U.S. patent application number 09/981090 was filed with the patent office on 2003-01-16 for joining system and method for floor boards and boards therefor.
Invention is credited to Palmberg, Ulf.
Application Number | 20030009971 09/981090 |
Document ID | / |
Family ID | 8184880 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030009971 |
Kind Code |
A1 |
Palmberg, Ulf |
January 16, 2003 |
Joining system and method for floor boards and boards therefor
Abstract
The invention relates to a joining system and method for
floorboards, e.g. for parquetry. The joining system comprises floor
boards intended to be joined with each other, wherein a first board
(A) has a protrusion fitting into a recess in a second board (B).
The protrusion on the first board comprises hooks (1) with
intermediate slots (2) or chamfers. The recess (11) in the second
board (B) is delimited on the top side by a solid edge (3), and on
the bottom side by an edge having heads (4) dimensioned to be
inserted through the slots (2) of the first board (A). The
invention will replace the traditional groove and tenon technique.
By providing slots or chamfers in the protrusion corresponding to
the tenon, and corresponding cuts in the lower limiting edge of the
groove, the boards can be joined in a substantially vertical or
transversal movement and then be locked by a horizontal movement in
the longitudinal direction of the boards. At the same time, the
protrusion is shaped like hooks engaging the groove. Hereby, the
joining will be very simple to perform, whilst at the same time
providing a strong joint.
Inventors: |
Palmberg, Ulf; (Ronneby,
SE) |
Correspondence
Address: |
Richard J. Streit
Ladas & Parry
Suite 1200
224 South Michigan Avenue
Chicago
IL
60604
US
|
Family ID: |
8184880 |
Appl. No.: |
09/981090 |
Filed: |
October 16, 2001 |
Current U.S.
Class: |
52/578 ;
52/591.2; 52/592.1 |
Current CPC
Class: |
E04F 2201/0123 20130101;
E04F 2201/022 20130101; E04F 15/04 20130101; E04F 15/02 20130101;
E04F 2201/07 20130101 |
Class at
Publication: |
52/578 ;
52/591.2; 52/592.1 |
International
Class: |
E04C 003/00; E04B
002/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 16, 2001 |
EP |
01850125.4 |
Claims
1. A joining system for floor boards, comprising boards intended to
be joined with each other, wherein a first board has a protrusion
fitting into a recess in a second board, wherein said protrusion on
the first board comprises hooks with intermediate slots; and said
recess in the second board being delimited on the top side by a
solid edge; and on the bottom side by an edge having heads; said
hooks on the first board being dimensioned to be able to pass
between the heads on the second board.
2. A joining system according to claim 1, wherein the hooks exhibit
profiled top sides; and the solid edge having a correspondingly
profiled underside.
3. A joining system according to claim 2, wherein the top side of
the hooks is configured with a straight angled top; and the solid
edge is configured with a correspondingly shaped downwardly facing
inner side.
4. A joining system according to claim 2, wherein the top side of
the hooks is configured with a flat top; and the solid edge is
configured with a correspondingly shaped downwardly facing inner
side.
5. A joining system according to claim 2, wherein the lower side of
the hooks is configured with a projection; and the solid edge is
configured with a correspondingly shaped upwardly facing inner
side.
6. A joining system according to claim 1, wherein the bottom edge
of said recess exhibits shoulders between the heads.
7. A joining system according to claim 6, wherein said shoulders
have a rounded upper edge.
8. A joining system according to claim 1, wherein the hooks, the
slots and the heads have substantially the same size in the
longitudinal direction of the boards.
9. The joining system according to claim 8, wherein the heads are
slightly narrower than the slots.
10. A joining system according to claim 1, wherein the short sides
of the boards are provided with grooves and tenons fitting into
each other.
11. A board for a joining system, having a protrusion on a first
long side of the board and a recess on a second long side of the
board, said protrusion fitting into said recess, wherein said
protrusion on said first long side comprises hooks with
intermediate slots; and said recess in said second long side being
delimited on the top side by a solid edge, and on the bottom side
by an edge having heads, said hooks being dimensioned to be able to
be pass between heads on another identical board, thus allowing
identical such boards to be joined with each other.
12. A board according to claim 11, wherein the hooks exhibit
profiled top sides and by the solid edge having a correspondingly
profiled underside.
13. A board according to claim 12, wherein the top side of the
hooks is configured with a straight angled top; and the solid edge
is configured with a correspondingly shaped downwardly facing inner
side.
