GB2254367A - Scaffold fitting for attaching to walls etc. - Google Patents

Abstract

A scaffold fitting has a generally channel-shaped body part (12) providing a seat (17) for a scaffold tie tube (10), the body part having a large base (19), with a flat exterior surface (21), and generally convergent sides (18). In one embodiment a domed or arch-shaped washer (22) is fitted over an interior surface (20) of the base between its sides (18), the washer having a hole (25) therethrough in alignment with an aperture (26) in the base (19). This body can be used to provide a complete scaffold fitting in conjunction with expansion anchor means which extend through the washer hole (25) and aperture (26) to the outside of the body part, where a screw thread is provided to draw an expansion member (33, 38) along the thread and secure the anchor, in use, in a hole (36). In Figures 1 to 3 the expansion member (33) is a reusable rubber sleeve. In another embodiment the expansion member (38) is conical and causes a surrounding sleeve to splay out. Instead of a domed washer, the base itself can be domed inwardly around the aperture (26). <IMAGE>

Description

SCAFFOLD FITTING This invention relates to a scaffold fitting, particularly for anchoring a scaffold tie tube to a face of a structure, such as a building.

There are many proprietary fittings for connecting a scaffold tie tube to a structure. The tie tube is often fixed normal to a surface of a structure and with one form of proprietary fitting a bolt thereof is connected to a separately fixed anchor in the surface.

The fitting resists axial loads in the tie tube, but generally any lateral forces on the tie tube are not resisted by the fitting, with the resultant bending of the anchoring bolt, an acknowledged weakness of such fittings. The same bending of the bolt occurs as a result of loads from tubes which, being inclined to the structure, impose substantial loads parallel to the face of the structure.

The commonest scaffold tie fittings have a captive bolt and recent tests have shown that these fittings have little lateral strength due to the bending of the bolt.

The most commonly used ring bolt tie has a long shank which will bend if the tie is subjected to quite small lateral loading. Indeed manufacturers advise against application of any lateral loads. A further disadvantage of this ring bolt fitting is that a scaffold tube is able to slide through and rotate in the forged ring.

Such ring bolts and the tie fittings with bolts attached usually require a socket anchor flush with or just below the face of the structure. These are normally used once only and remain in the structure thereafter as they cannot be removed. The threaded socket in the face of the structure is normally of steel which may rust if not effectively sealed, spoiling the appearance of the face.

A socket anchor commonly used as a drilled fixing is in the form of an internally threaded metal anchor tube with the internal end split and a built-in expansion cone. This anchor requires the use of the correct diameter and length setting punch hammered into the anchor tube against the cone in order to produce the correct expansion of the split inner end of the tube by means of the cone. The strength and safety of the anchor, and ultimately of the scaffold using a fitting incorporating the anchor, relies on the workmanship of the operative to drill an accurate hole, insert the anchor and expand it correctly with the punch. This operation is open to misuse on site.

The need for this problem of handling lateral forces to be overcome has been highlighted in the U.K. in particular by scaffold failures during gales in recent years and Regulations severly restricting the size of sheeted scaffold structures.

An object of the invention is to provide a complete scaffolding fitting which overcomes or at least alleviates this problem and provides a rigid connection, in use, of a tie tube to a structure, and also to provide a scaffolding fitting part for use with different expansion anchor means.

According to one aspect of the invention a scaffold fitting comprises a base part having a flat or substantially flat exterior surface with an aperture therein, a force transmitting member extending normally or substantially normally from said exterior surface to terminate at an end spaced therefrom, part of said member being within said aperture, thread means being provided beyond said end of the member, and at least part of expansion anchor means being on said thread means.

