WO2003044321A1

WO2003044321A1 - Rock prying apparatus for hanging roof in mines

Info

Publication number: WO2003044321A1
Application number: PCT/IB2002/004879
Authority: WO
Inventors: Nicolaas Daniel Lombard Burger; Adam Jacobus Von Wielligh; Rudolf Werner Ottermann
Original assignee: Nicolaas Daniel Lombard Burger; Adam Jacobus Von Wielligh; Rudolf Werner Ottermann
Priority date: 2001-11-22
Filing date: 2002-11-22
Publication date: 2003-05-30
Also published as: ZA200403542B; AU2002347478A1

Abstract

The invention concerns a rock prying apparatus (10) which includes a rod (12) having an operating end carrying an hydraulically or pneumatically actuated prying mechanism (40). The mechanism (40) is actuable, when supplied with hydraulic or pneumatic fluid under pressure, to pry rock fragments free of a wall in a mine working. This is achieved by working a tip of the mechanism into a crack in the wall and actuating the mechanism to cause jaws (40.1, 40.2) to open. The preferred embodiment has a manually operated hydraulic pump (16) for supplying hydraulic or pneumatic fluid under pressure to the prying mechanism (40) to cause the jaws to open.

Description

ROCK PRYING APPARATUS FOR HANGING ROOF IN MINES

BACKGROUND TO THE INVENTION

THIS invention relates to a rock prying apparatus.

Blasting in underground mines frequently causes fracturing of the rock mass in the hanging wall close to the mining face. This gives rise to the possibility of a localised rockfall and resultant injury to workers in the vicinity. It is accordingly necessary after a blast to make the face area safe before workers can commence cleaning operations. This is achieved inter alia by removing loose rock fragments from the hanging wall using a pry bar. Conventional pry bars consist of a steel bar, typically with a relatively sharp prying formation at its end. In use, the prying formation is wedged into exposed cracks in the rock mass and the bar is manipulated to pry the associated loose rock fragment free of the hanging wall.

The conventional operation is however itself extremely dangerous for the operator of the pry bar who is obliged to stand virtually beneath the loose rock fragment in order to achieve the desired result. SUMMARY OF THE INVENTION

According to the invention there is provided a rock prying apparatus comprising a rod having an operating end carrying an hydraulically or pneumatically actuated prying mechanism which is actuable, when supplied with hydraulic or pneumatic fluid under pressure, to pry rock fragments free of a wall in a mine working.

The apparatus may include an hydraulic or pneumatic pump for supplying the hydraulic or pneumatic fluid under pressure. This may, for instance, be hand or foot operated or it may be operated by a mechanical, hydraulic or pneumatic drive. In a preferred version of the invention the rod includes a handle where it can be gripped manually by an operator and there is an hydraulic pump which is mounted on the rod and actuable by hand to pump hydraulic fluid to the prying mechanism to actuate it. Conveniently the hydraulic pump is lever actuated and operates in a closed circuit. The rod may be hinged at a position between the handle and the operating end, typically at a position towards the operating end.

The apparatus of the invention may also include a hammer mechanism to urge a tip of the prying mechanism into exposed cracks prior to actuation thereof. This mechanism may include a weight arranged slidably on a portion of the rod and an anvil fixed to that portion, the weight being slidable forcibly against the anvil. Most preferably, the hammer mechanism is remotely operable from the handle of the rod.

The prying mechanism may comprise a pair of jaws pivoted to one another and extending to free ends at which they form a sharp tip, and hydraulically or pneumatically operated means for urging the jaws pivotally apart from one another to apply a prying action to a rock mass when the tip is inserted into a crack in that mass.

Other features of the invention are described in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a side view of a rock prying apparatus according to this invention;

Figure 2 shows a detail of a part of the apparatus of Figure 1 ;

Figure 3 diagrammaticaliy illustrates the rock prying apparatus in use;

Figure 4 shows a diagrammatic elevation of a preferred embodiment;

Figure 5 shows a diagrammatic cross-section of a portion of the embodiment of Figure 4; and

Figure 6 shows a perspective view of the prying mechanism of the embodiment seen in Figures 4 and 5.

DESCRIPTION OF EMBODIMENTS

Figure 1 shows a rock prying apparatus 10 according to one embodiment of this invention. The apparatus includes a rod 12 having a handle 14 at one end. The rod also includes an hydraulic reservoir 15, an hydraulic pump 16 having an actuating handle 18, a telescopic section 20 composed of inner and outer elongate, hollow members 20.1 and 20.2 respectively, a hinge mechanism 22 and a further hollow, elongate member 24 to which is fixed a flange 26 acting as an anvil as described below. The hydraulic reservoir 15 is located inside the handle 14 adjacent the pump 16. The hollow member 20.1 can be telescoped into or out of the hollow member 20.2 and is formed with a series of axially spaced, diametrically extending holes 28. The member 20.1 is formed with a corresponding, diametrically extending hole which can be aligned with a selected one of the holes 28, the desired length of the rod 12 being set by engagement of a transverse pin 30 in the aligned holes.

