WO2009065185A1

WO2009065185A1 - Roof anchor method and apparatus

Info

Publication number: WO2009065185A1
Application number: PCT/AU2008/001733
Authority: WO
Inventors: Arvo Poldmaa
Original assignee: Poldmaa, Kathleen; Poldmaa, Robyn; Poldmaa, Daniel
Priority date: 2007-11-22
Filing date: 2008-11-24
Publication date: 2009-05-28
Also published as: AU2008328532B2; AU2008328532A1

Abstract

A roof anchor assembly for fitment to a roof support structure having an underside surface is disclosed. The roof may be fully or partially covered with roof covering material. The roof anchor assembly includes a roof anchor and an anchor block; the roof anchor having a shaft for insertion through a hole in the covering material and roof support structure. The hole is capable of receiving the shaft; and the said anchor block capable in one orientation of being inserted through the hole in the roof covering material and roof support structure independently of the roof anchor and prior to insertion of the shaft of the roof anchor therethrough. Furthermore, the anchor block has means to suspend it whilst it is thus inserted through the hole, such means also functioning to draw the anchor block up into a second orientation to the underside surface of the roof support structure once it has been fully inserted, so that it cannot be withdrawn. The anchor block has a second hole therein capable of fixedly engaging the shaft of the roof anchor once the anchor block is thus drawn up to the underside surface of the roof support structure. The second hole in the anchor block is aligned with the hole in the covering material and roof support structure by virtue of being thus drawn up in the second orientation, so that upon insertion of the shaft of the roof anchor in the hole in the covering material and roof support structure, it may be fixedly engaged with the anchor block, in order that the roof anchor is then mounted on the support structure,

Description

ROOF ANCHOR METHOD AKD APPARATUS TECHNICAL FIELD

The present invention relates to roof anchors for attaching devices, apparatus or equipment to a roof support structure and, more particularly, to a method or 5 apparatus for installing a roof anchor to the support structure. The devices, apparatus or equipment to be attached may include safety equipment such as a safety harnesses, ropes or other safety devices adapted to secure a roof worker, including a safety barrier or fence, or may include other roof mounted fittings such as water heaters or solar panels. 0 BACKGROUND ART

Conventional roof anchoring devices require access to the roof support structure such as a purlin or rafter. Direct access to the support structure is generally required and involves mounting the roof anchor prior to the application of the external covering of the roof such as tiles, sarking, sheeting or other cladding so5 that upon application of the external covering to the support structure, the roof anchor extends proud of the external covering.

However, if the external covering has already been applied to the roof support structure, then at least one unit of the external covering such as a tile or single sheet of covering must be removed to provide access to the roof support structure. Where0 part of the external covering must be removed to provide access to the roof support structure, such as for example will be the case for a completed building to which repairs, improvements or renovations are required, this may be impractical or inconvenient. Thus, for example, where large units of sheeting form the external covering of the roof, considerable time and effort may have to be expended tos remove a single unit to gain access to the roof support structure. Furthermore, there is also a risk that damage to the covering may occur, or more particularly, once it is re-laid, the covering might not properly seal against the elements.

A solution has been provided to some extent in our earlier Australian patent No 2001283678. This patent inter alia, provided for a method for mounting a roof0 anchor on a roof support structure having an underside surface, the roof fully or partially covered with roof covering material, the roof anchor including an attachment means and a shaft, in which the method included the following steps: a) Making a first hole in the covering material and the roof support structure, which first hole is capable of receiving the shaft;

b) Forming an aperture in the covering material adjacent the first hole and the roof support structure; c) By means of a hand tool, inserting an anchor block, having a second hole capable of fixedly engaging the shaft, through the aperture and locating the anchor block at the underside surface such that the first and second holes are in registry; and d) Inserting the shaft through both the first and second holes whereby to fixedly engage the roof anchor to the anchor block, such that the roof anchor is mounted on the roof support structure, and then withdrawing the hand tool, which was used

Whilst this earlier patent provided a useful solution, it relied on the use of a tool which was inserted through a second hole cut in the covering material adjacent the first hole for receiving the shaft of the anchor. It was felt that there were disadvantages to this method, not only because of the need to provide an additional tool at some expense which could be easily lost, but also as a result of the time required to cut a second aperture and the need to aslo seal this second aperture. Consequently, consideration was given to ways in which the system could be improved.

