AU2005201708A1 - Device and method for connecting a roof member to a wall - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant Actual Inventors Address for Service: Invention Title: Robert Ritchie 29 Kremzow Road, Brendale, Queensland, 4500, Australia Robert Ritchie Kenneth John McGrogan CULLEN CO Patent Trade Mark Attorneys, 239 George Street Brisbane Qld 4000 Australia Device and method for connecting a roof member to a wall The following statement is a full description of this invention, including the best method of performing it, known to the applicant: o This invention relates to a device and method for connecting a roof member to a wall. In particular, the invention is directed to the use of a 'tie-down" rod to secure a roof truss to a bondbeam formed at the top of a block wall, although the invention is not limited thereto.

00 BACKGROUND ART 0In many regions, building regulations require that a roof be securely connected to the structure on which it rests, in order to withstand the uplift forces n generated in high winds. In timber framed buildings, roof trusses are commonly tied O 10 to the floor by tie-down rods passing vertically through the wall frames.

In block wall buildings constructed from concrete or clay blocks, the roof can be connected to a bondbeam (also known as a bond beam) formed at the top of a block wall. The bondbeam is typically formed in an upper course (or courses) of blocks in the wall by inserting steel reinforcement rods horizontally through the upper course(s). (Portions of the blocks may be knocked out to permit the reinforcing rods to pass through the blocks.) The blocks in the upper course(s) are then filled with concrete so as to form a continuous reinforced concrete block course around the top of the masonry wall. The bondbeam is also known in the trade as a masonry lintel.

It is known to use a plate (or "cleat") to secure a roof member, such as a roof truss, to a reinforcing rod in a bondbeam. The plate has an opening at its lower end to permit it to be threaded onto the reinforcing rod. The plate has a portion which protrudes above the wall and is later fixed to a respective roof truss, e.g. by bolting or clamping.

However, such plates are tedious and time-consuming to install. The correct number of plates must be threaded onto an end of the reinforcing rod, and positioned at the desired locations of the respective roof trusses by sliding them along the reinforcing rod, before the concrete is poured to form the bondbeam. As rods are often supported on wire slings in the blocks, it is necessary to lift the rod to slide the plates into position. The plates also have to be held or moved to an upright orientation while the concrete sets.

In some instances, unscrupulous builders may be tempted to simply insert some or all of the cleats into the wet concrete without threading them onto a O reinforcement rod beforehand. Once the concrete has set, it is not possible to tell by visual inspection whether the cleats have been threaded onto the reinforcing rods, yet such cleats are likely to be pulled loose from the bondbeam when the roof is subjected N to high wind loads.

Australian patents nos. 2003100210 and 2003235057, whose O disclosures are incorporated herein by reference, describe truss brackets for securing a 0 roof member to a block wall.

OThe truss bracket of Australian patent no. 2003235057 comprises a U- I shaped member having aligned apertures in the bottom of its sidewalls. In use, a reinforcing rod is threaded through the apertures in the U-shaped member, which is then moved along the reinforcing rod to the desired position. A roof truss or other roof member is placed between the upstanding arms of the U-shaped member, and the arms are then folded over the truss and nailed to it. This truss still has the disadvantage that it must be threaded onto an end of the reinforcing rod. It must also be positioned before the rod is fixed in the block cavity and the roof trusses are placed on the block wall, as these would impede its movement along the rod.

Australian innovation patent 2003100210 teaches a method of connecting a roof truss to a bondbeam by using a strap which is passed under the reinforcing rod, and has its ends folded over, and nailed to, the roof truss. Although the strap of innovation patent 2003100210 can be applied to the reinforcing rod intermediate its ends, it is still very difficult and awkward to feed the strap around the bottom of the reinforcing rod, and back over the top of the roof truss. Furthermore, under high wind loads such as occur in cyclones, the nails fastening the strap to the roof truss may be pulled loose.

Another disadvantage of known systems for securing a roof truss to a bondbeam is that they are effectively limited to bondbeams formed in the uppermost course of blocks in the wall.

It is an aim of this invention to overcome or ameliorate at least some of the disadvantages described above, or at least provide the consumer with a useful choice.

0 SUMMARY OF THE INVENTION In one broad form, the invention provides a device for connecting a r roof member to a wall, comprising a substantially rigid elongate member having a hook portion at one end thereof for operative engagement with a first, generally horizontal, reinforcing rod in the wall, and attachment means at its opposite end 00 adapted for connection to the roof member.

