AU708331B2

AU708331B2 - Excavation machine

Info

Publication number: AU708331B2
Application number: AU74000/96A
Authority: AU
Inventors: Tomofumi Ishino; Toshiaki Uehara
Original assignee: IHI Corp
Current assignee: IHI Corp
Priority date: 1995-11-27
Filing date: 1996-11-27
Publication date: 1999-08-05
Anticipated expiration: 2016-11-27
Also published as: AU7400096A

Description

4-.

BACKGROUND OF THE INVENTION Technical Field The present invention relates to a digging and excavating machine which digs the ground to form a gate road tunnel) or the like in a ground such as a coal mine.

Background Art Various methods of and apparatuses for underground coal mining are known in the art. One example of the conventional mining methods is schematically illustrated in Figure 24 of the accompanying drawings, which is generally referred to as a longwall mining method. In this mining method, two parallel gate roads or tunnels 2 and 3 are dug on both sides of a coal seam 1 to be mined in the directions as indicated by the two parallel dotted arrows and a heading road 4 is then formed to connect one gate road 2 with the other gate road 3 as indicated by another dotted arrow extending from the end of the right gate road 2 at the right angles. After that, a mining machine or excavator such as a cutter loader shearer: not shown) is advanced into the road 4 to dig or excavate the face of the longwall toward entrances of the gate roads 2 and 3, in the direction as indicated by the non-shaded arrow. The cutter loader carries a I I I coal to belt conveyors or the like (not shown) provided in the gate roads 2 and 3. The belt conveyors extend to the entrances of the gate roads 2 and 3. The belt conveyors then transfer the coal to the outside.

An example of the apparatuses for digging the gate roads 2 and 3 is illustrated in Figure 25 of the accompanying drawings, which is generally called a continuous miner and designated at 5. This mining machine 5 includes a main body or tracked vehicle 6, a boom 7 extending forwardly from the main body 6 and a cutting head 8 having a truncated cone shape and supported by the boom 7 at the end of the boom 7. By moving the boom 7 up, down, right and/or left, the cutting head 8 can excavate the ground in a desired shape. The excavated rocks and coals muck) are scooped up or collected by a muck collecting device 9 provided at the front of the main body 6 of the mining machine 5 and in turn transferred to a muck vehicle shuttle car) 11 provided behind the mining machine 5 by a conveyor 10 extending rearward through the main body 6. The mining machine 5 is operated by an operator who seats in and drives the mining machine 5. The mining machine 5 has a crawler 12 so that it can move by itself.

*°oo.The cutter head 8 of the illustrated conventional mining machine 5 is smaller than the ultimate sectional area to 9999 be excavated so that up, down, right and left movements of the cutting head 8 are requires for excavation of the gate road and 9..

therefore the excavation efficiency is low.

The gate and heading roads 2 to 4 created by the mining machine 5 are generally supported by rock bolts provided by a 9 9*

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rock bolting operation applied to the roof and ribs (top and side walls) of the gate roads. In order to perform a rock bolting operation, the excavating operation should be stopped. In other words, in order to insure safety of the operator of the mining machine 5, the cutter head 8 is stopped after advancing the mining machine 5 in an only small distance in the excavating direction, and after the rock bolting, the mining machine 5 is restarted and advanced again to excavate another small amount of ground. This also reduces the excavating speed. If the gate roads 2 and 3 are relatively long such as 4 or 5 kilometers, the time spent for excavating the gate roads occupies a considerable percentage of the time for a whole coal excavation operation.

To overcome the above drawbacks, a shield machine which is widely utilized in creation of tunnels and the like may be used since the shield machine is generally able to excavate the ultimate sectional area (cross section) of the gate road at one time while rock bolting to the roof and ribs of the gate roads.

However, the shield machine should attach arcuate segments on the .l walls of the tunnel to move in the excavating direction since o* it takes advantage of a counterforce force obtained from the segments attached onto the tunnel walls to advance in the excavating direction. Therefore, the shield machine spends a lot of time for attachment of the segments during the excavation.

The shield machine cannot be used unless the segments are attached to the walls of the tunnel or gate road. In addition, since the shield machine does not have capability of moving backward, a user encounters difficulty in pulling the shield machine backward from the excavation end (dead end) of the gate road to the gate road entrance. If the shield machine is to be left at the excavation end upon completion of the excavating operation of the gate road 2 (or one shield machine is required to one gate road. This dramatically raises the facility cost so that it is not practical.

