AU2328792A - Anchorage device - Google Patents

Description

ANCHORAGE DEVICE

This invention relates to an anchorage device and is particularly, though not exclusively, concerned with an anchorage device for use in anchoring a member such as scaffolding, or a scaffold tower, or a ladder to a structure such as a wall of a building.

Scaffolding and scaffold towers are usually rigidly anchored to buildings for safety reasons by means of drilled- in anchor ties. Such anchor ties comprise a ring having a threaded shank which is screwed into a threaded expansion sleeve inserted into a pre-drilled hole in the wall. Such anchor ties have several disadvantages. First, the ties are relatively expensive and a special punch is required to fit and expand the sleeve in the hole. Second, such anchor ties are not suitable for fixing to all materials, in particular soft stone, for example, Bath stone. Third, such anchor ties require a hole which is relatively large (about 20 mm) which often cannot be satisfactorily repaired once the scaffolding or other member is removed.

GB2125872A and WO91/14061 disclose scaffold anchorage devices each comprising a simple spigot pivotably attached with limited freedom of movement to the scaffold structure, the free end of the spigot being received, in use, inside a borehole in a wall drilled at at least about 15° to a perpendicular to the wall. Several such anchorage devices are used to anchor the scaffolding to the wall the spigot of each device being inserted into upwardly or downwardly extending boreholes. Whilst the scaffold anchorage devices disclosed in GB2125872 and W091/14061 mitigate some of the disadvantages of the anchor ties described above, at least two such anchorage devices are required to provide a secure anchorage and they still require relatively large boreholes to be drilled. Furthermore, whilst providing a safe anchorage when used correctly, it has been found that unskilled operatives may form boreholes which are substantially perpendicular to the wall whereby the inserted spigot has little or no grip on the wall and therefore the anchorage is less reliable.

It is an object of the present invention to provide an anchorage device which overcomes the disadvantages of known anchorage devices, and, in particular, such anchor ties and scaffold anchorage devices.

According to one aspect of the invention there is provided an anchorage device for use in anchoring a member to a structure, the device comprising at least two elongate rigid elements for independent insertion into respective divergent recesses formed in the structure, and holding means for detachably holding the said elements at a position externally of the recesses whereby the rigid elements are anchored in their respective recesses in a divergent state. Thus the anchorage device is fixed by frictional forces acting on the transverse portions of the elongate elements inserted into the structure which may typically be an exterior wall of a building or a floor. The anchorage device in accordance with the invention overcomes the disadvantages of the prior art anchor ties in that it can be manufactured relatively inexpensively and also does not require special tools other than a drill for its use. It can be used in relatively soft stone, and requires only the drilling of relatively narrow diameter holes in the structure.

The anchorage device of the present invention is also advantageous over the scaffold anchorage devices disclosed in GB2125872 and WO91/14061 in that the elongate rigid elements are held in the correct orientation by the holding means.

The said portions of the entire elongate rigid elements may be held together. Alternatively the entire elongate rigid elements may be held together.

The said at least two elongate rigid elements may be joined together. Preferably the rigid elements are flexibly joined together. In a preferred embodiment the elements are joined by a flexible element such as a wire rope.

The holding means may be in the form of a clamp. The clamps may clamp together portions of the rigid elements.

The, or each, portion may be transverse to the remainder of the element when inserted into the structure. The or each transverse portion of the device may extend at 20 to 70°, preferably about 45° to the longitudinal axis of the device. The said portion(s) may be integral with the remainder of the element(s) .

The anchorage device may comprise three or more such elongate rigid elements.

Preferably, the transverse recesses may be in the form of holes drilled into the structure. According to another aspect of the invention there is provided an insert for insertion into a structure for use with an anchorage device, the insert comprising at least one transverse recess for receiving the elongate rigid element or a portion thereof of the anchorage device.

Anchorage devices in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings Figures 1 to 6 in which:

Figure 1 is a plan view of a anchorage device in accordance with the invention in a disassembled state;

Figure 2 is a partial section through a wall showing the anchorage device of Figure 1 in use;

Figure 3 is a plan view of another anchorage device in accordance with the invention in a disassembled state; Figure 4 is a partial section through another wall showing the anchorage device of Figure 3 in use;

Figure 5 is a plan view of a further anchorage device in accordance with the insertion in an assembled state; and Figure 6 is a plan view of a preferred anchorage device in accordance with the invention in a partially disassembled state.

