FIELD OF THE INVENTION

This invention relates to roofed structures and has particular application to a structure having a roof comprising one or more panels of plastics film or similar material.

Although the structure used as an example in this specification is a green house, the invention can be applied to a wide range of other roofed structures including stock shelters, implement storage sheds and in fact dry storage areas for virtually any suitable purpose.

BACKGROUND OF THE INVENTION

Structures comprising roof panels of plastics film are now in widespread use owing to their low cost and the speed at which they can be erected. They commonly comprise at least two spaced parallel beams supported by poles fixed in the ground. Cross members, which for convenience will be referred to as rafters, span the beams and support the roof panels. The rafters may take the form of arches of curved or pitched shape or they may simply be straight.

Plastics film or the like is also commonly used for wall panels and internal screening of structures such as tunnel houses.

It is necessary to pull the panel tight and anchor it firmly in place so that it is as immobile as possible in use. This is to prevent the panel from flapping in the wind and also to prevent sagging and thus allowing rain water to collect thereon. For the same reason there should be as little wrinkling in the panel as possible.

It is known to fix the panels on the beams and rafters by means of elongate clips which clip over complementally shaped elongate ribs mounted on or formed integrally with the beams and rafters, the film being clamped between the clips and the ribs. An example of such an arrangement is disclosed in New Zealand patent application #203881. It is convenient that the rib should be incorporated in an aluminium (or plastics) extrusion which constitutes or is attached to a beam or rafter. It is also known to use a clip to clamp the film in a longitudinally extending channel formed in the beam. Such an arrangement is disclosed in US patent #4452230.

The majority of tunnel hoses including those disclosed in the above

entioned patents are used for horticultural purposes and in such applications it is likely that moisture will condense on the inner face of the film. It is often necessary to prevent condensate from dripping onto plants therebelow. For this purpose some commercially available systems are provided with gutters which are located below points on the roof panels from which condensate is apt to drop. In one known system, a trough shaped member serves to support the panels. The trough carries rain water off. A separate gutter element is mounted above the poles and immediately below the lowest point of the trough. An: condensate which forms runs down to the lowest point of the trough and drips into the gutter.

A common method of fixing rafters to the beams is to provide a member which is fixed to the beam by nailing, bolting, rivetting or welding (depending on the nature of the beam) and which incorporates a socket in which the end of the rafter is fixed. Cross struts for strengthening arch shaped rafters are fixed to the beams in a similar way.

It is a disadvantage of all of the commercially available systems known to the applicant t_.__t a substantial amount of on-site fitting including cutting and drilling is required. This is due to the fact that the final position of most of the components is determined only after the poles and the beams are erected and that these components are in most cases fixed in place by means of nails, screws, bolts or the like.

SUMMARY OF THE INVENTION

According to the invention there is provided a building system including a structure comprising an elongate structural element and spaced apart support members for supporting at least two roof panels of laminar material located one on either side of the element, characterised in that the element comprises paired longitudinally extending formations including a first pair of said formations which interact with clamping members for clamping the panels on the element and a second pair of said formations which interact with mountings for mounting the support members on the element, the formations in the second pair being located below the formations in the first pair and being such that the mountings can slide along the element while being held captive thereon.

In one form of the invention the element comprises an upper wall having longitudinally extending edges adjacent which said formations in the first pair are located.

According to one aspect of the invention the element comprises spaced side walls, said formations in the first pair projecting outwardly from the side walls in opposite directions.

According to a further aspect of the invention the element comprises a lower wall located below the upper wall, and the side walls intersect the upper and lower walls to form a closed box section.

In one form of the invention said formations in the first pair define upwardly opening channels and the clamping members are clipped into the channels.

Advantageously said formations in the second pair define channels which open outwardly in opposite directions and in which the mountings are held captive.

According to yet another aspect of the invention said formations include a third pair which are located below said formations in the second pair, said formations in the third pair interacting with devices for joining the element to ground supports on which the element is supported, said devices being such that they can slide along the element while being held captive thereon.

The ground support will usually but not essentially take the form of a pole or similar column fixed in the ground. In this case, said devices are advantageously provided each with a socket or recess for receiving the pole. For a hollow pole, said device may be provided with a spigot which is inserted in the pole instead of a socket.

Advantageously said formations in the third pair define channels which open outwardly in opposite directions.