The roof or top wall of the gate road 2 (or 3) is preferably horizontal so that the rock bolts are easily bolted in in a perpendicular direction. The floor or bottom wall of the gate road should also be horizontal since a conveyor for carrying the coal to the outside is placed on the floor and the muck transportation vehicle runs on the floor. Conventionally, however, no shield machines can create such horizontal roof and floor.

A certain type of conventional coal mining machines includes a pair of main cutters as well as associated endless chain cutters to dig the horizontal roof and floor. However, their drive mechanisms are so complicated and require a lot of parts. This raises the manufacturing cost of the mining machine.

**If a long gate road or tunnel should be formed, inspection and replacement of the cutters are necessary before the S mining machine completes the excavation of the gate road. To protect the operator(s) from possible danger, the cutter inspection and replacement are carried out at the safety area, i.e.

under that wall which the rock bolts for the wall support have been bolted in. In other words, the mining machine should be moved backward from the just excavated position to at least the Q:\OPER\SSB\74000-96.SPE 6/5/99 nearest safe location. After the inspection and/or replacement of the cutter, the mining machine is advanced again. This lowers the excavating efficiency.

SUMMARY OF THE INVENTION In accordance with the present invention thereis provided an excavation apparatus including: an excavation device for excavating a ground in a predetermined cross section to create a gate road; a frame work for supporting walls of the gate road excavated by the excavation device, the frame work including a *ill plurality of frames divided in its circumferential direction, the excavation device being mounted on a front portion of the 15 frame work, the frame work being divided into front and rear units in the excavation direction and a propelling device being provided therebetween; means for moving at least one of the frames inwardly so that a cross section of the frame work becomes smaller than that of the gate road; and means for bolting rock bolts into the wall of the gate road.

Q: \OPER\SSB\74000-96. SPE 6/5/99 In one embodiment, the frame work can be reduced in the diametrical direction by moving one or more frames inwardly so that the mining machine can easily be carried out to the outside.

In one embodiment, the moving means may be expansion/retraction jacks which press the frames of the rear unit against the walls of the gate road to obtain a counterforce from the walls of the gate road when the propelling device pushes the front unit forwardly in the excavation direction.

The moving means may press the frames of the front unit against the walls of the gate road to obtain a counterforce from the walls of the gate road when the propelling device pulls the rear unit toward the front unit.

The frame work may be divided into an upper frame which 15 supports a roof of the gate road, right and left side frames which support side walls respectively and a lower frame which contacts a bottom wall or floor of the gate road.

The mining machine may further include means for bolting in rock bolts into the walls of the gate road. Such means may be S 20 mounted on the rear unit. The rock bolts are bolted into the walls of the gate road behind the mining machine while the excavation device is excavating the working face of the ground in front of the mining machine. This raises the excavation efficiency.

The excavation device may include a plurality of main cutters juxtaposed at the same height linearly in a single plane in a width direction of the frame work and a plurality of trimming cutters for excavating those portions of the ground which the main cutters cannot excavate. The juxtaposed main cutters are arranged in a partly overlapping manner without causing intervention with each other. The main cutters may be rotary cutters which excavate the ground circularly in a manner such that a plurality of partly overlapping circles juxtaposed in the width direction of the frame work are made in the working face of the ground, and the trimming cutters have a linear shape extending along tangential lines of the partly overlapping circles made by the main cutters. Combination of the main cutters and trimming cutters allows the mining machine to excavate a gate road having a ultimate sectional area, particularly an oval gate road having horizontal roof and floor.

to Each of the main cutters may include a plurality of spokes extending radially from its rotation center shaft and a .too number of bits mounted on the spokes. Each spoke may be divisible in its longitudinal direction and part of the spoke may ooo ~be removed when the frame work of the mining machine is reduced 999999 in the diametrical direction.

.9 ~The mining machine may further include means for moving the trimming cutters inward or outward in the diametrical rr direction of the frame work. Such a mining machine can create a gate road directed upward or downward. The mining machine may further include means for moving the trimming cutters in the width direction of the frame work.

