GB2414251A

GB2414251A - Roof structure

Info

Publication number: GB2414251A
Application number: GB0517938A
Authority: GB
Inventors: David Creighton Mcveigh
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-04-07
Filing date: 2004-04-06
Publication date: 2005-11-23
Anticipated expiration: 2024-04-06
Also published as: GB2400387A; GB0307949D0; GB2400387B; IE20040244A1; GB0517938D0; GB0407877D0; GB2414251B

Abstract

A retractable roof structure for covering a storage space bounded by walls. The structure has a pair of parallel rails 14 mounted on two parallel walls 12. Roof trusses 20 each having a car at each end slide or roll on the rails and a flexible waterproof membrane 22 covers the trusses to provide a continuous, impermeable covering for the roof. The roof trusses and the rails are arranged so that the trusses can all be slid to one end of the rails, to retract the roof, and can be spaced apart along the rails, with the membrane taut between them, when the roof is extended.

Description

241 425 1 - 1 Roof Structure This invention relates to a roof structure

for a building and in particular to a retractable roof structure. The invention is applicable to a storage and comporting silo where organic material is deposited under conditions which allow decomposition of the material (this procedure is also known as an in-vessel composting system).

There is a requirement for storage silos into which bulk material can be brought by lorry, and then enclosed. This requirement is particularly apparent where organic waste material is collected in a silo where it is allowed to decompose to form compost. In this application, the waste material must be kept out of contact with rain and substantially sealed, so that the aerobic decomposition of the organic material can take place as quickly as possible and under optimum conditions.

Depositing of bulk material of this nature requires that heavy transportation equipment carrying the bulk material can enter the silo and then dump the material. Generally the transportation equipment requires considerable headroom to operate and in particular to dump material.

Examples of such transportation equipment are lorries with tipping bodies.

According to the invention, there is provided a retractable roof structure for covering a space defined by walls, the structure comprising a pair of rails to be mounted parallel to one another on two parallel walls, a plurality of roof trusses each having a car at each end - 2 - adapted to slide or roll on the rails and a flexible waterproof membrane spanning between the trusses to provide a continuous, impermeable covering for the roof, the roof trusses and the rails being arranged so that the trusses can all be slid to one end of the rails, to retract the roof, and can be spaced apart along the rails when the roof is extended.

The roof trusses are preferably curved and may be in the form of two curved beams of different radii, braced to one another to produce a rigid truss.

The roof structure can be extended whereupon it covers the space, or retracted whereupon the space is left substantially open from above. An extending and retracting mechanism preferably comprises a rope or cable loop which extends around the periphery of the silo and along the length of each rail between pulleys at each end of the respective rail. The loop is under tension and the cars of the leading edge truss are connected to the cable, so that movement of the cable either pulls the leading car forward, or pulls it back, depending on the direction of rotation of the loop.

The loop can extend around line drivers each operated by a winch handle, so that turning the winch handles in one direction pulls the roof forward to its extended position and turning the handles in the opposite direction pulls the roof back to its retracted position. The cars of the trusses other than the leading truss are entrained, during extension, by the tension in the cover membrane and during retraction, each by contact with the adjacent truss. 3 -

The cable is preferably threaded through eyes on the membrane located between the trusses so that the membrane is gathered up correctly when the roof is being retracted.

The flexible waterproof membrane preferably has skirts which hang down below the cars to overlap the walls bounding the space, to properly enclose the space to avoid entry of vermin and scavengers and to avoid the spread of smell from the decomposing contents of the space.

The rails may be constructed with two parallel tracks, so that two sideby-side spaces can be covered by two adjacent roofs, with a common wall bounding the two spaces.