It is therefore an object of the present invention to provide a method and apparatus which ameliorates one or more of the abovementioned disadvantages associated with the prior art.

The above description of the prior art is not intended to be, nor should it be interpreted as, an indication of part or all of the common general knowledge pertaining to the invention, but rather to assist the person skilled in the art in understanding the developmental process which lead to the invention. Furthermore, it should also be understood that whilst the invention relates primarily to the attachment of devices to a roof as described, the invention will also be applicable in many instances to situations where attachment of a device to any hollow structure is required, whether a wall or ceiling for example. Thus any reference to a roof is also meant to encompass reference to any structure, where, by suitable adaptation the invention may also be utilised. DISCLOSURE OF THE INVENTION

According to the present invention, there is provided a roof anchor assembly for fitment to a roof support structure having an underside surface, said roof fully or partially covered with roof covering material; the roof anchor assembly including a

5 roof anchor and an anchor block; the roof anchor having a shaft for insertion through a hole in the covering material and roof support structure, which hole is capable of receiving the shaft; said anchor block capable in one orientation of being inserted through the hole in the roof covering material and roof support structure independently of the roof anchor and prior to insertion of the shaft of the roof0 anchor therethrough; the anchor block further having means to suspend it whilst it is thus inserted through the hole, such means also functioning to draw the anchor block up into a second orientation to the underside surface of the roof support structure once it has been fully inserted, so that it cannot be withdrawn, the anchor block having a second hole therein capable of fixedly engaging the shaft of the roofs anchor once the anchor block is thus drawn up to the underside surface of the roof support structure, the second hole in the anchor block being aligned with fhe hole in the covering material and roof support structure by virtue of being thus drawn up in the second orientation, so that upon insertion of the shaft of the roof anchor in the hole in the covering material and roof support structure, it may be fixedly engaged0 with the anchor block, in order that the roof anchor is then mounted on the support structure.

The anchor block may be any suitable shape, for example having a square or rectangular cross-section. Preferably, the anchor block however is generally cylindrical in shape, having a cross-sectional shape which is generally circulars except for a flattened region forming a flat surface along the length of the cylinder, being along one "side" thereof. It is this flattened surface which abuts the underside surface of the roof support structure once the anchor block is brought into location below the hole utilising the suspension means to draw it up . It will thus be appreciated that in this preferred form of the invention, the generally cylindrical0 anchor block may be easily inserted lengthwise through the hole in the first orientation and given suitable means by which it is suspended, as discussed below, allowed to fall cross-ways into the second orientation ready to be drawn up against the underside surface of the roof support structure.

The geometry is such that the effective diameter of the cylindrical block need only5 be sufficiently larger than the diameter of the second hole located therein to provide integrity for the anchor block itself and consequently the hole to be formed in the covering material and roof support structure needs only to be of sufficient diameter to let the anchor block slide through and hence will not need to be that much larger than the shaft of the roof anchor itself.

Preferably the means for suspending the anchor block so that it may be first inserted through the hole in the first orientation is in the form of a pair of flexible elongate ties, such as wire, fine cord or the like. With advantage, the ties maybe elastic, for example made of high strength rubber or polymer material. For ease of use the ties may be joined at the top thereby forming a convenient loop by which to more easily hold the anchor block. It will readily appreciated that by using a pair of such ties, whether individually or forming a single loop, strategically located, it will be possible to allow the anchor block to fall through the hole in the first orientation but be suspended in the second orientation ready for drawing back up against the underside surface of the roof support structure, ie the anchor block generally lying horizontal, with the flat surface uppermost. Thus, by locating the ties on opposite sides of the second hole in the anchor block, that hole will pretty much automatically align with the hole in the covering material and roof support structure, so that the shaft of the roof anchor may be easily engaged with the second hole in the anchor block, as it is inserted through the bole in the covering and support structure. By providing flexible ties in the form described, they will easily align with the flat side of the cylinder so as to also pass through the hole in the covering material and roof support structure without any appreciable interference.

