Louvre type roof structures

A louvre type roof structure includes a plurality of parallel slats mounted on carrier elements which in turn are mounted on carrier beams such as to permit pivotal displacement of the carrier elements and the slats between a closed position in which the slats are disposed in a roughly coplanar orientation, and an open position in which the slats are disposed in spaced apart generally parallel planes. The carrier elements are secured to the slats by engaging the slats without penetrating the slats, so that each slat is located in a fixed planar orientation relative to the respective carrier. Mounting of the carrier elements to the carrier beams is by means of a pair of mounting levers for each carrier element. One of the pair of mounting levers is a fixed lever securable to a carrier beam in a selected position, and the other lever is a free lever displaceable relative to a carrier beam. Each fixed lever is rotatably attached to its carrier element, and each free lever is fixedly attached to its carrier element to permit pivotal displacement of such carrier element relative to the fixed lever and carrier beam when the free lever is displaced relative to the carrier beam. Each fixed lever has releasable attachment formations for releasably attaching the lever to a carrier beam in a selected position. By way of development, each carrier beam may be in the form of an elongate carrier strip and a beam, the carrier strip being fastened on the beam.

FIELD OF THE INVENTION 
This invention relates to adjustable roof structures, more particularly 
louvre type roof structures. 
BACKGROUND AND PRIOR ART 
The present invention concerns improvements in and modifications of the 
invention (hereinafter referred to as the "earlier invention") entitled 
"Louvre Type Roof Structures" in respect of which the present Applicant 
has filed a U.S. patent application Ser. No. 07/928,789 on Aug. 12, 1992, 
now U.S. Pat. No. 5,306,210 issued Apr. 26, 1994 (hereinafter referred to 
as the "earlier patent"). The complete specification of the main 
application will hereinafter be referred to as the "earlier specification" 
and is incorporated herein insofar as it is relevant, by way of reference. 
The earlier specification describes and claims a louvre type roof structure 
including a plurality of parallel slats mounted on carrier beams extending 
transversely to the slats, in which the slats are mounted on carrier 
elements, which carrier elements are in turn mounted on the carrier beams 
to permit pivotal displacement of the carrier elements and of the slats 
between a closed position in which the slats are disposed in a roughly 
coplanar position, and an open position in which they are disposed in 
spaced apart parallel planes, the carrier elements further being secured 
to the slats by means of securing means engaging the slats without 
penetrating said slats and in such a manner that a slat will be located in 
a fixed planar position relative to a carrier element to which it is 
secured. 
The earlier specification further describes and claims that the carrier 
elements are mounted on the carrier beams by means of mounting levers, a 
pair of mounting levers being provided in respect of each carrier element, 
one of a pair of levers being a fixed lever and being secured to the 
carrier beam in a fixed position, and the other one being a free lever and 
being displaceable relative to the carrier beam, the fixed lever of a pair 
further being rotatably attached to its carrier element and the free lever 
of a pair being fixedly attached to its carrier element to permit pivotal 
displacement of the carrier element relative to the fixed lever and the 
carrier beam when the free lever is displaced relative to the carrier 
beam. 
As explained in the earlier specification, the fixed lever of each pair of 
mounting levers may be mounted on the carrier beam in a fixed generally 
upright position, the fixed lever having a first fixed end, conveniently a 
lower end, fixedly attached to the carrier beam and a second end, 
conveniently an upper end, rotatably attached, such as with a rivet, to 
the carrier element to permit pivotal movement of the carrier element 
relative to the fixed lever. The free lever of each pair may have a first 
fixed end, conveniently an upper end, fixedly attached, such as with 
rivets, to the carrier element, and a lower end which is free to carry out 
reciprocal arcuate movement. The arrangement may be such that reciprocal 
arcuate movement imparted to the free end of the free lever will bring 
about pivotal displacement of the carrier element about a substantially 
horizontal axis, between the aforesaid open and closed positions. Such 
displacement of the carrier elements will bring about corresponding 
pivotal displacement of the slats mounted thereon, between the aforesaid 
open and closed positions. The free ends of adjacent free levers may be 
interconnected by means of a connector rod. 
The first fixed end of the fixed lever is shown in the drawings forming 
part of the earlier specification, to be so fixedly attached to the 
carrier beam by welding. 
The Applicant has now devised certain modifications on improvements to the 
louvre type roof structure as disclosed in the earlier specification, 
which entail significant practical advantages in relation to the 
manufacture of the components for the roof structure, and the construction 
of the roof structure itself. 
SUMMARY OF THE INVENTION 
According to one aspect of the present invention, a fixed lever is provided 
at its first end to be secured to a carrier beam with releasable 
attachment means, by means of which it may releasably be attached to the 
carrier beam in a selected position. If desired, the carrier beam may be 
provided with complementary attachment means, for engaging with the 
attachment means of the fixed lever. 
