants of the floorboards
according to WO 9966151 shown i.n Figs 4a and 4b have been
successful. However, it has been found that this tech-
nique is not particularly suited for floorboards that
are made of wood-fibre-based material, especially massive
wood material or glued laminated wood material, to form
parquet floors. One reason why this known technique is
not suited for this type of products is the large amount
of material waste that arises owing to the machining of
the edge portions to form a tongue groove having the
necessary depth.
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One more known design of inechanical locking systems
for boards is shown in GB-A-1430423 and Figs 5a-5b in the
accompanyin.g drawingse This system is basically a tongue-
and-groove joint which is provided with an extra holding
5 hook on an extended lip on one side of the tongue groove
and which has a correspondin.g hold.ing ridge formed on the
upper side of the tongue. The system requires consider-
able elasticity of the lip provided with the hook, and
dismounting cannot take place withou.t destroying the
10 joint edges of the boards< A tight fit makes manufacture
difficul.t and the geometry of the joint causes a large
amount of material waste.
WO 9747834 discloses floorboards wi.th different
types of inechanical locking systems. The locking systems
which are intended for locking together the long sides of
the boards (Figs 2-4 11 and 22-25 in the document) are
design.ed so as to be mounted and disrnounted by a con-
necting and angling movement, while most of th.ose intend-
ed for locking together the short s3des of the boards
(Figs 5-10) are designed so as to be connected to each
other by being translatorily pushed towards each other
for con.nection by means of a snap lock, but these locking
systems at the short sides of the boards cann.ot be dis-
mounted with.out being destroyed or, in any case, damaged.
Some of the boards th.at are di.sclosed in WO 9747834
an.d that have been designed for connection and dismount-
ing either by an angular motion or by snapping together
(F.zgs 2-4 in WO 9747834 and Figs 14a-c in the accompany-
ing drawings), have at their one edge a groove and a
strip projecting below the groove and extending beyond
a joint plan.e where the upper sides of two join.ed boards
meet. The strip is designed to coact with an essenti.ally
complementarily formed portion on the opposite ed.ge of
the board, so that two similar boards can be jo.ined. A
common feature of these floorboards is that the upper
side of the tongue of the boards and the corresponding
upper boundary surface of the groove are plane and ~
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parallel with the upper side or surface of the floor-
boards. The connection of the boards to prevent them from
being pulled apart transversely of the joint plane is
obtained exclusively by means of locking surfaces on the
one hand on the underside of the tongue and, on the other
hand, on the upper side of the lower lip or strip below'
the groove. These locking systems also suffer from the
drawback that they require a strip portion which extends
beyond the joint plane, which causes material waste also
within the joint edge portion where the groove is formed.
For mechani.cal joining of different types of boards,
in particular floorboards, there are many suggestions, in
which the amount of material waste is small and in which
producti.on can take place in an effi.ci.ent manner also
when using wood-fibre- and wood-based board materials.
Thus, WO 9627721 (Figs 5a b in the accompanying drawings)
and JP 3169967 (Figs 7a-b in the accompanying drawings)
disclose two types of snap joints which produce a small
amount of waste but which h.ave the drawback that they
do not allow easy dismounti.ng of the floorboards. More-
over, in these systems it is not possible to use h.igh
locking angles so as to reduce the risk of pulli.ng apart.
Also th.e joint geometry is disadvantageous with regard
to snapping-in, which requires a considerable degree of
material deformation., and with regard to manufacturing
tolerances where large surface portions must be accurate-
ly adjusted to each other. These large surface portions
which are in contact with each other also make a di.s-
pl.acement of the floorboards relative to each other in
the locked position difficult.
Another known system i.s disclosed in. DE-A-1212275
and shown in Figs 8a-b in the accompanying drawings. Thi.s
known system is suited for sports floors of plastic mate-
rial and cannot be manufactured by means of large disk-
shaped cutting tools for forming the sharply undercut
groove. Also this known system cannot be dismounted with-
out the material having so great elasticity that th.e - r!~_!ded b !:= 0
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CA 02433487 2003-07-01
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upper and lower lips round the undercut groove can be
- greatly deformed while bei.ng pulled apart. This type of
joint is therefore not suited for floorboard.s that are
based on wood-based-based material, if high-qualityy
joints are desireda
FR-A-2675174 discloses a mechan.ical joint system for
ceramic tiles which have complementarilv formed opposite
edge portions, in which case use is made of separate
spri.ng clips which are mounted at a distance from each
other and which are formed to grasp a bead on the eage
portion of an adjoining tilee The joint system is not
designed for dismou.nting by pivoting, which is obvious
from Fige l0a and, in particular, Fig. 10b in the accom-
pany.ing drawings.
Another system is disclosed in DE 20001225U1., where
the lower lip yi.eldso This prior-art construction, how-
ever, is very sensitive and has great disadvantages
because the lower lip has been weakened by the locking
groove.
Also DE 19925248 discloses a system wi.th an upwardly
directed locking element.
As is evident from that stated above, prior-art
systems have both drawbacks and a.dvantagesa However, no
locking system is quite suited for rational production
of floorboard.s with a Iocking system which is optimal as
regards production technique, waste of material, laying
and taking-up function and which besides can be used for
floors which are to have high qu.ality, strength and f_unc--
tion in their laid stateo
An object of the present invention is to sat7sfy
this need and provide such an optimal locking system for
floorboards and such optimal floorboardsa Another object
of the invention is to provide a snap joi.nt whi.ch can
be produced in a rational, manner. Further objects of the
invention are evid.ent from that stated above as well as
from the following descri-ptiona
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CA 02433487 2009-05-14
22055-270
13
Summary of the Invention
A floorboard and an openable locking system
therefor comprise an undercut groove on one long side of the
floorboard and a projecting tongue on the opposite long side
of the floorboard. The undercut groove has a corresponding
upwardly directed inner locking surface at a distance from
its tip. The tongue and the undercut groove are formed to
be brought together by snap action. Preferred embodiments
are also dismountable by an angling motion which has its
centre close to the intersection between the surface planes
and the common joint plane of two adjoining floorboards.
The undercut in the tongue groove of such a locking system
can be produced by means of disk-shaped cutting tools whose
rotary shafts are inclined relative to each other to form
first an inner part of the undercut portion of the groove
and then a locking surface positioned closer to the opening
of the groove.
Further advantages and features of the invention
are also evident from the following description.
Before specific and preferred embodiments of the
invention will be described with reference to the
accompanying drawings, the basic concept of the invention
and the strength and function requirements will be
described.
