This invention relates to an anchoring device, and in particular but not exclusively to an expansible bolt anchoring device.

Expansible bolt anchoring devices are widely used for attaching articles to, for example, the surfaces of masonry or brick walls or structures. A typical anchoring device comprises a segmented right cylindrical shell, and an expansion member located in the shell. The expansion member may be in the form of a nut mounted on che bolt (a "loose bolt" anchor) or may form the head of the bolt (a

"projecting bolt" anchor) . The expansion member is initially positioned at the inner end of the segmented shell such that rotation of the bolt, or rotation of a nut on the shank of the bolt, will draw the expansion member into the shell and radially expand the shell. Thus, when the device is located in a hole of corresponding diameter to the segmented shell, tightening the bolt or nut expands the shell radially to engage the hole wall .

Tightening of the bolt or nut in the desired "one- handed" manner requires that the shell engages the hole wall and is held against rotation in the hole. This requires that the shell is a snug fit in the hole, which is often difficult to achieve. In the absence of such a close fit, the shell must be held or jammed in the hole by some other means, such as part-filling the hole with packing material.

The three or four segments which typically form the shell are conventionally formed of cast or pressed metal. The segments are held together in the desired cylindrical form around the bolt by a ferrule placed over one end of the segments. A spring clip also encircles the segments intermediate their ends to prevent the shell segments from falling apart. Not surprisingly, the assembly of expansible bolt anchoring devices is a relatively difficult and time-consuming task and is still, in the main, a manual operation.

The majority of segments utilised in existing anchoring devices are relatively rigid and are only subject to minor deformation on the bolt or nut being tightened to expand the shell to engage the segments with the hole wall. Accordingly, the segments tend to engage the hole wall with a point or line contact, such that pressure forces experienced by the hole wall are relatively high and tend to cause a degree of crushing of the masonry or brickwork. A limited degree of such crushing may be advantageous, serving to anchor the shell securely in the hole. However, in softer materials the surrounding stone may crumble to such an extent that the device will not remain in the surface, requiring drilling of a larger hole and use of a larger diameter device. Numerous proposals have been made to provide bolt anchoring devices with solid resilient sleeves in place of the conventional segmented metal sleeves. Devices of this type are described in GB-A-685643, GB-A-1530344 , GB-A-

774002, GB-A-886400, EP-A-0494741, ΞP-A-0105829 and US-A- 4472088. However, these devices have not been adopted by industry and the resilient sleeve anchor bolts currently available on the market are provided for non-load bearing applications only.

According to the present invention there is provided an anchoring device comprising: a resilient sleeve for receiving an elongate member; and first and second stopper portions for location on the elongate member at respective ends of the sleeve, the sleeve and at least one of the stopper portions comprising polymer-based materials, whereby movement of the stopper portions towards one another causes the sleeve to expand radially.

According to another aspect of the present invention there is provided an anchoring device comprising: a resilient sleeve for receiving an elongate member; and first and second stopper portions for mounting on respective ends of the sleeve, whereby movement of the stopper portions towards one another causes the sleeve to expand radially.

As the stopper portions are mounted on the sleeve, the assembled sleeve and stopper portions may be stored, transported and supplied to users as an unitary part . The part may be supplied on its own or with an appropriate elongate member, typically a bolt and nut. Preferably, the stopper portions include tubular parts extending into the respective ends of the sleeve. The tubular parts may be an interference fit in the respective sleeve ends or may snap

fit in the respective sleeve ends.

According to a further aspect of the invention there is provided an anchoring device comprising: an elongate member defining a threaded shank and a head; a threaded nut for location on the shank; a resilient sleeve for receiving the elongate member; and inner first and outer second stopper portions at respective ends of the sleeve between the head and nut, the inner stopper portion engaging one of the head and nut to resist relative rotation thereof, whereby movement of the stopper portions towards one another, by relative rotation of the elongate member and the nut, causes the sleeve to expand radially.

Engaging the head or nut with the inner stopper in this manner facilitates installation of the device. Preferably, the first stopper portion captures one of the head and nut . The head and nut are preferably of corresponding form such that the elongate member may be positioned with either the head or the nut restrained by the first stopper, that is the elongate member orientation is reversible. This permits a single device to be provided for both loose bolt and projecting bolt applications. Typically, the first stopper portion will define a hexagonal recess.

According to a still further embodiment of the present invention there is provided an anchoring device for securing a component to a body, the device comprising an elongate member defining a threaded shank and a head; a threaded nut for location on the shank; a resilient sleeve

for receiving the elongate member; and inner first and outer second stopper portions for location on the elongate member at respective ends of the sleeve between the head and nut, the outer stopper portion for extending from a hole formed in the body and through a hole in the component of corresponding diameter to the body hole, whereby rotating the elongate member relative to the nut moves the stopper portions towards one another and radially expands the sleeve. According to yet another aspect of the present invention there is provided a method of securing a component to a body, the method comprising the steps of: providing an anchoring device comprising an elongate member defining a threaded shank and a head; a threaded nut for location on the shank; a resilient sleeve for receiving the elongate member; and inner and outer stopper portions for location on the elongate member at respective ends of the sleeve between the head and nut; forming a hole in the body; forming a hole through the component of corresponding diameter to the body hole; aligning the hole in the component with the hole in the body; locating the anchoring device in the holes such that the sleeve in positioned in the body and the outer stopper portion extends from the body and through the component; and rotating the elongate member relative to the nut to

move the stopper portions towards one another and radially expand the sleeve.

