Patent Publication Number: US-2010126107-A1

Title: Roofing tile clip and installation method

Description:
FIELD OF THE INVENTION 
     The present invention relates to roofing tile clips, and in particular, to roofing tile clips for tile roofs constructed in cyclone prone areas. 
     BACKGROUND ART 
     In one form a conventional tiled roof, the roof is supported by rafters which run down the slope of the roof from a ridge line to an eave. Running substantially horizontally across the rafters are a plurality of lightweight timber bearers called battens which are spaced apart at a distance which approximately corresponds to the length of each tile. The battens can be fabricated from either softwood or hardwood. The tiles are placed on the battens with a higher part of each tile underlying a lower part of an adjacent tile. Such tiles are typically terracotta or concrete and are relatively heavy. Thus in those areas where high winds are not to be anticipated, the tiles are either maintained in position by their own weight, or tied to the batten by small gauge soft wire. However, in those areas subject to cyclones (or hurricanes or typhoons as the storms are known in the northern hemisphere) batten clips are used to secure the tiles to the battens and so enable the tiles to resist updrafts created by cyclonic storms which would otherwise dislodge the tiles. 
     In another type of conventional typed roof the rafters are covered by a sheet layer such as plywood which forms a deck. This is then covered with a waterproof membrane or layer of some kind Tiles are then laid on the deck either with or without battens being laid. Battens are laid as above mainly on steeper rooves having a deck. Such tiles are held in place against high winds by means of a metal deck clip. 
     Australian Patent Specification No. 76700/74 (which substantially corresponds to U.S. Pat. No. 4,182,090) and Australian Design Registration No. 65856 disclose one form of prior art batten clip. Such clips have hitherto been fabricated from galvanised sheet steel and suffer from a number of inherent disadvantages to be described hereafter in more detail. 
     The genesis of the present invention is a desire to provide an alternative clip, and a method of installing same, which at least ameliorates some of the above mentioned disadvantages. 
     SUMMARY OF INVENTION 
     In accordance with a first aspect of the present invention there is disclosed a roofing tile clip fabricated in two parts, one of said parts comprising an elongated strip having a plurality of teeth extending from one side thereof and terminating in a hook shaped to engage with the side edge of a substantially planar roofing tile, the other of said parts comprising a generally tubular body having a longitudinal axis and an opening therethrough substantially aligned with said axis and shaped to receive said strip, said tubular body having a ratchet mechanism arranged to co-operate with said teeth and permit movement of said hook towards, but not away from, said tubular body, and said other part including an elongate base which extends generally at right angles to said longitudinal axis, said base including at least one bore therethrough shaped to received a fastener for said clip, and said base having an abutment surface substantially perpendicular to said bore which, after installation, bears against a support surface, and through which said fastener can extend. 
     In accordance with a second aspect of the present invention there is disclosed a method of installing on a sloping first tile of a roof, a roofing clip as described above, said method comprising the steps of: 
     (i) bringing said abutment surface of said base into contact with said support surface, 
     (ii) driving a fastener through said base and into said support surface to secure said other part thereto, and 
     (iii) after carrying out steps (i) and (ii) bringing said hook into contact with said tile whilst simultaneously passing at least some of said teeth through said ratchet mechanism. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Two embodiments of the present invention will now be described with reference to the drawings in which: 
         FIG. 1  is a perspective view of the prior art batten clip installed; 
         FIG. 2  is an enlarged view of  FIG. 1  without the tiles being illustrated and showing the detail of the construction of the clip; 
         FIG. 3  is a front perspective view of a prior art deck clip; 
         FIG. 4  is a front perspective view of the lower portion of a two part clip of a first embodiment; 
         FIG. 5  is a rear perspective view of the upper portion of the two part clip of the first embodiment; 
         FIG. 6  is a front perspective view of the assembled clip of the first embodiment; 
         FIG. 7  is a perspective view similar to  FIG. 1  and showing the batten clip of the first embodiment installed and being set; 
         FIG. 8  is a perspective view from above of an assembled two part deck clip of a second embodiment; 
         FIG. 9  is a perspective view from below of the clip of  FIG. 8 ; 
         FIG. 10  is a plan view of the clip of  FIG. 8 ; 
         FIG. 11  is a left side elevation of the clip of  FIG. 8 ; 
         FIG. 12  is an inverted plan view of the clip of  FIG. 8 ; 
         FIG. 13  is a front view of the clip of  FIG. 8 ; 
         FIG. 14  is a right side elevation of the clip of  FIG. 8 ; 
         FIG. 15  is a rear view of the clip of  FIG. 8 ; and 
         FIG. 16  is a cut-away perspective view of a roof deck showing the clip of  FIGS. 8-15  installed and in a battenless arrangement. 