The rails may form gutters to collect and channel rainwater falling on the roof, and means can be provided to dispose of the rainwater in an appropriate manner.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a first embodiment of a silo in accordance with the invention, with the roof in its extended position; Figure 2 is a rear perspective view showing the silo of Figure 1; Figure 3 is a front perspective view of the silo of - 4 - Figures 1 and 2 with the front open; Figure 4 is a front view of the silo with a front panel in place and showing details of a roof truss; Figure 5 is another front view of the silo, this time showing the roof in place and the front panel removed; Figure 6 is a section through two adjacent silos which share a common wall; Figure 7 is a detail of an arrangement between the end of a roof truss and a rail, from the area within the circle A in Figure 6; Figure 8 is a side view of the first embodiment showing the roof extended; Figure 9 is a view corresponding to Figure 8 but showing the roof retracted; Figure 10 is a schematic plan showing the cabling arrangement; Figure 11 is a side view of a second embodiment showing the roof extended; Figures 12 and 13 are side views of the second embodiment showing two alternative positions for the roof when retracted; and - 5 - Figure 14 shows part of an aeration channel, in exploded view.

Figure 1 shows a silo made up of walls on three sides 10,11,12, with a floor 13 and an open front. The walls are made in sections of concrete A-blocks 5 which are linked together by connecting plates 6 which fit onto threaded studs embedded in the concrete. Nuts are then screwed onto the studs. Blocks of this type are known.

Along the tops of the side walls 10 and 12 are guide rails 14 (which also function as water run-off channels), and these rails extend at 14a beyond the rear ends of the walls 10 and 12, with the ends 14a of the rails being supported on posts 16. Suitable guying or staying measures can be used to support the posts 16.

An arched roof 18 is mounted on the rails 14 and spans between the side walls 10 and 12. In the position shown in Figures 1, 2, 3 and 8 the roof is fully extended over the interior of the silo.

The roof is made up of a number of arcuate roof trusses 20 with a flexible, weatherproof membrane 22 (which may be a pvc coated fabric) stretched between them. The roof can be extended over the whole of the silo (as shown in Figures 1 to 3) or can be retracted to leave the roof of the silo open (Figure 9). When the roof is open, lorries can be driven into the silo and can discharge their loads by tipping the load out. Clearly, it is only possible for lorries to tip their loads in this way if there is ample headroom to allow the vertical movement of the truck body, and the silo described here, with the roof retracted, allows unlimited headroom.

The roof trusses 20 are made up from two steel arcuate sections 24,26 (Figures 3 and 4), of slightly different radius, which are interconnected by webs 28 to impart the necessary rigidity. The ends of the trusses are mounted on wheeled cars or cars 30 which run on the rails 14. In the roof extended condition, the trusses are spaced apart, and the membrane 22 is stretched taut between them, so that a curved roof is formed and rain will run off into the rails 14. In the roof retracted condition (Figure 9) the trusses are slid together and onto the rear extensions 14a of the rails 14. The membrane 22 then concertinas up between the trusses, leaving the roof space above the silo walls completely clear.

When two silos are to be constructed side by side, they may share a common side wall, and Figures 6 and 7 show such an arrangement, with a rail 14 which has cars from one silo running on one flange and cars from the adjacent silo running on the other flange.

Figure 7 shows details of two of the cars 30 and of the rail 14. The rail 14 is a channel section with upwardly directed flanges 15a and 15b. The base of the channel between these flanges provides a rain water gutter, and a skirt 50 provides a continuation of the membrane 22 which extends down into the gutter 14 to direct rainwater into the gutter and actually touches the base of the gutter to assist in enclosing the silo. Each car 30 has a main supporting wheel 17 mounted on the truss 20, for rotation about a horizontal axis. This wheel runs on the upper edge of the flange 15a or 15b.

To prevent the wheel 17 lifting off the rail 14 (which might otherwise tend to happen if wind gets under the roof), the rail 14 has a lateral flange 19, and a bracket 21 extending downwards from the truss 20 has an idler guide wheel 23 which is positioned beneath the flange 19.

The wheel 23 will run on the underside of the lateral flange 19 if the main wheel 17 lifts off the flange 15a.

To keep the main wheel 17 properly positioned on the flange 15a, the bracket 21 also carries a further idler wheel 25 which will run against the edge of the lateral flange 19, if the position of the main wheel 17 moves too far sideways on the flange 15a. Because there will be a similar arrangement at the other end of the truss 20, the wheels 17 on both ends of the truss will be kept in their proper position.

