A concealed fixing retaining clip for roof cladding sheets with profiled ribs
The present invention relates to a clip for
fixing a roof o r other cladding sheet to an underlying
support structure.
The present invention relates particularly,
although b y n o means exclusively, to a clip for fixing a
roof cladding sheet to an underlying roof support
structure.
Typically, roof cladding sheets are roll -formed
from painted o r unpainted steel strip and include one o r
more parallel ribs with opposed sides , pan sections , and
side edge formations that enable the sheets to b e
positioned side b y side in overlapping relationship.
It i s known to secure cladding sheets to an
underlying roof support structure, such a s roof purlins,
b y fastening the sheets directly to the underlying
structure using fasteners, such a s roofing nails and
screws , that pierce the sheets and penetrate the
underlying structure.
It i s also known to secure cladding sheets to an
underlying structure b y using clips that are secured to
the structure b y fasteners and are formed to extend into
the ribs o f the sheets and include retaining members o r
tabs that can engage re-entrant portions o f the ribs and
thereby retain the sheets to the clips. These clip
assemblies are often preferred over nails because they
enable concealed fixing o f cladding sheets to an
underlying structure.
In use, the concealed fixing retaining clips are
secured to an underlying structure a t spaced intervals
related to the spacing between the ribs o f the cladding
sheets. Thereafter, cladding sheets are positioned on the
clips in overlapping relationship by successively pressing
the sheets down onto the clips so that the sides of the
ribs are initially forced outwardly to allow the reentrant
portions of the ribs to pass over the retaining
members and then snap inwardly into engagement with the
retaining members .
There are a number of known concealed fixing
retaining clips . The clips include a clip disclosed in
Australian patent 2003249763 in the name of the applicant
The clip disclosed in the patent is marketed in Australia
under the trade mark KLIPLOK.
The present invention provides an alternative
concealed fixing retaining clip to the KLIPLOK clip
described in Australian patent 2003249763 and to other
known concealed fixing retaining clips .
The above description is not to be taken as an
admission of the common general knowledge in Australia or
elsewhere .
The present invention provides a concealed fixing
retaining clip for fixing a roof or other cladding sheet
to an underlying support structure that is formed from a
resilient material and comprises :
(a) a base;
(b) a pair of side walls that extend from the base;
and
(c) a pair of flanges that define retaining members
for engaging re-entrant portions in the sides of
ribs of cladding sheets , with one flange
defining an arch that extends outwardly and
downwardly from an upper end of one side wall
and the other flange defining an arch that
extends outwardly and downwardly from an upper
end of the other side wall, with the flanges
being a mirror image of each other about a
centreline plane that passes perpendicularly
through the base, and with each flange having a
stiffener on each side of a centreline of the
flange .
The arch of each flange may include a crown and a
downwardly and outwardly sloping wall .
The stiffeners of each flange may be elongate
and extend along an upper part of the side wall and over
the crown of the flange and at least a part of the way
down the sloping wall of the flange.
The stiffeners of each flange may be symmetrical
about the centreline of the flange.
The stiffeners of each flange may be convex in
transverse section when viewed looking at an external
surface of the flange.
Each flange may also include an elongate reverse
stiffener extending along the centreline of the flange.
The reverse stiffener may be concave in
transverse section when viewed looking at an external
surface of the flange.
The stiffeners of each flange may extend towards
but not to an outer end of the flange.
The stiffeners of each flange may stop at least
5 mm from the flange end.
The reverse stiffener of each flange may extend
towards but not to an outer end of the flange.
The reverse stiffener of each flange may stop at
least 5 mm from the flange end.
Each flange end may have a relief in a centre
section of the flange end.
The relief may be a shallow relief.
Each flange end may be a sharp end that contacts
and thereby engages securely the re-entrant portion of one
of the ribs of a cladding sheet when, in use, the cladding
sheet is positioned on the clip.
Each flange end may be outwardly directed. In
other words , the flange ends may not be inwardly turned
towards the side walls of the clip.
Each flange may include the two corner sections
that are folded inwardly and form surfaces that extend
transversely to the outer end of the flange and contact
and thereby engage a re-entrant portion of one of the ribs
of a cladding sheet when, in use, the cladding sheet is
positioned on the clip. This feature increases the
surface area of contact between the flanges and the re¬
entrant portions and thereby makes it possible to minimise
damage to the sheet when it is necessary to remove the
sheet from the clip.
The side walls of the clip converge towards each
other .
The side walls of the clip may be formed so that
they do not contact each other in the as-manufactured form
of the clip and are forced inwardly towards each other or
into contact with each other when, in use, a cladding
sheet is positioned on the clip. This feature makes it
easier to install the clip to an underlying structure
because there is a gap between the clip side walls for
inserting a screw-driver or other suitable tool to
facilitate securing the clip to the underlying structure.
