Note: Descriptions are shown in the official language in which they were submitted.
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~C~37~95
- This invention is concerned with a connector for
use in a joint between two members, usually two mutually
perpendicular metal members, and for a completed join-t
incorporating the connector.
5. An example of such a joint is a joint between a
leg and a rail of a table and this joint has to be
I particularly strong if the design of the table does not
include stretchers since the forces on the joint are
substantial as the leg acts like a lever. Consequently
10. these joints are frequently the weakest points in the
construction of a table and it is an aim of this invention
; to provide a connector for use in overcoming this weakness.
According to this invention, a connector for
join~,ing a member having an inwardly lipped, channel-shaped
15. cross-section to a hollow rail comprises a key portion
having means to engage ~ clamping device, and a tongue portion
extending ~way from the key portion and having a ramp surface
and a screw threaded hole at the base of the surface, a head
of the key portion being, in use, arranged to slide between
20. the sides of the channel-shaped member so that a clamping
device engaging the means urges the head of the key
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portion against the lips of the channel to fix
- the connector to the member, the rail sliding over the
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-tongue portion towards the key portion and a
bolt having a counter-sunk head being inserted
through a hole in the rail and being screwed into the
threaded hole, the head of the bolt cooperating with the
5. ramp suface to urge the rail towards the key portion as
. the bolt is screwed into the threade hole to ensure a
rigid joint. ::~
According to another aspect of this invention a
joint between a member having an inwardly lipped, channel-
. 10. shaped cross-section and.a hollow rail comprises a : -:
: connector including a key portion which has a head
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l located between the sides of the channel-shaped member, ~ ::
~ clamp.ing device engaging means on the connector to urge
j . the head of the key portion into locking engagement .
15. with the lips, the connector also including a tongue ~:
portion extending away from the key portion and having
a screw-threaded hole at the base of a ramp surface, .
-l the tongue being inserted into the hollow rail, ..
a hole in the rail being offset from the screw-
~;~ 20. threaded hole in a direction away from the key portion,
.~ the joint also comprising a bolt having a counter- : .
; sunk head which is inserted through the hole into : .
~ the ~eaded hole, so that, as the bolt is tightened
: . .
.~` the combination of the counter-sunk head, the . .
. . .
' 25. offset holes and the ramp surface urge the
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~037~9S
rail towards the key portion to tighten the joint.
Preferably the faces of the head of the key portion
which are directed towards the remainder of the connector
are arranged at an acute angle to the axis of the connector
5. and the inner faces of the lips of the channel-shaped member
have a corresponding inclination, so that, when the clamping
device urges the head of the key portion into engagement
with the lips of the member the correspondingly inclined
faces urge the lips towards one another and so prevent the
; 10. side walls of the channel-shaped member ~rom splaying open
when the joint is stressed.
The head of the key portion may be separate from
J the remainder of the connector and the clamping device may
be arranged to pull the head towards the remainder of the
15. connector so sandwiching the lips of the channel-shaped
member between the head and the remainder of the connec-tor.
l When the head of the key portion of the connector is
.! separate the connector may include a shoulder which acts
as a spacer between the channel-shaped member and the rail~
20. the clamping device clamping the lips of the channel-shaped
member between the head and the shoulder and the counter-
j sunk headed bolt urging the rail against the other side of
I the shoulder. Alternatively the head may be mtegral with
the connector and in this case the clamping device is
~ 25. preferably a grub screw and the means in the connector is
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103709S
preferably an axial threaded bore extending through
- a neck of the connector join ing the head to the remainder
: of the connector so that when the grub screw is
screwed into the bore and tightened~ the grub screw bears
5. against the base of the channel-shaped member an.d urges the
head of the connector against the lips of the channel-
shaped member.
The ramp surface may be flat and inclined in the
; same sense as the inclined surface on the head of the key
10. portion but pre~erably it is a frusto-conical sur~ace which
surrounds the screw-threaded hole in the tongue of the
connector like an enlarged countersink. Preferably the
connector includes at least two threaded holes, each
having a corresponding frusto-conical ramp surface and in
15. this case a counter-sunk bolt is also inserted into the
other threaded hole.