The anchorage device 10 shown in Figures 1 and 2, comprises two lengths of steel bar 12 and 14, (the "elongate rigid elements"), which are swaged onto either end of a length of flexible steel rope 16. The lengths of steel bar 12,14, can be fixed to the length of steel wire 16 by other methods, for example, welding or gluing. The anchorage device 10 also includes a steel clamp 18 (the aforesaid "means") which comprises a U-shaped member 20 having threaded shanks 22,24, which receive correspondingly-threaded nuts 26,28. The nuts 26,28, retain a drilled plate 30 on the shanks 22,24. In use, and as shown in Figure 2, relatively narrow diameter holes

32.34, are drilled into the surface 36 of wall 38 at an angle of preferably between 20 to 40 degrees to axis 39 normal to the surface 36.

The lengths of steel bar 12,14, are inserted into the holes 32 and 34 respectively, as shown in Figure 2, and the clamp 18 is placed about the lengths of steel bar 12,14, to clamp them transverse to each other at an angle corresponding to the angle between holes 32,34 when nuts 26,28 are tightened. The steel wire 16 forms a loop 40. Movement of the anchorage device 10 in the direction of arrow A of Figure 2, that is to say away from the wall 38, is prevented by the frictional forces between the transverse steel bars 12,14, and the walls

33.35, of the holes 32,34, whilst the lengths of steel bar 12,14, are rigidly held in a mutually transverse position by clamp 18. The loop 40 formed by the steel wire may be conveniently formed about the member to be held to the wall 38, for example, a scaffold pole (not shown). Alternatively, conventional fixing means, for example, a shackle, may be used to hold the member to the loop 40. The anchorage device 70 can be removed from the wall 38 by removing clamp 18 and withdrawing lengths of bar 12,14.

The anchorage device 50 shown in Figures 3 and 4, comprises relatively long, and relatively short length of steel bar, 52 and 54 respectively, to which are swaged relatively short and relatively long lengths of steel wire, 56,58, respectively. The lengths of steel bar 52,54, are welded together but might be formed integrally, for example, by casting. To the free ends of lengths of steel wire 56,58, are swaged, or otherwise fixed, further lengths of steel bar 60,62, respectively. A collar of steel tube 64 is free to slide along steel wire 58.

The anchorage device 50 further comprises a clamp 66 which is similar to clamp 18 shown in Figures 1 and 2 and described earlier save for a cast piece 68, which takes the place of plate 30 in clamp 18, and which is shaped to fit to the steel bar 52 and collar 64.

In use, and as shown in Figure 4, holes 70 and 72 are formed in wall 74 at an angle of about 20 to 40 degrees to an axis 76 normal to surface- 78 of wall 74. The length of steel bar 60 and 62 are inserted into the holes 70 and 72 as shown, the longer length of steel wire 58 facilitating the insertion of length 62 into hole 72. The clamp 66 is then placed about the end of steel bar 52 adjacent steel wire 56 and the sliding steel collar 64 to clamp rigidly the collar 64 to steel bar 52. In this position, the anchorage device 50 is fixed to the wall 74 by virtue of the frictional forces described above in relation to the Figure 1 and Figure 2 embodiment. However, the anchorage device 50 can be readily removed from wall 74 by removal of the clamp 66 followed by removal of the respective lengths of steel bar 60,62, from the holes 70,72. Members, such as ladders or scaffold to be fixed to wall 74, may be fixed to the anchorage device 50 by conventional means. The flexibility conferred upon the device by the lengths of steel wire 56,58, allows the fastening device to be used even when the angle of drilling of holes 70,72, is not particularly accurate.

Where accurate drilling of holes in a structure is possible, the anchorage device may comprise at least two lengths of rigid bar or tube as shown in Figure 5. The anchorage device 80 shown in Figure 5 comprises two lengths of steel bar 82,84, which are bent at an angle of 30 degrees to their respective longitudinal axis. The lengths of bar 82,84, can be held together by means of clamp 86, which is similar in operation to clamps 18 and 66 already described, after insertion of their respective ends into corresponding accurately angled holes formed in a structure.