The mining machine may further include a cover member which is movable forward along the roof of the gate road from the frame work beyond the excavation device. When an operator inspects or replaces the main cutters and/or trimming cutters, the cover member is extended to support the roof in front of the mining machine. The cover member functions as an umbrella for the operator. The operator is protected from possible rockfall or collapse by the cover member when he/she inspects or replaces the cutters.

BRIEF DESCRIPTION OF THE ACCOMPANYING

DRAWINGS

Figure 1 is a lateral section of a mining machine according to one embodiment of the present invention; ooo0 Figure 2 illustrates a front view of the mining machine o shown in Figure 1 as viewed from the line A-A; Figure 3 is a view similar to Figure 2 but illustrates a mining machine when its frame work is reduced in a diametrical direction, more specifically in width and height directions; Figure 4 illustrates a sectional view taken along the line B-B of Figure 1; Figure 5 depicts a plan view of one of trimming cutters of the mining machine shown in Figure 1; Figure 6A illustrates a lateral view of the trimming cutter shown in Figure 5 in a normal condition together with its drive device; Figure 6B is a view similar to Figure 6A but illustrates the trimming cutter moved up (continuous line) and down (chain double-dashed line) from the normal position; Figure 7 is a sectional view taken along the line C-C of Figure 1; Figure 8 is a sectional view taken along the line D-D of Figure 1; Figure 9 is a sectional view taken along the line E-E of Figure 1; Figures 10A to 10E illustrate in combination a sequence of gate road excavation operations performed by the mining machine shown in Figure 1, in which Figure 10A illustrates a situation when propelling jacks are in retracted positions, Figure 10B illustrates a situation when a rear unit is expanded in a diametrical direction, the propelling jacks are extended to move a front unit forward and the working face is excavated by an excavation device of the mining machine, Figure 10C is a situation when the propelling jacks are extended to their maximum lengths, Figure 10D is a situation when the front unit is expanded in a diametrical direction and the propelling jacks are retracted to pull the rear unit toward the front unit, and Figure 10E shows a situation when the propelling jacks are retracted to their minimum lengths; Figures 11A to 11C illustrate in combination a series I- I of operations for towing the rear unit and in turn front unit to the outside from the dead end of the gate road upon completion of the gate road excavation, in which Figure 11A illustrates a situation when a tow vehicle is connected with the rear unit, Figure 11B illustrates a situation when the rear unit is separated from the front unit and towed by the vehicle, and Figure IIC is a situation when the tow vehicle is connected with the front unit; Figure 12 is a modified way of carrying out the mining machine from the gate road in which the front and rear frame segments are carried out together at a time by a tow vehicle; Figure 13 shows a front view of a mining machine according to a second embodiment of the present invention; Figure 14 illustrates a sectional view of the mining machine shown in Figure 13; Figure 15 depicts an enlarged front view of one spoke of a main cutter of the mining machine shown in Figure 13; 9999 Figure 16 illustrates a plan view of the spoke shown in oo Figure 9999 Figure 17 is a sectional view taken along the line F-F 9999 of Figure Figure 18 is a front view of one trimming cutter of the mining machine shown in Figure 13; Figure 19 is a cross section taken along the line G-G S of Figure 18; Figure 20 is an enlarged sectional view of one bearing device of the trimming cutter shown in Figure 18; Figures 21 is an enlarged end view of the trimming I Ir r Q:\OPER\SSB\74000-96.SPE 6/5/99 cutter shown in Figure 18 particularly illustrating a tilting mechanism for the trimming cutter; Figure 22 illustrates a cross section taken along the line H-H of Figure 18 showing a center bracket for the trimming cutter; Figure 23 shows a modification of the mining machine which includes three main cutters juxtaposed in a partly overlapping manner in a single plane in the width direction of the mining machine; Figure 24 is a view useful to explain a conventional longwall mining method; and Figure 25 schematically illustrates a conventional mining machine.

o DETAILED DESCRIPTION OF THE PREFERRED

EMBODIMENTS

*0 15 Now, preferred embodiments of the present invention will be ,ee described, by way of example only, and with reference to Figures 1 to 23 of the accompanying drawings.