The side walls and the base may be straight sides
so that the side walls and the base define a triangular
structure when viewed from a side of the clip. This
feature contributes to the overall strength and stiffness
of the clip. More particularly, the triangular structure
contributes to the capacity of the clip to withstand
downward loading of the clip, for example when a person
presses down on a rib of a cladding sheet to force the rib
over the clip. In addition, the triangular structure can
accommodate off-centre downward loading that may be
applied to the clip when a cladding sheet is forced down
onto the clip. Specifically, the side walls of the clip
can slide relative to each other in response to off-centre
downward loading and return to the original profile . In
addition, the triangular structure contributes to the
resistance of the side walls to outward movement of the
side walls beyond the as-manufactured positions of the
side walls and therefore is a factor in the clip being
able to resist uplift forces on a cladding sheet.
The side walls may include inturned side edges
that improve the rigidity of the side walls.
The flanges may be relatively long, for example
at least 25% of the height of the clip.
An approach angle of the flanges, described by
each flange and the base of the clip, may be between 40°
and 75°.
The upper ends of the side walls may be shaped
to define a generally circular opening in the asmanufactured
clip to facilitate insertion of a screwdriver
to secure the clip to an underlying structure.
The present invention provides a concealed fixing
retaining clip for fixing a roof or other cladding sheet
to an underlying support structure that is formed from a
resilient material and includes:
(a) a base;
(b) a pair of side walls that extend from the base;
and
a pair of flanges that define retaining members for
engaging re-entrant portions in the sides of ribs of
cladding sheets , with one flange defining an arch that
extends outwardly and downwardly from an upper end of one
side wall and the other flange defining an arch that
extends outwardly and downwardly from an upper end of the
other side wall, with the flanges being a mirror image of
each other about a centreline plane that passes
perpendicularly through the base, and with each flange
having a relief at an end of the flange .
The relief may be a shallow relief.
The side walls may converge towards each other.
The side walls may include inturned side edges
that improve the rigidity of the side walls .
The present invention provides a concealed fixing
retaining clip for fixing a roof or other cladding sheet
to an underlying support structure that is formed from a
resilient material and comprises :
(a) a base;
(b) a pair of side walls that extend from the base,
with the side walls including inturned side
edges that improve the rigidity of the side
walls ; and
(c) a pair of flanges that define retaining members
for engaging re-entrant portions in the sides of
ribs of cladding sheets , with one flange
defining an arch that extends outwardly and
downwardly from an upper end of one side wall
and the other flange defining an arch that
extends outwardly and downwardly from an upper
end of the other side wall, with the flanges
being a mirror image of each other about a
centreline plane that passes perpendicularly
through the base.
The flanges may be relatively long, for exampl
least 25% of the height of the clip.
An approach angle of the flanges , described by
each flange and the base of the clip, may be between 40°
and 75°.
The present invention also provides a clip
assembly which comprises:
(a) an elongate strap; and
(b) a plurality of the concealed fixing retaining
clips described above mounted to an upper surface
of the strap.
The present invention is described further by way
of example with reference to the accompanying drawings , of
which :
Figure 1 is a perspective view of one embodiment
of a clip in accordance with the present invention in an
as-manufactured form;
Figure 2 is a side elevation of the clip shown in
Figure 1 in the direction of the arrow "A" in Figure 1;
Figure 3 is a side elevation of the clip shown in
Figure 1 in the direction of the arrow B" in Figure 1;
Figure 4 is a top view of the clip shown in
Figure 1;
Figure 5 is a bottom view of the clip shown in
Figure 1;
Figure 6 is a side elevation of a section of the
length of one embodiment of a clip assembly in accordance
with the present invention which includes a strap and two
of the clips shown in Figures 1 to 7 in an as-manufactured
form mounted to the strap; and
Figure 7 is a perspective view of a section of
the length of the clip assembly shown in Figure 7 with one
of the clips spaced above the strap and illustrating how
aligned openings in the clip and the strap that facilitate
connecting the clip to the strap.
Figures 1 to 5 illustrate one embodiment of a
clip 3 in accordance with the present invention.
The clip 3 is formed by folding a flat metal,
preferably steel (but not necessarily spring steel) , blank
into the configuration shown the figures .
The clip 3 includes :
(a) a base 5 ;
(b) a pair of side walls 7 that extend from the base
and converge towards each other; and
(c) a pair of flanges 9 that define retaining
members for engaging re-entrant portions of ribs
of cladding sheets , with one flange 9 extending
from an upper end of one side wall 7 and the
other flange 9 extending from an upper end of
the other side wall 7 .
