GB2211523A

GB2211523A - Guiding drill rods

Info

Publication number: GB2211523A
Application number: GB8725222A
Authority: GB
Inventors: Stefan Schoerling
Original assignee: K D ENGINEERING PLASTICS LIMIT
Current assignee: K D ENGINEERING PLASTICS LIMIT
Priority date: 1987-10-28
Filing date: 1987-10-28
Publication date: 1989-07-05
Also published as: GB8725222D0

Abstract

A device for guiding a drill comprising an elongate guide member (10) slidable on a rod, the guide member having a maximum width marginally less than the diameter of the hole being drilled and being made wholly from an elastomeric material, such as polyurethane. The member has longitudinal flutes (16) to allow passage of debris. <IMAGE>

Description

DRILL GUIDE This invention relates to a device which is intended to guide a drill as it penetrates layers of rock or the like.

When drilling holes of a substantial depth, for example in mines, quarries, oilfields or the like, it is of course necessary to add several extension rods to the drill bit. Naturally it is a problem ensuring that the drill bit continues in a straight line because as more extension rods are fitted the drill bit tends to deflect. If the hole being drilled is fairly deep it is quite possible that the drill bit could end up travelling in a totally different direction to that required.

If has previously been suggested that metallic drill guides could be used to alleviate the problem but these have proved to be inefficient because they are relatively heavy and they do not tend to have a sufficiently high wear resistance.

It is an object of the present invention to overcome or reduce the above disadvantages.

According to the present invention there is provided a device for guiding a drill comprising an elongate guide member slidable on a rod, the guide member having a maximum width marginally less than the diameter of the hole being drilled and being made wholly from an elastomeric material.

Preferably the guide member is substantially cylindrical but has a plurality of cut-outs along its length at its periphery to allow the passage of debris.

Preferably the guide member is constructed from plastics material, such as polyurethane, although other materials such as rubber could also be used.

Guide members would preferably occupy the whole of the drill rod, and possibly the whole of the first extension rod to minimise any deflection, and thereafter fewer guide members would be located on each rod depending on the drilling demands.

Preferably spacer sleeeves, also made of plastics material, are located on the extension rods between the guide members to ensure that the guide members occupy the correct position.

The spacer sleevees preferably have an external diameter substantially less than the maximum width of the guide members to allow passage of debris.

The drill is preferably powered by a compressed air supply and the compressed air also serves to drive debris out of the hole being drilled.

The invention will now be described further, by way of example only, with reference to and as illustrated in the accompanying drawings, in which: Figure 1 is an illustration of a guide member in accordance with the invention; and Figure 2 is a schematic illustration of how the guide members and spacer sleeves are used with a drill.

Referring to the drawings, an elongate guide member 10 has an inner cavity 12 which enables it to slide an extension rod 14. The guide member has an integral outer cylindrical section which is "fluted", i.e. it is provided with a plurality of cut-outs 16 at its periphery to allow debris to pass the guide member. The guide member is typically manufactured by pouring liquid polyurethane-into a suitable mould and curing, although the guide member could also be injection or compression moulded in large scale operations.

In use, as can be seen in figure 2, a drill head 18 drills a hole 20 and guide members 10 are situated on extension rods 14 to ensure that the drill progresses in a straight line. The first extension rod, is generally filled with guide members for maximum stability. The second extension rod may also be filled with guide members, although this is not shown in the drawing, and thereafter one guide member is usually fitted on each extension rod at the front thereof. A plurality of spacer sleeves 22 are also located on the extension rods to ensure that the guide members occupy the correct position.

The drill is typically a pneumatic drill which is powered by compressed air. As the drill penetrates the rock the compressed air flushes the debris out of the hole.

The cut-outs 16 allow the debris to pass the guide members 10 and the spacers do not interfere with the passage of debris since they have a diameter which is substantially smaller than the guide members. The required capacity of the compreessor providing the compressed air is dependant upon the area available for flushing debris. The use of spacer sleeves 22 reduces this area which increases the speed of the airflow thereby assisting flushing.

The guide members and spacers have a high abrasion resistance which gives them a long life and they conveniently protect the extension rods from wear from abrasive material.

A distinct advantage of the invention is that it provides a device for guiding a drill which is resilient, relatively light and simple and inexpensive to manufacture.

Claims

1. A device for guiding a drill comprising an elongate guide member slidable on a rod, the guide member having a maximum width marginally less than the diameter of the hole being drilled and being made wholly from an elastomeric material.

2. A device as claimrd in claim 1 wherein the member is substantially cylindrical but has a plurality of external longitudinal channels to allow the passage of debris.

3. A device as claimed in eiher of claims 1 or 2 wherein the guide member is constructed from plastics material.

4. A device as claimed in claim 3 wherein the plastics material isas polyurethane.

5. A device as claimed in any of claims 1 to 4 wherein the guide members occupy the whole of the drill rod.

6. A device as claimed in claim 5 wherein the guide members occupy the whole of the first extension rod to minimise any deflection.

7. A device as claimed in claim 6 wherein fewer guide members are located on each successive rod depending on the drilling demands.

8. A device as claimed in any of claims 1 to 7 wherein spacer sleeeves are located on the extension rods between the guide members to ensure that the guide members occupy the correct position.

9. A device as claimed in claim 8 wherein the spacers are also made from plastics material.

10. A device as claimed in either of claims 8 or 9 wherein the spacer sleeves have an external diameter substantially less than the maximum width of the guide members to allow passage of debris.