The invention is applicable to rectangular
floorboards having a first pair of parallel sides and a
second pair of parallel sides. With a view to simplifying
the description, the first pair is below referred to as long
sides and the second pair as short sides. It should,
however, be pointed that the invention is also applicable to
boards that can be square.
High Joint Quality
CA 02433487 2003-07-01
- ~v . ntlr:!~,iSJ.:,P PCT'/SE02/00042
i0-O1.-2003
14
By high joint quality is meant a tight fit in the
locked position between the floorboards both verti.cally
and horizontal ly. It should be possible to join the
floorboards without very large visible gaps or diffe-
, 5 rences in leve7: between the joint edges in the unloaded
as well as in the normally loaded state. In a high-
quality floor, joint gaps and differences in level should
not be greater than 0o2 and 0.1 mm respectively.
Upward Angling about Joint Edge
In general, it should be possible to angle the long
side of a floorboard upwards so that the floorboards can
be released. Since the boards in the starting position
are joined with tight joint edges, this upward anglingg
must thus also be able to take place with upper joint
edges in contact with each oth.er and with rotation at the
joint edge. This possibi.lity of upward angling is very
important not only when changing floorboards or moving a
,floor. Many floorboards are trial-laid or laid incorrect-
ly adjacent to doors in corners etc. during installa-'
tion. zt is a serious drawback if the floorboard cannot
be easily released without the joint system bei.ng damag-
ed. Nor is it always the case that a board that can be
an.gled inwards can also be angled up again. In connection
with the downward angling, a slight downwards bending of
the str.ip usually takes place, so that the locking e1e-
ment is bent backwards and downwards and opens. If the
joint system is not formed with'suitable angles and
radii, the board can after laying be locked in such man-
ner that taking-up is not possible. The short side can,
after the joint of the long side has been opened by
upward angling, usually be pulled out along the joint
edge, but it is advantageous i.f also the short side can,
be opened by upward angling. This is parti.cularly advan-
tageous when the boards are long, for instance 2.4 m,
which makes pulling out of short sides di.fficult. The i
upward angling should take place with great safety with-
,
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CA 02433487 2003-07-01
FCTISE02100042
~- - - 10-01-2003
out the boards getting stuck and pinching each other so
as to cause a risk ot the locking system being damaged.
Snapping-in
It should possible to lock the short sides of
floorboards by horizontal snapping-in. Thi.s requires that
parts of the joint system be flexible and bendabl.e. Even
if inward angling of long sides is much easier and
quicker than snapping-in, it is an advantage if also the
long side can be snapped in, sirnce certain layi.ng
operations, for i.nstance round doors, require that the
boards be joined horizontal3y. In case of a snappable
joint, there i.s a risk of edge risi.ng at the joint if the
joint geometry is inappropriate.
Cost of Material at Long and Short Side
zf the floorboard is, for instance, 1.2*0.2 m, each
square meter of floor surface will have about six times
more long side joints than short side joints. A large
amount of rnaterial waste and expensive joint materials
are therefore of less importance on short side than on
long side.
Horizontal Strength
For high strength to be achieved, the locking ele-
ment must as a rule have a high locking angle, so that
the locking element does not snap out. The locking ele-
ment must be h.igh a.nd wide so that it does not break when
subjected to high tensile load as the floor shrinks in
winter owing to the low relative humidity at this time
of the year. This also applies to the material closest
to the locking groove in the other board. The short side
joint should have higher strength than the long side
joint since the tensile load during shrinking in winter
is distributed over a shorter joint length along the
short side than along the long side.
yertical Strength
It should be possible to keep the boards plane when
subjected to vertical loads. Moreover, motion in the
joint should be avoided since surfaces that are subjected
.
t -.
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CA 02433487 2003-07-01
- - ~ PCT1SE02100042
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1 - 1-2003
~. 6
to pressure and that move relatzve to each other, for
instance upper jo.int edges, may cause creaking.
Di.splaceabi.lity
To mak.e it possi.ble to lock all four sides, it must
be possible for a newly laid board to be displaced in
the locked position along a prevs.ously lai.d board. This
should take place using a reasonable amount of force, for
instance by d.ri.ving together using a block and hammer,
without the joint edges being damaged and ws.thout the
joint system having to be formed with visible play hori-
zontally and verticallyo Displaceabi.lity is more zmpor-
tant on long side than on short si.de si.nce the friction
is there essentially greater owing to a longer joint.
Production
Tt should be possible to produce the joint system
rationally using large rotating cutting too3s having
extremely good accuracy and capacity,
Measur.ing
A good function, product3on tolerance and quality
require that the joint profile can be conti.nuously
measured and checked. The critical parts in a mechanical
joint system should be designed in such manner th.at
producti.on and measurement are facilitated. It should be
possible to produce them with tolerances of a few
hundredths of a millimetre, and it should therefore be
possible to measure them with great accuracyP for
i.nstance in a so-called profile projector. If the joint
system is produced with linear cutting machining, the
joint system will, except for certain production
tolerances, have the same profile over the entire edge
portion. Therefore the joint system can be measured with
great accuracy by cutting out some sam.ples by sawing from
the floorboards and measuring them in the profi.le
projector or a measuring microscope. Rational production,
however, requires that the joint system can also be
measured quickly and eass.ly without destructive methods
for instance usi.ng gages. This is facili.tated if the
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CA 02433487 2003-07-01 _
PCT/SE02/00042
, - 10-01-2003
17
critical parts in the locking system are as'few as
possibl.e.
Optimisation of Long and Short Side
For a floorboard to be man.ufactured optimally at a
minimum cost, long and short side should be opti.mised in
view of their different properties as stated above. For
instance, the long side should be optimised for downward
angling, upward angling, positioning and displaceability,
wh.ile the short side should be optimi.sed for snapping-in
and high strength. An optimally designed floorboard
should thus have different joint systems on long and
short side.
Possibility of Moving Transverselv of Join.t Edge
Wood-based floorboards and floorboards in general
which contain wood fibre swell and shrink as the relative
humidity changes. Swelling and shrinking usually start
from above, and the surface layers can therefore move to
a greater exten.t than the core, i.e. the part of which
th.e joint system i.s formed. To prevent the upper joi.nt
edges from rising or being crushed in case of a high
degree of swelling, or joint gaps from arising when
drving up, the joint system should be constructed so as
to allow motion that compensates for swelling and shrink-
ing.
The lnvention
The invention is based on a first understanding
that by usin.g suitable production methods, essentially
by machining and using tools whose tool diameter signi-
ficantly exceeds the th.ickness of the board, it is pos-
sible to form advanced shapes rationally with great accu-
racy of wood materials, wood-based boards and plastic
materials, and that this type of Tnachining can be made
in a tongue groove at a distance from the joint plane.