Thus, the present invention provides a louvre type roof structure including 
a plurality of parallel slats mounted on carrier beams, which structure 
includes 
a plurality of carrier elements on which a said plurality of slats are 
mountable; 
mounting means for mounting the carrier elements on the carrier beams to 
permit pivotal displacement of the carrier elements and the said slats 
mounted thereon between a closed position in which the slats are disposed 
in a roughly coplanar orientation, and an open position in which the slats 
are disposed in spaced apart generally parallel planes; 
securing means for securing the carrier elements to the slats to engage the 
slats without penetrating the slats so that a slat will be located in a 
fixed planar orientation relative to a carrier element to which it is 
secured; 
the said mounting means comprising a pair of mounting levers provided in 
respect of each of said carrier elements, one of a said pair of mounting 
levers being a fixed lever securable to a carrier beam in a selected 
position, and the other one of a said pair of levers being a free lever 
displaceable relative to a said carrier beam; 
a said fixed lever of a pair being rotatably attached to its carrier 
element, and a said free lever of a pair being fixedly attached to its 
carrier element to permit pivotal displacement of such carrier element 
relative to such fixed lever and carrier beam when the free lever is 
displaced relative to the carrier beam; 
a said fixed lever being provided with releasable attachment means for 
releasably attaching the lever to a said carrier beam in a selected 
position. 
As indicated above, a said carrier beam may be provided with complementary 
attachment means, for engaging with the attachment means of a said fixed 
lever. The carrier beam may be arranged to extend transversely to the 
slats. 
It will be appreciated that the provision of fixed levers with releasable 
attachment means as envisaged by the present invention, entails the 
advantage that such levers may be attached to the carrier beams as 
required on site, without the need for sophisticated tools and equipment, 
such as welding equipment. Furthermore, to ensure accurate alignment of 
the carrier elements, and consequentially accurate closure of the louvre 
slats, the position of the fixed levers on the carrier beams may be 
adjusted on sited, as required. 
The attachment means on the fixed lever and the complementary attachment 
means on the carrier beam may be complementary male and female engagement 
formations, e.g. complementary tongue-and-groove formations, complementary 
hook-and-groove formations, or the like. For example, the fixed lever may 
be provided with a pair of spaced protruding tongue formations, and the 
carrier beam may have a pair of spaced grooves, the spacing of the tongue 
formations being equidistant to the spacing of the grooves to permit the 
tongue formations to be releasably engaged within the grooves. The 
arrangement may be such that the fixed lever may resiliently be deformed 
to engage the tongue formations within the grooves. 
The configuration and dimensions of the complementary male and female 
engagement formations may be such as to withstand a disengagement or 
lifting force of up to about 100 kg/m.sup.2. 
In one embodiment, the fixed lever may be of generally L-shaped 
configuration, having an upright arm to be arranged in generally vertical 
orientation in use, and a transverse limb to be arranged in generally 
horizontal orientation in use. The protruding tongue formations may be a 
pair of spaced and in use generally downwardly protruding tongue 
formations provided on the transverse limb, e.g. on the underside thereof. 
A pair of complementary spaced grooves may be provided on an in use 
generally upwardly directed face of the carrier beam, so that a fixed 
lever may be mounted on a carrier beam so that the upright arm is arranged 
in a generally vertical orientation when the tongue formations on the 
transverse limb of the lever are engaged in the complementary grooves in 
the carrier beam. 
In an alternative embodiment of the carrier beam, a pair of laterally 
facing grooves may be provided in opposed and in use generally outwardly 
directed lateral faces, e.g. on side walls of the carrier beam, in the 
proximity of the top wall, preferably located in lateral regions of 
increased thickness where the top wall meets the side walls. In this case, 
fixed levers of modified configuration will be provided, each having a 
pair of angled lip formations to extend around the edges of the top wall 
and engage with the grooves provided in the side walls of the carrier 
beam. For example, generally L-shaped fixed levers of modified design may 
be provided, each lever having an upright arm in use to be arranged in 
generally vertical orientation, and a transverse limb in use to be 
arranged in generally horizontal orientation, a pair of spaced and opposed 
and in use generally downwardly and inwardly angled lip formations being 
provided on the transverse limb; the arrangement being such that the fixed 
lever may be arranged with its transverse limb straddling the carrier beam 
and with the lip formations engaging within the grooves to releasably 
secure the fixed lever to the carrier beam. 
The lip formations may be provided on the underside of the transverse limb. 
Instead, the lip formations may be provided on a pair of spaced and 
opposed depending flanges formed on the transverse limb, the flanges being 
configured in use to extend generally downwardly adjacent opposed side 
walls of the carrier beam. At least one of the flanges may be formed to 
have sufficient resilience to allow the flange to be deformed resiliently, 
to engage the lip formation in the appropriate lateral groove provided in 
the side wall of the carrier beam. 
In yet another embodiment, the complementary attachment means of the fixed 
levers and the carrier beam may comprise an attachment flange formation 
provided on a fixed lever, configured to be placed against a wall of the 
carrier beam, and securing means, such as a rivet or a screw, for securing 
the attachment flange of the lever to the wall of the carrier beam. A 
fixed lever may thus have an upright arm and a pair of perpendicular 
flanges, to be placed in abutting relationship against two adjacent walls 
of a carrier beam, e.g. the top wall and a side wall. Corresponding tapped 
holes may be provided in the carrier beam and one or both of the abutting 
flanges, to receive a securing screw. 