0 The invention also provides a building construction comprising a block wall having a first bondbeam formed in a first upper course thereof, the bondbeam i including at least a first, generally horizontal, reinforcing rod; a roof member above 0 the wall; and a substantially rigid, generally upright, elongate member securing the roof member to the wall, the elongate member having a hook portion at its lower end engaged with the first reinforcing rod intermediate the ends of the first reinforcing rod, and attachment means at its upper end connected to the roof member.

The invention has the advantage that the elongate member can be hooked onto the reinforcing rod from above, at any desired location along the length of the reinforcing rod, in a quick and simple manner. That is, it need not be threaded onto an end of the reinforcing rod. Moreover, the elongate member can be hooked onto the reinforcing rod without lifting the reinforcing rod from the blocks. The elongate member can be made long enough to hook onto a reinforcing rod in a course of blocks below the uppermost course.

In yet another form, the invention provides a method of connecting a roof member to a block wall having at least a first, generally horizontal, reinforcing rod in a first upper course thereof, the method comprising the steps of providing a substantially rigid elongate member having a hook portion at one end thereof and attachment means at its opposite end; engaging the first reinforcing rod intermediate its ends with the hook portion; positioning the elongate member in a generally upright orientation adjacent the roof member; and connecting the attachment means to the roof member.

The method normally includes the step of placing concrete around the first reinforcing rod to form a bondbeam in the first upper course.

The block wall may have a second, generally horizontal, reinforcing rod in a second upper course thereof, above the first upper course. Advantageously, 0 O the elongate member has a projection intermediate its ends which engages the second reinforcing rod. The projection may suitably be a finger-like portion angled obliquely to the elongate member and opposed to the hook portion.

Preferably, the hook portion of the elongate member is hooked under the first reinforcing rod and the projection is hooked over the second reinforcing rod, O to thereby connect the two bond beams and limit vertical separation of the first and 0 second reinforcing rods. The tie-down device eliminates the need for the clips Ocommonly used to secure reinforcing rods in separate bondbeams together.

n Furthermore, this arrangement also serves to retain the elongate member automatically in an upright orientation while the bondbeam is formed.

In one embodiment, the attachment means comprises a plate parallel to the longitudinal axis of the elongate member and juxtaposed with the roof member.

The plate may have at least one aperture therein for a fastener connecting the roof member and the plate.

In another embodiment, the attachment means comprises a threaded upper end portion of the elongate member adapted to receive a clamp or other fitting for the roof truss. For example, a hold-down plate can be threaded on the elongate member and positioned on top of the roof member. The hold-down plate is secured by a nut screwed onto the threaded upper end portion of the elongate member, to thereby restrict upward movement of roof member.

In order that the invention may be more fully understood and put into practice, preferred embodiments thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a tie-down device according to one embodiment of the invention.

Fig. 2 is a fragmentary cutaway perspective view of a building construction showing the tie-down device of Fig. 1 in use.

Fig. 3 is a sectional elevation of a building construction showing a modified version of the tie-down device of Fig. 1 in use.

Fig. 4 is a perspective view of a tie-down device according to another t-) 0 o embodiment of the invention.

Fig. 5 is a fragmentary cutaway perspective view of a building construction showing the tie-down device of Fig. 4. in use.

Fig. 6 is a sectional elevation of a building construction showing a modified version of the tie-down device of Fig. 4 in use.

00 0 DESCRIPTION OF PREFERRED EMBODIMENTS oFig. I illustrates a tie-down device 10 for connecting a roof member to ifl a block wall, according to a first embodiment of the invention. The device 10 is in the 0 O 10 form of an elongate member, such as a rod or bar 9, and has a hook 11 at one end S(which, in use, is the lower end). The hook 11 can be formed by bending the rod or bar 9 into a "J-shape".

The tie-down device 10 also has at its other end, an attachment means in the form of a plate 12. The plate 12 is preferably co-planar with the bar 10, and is connected thereto by welding the top end of the bar in a recess formed in the bottom of the plate 12. Alternatively, the plate 12 may be welded to the side of the bar 10, so that it is parallel to the axis of the bar. The plate 12 is provided with a bolt hole 13 to receive a fastener, as described in more detail later. The plate 12 may also be provided with a locating hole 13a.

The tie-down device 10 also comprises a projection 14 in the form of a short length of bar or rod welded to the bar 9 at an oblique angle, as illustrated in Fig.

1. The projection 14 is opposed to the hook 11, and generally co-planar therewith.

Fig. 2 illustrates the use of the tie-down device 10 of Fig. I to secure a roof member 26 to a wall 20. As shown in Fig. 2, a through cavity 21 is formed in a course of blocks, being the third highest course, in preparation for the formation of a bondbeam in that course. A reinforcing rod 22 is laid in a generally horizontal orientation in the cavity 21.

