GB2145134A

GB2145134A - Circular heading machine

Info

Publication number: GB2145134A
Application number: GB08322467A
Authority: GB
Inventors: Arthur Gill
Original assignee: Anderson Strathclyde PLC
Current assignee: Anderson Strathclyde PLC
Priority date: 1983-08-20
Filing date: 1983-08-20
Publication date: 1985-03-20
Also published as: IT8467821A1; WO1985001081A1; GB8322467D0; MX160500A; IT1179051B; ZA846294B; EP0153935B1; AU570725B2; IN161662B; AU3310684A; ES8505761A1; IT8467821A0; BR8407052A; DE3468480D1; ES535264A0; GB2145134B; JPS61500673A; CA1235150A; EP0153935A1

Abstract

Circular heading machines for excavating tunnels by advancing a machine in step-wise fashion and erecting tunnel supports. The circular heading machine has an elongate machine body (10) at the forward end of which a forwardly directed cutter boom (11) is mounted, rams advance the machine body in step-wise fashion acting against grippers (23) and a profile ring (18, 18') limits peripheral movement of the cutter boom to form an accurate profile. A gathering apron (16) is provided at the forward extremity of the machine body. The cutter boom (10) is mounted on a sliding carriage (12) longitudinally movable on and independently of the machine body and a hood (17) overlies the apron. A cage structure (21) extends rearwardly from the hood structure and surrounds the boom cutter (11) and sliding carriage (12) and tunnel support erecting means (20) are provided externally of the cage structure, directly behind the hood structure. Thus the tunnel support structures are erected over the machine body rather than behind the machine, and also erection of the tunnel support structures takes place simultaneously with operation of the cutter. The hood (17) is a semi-circular member supported by hydraulic rams (17A) for height adjustment.

Description

SPECIFICATION Circular Heading Machine This invention relates to circular heading machines for excavating tunnels.

An object of the invention is to provide a machine with an economical advance rate, by virtue of carrying out cutting and tunnel support operations simultaneously.

According to the present invention there is provided a circular heading machine comprising an elongate machine body having at its forward end a forwardly directed cutter boom mounted on a sliding carriage longitudinally moveable on and independently of the machine body, a profile collar on the boom and a transversely disposed profile guidance ring on the machine body to limit peripheral movement of the cutter boom, a gathering apron at the foward extremity of the machine body and a semi-circular hood overlying the apron, a cage structure extending rearwardly from the apron/hood structure surrounding the boom cutter and sliding carriage and means externally of the cage structure for erecting tunnel support structures directly behind the apron/hood structure.

Preferably, the machine body carries thrust means connected to a radial gripper means which when extended to engage a tunnel wall enables the thrust means to move the machine body relative thereto, said gripper means when retracted being moveable longitudinally on the machine body.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a side elevation of a circular heading machine according to the invention; Fig. 2 is a plan view of Fig. 1; Figs. 3 to 5 are side elevations of the machine illustrating, with Fig. 1 , the cycle of operation; Fig. 6 is a rear elevation of the lines VI--VI of Fig. 1 showing tunnel support erection apparatus; Fig. 7 is a detail illustrating lagging between the tunnel supports; and Fig. 8 is a detail illustrating a trailing arm.

The circular heading machine has an elongate body 10 which mounts a cutter boom 11 at its forward end, the boom 11 being carried on a sliding carriage 12 which is slidably moveable on the machine body 10 by thrust jacks 13. The cutter boom 11 carries a conical cutter head 14, by which a tunnel 1 5 can be excavated; by tilting jacks 1 A and slewing jacks 11 B.

At the forward extremity of the machine body there is a semi-circular gathering apron 1 6 which carries windmill or gathering arms (not shown) and above the apron there is a semi-circular hood 1 7; this hood may be a light section stone/dust guard as illustrated in Fig. 1 comprising a number of plates or a more solid member for temporary support and it may be provided with trailing fingers (Fig. 8) as hereinafter described.

The apron and hood converge rearwards and terminate in a profile guidance ring 1 8 and on the cutter boom there is a profile collar 18' which can run round the inner face of the ring 18 thus limiting the movement of the boom.