     
    
    
     DETAILED DESCRIPTION 
     As seen in  FIG. 1 , two tiles  1 ,  2  are arranged in adjacent courses with the tile  1  being in a course above the tile  2  so that water is shed from tile  1  onto tile  2 . A higher part  11  of tile  1  overlies a lower part  22  of tile  2  to provide the desired overlap of the tiles. Only the batten  3  supporting tile  2  is illustrated in  FIG. 1 . A nail  4  which passes through the lower end  6  of a prior art metal batten clip  5  is partially driven into the batten  3 . The upper end  7  of the clip  5  is formed into a hook which engages with the tile  1 . This is the clip disclosed in U.S. Pat. No. 4,182,090 (Aarons). 
     As seen in  FIG. 2 , the clip  5  is fabricated from galvanised sheet steel, such as that sold under the trade name GALVABOND with the clip  5  being formed by pressing or cutting from a large galvanised sheet. Accordingly, the edges  15  of the clip  5  are not galvanised but are unprotected steel. Preferably the hook  7  and upper portion of the clip  5  are provided with a pressed stiffening rib  17 . At the lower end  6  a loop  16  is formed by shearing a medial strip so as to form an eye shaped opening  19  through which the shank  24  of the nail  4  can pass. It will be appreciated from  FIG. 2  that the edges  26  of the loop  16  which are formed during the shearing of the clip  5  are also constituted by unprotected steel. 
     It will also be apparent from  FIGS. 1 and 2 , that the clip  5  is essentially in contact with the tile  2  which overhangs the batten  3  and thus the edge of the clip  5  is spaced from the batten  3  a distance X indicated in  FIG. 2 . 
     The abovementioned arrangement suffers from several disadvantages. Firstly, it is prohibitively expensive to manufacture the clip  5  from a rust resistant material such as stainless steel, and thus galvanised sheet steel must be used. However, the edges  15  and  26  of the clip  5  are prone to rusting which is a particular problem in cyclone prone areas since these are located in the tropics and near tropical seas. 
     Secondly, ideally the nail  4  should be galvanised in order to protect the nail  4  from rust. However, the sharp edges  26  of the loop  16  in practice strip any galvanising material on the shank  24  of the nail  4 . As a consequence, it is the practice not to use the expensive galvanised nails but to instead use normal mild steel nails since a galvanised nail with the galvanising partly stripped away offers no practical protection. 
     Thirdly, the nail  4  is only partially driven into the batten  3  and this requires the exercise of some skill and judgement on behalf of the installer. In particular, if the nail  4  is not driven a sufficient distance into the batten  3 , the nail  4  will not adequately secure the clip  5  to the batten  3 . Conversely, if the nail  4  is driven too far into the batten  3 , the head  4  can distort the lower end  6  of the clip  5 , thereby damaging the clip and lessening its holding ability. 
     The tiler or roofer does not know exactly how hard to drive in the nail because the nail is never driven fully home. If the nail is driven in too far, of the clip will be bent, thereby distorting the entire device and resulting in the hook  7  being dislodged from the tile. Alternatively, if the nail is not driven in far enough, the head of the nail does not abut the clip  5 . In this position, if the wind should lift the tile  1 , the hook  7  will tend to move towards the tile  2  and the loop  16  will tend to slide towards the head  34  of the nail  4 . As a consequence, an increased bending moment is applied to the nail, which then results in the shank  24  of the nail  4  bending upwardly. As a consequence of this bending, the original tension in the clip  5  caused by the placement of the nail  4  is lost and the hook  7  will work loose from the tile  1 . 