According to a further feature of the invention, the carrier beams and the 
fixed levers, as well as some or all of the other components of the roof 
structure, may conveniently be made of an aluminium-based material, e.g. 
an aluminium alloy. The use of an aluminium alloy material provides 
important practical advantages, such as a reduction in overall mass of the 
components and thus of the roof structure, improved resistance to 
corrosion e.g. rust, enhanced appearance, and more importantly, beneficial 
mass manufacturing possibilities, etc. 
Making some of the components of an aluminium alloy also involves the 
possibility of making at least some components by an extrusion process, 
thereby enabling novel configuration designs to be used. Aluminium-based 
materials are, however, difficult to weld. Accordingly, the use of a 
releasable attachment means as envisaged in the present invention has been 
found to be particularly advantageous in respect of aluminium-based 
components, for mounting the fixed levers on the carrier beams. 
According to another aspect of the invention, a carrier beam may be an 
extruded component of an aluminium-based material, preferably having a 
cross-sectional profile to provide optimum strength, particularly bending 
strength, in relation to quantity of material used. A carrier beam may 
thus be a hollow, tubular extruded component, having a generally 
rectangular exterior configuration with a pair of opposed side walls and 
opposed top and bottom walls, the side walls being of substantially 
greater height than the width of the top and bottom walls and of 
substantially smaller wall thickness. 
In a particular embodiment, a carrier beam of aluminium-based material in 
the form of an extruded hollow tubular member as described above, may have 
side walls of about 90 mm in height and about 2,5 mm wall thickness, and 
may have a bottom and top wall of about 38 mm in width, the top and bottom 
walls having a wall thickness of about 9 mm. The top wall may preferably 
be of varying thickness, having a central region of reduced thickness and 
lateral regions adjacent the side walls of increased thickness. The 
thickness of the central region may be about 7 mm and that of the lateral 
regions about 12-14 mm. 
The grooves in the carrier beam for receiving the male engagement 
formations on the fixed levers, may be provided in the lateral regions of 
the top wall of the carrier beam, ie regions having increased thickness. 
The grooves may extend longitudinally along the length of the carrier 
beam. 
According to a further aspect of the invention, the fixed levers may be cut 
from an elongate component configured to permit a plurality of fixed 
levers to be cut therefrom, e.g. along transversely orientated cutting 
lines. The elongate component may be an extruded component of an 
aluminium-based material. The extruded component may be of generally 
L-shaped configuration, having a first continuous limb to constitute the 
upright arms of a plurality of fixed levers, and a second continuous limb 
arranged at a suitable angle to the first limb to constitute the 
horizontal arms of a plurality of fixed levers to be cut from the 
component, e.g. along cutting lines disposed generally perpendicular to 
the longitudinal dimension of the extruded component. Continuous male 
engagement formations may be provided on the transverse arm, e.g. 
continuous protruding tongue formations, or continuous angled lip 
formations, as the case may be, or continuous perpendicular flanges may be 
provided, to constitute the attachment means on the levers cut from the 
component. 
In similar manner as described more fully in the earlier patent, a 
plurality of pairs of mounting levers may be provided in respect of a 
carrier beam, the fixed levers of each pair being attachable to the 
carrier beam in spaced relationship at suitable intervals along its 
length, to carry a plurality of correspondingly spaced carrier elements. 
The free ends of the free levers of each pair of mounting levers operable 
on a carrier beam may be interconnected by means of an elongated 
connector; the arrangement being such that reciprocal displacement of the 
connector imparts reciprocal arcuate movement of the free levers to bring 
about pivotal displacement of the carrier elements and thus of the slats 
mounted on the carrier elements. 
As further described in the earlier patent, a plurality of carrier beams 
may be provided adjacent one another in spaced parallel relationship such 
that pairs of mounting levers on adjacent carrier beams are substantially 
aligned, and a rotation rod may be provided to extend between selected 
aligned pairs of mounting levers on adjacent carrier beams, the rotation 
rod being secured to the selected mounting levers in such a manner that 
rotational motion of the rod around its longitudinal axis will bring about 
arcuate movement of the free levers of the aligned pairs of mounting 
levers, thereby imparting linear displacement to the connectors 
interconnecting the free levers carried on a carrier beam, so as to bring 
about pivotal displacement of the interconnected free levers, the carrier 
elements and thus of the slats. For mounting the rotation rod, the fixed 
lever of a selected pair of mounting levers is modified to support the 
rotation rod so as to permit rotational motion of the rod, and the free 
lever of the selected pair of mounting levers is modified to support the 
rotation rod in fixed relationship and to carry a carrier element, so as 
to transfer rotational motion of the rotation rod as pivotal movement to 
the carrier element. 
As mentioned in the earlier specification, the earlier invention envisaged 
the provision of prefabricated carrier beams of suitable length, having 
mounted thereon a plurality of fixed levers and associated free levers, 
the carrier beam if necessary to be cut to the required length on site, 
where the roof structure is to be constructed. The provision of 
prefabricated components are also envisaged in the context of the present 
invention, including for example carrier beams of suitable length and a 
plurality of fixed lever components to be attached on site to the carrier 
beams, e.g. by means of the complementary tongue-and-groove attachment 
means, or the lip-and-groove attachment means, at suitable intervals along 
the length of the carrier beams. It will be appreciated that such 
prefabricated carrier beams and the accompanying unattached but readily 
attachable lever components in accordance with the present invention, may 
be packed and transported more conveniently than the prefabricated carrier 
beams with affixed levers as envisaged in the earlier specification. 