In a particularly preferred embodiment, a simple ring or washer may be employed in which each of the support ties (or individual legs of a single loop if employed) passes though respective holes on opposite sides of the washer. The washer will have a central hole sufficient for the shaft of the roof anchor to pass through and an external diameter greater than the diameter of the hole in the covering material and roof support structure. In this form, such a washer serves two functions. Firstly it prevents the anchor block from falling completely through the hole if the installer inadvertently lets go of the support ties as the anchor block is passed through the hole, or after it has been fully inserted. Secondly, once the anchor block is brought up against the underside surface of the roof support structure, the washer may be slid down the support ties to the upper side of the hole so as to retain the anchor block against the underside without the need for using hands to hold the ties whilst inserting the shaft of the roof anchor in the hole and engaging with the anchor block. This will be more readily achieved if there is a little interference fit between the ties and the holes in the washer which they pass through. In this respect, ties having elastic properties will be advantageous. Once the shaft engages with the anchor block the support ties can be snipped off, and the excess ties removed.

Preferably attachment of the anchor block to the shaft of the roof anchor is achieved by means of complementary threads located on the one hand about the end of the shaft of the roof anchor and on the other hand, internally in the second hole located in the anchor block. That is to say, the attachment means in the form of the anchor block may be threadably fixed to the shaft as is standard in the art whereby the fixing means includes a male threaded portion and a female threaded socket portion. Preferably, me male threaded portion forms part of the shaft and the female threaded socket portion is found in the anchor block. The threaded socket may be machined after the attachment means is formed or may be formed by a threaded insert securable to a pre-existing bore in the anchor block.

The shaft may be in the form of a bolt, the free end of which is threaded for fixed engagement to the anchor block. Alternatively, the shaft may include at its free end spreadable wings adapted for insertion through the second hole thereafter spreadable to engage the underside of the anchor block. However, in the preferred form the shaft includes a threaded bolt section adapted for threaded engagement in the second hole of the anchor block. The roof support structure may include a rafter, purlin or any other form of the roof framework or trass capable of supporting the potentially considerable load which may be placed on the structure in the event of workman falling and relying on the arrangement of the present invention to arrest his fall. The structure may be a purlin. The purlin may have a solid rectangle, C- or channel cross-seetional shape. In the case of a C-purlin, it will be appreciated by a person skilled in the art that only a relatively short shaft may be necessary to extend through the covering material and, the portion of the purlin to which the roof anchor is to be mounted through to the anchor block. Where the roof anchor is to be mounted onto a roof support structure of considerable thickness, such as may be the case where a solid wooden beam is involved, the shaft will need to be correspondingly of longer dimensions to extend through the structure to its underside surface,

The anchor block is preferably prevented from rotation in a horizontal plane where the roof anchor is to be mounted on, for example, a C-purlin. This will be achieved for example by having the anchor block of sufficient length that it is prevented from turning by coming into contact with vertical portions of the purlin. The.invention may include the placement of a weatherproofϊng cover about the shaft to seal the first hole against the ingress of wind and rain. The weather seal may be applied before or after the mounting of the roof anchor assembly to the support structure.

Preferably sealing means are provided about the shaft of the roof anchor to provide a seal about the hole once the roof anchor assembly is fitted. This sealing means is preferably in the form of a sealing washer, the underside of which may have a suitable gasket of compressible material, which may or may not be fixedly attached thereto. Similarly, the compressible gasket material may also have adhesive0 properties to further assist in sealing.