14. A board according to claim 12, wherein the top side of the
hooks is configured with a flat top; and the solid edge is
configured with a correspondingly shaped downwardly facing inner
side.
15. A board according to claim 12, wherein the lower side of the
hooks is configured with a projection; and the solid edge is
configured with a correspondingly shaped upwardly facing inner
side.
16. A board according to claim 11, wherein the bottom edge of said
recess exhibits shoulders between the heads.
17. A board according to claim 16, wherein said shoulders have a
rounded upper edge.
18. A board according to claim 11, wherein the hooks, the slots and
the heads have substantially the same size in the longitudinal
direction of the boards.
19. A board according to claim 18, wherein the heads are slightly
narrower than the slots.
20. A board according to claim 11, wherein the short sides of the
boards are provided with grooves and tenons, allowing identical
such boards to be joined with each other.
21. A joining system for floor boards, comprising boards intended
to be joined with each other, wherein a first board has a
protrusion fitting into a recess in a second board, wherein said
protrusion on the first board having chamfers with intermediate
hook-shaped portions and having a solid top edge; and said recess
in the second board being delimited on the top side by a solid
edge; and on the bottom side by an edge having heads; said
hook-shaped portions on the first board being dimensioned to be
able to pass between the heads on the second board.
22. A joining system according to claim 21, wherein the hook-shaped
portions exhibit profiled top sides; and the solid edge of the
recess having a correspondingly profiled underside.
23. A joining system according to claim 22, wherein the top side of
the hooks is configured with a flat top; and the solid edge of the
recess is configured with a correspondingly shaped downwardly
facing inner side.
24. A joining system according to claim 22, wherein the lower side
of the hooks is configured with a projection; and the solid edge of
the recess is configured with a correspondingly shaped upwardly
facing inner side.
25. A joining system according to claim 21, wherein the bottom edge
of said recess exhibits shoulders between the heads.
26. A joining system according to claim 25, wherein said shoulders
have a rounded upper edge.
27. A joining system according to claim 21, wherein the hook-shaped
portions, the camfers and the heads have substantially the same
size in the longitudinal direction of the boards.
28. The joining system according to claim 27, wherein the heads are
slightly narrower than the chamfers.
29. A joining system according to claim 21, wherein the short sides
of the boards are provided with grooves and tenons fitting into
each other.
30. A board for a joining system, having a protrusion on a first
long side of the board and a recess on a second long side of the
board, said protrusion fitting into said recess, wherein said
protrusion on said first long side comprises chamfers with
intermediate hook-shaped portions; and said recess in said second
long side being delimited on the top side by a solid edge, and on
the bottom side by an edge having heads, said hook-shaped portions
being dimensioned to be able to be pass between heads on another
identical board, thus allowing identical such boards to be joined
with each other.
31. A board according to claim 30, wherein the protrusion exhibits
a profiled top side and by the solid edge of the recess having a
correspondingly profiled underside.
32. A board according to claim 31, wherein the top side of the
protrusion is configured with a flat top; and the solid edge is
configured with a correspondingly shaped downwardly facing inner
side.
33. A board according to claim 30, wherein the lower side of the
hook-shaped portions is configured with a projection; and the solid
edge of the recess is configured with a correspondingly shaped
upwardly facing inner side.
34. A board according to claim 30, wherein the bottom edge of said
recess exhibits shoulders between the heads.
35. A board according to claim 34, wherein said shoulders have a
rounded upper edge.
36. A board according to claim 30, wherein the hook-shaped
portions, the chamfers and the heads have substantially the same
size in the longitudinal direction of the board.
37. A board according to claim 36, wherein the heads are slightly
narrower than the chamfers.
38. A board according to claim 30, wherein the short sides of the
boards are provided with grooves and tenons, allowing identical
such boards to be joined with each other.
39. A method of joining floor boards, utilizing boards intended to
be joined with each other, wherein a first board has a protrusion
fitting into a recess in a second board, said protrusion on the
first board comprising hooks with intermediate slots; and said
recess in the second board being delimited on the top side by a
solid edge; and on the bottom side by an edge having heads and
shoulders between the heads; said hooks on the first board being
dimensioned to be able to pass between the heads on the second
board, comprising the steps of: when the first board is laid in
place and to be joined with the second board, fitting the second
board from above in such a way that the heads will pass through the
slots of the first board; angling the second board somewhat, and
holding it at an appropriate distance from the first board, so that
the shoulders will be allowed to pass the hooks; moving the second
board downwards until, the solid edge of the second board abuts the
top side of the hooks; pushing the shoulders under the hooks
through pivoting and pushing the two boards together; displacing
the second board longitudinally.