These aspects of the present invention facilitate mounting of components to bodies as the holes which extends through the component and into the body are of the same or similar diameter. It is therefore relatively easy to align the component hole with the body hole, in contrast to prior arrangements in which the body hole is larger than the component hole and it is not possible to, for example, drill both holes in a single operation, or drill the body hole through a previously formed component hole.

In use, embodiments of the anchoring devices of these various aspects of the invention may be located in holes in, for example, a masonry or brick wall, and the stopper portions then brought together to expand the sleeve to engage with the wall. As the sleeve is formed of resilient material the contact area between the sleeve outer surface and the hole wall is likely to be relatively large, and thus hold the device securely in the hole. The relatively large contact area between the sleeve and the hole wall also minimise the pressure forces experienced by the material defining the hole wall, facilitating secure location in softer materials such as sandstone and breeze block. The sleeve is also capable of expanding in a non- uniform manner, facilitating secure location in irregularly shaped holes, and allowing holes to be sealed by the sleeve. This also facilitates anchoring of the device in cavity walls and the like.

The resilient sleeve will also tend to make the device less prone to loosening in applications in which the device experiences vibration. Further, the resilient sleeve facilitates removal of the device, as the sleeve will tend to contract radially when permitted to expand longitudinally. A resilient sleeve is also likely to require lower forces to expand when compared to conventional anchors with metal segments, such that there is greater flexibility in the form of tool engaging nuts and bolt heads that may be provided to allow setting of the anchor.

Preferably, the sleeve is of elastomeric material, most preferably a natural rubber. Most preferably, the sleeve material is selected such that the sleeve will only experience elastic deformation in use, however in certain applications materials which are also deformed plastically may be utilised. Preferably also, the wall of the sleeve is continuous.

Preferably also, the stopper portions are of a relatively rigid material, such as polypropylene. The stopper portions may be provided separately, or may be integral with the sleeve. In certain embodiments the first stopper portion may itself define a thread for engagement with the threaded inner end of a bolt or the like. Preferably also, the stopper portions include tubular parts for extending into the respective ends of the sleeve. Most preferably, said portions are of reduced cross section. In one embodiment, the sleeve defines a

throughbore of substantially constant diameter and said parts define bores of corresponding diameter. Accordingly, the ends of the sleeve must deform to receive the stopper portions. To accommodate this deformation the ends of the sleeve may be of reduced cross section. A reduction in cross-section of the sleeve inner end has also been found useful in ensuring that deformation of the sleeve is initiated at the inner end.

These and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a sectional view of an anchoring device in accordance with an embodiment of the invention shown located in a hole; Figure 2 is a sectional view of a sleeve of the device of Figure 1;

Figure 3 is a sectional view of a first stopper of the device of Figure 1;

Figure 4 is a sectional view of a second stopper of the device of Figure 1;

Figure 5 is a sectional view of the anchoring device of Figure 1, with the bolt reversed;

Figure 6 is a sectional view of a number of anchoring devices in accordance with further embodiments of the present invention;

Figure 7 is an assembly drawing of an anchoring device in accordance with another embodiment of the present invention; and

Figure 8 is an exploded view of the device of Figure 7.

Reference is first made to Figure 1 of the drawings, which illustrates an anchoring device 10 in accordance with an embodiment of the present invention. The device 10 is illustrated located in a hole 12 which has been drilled into a wall 14. The device 10 comprises a rubber sleeve

16, a bolt 18 extending through the sleeve 16, and first and second stoppers 20, 21 mounted on the bolt 18 and engaging the respective ends of the sleeve 16. In the

"loose bolt" arrangement illustrated in Figure 1, the bolt head extends from the hole 12, while a nut 24 is located on the inner end of the bolt 18, within the first stopper 20

(Figure 5 illustrates a "projecting bolt" arrangement, in which the bolt 18 is reversed) .

Reference is now also made to Figures 2, 3 and 4 of the drawings, which illustrate the sleeve 16, first stopper 20 and second stopper 21, respectively. The sleeve 16 is formed of moulded natural rubber and defines a throughbore 26 of constant diameter. The sleeve wall 28 tapers towards the sleeve ends 30, 31 such that the sleeve 16 is generally barrel-shaped.