It will further be appreciated that the fixed levers, having readily 
engageable engagement means, may be mounted on the carrier beams by 
unskilled persons and without the use of additional tools or equipment, 
e.g. without holes having to be drilled and rivets inserted, or without a 
welding joint having to be effected. The invention is thus suitable to be 
provided in the form of do-it-yourself construction kits. 
According to the invention, there is thus provided a kit for constructing a 
louvre type roof structure as described above, the kit including a 
plurality of carrier beams of suitable length; and one or more composite 
units each of which unit comprises a plurality of carrier elements on 
which a plurality of slats are mountable, each carrier element carrying a 
pair of mounting levers, one of such pair of mounting levers being a fixed 
lever attachable to a carrier beam in a selected position, and the other 
one of such pair being a free lever displaceable relative to a said 
carrier beam; the fixed levers of each pair being rotatably attached to 
its carrier element, and the free levers of each pair being fixedly 
attached to its carrier element; the free levers of each pair further 
being interconnected by means of an elongated connector, and the fixed 
levers of each pair having releasable attachment means for releasably 
attaching the fixed levers to a carrier beam in selected positions. The 
kit may also include a tool to determine the positioning and placement of 
a plurality of fixed levers on a carrier beam, the tool comprising an 
elongated placement member having key markings at selected spaced 
intervals along its length, to permit the placement member to be placed 
along a carrier beam and fixed levers to be releasably attached to the 
carrier beam with reference to the key markings. 
The placement member may be a rod of angled configuration, ie having a pair 
of longitudinally extending flanges disposed at right angles to one 
another to enable the member to be positioned to straddle the carrier 
beam. The key marks may be cut-outs provided in one or both of the 
flanges, at selected intervals, whereby the levers to be attached may be 
placed in the cut-outs. 
According to a further aspect of the invention, the free lever of a pair of 
mounting levers as described herein, instead of being a separate lever 
element secured to a relevant carrier element and a connector, may be 
formed integrally with a carrier element. Thus, a carrier element may be 
formed with an elongated extension portion to constitute a said free 
lever, the extension portion being of such longitudinal dimensions to 
enable the extension portions of a plurality of carrier elements to be 
interconnected by a connector in a manner to permit displacement of the 
connector to bring about unimpaired displacement of the carrier elements 
and slats mounted thereon between a closed and an open position. 
The extension portion may be formed integrally when the carrier element is 
formed, and may be of a suitable shape and configuration. If desired, the 
extension portion may have a reinforcing rib or a deformation to impart 
rigidity to the free lever formed by such extension portion. 
It will be understood that a selected pair of mounting levers on a 
composite unit may be modified to support a rotation rod so that 
rotational motion of the rod around its longitudinal axis will bring about 
displacement of the free levers, the connectors, and the carrier elements, 
as described more fully in the earlier specification.

DETAILED DESCRIPTION 
Referring to FIGS. 1 to 16 of the drawings, in which parts corresponding to 
similar parts in the main specification have as far as possible been 
indicated with similar reference numerals, a louvre type roof construction 
according to the invention comprises a plurality of parallel louvre slats 
one of which is shown as 10, mounted on carrier beams one of which is 
shown as 12, extending transversely to the slats 10, by means of carrier 
elements 14. The carrier elements 14 are as described in the main 
specification. The carrier elements 14 are mounted on the carrier beams 12 
by means of pairs of mounting levers comprising a fixed lever 16 and a 
free lever 18. 
In the embodiment shown in FIGS. 1-5, a fixed lever 16 may be of generally 
L-shaped configuration, having an upright arm 16.3 to be arranged in 
generally vertical orientation in use, and a transverse limb 16.4 to be 
arranged in generally horizontal orientation in use. The upper region 16.5 
of the fixed lever is rotatably secured to a carrier element 14 at 16.2, 
e.g. by means of a rivet (not shown). It will be noted from FIG. 2 that 
the upper region 16.5 is offset relative to the rest of the upright arm 
16.3, to enable the free lever 18 to be rotatably secured to the fixed 
lever 16 at 16.2 (as described more fully in the main specification), with 
adequate clearance, as depicted in FIG. 2. 
As described in the main specification, the free levers 18 are 
interconnected at their lower ends by a connector rod 22, so that 
reciprocal movement of the connector 22 in the direction of the arrow B in 
FIG. 1 will bring about pivotal movement of the carrier elements 14, and 
thus also of the louvre slats 10, in the direction of the arrow A in FIG. 
1. 
The fixed lever 16 is provided with releasable attachment means in the form 
of a pair of spaced and protruding tongue formations 16.6 on the underside 
of the transverse limb 16.4. It will be noted that the tongue formations 
16.6 are directed inwardly towards one another, to engage securely within 
complementary groove formations 12.6 provided on the carrier beam, as 
described more fully below. 