The hinge mechanism 22 includes discs 32 attached respectively to the members 20.1 and 24. The discs carry opposing, radially oriented teeth which can engage one another at any one of a variety of angular positions of the member 24 relative to the member 20.1. Once a desired angular setting has been achieved, the discs are drawn together and are locked relative to one another by a transverse bolt 34.

Mounted slidably on the member 24 is a tubular weight 36. The weight can be slid back in the direction of the arrow 38 and then slid forcibly in the opposite, forward direction to apply a sharp hammer blow to the flange 26. The advantage of this action is described below.

Mounted at the end of the member 24 is a prying mechanism 40. This comprises a pair of jaws 40.1 , 40.2 which are pivoted to one another at a pivot axis 42. Located between the jaws is an hydraulic actuator (not visible in Figure 1) which can be extended by a supply of pressurised hydraulic fluid to force the jaws apart from one another. A coil spring (also not visible in Figure 1) acts between the jaws and biases them towards one another. The jaws 40.1 , 40.2 extend to a relatively sharp tip 43.

The hydraulic actuator mentioned above as well as the pump 16 and reservoir 15 form part of a closed hydraulic circuit. This circuit also includes appropriate conduits (not visible in Figure 1) which extend from the pump through the members 20.1 , 20.1 , past the hinge mechanism 22 and through the member 24 to the hydraulic actuator. Figure 3 illustrates the apparatus 10 in use and shows an operator 42 standing in a mine working 44 in the vicinity of the mining face 46, after a blast has taken place. The operator's task is to remove potentially loose rock fragments, defined by cracks 48, from the hanging wall 50 of the working. To achieve this, he manoeuvres the handle 14 to work the tip 43 of the prying mechanism 40 into a crack 48. For safety reasons this action is carried out from a position as far as possible from the site of the loose rock. The operator initially sets the length of the rod 12 to a desired value by telescoping the members 20.1 , 20.2 to the appropriate position relative to one another and locks them at that position using the pin 30.

He also sets the member 24 at the appropriate angular orientation relative to the member 20.1 , to give best access to the crack, by manipulating the hinge mechanism 22.

To assist him in carrying the weight of the apparatus, the handle end can be supported in a belt-mounted bucket or pot 52 of the kind used by fishermen to support the end of a fishing rod.

The operator works the tip 43 into the crack 48 as far as he can. To assist him in this exercise he can use the hammer mechanism constituted by the weight 36 and flange or anvil 26 to apply one or more impact blows in a direction to knock the tip 43 into the crack.

Once the tip has been inserted into a crack by an appropriate distance, the operator pumps hydraulic fluid to the hydraulic actuator by pivoting the lever 18 back and forth, as illustrated in broken outline in Figure 1. The jaws 40.1 , 40.2 are driven apart from one another by the actuator against the bias of the aforementioned coil spring, and pry open the crack 48. This action may alone be sufficient to pry open the crack far enough to loosen the rock fragment, so that it falls under gravity to the footwall or floor. If the action is not sufficient, the process is repeated in other cracks until the rock fragment has been dislodged. It will be understood that a major benefit of the apparatus is the fact that the operator can stand well away from the danger zone immediately beneath rocks which are dislodged. The hammer mechanism may also be remotely operated, for instance with the aid of the pulley mechanism seen in broken outline in Figure 1. A cord 60 having is ends tied to opposite ends of the weight 36 is entrained around pulleys 62, 64, 66 and 68. With this arrangement it will be appreciated that the operator can cause the weight to move in one direction or the other by pulling appropriately on the cord at his remote position.

When a rock prying operation has been completed a valve (not shown) in the hydraulic circuit is opened to relieve the pressure in the circuit and allow the spring to bias the jaws 40.1 , 40.2 towards one another again with hydraulic fluid being driven from the actuator back to the reservoir 15.

The embodiment seen in Figures 4 to 6 is similar in many respects to that seen in the earlier Figures, and like components are indicated by like numerals. Features not specifically referred to may be taken as similar to those described above.

In the embodiment of Figures 4 to 6, the rod 20 is of fixed length, i.e. is not telescopic as in the earlier embodiment. Figure 5 shows a portion of the hydraulic supply line 70 leading from the pump 16 (not shown in Figures 4 to 6) which is, as before, operated by appropriate pivotal movement of the lever 18. The line 70 leads into a cylinder 72 in which a piston 74 can reciprocate. An end 76 of the piston projects from the cylinder as shown.