According to another aspect of the invention there is provided a scaffolding fitting part for use with expansion anchor means to form a scaffold fitting, the part being in the form of a body of generally channelshape in transverse cross-section having a base which has a generally flat external surface, respective sides extending away from an internal surface of the base, said sides having respective mutually convergent portions, there being between said sides a surface which is raised relative to said internal surface or to a remainder thereof, and an aperture through said raised surface only or respective apertures through said raised surface and said base for engagement of said body with said expansion anchor means.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of part of a scaffold fitting of the invention, with a scaffold tie tube being shown secured thereto; Figure 2 is a part-sectional end view of the whole of the fitting of Figure 1; Figure 3 is a part-sectional side view of the fitting of Figure 2, with an anchor sleeve thereof expanded to fix it in a bore in a surface to which the fitting is thus secured; Figure 4 is a part-sectional end view of part of another embodiment of a scaffold fitting of the invention secured to a surface and showing a scaffold tie tube; and Figure 5 is a view like Figure 4, but showing part of a further embodiment of a fitting of the invention.

Figures 1 to 3 show a scaffold fitting according to a first embodiment of the invention for securing a scaffold tie tube 10 parallel to a flat or generally flat surface 11 of a wall of a building or the like.

The fitting has a body part 12 and a cover part 13 mounted thereon by a pivot 14 at one end of the body part. The other end thereof has a threaded bolt 15 and nut 16 for securing the cover part 13 tightly down onto the tube 10 when the tube is on a seat 17 formed on opposite sides of the body part. As so far described, the fitting is like a conventional scaffold clamp.

However the body part 12 of the fitting of the invention is formed with upwardly converging or splayed sides 18 so that the base 19 of the fitting is effectively enlarged as compared to conventional scaffold clamps, the base defining flat upper, inner and lower, exterior surfaces 20, 21 respectively. The parts 12 and 13 are both preferably steel pressings, steel forgings or aluminium castings. The splaying of the sides provides increased strength, acting as a strut and a tie to transmit lateral loads to the structure. This splaying can be directly from the base, at the extremity of each side, or somewhere between the base and the free ends of the sides as shown.

Secured on the surface 20 of the base is an arched or domed mild steel washer 22 providing a raised surface 23 relative to said flat surface 20. The doming can be greater or smaller than that shown, as required. The washer could be secured by resin glue 24, as shown, but is preferably pressed into position between the sides 18, so that thereafter its ends spring out to hold it secure.

The washer preferably extends across the whole width of the base and for at least some, but not necessarily all of its length, and can be open or closed at its ends. A circular hole 25 extends normally through the washer and this is aligned with a co-axial circular aperture 26 through the base.Passing through the aperture 26 is a force or load transmitting member 27.A set screw 28 has a threaded shank 29 and a head 30,the shank 29 passing through washer hole 25 and engaging with an internally threaded boss part 31 of the member 27.The head bears on surface 23 of washer 22 as shown.

The hole is oversized for shank 29 so that with the 'normal duty' fitting described and illustrated the set screw 28 can rock angularly relative to washer 22.The hole 25 and aperture 26 could instead provide tight passage for shank 29 and boss part 31 if relative adjustment of the body part to the anchor is unnecessary.

With this 'normal duty' fitting, it may be possible to dispense with the washer 22 and provide its effect merely by slightly inwardly doming or raising the base around aperture 26. This can increase the stiffness of the base sufficiently. A loose or secured plain washer can be provided over the aperture in the domed base part. The provision of the washer 22 is more necessary with a 'heavy duty' version of the fitting, to be described with reference to Figure 4. In this version the hole 25 is again oversized, as described. To transmit shear, especially from reversing loads, the anchor sleeve also needs to fit fairly well into the hole 26 in the base (not a machine tight fit). Angular inaccuracies will be accommodated by the large hole 25 allowing a bolt to move, as will be described. The bolt is tightened by a socket torque spanner with the fitting cap open.

With the 'normal duty' version of the fitting, it may be possible for the fitting to be tightened, loosened, removed and reused with the stub tube 10 still in place. The head 30 of the set screw could be prevented from rotating by a suitable tab washer.

The invention envisages that a suitable body of a fitting could be supplied to a site, for the eventual use with a selected anchor depending on the application required, e.g. brick, concrete, wide cavities between brick skin and concrete structure, etc. The two bodies described, with or without the washer 22, but both inwardly domed between their respective pair of sides, and with or without oversized holes, represent only two embodiments of the aspect of the invention relating to a fitting body part.