A cavity 23 is also formed in the uppermost course of blocks in preparation of the formation of a bondbeam in that course as well. A reinforcing rod 24 is laid in a generally horizontal orientation in the cavity 23. Both the horizontal rods 22 and 24 can be suspended in their respective cavities 21,23 by spaced wire slings 25. (For clarity, only one sling 25 in the upper cavity 23 is shown).

Q- Each tie-down device 10 is applied to the block wall at a desired location, namely adjacent a roof truss 26 (or, if the roof trusses have not been laid on r the wall, each tie-down device 10 is positioned adjacent the intended location of a crespective roof truss). The blocks forming the wall are normally open at their top and bottom, thereby providing vertical throughholes in the block wall. The tie-down O device 10 is manually inserted into a vertical throughhole from above, so that the hook

O

11 engages under the lower reinforcing rod 22. The upper reinforcing rod 24 is omanually depressed a sufficient distance to pass it under the projecting finger 14. As the height of the blocks is known, the device 10 is dimensioned so that the distance 0 between the hook 11 and the crook formed by the finger 14 is approximately equal to the distance between the upper and lower reinforcing rods 24,22. Preferably, the distance between the hook and the crook is slightly less than the normal distance between the two reinforcing rods, so that they are resiliently held by the tie-down device. This not only assists in maintaining the tie-down device 10 automatically in an upright orientation, but also serves to hold the reinforcing rods 22,24 at the correct spacing and eliminates the need for the separate clips which are commonly used for this purpose.

The cavities 21,23 are filled with concrete after the tie-down rods have been hooked onto the reinforcing rods 22, 24. Alternatively, the tie-down rods can be hooked firstly onto the reinforcing rod 22 and the cavity 21 filled with concrete. The tie-down rods 10 can remain in place while the two top courses of blocks are added, and then their projections 14 hooked onto the reinforcing rod 24 before the cavity 21 is filled with concrete.

It is only necessary to secure the lower reinforcing rod 22 to the floor of the building, as the tie-down devices 10 will serve to secure the upper reinforcing rod 24 to the lower reinforcing rod 22, and hence to the floor of the building.

The attachment plate 12 is abutted against the roof truss 26, preferably against a nail plate 27 for added strength. Typically, a nail is inserted through the locating hole 13a and into the truss 26 to hold the plate 12 in position. A hole is drilled through the roof truss 26 in alignment with the bolt hole 13 in the attachment plate, and a suitable fastener, such as a bolt is passed through the attachment plate 12 and the truss 26.

oIn a shortened version of the tie-down device of Fig. 1, the projection 14 is omitted, and the tie-down device is hooked to a reinforcing rod in a bondbeamrn in r the second highest course of blocks, as illustrated in Fig. 3. Alternatively, using an ceven shorter version of the tie-down device (not shown), the tie-down device can be hooked onto a reinforcing rod in the uppermost course of blocks.

OO Fig. 4. illustrates a tie-down device 10a according to a second 0 embodiment of the invention. The tie-down device 10a is similar to that of Fig. 1 in othat it comprises a rigid elongate member in the form of a steel rod or bar 9a having a hook 1 1a at its lower end. The tie-down device 10 Oa also has between its ends, a finger 0 14a projecting obliquely downwardly. The finger 14a is opposed to the hook 1 la, and co-planar therewith. However, instead of the attachment plate 12, the tie-down device has a threaded upper end 15 to facilitate connection to a roof member, such as a roof truss 26 as illustrated in Fig. The installation of the tie-down device 10a in the block wall shown in Fig. 5 is similar to that described above in relation to Fig. 2, and need not be repeated.

The tie-down device 10a is installed adjacent its respective roof truss 26 so that a roof clamp (or other fitting) can be applied to the truss 26 and fastened to the upper end of the tie-down device In a shortened version of the tie-down device of Fig. 4, illustrated in Fig. 6, a tie-down device I O0c is adapted to hook onto a reinforcing rod in a bondbeam formed in the second highest course of blocks. The upper portion of the tie-down device 10c is angled to be perpendicular to the truss 26. An apertured plate 28 is placed over the upper end 15 of the tie-down device 10c and extends over the top of the truss 26. A nut 29 is then screwed onto the threaded end 15 of the tie-down device and tensioned so that the truss 26 is retained securely on the wall.

In yet another modified version of the tie-down device of Fig. 4, the projecting finger 14a is omitted so that the device engages a reinforcing rod in a bondbeam in only one course of blocks. This is typically the uppermost, or the second or third highest course of blocks.