The carrier beam 12 comprises a hollow tubular extruded component, 
preferably of an extrudable aluminium-based material, which is generally 
rectangular in cross-section, as is evident from FIGS. 2 and 3, having 
opposed side walls 12.1, 12.2 and a top wall 12.3 and bottom wall 12.4. It 
will be observed that the height of the side walls 12.1, 12.2 is 
substantially greater then the width of the top and bottom walls 12.3, 
12.4. The side walls 12.1, 12.2 may for example, have a height of about 90 
mm, and the width of the top and bottom walls 12.3, 12.4 may be about 38 
mm. Further, it will be noted that the thickness of the side walls 12.1, 
12.2 is substantially less than that of the top and bottom walls 12.3, 
12.4. The thickness of the side walls 12.1, 12.2 may, for example, be 
about 2-5 mm while that of the top and bottom walls 12.3, 12.4 may be 
about 7-9 mm or more. It will be noted that the thickness of the top wall 
12.3 increases from the middle outwardly, from a thickness of about 7 mm 
in the middle region to lateral regions of increased thickness of about 12 
mm. This configuration enables carrier beams 12 of optimal strength and 
carrying capacity, particularly bending strength, to be made with a 
minimal mass of aluminium-based material. 
In the top wall 12.3, on the outside face thereof, there is provided a pair 
of longitudinally extending groove formations 12.6 within which the tongue 
formations 16.6 of the fixed levers 16 are engageable. It will be noted 
that the grooves 16.6 are angled and are configured to be directed 
inwardly, ie towards one another, to be complementary to the configuration 
of the tongue formations 16.6. 
By deforming the transverse limb 16.4 of the fixed lever 16 slightly, in 
the direction of the arrow C in FIG. 2, the tongue formations 16.6 of the 
fixed lever 16 may be snapped into the grooves 12.6 of the carrier beam 
12, to secure the fixed lever 16 fixedly to the carrier beam 12. The 
deformation should preferably be within the elastic capacity of the fixed 
lever 16, which capacity is inter alia determined by the thickness of the 
transverse limb 16.4, to bring about a resilient deformation with a return 
to its original shape, and to avoid a plastic deformation which will bring 
about permanent loss of shape. It will be appreciated that this provides a 
quick and convenient method of attaching the fixed levers 16 to the 
carrier beam 12, without requiring a welding procedure. 
If necessary, e.g. if the engagement between the tongue formations 16.6 and 
the grooves 12.6 should for any reason, e.g. wear of the die former used 
in the extrusion process, become less effective, further securing means 
may be provided, such as an adhesive bonding material, screws or rivets, 
or the like. 
Reverting now more particularly to FIG. 4, there is illustrated how the 
fixed levers 16 may be made from an elongate extruded component 116, 
conveniently also of an aluminium-base material, and having a suitable 
profile to present an upright arm 116.3 and a transverse limb 116.4. 
Longitudinally extending tongue formations 116.6 are provided on the 
underside of the transverse limb 116.4, to constitute the tongue 
formations 16.6 on the fixed lever 16. A plurality of fixed levers 16 will 
in practice be cut from a component 116, each lever 16 conveniently having 
a width of about 20 mm. 
It will further be noted from FIGS. 2 and 3, that the carrier beam 12 is 
provided with a slight bevelled or cut-away face 12.5 on the upper face 
thereof, adjacent a groove formation 12.6. The purpose of this bevelled 
face 12.5 is to present a gap between the carrier beam 12 and the fixed 
lever 16, shown as 117 in FIG. 2, into which a suitable tool, such as a 
screw driver, may be inserted to disengage the fixed lever 16 from the 
carrier beam 12, to remove the lever. This may be necessary when it is 
desired to adjust the position of a fixed lever 16. It will thus be 
appreciated that, although a lever 16 in use will be firmly attached to 
the carrier beam 12, it will in fact be releasably attached, to permit its 
removal. 
In FIG. 5 there is illustrated the manner in which a carrier beam 12 may be 
mounted against a wall or other support surface (not shown). As described 
in the main specification, the carrier beams 12 of a roof structure may 
themselves be supported on support beams which are disposed transversely 
to the carrier beams; such a support beam is shown as 24 in FIG. 1 of the 
accompanying drawings. A support beam 24 is also a hollow extruded tubular 
component, again preferably of an aluminium-based material, and of 
rectangular cross-sectional shape having side walls 24.1, 24.2 and a top 
and bottom wall 24.3 and 24.4 respectively. The support beam 24 is of such 
cross-sectional dimensions, that a carrier beam 12 is receivable within a 
support beam 24, as depicted in FIG. 5. 
Reverting now to FIG. 5, a carrier beam 12 may be mounted with the aid of a 
short length of a support beam 24 the dimensions of which are such that 
the end portion of the carrier beam 12 is receivable within the piece of 
support beam 24. A mounting plate 124 is provided, and complementary holes 
24.5 and 124.5 are provided in the piece of support beam 24 and the 
mounting plate 124 respectively, so that the mounting plate 124 may be 
secured to the piece of support beam 24 by means of screws. The mounting 
plate has further holes 124.1, 124.2 by means of which it may be secured 
to a wall or other support surface (not shown) to mount the carrier beam 
12. 
As illustrated, the support beam 24 is also provided with longitudinally 
extending groove formations 24.6, so that it may itself be used as a 
carrier beam where a sturdier roof construction is required. 