The height of the body is preferably made a minimum to reduce the lever arm of the lateral force. As described, the shank 29 engages with boss part 31 of the member 27, the part 31 being integral with or nonrotatably connected to the remainder of the member 27 in the form of a concentric, externally threaded, smaller diameter bolt 32, the screw thread extending inwards from its free end for part of its length. The set screw should be of the correct length to 'bottom' on the base of the boss part 31 so that continued turning of screw head 30 rotates bolt 32, but without tightening part 31 against underside of washer 22.

To accommodate tolerances due to a circular section hole 36 drilled in surface 11 to receive the anchor not being at 900 thereto, the hole 25 is oversized as described to allow the set screw to carry out rocking movement relative to washer 22, or equivalent domed surface of the base. The boss part 31 is however preferably a snug fit in aperture 26 to take shear loads and transmit lateral loads from the fitting body to the structure having surface 11. The boss could, for example rock by about 10 . One or both of hole 25 and aperture 26 could be tapered to facilitate the rocking movement mentioned. By providing for this adjustment the anchor can extend normally from the base, or 'substantially normally' which includes an angle of at least approximately 10 .

Fitted on the bolt is an expansion anchor in the form of a sleeve 33 of rubber, such as chloroprene or neoprene, which is spaced radially outwardly of the bolt thread. The sleeve has a metallic insert sleeve 34 fitted in its outer end, this insert providing an internal screw thread which is complementary with the thread on the bolt 32. Preferably a short metallic locator sleeve 35, which is not internally threaded, is fitted in the other end of the sleeve 33, spaced from the termination of the bolt thread. The anchor used in this example is one developed by Hilti and denoted by them as a Hilti Temporary Anchor (HTA).

Accordingly, in use, the sleeve 33 can initially be engaged on the bolt 32 as a push fit at its end where the sleeve 35 is fitted, the thread of sleeve 34 thereafter engaging on the thread of bolt 32, so that the sleeve 34 can be screwed up on the bolt until the sleeve 35 abuts against the underside of the boss part 31, as shown in Figure 2. The fitting, normally as yet without the tube 10 engaged with it, is now ready for fastening into circular section hole 36 preferably drilled at 90" into the surface 11 of a structure shown in Figure 3, the hole being of a diameter to allow insertion of the boss 31 as a close fit.

Accordingly, in use, the boss, sleeves and bolt are placed in the hole 36 with the flat exterior surface 21 of the base 19 engaging against or close to the surface 11. The set screw 28, and thus the boss part 31 and bolt 32, is then rotated and due to engagement of the outside surface of the sleeve 33 with the side of the hole, this causes the part of the sleeve inward of sleeve 34, and preferably the part between the metallic sleeves, to move axially relative thereto, with the effect that, since the upper end of the sleeve is firm against boss part 31, the sleeve is compressed and expands radially outwardly, as shown in Figure 3, so as to fix the anchor tightly in the hole 36.The compression of the sleeve additionally pulls the base of the fitting tightly onto the surface 11. The boss 31 is in contact with the inner surface of the hole 36 thereby to transfer into the wall lateral tensile or compression loads, or loads alternating between the two, from the tube 10 or from inclined tie tubes 10a fixed to the tube 10 with right angled couplers (not shown). The rotation of the set screw is carried out before a tube 10 is fitted to it.

If there is a possibility that the sleeve 33 will rotate fast with the bolt 32 upon initial rotation of the set screw, due to a slightly oversized hole, some preliminary manual expansion of the sleeve on the bolt to begin expansion will allow the sleeve then to be placed sufficiently tightly in the hole for expansion upon rotation of the set screw 28.

To remove the fastener from the wall, it is merely necessary to turn the head 30 in the opposite direction, thus reducing the expanded diameter of the sleeve 33 so that the boss part, bolt and sleeve can all be withdrawn from the hole 36. The whole fitting can be unfixed from the wall as a unit with no loose parts and can be re-used without any special tools. In practice it is envisaged that head 30 will fit a scaffolder's key.

The provision of the washer 22 removes the load in the anchor bolt from the centre of the flat base 19.