When the head of the key portion of the connector -~
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~i .ts separate the clamping device pre~erably includes a `~
i strip of metal which is placed between a pair of opposed
20. grooves in the remainder of the connector and which
~ includes at least one hole, a bolt passing through the,
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d or each, hole and being screwed into a threaded bore
`~ in the separate key portion of the connector so that as
3; the, or each, bolt is screwed into the key portion the
25. key portion moves towards the remainder of the connector
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to sandwich the lips o~ the channel-shaped member between
the key portion and the remainder of the connector.
This invention is particularly useful when the
two members to be joined are extruded aluminium sections.
When the rail is made from an extruded aluminium section
it has the further advantage that, as the bolt is
tightened in the threaded hole in the connector, the side
wall of the extrusion is deformed by the counter-sunk head
towards the connector, the slight resilience o~ the
, . .
10.aluminium side wall serving to lock the joint together
and lock the bolt in the same way as a spring washer.
The inwardly lipped channel-shaped member may
form a part of an extrusion having a generally arcuate
cross-section or a L-shaped cross-section. In both of
15.these cases where the extrusion is being used as a leg
of a table it preferably includes an inwardly lipped
channel-shaped member along each o~ its edges so that
one rail may be connected to each edge of the extrusion.
¦ The rail may be C-shaped or U-shaped in cross-section but
, 20.it is very much stronger if it has a closed, recta~g~lar
hollow section and thus such a section is pre~erred.
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Examples of connectors and joints in accordance with
our invention which are ~sed to join a leg and a rail of
a table having four legs will now be described with
25.reference to the accompanying drawings, in which:-
Figure 1 is an exploded p~spective view of a first
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example;
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: ~)37~9S
Figure 2 is a horizontal section through the
partly assembled joint; and,
Figure 3 is an exploded perspective view of a
second example.
. 5. The flrst example shown in Figures 1 and 2
comprises a connector 1, a leg 2 and a rail 3. The
connec-tor 1 includes a separate head.
: 4 with its associated clamping device formed by a
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strip 5 and a pair of set screws 6, the clamping device .
10. joining the head 4 to the remainder of the .-.
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connector 1. The remainder of the connector 1 includes
a tongue portion 7 in which two screw-threaded holes 8 .. ~-
l are formed, the holes having countersinks 9 formed in `
one face of the tongue portion 7.
~ 15. The connector 1 also includes a groove 10 which :.
.j is arranged to receive the heads of the set screws 6 and ~
.. . .. .
¦ a pair o~ opposed grooves 11 which are arranged to receive
the strip 5. A pair of drillings 12 are also provided
which are in alignment with the set screws 6 to give
20~ access to ~he heads of the set screws 6 to enable them
~ to be tightened. :.
;.1 The leg 2 includes a channel-shaped member 13 ;
along eaoh of its edges and each channel-shaped member
i 13 includes a pair of inwardly directed lips 14. Internal .
`~ 25. faces I5 on the lips 14 are inclined at an acute angle to . .
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103~9~i
the sides of the channel-shaped member 13. The separate
head . 4 also include~ a pair of inclined faces 16
which are inclined at an acute angle to the axis of the
connector 1 at a correspondi.ng inclination to the inclination
5. of the ~aces 15. The connector 1 also includes a pair of
` ribs 17~projecting towards the head 4 from each
; side of the groove 10.
To assemble this example of the joint the
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head 4 of -the connector is slid between the
10. side walls of the channel-shaped member 13 of the leg 2
until it reaches its required location. The set screws 6
1 are then tightened using an Allen key inserted through the :
^, drillings 12 to fix the connector 1 onto the leg 2. The
.'i ribs 17~are received in the slot between the lips 14 of ~ -
`' 15 the channel-shaped member 13 and this prevents the
i connector at the sides of the groove 10 from splaying .
I open as the set screws 6 are tightened. The cooperating
:l inclined faces 15 and 16 formed on the lips of the channel- .
~¦ shaped member and on the head 4 of the
;. 1 .