The stoppers 20, 21 are formed of a relatively rigid material, in this example polypropylene. Each stopper 20, 21 defines a respective throughbore 32, 33 of the same diameter as the sleeve bore 26 and includes a reduced cross-section portion 34, 35 which, in use, is located within the respective ends of the sleeve bore 26, as shown

m Figure 1. The external surface of each portion 34, 35 has a rough finish to prevent the stoppers 20, 21 from turning relative to the sleeve 16. The first stopper ₂₀ includes a larger diameter portion 36 abutting the inner end of the sleeve 16. The portion 36 is of similar diameter to the central portion of the sleeve 16 and defines a hexagonal recess 38 to receive the nut 24. The recess wall defines a lip 40 to facilitate retention of the nut 24 m the recess 38. The second stopper 21 also includes an enlarged cross- section portion 42 of the same diameter as the central portion of the sleeve 16, for abutting the outer end of the sleeve 16. Further, the stopper 21 defines a tapered flange 44 which, in use, engages the hole edge 46. It will be noted that the device 10 only consists of five parts, including the nut 24 and bolt 18. The device 10 is assembled simply by pushing the reduced cross-section stopper portions 34, 35 into the ends of the sleeve 16, locating the nut 24 m the recess 38, and passing the bolt 18 through the sleeve 16 and stoppers 21, 22 to loosely engage the nut 24. If it is desired to provide a "projecting bolt" anchor, rather than a "loose bolt" anchor as illustrated in Figure 1, the bolt 18 is simply reversed with the bolt head 22 being located m the recess 38 and the nut 24 being located on the end of the bolt 18 projecting from the second stopper 21, as illustrated in Figure 5.

If desired, the sleeve 16 and stoppers 21, 22 may be

moulded together to further minimise the assembly steps required. The sleeve 16 and stoppers 21, 22 may also be supplied to customers without the nut 24 and bolt 18; the customer may then provide a nut and bolt suited to their own particular needs.

In use, the device 10 is located in a hole 12 as illustrated in Figure 1, and in this example is shown securing a plate 48 to the wall 14. The bolt 18 is then rotated using a suitable tool to engage the bolt head 22. The sleeve 16 and stoppers 20, 21 may be restrained from rotating by contact with the hole wall, and also the tapered flange 44 on the second stopper 21 will engage the hole edge 46, in addition to centring the outer end of the device 10 in the hole 12. Rotation of the bolt 18 relative to the rest of the device 10 will cause the captured nut 24 to be drawn outwardly, pulling the first stopper 20 outwardly, and thus longitudinally compressing the sleeve 16. Such longitudinal compression results in radial expansion of the sleeve 16 into contact with the hole wall. Testing has shown that the radial expansion of the sleeve 16 tends to be initiated adjacent the first stopper 20, and then continues along the sleeve 16 towards the second stopper 21. The sleeve 16 will continue to expand until substantially all of the sleeve outer surface is in contact with the bore wall. This large contact area serves to locate the device 10 in the wall 14 securely, and will also tend to seal the hole 12.

To remove the device 10, the bolt 18 is rotated in the

97/32141 PC17GB97/00579

12 opposite direction, allowing the resilient sleeve 16 to expand longitudinally and contract radially until it returns to its original, undeformed shape and may be removed from the hole 12. Although the device 10 is illustrated located in a hole 12 in a solid wall 14, testing has indicated that the device 10 may be secured in cavity walls and the like. As noted above, deformation of the sleeve 16 is initiated adjacent the first stopper 20, and thus if the inner end of the device 10 is located within a cavity the sleeve 16 will expand in the cavity to a diameter larger than the hole in the adjacent brick work. The sleeve 16 will also tend to expand to fill the hole, such that the device is held securely in the wall. For projecting bolt applications, the relatively low forces necessary to expand the sleeve 16 allow the nut 24 to be replaced by other fasteners, particularly low-profile fasteners providing a flange finish on the wall, for example a non-ferrous threaded cap adapted to be rotated using a pin wrench.

Reference is now made to Figure 6 of the drawings, which illustrates anchoring devices 50, 52, 54 in accordance with further embodiments of the invention, shown securing components 74, 76, 78 to a body 67. The devices share a number of features with the device 10 described above and these common features will not be described again in detail. The devices 50, 52, 54 differ primarily from the device 10 in the nature of the outer second stoppers

56, 58, 60: the stoppers are relatively long and are each intended to extend from the locating hole 62, 64, 66 in the body 67 and through a hole 68, 70, 72 of corresponding diameter in the component 74, 76, 78. A washer 80 is located between the outer end of the stopper and the bolt head 82, 84, 86.

This arrangement facilitates mounting of components using loose bolt anchors: with conventional anchors the holes in the body would be of larger diameter than the hole in the component, making alignment of the holes more difficult, and requiring the provision of projecting bolt anchors . Also, with the present arrangement, the holes may be drilled in a single operation, or the hole in the body drilled through the hole in the component, thus assuring correct alignment.

Reference is now made to Figures 7 and 8 of the drawings, which illustrate an anchoring device 90 in accordance with a further embodiment of the present invention. The device 90 is similar to the devices illustrated in Figure 6, but includes a second spacer or stopper 92 having a fluted outer surface, which reduces the volume of material required to form the stopper 92, and the sleeve 94 is tapered only at its inner end, to ensure that deformation of the sleeve 94 commences at the inner end. It will be clear to those of skill in the art that the above-described embodiments are merely exemplary of the present invention, and that various modifications and improvements may be made thereto without departing from the scope of the present invention.