Immediately behind the apron/hood structure is a tunnel-support mechanical erection apparatus 20 by which ring girders can be erected as hereinafter described with reference to Fig. 6 or alternatively concrete segmental rings.

A cage structure 21 is provided on the machine body to enclose the boom 11 and carriage 12 and the support erection apparatus 20 is external of the cage 21. Tunnel support erectors can therefore work in safety on a platform 22 on the machine body while the cutter 14 is in operation.

Towards the rear of the machine body 10, a radial gripper mechanism 23 is provided having four segmental grippers 24 which are radially extendible to engage the sides, roof and floor of the excavated tunnel. Thrust jacks 25 are connected between the lowermost gripper 24 and an underframe 26 on the machine body 10. When the grippers 24 are firm against the tunnel, the jacks 25 can extend to push the machine body forward; when the grippers are retracted the jacks 25 can be retracted to draw the gripper mechanism 23 forward.

Rearward of the gripper mechanism a segmental support leg 27 is mounted on the machine body 10 and is extended downwards to engage the tunnel floor only when the gripper mechanism is retracted, thus to hold the machine in its existing alignment. The machine body carries an integral scraper chain conveyor section 30 which runs from the gathering apron, under the machine body then upwardly towards the rear end, exiting in a rearward extension 31 beyond the machine body for transfer of excavated minerals to a bridge conveyor 32 trailed by the machine. The bridge conveyor can be set to allow the scraper conveyor to create an infill 33 behind it. Alternatively, it can be aligned below conveyor extension 31. The machine operates in cycles as illustrated in Figs. 1 and 3 to 5.

To begin the cycle, as illustrated in Fig. 3 the rear support leg 27 is lowered, the gripper mechanism 23 is retracted (chain lines) and drawn forward by retraction of the thrust jacks 25. The cutter boom carriage 12 is in its retracted position with the cutter 14 just clear of the mineral face 35.

The side grippers 24 are extended to engage the side walls of the tunnel and the rear support leg 27 is retracted. The side grippers are then adjusted to align the machine horizontally.

The upper and lower grippers 24 are then extended to engage the roof and floor and the side grippers are retracted, this allows adjustment of the upper and lower grippers to align the machine vertically. If the ground is weak the side grippers are extended again to grip the sides so that the pressure on the lower gripper can be reduced.

The machine is now ready to cut into the mineral face 35.

The cutter boom carriage is advanced to sumpin the cutter head and excavate to a depth of 0.5 metre (Fig. 1). The head can move universally within the limits set by the profile ring 1 8 and forms a circular hole slightly in excess of the required tunnel diameter with a new mineral face 35A.

After that excavation the cutter boom carriage is retracted and the machine advanced 0.5 metre to once again locate the cutter head against the mineral face now 35A. The carriage is then advanced again (Fig. 4) to sump-in and excavate another 0.5 metre to form a new mineral face 35B.

After that excavation the carriage is retracted and the machine advanced a further 0.5 metre (Fig. 5) to begin a new cycle.

The cycle is then repeated.

At the time of advancing the machine its first 0.5 metre, tunnel support erection is carried out by erectors working on the platform 22 situated immediately behind the apron/hood structure.

Segments of ring girders 40 (Figs. 1 and 6) are delivered, e.g. by monorail 41 to the rear of the machine and drawn over a pair of longitudinal rails 42 overlying the machine body 10 by means of a winch 43 on the cage structure 21. At the erection area directly behind the apron/hood the segments 40 are mounted in turn on the mechanical erector 20 in the form of a circular chain 44 (Fig. 6) jointed and hauled round the tunnel perimeter until a complete but coilapsed ring has been built. Over the top half section lagging in the form of wire mesh panels 45 is introduced between the last panel of lagging and the new collapsed ring girder, see Fig. 7.

When the machine has advanced to its second, final 0.5 metre the ring girder is expanded by raising an arcuate ring support 46 via two hyraulic rams to trap the lagging 45 and meet the perimeter of the tunnel. A ring expansion joint (not shown) is then fitted and to give extra tunnel support the machine is designed to allow this expansion joint to be located in different positions on adjacent ring girders so that the weakest point in the girder is not always in the same relative position.