40. A method of joining floor boards according to claim 39, wherein
the joint is reinforced by glue, applied to the top side of the
hooks before mounting the second board.
41. A method of joining floor boards, utilizing boards intended to
be joined with each other, wherein a first board has a protrusion
fitting into a recess in a second board, said protrusion on the
first board comprising hooks with intermediate slots; and said
recess in the second board being delimited on the top side by a
solid edge; and on the bottom side by an edge having heads and
shoulders between the heads; said hooks on the first board being
dimensioned to be able to pass between the heads on the second
board, comprising the steps of: when the first board is laid in
place and to be joined with the second board, laying the second
board on the existing ground next to the first board in such a way
that the heads are located straight in front of the slots of the
first board and the hooks straight in front of the shoulders;
pushing the boards together so that the hooks pass under the solid
edge, past the shoulders and into the recess; displacing the second
board longitudinally.
42. A method of joining floor boards according to claim 41, wherein
the joint is reinforced by glue, applied to the top side of the
hooks before mounting the second board.
43. A method of joining floor boards, utilizing boards intended to
be joined with each other, wherein a first board has a protrusion
fitting into a recess in a second board, said protrusion on the
first board comprising chamfers with intermediate hook-shaped
portions; and said recess in the second board being delimited on
the top side by a solid edge; and on the bottom side by an edge
having heads and shoulders between the heads; said hook-shaped
portions on the first board being dimensioned to be able to pass
between the heads on the second board, comprising the steps of:
when the first board is laid in place and to be joined with the
second board, laying the second board on the existing ground next
to the first board in such a way that the heads are located
straight in front of the chamfers of the first board and the
hook-shaped portions straight in front of the shoulders; pushing
the boards together so that the hook-shaped portions pass under the
solid edge, past the shoulders and into the recess; displacing the
second board longitudinally.
44. A method of joining floor boards according to claim 43, wherein
the joint is reinforced by glue, applied to the top side of the
protrusion before mounting the second board.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a joining system and method
for floorboards, panels and sheaves, but foremost for parquetry.
The invention will replace the traditional groove and tenon
technique. By providing slots or chamfers in the protrusion
corresponding to the tenon, and corresponding cuts in the lower
limiting edge of the groove, the boards can be joined in a
substantially vertical or transversal movement and then be locked
by a horizontal movement in the longitudinal direction of the
boards. At the same time, the protrusion is hook-shaped so that the
protrusion engages the groove. Through this, the joining will be
very simple to perform, whilst at the same time providing a strong
joint.
STATE OF THE ART
[0002] The traditional groove and tenon technique for floorboards
has been known in the art for a long time. Furthermore, there are a
number of alternative technical solutions available with various
shapes of protrusions and recesses. Through giving the protrusions
various hook-like shapes, a firmer locking has been achieved than
with the groove and tenon. During assembly, the boards are angled
in relation to each other, joined and pivoted to achieve a planar
floor surface and a simultaneous locking. Examples of this
technique are e.g. shown in WO 94/26999, U.S. Pat. No. 5,797,237
and U.S. Pat. No. 6,006,486. It is also known to complete the
locking with separate auxiliary locking elements. This is
illustrated e.g. in SE B 512 290.
[0003] However, it is not always easy to join the boards, as the
entire length of a protrusion on a board has to be fitted into the
recess of an existing, already laid-down board, before the new
board can be pivoted and locked into its final position. This is
especially difficult if the board is warped and not entirely
straight, and too long for one person to control both ends
simultaneously.
[0004] The present inventor has realised that the joining will be
simpler if the necessary angle between the boards is reduced and
the boards can be joined with an almost vertical movement. In
another embodiment the boards can be joined with an almost
transversal movement. This is achieved by providing milled slots or
chamfers in the protrusions and in the lower edge of the recesses,
allowing the board to be joined to be inserted into the already
laid-down board more or less from above or from the side. The new
board can then be displaced longitudinally to obtain the final
locking thereof.
[0005] The invention allows for simple floor-laying that can easily
be performed by one person. At the same time, the board
manufacturing process is not made notably more complicated.
SUMMARY OF THE INVENTION
[0006] The invention thus relates to a Joining system for
floorboards, comprising boards intended to be joined together. The
first board has a protrusion fitting into a recess in the second
board.