'Vertical' loads now pass into the domed washer, which, compared to the base 19, is very stiff in the 'vertical' direction. The set screw through the washer passes the 'vertical' load, which is essentially a tensile load, to the remainder of the anchor which is fixed, in use, in a structure. The washer resists large 'vertical' forces without excessive deformation in order to avoid loading the large base 19 producing deformation thereof.

Horizontal or lateral loads from tube 10 still pass from the sides of the fitting into the base, from where they are transmitted into the boss part and/or sleeve to be resisted by the structure into which the boss part 31 has been fitted to which the anchor is fixed.

Instead of the optional use of a resin glue to fix the washer 22 in place, it could be welded or brazed in place at its ends, which function like the springing of an arch causing bending in the assembly and still enable a double coupler to be fixed to the stub tube.

The large base, which is in intimate contact with the surface 11 the structure, cannot slide due to the boss part 31 in the hole 36. The body 12 tends to rock about part 31, this action causing one end, the compression end, of the flat base surface to tend to dig into the surface 11 and the other end, the tension end, to try to lift off surface 11. This lifting action is resisted by the tension thus induced in the anchor bolt for both the normal and heavy duty fittings. With the heavy duty version, the pre-tensioning of the anchor bolt pulls the whole of the base hard down on to the surface 11. This pre-tensioning of the assembly results in considerably more lateral load being resisted by the assembly before any noticable lifting of the tension end of the base occurs.The assembly is also able to resist reversing loads in the tube 10 such as occur when tying in the mast of a hoist.

The base thus converts lateral force into a tension in the anchor bolt, which it is able to absorb, and a compression onto the structure's face. The engagement of the boss part, or the equivalent sleeve to be described with the 'heavy duty' fitting, transmits shear forces into the structure.

The fitting overcomes the disadvantages of many of the above mentioned known scaffold fittings or the like for use with tie tubes and provides several advantages.

Firstly, as expressed in detail above, the boss at the base of the scaffold fitting bears, in use, against the side of the anchor hole in the wall, to transfer lateral loads from the scaffolding fitting to the structure. At normal working loads the lateral vector of the load in the tie tube(s) parallel to the face of the wall is converted by the fitting into tension in the anchor bolt by the boss, as mentioned, bearing on the side of the anchor hole, and the base of the fitting bearing against the face of the structure.

To anchor higher loads from the scaffold, e.g.

loads caused by a sheeted scaffold or a goods or passenger hoist, two scaffold tie tubes are connected to the tube in the filling with right-angled couplers. This arrangement causes the longer longitudinal axis of the base of the fitting to bear against the face of the structure, thus improving the geometry of the fitting.

Secondly compared to known proprietary fittings for tying scaffolds, the fitting of the invention has good resistance to lateral loads and the combination of reactions of the bolt, boss and base of the fitting eliminates most if not all bending in the bolt. The scaffold tube can, moveover, no longer rotate or slide relative to the fitting, under normal loads, which is not the case with ring bolt ties.

Thirdly compared to the scaffold tie fittings referred to, the fitting of the invention ensures that tightening of the anchor beings the large base into intimate contact with the face of the structure. Lateral forces on the tube produce compression under the front of the base and tension in the bolt, which it is designed to resist, together with a shear force parallel to the face of the structure which the boss on the underside of the fitting transmits into the structure.

Fourthly, with regard to the Hilti HTA anchor, this is completely removed with the remainder of the fitting, after use, allowing the face of the structure to be successfully repaired. Removal of the anchor, namely the rubber sleeve, occurs automatically as the fitting or set screw/bolt is counter-rotated and pulled out of the hole drilled in the structure. The sleeve remains on the bolt and can be reused several times with no need to dismantle the assembly between uses, which is labour saving. As compared to socket anchors described above, the use of a rubber sleeve as part, with the bolt, of a reusable anchor, makes the diameter of the hole less critical, and the tightening torque required has a greater tolerance compared with some commercially available anchors.As the anchor is on the fitting when it is inserted into the hole, the depth of the hole is not important as long as the anchor can be inserted until the base 19 of the fitting bears against the face 11 in which the anchor hole 36 is drilled.