A winding mechanism to extend or retract the roof is fitted around the tops of the walls. The mechanism has a single tensioned cable loop 34 (Figure 10) which is tensioned around pulleys 36, and is attached to the cars 30a at opposite ends of the leading roof truss as indicated at 31. Figure 10 shows only the leading truss, for clarity. The other trusses will run on the rails 14 but will not be connected to the cable 34. Pulling the cable at any point around the loop moves the leading truss forwards or backwards. To pull the cable, it is passed through winding units 37 on the front faces of each wall (Figures 3, 5 and 10). Turning a handle on each of these units pulls one or other run of the cable which then entrains the leading truss. Because there is a single - 8 - cable loop, both ends of the truss will move together. In the embodiment shown in Figure 10 there are winding units 37 at both sides which have to be worked in synchronism to ensure that the truss moves evenly and to introduce the necessary effort into the system to move the heavy masses involved.

One run of the cable 34 is fastened to the leading truss car 30a, so that when the run to which the leading truss car is attached is moving forwards, towards the front of the silo, the leading truss car will follow and the tension in the membrane 22 will cause all the other truss cars to be pulled along behind the front truss until the membrane is taut. A tension strap 48 on the last car Sob will engage behind the back wall 11 of the silo to stop the rearmost truss from being pulled beyond the back wall 11, and a latching mechanism (not shown) can latch the front truss to the front wall, when the roof is fully extended. The detent 48 and this latch will then cause the roof to be locked in its extended position, and the latch or latches will have to be released before the roof can be retracted.

When the roof is to be retracted, the front truss latches will be released and the handles 38 wound in the opposite direction. The leading cars 30a will be pulled backwards until they come into contact with the cars 30 on the adjacent truss which will then be pulled back as a result of their contact with the cars 30a, and this will continue as the handle 38 continues to be wound. The material of the membrane 22 will concertina in between the cars, as can be seen in Figure 9. - 9 -

To avoid the membrane collapsing into the interior of the silo when the roof is being retracted, the membrane has eyes 49 (Figure 8) attached to its inner surface between the cars 30, and one run of the (taut) cable 34 passes through these eyes to hold up the material of the membrane when the membrane itself is no longer stretched taut.

It is important in silos which are to be used for composting organic materials, particularly food waste, that the interior of the silo be sealed to prevent the entry of vermin or the exit of unpleasant smells. The roof shown here has side skirts 50 and an end skirt 52 (see in particular Figure 2) which hang down sufficiently far over the silo walls to prevent the entry of vermin and scavengers. A tight-fitting door will be used to close the front end of the silo.

To fill the silo, lorries carrying waste material reverse into the silo while the roof is retracted and dump their loads. The first load is dumped at the back of the silo, against the rear wall 11, and following loads are dumped progressively nearer the front until the silo is full.

The roof is them extended to cover the whole of the silo and its contents, and the front opening is then closed by a separate front closure panel 100 (Figure 4) which can be brought into place and lowered between two angled channels fitted on the front A-blocks 5. The panel 100 has a vertically mounted tube 102 at the centre, so that a tractor or other implement provided with a vertical spike can insert the spike from below into the tube and lift the panel. To allow the panel 100 to be put in place, a divided front skirt 104 of the membrane 22 is lifted (Figure 5). Each side of the skirt 104 has metal poles inserted into sleeves along the bottom edge, and the ends of these poles can be lifted with suitable straps or hoists to make an open space beneath the roof for access with the door panel.

Figures 1 to 9 show a silo with a fixed back wall 11 and a roof 22 which retracts on the rail extensions 14a, to behind the back wall. It is also possible, as shown in Figures 11, 12 and 13, to arrange the roof so that it can be retracted either to the rear (Figure 12) or to the front (Figure 13). With this arrangement, the silo can be filled from the front and emptied from the back. This avoids any possible cross-contamination (for example carried by Lyres) between vehicles bringing untreated material with vehicles removing treated material.

In this embodiment, it may not be possible to have a single, continuous cable loop attached to both ends of the leading truss and extending across the silo, so two separate loops 134, one on each rail 14, can be provided.