[0007] According to the invention, the protrusion on the first
board exhibits hooks or hook-shaped portions with intermediate
slots or chamfers, and the recess of the second board is delimited
in the upwards direction by a solid edge, and in the downwards
direction by an edge with heads, sized so as to enable insertion
through the slots in the first board.
[0008] Preferably, the lower edge of the recess has shoulders
between the heads.
[0009] The invention also relates to a corresponding board for such
a joining system.
[0010] The invention also relates to corresponding joining
methods.
[0011] The invention is defined in the appended claims 1, 11, 21,
30, 39, 41 and 43, whereas preferred embodiments are described in
the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will be described in further detail below,
with reference to the enclosed drawings, of which:
[0013] FIG. 1 is a partial cross section view of two boards, taken
from the short side thereof, not joined together, according to one
embodiment of the present invention.
[0014] FIG. 2 is a view similar to FIG. 1, with the boards
joined.
[0015] FIG. 3 is a perspective view, illustrating the recess on one
long side of a board of the first embodiment.
[0016] FIG. 4 is a perspective view from the other side, showing
the hooks on the other long side of a board of the first
embodiment.
[0017] FIG. 5 is a view corresponding to FIG. 3, with joined boards
before being diplaced to the final position.
[0018] FIG. 6 is a view corresponding to FIG. 4, with joined boards
in the final position.
[0019] FIG. 7 is a partial cross section view of two boards similar
to FIG. 1 of a second embodiment of the present invention.
[0020] FIG. 8 is a view similar to FIG. 7, with the boards
joined.
[0021] FIG. 9 is a perspective view, illustrating the recess on one
long side of a board of the second embodiment.
[0022] FIG. 10 is a perspective view from the other side, showing
the hooks on the other long side of a board of the second
embodiment.
[0023] FIG. 11 is a partial cross section view of two boards
similar to FIG. 1 of a third embodiment of the present
invention.
[0024] FIG. 12 is a view similar to FIG. 11, with the boards
joined.
[0025] FIG. 13 is a perspective view illustrating the recess on one
long side of a board of the third embodiment.
[0026] FIG. 14 is a perspective view from the other side, showing
the hooks on the other long side of a board of the third
embodiment.
[0027] FIG. 15 is a partial cross section view of two boards
similar to FIG. 1 of a fourth embodiment of the present
invention.
[0028] FIG. 16 is a view similar to FIG. 15, with the boards
joined.
[0029] FIG. 17 is a perspective view illustrating the recess on one
long side of a board of the fourth embodiment.
[0030] FIG. 18 is a perspective view from the other side, showing
the chamfers on the other long side of a board of the fourth
embodiment.
[0031] FIG. 19 is a partial cross section view of two boards
similar to FIG. 1 of a fifth embodiment of the present
invention.
[0032] FIG. 20 is a view similar to FIG. 18, with the boards
joined.
[0033] FIG. 21 is a perspective view illustrating the recess on one
long side of a board of the fifth embodiment.
[0034] FIG. 22 is a perspective view from the other side, showing
the chamfers on the other long side of a board of the fifth
embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0035] The invention will be illustrated by means of embodiments
where the floorboards are made of wood. It should be understood
that other materials, such as laminates, plastic, etc. could be
used just as well.
[0036] The term hook is generally intended to mean a projection
with a profiled shape the function of which is to engage a cavity.
The term head is generally intended to mean a projection jutting
out from a surface. The terms slot and cut are generally intended
to mean a space between two hooks and two heads, respectively. The
term solid is generally intended to mean a straight surface not
broken by a cut. The term non-solid is generally intended to mean a
surface broken by a cut or slot. The terms horizontal and vertical
are used for describing directions in relation to a board that is
lying on a horizontal surface as in a typical floor. However, as a
matter of course, the invention is equally applicable to boards for
wall and ceiling panels in any direction.
[0037] In FIGS. 1 and 2, two boards A and B are shown in a cross
sectional view from their short sides. The boards have an upper
wear layer 8 of hardwood and a carrier layer of simpler wood, as is
conventional. It should be understood that the boards A and B are
identical, but FIGS. 1 and 2 show only the joint between a right
hand long side of board A and a left hand long side of board B.
[0038] See also FIGS. 3, 4, 5 and 6, showing perspective views of
the boards. Instead of a traditional tenon, board A exhibits hooks
1 with intermediate milled slots or cuts 2. Board B has a recess
11, corresponding to a traditional groove. The recess is delimited
on the top side by a solid edge 3, and on the bottom side by a
non-solid edge comprising heads 4 with intermediate milled cuts.
