AU603170B2 - Improvements in decking or roofing sheets - Google Patents

Description

COMMONWEALTH OF AUSTRALIA Patents Act 1952 Name of Applicant Address of Applicant Actual Inventor Address f or Service COMPLETE SPECIFI CAT] THE ROOFING CENTRE PTY LTD 201 Jackson Road, SUNNYBANK HILLS QLD AUSTRALI A 4109 Graeme Neville KING GRANT ADAMS COMPANY Patent Trade Mark Attorneys Level 9 NATIONAL MUTUAL CENTRE 144 Edward Street BRISBANE QUEENSLAND 4000 AUSTRALI A ON FOR THE INVENTION ENTITLED: IMPROVEMENTS IN DECKING OR ROOFING SHEETS The following statement is a full description of the invention including the best method of performing it known to the applicant.

rc i1 THIS INVENTION relates to improvements in decking or roofing sheets.

A well-known and widely used kind of decking or roofing sheet is roll-formed of sheet metal to a profile having high load-bearing ribs at its sides and at one or more intermediate positions, the spaces between the ribs, or pans, being formed with a series of low stiffening beads parallel to the high ribs. The high ribs include overlap and underlap ribs at opposite sides of the sheet, the overlap rib being profiled to snap down into firm engagement with the underlap rib at the opposite side of a similar adjacent sheet and in such manner as to prevent passage of water between the two.

Adjacent similar sheets may be secretly fixed by the use of concealed fixing brackets which are nailed or otherwise fixed to purlins, each of these brackets having, at opposite sides, upwardly extending fixing spurs with which a side and an intermediate rib may be snapped into engagement, projections of the spurs becoming engaged in longitudinal recesses formed in the sides of the ribs.

Although decking sheets of this type are Sgenerally very satisfactory, they have the disadvantage that, in conditions where high velocity winds pass over a low-pitch roof of these sheets, a pressure differential brought about between the top and bottom of the roof is likely to cause the pans of the sheets to bow upwardly. This lift and deformation of the sheets may be sufficient to cause the sides of the high ribs to be forced apart to such extent that the ribs become disengaged from the fixing spurs of the brackets so that the sheets may be blown from the building. i The decking sheets, instead of being secretfixed, may be pierce-fixed, fasteners being screwed -2through either the pans or the ribs into the purlins below. Although this manner of fixing obviates or greatly reduces the problems of wind-uplift, there remains difficulties caused by live construction loads applied by workmen who must stand or kneel on the sheets and move from one support to the next in the course of fixing the sheets. Building codes specify the maximum distance that a deck can span between roof supports, this distance being determined as the span capable of withstanding, without any visible damage, live construction loads which are mechanicaly simulated in testing.

The present invention has been devised with 04*a o, 0 the general object of providing a decking or roofing sheet of the general character set out which is capable o of withstanding very considerable stresses on the pans, whether imposed by high wind conditions or by live construction loading.

With the foregoing and other objects in view, 9° 20 the invention resides broadly in a decking sheet of the type having a plurality of upstanding longitudinal load-bearing ribs including overlapping and underlapping d ribs at its sides and, between each pair of succeeding ribs, a substantially flat section or pan formed with S 25 relatively shallow stiffening beads; wherein the stiffening beads are at an angle between 450 and 6 0 P-z 1"O to the said ribs. The stiffening beads preferably terminate short of the high ribs at the sides of the pan to allow free waterways along the pans. Other features of the invention will become apparent from the following description.

In order that a preferred embodiment of the invention may be readily understood and carried into practical effect, reference is now made to the accompanying drawings, wherein:- -3- FIG. 1 is a perspective view of a decking sheet according to the invention, and FIG. 2 is a cross-sectional view of secretfixed decking sheets according to the invention.

As shown in FIG. 2, a roof or deck has a series of concealed fixing brackets 10 nailed or otherwise secured in spaced arrangement to each of the purlins 11 of the structure. Each of the brackets terminates at its ends in upstanding fixing spurs 12 and 13 with which roofing sheets 14 are quickly and simply engaged.