     As seen in  FIG. 3  a prior art mental deck clip  50  is illustrated. The clip  50  is also formed from strip sheet metal and has a hook  57 , a body  55  and a foot  56 . The foot  56  includes two apertures  54  intended to each receive a corresponding nail. The floor  56  lies flat on the deck  51  which although sloping, does not slope at an angle equal to the slope of the tile  1 . This is because the tile  1  overlies the tile  2 . As a consequence of this geometric arrangement the contact between the hook  57  and the tile  1  is an edge contact—not a broad surface contact. In particular, as seen in  FIG. 3  it is the right hand edge of the hook  57  which comes into contact with the tile  1 . This edge contact applies large forces to the edge of the hook  57  and can result in plastic (and therefore permanent) deformation of the hook  57 . 
     Furthermore, the clip  50  has a fixed hook height. As a consequence each different type of tile requires a corresponding special clip so that a large inventory of different clips  50  must be maintained to suit each corresponding different tile type. Also somewhat paradoxically, new tile designs are designed to use one of the existing ranges of clips  50 , so the fixed hook height is a restraining parameter which inhibits the design of the new tiles and tiles of different styles. 
     Both the prior art clips  5  and  50  attempt to hold the tiles  1 ,  2  rigidly in place. However, the rafters of the roof do not form an entirely uniform surface. Battens where present are only rough sawn and are not formed from dressed timber, the plywood of roof decks is not of exactly uniform thickness, and so on. All of these dimensional tolerances result in a roof surface which is slightly undulating. Once the tiles are laid and the clips  5 ,  50  installed, the clips  5 ,  50  are covered from view by overlapping portions of adjacent tiles. As a consequence a person, such as a tiler, waking on the tiles after the clips  5 ,  50  are installed, by treading on the tile upper surface can bring the lower surface of that tile into contact with the top of the rigid hook  7 ,  57 . Thus the trod on tile is sandwiched between the tiler&#39;s foot and the hook  7 ,  57 . Often times this compressive force is enough to break a tile. 
     In this connection it should be noted that the sloping tiles  1 ,  2  are the only tiles upon which a tiler, or other person on a roof, walks. Such a person never walks on the ridge tiles at the intersection of two opposed roof surfaces. This is because the ridge tile is very narrow and to walk along ridge tiles is akin to walking along a tightrope (and thus extremely dangerous). Instead a person walking along a ridge puts one foot on the sloping tiles adjacent one side of the ridge and the other foot on the sloping tiles adjacent the other side of the ridge. Thus the ridge tiles are straddled rather than walked on. As a consequence of this universal practice, ridge tiles have different requirements from those of sloping tiles. 
     Turning now to  FIGS. 4-7 , a first embodiment of the present invention will now be described. The tiles  1  and  2 , the batten  3  and the nail  4  are as before. The clip  205  of the first embodiment is fabricated in two pieces by injection moulding utilising plastics material. A plastics material such as glass filled nylon is advantageous because the material has a “memory” and will return to its original dimensions if stretched or extended. 
     The clip  205  is formed from an upper portion  201  illustrated in  FIG. 5  and a lower portion  202  illustrated in  FIG. 4 . The upper portion  201  includes a hook  207  from which extends an upper strap  218  which is provided with a plurality of saw tooth serrations  219  which are located between a pair of stiffening ribs  220 . The lower portion  202  includes a base  206  from which extends a lower strap  218  which terminates in a ratchet housing  229  having a through aperture  222 . 
     As seen in  FIG. 6 , the upper strap  218  is able to be passed downwardly through the through aperture  222  in the ratchet housing  229  such that the serrations  219  engage with the ratchet mechanism and prevent upwards movement of the upper strap  218 . That is, the upper strap  218  (and hence the hook  207 ) are only able to move downwardly in  FIG. 6  and not upwardly, this direction of movement being indicated by an arrow in  FIG. 6 . 