In the case of rooves having other than flat profiles, such sealing washer may also be shaped to correspond to the profile of the covering material , or be made of sufficiently malleable material so as to be able to be made to conform in situ.

Preferably, sealing between the washer and the shaft of the roof anchor is achieveds by means of an O-ring which is compressed upon fitment of the roof anchor assembly.

The roof anchor may include any suitable means for attaching a safety harness, rope, harness or like means of securing a workman to the roof support structure to enable to workman to work safely on the roof. The roof anchor may stand proud ofα the external covering of the roof to present attachment means suitable for securing a safety harness, rope or the like thereto.

The attachment means may comprise one or more salients to which a rope or cable may be secured. The salient may terminate in a bulbous portion to prevent the rope, etc. from working free of the salient. In more conventional roof anchors, the5 attachment means comprises a U- or eye bolt to which the safety harness is securely connected.

An example of a roof anchor which may be used in the present invention is described in international application No. PCT/AU98/00968 the entire contents of which are incorporated herein by reference. 0 According to a second aspect of the invention, there is provided a method for mounting a roof anchor assembly on a roof support structure having an underside surface, said roof fully or partially covered with roof covering material, said roof anchor assembly including a roof anchor and attachment means, the attachment means including an anchor block having suspension means to suspend same, said method including the steps of: a) Making a first hole in the covering material and the roof support structure, which first hole is capable of receiving a shaft of the roof anchor; b) Inserting an anchor block, having a second hole capable of fixedly engaging the shaft, through the hole in a first orientation whilst supporting the anchor block with the suspension means; c) Allowing the block to re-orient to a second orientation, once it has been fully inserted, in which it is drawn up against the underside surface utilising the suspension means such that the first and second holes are in registry and the anchor block cannot be withdrawn; and d) Inserting the shaft through both the first and second holes whereby to fixedly engage the roof anchor to the anchor block, such that the roof anchor is mounted on the roof support structure. The method thus described is applicable to any of the foregoing embodiments, modifying the steps to accommodate the specific embodiment. For example, where a seal is provided, step d) would allow for compression of the sealing gasket as the shaft of the roof anchor is fully engaged with the anchor block.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood from the following non-limiting description of an embodiment of the present invention with reference to the drawings in which:

Fig 1 is a cross-sectional side view of an anchor block assembly having an anchor block with suspension ties for use in a roof anchor assembly according to one embodiment of the invention; Fig 2 is a cross-sectional side view of a roof anchor for use in a roof anchor assembly according to the same embodiment of the invention referred to in Fig 1;

Fig 3 is a cross-sectional side view of a sealing member for use in a roof anchor assembly according to the same embodiment of the invention referred to in Figs 1 and 2; Fig 4 is a plan view of ttie sealing member shown in Fig 3; Fig 5 is a side view of an O-ring for use in a roof anchor assembly according to the same embodiment of the invention referred to in Figs 1 to 4:

Fig 6 is a plan view of the O-ring shown in Fig 5; Fig 7 is a plan view of the anchor block, shown in Fig 1; Fig 8 is a cross-sectional side view of the anchor block of Fig 7, through A-A; Fig 9 is a cross-sectional end view of the anchor block of Fig 7, through A-A;

Fig 10 is a cross-sectional side view of a suspension tie assembly for use with the anchor block of Figs 7 to 9, together forming the anchor block assembly of Fig 1;

Fig 11 is a cross-sectional view of the washer utilised in the suspension tie assembly of Fig 10;

Fig 12 is a plan view of the washer shown in Fig 11;

Fig 13 is a cross-sectional side view of the partly assembled roof anchor comprising the roof anchor of Fig 2, with the sealing member shown in Fig 3 in place on the roof anchor, ready to be attached to the anchor block (not shown); Fig 14 shows a first step in the assembly of the roof anchor assembly, being a cross- sectional view of the anchor block assembly of Fig 1, ready to be inserted in a hole formed in the covering material and roof support structure of a building (not shown);