Each of the roofing sheets 14 is formed in usual manner with a series of parallel longitudinal high load-bearing ribs, these comprising, in the embodiment illustrated, an overlap rib 15 at one side of the sheet, an underlap rib 16 at the other side of the sheet, and a single intermediate rib 17 extending down the middle {j of the sheet.

I Each of a series of fixing brackets 10 is fixed to a purlin 11 with its spur 12 hooked over the underlap rib 16 of one sheet 14 already laid, and the next sheet 14 has its overlap rib 15 snapped down over this underlap rib 16 and has its intermediate rib 17 snapped down into engagement with the spur 13 of the fixing bracket, and so on.

Each overlap rib 15 is profiled for engagement with projections or teeth 18 of the spurs 1 of V the series of fixing brackets 10, and each intermediate rib 17 is shaped for engagement with pairs of oppositely extending projections or teeth 18 from the spurs 13 of the brackets.

The salient feature of the invention is the formation, in each of the relatively flat sections or pans 19 of the sheet 14, between the overlap rib 15 and the intermediate rib 17, and between the underlap rib 16 -4iz. 1C r and the intermediate rib, of a series of stiffening beads "0 which, instead of being parallel to the high load bearing ribs 15, 16 and 17 are oblique, and at an angle of about 45 to 600 to the ribs. The stiffening beads 20 of the two pans of the sheet 14 illustrated are in equally spaced arrangement, those of one pan inclining in opposite direction to those of the other pan. The beads 20 of each series terminate some distance short of the high ribs at the sides of the pan.

The stiffening beads 20 may be pressed in the sheet, or they may be roll-formed between a male roller made with helical teeth and a female roller which is of yieldable material such as rubber, or is formed with helical grooves with which the helical teeth of the male roller coact.

It will be found that the oblique stiffening bezc\d 4 .L 20 effectively resist upwards bowing of the pans 19 even during strong wind conditions, and so the likelihood of the high ribs 15, 16 and 17 being so deformed as to disengage from the spur projections 18 and 19 of the fixing brackets 10 is obviated or greatly reduced.

As the stiffening beads 20 are not carried completely to the high ribs 15, 16 and 17, water can flow freely down a pitched roof.

Roofing or decking sheets as described and illustrated may, if preferred, be pierce-fixed to the purlins 11. In this manner of fixing, the concealed fixing brackets 10 are omitted, and fasteners are screwed through either the parts 19 or the ribs 15, 16, 17 into the purlins 11 below. The roofing sheets according to the invention will be found to be highly resistant to damage from live construction loads. The distance between purlins spanned by the sheets may therefore be greater than is the case with conventional decking sheets and so, by the reduction in the number Q2 1J~i~\ &NT -i II-CI UI of purlins, economies of construction may be achieved.

Although decking of roofing sheets as described and illustrated will be found to be very effective in achieving the objects for which they have been devised, it will of course be understood that many modifications of constructional detail and design may be made within the ambit of the invention hereinafter claimed.

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Claims (4)

1. A decking sheet of the type having a plurality of upstanding longitudinal load-bearing ribs including overlapping and underlapping ribs at its sides and, between each pair of succeeding ribs, a substantially flat section or pan formed with relatively shallow stiffening beads, wherein: the stiffe ling beads are at an angle between and 60° to the said ribs.

2. A decking sheet according to Claim 1 wherein: the stiffening beads of each pan are in equally spaced parallel relationship.

3. A decking sheet according to Claim 1 or Claim 2 wherein: the stiffening beads terminate some distance short of the ribs to both sides of the pan.

4. A decking sheet substantially as herein described with reference to the accompanying drawings. DATED this nineteenth day of March 1990. THE ROOFING CENTRE PTY LTD by their Patent Attorneys GRANT ADAMS COMPANY 7 'II \sjI