In the main specification there is further described how reciprocal 
displacement of the free levers 18 and the connector 22 is brought about 
by means of a rotation rod 30 operatively connected to the fixed and the 
free levers 16, 18. To support the rotation rod 30, the levers 16, 18 
occurring in the relevant position have to be modified. The present 
invention provides a variation of the means used for modifying the fixed 
lever 16 and the free lever 18, as will be described below. 
FIG. 6 depicts a modified rod support element 226 comprising an open 
channel-shaped bracket 226.1 shaped and dimensioned to fit around the 
upper portion 16.5 of the upright arm 16.3 of a fixed lever 16, and a ring 
226.2 of diametral dimensions to receive the rotation rod 30. In use, the 
upper end of the upright arm 16.3 of the relevant fixed lever 16 will be 
cropped sufficiently for the lever to maintain its correct height when the 
rod support element 226 is mounted thereon. The rod support element 226 is 
then mounted on the cropped upright arm 16.3 with the channel-shaped 
bracket 226.1 extending around the cropped upper end, and the bracket 
226.1 is secured to the arm 16.3, e.g. by pinching the bracket 226.1. 
Alternatively, the bracket 226.1 may be formed with a protuberance 226.3, 
and the lever arm 16.3 may be formed with a complementary depression (not 
shown), e.g. when the arm 16.3 is cropped, to enable interlocking 
engagement between the protuberance 226.3 and the depression to take place 
when the bracket is mounted on the cropped upright arm 16.3. 
FIG. 7 depicts a modified rotation rod support element 228 to be 
substituted for a free lever 18 in the relevant position, the element 228 
comprising a ring part 228.1 to receive the rotation rod 30, and a lever 
part 228.2 to replace and serve as the free lever 18. On the ring part 
228.1 is provided a plate 228.3 on which the carrier element 14 is mounted 
by means of rivets through apertures 228.4; and an aperture 228.5 is 
provided for lockingly securing the ring part 228.1 to the rotation rod 30 
by means of a grub screw 228.6. 
It is an advantage of the modifying means as depicted in FIGS. 6 and 7 and 
described above, that a suitable number of pairs of the elements 226 and 
228 may be threaded onto the rotation rod 30 (the number corresponding to 
the number of carrier beam assemblies to be serviced), whereupon the 
rotation rod 30 may be lowered onto the roof structure, and the threaded 
on elements may be secured to the cropped fixed levers 16 and the 
connector 22 in respect of each carrier beam 12. This facilitates 
installation of the rotation rod 30. 
Reverting now to FIGS. 8, 9 and 10, there are illustrated variations of the 
fixed lever 16. The fixed lever depicted in FIG. 8 is indicated generally 
as 216 and comprises an upright arm 216.3 and a transverse limb 216.4. The 
upper part 216.5 of the upright arm 216.3 is again off-set relative to the 
rest of the arm 216.3, and an aperture 216.7 is provided for connection of 
the fixed lever 216 to a free lever 18 and to a carrier element 14. On the 
underside of the transverse limb 216.4 there is provided a pair of spaced 
and downwardly angled lip formations 216.6 which are shaped to extend over 
and around the top edges of a modified carrier beam 212 to engage within 
lateral groove formations 212.6 provided in the side walls 212.1, 212.2 of 
the carrier beam 212. It will be observed that the modified carrier beam 
212 is otherwise similar to the carrier beam 12 depicted in FIGS. 1-3. 
The modified fixed lever 316 depicted in FIG. 9 again has an upright arm 
316.3 with an off-set upper port 316.5 and an aperture 316.7. Instead of a 
transverse limb, the lever 316 has a pair of perpendicular attachment 
flanges 316.4 and 316.5, to be arranged to straddle a modified carrier 
beam 312. The flange 316.4 is attached to the beam 312 by means of a screw 
312.6. It will be observed that the carrier beam 312 is again very similar 
in shape and configuration to the beam 12 depicted in FIGS. 1-3, except 
that it does not have the groove formations. 
The modified fixed lever 416 depicted in FIGS. 10-13 and 15 comprises an 
upright arm 416.3 and a transverse limb 416.4. The upper part 416.5 of the 
upright arm 416.3 is again slightly off-set, as explained above, and an 
aperture 416.7 is provided for connection of the fixed lever 416 to a free 
lever 418 and to a carrier element 414. The transverse limb 416.4 is 
formed at its free end to present a generally inverted V-formation 416.2 
having an inwardly directed lip formation 416.1 at its extremity. It will 
be appreciated that the V-formation will display resilience in practice, 
to allow it to be deformed resiliently in the direction of the arrow D in 
FIGS. 10 and 11. 
At the opposed end of the transverse limb 416.4 there is provided a 
depending flange 416.11 with an inwardly directed lip formation 416.8 at 
its extremity. On the underside of the transverse limb 416.4 there is also 
provided a pair of spaced downwardly directed ridge formations 416.9, 
416.10 for a purpose to be described below. 
The lever 416 is shown mounted on a carrier beam 412, having side walls 
412.1, 412.2 and a top wall and bottom wall 412.3, 412.4. The carrier beam 
412 is generally of the same configuration and features as the carrier 
beam 12, except that the female attachment means is in the form of grooves 
412.6 provided on the outside of the side walls 412.1, 412.2 near the top 
wall 412.3. It will be observed that the grooves 412.6 occur in the 
lateral regions of increased thickness, as described above. 