Fig 15 shows a second step in the assembly following Fig 14, in which the anchor block assembly fully inserted in the hole after being inserted, the anchor block suspended from its ties;

Fig 16 shows a third step in the assembly following Fig 15, wherein the anchor block drawn up to the underside of ihe roof support structure with the washer pushed down on the upperstde of the covering material; Fig 17 shows a fourth step in the assembly following Fig 16, in which the anchor of Fig 13 is ready to be inserted in the hole (the ties lying out of the way to the side and not apparent in this view);

Fig 18 shows a fifth step in the assembly following Fig 17 in which the anchor has been screwed into the hole of the anchor block, the ties having been removed after engagement between anchor and block lias occurred, but prior to being fully tightened;

DETAILED DESCRIPTION OF THE DRAWINGS

Referring generally to Figs 1 to 6 there are shown the various components 5 comprising an anchor assembly 11 according to one embodiment of the invention. The whole assembly is generally referenced 11 and is only shown fully assembled and in situ (but with the ties of the anchor block removed) in Fig 18.

Specifically Fig 1 shows an anchor block assembly 12 for use with the anchor assembly 11. Figs 7 to 12 show, in various elevations, the individual componentso of the anchor block assembly 12. The anchor block assembly 12 comprises an anchor block 13 of generally cylindrical cross-section but having one flat surface 14 located along its length. The block 13 is provided with a central hole 15 which has a female thread therein. The anchor block 13 which is suspended from a pair of ties 16 (in this case forming a loop). The ends of each tie 16 are located in holes 17.5 Any method may be utilised to secure the ties 16, but a preferred form is achieved by crimping, but this not specifically shown. This can be achieved for example by drilling in from the side of the block 13 adjacent where the ties 16 are located in the holes 17 and deforming the hole thus formed slightly to capture the ties 16.

Located about the ties 16 is a holding washer 18, the ties 16 passing throughQ respective holes 19 in the washer 18. Washer 18 is also provided with a central hole 20.

Referring to Fig 2, there is depicted a roof anchor 21 for use with the roof anchor assembly 11. The roof anchor 21 may be one described in patent No. PCT/AU98/00968 referred to above for example. Only the relevant portions5 pertinent to this invention however are described here . Thus the roof anchor 21 includes a shaft 22 which is provided with a male threaded end 23 at its lower end, for engagement with the threaded hole 15 of the anchor block 13, Preferably the shaft is provided with a region 24 having an hexagonal cross section, or at least flat sides as shown, which will allow a spanner or the like tool (not shown) to be0 utilised in screwing the anchor 21 tightly into the anchor block 13.

The shaft is also provided with a step 25 against which a sealing O-ring 26 is located. The O-ritig is shown in side elevation and plan view in Figs 5 and 6 respectively. Figs 3 and 4 show in cross-sectional side and plan view a sealing member generally referenced 27 in the form of a washer 28 and gasket 29 located about its underside. The washer is provided with a centra! hole 30 which has an upper angled surface to accommodate the O-ring 26 when assembled. Gasket 29 is preferably a deformable 5 material such as rubber or rubber based compound, but it may also optionally having an adhesive element, or be comprised entirely of adhesive.

The sealing member 27 is shown in situ on the shaft of the anchor 21 in Fig 13, where it is ready to be assembled with the anchor block 13, once it has been located in place as shown in Figs 14 to 18, io Referring then to Figs 14 to 18, we have illustrated five broad steps in the assembly of the roof anchor assembly 11 utilising the anchor assembly of Fig 1, anchor of Fig 2 and sealing member of Figure 3.

Firstly, as shown in Fig 14, the anchor block assembly 12 is held above a hole 30 formed in the covering material 31 and roof support structure 32 (in this case a C- 16 Purlin) of a building (not shown). The anchor block 13 is oriented perpendicularly, so that it is able to pass through the relatively narrow hole 30, the ties being easily located along the flat side 14 of the anchor block 13 , The anchor is thus lowered through hole 30 in the direction of arrow B.