Thus, the shape of the joint system should be adapted to
rational production which should be able to take place
with very narrow tolerances. Such an adaptation, however,
is not allowed to take place at the expense of other
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CA 02433487 2003-07-01
= a ~i :., _ ----~~I . -__ j '. ~ ~., r"
PCTISE02/00042
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1 - 1-2 03
' 18
important properties of the floorboard and the locking
system.
The inventi.on is also based on a second under-
standin.g, which is based on the knowledge of the require-
ments that must be satisfied by a mechanical joint sys-
tem for optimal function. This understandingg has made it
possible to satisfy these requi.rements in a manner that
has previously not been known, viz. by a combination of
a) the design of the joint system with., for instance,
specifi.c angles, radii, play, free surf aces and ratios
between the different parts of the system, and b} optimal
utilisation of the materi.al properties of the core or
core, such as compression, elongation, bending, tensile
strength and compressive strength,
The invention is further based on a third under-
standing that it is possible to provide a joint system
at a lower production cost wh.i.l.e at the same time func-
tzon and strength can be retained or even, i.n some cases,
be improved by a combination of manufacturing technique,
joint design, choice of materials and optimisation of
long and short sa.des.
The invention is based on a fourth understanding
that the joint system, the manufacturing technique and
the measuring technig,que must be d.eveloped and adjusted
so that the critical parts requiring narrow tolera.nces
shoul.d, to the greatest possible extent, be as few as
possible and also be designed so as to allow measuring
and checking in continuous production.
According to a first aspect of the invention, there
are thus provided a locking system and a floorboard with
such a locking system for mechanical joining of all four
sides of this floorboard in a first vertical directi.on
DI., a second horizontal direction D2 and a third direc-
tion D3 perpendicular to the second horizontal direction,
with corresponding sides of other floorboards with iden-
tical locking systems.
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CA 02433487 2003-07-01
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19
The fl.oorboards can on two sides have a disconnect-
= ible mechan.ical joint system, which is of a known type
and which can be laterally displaced in the locked posi-
tion and locked by inward angling about joint edges or by
horizontal snapping. The floorboards have, on the other
two sides, a lockin.g system according to the invention.
The floorboards can also have a locking system according
to the .invention on all four sides.
At least two opposi.te sides of the floorboard thus
have a joint system which is designed according to the
invention and which comprises a tongue and a tongue
groove defined by upper and lower lips, where the tongue
in its outer and upper part has an upwardly directed part
and where the tongue groove in. its inn.er and upper part
has an undercut. The upwardly directed part of the tongue
.and the undercut of the tongue groove in the upper lip
have locking surfaces that counteract and prevent hori-
zontal separation in a direction D2 transversely of the
joint plar~.e. The tongue and the tongue groove also have
coacting supporting surfaces wh..ich prevent vertical sepa-
ration in a direction Dl parallel with the joint plane.
Such supporting surfaces are to be found at least in the
bottom part of the tongue and on the lower lip of the
tongue groove. In the upper part, the coacting locking
surfaces can serve as upper supporting surfaces, but the
upper 1ip of the tongue groove and the tongue can advan-
tageously also have separate upper supporting surfaces.
The tongue, the tongue groove, the lockin.g element and
the undercut are designed so that they can be manufactur-
ed by machining using tools which have a greater tool
diameter than the thickn.ess of the floorboard. The tongue
can with its upwardly di.rected porti,on be inserted into
the tongue groove and its undercut by essenti.ally hori-
zontal snapping-in, the lower lip being bent so that the
upwardly di.rected portion. of the tongue can. be i.nserted
into the undercut. The lower lip is shorter than the
upper lip, which facilitates the possibility of forming
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CA 02433487 2009-05-14
22055-270
an undercut with a locking surface which has a relatively
high inclination to the surface plane of the board and which
thus gives a high horizontal locking force, which can be
combined with a flexible lower lip.
5 According to a second aspect of the invention, the
floorboard has two edge portions with a joint system
according to the invention, where the tongue with its
upwardly directed portion both can be inserted into the
tongue groove and its undercut by a snap function and can
10 leave the tongue groove by upward angling while at the same
time the boards are kept in contact with each other with
their upper joint edges.
Alternatively or furthermore, the tongue can be
made flexible to facilitate such snapping-in at the short
15 side after the long sides of the floorboard have been
joined. Thus, the invention also relates to a snap joint
which can be released by upward angling with upper joint
edges in contact with each other.
According to a third aspect of the invention, the
20 floorboard has two edge portions with a joint system which
is formed according to the invention, where the tongue,
while the board is held in an upwardly angled position, can
be snapped into the tongue groove and then be angled down by
a pivoting motion about the upper joint edge.
The lower lip is shorter than the upper lip so as
to enable greater degrees of freedom when designing the
undercut of the upper lip and especially its locking
surface.
According to another aspect of the invention, there
is provided a flooring system comprising a plurality of
identical floorboards, which are mechanically joinable at a
CA 02433487 2009-05-14
22055-270
20a
joint plane, said floorboards having a core, a front side, a
rear side and opposite joint edge portions, of which one is
formed as a tongue groove, which is defined by upper and
lower lips and has a bottom end, and the other is formed as a
tongue with an upwardly directed portion at its free outer
end, the tongue groove, seen from the joint plane, having the
shape of an undercut groove with an opening, an inner portion
and an inner locking surface, and at least parts of the lower
lip being formed integrally with the core of the floorboard,
and the tongue having a locking surface which is formed to
coact with the inner locking surface in the tongue groove of
an adjoining floorboard, when two such floorboards are
mechanically joined, so that their front sides are positioned
in the same surface plane and meet at the joint plane
directed perpendicular thereto, wherein the inner locking
surface of the tongue groove is formed on the upper lip
within the undercut portion of the tongue groove for coaction
with the corresponding locking surface of the tongue, said
locking surface being formed on the upwardly directed portion
of the tongue to counteract pulling-apart of two mechanically
joined boards in a direction perpendicular to the joint
plane, wherein the lower lip has a supporting surface for
coaction with a corresponding supporting surface on the
tongue, said supporting surfaces being intended to coact to
counteract a relative displacement of two mechanically joined
boards in a direction perpendicular to the surface plane,
wherein all parts of the portions of the lower lip which are
connected with the core, seen from the point where the
surface plane and the joint plane intersect, are located
outside a plane which is positioned further away from said
point than a locking plane which is parallel therewith and
which is tangent to the coacting locking surfaces of the
tongue groove and the tongue where these are most inclined
relative to the surface plane, wherein the coacting
CA 02433487 2009-05-14
22055-270
20b
supporting surfaces of the lower lip and of the tongue, seen
parallel with the surface plane, are positioned at a distance
from, and closer to the joint plane than to the free outer
end of the tongue, wherein all parts of the portions of the
lower lip which are connected with the core are shorter than
the upper lip and terminate at a distance from the joint
plane, the lower lip is flexible, the upper lip is more rigid
than the lower lip, and the upper and lower lips of the joint
edge portions are formed to enable connection of a laid
floorboard with a new floorboard by a pushing together motion
essentially parallel with the surface plane of the laid
floorboard for snapping together the parts of the locking
system during downward bending of the lower lip of the tongue
groove.
