GB2090360A

GB2090360A - Eyebolt anchors

Info

Publication number: GB2090360A
Application number: GB8035344A
Authority: GB
Original assignee: PHILLIPS DRILL CO UK Ltd
Current assignee: PHILLIPS DRILL CO UK Ltd
Priority date: 1980-12-30
Filing date: 1980-12-30
Publication date: 1982-07-07

Abstract

An eyebolt anchor comprises a bolt 1 which carries a resilient sleeve 4, and rigid sleeve 6 and an eye-ring 7 which is threaded on the end 2 of the bolt. The anchor is inserted into a hole 10 in wall 11 and the eye-ring is screwed up against the rigid sleeve to compress and expand the resilient sleeve 4. When the anchor is no longer required the eye-ring is unscrewed to remove the compressive pressure on the resilient sleeve and the anchor can then be withdrawn from the hole. In a modification, a nut may be threaded on the bolt between the eye-ring and rigid sleeve. <IMAGE>

Description

SPECIFICATION Eyebolt anchors This invention relates to eyebolt anchors and is particularly useful for providing secure yet temporary anchorages for scaffolding and personnel working on high buildings.

Recent legislation requires that in certain circumstances scaffolding must be anchored to the building against which it is erected. However, once the scaffolding is removed it may be desirable to remove any temporary fixings to render the finished building aesthetically acceptable.

The law also required personnel working on the outside of high buildings, e.g. steeplejacks and maintenance personnel, to be secured by a safety harness to the building. Such personnel will therefore require anchorages in the external walls to which they can readily secure the harness.

Moreover, it is an advantage if, after use, the anchorage can be removed and re-used elsewhere.

In this manner a window cleaner, for example, need only carry one or two anchorage devices which he can use over and over again as he moves about the external surface of a high building.

One known form of eyebolt anchor comprises a threaded metal sleeve having at one end a longitudinally slotted and tapered bore in which is positioned a complementary tapered solid insert. When a suitable hole has been drilled into a wall the sleeve is inserted into the bottom of the hole and the insert is forced, by means of a special punch and a hammer, into the taper to expand the slotted end of the sleeve to grip the bore of the hole. An eyebolt can subsequently be screwed into the threaded sleeve. After use the eyebolt is unscrewed and removed, leaving the sleeve in the hole which is then closed with a removable plug. To use the eyebolt again at another location a fresh sleeve plus insert assembly is required.

According to the present invention there is provided an anchor device comprising a bolt having the end portion of the stem remote from the bolt head provided with a screw thread, the stem carrying adj acent the bolt head a sleeve of resiliently deformable material and an eye-ring having a screw-threaded bore in engagement with the threaded end portion of the stem, whereby axial compressive pressure on the sleeve by screwing of the eye-ring or another screw-threaded part causes radial expansion ofthe deformabie sleeve.

In a preferred embodiment of the invention the surface of the bolt head remote from the stem is adapted for engagement with a tool for rotating the bolt relative to the eye-ring.

Embodiment of the invention will now be described with reference to the accompanying draw ings, in which:- Fig. 1 illustrates a first form of eyebolt anchor, Fig. 2 illustrates a second form of eyebolt anchor, Fig. 3 illustrates the use of an eyebolt anchor of the form shown in Fig. 1 in a cavity structure, and Fig. 4 illustrates a tool for use in conjunction with the eyebolt anchors shown in the preceding figures.

The eyebolt anchor in Fig. 1 comprises a bolt 1 of which the end portion 2 of the stem 3 is provided with a screwthread. A resilient sleeve 4, e.g. of rubber or unfiiled PVC, which is a sliding fit on the stem 3, abuts against the head 5 of the bolt 1. A metal sleeve 6 in which is also a sliding fit on the stem is interposed between the resilient sleeve 4 and an annular eye-ring 7. The eye-ring 7 has a radial bore 8 which is threaded so that it can be screwed onto the end portion 2 of the stem 3. The metal sleeve 6 and the resilient sleeve 4 both have an external diameter substantially the same as the diameter of the bolt head 5. In use a hole 10 is first drilled into a wall 11, of suitable diameter and depth to accommodate the major part of the eyebolt anchor, which is then inserted into the hole.After inserting the eye-ring is screwed down causing the metal sleeve to exert axial compressive pressure on the resilient sleeve, resulting in radial expansion of the resilient sleeve which grips tightly in the hole 10. The eye-ring is screwed down until sufficient grip is achieved. To remove the eyebolt anchor it is only necessary to unscrew the eye-ring until all compressive pressure on the resilient sleeve has been removed, when the eyebolt anchor can be easily withdrawn from the hole.

