GB2205622A

GB2205622A - Protective washer for rock bolt end

Info

Publication number: GB2205622A
Application number: GB08813309A
Authority: GB
Inventors: Barry Gibson
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-06-06
Filing date: 1988-06-06
Publication date: 1988-12-14
Also published as: GB8813309D0; GB8713303D0

Abstract

A protective washer assembly for rock bolt ends comprises a square washer 10 with a central aperture 12, and a hollow truncated pyramidal cover 14 mounted on the washer 10 and provided with a central aperture 16 coaxial with the aperture 12 and large enough to permit access to the rock bolt end and a nut screwed onto it. The cover 14 protects the bolt end against damage, and people and machinery from damage by the bolt end. <IMAGE>

Description

Improved Washer Plate Arrangement The present invention relates to a washer arrangement and particularly but not exclusively to a washer arrangement for rock bolts.

During rock bolting it is usual, after a bolt has been fixed in position, to locate a washer plate over the protruding end of the bolt, to provide protection for this free end of the bolt and also to provide protection for people and machinery when coming into contact with this free end. These plates are held in place against the fixture into which the bolt has been secured by a nut on the threaded free end of the bolt.

Conventionally these washer plates have simply comprised a flat plate provided with a substantially central aperture. A number of disadvantages are encountered when such plates are used, for example the free end of the rock bolt and the nut thereon project from the washer plate and may injure persons or damage machinery such as the pneumatic tyres on some machines when these persons or machines come into contact with the bolt. Also the rock bolt and nut may themselves become damaged upon such contact. Furthermore cables and hoses may become tangled or hooked upon the bolts.

According to the present invention there is provided a washer arrangement for a rock bolt, the arrangement comprising a washer plate adapted to so locate on a free end of a rock bolt whereupon attachment means can be located on the bolt to secure the plate in position, and cover means provided on the plate and adapted to surround the attachment means and the free end of the bolt but permit access thereto.

Preferably the washer plate includes an aperture through which the bolt may pass to receive the attachment means in the form of a nut threaded onto the bolt.

Access to the nut may be provided by an aperture in the cover means, and this aperture may be substantially coaxial with the aperture in the plate. A cylindrical sleeve may be provided, extending between the plate and the cover means, substantially coaxial with said apertures.

Preferably the cover means comprises a member in the form of a truncated pyramid.

Preferably also the washer plate arrangement is formed from mild steel, and the cover member plate and sleeve may be joined by welding.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a plan view of a washer plate arrangement according to the present invention; Fig. 2 is a cross-sectional view of the washer plate arrangement of Fig. 1; and Fig. 3 is a perspective view from above of the washer plate arrangement of Fig. 1.

The drawings show a washer plate arrangement that is suitable for use with rock bolts. The arrangement comprises a base member in the form of a substantially square washer plate 10 with a substantially central aperture 12 provided therein. The aperture 12 is of a size that a rock bolt (not shown) can be a slidingly fitted therethrough.

A cover 14 is mounted on an upper face of the plate 10, and is in the form of a hollow truncated pyramid with an open substantially square base of a size slightly smaller than the plate 10. A substantially central aperture 16 is provided in an upper face 18 of the cover member 14, and is coaxial with the aperture 12 but of a larger diameter. The height of the cover 14 above the plate 10 is such that, when fitted on the bolt, the latter does not protrude beyond the member 14.

A cylindrical sleeve 20 is provided, extending between the plate 10 and the cover 14, and is coaxial with the apertures 12 and 16. The internal diameter of the sleeve 20 is slightly less than that of the aperture 16, and the external diameter is slightly greater than that of the aperture 16. The sleeve 20 provides a guide between the apertures 12 and 16, and also provides support for the cover member 14.

The washer plate arrangement can, for example, be made from mild steel by the following method. The plate 10 is cut to shape and the aperture 12 is formed therein by punching. The cover 14 is formed from a suitably sized sheet by punching the aperture 16 therein and pushing the sheet onto a requisite shaped former. The sleeve 20 is cut from a tube of the required diameter and arc-welded onto the plate 10.

The cover 14 is placed onto the plate 10 and welded thereto. The cover 14 may also be welded through the aperture 16 to the sleeve 20.

There is thus described a washer plate arrangement suitable for use with rock bolts on floors, walls or ceilings. The plate arrangement is secured to the fixture by a nut (not shown) located through the aperture 16 and tightened on the end of the bolt. The plate arrangement prevents injury to persons or damage to equipment by avoiding contact with the free end of the rock bolt. The plate arrangement also permits vehicles with pneumatic tyres to be driven over the rock bolts and prevents cables and hoses snagging on such bolts and perhaps becoming damaged. As this washer plate arrangement prevents the free end of the rock bolt and the nut thereon becoming damaged, the plate arrangement may be re-used at another location.

Various modifications may be made to the above example without departing from the scope of the invention. For example, the above described example is approximately 15 cm square but any required size of plate may be made. The thickness of material can be varied to suit the working conditions. Materials other than mild steel can be used. It may not be necessary for the plate arrangement to include a cylindrical sleeve if the plate arrangement is not to incur heavy loading, such as on rock bolts in ceilings.

Claims

Claims:

1. A washer arrangement for a rock bolt, the arrangement comprising a washer plate adapted to so locate on a free end of a rock bolt whereupon attachment means can be located on the bolt to secure the plate in position, and cover means provided on the plate and adapted to surround the attachment means and the free end of the bolt but permit access thereto.

2. An arrangement according to Claim 1, in which the washer plate includes an aperture through which the bolt may pass to receive the attachment means means in the form of a nut threaded onto the bolt.

3. An arrangement according to Claim 1 or 2, in which access to the nut is provided by an aperture in the cover means.

4. An arrangement according to Claim 3 when dependent on claim 2, in which the aperture in the cover means is substantially coaxial with the aperture in the plate.

5. An arrangement according to Claim 4, in which a cylindrical sleeve is provided, extending between the plate and the cover means, substantially coaxial with said apertures.

6. An arrangement according to any of the preceding claims, in which the cover means comprises a member in the form of a truncated pyramid.

7. An arrangement according to any of the preceding claims, in which the washer plate arrangement is formed from mild steel.

8. An arrangement according to any of the preceding claims, in which the cover member plate and sleeve are joined by welding.

9. A washer arrangement for rock bolts substantially as hereinbefore described with reference to the accompanying drawings.

10. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.