The foregoing describes only some embodiments of the invention, and modifications which are obvious to those skilled in the art may be made thereto without departing from the scope of the invention. For example, the projecting finger int 9 0 o 14 may be of curved or angled configuration.

SFurthermore, the elongate member 9 may be in the form of a plate having an oblique slot in a lower portion thereof to form a hook portion on the plate.

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Claims (20)

1. A device for connecting a roof member to a wall, comprising ca substantially rigid elongate member having a hook portion at one end thereof for operative engagement with a first, OO generally horizontal, reinforcing rod in the wall, and 0 attachment means at its opposite end adapted for connection to the roof o member. tc O 10

2. A device as claimed in claim 1, wherein the elongate member has a projection intermediate its ends for operative engagement with a second, generally horizontal, reinforcing rod in the wall.

3. A device as claimed in claim 2, wherein the hook portion is adapted to hook under the first reinforcing rod and the projection is adapted to hook over the second reinforcing rod to limit vertical separation of the first and second reinforcing rods.

4. A device as claimed in claim 2 or 3, wherein the projection is a finger-like portion angled obliquely to the elongate member and opposed to the hook portion.

A device as claimed in any preceding claim wherein the attachment means comprises a plate parallel to the longitudinal axis of the elongate member, the plate having at least one bolthole therein.

6. A device as claimed in any one of claims 1 to 4, wherein the attachment means comprises a threaded end portion of the elongate member, adapted to receive a nut and hold-down plate thereon.

7. A building construction comprising a block wall having a first bondbeam formed in a first upper course thereof, the bondbeam including at least a first, generally horizontal, reinforcing rod; a roof member above the wall; and 0 a substantially rigid, generally upright, elongate member securing the roof member to the wall, the elongate member having a hook portion at its lower end engaged with the first reinforcing rod intermediate the ends of the first reinforcing rod, and attachment means at its upper end connected to the roof member. 00 OO 0

8. A building construction claimed in claim 7, wherein o the block wall has a second bondbeam formed in a second upper course in thereof above the first upper course, the second bondbeam including at least a second, O 10 generally horizontal, reinforcing rod, and the elongate member has a projection intermediate its upper and lower ends engaged with the second reinforcing rod in the wall.

9. A building construction as claimed in claim 8, wherein the hook portion is hooked under the first reinforcing rod and the projection is hooked over the second reinforcing rod to limit vertical separation of the first and second reinforcing rods.

A building construction as claimed in claim 9, wherein the projection is a finger-like portion angled obliquely to the elongate member and opposed to the hook portion.

11. A building construction as claimed in any one of claims 7 to 10, wherein the attachment means comprises a plate parallel to the longitudinal axis of the elongate member and juxtaposed with the roof member, the plate having at least one aperture therein, further comprising a fastener passing through the roof member and the plate.

12. A building construction as claimed in any one of claims 7 to 10, wherein the attachment means comprises a threaded end portion of the elongate member having a nut and hold-down plate thereon, the hold-down plate being positioned on the roof member to restrict upward movement thereof

13. A method of connecting a roof member to a block wall having at least a first, O generally horizontal, reinforcing rod in a first upper course thereof, the method comprising the steps of providing a substantially rigid elongate member having a hook portion at one end thereof and attachment means at its opposite end; engaging the first reinforcing rod intermediate its ends with the hook portion; OO positioning the elongate member in a generally upright orientation adjacent 0 the roof member; and Oconnecting the attachment means to the roof member.

14. A method as claimed in claim 13, including the step of placing concrete around the first reinforcing rod to form a bondbeam in the first upper course.

A method as claimed in claim 13, wherein the block wall has at least a second, generally horizontal, reinforcing rod in a second upper course thereof above the first upper course, and the elongate member has a projection intermediate its ends; the method including the step of engaging the projection with the second reinforcing rod.

16. A method as claimed in claim 15, wherein the hook portion is hooked under the first reinforcing rod and the projection is hooked over the second reinforcing rod to limit vertical separation of the first and second reinforcing rods.

17. A method as claimed in claim 15 or 16, wherein the projection is a finger- like portion angled obliquely to the elongate member and opposed to the hook portion.

18. A device for connecting a roof member to a wall, the device being substantially as described herein with reference to Fig. 1 or Fig. 4.

19. A building construction substantially as described herein with reference to any one of Figs. 2,3,5 or 6. n 13 o

20. A method of connecting a roof member to a wall, the method being Ssubstantially as described herein with reference to the accompanying drawings. 00 DATED this 22 n d day of April 2005 ROBERT RITCHIE Ci by his Patent Attorneys SCULLEN CO. ci