GB2028693A

GB2028693A - Mining drill boom

Info

Publication number: GB2028693A
Application number: GB7834769A
Authority: GB
Original assignee: GRIMSHAW G
Current assignee: GRIMSHAW G
Priority date: 1978-08-26
Filing date: 1978-08-26
Publication date: 1980-03-12
Also published as: DE2932062A1; FR2438153B1; GB2028693B; FR2438153A1

Abstract

A mining drill boom, e.g. for use in drilling shot holes for blasting in coal mines, has a base plate 1 and a drill carriage-mounting plate 8 linked to it by three elongate members 3, 9 universally coupled to each plate. The couplings are in the same triangular configuration so that the plates are maintained parallel when moved vertically or horizontally. To provide true circular movement of the drill, the base plate 1 is mounted so as to rotate about an axis normal to the plate by gearing 2. The drill carriage 11 is pivotally mounted 12, 13 on the carriage mounting plate in such a way as to permit movement in both planes perpendicular to the surface of the plate, and has a drill carrying part 15 slidably mounted relative to another part 14 on guides 16. Pivoting and sliding movements are carried out by hydraulic jacks 20-25. <IMAGE>

Description

SPECIFICATION Mining drill boom This invention relates to a mining drill boom, A mining drill boom is an apparatus upon which a drill may be mounted and which permits the drill to be presented to the rock face, or other surfaces into which a hole is to be drilled, at a desired location on and angle to the face, and to be held in such a position during the drilling operation.

An example of the use of a mining drill boom is in the cutting of roadways in coal mines. The rock is cut by drilling a plurality of shot-holes in a predetermined pattern, charging the holes with explosive and firing the explosive. The procedure is repeated around the initial cavity formed until the required amount of rock has been removed.

Typically, two alternative patterns of holes are used. In a "burn cut", a ring of parallel holes is drilled near the centre of the tunnel face and each hole is packed with a heavy charge of explosive to blow or "burn" outa plug of rock. Further holes are then drilled around the void so produced and further rock is blown into this void, to be removed. This is repeated to produce the required tunnel profile. In a "wedge cut", the holes are not drilled parallel but in a convergent pattern, a lower charge of explosive than in the "burn cut" being used for blasting.

Afurther use for mining drill booms is in the drilling of holes for roof anchor bolts, which typically require holes extending into the roof of the tunnel approximately normally to the tunnel axis. Expansion bolts or resin-bonded rods or bolts are secured in the holes so formed and tensioned by means of nuts screwed on to the rods or bolts and acting on plates positioned over the holes, to stabilise the roof.

Two main types of mining drill boom are known.

The first, the pantograph type of boom, has mechanical or hydraulically-operated linkages to maintain the drill carriage, upon which a drill may be mounted, parallel to a predetermined axis as the boom is raised or lowered. The pantograph boom normally has only two hydraulically-controlled movements, namely raising and lowering, and rotation. The boom is also arranged to provide tilting, rotating and "crowding" or advancing movements of the carriage relative thereto. This type of boom readily allows holes to be drilled parallel to a chosen axis, for example in a circular pattern, but it is not suitable for drilling holes for roof bolting.

The second main type of boom is the "Universal"' boom, having up to four hydraulically-controlled movements in addition to the carriage movements.

The additional boom movements are slewing to the left or right by up to say, 45 degrees, and boom extension. However, the mechanical or hydraulically-operated linkages which maintain the carriage angle in the pantograph type cannot be used with this type of boom. The universl boom allows holes to be drilled in any of the normally-required directions and so is very suitable for drilling a wedge cut, and fordrilling holes for roof bolts, However, drilling parallel holes is much moretime-consumingthan with the pantograph type of boom and requires much greater skill on the part of the operator, because the boom does not provide automatic parallelism.

Afurthertype of boom has been proposed which combines the capabilities of the two main types of boom previously described. In this further type of booms two plates are joined together by three parallel rods arranged in a triangular configuration and universally jointed to each plate. With one plate fixed, the other plate may be moved to any position and the rods will maintain it parallel to the fixed plate In a known boom of this type, the carriage is mounted on a gear drive on the end ofthe boom so as to beableto be rotated abouta longitudinal axis.

Thus, the carriage is rotated to lie beneath the boom when drilling holes at a short distance above floor level, since the minimum height at which drilling could take place would otherwise be limited by the boom interfering with the rear end of the carriage. A disadvantage of this arrangement is that the gear drive permitting such rotation is relatively heavy and thus the additional load which can be placed on the boom bythe drilling equipment is very limited, unless th boom members are made very large to take the additional loads required by, for example, hydraulic percussive hammer drills. For locations where size is important, such as coal mines, this is not practical. A further disadvantage is thatonly two positions of carriage rotation can be used, namely above and below the boom.This is because if the carriage were rotated to one side of the boom it would be necessary to provide the boom with some means of limiting its normal sideways orslewing movement to prevent the carriage being damaged by engagementwith the boom as the boom passes the mid-point of its slewing motion. This limitation on the carriage position also means that this type of boom cannot drill parallel holes in a circular pattern without the use of considerable skill by the operator.

According to the present invention there is provided a mining drill boom comprising a base plate and a drill carriage-mounting plate linked thereto by means ofthree elongate members universally coupled to each plate in the same triangular configuration whereby the plates remain substantially parallel one to the other during relative displacementthereof, the base plate being rotatably mounted about an axis substantially normal to the base plate.