According to another aspect of the invention, there
is provided a floorboard for providing the flooring system as
described herein, by mechanical joining of the floorboard
with similar floorboards at a joint plane between said
floorboard and said adjoining similar floorboard, said
floorboard having a core, a front side, a rear side and
opposite joint edge portions, of which one is formed as a
tongue groove, which is defined by upper and lower lips and
has a bottom end, and the other is formed as a tongue with an
upwardly directed portion at its free outer end, the tongue
groove, seen from the joint plane, having the shape of an
undercut groove with an opening, an inner portion and an
inner locking surface, and at least parts of the lower lip
being formed integrally with the core of the floorboard, and
the tongue having a locking surface which is formed to coact
with the inner locking surface in the tongue groove of said
adjoining floorboard so that their front sides are positioned
in the same surface plane and meet at the joint plane
directed perpendicular thereto, wherein the inner locking
CA 02433487 2009-05-14
22055-270
20c
surface of the tongue groove is formed on the upper lip
within the undercut portion of the tongue groove for coaction
with the corresponding locking surface of the tongue, said
locking surface being formed on the upwardly directed portion
of the tongue to counteract pulling-apart of said two
mechanically joined floorboards in a direction perpendicular
to the joint plane, wherein the lower lip has a supporting
surface for coaction with a corresponding supporting surface
on the tongue, said supporting surfaces being intended to
coact to counteract a relative displacement of said two
mechanically joined floorboards in a direction perpendicular
to the surface plane, wherein all parts of the portions of
the lower lip which are connected with the core, seen from
the point where the surface plane and the joint plane
intersect, are located outside a plane which is positioned
further away from said point than a locking plane which is
parallel therewith and which is tangent to the coacting
locking surfaces of the tongue groove and the tongue where
these are most inclined relative to the surface plane,
wherein the coacting supporting surfaces of the lower lip and
of the tongue, seen parallel with the surface plane, are
positioned at a distance from, and closer to the joint plane
than to the outer free end of the tongue, wherein all parts
of the portions of the lower lip which are connected with the
core are shorter than the upper lip and terminate at a
distance from the joint plane, the lower lip is flexible, the
upper lip is more rigid than the lower lip, and the upper and
lower lips of the joint edge portions are formed to enable
connection of a laid floorboard with said adjoining
floorboard by a pushing-together motion essentially parallel
with the surface plane of the laid floorboard for snapping
together the parts of the locking system during downward
bending of the lower lip of the tongue groove.
CA 02433487 2009-05-14
22055-270
20d
A plurality of aspects of the invention are also
applicable to the known systems without these aspects being
combined with the preferred locking systems described here.
The invention also describes the basic principles
that should be satisfied for a tongue and groove joint which
is to be snapped in with a minimum bending of joint
CA 02433487 2003-07-01
i ~
FCT/SE02100042
10-01-2003
21
components and wi.th the surface planes of the floorboards
- on essentially th.e same level.
The invention also describes how material properties
can be used to achieve high strength and 1ow cost in com-
bi.nation with snapping.
Different aspects of the i.nvention will now be
described in more detail with reference to the accom-
panying drawings which show different embodiments of the
invention. The parts of the inventive board that are
equivalent to those of the prior-art board in Figs 1-2
have throughout been given th.e same reference numerals.
Brief Description of the Drawings
Figs 1a-c show in three steps a downward angling
method for mechanical joining of lon.g sides
of floorboards accordzng to WO 9426999.
Fi.gs 2a-c show in three steps a snappin.g-in method for
mechanical joining of short sides of floor-
boards according to WO 9426999.
Figs 3a-b show a floorboard according to WO 9426999
seen from above and from below respectively.
Figs 4a-b show two different embodiments of floorboards
according to WO 9966151.
Figs 5a-b show floorboards according to GB 1430423.
Figs 6a-b show mechanical locking systems for the long
side or the short side of floorboards accord-
i.ng to WO 9627721.
Figs 7a-b show a mechanical locking system according to
JP 3169967.
Figs 8a-b show boards according to DE-A-1212275.
Figs 9a-b show a snap joi.nt according to WO 9747834.
Figs 10a-b show a snap join.t according to FR 2675174.
Figs lia-b schematically illustrate two para11e1 joint
edge portions of a first preferred embodiment
of a floorboard according to the present
invention.
Figs 12a-c show snapping-in of a variant of the inven-
tion.
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CA 02433487 2003-07-01
1-7 PCTh"E02100042
10-01-~003
~---
- 22
Figs 13a-c show a downward and upward angling method
using the in.vention.
Fig. 14 shows snapping-in of a production-adapted
variant of the.invention.
Fig. 15 shows this variant of the invention to illu-
strate taking-up by upward angli.ng while
using bending and compression in the joint
material.
Figs 16a-c show examples of a floorboard accordin.g to
the inven.tion.
Figs 17a-c show how the joint system should be designed
to facilitate snapping-in.
Fig. 18 shows snapping-in in an angled position.
Fig. 19 shows locking of short side with snapping-in.
Figs 20a-b show snapping-in of the outer and inner cor-
ner portion of the short side.
Fig 21 shows a joint system according to the inven-
tion with a flexible ton.guee
Figs 22a-e show in detail snapping-in of the outer cor-
ner porti.on of the short side by using an
embodiment of the invention.
Figs 23 a-e illustrate in detail snapping-in of the inner
corner portion of the short side by using an
embodiment of the invention.
Detailed. Description of Preferred Embodiments
A first preferred embodiment of a floorboard 1, 11,
which is provided with a mechanical locking system
according to the inventi.on, will now be described with
reference to Figs 11a and llbe To facilitate the under-
standing, the joint system is shown schematically. Tt
should be ernphasised that a better function can be
achieved with other preferred embodiments that will be
described below.
Figs 11a, llb show schematically a sect.ion through
a joint between a long side edge portion 4a of a board
1 and an opposite long side edge portion 4b of another
board 1 .