Figure 6 illustrates a modified prying mechanism 40 used in the second embodiment. The mechanism 40 has jaws corresponding to those of the first embodiment. However in this case one of the jaws, indicated by the numeral 40.2, is fork-shaped with spaced apart, chisel-shaped prongs 78. The other jaw, indicated by the numeral 40.1 , has a single, chisel-shaped prong 80 which fits between the prongs 78 when the mechanism is in a closed condition. Because the prongs effectively intercalate with one another, rather than merely lying alongside one another in the closed condition, the mechanism of Figure 6 is somewhat narrower than that of the earlier embodiment and is able to enter somewhat narrower cracks during rock prying operations.

The prongs 78 and 80 are pivoted to one another at an axis 82 and the prong 80 has a shoulder 84 aligned with the projecting end 76 of the piston. Accordingly, when hydraulic fluid is pumped into the cylinder 72 by manipulation of the lever 18, the piston 74 is driven out of the cylinder with the result that the end 76 presses on the shoulder 84 and causes the prong 80 to pivot to an open condition relative to the jaws 78, as shown in Figures 4 to 6. As in the first embodiment, a spring (not shown) may be provided to return the prongs to the closed condition after a rock prying operation has been completed.

The embodiment of Figures 4 to 6 also includes a tubular weight 36 which in this case is impacted on the rear end of the cylinder 72 to assist in working the tip of the prying mechanism 40 into a crack.

In both embodiments described above, the rod 20 and/or member 24 could be made of steel, a plastics composite material such as GRP (glass reinforced plastic), or other suitable materials. GRP will generally be preferred because it is lighter and will accordingly reduce the overall weight of the overall apparatus 10 and make it easier to manhandle in use.

The embodiments described above are manually operated. The invention also envisages embodiments in which an hydraulic power pack is provided separately from the handle. The power pack may include a foot-operated pump and, as in the embodiment above, may operate in a closed circuit. Yet another possibility is for the apparatus to be mounted on an underground mining machine, such as a continuous mining machine, with the necessary hydraulic pressure being supplied by hydraulic equipment on the machine itself. Still further the invention envisages arrangements in which the prying mechanism is actuated by pneumatic as opposed to hydraulic pressure. In such versions of the invention, the normal compressed air supply system operating in the mine could be used to supply the pneumatic pressure to actuate the prying mechanism. In general, the invention contemplates alternatives making use of an external mechanically, hydraulically or pneumatically powered source of pressurised fluid.

Claims

1.

A rock prying apparatus comprising a rod having an operating end carrying an hydraulically or pneumatically actuated prying mechanism which is actuable, when supplied with hydraulic or pneumatic fluid under pressure, to pry rock fragments free of a wall in a mine working.

2.

An apparatus according to claim 1 comprising a pump for supplying the hydraulic or pneumatic fluid under pressure to the prying mechanism.

3.

An apparatus according to claim 2 wherein the pump is hand or foot operated.

4.

An apparatus according to claim 3 wherein the rod includes a handle which can be gripped manually by an operator and which carries an hydraulic pump actuable by hand to pump hydraulic fluid to the prying mechanism to actuate it.

5.

An apparatus according to claim 4 wherein the rod is hinged at a position between the handle and the operating end.

6.

An apparatus according to claim 4 or claim 5 wherein the hydraulic pump is lever actuated and operates in a closed circuit.

7.

An apparatus according to claim 6 comprising a pump-actuating lever pivoted to the rod.

8.

An apparatus according to any one of claims 2 to 7 wherein the prying mechanism comprises jaws which are pivoted to one another and extend to free ends at which they form a tip, and an hydraulic actuator operative, when supplied with hydraulic fluid under pressure by the hydraulic pump, to urge the jaws pivotally apart from one another to apply a prying action to a rock mass when the tip is inserted into a crack in that mass.

9.

An apparatus according to claim 8 comprising a first jaw having spaced prongs and a second jaw having a prong arranged to intercalate with the prongs of the first jaw.

10.

An apparatus according to claim 9 wherein the hydraulic actuator comprises an hydraulic cylinder in which a piston is reciprocable, a portion of the piston projecting from the cylinder to act against the prong of the second jaw and cause it to pivot relative to the prongs of the first jaw. An apparatus according to any one of the preceding claims comprising a hammer mechanism operable to urge a tip of the prying mechanism into exposed cracks prior to actuation thereof.

12.

An apparatus according to claim 11 wherein the hammer mechanism includes a weight arranged slidably on a portion of the rod and an anvil fixed to that portion, the weight being slidable forcibly against the anvil.

13.

An apparatus according to claim 10 comprising a hammer mechanism operable to urge a tip of the prying mechanism into exposed cracks prior to actuation thereof.

14.

An apparatus according to claim 13 wherein the hammer mechanism includes a weight arranged to slide on a portion of the rod and to be impacted against the cylinder of the hydraulic actuator.