For the embodiment of the invention shown in Figures 1 to 3, the anchor will be set by tightening the set screw head 30 with a scaffolder's key. However if the hole is accurately drilled and, as described, the screw 28 is held, and the whole fitting is rotated, the use of tools is not necessary, as the anchor is expanded and tightened by the scaffolder rotating the fitting whilst keeping the base thereof in contact with the wall of the structure. This is an easy operation which can be inspected, the rotation being continued for the number of turns recommend by the anchor manufacturer or until the anchor feels sufficiently tight. The scaffold then adjusts the aspect of the fitting so the stub tube held thereby is at the required orientation for the connection of the scaffold tie tubes.The rubber sleeve of the anchor will accept a little further tightening of the fitting, if required, at this stage of the fixing process, without appreciable overstress of the anchor.

Where the hole 36 is at 900 to surface 11, the stub tube can also remain in the fitting and anchor unit, thereby saving labour, and can be used as a handle when tightening the anchor. Removal of the assembly is by counter-rotating the filling. There are no loose parts to be mislaid, or more importantly, to become detached and fall to the ground, so that the safety aspect is enhanced.

Figure 4 shows the above mentioned 'heavy duty' embodiment of the invention, the fitting differing from that of Figures 1 to 3 in the nature of the expansion anchor. With the Figure 4 embodiment, the fitting employs a heavy duty split expansion sleeve 37 and a conical expansion member 38. The anchor shown and described is a Hilti HSL anchor, but any suitable alternative anchor of Hilti or another manufacturer could be used.

The body of the fitting is the same as with the first embodiment, having washer 22 with hole 25 therein aligned with aperture 26 in base 19. In this embodiment, the circular hole 25 through the washer is concentric with aperture 26, but is of smaller diameter. A bolt 39 has a head 40, which is larger than the diameter of hole 25 and which, via a flat washer, bears against the inner surface 23 of domed washer 22, and a screw-threaded stem 41 which extends through hole 25 and aperture 26, and out of the base of the fitting. The hole 25 is preferably oversized to accommodate relative angular adjustment movement between the body and the anchor bolt 39.

Around the bolt stem is a thick walled cylindrical tube 42 having its one end received as a relatively snug fit in aperture 26 to transmit lateral loads from body base 19 to tube 42. However it can also be loose enough in aperture 26 to accommodate angular movement. The inner end of tube 42 abuts the underside of washer 22.

The tube is a close, sliding fit on the bolt stem to enable it thus to slid along from the free end of the bolt-stem once the bolt has been engaged with the fitting base, as described.

Fitted on the end of the tube remote from its abutment against the washer 22 is a plastics material collar 43, its end which is spaced from the tube being configurated so as to engage with the narrower, inner end of said split, expansion shell or sleeve 37 and prevent relative rotation. The stem of the bolt extends through both the collar 43 and sleeve 37, and said expansion member 38, in the form of a frusto-conical plug, is engaged on said stem 41 thread by means of a complementary internal thread.

In use, the bolt 39, tube 42, collar 43, sleeve 37 and plug 38 are engaged together on the fitting which is then placed into a hole 36 in a concrete or other structure. In this embodiment there is a need for the bolt to be tightened and this can be accurately with a torque spanner. This tightening causes the member 38 to be drawn inwardly of the sleeve 37 on the bolt stem, as the bolt is rotated. This movement causes a splaying of the split sleeve 37, such expansion thereof securely engaging the outwardly extended 'arms' of the sleeve with the side of the hole 36 and fixing the anchor in place with the exterior surface 21 of the base 19 held against the surface of the structure in which the hole is drilled. Tightening takes place with the fitting cover open and before a stub tube is engaged on the fitting seat.Tightening the anchor bolt 39 with a torque spanner further pulls and tightens base 19 onto the surface 11, thus enhancing the rigidity of the assembly, in use, and improving its load bearing charcteristics, especially with respect to lateral loads.

The tube 42 acts a force, in this case shear, transmitting member. The pulling of the fitting tight on to the structure as the bolt is tightened enhances its resistance to lateral loads. Such loads are transmitted to the structure by the fitting bearing against the side of the tube 42, with the tube itself bearing against the side of the anchor hole 36 in the structure. The top of tube 42 is brought into intimate contact with the underside of washer 22.