.
.
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CA 02433487 2003-07-01
rcTisE02i00042
10-01-2003
- ~
23
The upper sides of the boards are essentially posi-
- tioned in a common surface p.~~.ane HP and th.e upper parts
of the joint edge portions 4a, 4b engage each other in
a vertical joint plane VP. The mechan.ical locking system
results in locking of the boards relative to each other
in both the vertical direction D1 and the horizontal
direction D2 which extends perpen.dicular to the joint
plane VP. During the laying of a floor with juxtaposed
rows of boards, one board (1'), however, can be di.splaced
along the other board (1) in a direction D3 (see Fig. 19)
along the joint plane VP. Such a displacement can be
used, for instance, to provide locking-together of floor-
boards that are positioned in the same row.
To provide joining of the two joint edge portions
perpendicular to the vertical plane VP and parallel with
the horizontal plane HP, the edges of the tloorboard have
in a manner known per se a tongue groove 36 in one edge
portion 4a of the floorboard inside the joint plane VP,
and a tonggue 38 formed in the other joint edge portion 4b
and projecting beyond the joint plane VP.
In this embodiment the board 1 has a core or core 30
of wood which supports a surface layer of wood 32 on its
front side and a balancing layer 34 on its rear side. The
board 1 is rectangular and has a second mechanical lock-
ing system also on the two parallel short sides. In sorne
embodiments, this second locki.ng system can have the same
design as the locking system of the long sides, but the
locking system on the short sides can also be of a diffe-
rent design accordi.ng to the invention or be a previously
known mechanical locking system.
As an illustrati.ve, non-limiting example, the floor-
board can be of parquet type with a thickn.ess of 15 mm,
a length of 2.4 m and a width of 0.2 m. The invention,
however, can also be used for parquet squares or boards
of a different size.
The core 30 can be of larnella type and consist of
narrow wooden blocks of an inex.pensive kind of wood. The
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CA 02433487 2003-07-01 PCT~SE02 00042
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" 24
surf ace la.yer 32 may h.ave a thickness of 3-4 mm and con-
- sist of a decorative kind of hardwood and be varnished.
The balancing layer 34 of the rear side may consist of a
2 mm veneer layer. In some cases, i.t may be advantageous
to u.se different types of wood materials in different
parts of the floorboard for optimal properties wi.thin th.e
indi.vidual parts of the floorboard.
As mentioned above, the mechanical locking system
accordi.ng to the invention comprises a tongue groove 36
in one joint edge portion 4a of the floorboard, and a
tongue 38 on the opposite joint edge portion 4b of the
floorboard.
The tongue groove 36 is defined by u.pper and lower
lips 39, 40 and has the form of an undercut groove with
an opening between the two lips 39, 40.
The different parts of the tongue groove 36 are best
seen in Fig. 11b. The tongue groove is formed in the core
or core 30 and ex.tends from the edge of the floorboard..
Above the tongue groove, there is an upper edge portion
or joint edge surface 41 which extends up to the surface
plane HP. Inside the opening of the tongue groove, there
is an upper engaging or supporting surface 43 whzch in
this case is parallel with the surface plane HP. This
engaging or supporting surface passes into an inclined
locking surfa.ce 43 which has a locking angle A to the
horizontal plane HP. Inside the locking surfacef there is
surface portion 46 which forms the upper boundary surface
of the undercut portion 35 of the tongue groove. The
tongue groove further has a bottom end 48 which extends
down to the lower li.p 40. On the upper side of this lip
there i.s an engaging or supporting surface 50. The outer
end of the lower 1ip has a joint edge surface 52 which is
posi.tioned at a distance from the join.t plane VP.
The shape of the tongue is also best seen in
Fig. 11b. The tongue is made of the material of the core
or core 30 and exten.ds beyond the joint plane VP when
this joi.nt edge portion 4b is mechanically joined with
::[)(l: - [j . 1) 1 .~,(1 7 .:'i y }1c.~ - f _ i ) .:. r1 i-
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CA 02433487 2003-07-01
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PCT/SE02100042
10-O1-2003
the joint edge portion 4a of an adjoining floorboard. The
joint edge porti.on 4b also has an upper edge portion or
upper joint edge surface 61 which extends along the joint
plane VP down to the root of the tongue 38. The upper
5 side of the root of the tongue has an upper engaging or
supporting surface 64 which in this case extends to an
inclined locking surface 65 of an upwardly directed por-
tion 8 close to the tip of the tongue. The locking sur-
face 65 passes into a guidi.ng surface portion 66 which
10 ends in an upper surface 67 of the upwardly directed
portion 8 of the tongue. After the surface 67 follows
a bevel which may serve as a guiding surface 68. Th.i.s
extends to the tip 69 of the tongue. At the lower end
of the tip 69 there is a further guiding surface 70
15 which extends obli.quely downwards to the lower edge of
the tongue and an engaging or supporting surface 71. The
supporti.ng surface 71 is intended to coact with the sup-
porting surface 50 of the lower lip when two such floor-
boards are mechanically joined, so that their upper sides
20 are posi.ti.oned in the same surface plane HP and meet at
a joint plane VP directed perpendicular thereto, so that
the upper jo.int edge surface 41, 61 of the boards engage
each other. The tongue has a lower joi.nt edge surface 72
which extends to the underside.
25 In this embodiment there are separate engaging or
supporting surface 43, 64 in the tongue groove and on the
tongue, respectively, which in'the locked state engage
each other and coact with the lower supporting surfaces
50, 71 on the lower lip and on the tongue, respectively,
to provide the locking in the direction D1 perpendicu.lar
to the surface plane HP. In other embodiments, which will
be described below, use is made of the lockin.g surfaces
45, 65 both as locking surfaces for locking together in
the direction D2 parallel with the surface plane HP and
as supporting surfaces for counteracting movements in the
direction Dl perpendi.cular to the surface plane. In the
embodiment according to Figs 11a, 2b, the locking sur-
~t}t}3- r_ie:lktx~'[: a,,.~ ~ , ,- ,, .
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CA 02433487 2003-07-01
PCTOSE02I00042
~ 1 - 1-2 3
" 26
faces 45, 65 and.the engaging surfaces 43, 64 coact as
upper supporting surfaces in the system.