According to still another aspect of the invention a longitudinally extending gutter member is clipped into at least one of the channels defined by said formations in the third pair, the gutter member projecting outwardly from the element sufficiently to catch water which drops from a said formation in the first pair above the gutter member. The gutter member may serve to clamp an additional panel on the beam.

The gutter member may be positioned inside the structure and adapted to collect condensate which forms inside the structure and collects at the beam. Alternatively the gutter member may be positioned on a beam located at the base of the roof and adapted to collect rain water which runs down the roof.

Advantageously the channels defined by said formations in the first pair and in the third pair are of substantially similar cross sectional profile. This enables another panel (for example a side panel or a shade panel) to be clamped on the beam by using the same clamping member as is used for the roof panels.

It is an important advantage of the invention that the beam and the gutters can be formed from extrusions and furthermore that the members for joining the rafters, poles and other transverse members such as stiffening struts to the beam can be formed by cutting extrusions into short lengths.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention are further discussed with reference to the accompanying drawings in which:

Figure 1 is a cross sectional view of a beam forming part of a tunnel house, various components for attaching flexible laminar panels to the beam being mounted thereon; Figure 2 is a cross sectional view of the beam illustrated in Figure 1 showing a component for attaching the beam to a pole; Figure 3 is a cross sectional view of the beam illustrated in Figure 1 showing a component for attaching the beam to a cross strut; Figure 4 is a somewhat schematic small scale view of part of a tunnel house, showing the components illustrated in Figures 1 to 3; Figure 5 is a view, similar to Figure 1, showing a modified beam with a rain gutter attached thereto;

Figure 6 is a sectional plan view at the end of a beam with a cross beam joined thereto; Figure 7 is a fragmentary view on arrow A in Figure 1, showing a rafter mounting component; and Figure 8 is a view of a pin by means of which the rafter mounting component is locked in position on the beam.

DESCRIPTION OF THE EMBODIMENTS SHOWN IN THE DRAWINGS

All of the views, except Figure 4, are full size and substantially to scale.

In Figures 1 to 4 the extrusion 10 is intended for use as a beam for supporting the roof of a tunnel house T and will therefore be referred to as such. The beam is of rectangular box section comprising two side

walls 12, 12', an upper wall 14 and a lower wall 16. The beam is symmetrical about a central vertical plane and only the wall 12 will therefore be described.

Important features of the side wall 12 comprise three protuberances 18, 20 and 22 each of which extends the full length of the beam, being formed integrally therewith as part of the extrusion. The protuberances 18, 20 project at the same height above the outer face 24 of the side wall and have lips 26, 28 at their outer ends which project towards each other. A first longitudinally extending channel 30 is thus defined between the protuberances 18, 20.

The height of the third protuberance 22 above the outer face of the side wall is somewhat greater than that of the protuberances 18, 20. At its outer edge the protuberance 22 curls back on itself to form a lip 32 projecting towards the upper wall 14 of the beam. A small lip 34 projecting towards the lip 32 is formed in the side wall 12 at its junction with the upper wall 14. A second longitudinally extending channel 36 is thus defined by the protuberance 22 and the lips 32, 34. The shape and dimensions of the channel 36 are substantially similar to those of the channel 30. The reason for this will be explained.

A third longitudinally extending channel formation 38 is defined by lips 40, 42 formed respectively in the upper face of protuberance 20 and the lower face of the protuberance 22.

The beam is mounted on spaced posts (indicated in dotted outline at 44 in Figure 2) by means of joints 46. The joints are formed from an aluminium extrusion cut into short lengths. In cross section this extrusion comprises a base 48 from which depend two spaced parallel side walls 50, 50'; and two spaced longitudinally extending flanges 52, 52' rising from the base. Each flange 52, 52' has a returned portion formed in its outer edge constituting a hook formation 54. Each joint is shaped so that the hook formations can engage the lips 26, 26' when the joint is offered up the the end of the beam. The joint can slide along the beam but is otherwise fixed thereon. When the beam is located in its correct position on the posts (as will be described) the joints can be fixed to the posts by means of pins (not shown) passed through holes predrilled in the side walls 50, 50' and the upper ends of the posts. Spring loaded clips or any other suitable type of fastening may be used instead of pins. The spring loaded pin may be of the type described below with reference to Figure 3.