Withdrawal of the anchor fitting is carried out by untightening the bolt 39, allowing removal of the bolt 39 and tube 42 from the anchor hole. The collar 43, expanded sleeve 37 and expansion member 38 are left well inside the structure, allowing the hole 36 to be made good, eliminating the risk of corrosion from the steel parts 37 and 38.

The further embodiment of the invention shown in Figure 5 relates to a fitting suitable for use with thin walled scaffold tube. Instead of the tube being engaged at its respective opposite seats of the fitting on edges, as per Figure 4, Figure 5 shows a thin walled tube 44 with the seat surface 17 of the body machined to fit the tube so that under load it is not damaged by bearing on an edge. Additionally the hinged cap 45 of the fitting may be of forged steel to provide, a shown, a large surface in contact with the tube 44. The anchor arrangement is shown as with the first described embodiment, but other anchor details, such as that of Figure 4 are equally suitable.

In a further embodiment, the 'heavy duty' version of the fitting could have the washer 22 connected to the tube 42. In the case where the washer is omitted and the base merely inwardly domed, the tube could have an integral end flange secured within the body to the domed base around the aperture 26.

The commercial advantages of a fitting of the invention are considered to be: a) A saving in the cost of materials with the normal duty version. Although the initial cost of the version of the new fitting including the reusable rubber sleeve may be more than some of the alternatives, consideration by a user of the cost of providing several non-reusable anchors will show that in the long term the new fitting with a reusable anchor is more economic. As there are no loose parts, the safety on site is enhanced also a commercial consideration.

b) The labour cost and the programme time of fixing the new fitting with its reusable anchor, which is removed and ref fixed as a single unit, is less than fixing separate anchors and tie fittings.

c) For some embodiments of the new fittings special tools are not essential for establishing the anchor in place, for example a punch and hammer. Apart from a torque spanner as described for the heavy duty version, the scaffold need not be provided with nor need carry such tools, as his scaffold key will fit the anchor bolt.

A fitting of the invention is particularly advantageous as compared to a conventional ring bolt tie when considering meeting British Standards. In particular the fitting would meet or assist Designers with specialist experience to meet the requirements of the latest Regulations relating to temporary buildings, including scaffolding, where wind induced vibrations and deflections need to be taken into consideration.

Claims (31)

1. A scaffold fitting comprising a base having a flat or substantially flat exterior surface with an aperture therein, a force transmitting member extending from said exterior surface to terminate at an end spaced therefrom, part of said member being within said aperture, thread means being provided beyond said end of the member, and at least part of expansion anchor means being on said thread means.

2. A fitting as claimed in Claim 1, wherein the force transmitting member extends normally or substantially normally from the exterior surface of the base.

3. A fitting as claimed in Claim 1 or Claim 2, having a body which is of generally channel-shape in transverse cross-section having respective sides extending away from one side of the base, said sides having respective mutually convergent portions.

4. A fitting as claimed in Claim 3, wherein each of said mutually convergent portions is at a position spaced from said base and also from a free end of its side.

5. A fitting as claimed in any one of Claims 1 to 4, wherein between said sides is a surface raised relative to an interior surface of said base or to the remainder of said interior surface of said base, said raised surface being over said aperture or having it therein respectively.

6. A fitting as claimed in Claim 5, wherein the raised surface is provided by a domed washer fast between said sides and having a hole therethrough aligned with said aperture in said base.

7. A fitting as claimed in Claim 6, wherein a shank of a headed screw extends through said hole, the shank threadedly engaging a boss extending through said aperture.

8. A fitting as claimed in Claim 5, wherein the raised surface is provided by a part of said interior surface of said base which is domed inwardly relative to the remainder thereof, said part having said aperture therein.

9. A fitting as claimed in Claim 8, wherein a shank of a headed screw extends through said aperture, the shank threadedly engaging a boss extending through said aperture and around said shank.

10. A fitting as claimed in Claim 7 or Claim 9, wherein a bolt extends non-rotatably from the boss, the bolt terminating at a free end from which a screw-thread extends along the bolt towards said boss.