When fully inserted, step 2 as shown in Fig 15 is reached where the anchor block 20 13 is suspended below hole 30 and will not fall any further by virtue of holding washer 18 having come into contact with the upper surface of the roofing material 31 as shown by arrow C.

As seen in Fig 16, the third step is reached by holding the holding washer 18 down and drawing the ties 16 back up in the direction of arrow D. Because there are two 25 ties 16 located equip-distantly about the threaded hole 15, the anchor block 13 is caused to be drawn against the underside of the roof support structure 32 and locate itself so that threaded hole 15 is in close axial alignment with hole 15. In any event, hole 15 must always be accessible through the slightly larger hole 30, by virtue of the geometry employed.

30 In this way the threaded hole 15 of anchor block 13 is ready to receive the threaded shaft 23 of the anchor 21 as shown in the fourth step of Fig 17. The anchor 21 has the sealing member 27 and O-ring 27 already in place (as was aslo illustrated in Fig 13. Again, the anchor 21 is then lowered in the direction of arrow E, Once the respective threads 15 and 23 are initially engaged, the anchor can be tightened to achieve the resultant assembly as shown in Fig 18, the ties having been cut and discarded once the threads 15 and 23 have been engaged, but prior to be fully tightened, It will appreciated that many modifications and variations may be made to the embodiments described herein by those skilled in the art without departing from the spirit or scope of the invention.

Throughout the specification and claims the word "comprise" and its derivatives are intended to have an inclusive rather than exclusive meaning unless the context requires otherwise.

INDUSTRIAL APPLICABILITY

Tt will be immediately apparent to persons skilled in the art that the roof anchor may provide an anchor point for a variety of activities carried out on roofs. For example, the roof anchor may provide an anchor point for posts supporting fences or other barriers erected for the safety of workmen working on the roof or may be used to secure equipment associated with the actual work on the roof. Moreover, the roof anchor may provide an anchor point for fittings such as solar panels or water heaters required to be mounted on the roof.

Claims

1. A roof anchor assembly for fitment to a roof support structure having an underside surface, said roof fully or partially covered with roof covering material; the roof anchor assembly including a roof anchor and an anchor block; the roof anchor having a shaft for insertion through a hole in the covering material and roof support structure, which hole is capable of receiving the shaft; said anchor block capable in one orientation of being inserted through the hole in the roof covering material and roof support structure independently of the roof anchor and prior to Insertion of the shaft of the roof anchor therethrough; the anchor block further having means to suspend it whilst it is thus inserted through the hole, such means also functioning to draw the anchor block up into a second orientation to the underside surface of the roof support structure once it has been fully inserted, so that it cannot be withdrawn, the anchor block having a second hole therein capable of fixedly engaging the shaft of the roof anchor once the anchor block is thus drawn up to the underside surface of the roof support structure, the second hole in the anchor block being aligned with the hole in the covering material and roof support structure by virtue of being thus drawn up in the second orientation, so that upon insertion of the shaft of the roof anchor in the hole in the covering material and roof support structure, it may be fixedly engaged with the anchor block, in order that the roof anchor is then mounted on the support structure.

2. A roof anchor assembly according to claim 1 in which the anchor block has a shape having a square or rectangular cross-section.

3. A roof anchor assembly according to claim 1 in which the anchor block is generally cylindrical in shape, having a cross-sectional shape which is generally circular except for a flattened region forming a flat surface along the length of the cylinder, being along one "side" thereof, so that in use the flattened surface abuts the underside surface of the roof support structure once the anchor block is brought into location below the hole utilising the suspension means to draw it Up.

4. A roof anchor assembly according to claim 3 in which the generally cylindrical anchor block is easily inserted lengthwise through the hole in the first orientation and by virtue of suitable means by which it is suspended, is allowed to fall cross-ways into the second orientation ready to be drawn up against the underside surface o f the roof support stru cture .