To assist in the fixing of the eyebolt anchor the bolt head 5 can be provided with, for example, a hexagonal recess 9 into which a suitable key, e.g. an Allen key, can be inserted, thus allowing an initial compression of the resilient sleeve to be effected.

This initial compression expands the sleeve enough to allow the eyeboltanchorto be forcefully pushed into the hole with sufficient grip to prevent the sleeve and the bolt from turning when the eye-ring is further screwed onto the bolt to achieve the desired working grip.

An alternative form of eyebolt anchor is shown in Fig. 2 in which a threaded nut 20 is interposed between the eye-ring 7 and the metal sleeve 6. In this case the expansion of the resilient sleeve 4 is effected by tightening the nut 20. The eye-ring 7 can then be removed leaving the remainder of the anchor in situ in the wall for future use. The use of the nut 20 also means that before the eye-ring 7 is replaced on the threaded end portion 2 on subsequent occasions the workman can apply further compressive pressure if required. However, this form of eyebolt anchor can likewise be removed from the hole if desired once the nut has been unscrewed. The nut can be either a hexagonal nut, turned by the use of a box spanner (not shown), or a cylindrical nut with slots 22 turnable by a tubular spanner (not shown) formed with complementary tongues which engage the slots.In this example the head 5 of the bolt is a so-called round head and is provided with slot to receive a screwdriver blade for pre-expansion purposes.

Fig. 3 shows how the eyebolt anchor of the invention can be utilised in a thin wall structure, such as a leaf of a cavity wall. The eyebolt anchor extends right through the wall 10 and the resilient sleeve can expand to a greater diameter than that of the hole, thus providing an even more secure anchorage for the eye-ring 7.

To assist in the placement and removal of eyebolt anchors according to the invention use of a tool such as that shown in Fig. 4 is advantageous. The tool has a handle 41 and an enlarged head portion 42. The head portion has on one side a flat face 43 to act as a hammer for assisting the insertion of the anchor into the hole. The rear of the head portion is formed with a rounded profile 44. To assist in the removal of an anchor from a hole the handle 41 is slipped through the eye-ring 7 once the latter has been unscrewed sufficiently to remove all the compressive force on the resilient sleeve. Movement of the free end of the handle results in the rounded profile 44 acting as a fulcrum against the wall surface, the handle thus providing leverage to draw the eyebolt anchor from the hole in the wall. The handle 41 itself is usable as a tommy bar for screwing and unscrewing the eyebolt 7. The end 45 of the handle can conveniently be shaped to provide a key or blade to fit the recess or slot in the head 5 of the bolt 1. In the interest of safety it may be advantageous to have the tool of Fig. 4 permanently attached to the eye-ring 7 by means of a cord or chain, thus reducing the risk of accidentally dropping tools from high buildings. This is especially so where the eyebolt anchorage is to be used by a window cleaner or the like, when the anchor is going to be repeatedly re-used, probably several times during the course of one day.

Claims

1. An eyebolt anchor device comprising a bolt having the end portion of the stem remote from the bolt head provided with a screw-thread, the stem carrying adjacent the bolt head a sleeve of resiliently deformable material and an eye-ring having a screw-threaded bore in engagement with the threaded end portion of the stem.

2. A device according to claim 1 further including a rigid sleeve between the deformable sleeve and the screw-threaded eye-ring or other screw-threaded part.

3. A device according to claim 1 or 2 further including a nut in screw-threaded engagement with the stem between the rigid sleeve and the eye-ring.

4. A device according to claim 1,2 or 3 wherein the surface of the bolt head remote from the stem is adapted for engagement with a tool for rotating the bolt relative to the eye-ring.

5. A device according to claim 4 wherein the bolt head is cylindrical and the surface of the bolt head remote from the stem is formed with axial recess shaped to receive a key for applying rotation to the bolt.

6. A device according to claim 4 wherein the bolt head surface is slotted.

7. A device according to any preceding claim wherein the resiliently deformable sleeve is made of rubber.

8. A device according to any one of claims 1 to 6 wherein the resiliently deformable sleeve is made of unfilled PVC.

9. A device according to claim 2 or any one of claims 3-8 when dependent on claim 2 wherein the rigid sleeve is made of metal.

10. An anchor device substantially as described with reference to Figs. 1-3 of the accompanying drawings.

11. A tool for use with an eyebolt anchor device as claimed in any preceding claim substantially as described with reference to Fig. 4 of the accompanying drawings.

12. An anchorage kit of parts comprising an anchor device according to any one of claims 1 - 10 together with a tool according to claim 11.