GB2041424A - Excavating machines for excavating rock or mineral - Google Patents

Abstract

An excavating machine for excavating rock or mineral to extend an underground roadway or tunnel comprises a floor mounted base (1), a support assembly (2) mounted on the base, and a cutter-carrying boom (3) pivotally mounted on the support assembly, the support assembly comprising a turret (4) providing a rotary bearing assembly (6) for a shaft (7) extending substantially longitudinally of the roadway or tunnel, a rotary drive mechanism (9) being provided at one end of the shaft and a boom support assembly (13) being provided at the other end of the shaft, the boom support assembly comprising two mutually transverse pivotal mountings (16, 18) for the boom. <IMAGE>

Description

SPECIFICATION Excavating machines for excavating rock or mineral This invention relates to excavating machines for excavating rock or mineral to extend an underground roadway or tunnel.

In particular the present invention relates to an excavating machine comprising a base movable along the roadway or tunnel floor, a support assembly mounted on the base and a forwardly directed cutter carrying boom pivotally mounted on the support assembly.

Such a prior known excavating machine includes a horizontal slewing ring between the base and the support assembly enabling the boom to swing about a generally vertical axis under the action of hydraulic ram means.

Unfortunately, the intricate construction of the slewing ring tends to be relatively easily damaged by the cutting thrusts generated when relatively hard rock or mineral is being excavated. Consequently, in hard rock or mineral cutting conditions the slewing ring tends to have a relatively short operational life.

An object of the present invention is to provide an excavating machine which does not require a slewing ring and which thereby tends to overcome the above mentioned disadvantage.

According to the present invention an excavating machine for excavating rock or mineral to extend an underground roadway or tunnel comprises a base moveable along the roadway or tunnel floor, a support assembly mounted on the base, and a cutter-carrying boom pivotally mounted on the support assembly, the support assembly comprising a turret mounted on the base and providing a rotary bearing assembly for a shaft which, in use, extends substantially longitudinally along the roadway or tunnel, a rotary drive mechanism being provided at one end of the shaft and a boom support assembly being provided at the other end of the shaft, the boom support assembly comprising two mutually transverse pivotal mountings for the boom.

Conveniently, hydraulic ram means are provided for moving the boom about the two mutually transverse pivotal mountings.

Preferably, one of the hydraulic ram means is mounted between the rotary drive mechanism and the boom support assembly.

Advantageously, the rotary drive mechanism and the boom support assembly are connected by brace means external to the turret.

Preferably, one of the hydraulic ram means is mounted between the boom support assembly and the brace means.

Preferably, the turret is fixedly mounted on the base.

By way of example only, one embodiment of the present invention is described with reference to the accompanying drawings in which: Figure 1 is a side elevation of an excavating machine constructed in accordance with the present invention, the machine being shown in one operational position; Figure 2 is an incomplete plan of Fig. 1; Figure 3 is a side elevation of the excavating machine of Fig. 1, the machine being shown in an alternative operational position; Figure 4 is an incomplete plan of Fig. 3; and Figure 5 is an incomplete front view of Fig.

1.

The drawings show an excavating machine for excavating rock or mineral from a working face to extend an underground roadway or tunnel, to comprise a floor mounted base 1 arranged to slide along the roadway or tunnel floor towards the working face as the roadway or tunnel is extended, the base comprising two parts relatively movable under the action of hydraulic rams (not shown).

A support assembly 2 for a forwardly directed cutter-carrying boom 3 is mounted on the base 1, the support assembly comprising a turret 4 which is fixedly mounted on the base and which provides a rotary bearing assembly 6 for a shaft 7 which extends substantially longitudinally along the roadway or tunnel and the rear end of which is drivably engaged by a rotary drive mechanism 9 as described in detail in our co-pending prior British patent application No. 43098/78.The rotary drive mechanism 9 comprises two hydraulic rams 10 the cylinders of which are pivotally mounted on the base and the piston rods of which are pivotally connected to a slide member 11 pivotally mounted on the base and including a third hydraulic ram (not shown) arranged to urge a slide eiement to and fro along a slideway provided by the slide member 11, the slide element being drivably connected to a crank lever arranged to rotate the shaft 7 through one hundred and eighty degrees upon actuation of the rams which are double acting so the shaft can be rotated first one hundred and eighty degrees in one direction and then one hundred and eighty degrees in the opposite direction. As explained in the co-pending application the three ram arrangement gives a substantially constant rotating force on the shaft throughout the full extent of rotational movement.

A boom support assembly 1 3 for the cutter carrying boom 3 is fixedly mounted on the front end of the shaft 7, the boom support assembly 1 3 comprising a first component 14 fixed to the shaft 7 and connected to a second component 1 5 via a pivotal mounting 1 6. The second component 1 5 is forked (as seen in Fig. 2) to provide a pivotal mounting 1 8 for the cutter-carrying boom 3, the pivotal axes of the two pivotal mountings 1 6 and 1 8 being arranged transverse to each other.The cutter-carrying boom 3 comprises a drive motor housing 20 provided with stub shafts 21 for engaging the pivotal mounting 18, and a rotary cutter 22 driven around the longitudinal axis 23 of the boom by the drive motor within housing 20. Movement of the boom about the two pivotal mountings 1 6 and 18 is controlled by the action of pairs of hydraulic rams 25 and 26, respectively. The pair of rams 25 are connected between the second component 1 5 and a brace member 28 secured rigidly between the rotary drive mechanism 9 and the first component 14, and the pair of rams 26 are connected between the second component 1 5 and the boom 3.