As is apparent from th.e drawing, the tongue 38
extends beyond the joint plane VP and has an upwardly
directed portion 8 at its free outer end or tip 69. The
tongue has also a locking surface 65 which is formed to
coact with the inner locki.ng surface 45 in the tongue
groove 36 of an adjoining floorboard when two such floor-
boards are mechani.cally joined, so that their front sides
are positioned in the same surface plane HP and meet at a
joint plane VP directed perpendicular theretoa
As is eva.dent from Fig. 11b, the tongue 38 has a
surface portion 52 between the locking surface 51 and
the joi.nt plane VP. When two floorboards are join.ed, the
surface portion 52 engages the surface portion 45 of the
upper lip 8. To faci.litate insertion of the tongue into
the undercut groove by inward angling or snapping-in the
tongue can, as sh.own in. Figs 11a, 11b, have a bevel 66
between the locki.ng surface 65 and the surface portion
57. Moreover, a bevel 68 can be positioned between the
surface portion 57 and the tip 69 of the tongue. The
bevel 66 may serve as a guiding part by having a 1.ower
angle of inclination to the surface plane than the angle
of inclination A of the locking surfaces 43, 51.
The support-ing surface 71 of the tongue is in this
embodiment essent.iallyy parallel with the surface plane
HP. The tongue has a bevel 70 between thi.s supporting
surface and the tip 69 of the tongue.
According to the invention, the lower lip 40 has a
supporting surface 50 for coaction with the corresponding
supporting surface 71 on the tongue 36. In thi.s embodi-
ment, this supporting surface is posits.on.ed at a distance
from the inner part 47 of the un.dercut groove. G+Ihen two
floorboards are joined with each other, there is engage-
ment both between the supporting surfaces 50, 71 and
between the engaging or supporting surface 43 of the
upper lip 39 and the corresponding engaging or supporting
t~~ryy
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C,A 02433487 2003-07-01
PCUSE02100042
~-~ 10-01-2003
' 27
surface 64 of the tongue. In this way, locking of the
boards in the direction DI perpendicular to the surface
plane HP is obtained.
Preferably, at least the major part of the inner
part 47 of the undercut groove, seen parallel with the
surface plane HP, is located further away from the joint
plane VP than is the outer end or tip 69 of the tongue
36. By this design, manufacture is simplified to a con-
siderable extent, and di.splacement of one floorboard
30 relative to another along the joint plane is facili.tated.
Another important feature of a mechanical locking
system accord.ing to the invention is that all parts of
the portion.s of the lower lip 40 which are connected with
the core 30, seen from the point C, where the surface
plane HP and the joint plane VP intersect, are located
outside a plane LP2. This plane is located further away
from sai.d point C than a locking plane LP1. which is
parallel with the plane LP2 and which is tangent to the
coacting locking surfaces 45, 65 of the undercut groove
36 and the tongue 38, where these locking surfaces are
most inclined relative to the surface plane HP. Owing to
this design, the undercut groove can, as will be describ-
ed in more detail below, be made by using large disk-
shaped rotating cutti.ng tools for machining of the edge
portions of the floorboards.
A further important feature is that the lower lip
40 is resilient and that it is shorter than the upper lip
39. This enables production of the undercut using large
rotating cutting tools which can be set at a relatively
high angle to the horizonta.l plane, so that the locking
surface 65 can be made with a high locking angle A. The
high locking angle significantly reduces the downward
component that arises in connecti.on with tensile load.
This means that the joint system will have high strength
although the lower lip is resilient and thus has a lima.t-
ed capability of counteracting a downward component. This
results in optimisation for obtaining a high locking
:
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,=;~ z p t) ~? r=
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28
force in combination with lower resistance to snapping-
in. High resistance to snapping-i.n makes snapping-i.n
diffa.cu.lt and increases the risk of damage to th.e joint
edge portions of the floorboards. The inventor has found
that most materials used in floorboard.s can be made suf-
ficiently resilient by being formed with lips of a suit-
able thickness a.nd length which can work in the preferred
joint system and provi.de sufficien.t locking force.
Figs 12a-c show snapping-in of two floorboards by
bending of the lor,ver lip 40. As is evident from Fig. 12b,
snapping-.in takes place with a minimum bending of the
lower lip and wi.th the surface planes of the floorboards
on essentially the same level. Th.is reduces the risk of
cracking.
Figs 13a-c show that the locking system according to
Figs 12a-c can also be used for upward angling and down-
ward angling in connection with taki.ng-up and laying. The
upper and lower lips 39, 40 and the tongue 38 are formed
to enable disconn.ection of two mechanically joined
floorboards by one floorboard being pi.voted upwards rela-
tive to the other about a pivoting centre close to the
intersection C between the surface plane HP and the joint
plane VP so that the tongue of this floorboard is pivoted
out of the undercut groove of the other floorboard.
The snap joint according to the invention can be
used on both long side and short side of the floorboards.
Fig. 14 and Fig. 15 show, however, a variant of the
invention which is above all suited for snappi.ng along
the short side of a floorboard which is made of a rela-
tively hard material, such as a hard kind of wood or a
hard fibreboard.
In this embodiment, the tongue groove is essential-
ly deeper than is required to receive the tongue. As a
result, a higher bendability of the lower lip 40 is
obtained. Moreover, the locking system has a long tongue
with a thick locki.ng element 8. The locking surfaces 45,
.
c-
.) Y:.-
,~'{ . Tt,r.=~u: >>xz<<'pi~t}1 . ~
i~C;Qf tic ta.L .cx:~.itu<skLt.s`?201 ~ildcd % Op.I.dc..
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10-01-2003
29
65 are also heavily inclined. The dashed line indicates
- the snapping motion.
The design according to Figs 14 and 15 allow discon-
nection by upward angling of one board and a slight down-
ward bendi.ng of the lower lip 40 of the other board.
However, i.n other more preferred embodiments of the
invention, no downward ben.ding of the lower lip is
necessary when disconnecting the floorboards.
In the locked position, it is possible to displace
the floorboards in the longitudinal directi.on of the
joi.nt. As a result, disconnection of, for examp7.e, the
short sides can take place b_y pulling out in the longi-
tudinal direction of the joint after disconnection of the
long sides by, for instance, upward angling.
To facilitate manufacture, inward angling, upward
angling, snapping-in and displaceability in the locked
position and to mi.nimise the risk of creaking, a11 sur-
faces that are not operati.ve to form a joint with tight
upper joint edges and the vertical and horizontal joint
should be formed so as not to be in contact with each
other in the locked position and preferably also during
locking and unlocking. Thi.s allows manufacture without
requiri.ng high tolerances in these joint portions and
reduces the friction i.n lateral displacement along the
'j oint edge. Ex.amples of surfaces or parts of the j oint
system that should not be in contact with each other in
the locked position are 46-67, 48-69, 50-70 and 52-72.
The join.t svstem accordi.ng to the preferred embodi-
ment may cons.ist of several combinations of materials.