Preferably, these cuts do not extend to the full depth of the
recess 11 but there is a shoulder 7 remaining. The function of the
shoulder 7 will be described below.
[0039] The joining is performed as follows:
[0040] Board A is laid in place and is to be joined with the next
board B.
[0041] Board B is fitted from above in such a way that the heads 4
will pass through the slots 2 of board A. Through angling board B
somewhat, and holding it at an appropriate distance from board A,
the shoulders 7 will be allowed to pass the hooks.
[0042] Eventually, the solid edge 3 of board B will abut the top
side 5 of the hooks 1, and the shoulders 7 can be pushed under the
hooks 1 through pivoting and pushing the two boards together.
[0043] Subsequently, board B can be displaced longitudinally, into
its correct position in relation to the walls and the other
floorboards. The heads 4 will thereby also be displaced to a
location below the hooks 1, to form a strong joint. The joint may
be further reinforced by glue, applied e.g. to the top side 5 of
the hooks before mounting board B. The shoulders 7 may for example
be about 2 mm long. It is also conceivable to mill away the
shoulders 7 completely, down to the bottom of the recess. Board B
can then be laid down entirely vertically, but at the same time,
the joint will be weakened, as the entire head 4 generally will not
happen to be located below a hook 1.
[0044] The top side 5 of the hook 1 is preferably angled, as is the
matching underside 6 of the recess 11. A suitable angle is about
45.degree.. The hooks may also have other profiled shapes than the
configuration shown with straight edges and a flat exterior end
surface, e.g. convexely or concavely rounded shapes or other curved
and hook-shaped configurations of which some embodiments are
described below. The recess will have a more or less complementary
shape. The main point is that the configuration should result in
that the boards A and B cannot be pulled away from each other
sideways without turning after having been joined.
[0045] In FIGS. 7 to 10 a second embodiment is shown. Corresponding
parts are denoted by the same reference numerals as in FIGS. 1 to 6
with the FIG. 2 added in front. In this embodiment the shape of the
top of the hooks 21 and the corresponding downwardly facing inside
of the edge 23 have a different design. Instead of being straight
and angled the sides are configured with horizontal surfaces so
that the hook 21 has a flat top 25 and the inner side a
correspondingly flat abutment surface 26. If the boards should move
relative each other horizontally, they will be guided by both the
top flat contact surface at 25 and 26, and by the lower flat
contact surface at the lower side of the hook 21 and the
corresponding upwardly facing inner side of the edge 23. The
guiding results in that there will be no difference in height
beween the upper surfaces of the boards if the hook 21 should move
relative the recess 211.
[0046] The shoulder 27 is shown straight in the figures but may
also have a rounded upper edge. This will facilitate the joining
but also result in a slightly looser joint.
[0047] The joining is more similar to the conventional method and
is performed as follows:
[0048] Board 2A is laid in place and is to be joined with the next
board 2B.
[0049] Board 2B is laid on the existing ground next to board 2A in
such a way that the heads 24 are located straight in front of the
slots 22 of board 2A and the hooks 21 straight in front of the
shoulders 27. It is now easy to push or knock the boards is
together e.g. by means of a mallet and a block, similar to the case
with the traditional groove and tenon. Thereby the hooks 21 will
pass under the solid edge 23, past the shoulders 27 and into the
recess 211.
[0050] Just when the hook 21 passes under the edge 23 a small
angling or lift will occur between the boards to allow the passage.
However, this occurs automatically and is hardly noticable for the
floor-layer.
[0051] Thereafter, board 2B can be displaced longitudinally just as
before, into its correct position in relation to the walls and the
other floorboards. The heads 24 will thereby also be displaced to a
location below the hooks 21, to form a strong joint. The joint may
be further reinforced by glue, applied e.g. to the top side 25 of
the hooks before mounting board 2B. The shoulders 27 may for
example be about 2 mm long.
[0052] A third embodiment is shown in FIGS. 11 to 14. Corresponding
parts are denoted by the same reference numerals as in FIGS. 1 to 6
with the FIG. 3 added in front. Here, the hook 31 is instead
provided with a downwardly facing projection 315 fitting in a
corresponding groove 316 in the upwardly facing inner side of the
recess 311. The joining is performed in essentially the same way as
in the above second embodiment.