First Embodiment: Figures 1 to 9 illustrate a structure of a first embodiment 20 of a mining machine according to the present invention. The e illustrated mining machine is particularly useful for excavation of gate roads or tunnels 2 and 3 in a coal mine. The mining machine includes an excavation device 21 for excavating a ground (coal seam or bed rock) 16 in an oval shape in cross section as viewed in the excavating direction (to the left from the right in Figure 1) with its major axis being horizontal, and further includes a frame work 22 positioned immediately behind the excavating device 21 in the excavating direction for supporting a peripheral wall of the gate road or tunnel 2 (or 3) excavated by the excavation device 21.

The frame work 22 has front and rear segments arranged linearly in the excavating direction. The front unit 23 and the rear unit 24 have a similar construction. The front unit 23 includes a lower body frame 25 which contacts a floor or bottom wall 15 of the gate road 2 (or an upper frame 26 for supporting a roof or top wall 13 of the gate road, and right and left side frames 27 and 28 (Figure 2) for supporting respective ribs or side walls of the gate road. These frames 25 to 28 are spaced in a circumferential direction at predetermined intervals as illustrated in Figure 2 so that they define an oval shape which corresponds to the oval shape to be excavated by the excavating device 21. It should be noted that the oval shape defined by the frames 25 to 28 is not an exact oval but has ~linear top and bottom sides since the gate road to be formed has to have horizontal roof and floor.

~The upper frame 26 includes an upper plate 29 which has a generally linear transverse cross section. The upper frame 26 is small in height. The side frame 27 (or 28) includes an outer plate 30 (or 31) which has an outwardly expanding arcuate .=.ooi S transverse cross section. The lower frame 25 includes a ooo.oi rectangular lower portion 33 having a bottom plate 32. The bottom plate 32 has a generally linear transverse cross section.

The lower frame 25 further includes four vertical portions 34 standing upward from four corners the rectangular lower portion 33 respectively, two upper transverse members 35 spanning the four upper ends of the vertical members 34 in the width direction of the mining machine respectively and two upper longitudinal members 36 (Figure 1) spanning the upper ends of the vertical members 34 in the longitudinal direction of the mining machine (or the excavating direction) respectively. As a result, the lower frame 25 has a generally rectangular-parallelopiped construction. As shown in Figure 1, a bulk head 37 is attached to the front of the lower frame 25 for partitioning the lower frame from the excavating device 21. Between the lower frame and the upper and side frames 26, 27 and 28, provided are expansion/retraction jacks 38 and 39 respectively so that the upper and side frames 26 to 28 can retract inwardly toward the lower frame 25, the mining machine can reduce its diameter.

Movements of the upper and side frames 26 to 28 are guided by guide members 40 and 41. The expansion/retraction jacks 38 and 39 and the guide members 40 and 41 constitute in combination means for moving the frames 26 to 28 inwardly so as to reduce the transverse cross section of the mining machine to be smaller than the cross sectional area of a gate road made upon excavation by the excavating device 21 or the oval shape defined by the excavating device 21. Four expansion/retraction jacks 38 are provided for the upper frame 26, as illustrated in Figures 1 and 8.

The jacks 38 are spacedly disposed along the upper longitudinal members 36 (two jacks 38 on each upper longitudinal member 36).

Each jack 38 includes a cylinder 42 extending vertically as shown in Figure 8 and a piston rod 43 movably received in the cylinder I- 42. The upper end of the piston rod 43 is coupled to the lower face of the upper frame 26. Therefore, the upper frame 26 is movable in the up and down directions between the lowest point defined by the upper longitudinal members 36 of the lower frame and the highest point defined by the most extended piston rods 43. As illustrated in Figures 7 and 9, each of the guides includes a hollow cylindrical element 44 provided at the top of the associated vertical member 34 and a rod element 45 hanging from the upper frame 26 to be coaxial with the cylindrical element 44 and slidably received in the associated cylindrical element 44. Slide movements of the rod element 45 in the cylindrical element 44 guide the up and down movements of the upper frame 26. As understood from Figures 9 and 1i, eight expansion/retraction jacks 39 extending outwardly in the width direction are provided for the side frames 27 and 28, four of which jacks are shown in Figure 9. Each jack 39 includes a main device 46 which is located at the top or bottom of the vertical C member 34 and directed right or left, and a piston rod 47 extending horizontally outward from the vertical member 34 to the inner surface of the side frame 27 (or 28). The jack guides 41 are provided near the expansion/retraction jacks 39 respectively as depicted in Figure 1. As best seen in Figure 7, each guide 41 includes a post member 48 extending inwardly horizontally from o the inner surface of the side frame 27 (or 28) and a cylindrical space 49 formed in the associated vertical member 34 for slidably receiving the post member 48.