The base 5 includes an opening 63 to facilitate
securing the clip 3 directly to an underlying roof
structure, such as a roof purlin (not shown) or to a strap
29 (see Figures 6 and 7 ) that, in turn, can be secured to
the underlying structure.
The side walls 7 and the base 5 are straight
walls and define a substantially triangular structure in
side view shown in Figure 2 .
The side walls 7 have inturned side edges 61 that
improve the rigidity of the side walls.
In the as-manufactured form shown in Figures 1 to
5 the side walls 7 , whilst converging towards each other,
do not actually contact each other and there is a gap G
(see Figure 2 ) between the side walls 7 at the upper end
of the side walls. However, in use, the side walls 7 are
forced into contact with each other at the upper ends of
the side walls when a cladding sheet is positioned on the
sides walls 7 .
Each flange 9 has a relatively steep approach
angle of the order of between 40° and 75° described by the
flange 9 and the base 5 . With reference to Figure 2 , the
approach angle of the flanges 9 is described by the 2
lines on the left side of the Figure and the angle between
the lines is indicated to be 60°.
The flanges 9 are shaped to form at least part
of an arch 27. More particularly, the arch 27 of each
flange comprises a crown 51 and a downwardly and outwardly
sloping wall 31 . As can be seen in Figure 1 in
particular, the arches 27 are well defined arches. As a
consequence, the flanges 9 take full advantage of the
structural rigidity inherent in an arch structure and
maximises the resistance of the flanges 9 to opening
outwardly in response to roof uplift in high wind
situations.
The sloping wall 31 of each flange 9 terminates
in a sharp lower outwardly facing (as opposed to inwardly
turned) end 37 that forms a contact surface for engaging a
re-entrant portion of one of the ribs of a cladding sheet.
Each flange end 37 has a central relief 31 .
Each flange 9 includes in- turned sections 17 at
the two corners at the lower ends of the flange 9. The
corner sections 17 form contact surfaces that extend
transversely to the contact surface of the outer end of
the flange 9.
Each flange 9 includes a stiffener 41 on each
side of a centreline of the flange. The dotted line X-X
on Figure 4 indicates the centreline of the flanges . The
stiffeners 41 are elongate and extend along an upper part
of the side wall 7 and over the crown 29 of the flange 9
and at least a part of the way down the sloping wall 31 of
the flange 9 . The stiffeners 41 are symmetrical about the
centreline of the flange 9 and are convex in transverse
section when viewed looking at an external surface of the
flange .
Each flange 9 also includes an elongate reverse
stiffener 45 extending along the centreline of the flange
9 . The reverse stiffeners 45 are concave in transverse
section when viewed looking at an external surface of the
flange 9 and extend towards but not to an outer end of the
flange 9.
More particularly, the stiffeners 41 and the
reverse stiffener 45 of each flange 9 stop 5 mm from the
flange end 37 .
It is evident particularly from Figures 1 and 3
that the stiffeners 41 and the reverse stiffeners 45 are
quite pronounced and are significant features of the
structure of the flanges 9 . The stiffeners 41 and the
reverse stiffeners 45 are provided for the same reason as
the well-defined arch structure of the flanges 9 , namely
to maximise the resistance of the flanges 9 to opening
outwardly in response to roof uplift in high wind
situations .
Figure 6 is a side elevation of one embodiment of
a clip assembly in accordance with the present invention
which includes a strap 29 and two clips 3 mounted to the
strap 29. Figure 7 is a perspective view of a section of
the assembly shown in Figure 6 with the clip 3 shown in
the Figure spaced above the strap 29 to reveal a detail of
the assembly.
The strap 29 is a convenient means of fastening
a plurality of the clips 3 to purlins (not shown) at
required spaced intervals along the length of the purlins .
The strap 29 is formed from steel and includes a
flat base 87 and raised lengthwise extending sides 89 that
contribute to the rigidity of the strap. The sides 89 are
in the form of downwardly opening channels. The strap 29
also includes a series of openings 79 at spaced intervals
along the length of the strap. Only one such opening 29
is shown in the Figures . The clips 3 can be secured to
the strap 29 by aligning an opening 63 in a base 5 of a
clip with one of the openings 79 in the strap and using a
suitable fastener (not shown) to attach the clip 3 to the
strap 29.
Many modifications may be made to the preferred
embodiment of the roofing system described above without
departing from the spirit and scope of the present
invention .
By way of example, whilst the embodiment of the
clip 3 includes side walls 7 that converge towards each
other, the present invention is not so limited and extends
to arrangements in which the side walls 7 are not
convergent .
In addition, whilst the embodiment of the clip 3
includes flanges 9 that have elongate reverse stiffeners
45 extending along the centreline of the flange 9 , the
present invention is not so limited and extends to
arrangements that do not include reverse stiffeners 45.