These can be operated from either end of the silo, through winding units 138a or 138b.

In a silo of this type, a door panel 100 will be required at each end, and separate winding mechanisms will be needed on each side wall.

Once the front panel(s) is(are) in place, aerobic digestion of the silo contents can begin, by drawing air from the space below the roof and above the silo contents - 11 and blowing the air back into the bottom of the silo contents through aeration channels 54. This recycling of the air is important to build up the necessary temperature conditions in the decomposing material.

The aeration channels are shown in Figure 14. They are designed to be mounted on the floor of the silo, to extend the full length of the silo and to be mounted about two metres apart across the silo floor. The channels have to be strong enough not to distort when a fully laden lorry is driven over them, and need to be easy to clean, as the decomposing material may otherwise block the channels.

The channels have a base channel 56 and a cover channel 58. The base channel is permanently mounted on the silo floor and has air outlets 60 through its side walls, spaced apart along its length. The cover channel 58 is open at its underneath face, so that it can drop over the base channel. The base channel has internal lugs 62 which can receive an internal bar 64 mounted inside the cover channel so that when the cover channel is fitted over the base channel and slid longitudinally, the bar 64 engages under the lugs 62 to hold the two parts together, while allowing them to be separated when necessary by reversing the longitudinal movement. The lateral dimensions of the two channels are such that the cover fits snugly over the base, but when air is blown into and long the base channel, it can escape through the outlets 60 and through a gap between the side walls of the overlapping channels.

The front end 66 of the cover channel 58 is sloped so that it does not present a serious obstruction to vehicle - 12 movement over the silo floor.

The silo described here is especially adapted to be used in the handling and decomposition of organic wastes.

However the invention is not limited to such an application, and a retractable roof as described here can be used in many different applications. - 13

Claims

Claims 1. A retractable roof structure for covering a space defined by

walls, the structure comprising a pair of rails to be mounted parallel to one another on two parallel walls, a plurality of roof trusses each having a car at each end adapted to slide or roll on the rails and a flexible waterproof membrane spanning between the trusses to provide a continuous, impermeable covering for the roof, the roof trusses and the rails being arranged so that the trusses can all be slid to one end of the rails, to retract the roof, and can be spaced apart along the rails when the roof is extended.
2. A roof structure as claimed in Claim 1, wherein the rails extend beyond one end of the space, and means are provided for supporting the ends of the rails which extend beyond the space.
3. A roof structure as claimed in Claim 1, wherein the trusses can be slid to either end of the roof.
4. A roof structure as claimed in any preceding claim, wherein the roof trusses are curved.
5. A roof structure as claimed in Claim 3, wherein the roof trusses are in the form of two curved beams of different radii, braced to one another to produce a rigid truss.
6. A roof structure as claimed in any preceding claim, wherein the roof can be extended and retracted by means of - 14 an extending and retracting mechanism comprising rope or cable loops which extend along the length of each rail, are under tension and have the cars of the leading edge truss connected to the cable, so that movement of the cable either pulls the leading car forward, or pulls it back, depending on the direction of rotation of the loop.
7. A roof structure as claimed in Claim 6, wherein a single cable loop extends around the structure and along both parallel walls and is connected to both ends of the leading car so that both ends of the leading car are constrained to move in parallel.
8. A roof structure as claimed in any preceding claim, wherein the cars of the trusses other than the leading truss are entrained, during extension, by the tension in the cover membrane and during retraction, each by contact with the adjacent truss.
9. A roof structure as claimed in any preceding claim, wherein the flexible waterproof membrane has skirts which hang down below the cars to overlap the walls bounding the space, to enclose the space.
10. A roof structure as claimed in any preceding claim, wherein the rails are constructed with two parallel tracks, so that two side-by-side spaces can be covered by two adjacent roofs, with a common wall bounding the two spaces.
11. A roof structure as claimed in any preceding claim, wherein the rails form gutters to collect and channel away - 15 rainwater falling on the roof.
12. A retractable roof structure substantially as herein described with reference to any one embodiment shown in the accompanying drawings.