In use, the lever 416 is mounted on the carrier beam 412 by first inserting 
the lip formation 416.8 in the appropriate groove 412.6, and then 
resiliently deforming the V-shaped formation 416.2 in the direction of the 
arrow D to engage the transverse limb 416.4 and the V-shaped formation 
416.2 around the upper part of the carrier beam 412 and to engage the lip 
formation 416.1 into the appropriate groove 412.6. To bring the lip 
formation 416.1 into proper and secure engagement with the groove 412.6, 
it may be necessary to tap the V-shaped formation 416.2 and the transverse 
limb 416.4, such as with a hammer, in the direction of the arrow E shown 
in FIG. 11. 
The ridge formation 416.9 abuts against, and bears against, the upper face 
of the top wall 412.3 of the carrier beam 412, to provide a secure and 
sturdy arrangement, by placing the flange 416.11 under tension and drawing 
the lip formation 416.8 more securely into the groove 412.6. It will be 
noted, as depicted in the drawings, that the portion of the transverse 
limb 416.4 adjacent the flange 416.11 and the flange 416.11 itself, are of 
greater wall thickness than the rest of the transverse limb 416.4 and the 
V-shaped formation 416.2. The reason for this is that the smaller wall 
thickness of the V-shaped formation 16.2 and the adjacent portion of the 
transverse limb 416.2 and the adjacent portion of the transverse limb 
416.4 imparts greater resilience and deformability to those parts, to 
facilitate engagement of the lip 416.1 within the groove 412.6. On the 
other hand, the greater wall thickness of the other aforesaid parts 
improves the load-bearing capacity of those parts. 
The ridge formation 416.10 likewise abuts against, and bears against, the 
upper face of the top wall 412.3 of the carrier beam 412, particularly 
during engagement of the lip 416.1 within the groove 412.6. The ridge 
formation 416.10 would thus prevent excessive deformation of the 
transverse limb 416.4 and the V-shaped formation 416.2. 
In practice, the transverse dimensions of the transverse limb 416.4, ie 
from the flange 416.11 to the V-shaped formation 416.2, may also be 
slightly smaller than the transverse dimensions of the top wall 412.3 of 
the carrier beam 412, to ensure a secure engagement and grip of the lip 
formation 416.1, 416.8 within the grooves 412.6. 
As explained before, and as illustrated in FIG. 15, the Applicant envisages 
the provision of a kit for constructing a louvre type roof structure 
according to the invention. Such a kit would include a plurality of 
carrier beams one of which is shown as 412, selected on the basis of 
suitable length, and a plurality of composite units one of which is shown 
as 415. Suitable composite units 415 will in practice be selected on the 
basis of the number of carrier elements 414 provided thereon, the selected 
composite units together to provide the required number of carrier 
elements 414 to carry the required number of slats to cover the roof area. 
A composite unit 415 thus comprises a plurality of carrier elements 414 on 
which slats will be mountable, and a plurality of pairs of mounting levers 
416, 418. The free levers 418 are interconnected by a connector 422, while 
the fixed levers 416 are secured to the carrier elements 414 in the manner 
described above. 
To construct a roof structure, the carrier beams 412 will be mounted as 
explained more fully in the main patent, and the fixed levers 416 will be 
releasably attached to the carrier beams 412 in suitably selected 
positions, in the manner described above. 
To determine the positioning and placement of the fixed levers 416 on the 
carrier beam 412, suitable key marks (not shown) may be provided on the 
carrier beam 412; or instead, a placement member (not shown) may be 
provided having suitably spaced key markings along its length, with the 
aid of which the fixed levers may be positioned. 
It will be noted that a composite unit 415 includes modified mounting 
levers for mounting a rotation rod (not shown in FIG. 15, but shown as 30 
in FIG. 1). The modified mounting levers include a modified free lever 
419, and a modified fixed lever 417. The modified fixed lever 417 is 
illustrated in FIG. 14. It will be observed that it is configured 
generally similarly to a fixed lever 416, being cut from the same 
extrusion, but is of greater width to allow for an aperture 417.7 to 
accommodate a rotation rod. Since the lever 417 has features corresponding 
to the fixed lever 416, including a flange 417.11 and lip formation 417.8, 
and a V-shaped formation 417.2 and lip formation 417.1, and ridges 417.9 
and 417.10, it can be engaged with the carrier beam 412 in similar manner 
to the fixed lever 416. 
Referring now to FIG. 16, there is depicted an alternative embodiment of 
the invention, in which a free lever 518 is formed integrally with a 
carrier element 514. The carrier element 514 is thus of modified 
configuration, being formed with an elongated extension portion to 
constitute the free lever 518. A plurality of such free levers 518 may 
then be interconnected by means of a connector 522, in a manner similar to 
that shown in FIG. 15, to permit displacement of the connector 522 without 
interfering with the displacement of the carrier elements 514 (and the 
slats mounted thereon, not shown) between the open and closed positions. A 
fixed lever 516 of similar configuration as the lever 416 shown in FIG. 
15, is rotatably secured to the carrier element 514, as described above. 
The fixed lever 516 is in turn releasably attached to a carrier beam 512, 
as described above, to construct a roof structure. 