[0053] A fourth embodiment is shown in FIGS. 15 to 18.
Corresponding parts are denoted by the same reference numerals as
in FIGS. 1 to 6 with the FIG. 4 added in front. Here, board 4A is
provided with a protrusion but the slots are not milled through the
protrusion but chamfered as shown at 48. Between the chamfers 48
the protrusion is shaped like a whole hook 41. The protrusion has
an unbroken solid top edge 42 (FIG. 18) with the same flat top 45
as in the second embodiment above. Board 4B has a shape identical
with the second embodiment having a solid edge 43, a recess 411,
heads 44, and shoulders 47. The shoulder 47 is shown straight in
the figures but may also have a rounded upper edge. This will
facilitate the joining but also result in a slightly looser
joint.
[0054] The joining is similar to the method used with the second
and third embodiments and is performed as follows:
[0055] Board 4A is laid in place and is to be joined with the next
board 4B.
[0056] Board 4B is laid on the existing ground next to board 4A in
such a way that the heads 44 are located straight in front of the
chamfers 48 of board 4A and the hook-shaped portions 41 straight in
front of the shoulders 47. It is now easy to push or knock the
boards together by means of a mallet and a block, similar to the
case with the traditional groove and tenon. Thereby the hook-shaped
portions 41 will pass under the solid edge 43, past the shoulders
47 and into the recess 411. The heads 44 do not need a slot but
will slid under the chamfers 48.
[0057] Just when the hook 41 passes under the edge 43 a small
angling or lift will occur between the boards to allow the passage
as before.
[0058] Thereafter, board 4B can be displaced longitudinally just as
before, into its correct position in relation to the walls and the
other floorboards. The heads 44 will thereby also be displaced to a
location below the hooks 41, to form a strong joint.
[0059] The joint may be further reinforced by glue, applied e.g. to
the top side 45 of the hooks before mounting board 4B. The
shoulders 47 may for example be about 2 mm long.
[0060] A fifth embodiment is shown in FIGS. 19 to 22. Corresponding
parts are denoted by the same reference numerals as in FIGS. 1 to 6
with the FIG. 5 added in front. Here, just as in the fourth
embodiment the board 5A is provided with a protrusion where the
slots are not milled through the protrusion but chamfered as shown
at 58. Between the chamfers 58 the protrusion is shaped with a
downwardly facing projection 515 fitting in a corresponding groove
516 in the upwardly facing inner side of the recess 511 as in the
third embodiment. The protrusion has an unbroken solid top edge
with the same shape as in the third embodiment above. Board 5B has
a shape identical with the third embodiment. The shoulder 57 is
shown straight in the figures but may also have a rounded upper
edge. This will facilitate the joining but also result in a
slightly looser joint.
[0061] The joining is performed in essentially the same way as in
the above second embodiment the heads with the grooves 516 sliding
under the chamfers 58.
[0062] After the joining, a small clearance will remain between the
boards A and B in the carrier layer 9, as may be seen from FIG. 2.
The wear layer 8 should preferably not have any remaining gap
between the boards. If the boards, after the joining, should become
warped, or if the underlying floor is uneven, the boards can pivot
in relation to one another about a point located at the top side 5,
25, 45 of the hooks and the underside 6, 26, 46 of the recess 11,
211, 411. It is advantageous for this point to be located as high
as possible, thus avoiding the creation of any gap in the wear
layer if the angle between the boards is changed.
[0063] In the illustrated embodiments, the widths of the hooks and
the intermediate slots or chamfers are the same. This may be varied
as long as the heads have a width corresponding to the slots or
chamfers. The heads (and the hooks) should be about 8 mm wide and
the slots or chamfers (and the shoulders) should be about 10 mm
wide. As the tenon at the short side is 6 mm, the displacement will
be at least 6 mm. If the heads are made wider, e.g. 20 mm, the
total surface locking the boards will be reduced.
[0064] The short sides of the boards of all the embodiments may be
provided with conventional groove-and-tenon joints (or another well
known system). This is illustrated in connection with the first
embodiment in FIGS. 3, 4, 5 and 6 by a groove 10. The corresponding
tenon is located at the other short end and thus is not
visible.
[0065] The illustrated embodiments may be varied e.g. through
modification of the thickness of the wear and carrier layers, the
angles and configuration of the hook, the width and the length of
the boards, etc., all of which should be obvious to a person
skilled in the art. The scope of the invention will only be limited
by the appended claims.
* * * * *