As shown in Figure 3, the extrusion used to make the joints 46 can also

be used to make mounts 47 for cross struts 110 or other components which span the beams. Incidentally the extrusion shown in Figure 3 from which the mounts are cut comprises minor modifications which have been incorporated for the purpose of producing a cheaper extrusion. Each cross strut comprises a pipe which is swaged at one end 112 as shown at 114 and inserted through a hole 116 in the wall 50 of the mount 47. This swaged end 114 is pushed into the unswaged opposite end 118 of the pipe for a second cross strut. The swaged end is a close fit in the hole 116 so that the shoulder of the swaged portion abuts the outer face 120 of the wall 50. The end 118 of the second strut projects through a hole 122 in the wall 50' and abuts the inner face 124 of the wall 50. The two struts are locked together by means of a spring loaded peg 126 which projects through holes 128 in the walls of the struts which are in register when the struts are correctly positioned.

The mounts 47 can be used to mount other structural components which span the beams. Examples of such components include irrigation pipes and rails for supporting a travelling irrigation system. The means for mounting these components on the mounts are modified to suit the application.

Arch shaped rafters 56 can be mounted on the beam by means of mountings 58. The mountings are formed by cutting an aluminium extrusion into short lengths. This extrusion comprises a base 60 from which arise upper and lower side walls and an interior wall 62 joining the side walls. The upper side wall comprises a portion 64 adjacent the base and perpendicular thereto; and a downwardly angled portion 66 parallel to the interior wall 62. The lower side wall comprises a portion 68 adjacent the base and a second portion 70 which joins the portion 66 of the upper side wall. The portions 68 and 70 are upwardly angled and mutually parallel but are spaced from one another by means of a joining portion 72 disposed parallel to the downwardly angled portion 66 of the lower side wall. The lower edge of the base comprises a lip which engages the lip 40' in the protuberance 18' of the beam. Similarly the upper edge of the base comprises a lip which engages the lip 42' in the protuberance 22' . The mounting 58 can thus be offered up to the end of the beam and can slide along the channel 38' but is otherwise locked on the beam. When the mounting 58 has been slid to its correct position on the beam the rafter can be inserted in a socket predrilled in the portion 66 of the upper wall and the interior wall 60. The joining portion 72 serves as a base of the socket to support the end of the rafter.

The beams and rafters support panels P of plastics film as shown more

particularly in Figure 5. The panels are fixed to the beam by means of elongate clips 74 which are clipped into the channels 36, 36'. In cross section a clip comprises spaced side walls 76, 78 joined by a base 80. The side walls converge from the base towards their free edges. The outer side wall 78 is provided with a longitudinally extending outwardly projecting rib 82 which engages the lip 32, 32' of the channel 36, 36'. The inner side wall 76 is thinner than the side wall 78 and can be sprung inwardly to allow a longitudinally extending dimple 84 formed therein to engage the lip 34.

Because of the angle at which the panel rises from the beam and the position at which it joins the beam, condensate will run down the inner face of the panel and drop off the outer edge of the protuberance 22' . This condensate can be caught by means of a gutter 90 clipped into the channel 30'. The gutter is yet another aluminium extrusion comprising a channel portion 92 including an inner wall 94 provided with upper and lower flanges 96, 98. The upper flange has a rib 100 which is substantially identical to the rib 82 of the clip 74. Similarly the lower flange has a dimple 102 which is substantially identical to the dimple 84 in the clip. After engaging the rib 100 behind the lip 28, the flanges can be sprung inwardly to allow the dimple 102 to engage the lip 26'. Where the gutter encounters a joint 46, a short length of the lower flange 98 can be cut away. This is done in the workshop.

It is an advantage of the construction that neither the joints 46, 47, the mounts 56 nor the gutters need be fixed in place by extraneous fastenings such as rivets, bolts, nails or screws. Erection is therefore very fast. After the posts are fixed in place, the lengths of extrusion making up the beams are laid on the ground next to the poles on which they will be erected. Joints 46 are slid onto each beam, one for each pole. Similarly, the mounts 46, 47 are slid onto each beam. The beams are then joined together by means of joining pieces 104 (also cut from an aluminium extrusion) inserted in the ends of each beam. In the present example, the joining pieces are a press fit in the beams which are thus held together by friction only. A joint between two beams is shown in cross section in Figure 8. After the beams are joined together the gutters may be mounted. It is an advantage of the invention that the cutouts in the lower flanges of the gutter sections for accommodating the joints serves to locate the joints in their correct positions before the made up beams are lifted into place.