FIGS. 17 to 22 of the drawings show different applications or embodiments 
of a development of the applications or embodiments described above. For 
ease of perception, the development is illustrated in each of the 
respective FIGS. 17 to 22 in respect of applications or embodiments 
already illustrated and described above, and the same or similar reference 
numerals are conveniently used. For convenience, the information 
indication in the brief description of the drawings, is repeated, namely 
that 
FIG. 17 is analogous to FIG. 2; 
FIG. 18 is analogous to FIG. 8; 
FIG. 19 is analogous to FIG. 9; 
FIG. 20 is analogous to FIG. 10; 
FIG. 21 is analogous to FIG. 15; 
FIG. 22 is analogous to FIG. 16. 
The development is basically to provide an elongate, generally flat plate 
embodying the mounting formations provided at the top of the respective 
beam in the corresponding undeveloped embodiment or application to mount 
the respective fixed lever. This elongate flat plate can then be affixed 
in any convenient manner to an existing substrate such as an existing 
beam, thereby to mount the louvre type roof structure in accordance with 
this invention on an existing substrate. This has the important advantage 
that modular units can be supplied, in different lengths, to enable a 
louvre type roof structure in accordance with the invention to be erected 
in modular fashion on an existing substrate. 
Even if an existing substrate does not exist, it is advantageous that a 
substrate can be provided in virtually any convenient or traditional 
manner and that the louvre type roof structure can be superimposed on such 
a substrate in modular fashion. 
More specifically, with reference to FIG. 17, the fixed lever 16 of FIG. 2 
is mounted in a fashion already described with reference to FIG. 2 on an 
elongate, generally flat plate 1012.3 corresponding to the upper portion 
12.3 of the beam 12 of FIG. 2. 
The elongate generally flat plate 1012.3 can be affixed in any convenient 
manner to an existing substrate, e.g. in the form of a timber beam 1012. 
To facilitate fixing, an elongate recess or groove 12.7 is provided in the 
plate 1012.3 such that nails, screws, or the like which have heads can be 
accommodated within the groove 12.7 without the heads protruding beyond 
the upper plane of the plate 1012.3. 
With reference to FIG. 18, the fixed lever 216 of FIG. 8 is releasably 
mounted on an elongate, generally flat plate 2212.3 corresponding to the 
upper portion 212.3 of the beam 212 of FIG. 8. 
In the embodiment of FIG. 18, the plate 2212.3 can be affixed in any 
convenient manner, e.g. by screws, nails or the like to a beam 2212 which 
is shown to be of timber in FIG. 18. 
To facilitate mounting, a longitudinal recess or groove 212.7 is provided 
in the top of the plate 2212.3 to ensure that heads of the fasteners do 
not extend beyond the top plane of the plate 2212.3. 
Similarly, with reference to FIG. 19, the lever 316 of FIG. 9 is releasably 
screwed by means of the screw 312.6 to an elongate flat plate 3312.3 
corresponding to the upper portion 312.3 of the beam 312 of FIG. 9. In 
this case, the plate 3312.3 is screwed or otherwise fixed to an existing 
hollow section beam 3312 of steel. A groove 312.7 in the top of the plate 
3312.3 facilitates neat mounting such that heads of fastener elements do 
not protrude. 
Similarly, with reference to FIG. 20, the lever 416 of FIG. 10 is 
releasably mounted on an elongate generally flat plate 4412.3 
corresponding to the upper portion 412.3 of the beam 412 of FIG. 10. In 
this embodiment, the plate 4412.3 is fixed by means of screws or the like 
to a conventional hollow section beam 4412 of steel. A groove 412.7 
facilitates fixing such that heads of fastener elements do not protrude. 
FIG. 21 illustrates a modular unit embodying the plate 4412.3 of FIG. 20 
and a plurality of fixed levers 416, carrier elements 414, and the like of 
FIG. 15. This embodiment is virtually identical to the embodiment shown in 
FIG. 15, the only difference being that the beam 412 of FIG. 15 is 
replaced by the conventional beam 4412 and the elongate flat plate 4412.3 
as described with reference to FIG. 20. 
With reference to FIG. 22, an embodiment similar to the embodiment of FIG. 
16 is shown, the only difference being that the beam 512 of FIG. 16 is 
replaced by a conventional beam 5512 in combination with an elongate 
generally flat plate 5512.3 having the mounting formations for the fixed 
levers 516. The flat plate 5512.3 can conveniently be secured to the beam 
5512 by means of headed fasteners, the heads of which are concealed in a 
groove 512.7 in the top of the flat plate 5512.3. 
With reference to FIG. 23, a simplified embodiment comprises an elongate, 
generally flat plate 6612.3 on which a plurality of levers, only one of 
which is shown with reference to its leg 616.3, are welded. The plate 
6612.3 has an elongate groove 612.7 along a top thereof to allow heads of 
screws 612.8 fixing the plate 6612.3 to a timber beam 6612 to be recessed 
and thus not to protrude. 
As mentioned above, the most important advantage of the development of 
FIGS. 17 to 23, is that modular units can be provided for mounting on an 
existing sub-structure or substrate and thus to form a louvre type roof 
construction on the existing sub-structure or substrate.