20. connector tend to ride over one another to draw the lips
;; 14 o~ the channel-shaped member together and prevent the :
`I channel-shaped member 13 from splaying open when the
joint is stressed. Thus when the set screws 6 have been
fully tightened the connector 1 is locked onto the leg 2
25. in such a way that each of the various.parts of the .
connector 1- cooperate and interfit so that a very secure
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connection is made between the leg 2 and the connector 1.
The rail 3 is of rectangular box-section and
includes a pair of holes 17 which correspond to the screw- ,~
threaded holes 8. To assemble the joint the rail 3 is -,
slid over the tongue portion 7 of the connector 1 anc,when
the end of the rail 3 is butted up against the edge of the
leg 2,the holes 17 are offset from the threaded holes 8
in a direction away from the leg 2 by a distance A as shown
in Figure 2. To fix the rail 3 onto the connector 1 a :,
pair of bolts 18 having counter-sunk heads are inserted
through the holes 17 and into the screw-threaded holes 8.
As the bolts 15 are tightened the counter-sunk heads engage '
the sides of the holes 17 nearest the end of the rail 3 ,
and as the bolts are further tightened their counter-sunk
heads urge the rail 3 against the edge of the leg 2. This
ensures that the rail 3 is fitted tightly against the edge ;
of the leg 2 which gives a neat and clean appearance ~or '',
the completed joint and since it puts the abutting surfaces '
o~ the leg 2 and the rail 3 under co~pression it increases ~ ,
the strength of the completed joint. As the bolts 18 are
tight,ened, the side wall of the rail 3 is deformed into ,,~
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~', the counter-sunk portions 9 of the connector 1, so that, : '
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',! ' the heads of the bolts are accommodated. '
.'J In this example the connector 1, the leg 2 and ;"
~ 25. the rail 3 are all formed'by aluminium extrusions. The
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: ~037~95
; natural sllght resilience of aluminium ensures -that
as the side wall o~ -the rail 3 is deformed it acts as a
compressed sprlng to provide a force urging the rail 3
towards the leg 2 and acts as a spring washer so that
5. the bolts 18 will not work loose.
The second example shown in Figure 3 operates in
esse~ially the same way and, where appropriate, similar
reference numerals have been given to corresponding parts.
In this example the head 4 is rigidly fixed to the remainder
10. of the connector by a neck 19 and the connector 1 is also
provided with a pair of screw-threaded holes 20 which
receive a pair of grub screws 21. To assemble this
example the head 4 is slid into the channel-shaped member 13
on the leg 2 until it is in the required position and then
~, 15. the grub screws 21 are tig~tened until they engage the base
o~ the channel-shaped member 13. Further tightening o~ the
grub screws 21 drives the head 4 away from the base of the
channel-shaped member 13 and causes the inclined ~aces 15
and 16 into enga~ement. Once again the faces 15 and 16 tend
20. to ride over one another and in doing so draw the lips 14 of
. .,
! the channel-shaped members together which prevents the sides
of the channel-shaped members splaying open when the
completed joint is stressed. The rail 3 is then slid over `
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, the tongue portion 7 o~ the connector 1 and connected in an
25. - analagous fashion to the first example.
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1037i~S
The angle subtended by the arcuate leg member 2
is preferably 91~ degrees and in this case when the leg
frame of the table is completed the outside of the joints
between the legs and the rails will be urged together more
`! 5. firmly than the inside of the jolnts. This feature
- contributes to the formation of a close fitting joint
between the leg 2 and the rail 3. The completed Joint in
both these examples gives a very clean and neat outside
appearance and the connector is also completely obscured.
10. When the leg is made from an aluminium extrusion the
resilience of the material coupled with its arcuate section ;
allows the leg to flex to accommodate slight distortions.
' This elastic flexing, means that as -the table is moved in ~
use and put under stress, slight distortions will be `'
' 15. accommodated and the material will not be plastically
~ de~ormed unless the table is subjected to very severe
1 treatment, Thus the completed table will be more robust
~1 than a table with legs having a very rigid cross-section.
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