CLAIMS
1. A concealed fixing retaining clip for fixing a
roof or other cladding sheet to an underlying support
structure that is formed from a resilient material and
comprises :
(a) a base;
(b) a pair of side walls that extend from the
base ; and
(c) a pair of flanges that define retaining
members for engaging re-entrant portions in
the sides of ribs of cladding sheets, with one
flange defining an arch that extends outwardly
and downwardly from an upper end of one side
wall and the other flange defining an arch
that extends outwardly and downwardly from an
upper end of the other side wall, with the
flanges being a mirror image of each other
about a centreline plane that passes
perpendicularly through the base, and with
each flange having a stiffener on each side of
a centreline of the flange.
2 . The clip defined in claim 1 wherein the arch of
each flange includes a crown and a downwardly and
outwardly sloping wall and the stiffeners of each flange
are elongate and extend along an upper part of the side
wall and over the crown of the flange and at least a part
of the way down the sloping wall of the flange.
3 . The clip defined in claim 1 or claim 2 wherein
stiffeners of each flange are symmetrical about the
centreline of the flange .
. The clip defined in any one of the preceding
claims wherein the stiffeners of each flange are convex in
transverse section when viewed looking at an external
surface of the flange.
5 . The clip defined in any one of the preceding
claims wherein each flange includes an elongate reverse
stiffener extending along the centreline of the flange.
6 . The clip defined in claim 5 wherein the reverse
stiffener is concave in transverse section when viewed
looking at an external surface of the flange .
7 . The clip defined in claim 5 or claim 6 wherein
the stiffeners and the reverse stiffener of each flange
extend towards but not to an outer end of the flange.
8 . The clip defined in claim 7 wherein the
stiffeners and the reverse stiffener of each flange stop
at least 5 mm from the flange end.
9 . The clip defined in claim 7 or claim 8 wherein
each flange end has a relief in a centre section of the
flange end.
10 . The clip defined in any one of claims 7 to 9
wherein each flange end is a sharp end that contacts and
thereby engages securely the re-entrant portion of one of
the ribs of a cladding sheet when, in use, the cladding
sheet is positioned on the clip.
11 . The clip defined in any one of the preceding
claims wherein each flange includes the two corner
sections that are folded inwardly and form surfaces that
extend transversely to the outer end of the flange and
contact and thereby engage a re-entrant portion of one of
the ribs of a cladding sheet when, in use, the cladding
sheet is positioned on the clip.
12 . The clip defined in any one of the preceding
claims wherein the side walls converge towards each other.
13 . The clip defined in any one of the preceding
claims wherein the side walls include inturned side edges
that improve the rigidity of the side walls .
1 . A concealed fixing retaining clip for fixing a
roof or other cladding sheet to an underlying support
structure that is formed from a resilient material and
includes :
(c) a base;
(d) a pair of side walls that extend from the base;
and
a pair of flanges that define retaining members for
engaging re-entrant portions in the sides of ribs of
cladding sheets , with one flange defining an arch that
extends outwardly and downwardly from an upper end of one
side wall and the other flange defining an arch that
extends outwardly and downwardly from an upper end of the
other side wall, with the flanges being a mirror image of
each other about a centreline plane that passes
perpendicularly through the base, and with each flange
having a relief at an end of the flange.
15. The clip defined in claim 14 wherein the relief
is a shallow relief.
16. The clip defined in claim 14 or claim 15 wherein
the side walls converge towards each other.
17. The clip defined in any one of claims 14 to 16
wherein the side walls include inturned side edges that
improve the rigidity of the side walls .
18 . A concealed fixing retaining clip for fixing a
roof or other cladding sheet to an underlying support
structure that is formed from a resilient material and
comprises :
(a) a base;
(b) a pair of side walls that extend from the base,
with the side walls including inturned side
edges that improve the rigidity of the side
walls ; and
(c) a pair of flanges that define retaining members
for engaging re-entrant portions in the sides of
ribs of cladding sheets , with one flange
defining an arch that extends outwardly and
downwardly from an upper end of one side wall
and the other flange defining an arch that
extends outwardly and downwardly from an upper
end of the other side wall, with the flanges
being a mirror image of each other about a
centreline plane that passes perpendicularly
through the base.
19. The clip defined in claim 18 wherein the flanges
are relatively long, for example at least 25% of the
height of the clip.
20. The clip defined in claim 18 or claim 19 wherein
an approach angle of the flanges , described by each flange
and the base of the clip, is between 40° and 75°.
A clip assembly which comprises:
an elongate strap; and
a plurality of the concealed fixing retaining
clips defined in any one of the preceding claims
mounted to an upper surface of the strap.