     Preferably, the nail  4  is supplied already at least partially inserted into the base  206  so that the clip  205  and nail  4  form an assembly which can be handled by the tile installer. 
     A major advantage of the clip  205  of the first embodiment is that the distance between the hook  207  and the base  206  is adjustable, thereby enabling the clip  205  to be used with a wide range of tile sizes, shapes and configurations. Prior to installation, the hook  207  is spaced from the base  206  by a maximum extent. As seen in  FIG. 7 , the nail  4  is driven home into the batten  3 , and then the hook  207  is pushed downwardly in the direction of the arrow in  FIGS. 6 and 7  so as to engage the hook  207  with the tile  1 . 
     A clip substantially in accordance with that illustrated in  FIGS. 4-7  was used to fabricate a test roof five ridge tiles in length and four rows of tiles in width with a pitch of 18°, rafters at 600 mm intervals and terra cotta roof tiles. The test roof was tested in accordance with Australian and New Zealand standard AS/NZS 2050-2002 (Tests for Roof Tiles) by CSIRO MANUFACTURING &amp; INFRASTRUCTURE TECHNOLOGY, North Ryde, Sydney, Australia. The clips were found to have an average tensile strength of approximately 180 Newtons. The test roof passed all cyclic pressure tests (8,000 cycles at 1.48 kPa to 1 cycle at 3.70 kPa). After completion of the tests the load on the roof was increased to 4.05 kPa at which point the perimeter seal (rather than the tiles or clips) failed. These test results substantially exceed loadings likely to be experienced during cyclonic (hurricane) storm events. 
     In the event of a cyclone, the weakest member in the assembly is the nail  4  which is liable to be bent upwardly, thereby releasing the tile  1  slightly and allowing the tile  1  to move upwardly to a small extent, often sufficient to relieve the momentary high stress at the peak of the storm. Thereafter the tiles can be re-seated and the hook  207  fully re-engaged with the tile  1  merely by pushing the hook  207  downwardly so as to further engage the strap  218  with the ratchet housing  229 . Thus the now slightly bent nail  4  can be retained, without removal or straightening, for further service. Indeed the nail  4  may be strengthened by work hardening as a result of the deformation brought about by the slight bending. 
     Furthermore, in those instances where the battens are fabricated from hardwood, it is difficult to engage the batten with sufficient force if using something (such as a wire) other than a metal fastener. Thus clips which do not incorporate a metal fastener with a shank which penetrates the batten, are contra-indicated. 
     An important consequence of the base  206  extending at right angles to the strap  218  and having a free end which abuts the batten, is that the length of the base  206  determines the set out of the strap  218  from the batten  3 . Consequently, the tiler does not need to estimate the amount of force required to position the clip  205  as is the case with the prior art clip  5  of  FIG. 2  (where the distance X is determined in large part by the intensity with which the wail  4  is stuck). Instead the tiler merely drives the nail  4  home so as to bring the head  34  into contact with the base  206  as seen in  FIG. 7 . 
     Turning now to  FIGS. 8-16 , a deck clip  305  of a third embodiment suitable for rooves having a deck  51  is illustrated. As before the clip  305  is formed from an upper portion  301  and a lower portion  302 . The upper portion  301  includes a hook  307 , teeth  319  and stiffening ribs  320 . The lower potion  302  includes a base  306  which extends at right angles from the adjustable strap  318  which interconnects the hook  307  and base  306 . The strap  318  includes a ratchet housing  329  having a through aperture  322 . 
     As best seen in  FIGS. 9 and 12 , the ratchet housing  329  preferably includes a release tab  330 . This enables a screw driver or like implement to be inserted from below into the aperture  322  and thereby release the ratchet pawl (not illustrated). This may be necessary during roof repairs, for example. 