11. A fitting as claimed in Claim 10, wherein the expansion anchor means is a sleeve which is internally screw-threaded complementarily to the screw-thread on the bolt so that it can be screwed thereon until its leading end abuts the boss, further relative rotation in one direction between the sleeve and the bolt causing compression of the sleeve with consequent outward expansion thereof.

12. A fitting as claimed in Claim 5, wherein said expansion anchor means comprises an internally threaded expansion member engaged on said thread means and having a frusto-conical outer surface, the expansion member being received within a split expansion sleeve, so that in use movement of the expansion member along said thread means in one direction causes a splaying out of the expansion sleeve.

13. A fitting as claimed in Claim 12, wherein the raised surface is provided by a domed washer fast between said sides and having a hole therethrough aligned with said aperture in said base.

14. A fitting as claimed in Claim 13, wherein the thread means are on a headed bolt extending through said hole in said domed washer and also through a tube constituting said force transmitting member, an end of said tube being received, in use, in said aperture.

15. A fitting as claimed in Claim 12, wherein the raised surface is provided by a part of said interior surface of said base which is domed inwardly relative to the remainder thereof, said part having said aperture therein.

16. A fitting as claimed in Claim 15, wherein the thread means are on a headed bolt extending through said aperture and through a tube constituting said force transmitting member, and of which is received, in use, in said aperture, around said bolt.

17. A fitting as claimed in Claim 14 or Claim 16, wherein there is a collar between said force transmitting tube and said expansion sleeve which prevents relative rotation therebetween.

18. A fitting as claimed in Claim 14, wherein said head of the bolt directly, or indirectly via a plain washer, and said end of the force transmitting tube engage, in use, against respective opposite sides of said domed washer.

19. A fitting as claimed in Claim 14, wherein said domed washer is secured to the force transmitting tube at said end of said tube.

20. A fitting as claimed in Claim 3, wherein said sides define respective seats for a scaffold tube to be retained by the fitting, each seat comprising a bearing surface having an extent parallel to the length of the tube when retained.

21. A fitting as claimed in any one of the preceding claims, comprising a pivoted, releasably securable cover for engagement on to a scaffolding tube to retain it with the fitting, the cover having a bearing surface which across the whole of its extent in the longitudinal direction of the tube engages said tuber in use.

22. A fitting as claimed in Claim 7 or Claim 9, wherein said headed screw is prevented from rotating relative to said base.

23. A method of securing to a surface a scaffolding fitting as claimed in any one of the preceding claims, comprising the steps of providing an aperture in said surface, inserting said expansion anchor means and the part of said force transmitting means extending from said exterior surface of the base into said aperture so that said base exterior surface contacts or is in juxtaposition with said surface, and rotating said thread means thereby to cause expansion in said aperture of an expandable part of said expansion anchor means and tightly secure the fitting to the surface.

24. A method as claimed in Claim 23, wherein rotation of the thread means is produced by rotating the fitting.

25. A method as claimed in Claim 23, wherein rotation of the thread means is produced by rotation of a head of a bolt or screw providing said thread means.

26. A scaffolding fitting part for use with expansion anchor means to form a scaffold fitting, the part being in the form of a body of generally channel-shape in transverse cross-section having a base which has a generally flat external surface, respective sides extending away from an internal surface of the base, said sides having respective mutually convergent portions, there being between said sides a surface which is raised relative to said internal surface or to a remainder thereof, and an aperture through said raised surface only or respective apertures through said raised surface and said base for engagement of said body with said expansion anchor means.

27. A scaffolding fitting part as claimed in Claim 26, wherein said raised surface is provided on a domed washer fitted in the body.

28. A scaffolding fitting part as claimed in Claim 26, wherein said raised surface is provided on a domed part of the body itself.

29. A scaffolding fitting substantially as hereinbefore described, with reference to, and as shown in Figures 1 to 3, or Figure 4, of the accompanying drawings.

30. A method of securing to a surface a scaffolding fitting substantially as hereinbefore described, with reference to, and as shown in Figures 1 to 3, or Figure 4, of the accompanying drawings.

31. A scaffolding fitting part substantially as hereinbefore described, with reference to, and as shown in the accompanying drawings.