The upper lip 39 can be made of a rigid and hard upper
surface layer 32 and a softer lower part which is part
of the core 30. The lower lip 40 can consist of the same
softer upper part 30 and also a lower soft part 34 which
can be another kind of wood. The directions of the fibres
i.n the three kinds of wood may vary. This can be used to
provide a joint system which utilises these material pro-
perties. The locking element i.s therefore according to
,,.
i =.
~i)i):;..i) ...ng lp:~ r: ,`>~= r_ ti1 urk. :., D
,_.
- c,-= .
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PCTI5E02I00042
~
10-01-2003
' 30
the invention positioned closer to the upper hard and
- rig-i d part, which thus is -flexible and compressible to a
limited extent only, while th.e snap function is formed in
the softer lower and flexible part. It shou.ld be pointed
that the joint system can also be made in a homogeneous
floorboard.
Figs 16a-c illustrate an example of a floorboard
according to the inventione This embodiment shows speci-
fically that the joint system on long side and short side
is differently designed. On the short side, the locki.ng
system is optimised for snapping by means of a high lock-
ing angle, deeD tongue groove and upper lip shorter than
lower lip while at the same time the lockin.g surfaces
have a low height to reduce the requirement for downward
bendin.g. On the long side, the joint system has been
adjusted for joinin.g/taking-up by angular motions.
Moreover, the joint system may consist of different
materials and combinations of rnaterials 30a, 30b and 30c.
It is also possible to select di.fferent materials on long
and short sides. For example, the groove part 36 of the
short sides may consist of a harder and more flexible
wood materi.al than, for ira.stance, the tongue part 38
which can be hard and rigid and have other properties
than the core of the long side. On the short side with
the tongue groove 36 it is possi.ble, for instance, to
choose a kind of wood 30b which is m.ore flex.ible than
the kind of wood 30c on the other short side where the
tongue is formed. This is particularly convenient in
parquet floors with a lamellar core where the upper and
lower side consist of different kinds of wood and the
core consists of glued blocks. This construction gives
great possibili.ties of varying the composition of mate-
rials to optimise functi.on, strength and production cost.
zt is also possible to vary th.e material along the
length of a side. Thus, for instance the blocks that are
i
positioned between the two short sides can be of diffe-
' rent kinds of wood or materials so that some can be
. .
I
.:., . ,..,, . ..96,
,: . _ .
_ ~ .., .
_f)q_s.pt...iic=, -~f):~r . ~`,~:jarP;:'wai~~'i'tn
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.: ,
_,..n~, ~..!, .. ~ '~~= r,~,= ir.;r.' ~ =
n.. = t C ~
;.~, ~= .,= =z' docurtCt_.a'.4L3~ c.i_,.c... ._..a. ~..
1d
__. . I
CA 02433487 2003-07-01
PCTI5E02100042
POe
- 10-0x-2003
-' 3 l
selected with regard to their contributing suitable
_ properties which improve laying, strength etc. Different
properties can also be achieved with different orienta-
tion of fibres on long side and short side, and also
plastic materials can be used on the short sides and, for
instance, on di.fferent parts of the long side. If the
floorboard or parts of its core consa.st of e.g. plywood
with several layers, these layers can be selected so that
the upper lip, the tongue and the lower lip on both long
side and short side can all have parts wi.th different
composition of materials, orientation of fibres etc.
which may give different properties as regards strength,
bendability, machinability etc.
Figs 17a-c show the basic principl.e of how the lower
part of the tongue should be designed in relation to the
lower li.p 40 so as to facilitate a horizontal snapping--in
according to the invention in a join.t system with an
undercut or locking groove 8 in a rigid upper lip 39 and
with a flexible lower lip 40. In this embodiment, the
upper lip 39 is significantly more rigi.d, amon.g other
things ow3ng to the fact that it can be thicker or that
it may consist of harder and more rigid materials. The
lower li.p 40 can be thinn.er and softer and the essential
bendingg will therefore, in connection with snapping-in,
take place in the lower lip 40. Snapping-i.n can be signi-
ficantly facilitated among other things by the maximum
bending of the lower lip 40 being limited as far as pos-
sible. Fig. 17a shows that the bendin.g of the lower lip
40 will increase to a maximum bending level Bl which is
characterized in that the tongue 38 is inserted so far
into the tongue groove 36 that the rounded guiding parts
come into contact with each other. When the tongue 38 is
inserted still more, the lower lip 40 will be bent back
un.ti.l the snapping-in is terminated and th.e locking ele-
ment 8 is fully inserted in its final position in the
undercut 35. The lower and front part 49 of th.e tongue 38
should be designed so as not to bend down the lower li.p
NIP . ~11i ~{~,~ _
,i:=,i?iri;:i_ i r~G;;ua;c;nCe'<01':'._, T:x,dc:d 1'))= C?PL:.dOC
CA 02433487 2003-07-01
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'(~~' ~: ~':V=~~s~~.~~." t~,~:~Ã;~.~a~'v~-~t
10_01-2003
- 32
40 whi.ch instead should be forced downward by the iower
. supporting surface 50. This part 49 of the tongue should
have a shape which either touches or goes clear of the
maxi.mum bending level of the lower lip 40 when this lower
lip 40 is bent along the outer part of the lower engaging
surface 50 of the tongue 38. If the tongue 38 has a shape
which in this position overlaps the 1.ower lip 40, indi-
cated by the dashed line 49b, the bending B2 according to
Fig. 17b can be significantly greater. This may result i.n
high friction in connection with sn.apping-in and a risk
of the joint being damaged. Fig. 17c shows that the maxi-
mum bendin.g can be limited by the tongue groove 36 and
the tongue 38 being designed so that there is a space S4
between th.e lower and outer part 49 of the tongue and the
lower lip 40. The upper lip being made more rigid and, the
lower lip more flexible reduces th.e risk of edge ri.sing
on the upper side of the laid floor as the floor shrinks
and swells depend.ing on the relati.ve humidity of th.e
indoor air. The greater rigidi.ty of the upper lip in
combinat.ion with the arrangement of the locking surfaces
also makes it possible for the joint to take up great
pulling-apart forces transversely of the joint. Also the
bendi.ng away of the lower lip contributes to minimisi.ng
the risk of edge rising.
Hori2ontal snapping-in is normally used in connec-
tion wi.th snapping-in of the short side'after locking of
the long side. When snapping-in the long side, it is also
possible to snap the joint system accordin.g to the inven-
tion with one board in a slightly upwardly angled posi-
tion. This upwardly angled snap position is illustrated
i.n Fig. 18. Only a smalZ degree of bend.i.ng B3 of the
lower lip 40 is necessary for the gu.iding part 66 of the
locking element to come into contact with the guiding
part 44 of the locking groove so that the locking element
can then by downward an.gling be inserted into the under-
cut 35.