     The strap  318  is preferably a slightly loose fit within the aperture  322  and so can be worked slightly to the left or right as seen in  FIG. 16 . This better enables the desired surface contact between the hook  307  and the tile  1  to be achieved. This loose fit does not in anyway diminish the inability of the strap  318  to be moved upwardly away from the base  306 . 
     As best seen in  FIG. 8  the base  306  has a pair of apertures  340  each of which is intended to receive a corresponding nail  4  by means of which the clip  305  is secured to the deck  51  as seen in  FIG. 16  (only the heads  34  of the nails  4  being visible). In addition, the base  306  is tapered so as to allow for the difference in slope between the tile  1  and the deck  51  as explained above in relation to  FIG. 3 . This means that the hook  307  fits in an entire surface contact with the tile  1 , not an edge contact as explained above in relation to  FIG. 3 . 
     It will be appreciated from the above that in the first embodiment of  FIGS. 4-7 , the hook  207  is substantially parallel to the base  306  whilst for the second embodiment of  FIGS. 8-16  the hook  307  is substantially perpendicular to the base  306 . 
     The above described and illustrated embodiments provide a number of substantial advantages over the prior art. 
     Firstly, the clips  205  and  305  are easily installed since the hook  207 ,  307  is pushed downwardly to engage the tile  1  after the clip  205 ,  305  has been secured to the batten  3  or deck  51  respectively. Conversely in the prior art the hook is engaged with the tile and then the nail(s) is/are driven home. 
     Secondly, the clip  205  allows the nail  4  to be driven fully home since the spacing between the hook  207  and the batten  3  is determined by the specific length of the base  206 , and not by the force (or cumulative force) applied to the nail. Thus the overall installation is much easier. 
     Thirdly, since the distance between the hook  207 ,  307  and the base  206 ,  306  is adjustable, the one roofing clip can be used for a wide variety of tiles and in a wide variety of installations. Thus the prior art problems of the large inventory of different types of clip and a stultifying effect on tile design and innovation are overcome. 
     Furthermore, the prior art problem of sloping tiles breaking if persons walk on them is also overcome. This is because the hook  207 ,  307  instead of being rigidly secured to the batten or roof deck (and thereby forming a potential tile fracture site) has a certain amount of “give”. This is inherent in the ratchet mechanism  229 ,  329  which allows the hook  207 ,  307  to depress when a vertically downward force (or force component) is applied to it. Tilers are audibly reminded of this advantage when walking on sloping tiles secured with the roof clips of the present invention since the sound of the ratchet mechanism tightening by a notch or two can be heard (rather than the sharp snap of terra cotta tiles breaking). It is therefore advantageous after the initial installation for the tile which overlies each clip to be trodden on by the tiler as a means of further tightening the installation. 
     This is to be contracted with the disclosure of U.S. Pat. No. 4,047,353 (Aarons) which relates to ridge caps which are normally secured by mortar. The use of mortar teaches away from the present invention since sloping tiles are not secured by mortar, thus the problem solved by the U.S. Pat. No. 4,047,353 specification doe not arise with sloping tiles. Still further, the mortar is of little use against high winds since it is incapable of providing any tensile strength (only compressive strength). Furthermore, the clips of this US patent are not concealed by adjacent tiles but are instead visible after installation (see  FIGS. 4 and 5  in this connection). This lack of concealment is not relevant for the crest of the ridge since such a crest is not normally visible from ground level. However, such visible clips are entirely inappropriate for sloping tiles on aesthetic grounds. A further contra-indication is the use of a plastic washer  54  (see  FIGS. 2 and 5 ) to act as a water barrier. For sloping tiles such a water barrier would add substantially to the cost of a roof because of the large number of sloping tiles in any roof compared with the relatively small number of ridge tiles. 
     The foregoing describes only two embodiments of the present invention and modifications, obvious to those skilled in the roofing arts, can be made thereto without departing from the scope of the present invention. For example, a threaded fastener such as a self tapping screw is able to be used in place of the nail  4 . 
     The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “including” or “having” and not in the exclusive sense of “consisting only of”.