The rafters are mounted after the made up beams are placed on the poles. The rafters can be mounted either before or after the roof panels are erected.

The reason for the similar geometry of the profiles of the channels 30, 30' and 36, 36' is that a clip 74 can be used to clamp a side panel or an interior panel (indicated at P') such as a shade cloth in a channel 30, 30'. It is not necessary for the cahnnel profiles to be absolutely identical for this purpose.

The component 130 shown in Figure 3 is another extrusion which can be clipped to the beam. It functions as an external gutter for catching rain water when the beam 10 shown is located at the top of an outer wall of the tunnel house. This gutter is also able to clamp a wall panel to the channel 30, 30' in which the gutter is mounted.

Another gutter is shown in Figure 5. This comprises a trough shaped extrusion 140 which extends along the beam and engages, as by now will be clear, in the channel 30 of the beam. The extrusion 140 is supported by hooks 142. These hooks are formed by an extrusion cut into short lengths and located at intervals along the beam. As will also be clear each hook engages the channel 36 and the lip 42 of the beam. The hook has an outwardly projecting flange 144 which, at its outer end has an upstanding rib 146 which clips into a longitudinally extending recess in the vertical wall 148 of the gutter. The gutter can thus be clipped in place. It can also be used to clamp a side panel P' in the channel 30 of the beam.

Incidentally the extrusions shown in Figure 5 are modified. In particular the beam 10' is wider than the beam 10 and dimples 200 are formed in the floors of the channels 36, 36'. These dimples help to prevent the clips 74 from becoming accidentally disengaged.

The side walls of the clip 74 shown in Figure 5 are slightly higher than those of the clip 74. The clip 74' has a greater degree of spring than the clip 74.

Referring to Figure 8, a cross beam 10a is joined to the end of a beam 10b. The profile of the beams 10a, 10b are the same as the beam 10'. The beams are joined by means of a joint 300 also formed from an extrusion. The joint 300 comprises a base 302 from which arise side walls 304. The base 302 is a sliding fit in the channel 38, 38' of the beam 10a. The side walls 304 are a push fit in the channels 38, 38' of the beam 10b. It is necessary to cut the side walls away at their edges where they join the base so that the joint can accomodate the lips 40, 42 (or 40', 42') of the cross beam 10a. Again this connection can be made without fastenings such as screws or the like.

Figure 8 also shows two beams joined end to end above a pole 44.

In the present examples the extrusions are of aluminium although this is not essential. Extrusions of plastics material could be used. The clearances and tolerances between the components, particularly between the clips 74 and the channels 36, 36' can be held such that the joints between the roof panels P and the beams are watertight. Rain water will thus run along the tops of the upper walls 14 of the beams. It may be necessary to apply a sealing compound to the joining members 104 and the end faces of the beams before they are joined together.

It will be noted that a narrow space 202 is left at the interface between the beam and the joint 58. Referring particularly to Figures 6 and 7 a clip 204, preferably of stainless steel, comprises a shank 206 in which two cam like indentations 208 are formed. The clip is curved around at one end of the shank to form a head 210 by means of which the clip can be grasped and manipulated. The shank is inserted in the space 202 and the head is then twisted around (against the spring of the metal) and hooked behind the wall 68 of the joint 58. This provides sufficient friction to lock the joint in place.

Similar spaces are left between the beam and the other components mounted thereon. The same or similar clips 204 can be used to lock these components in place.

The arrangement of the beam results in a number of further advantages. The location of the channels 36, 36' above and outside the channels 38, 38' reduces the possibility of the panels P catching on the joints 58 (or other parts of the beam) or rafters during erection and being torn. The beams are wide enough to provide a foothold for a workman during erection. At the same time they do not substantially impede light penetration to the interior of the tunnel house. Because of the height of the clips 74, 74' the tops thereof are well spaced from the panels and the risk of the panels being damaged by a workman's boot or other footwear is reduced. The beams are also strong enough to span up to about 4 metres and support the weight of a workman. At the same time the amount of metal in the beams is optimised so that they are very economical. If the panels are rigid, they can be attached to the beams by means of clips similar to the clips 74, 74' but capable of being attached to the panels prior to erection.