In an alternative hood construction, Fig. 8, rearwardly extending fingers 47 are resiliently connected to the front edge of each hood plate 1 7 and extend back by such a length that they overlie not only the ring girder being erected but also the last fully erected ring girder. When the machine reaches the end of its cycle, the ring support 46 is extended to expand the ring girder being erected and during the new cycle when the machine is pushed forward the trailing fingers are drawn clear of the previously last erected ring girder to overlie the new last erected ring girder.

Dust extraction ducts 50 are formed in the machine body whereby when air is blown into the tunnel and over the machine dust from the excavation will be drawn through the ventilation ducts 50 to exit from the rear into a dust collection unit (not shown) thus enabling the erectors to operate in a relatively dust free atmosphere.

A hydraulic power pack 51 can be trailed behind the machine or, as illustrated in Fig. 1 located under the machine body and is used to power all the machine's functions.

In the preferred embodiment four radial grippers 24 are provided, but the two side grippers plus the rear support leg 27 may be sufficient; the side grippers would permit alignment in the horizontal plane and the rear leg alignment in the vertical piane. The thrust jacks in this arrangement are connected to one or both side grippers.

In another alternative arrangement, three grippers spaced at 1 20C may form the gripper means.

An advantage of the circular heading machine as hereinbefore described is its economic rate of advanced, cutting 1 metre in each cycle in two cuts of 0.5 metre, while simultaneously allowing support erection operations to be carried out in safety.

Another advantage, due to the feature of the boom carriage being moveable independently of the machine, is that in the event of sudden convergence trapping the machine against further forward movement, the cutter can be advanced to cut a chamber and the mineral cut thereby can then be removed by hand by personnel gaining access to the mineral through the cage and apron/hood.

Claims

1. A circular heading machine comprising an elongate machine body having at its forward end a forwardly directed cutter boom mounted on a sliding carriage longitudinally moveable on and independently of the machine body, means to advance the machine body in step-wise fashion, means to limit peripheral movement of the cutter boom to form an accurate profile, and a gathering apron at the forward extremity of the machine body, the cutter boom is mounted, a hood structure overlying the apron, a cage structure extending rearwardly from the hood structure surrounding the boom cutter and sliding carriage and means provided externally of the cage structure directly behind the hood structure for erecting circular tunnel support structures over the machine body, erection of the tunnel support structures taking place simultaneously with operation of the cutter.

2. A machine according to claim 1, in which the hood structure comprises a semi-circular hood supported by hydraulic jacks for height adjustment of the hood.

3. A machine according to claim 1 or 2 in which the means to advance the machine body comprises in combination a radial gripper means longitudinally moveable relative to the machine body and thrust means connected between the gripper means and the machine body whereby when the radial gripper means is extended to engage a tunnel wall, the thrust means can move the machine body relative thereto, said gripper means when retracted being moveable longitudinally of the machine body.

4. A machine according to claim 1,2 or 3 in which a centering structure is mounted on the rear end of the machine body transverse moveable relative thereto and comprises a pair of laterally extendable members for engagement with the tunnel wall and a depending member to engage the tunnel floor, said lateral members having an equalizing displacement so that the depending member is positioned centrally relative to the tunnel before it is lowered to engage the floor and in which position it provides a datum point for accurately directional-positioning of the machine.

5. A machine according to any one of claims 1 to 4 in which the means for erecting circular tunnel support structures comprises a circular framework mounting a chain which is driven round the framework and on which segment of the ring yards are mounted and attached to each other in succession, and means for expanding the circular chain to enable location of the final segment.

6. A machine according to claim 4, in which a carrier, mounted on a longitudinal structure which overlies the machine body, delivers segments of ring girders to the erection means.

7. A machine according to claim 5, in which the longitudinal structure is adjustable longitudinally and vertically relative to the machine body.

8. A circular heading machine substantially as hereinbefore described with reference to the accompanying drawings.