A loading apron 30 having reciprocating arms 31 (not shown in Fig. 2) is mounted on the base 1 beneath the boom 3, in use the reciprocating arms urging cut mineral or rock from the roadway or tunnel floor towards a conveyor (not shown) extending longitudinally through the base.

In operation, the excavating machine is located adjacent to the working face to be excavated by the cutter 22 to extend the underground roadway or tunnel. The base 1 is advanced with the boom 3 horizontal until the cutter 22 is sumped fully into the working face. The rams 25 are actuated to move the cutter sideways from the central position by a distance substantially equal to the cutter diameter. The rotary drive mechanism 9 is actuated to rotate the shaft 7 through one hundred and eighty degrees so that the cutter passes over the central position and finished up on the opposite side of the central position and displaced from the central position by a distance substantially equal to the cutter diameter.The rams 25 are actuated again to move the cutter sideways by a distance substantially equal to the cutter diameter, the cutter at this stage being displaced from the central position by a distance substantially equal to twice the cutter diameter. The rotary drive mechanism 9 is re-actuated to rotate the shaft 7 one hundred and eighty degrees in the opposite direction so that the cutter once again passes over the central position and finished up horizontally displaced from the central position by a distance substantially equal to twice the cutter diameter. The cutter then is moved sideways until the cutter is substantially three times the cutter diameter from the central position and the arcing procedure repeated. The whole of the above outline cutting procedure is repeated until the whole of the upper portion of the working face has been excavated.Such a cutting procedure ensures that a smooth outer cut profile is obtained enabling a good engagement between the outer exposed rock or mineral surface and roof supports which are installed along the roadway or tunnel.

The lower portion of the working face then is excavated by lowering the cutter 22 from the boom horizontal position by actuation of the rams 26, the cutter being lowered by a distance substantially equal to the cutter diameter. The rams 25 then are actuated to sweep the cutter from a position adjacent to the outer periphery of the working face towards a position directly beneath the central cutter position. The rotary drive mechanism 9 then is actuated to rotate the shaft 7 and boom 3 through one hundred and eighty degrees, the rams 26 then being re-activated to move the cutter back to a position directly beneath the central position. The ram 25 then are re-activated to move the cutter towards the opposite outer cut profile to complete the sweep across the working face.The cutter is lowered by a further increment substantially equal to the cutter diameter until the cutter is finally swept to cut the roadway or tunnel floor.

Upon completion of the excavation of the working face roof supports (indicated by 'I' section beams 35 in Fig. 2) are installed around the curved outer cut profile and the base 1 advanced towards the newly exposed working face until the cutter is sumped fully into the working face. The whole of the above outlined cutting procedure then is repeated to further extend the roadways or tunnel.

Throughout the cutting procedure the cutter is rotated continuously about the longitudinal axis of the boom by the drive motor housed within the boom housing 20. In addition the loading arms 31 are reciprocated continuously to load the cut rock or mineral onto the conveyor extending longitudinally through the base which convey the cut rock or mineral towards further conveyor means (not shown) which conveys the cut material along the roadway or tunnel away from the working face.

From the above description it will be appreciated that the excavating machine constructed in accordance with the described embodiment of invention is simple and robust.

The need for a slewing ring is eliminated and replaced by arcing mechanism including a relatively large diameter, 'relatively long bearing. The base and support assembly frames are of substantial construction. The turret is stationary mounted on the base.

In addition an accurate arch roof support outer profile is cut enabling good engagement with the roadway or tunnel roof supports.

Further a substantially flat floor is formed which if desired can be raised or lowered to vertically steer the machine.

In other embodiments of excavating machine the rotary cutter is mounted for rotation about an axis extending transverse to the longitudinal axis of the boom.

In still further embodiments the pair of rams 25 are connected between the rotary drive mechanism and the boom support assembly.

Claims (11)

1. An excavating machine for excavating rock or mineral to extend an underground roadway or tunnel, comprising a base moveable along the roadway or tunnel floor, a support assembly mounted on the base, and a cutter-carrying boom pivotally mounted on the support assembly, the support assembly comprising a turret mounted on the base and providing a rotary bearing assembly for a shaft which, in use, extends substantially longitudinally along the roadway or tunnel, a rotary drive mechanism being provided at one end of the shaft and a boom support assembly being provided at the other end of the shaft, the boom support assembly comprising two mutually transverse pivotal mountings for the boom.

2. An excavating machine as claimed in claim 1, comprising hydraulic ram means for moving the boom about the two mutually transverse pivotal mountings.

3. An excavating machine as claimed in claim 2, in which one of the hydraulic ram means is mounted between the rotary drive mechanism and the boom support assembly.

4. An excavating machine as claimed in claim 1 or 2, in which the rotary drive mechanism and the boom support assembly are connected by brace means external to the turret.

5. An excavating machine as claimed in claim 4 when dependent upon claim 2, in which one of the hydraulic ram means is mounted between the boom support assembly and the brace means.

6. An excavating machine as claimed in any one of the preceding claims, in which the turret is fixedly mounted on the base.

7. An excavating machine as claimed in any one of the preceding claims, comprising loading means mounted on the base.

8. An excavating machine as claimed in any one of the preceding claims, comprising a rotary cutter mounted on the boom.

9. An excavating machine as claimed in claim 8, in which drive means for the rotary cutter-are mounted on the boom.

10. An excavating machine as claimed in claim 8 or 9, in which the rotary cutter is arranged to rotate about an axis extending longitudinally of the boom.

11. An excavating machine as claimed in claim 8 or 9, in which the rotary cutter is arranged to rotate about an axis extending transverse to the longitudinally axis of the boom.

1 2. An excavating machine for excavating rock or mineral to extend on underground roadway or tunnel, substantially as described with reference to the accompanying drawings.