5. A roof anchor assembly according to claim 4 in which the geometry is such that the effective diameter of the cylindrical block need only be sufficiently larger than the diameter of the second hole located therein to provide integrity for the anchor block itself and consequently the hole to be formed in the covering material and roof support structure needs only to be of sufficient diameter to let the anchor block slide through and hence does not need to be that much larger than the shaft of the roof anchor itself.

6. A roof anchor assembly according to any of the preceding claims in which the means for suspending the anchor block so that it may be first inserted through the hole in the first orientation is in the form of a pair of flexible elongate ties, such as wire, fine cord or the like,

7. A roof anchor assembly according to claim 6 hi which the elongate ties are elastic, being made of high strength rubber or polymer material.

8. A roof anchor assembly according to either claim 6 or claim 7 in which the ties are joined at the top for ease of use, thereby forming a convenient loop by which to more easily hold the anchor block.

9. A roof anchor assembly according to any one of claims 6 to 8, in which a pair of ties is used, whether individually or forming a single loop, strategically located, so that it will be possible to allow the anchor block to fall through the hole in the first orientation but be suspended in the second orientation ready for drawing back up against the underside surface of the roof support structure, that is to say, the anchor block generally lying horizontal, with the flat surface uppermost.

10. A roof anchor assembly according to any one of claims 6 to 9, wherein locating the ties on opposite sides of the second hole in the anchor block, that hole will effectively align automatically with the hole in the covering material and roof support structure, so that the shaft of the roof anchor is easily engaged with the second hole in the anchor block, as it is inserted through the hole in the covering and support structure. I LA roof anchor assembly according to any one of claims 6 to 10, in which the flexible ties will easily align with the flat side of the cylinder so as to also pass through the hole in the covering material and roof support structure without any appreciable interference.

12. A roof anchor assembly according to any one of the preceding claims 6 to 11 _» in which a simple ring or washer is employed in which each of the support ties (or individual legs of a single loop if employed) passes though respective holes on opposite sides of the washer. 13. A roof anchor assembly according to claim 12 in which the washer has a central hole sufficient for the shaft of the roof anchor to pass through and an external diameter greater than the diameter of the hole in the covering material and roof support structure.

14. A roof anchor assembly according to claim 13 in which the washer serves two functions, namely firstly to prevent the anchor block from falling completely through the hole if the installer inadvertently lets go of the support ties as the anchor block is passed through the hole, or after it has been fully inserted and secondly, once the anchor block is brought up against the underside surface of the roof support structure, the washer is slid down the support ties to the upper side of the hole so as to retain the anchor block against the underside without the need for using hands to hold the ties whilst inserting the shaft of the roof anchor in the hole and engaging with the anchor block.

15. A roof anchor assembly according to claim 14 in which there is a little interference fit between the ties and the holes in the washer which they pass through to facilitate the operational function as described in claim 14, so that once the shaft engages with the anchor block, the support ties can be snipped off, and the excess ties removed, by virtue of the elastic properties of the ties.

16. Preferably attachment of the anchor block to the shaft of the roof anchor is achieved by means of complementary threads located on the one hand about the end of the shaft of the roof anchor and on the other hand, internally in the second hole located in the anchor block. That is to say, the attachment means in the form of the anchor block may be threadably fixed to the shaft as is standard in the art whereby the fixing means includes a male threaded portion and a female threaded socket portion. Preferably, the male threaded portion forms part of the shaft and the female threaded socket portion is found in the anchor block. The threaded socket may be machined after the attachment means is formed or may be formed by a threaded insert securable to a pre-existing bore in the anchor block.

17. A roof anchor assembly according to any one of the preceding claims in which the shaft is in the form of a bolt, the free end of which is threaded for fixed engagement to the anchor block.