The anchorage device 90 shown in Figure 6 which is in accordance with a preferred embodiment of the invention comprises two bent lengths of steel bar 92 and 94 which are swaged onto either end of a length of flexible steel rope 96. Transversely-extending portions 93,95, of the bars 92,94, extend at about 35° to the longitudinal axis of the anchorage device 90 in use. A length of steel rope 96 passes through steel tubes 98 and 100 which are welded to steel plate 102. Plate 102 defines guide holes 104 and 106. A steel ring 108 is also welded onto plate 102. The ring 108 is sufficiently wide in internal diameter so as to allow a scaffold pole to pass therethrough.

A clamp 110, comprising upper and lower clamp elements 112 and 114 respectively, is arranged to clamp parallel portions 116 and 118 of steel bars 92 and 94 respectively. Lower clamp element 114 includes a threaded element 120 which is arranged to extend through aperture 122 defined by upper clamp element 112. In use a nut and spring washers (not shown) screw onto the end of the threaded element 120 protruding through aperture 122 to clamp elements 112 and 114 together about portions 116 and 118 of steel bars 92 and 94. A spacing element in the form of a boss 121 welded onto the lower clamp element 114 keeps the portions 116 and 118 apart as they are clamped by the clamp 110. Alternatively, a portion of the upper or lower clamp element 112,114, may be deformed to provide a similar spacing element. In order to use the anchorage device 90 to anchor a scaffold pole to a wall the plate 102 is held up against the wall and the wall is marked through guideholes 104,106. A hole is drilled into the wall at each marking at an angle of about 35° using either transverse portion 93,95 as a guide.

The transverse portions 93,95 are then inserted into the drilled holes leaving the portions 116 and 118 of the bars protruding therefrom. The clamp elements 112 and 114 are then clamped about the ends 116 and 118 of the steel bars 92,94, as described above. A scaffold pole can then be inserted into the ring 108 inside loop 124 formed by steel rope 96.

It is contemplated that the transverse portions of fastening devices in accordance with the invention may be made relatively thin so as to allow use with less substantial structures than walls and ceilings.

It is anticipated that holes for inserting fastening devices in accordance with the invention maybe provided in new structures by a recessed body forming the holes inserted in the structure during construction. For example, the recessed body may be formed of a plastics material and inserted in the structure, for example, the wall of a house during the construction of the house whereby the holes defined by the recesses of the body are open for insertion of a fastening device of the invention. Alternatively, and in a preferred embodiment, the body may be inserted in a cast concrete floor during construction. Such an embodiment may be particularly useful for supporting pipework associated with the floor.

The internal surfaces of the holes defined by the body may be textured, preferably ribbed, to provide a key for a resin injection about the fastening device after insertion of the rigid elements into the holes to fix the fastening device in place.

Claims (13)

CT.ATMS

1. An anchorage device for use in anchoring a member to a structure, the device comprising at least two elongate rigid elements for independent insertion into respective divergent recesses formed in the structure, and holding means for detachably holding the said elements at a position externally of the recesses whereby the rigid elements are anchored in their respective recesses in a divergent state.

2. An anchorage device according to claim 1, in which the recesses diverge from a substantially common point.

3. An anchorage device according to claim 1 or 2. in which the or each element is formed to have a transversely extending portio .

4. An anchorage device according to claim 3, in which the or each transversely-extending portion is/are inserted into the structure.

5. An anchorage device according to any preceding claim, in which the elements are joined together.

6. An anchorage device according to claim 5, in which the elements are flexibly joined together.

7. An anchorage device according to any preceding claim, in which the holding means is in the form of a clamp.

8. An anchorage device according to claim 7, in which the holding means is arranged to clamp together the elongate rigid elements.

9. An anchorage device according to claim 8, in which the holding means is arranged to clamp together parallel portions of first and second elongate rigid elements.

10. An anchorage device according to any one of claims 1 to 9, in which each parallel portion is integral with a transversely-extending portion.

11. An anchorage device according to any one of claims 3 to 10, in which at least one transversely-extending portion extends at 20 to 70° to the longitudinal axis of the device.

12. An anchorage device according to any preceding claim adapted to engage a scaffold member.

13. An insert for insertion into a structure for use with an anchorage device, the insert comprising at least one transverse recess for receiving the elongate rigid element or a portion thereof of the anchorage device.