Preferably a drill carriage is pivotally mounted on the carriage-mountng plate so as to allow rotation of the carriage in at least one of the two planes perpendicular to the surface ofthe carriagemounting plate. Thecarrfage may also be slidably mounted to permit advancing or "crowding" movements thereof to compensate forthe movement away from the vertical surface to be drilled when the boom is raised.

Any of the movements of the boom or the carriage relative thereto may be effected by means of hydraulic rams pivotally mounted on the boom or carriage.

The base plate may be carried by a gear drive, which may be mounted on a wheeled or tracked vehicle by which the boom may be moved to a desired location for drilling.

By providing a rotable boom with automatic parallelism, and by providing the rotation at the base plate instead of at the carriage, the advantages of both the main types of boom are obtained without the limitations imposed by the weight of the drive gear. Thus any type of drilling equipment, such as hydraulic hammer equipment, which can be used with the two main types of boom may be used with the boom of the invention. Holes may be drilled at any position achievable by conventional booms and in addition parallel holes may readily be drilled even in a circular pattern.

Reference is made to the drawing, which shows a mining drill boom according to one embodiment of the invention.

The boom comprises a base plate 1 rotatably mounted by means of a gear drive 2, which may be mounted on a suitable wheeled or tracked vehicle. A main support arm 3 is mounted at one end of the base plate by means of a universal mounting 4 which has two mutually perpendicular pivot pins 5 and 6. At the other end of the support arm 3 a similar universal mounting 7 connects the arm 3 to a carriage-mounting plate 8. Two subsidiary arms 9, of the same length as the main support arm 3, are connected to the base plate and to the carriagemounting plate 8 by means of universal mountings 10 of similar design to those 4 and 7 of the support arm 3. The arms are arranged with the axes passing through their respective mountings parallel.

A drill carriage 11 is mounted on the carriagemounting plate 8 by means of a first pivot 12, arranged to permit pivoting of the carriage in a vertical plane when the boom is in the position shown in the drawing, and a second pivot 13, permitting rotation in a horizontal plane with the boom in the position shown. The carriage 11 has two main parts, a fixed part 14 and a sliding part 15 which may slide in guides 16 mounted on the fixed part, permitting sliding part 15 of the carriage 11 to be advanced towards a face to be drilled. A drill motor 17 is slidably mounted on the sliding part 15, the drill (not shown) passing, in use, through a guide plate 18 at the end of the carriage. The guide plate 18 carries a short probe 19 to assist in location of the carriage against the face to be drilled.

A hydraulic slew ram 20 is mounted on the base plate 1 by means of a universal mounting 21, the other end of the ram being pivotally connected to the side of the main support arm 3. Extension or retraction of this slew ram 20 slews the boom to the left or right relative to the orientation shown in the drawing. A hydraulic lift ram 22 is similarly connected between the base plate 1 and the underside of the main arm 3, and extension or retraction of this lift ram 22 raises or lowers the boom in the position shown.

Vertical pivoting of the carriage 11 relative to the carriage-mounting plate 8 is achieved by means of a pivoted hydraulic carriage lift ram 23, which extends forwardly of the boom. Rotation or slewing of the carriage relative to the mounting plate 8, and hence to the boom, is achieved by means of a pivotallymounted carriage slew ram 24 which extends between the fixed part 14 of the carriage 11 and the side of the second pivot 13. A crowd ram 25 extends from the fixed part 14to a pivotal mounting 26 on the end of the sliding part 15 of the carriage.

Retraction of the crowd ram 25 advances or "crowds" the sliding part towards the face.

The five hydraulic rams 20, 22, 23, 24 and 25 and the gear drive 2 give rise to six of the seven movements provided for in the "universal" type of boom, whilst the automatic parallelism provided for by the use of the three arms 3 and 9 enables holes to be drilled parallel to any chosen axis. Location of the rotation gear drive 2 at the base plate 1 rather than at the carriage-support plate 8 reduces the weight on the arm, permitting a heavier and more powerful drilling action to be used. Since the whole boom is rotated, as with the pantograph type of boom, a circular pattern or parallel holes may readily be drilled without the need to carry out a large number of accurately and individually controlled movements to align the drill for each hole.

Claims

1. A mining drill boom comprising a base plate and a drill carriage-mounting plate linked thereto by means of three elongate members universally coupled to each plate in the same triangular configuration whereby the plates remain substantially parallel one to the other during relative displacement thereof, the base plate being rotatably mounted about an axis substantially normal to the base plate.

2. A drill boom according to Claim 1, wherein a drill carriage is pivotally mounted on the carriagemounting plate so as to allow rotation of the carriage in at least one of the two planes perpendicular to the surface of the carriage-mounting plate.

3. A drill boom according to Claim 1 or 2, wherein the carriafe is slidably mounted relative to the carriage-mounting plate.

4. A drill boom according to Claim 1, 2 or 3, wherein one of the three elongate members is a main load-bearing arm and the other two members are subsidiary control arms.

5. A drill boom according to Claim 4, wherein two hydraulic lifting rams are mounted between the base plate and the main arm, one of the rams causing movement of the arm in a plane perpendicu lartothat in which the arm is moved by the other ram.

6. A drill boom according to any preceding claim, wherein the base plate is rotated by a hydraulic motor via a reduction gearbox.

7. A drill boom according to any preceding claim, wherein the base plate is carried by a wheeled or tracked vehicle.

8. A mining drill boom, substantially as described with reference to the drawing.