18. A roof anchor assembly according to any one of the claims preceding claims 1

5 16, in which the shaft may includes at its free end spreadable wings adapted for insertion through the second hole thereafter spreadable to engage the underside of the anchor block.

19. A roof anchor assembly according to any one of the preceding claims in which the roof support structure includes a rafter, purlin or any other form of the roof io framework or truss capable of supporting the potentially considerable load which may be placed on the structure in the event of workman falling and relying on the arrangement of the present invention to arrest Ms fall.

20. A roof anchor assembly according to claim 19 in which the structure is a purlin.

21. A roof anchor assembly according to claim 20 in which the purlin has a solid 16 rectangle, C- or channel cross-sectional shape.

22. A roof anchor assembly according to any one of the preceding claims, if the roof anchor is to be mounted onto a roof support structure of considerable thickness, such as may be the case where a solid wooden beam is involved, the shaft will be correspondingly of longer dimension to extend through the structure to its

20 underside surface thereof.

23. A roof anchor assembly according to any one of claims 20 to 22, in which the anchor block is preferably prevented from rotation in a horizontal plane where the roof anchor is to be mounted on, and is achieved by having the anchor block of sufficient length that it is prevented from turning by coming into contact with

25 vertical portions of the purlin, particularly a C-purlin.

24. A roof anchor assembly according to any one of the preceding claims, wherein a weatherproofmg cover in the form of a sealing washer or the like is placed about the shaft to seal the first hole against the ingress of wind and rain, either before or after the mounting of the roof anchor assembly to the support structure.

30 25. A roof anchor assembly according to claim 24 wherein the sealing means is provided about the shaft of the roof anchor to provide a seal about the hole once the roof anchor assembly is fitted.

26. A roof anchor assembly according to claim 25, in which the sealing means is preferably in the form of a sealing washer, the underside of which, has a suitable gasket of compressible material, which may or may not be fixedly attached thereto,

5 27. A roof anchor assembly according to claim 25, wherein the sealing means is in the form of a compressible gasket material which also has adhesive properties to further assist in sealing,

28. A roof anchor assembly according to any one of claims 24 to 27, wherein in the case of roøves having other than flat profiles , such sealing washer is also shaped io to correspond to the profile of the covering material, or be made of sufficiently malleable material so as to be able to be made to conform in situ.

29. A roof anchor assembly according to any one of claims 24 to 28, wherein the sealing between the washer and the shaft of the roof anchor is achieved by means of an O-riπg which is compressed upon fitment of the roof anchor is assembly.

30. A roof anchor assembly according to any one of the preceding claims in which the roof anchor includes any suitable means for attaching a safety harness, rope, harness or like means of securing a workman to the roof support structure to enable to workman to work safely on the roof.

20 31. A roof anchor assembly according to claim 30 in which the attachment means comprise one or more salients to which a rope or cable may be secured, the salient terminating in a bulbous portion to prevent the rope, etc. from working free of the salient.

32. A roof anchor assembly according to claim 30 in which the attachment means 25 comprise a U- or eye bolt to which the safety harness is securely connected.

33. A method for mounting a roof anchor assembly according to any one of the preceding claims on a roof support structure having an underside surface, said roof fully or partially covered with roof covering material, said roof anchor assembly including a roof anchor and attachment means, the attachment means

30 including an anchor block having suspension means to suspend same, said method including the steps of: e) Making a first hole in the covering material and the roof support structure, which first hole is capable of receiving a shaft of the roof anchor; f) Inserting an anchor block, having a second hole capable of fixedly engaging the shaft, through the hole in a first orientation whilst supporting the anchor block with the suspension means; g) Allowing the block to re-orient to a second orientation, once it has been fully inserted, in which it is drawn up against the underside surface utilising the suspension means such that the first and second holes are in registry and the anchor block cannot be withdrawn; and h) Inserting the shaft through both the first and second holes whereby to fixedly engage the roof anchor to the anchor block, such that the roof anchor is mounted on the roof support structure.