.:1)1)3 ...(}1 _Q9 itJ:2 i V.`.~;J:i?q1iR:.:~iTrC. ' ~~~17'~.'~~7 ..af. f~^~~
ynP:-}l.:i?i=~!lfl:~.i''.~IJ.~1.~~:~; ..
1-~ -PC.i.{:~'1CJ.u,_ (~,(iC:1:.C~L`:':~Lt.G'S'-,l\t?,_
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1 CA 02433487 2003-07-01
F 'trCi vs Pa5'an4 ONt; 0 PCT/SE02/00042
10-01-2003
33
Figs 19 and 20 also describe a problem which can
arise in connection with snapping-in of two short sides
of two boards 2a and 2b which are already joined on their
long sides with another first board 1. When the floor-
board 2a is to be joined with the floorboard 2b by snap
acti.on, the inner corner portions 91 and 92, closest to
the long side of the fi.rst board 1, are positioned in the
same plane. This is due to the fact that the two boards
2a and 2b on their respective long sides are joined to
the same floorboard 1. According to Fig. 20b, which shows
the section C3-C4, the tongue 38 cannot be inserted into
th.e tongue groove 39 to begin th.e downward bending of the
lower lip 40. Tn the outer corner portions 93, 94 on the
other long side, in the section C3-C4 shown in Fig. 20a,
the tongue 38 can be inserted into the tongue groove 36
to begin the down.ward bending of the lower lip 40 by the
board 2b being automatically pressed and angled upwards
corresponding to the height of the locking element 8.
The inventor has thus discovered that there may be
problems in connection with snapping-in of inner corner
portions in lateral displacement in the same plane when
the ton.gue is formed with an upwardly directed portion at
its tip and is to be in.serted into a tongue groove wi.th
an undercut. These problems may cause a high resistance
to snapping-in and a ri.sk of cracking in the joint
system. The problem can be solved=by a suitable join.t
design and choice of materials which enabZe material
deformation and bending in a plurality of joint portions.
When snapping-in such a specially designed joint
system, the following takes place. Tn-lateral displace-
ment, the outer guiding parts 42, 68 of the tongue and
the upper 1.ip coact and force the upwardly directed
porti.on or locking element 8 of the tongue under the
outer part of the upper lip 39. The tongue bends downward
and the upper lip bends upward. This is indicated by
arrows in Fig. 20b. The corner portion 92 in Fig. 19 is
pressed upward by the lower lip 40 on the long side of
.-;0 1):i- q =--09 l_fj : ' ..7 V ;:pe^.a.Zilkt '
~~~ ~ , z:m~ud'~ b ' C?4,
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CA 02433487 2003-07-01 `
4
~`9~' ~t=^csr~'3`''.~ ~'D~,~ '','.; ~~'~=/'- ai'~..,
PCTfSE02100042
< 10-01-2003
' 34
the board 2b being bera.t and the corner portion 91 being
pressed downward by the upper lip on the long side of the
board 2a being bent upward. The joint system should be
con.structed so that the sum of these four deformations is
so great that the locking element can slide along the
upper li.p and snap into the undercut 35. It is known that
it should be possible for the tongue groove 36 to widen
i.n connection with snapping-in. However, it is not known
that it may be an advantage if the tongue, wh.ich normally
should be ri.gid, should also be designed so as to be able
to bend in connection with snappin.g-in.
Such an embodiment is shown in. Fig. 21. A groove or
the like 63 is made at the upper and i.nner part of the
tongue inside the vertical plane VP. The entire extent PB
of the tongue from its inner part to its outer part can
be extended, and it can, for instance, be made greater
than half the floor thickness T.
Figs 22 and 23 show how the parts of the joint sys-
tem bend in connection with snapping-in at the inner
corner portion. 91, 92 (Fig. 19) and the outer corner por-
tion 93, 94 (Fig. 19) of two floorboards 2a and 2b. To
simplify manufacture, it is required that only the thin
lip and the tongue bend. In practice, of course all parts
that are subjected to pressure will be cornpressed and
bent to a varying degree depending on thickness, bendabi-
lity, composition of materials etc.
Fig. 22a shows the outer corner portion 93, 94 and
Fig. 23a shows the inner corner portion 91; 92. These two
Figures show the positi.on when th.e edges of the boards
come into contact with each other. The joint system is
designed so that even in this position the outermost tip
of the tongue 38 .is located inside the outer part of the
lower 1ip 40. When the boards are pushed towards each
other still more, the tongue 38 will in the inner corner
91, 92 press the board 2b upward according to Figs 22b,
23b. The tongue wi11 bend downward and the board 2b at
the outer corner portion 93, 94 will be angled upward.
_. ,
z~ .
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CA 02433487 2003-07-01
r~~,~s
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~~ ~c~~~~ : PCTlSE02/00042
~~~~~~~
TO 01-2003
- 35
Fig. 23c shows that the tongue 38 at the inner corn.er
91, 92 will be bent downward_ At the outer corner 93, 94
according to Fig. 22c, the tongue 38 is bent upward and
the lower lip 40 downward. A.ccording to Figs 22d,, 23d,
this bending continues as the boards are pushed towards
each other still more and now also the lower lip 40 is
bent at the inner corner 91, 92 according to Fig. 23d.
Figs 22d, 23e show the snapped-in position. Thus,
snapping-i.n can be facilitated significantly if the
tongue 38 is also flexible and if the outer part of the
tongue 38 is positioned inside the outer part of the
lower lip 40 when tongue and groove come into contact
with each other when the boards are positioned in the
same pla.ne in connection with snapping-in that takes
place after locking of the floorboard along its two other
sides.
Several variants can exist within the scope of the
i.nvention. The inventor has rnanufactured and evaluated
a large number of variants where the different parts of
the joint system have been manufactured with different
widths, lengths, thicknesses, angles and radii of a num-
ber of different board materials and of homogeneous plas-
tic and wooden panels. All joint systems have been tested
in a position turned upside-down and with snapping and
angling of groove and tongue boards relative to each
other and wi.th different combinations of the systems here
described and also prior-art systems on long side and
short side. Locking syatems have been manufactured where
locking surfaces are also upper engaging surfaces, where
the tongue and groove have had a plurality of locking
elements and locking grooves, and where also the lower
lip and the lower part of the tongue have been formed
with horizontal locka.ng means in the form of locking ele-
ment and locking groove.
p C::`:=`.',J;?~S.i'1~~:t 1q~~ 'i
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