As shown in Figure 1, propulsion jacks 50 are provided i between the front unit 23 and rear unit 24 for generating a propelling force necessary for the excavation operation of the mining machine. The propulsion jacks 50 are another expansion/retraction devices. Four propulsion jacks 50 are provided at four corners of the lower frame 25 of the rear unit 24 respectively as viewed in the longitudinal direction of the mining machine as depicted in Figure 9. As seen in Figure 1, each of the two upper propulsion jacks 50 includes a main body 51 extending along the upper longitudinal member 52 of the rear unit 24 and each of the two lower propulsion jacks 51 includes a main body 51 extending along the lower member 33 of the rear unit 24.

Because of this structure, the upper longitudinal members 52 of the rear unit 24 are particularly designed to be strong enough to support the propulsion jacks 50. Consequently, the upper longitudinal members 52 of the rear unit 24 are more rigid than the upper longitudinal members 36 of the front unit 23. The expansion/retraction jacks 39 and guides 41 of the rear unit 24 are located at positions which do not intervene with the propulsion jacks 50. The front end of a piston rod 53 of each propulsion jack 50 is detachably attached to the rear end of the lower frame 25. The expansion/retraction movements of the propelling jacks 50 and the expansion/retraction movements of the frames 26 to 28 caused by the expansion/retraction jacks 38 and 39 are S carried out in a cooperative manner to perform the excavation operation. Specifically, when the front unit 23 should be pushed forward by the propelling jacks 50, the upper frame 25 and side frames 27 and 28 of the rear frame segment 24 are expanded to the roof 13 and ribs of the gate road 2 (or 3) respectively by I I their jacks 38 and 39 so that the rear unit is fixed. Then, using the fixed rear unit 24, the propelling jacks 50 are extended to push the front unit 23. A counterforce necessary for the front unit pushing operation is obtained from the gate road walls around the rear unit 24. In other words, acquisition of the counterforce does not depend upon only a friction with the gate road floor. Accordingly, the front unit can reliably advance in the excavating direction. After the front unit 23 advances a certain distance, the rear unit 24 is pulled toward the front unit 23. In order to carry out this pulling operation, the upper frame 25 and side frames 27 and 28 of the front unit 23 are pressed against the roof and side walls of the gate road by the expansion/retraction jacks 38 and 39 of the front unit 23 so as to fix the front unit 23. In the meantime, the upper and side frames 26 to 28 of the rear unit 24 are retracted in a diametrical direction of the frame work 22 to free the rear unit 24 from the gate road walls. Then, the propelling jacks are retracted to pull the rear unit 24. A counterforce necessary for this pulling operation is obtained from the gate road walls around the front unit 23. The excavation of the working face or ground 16 is carried out when the front unit 23 is pushed forward.

Referring now to Figure 2, the excavating device 21 includes a pair of right and left main cutters 61 and 62 and a pair of upper and lower trimming cutters 63 and 64. Each of the main cutters 61 and 62 is adapted to rotate about its axis extending in the longitudinal direction of the mining machine.

I ill The trimming cutters 63 and 64 are provided to excavate those portions of the ground 16 which the main cutters 61 and 62 cannot excavate, which portions are indicated by the doubledotted line Q in Figure 2. Each of the main cutters 61 and 62 includes the rotation center shaft 65, three spokes 66 radially extending from the front end of the shaft 65 and a plurality of bits (or cutter picks) 67 arranged on an associated spoke 66.

The bits 67 are spaced in the longitudinal direction of the associated spoke 66. The bits 67 project forwardly from the associated spoke 66 in the excavating direction as shown in Figure 1. Each bit 67 has an arc shape as viewed from the front as depicted in Figure 2. Another arc-shaped bits 68 are mounted on the front end of each shaft 65. It should be noted that four bits 67 are provided on each spoke 66 in the illustrated embodiment, but less or more bits may be provided. It should also be noted that water injection nozzles may be provided on the shafts 65 and/or spokes 66 so that water jets or atomized S* water sprays are applied to the working face 16 (Figure 1) for prevention of scattering of coarse particulate or dust and oo o generation of spark upon excavation. The spokes 66 of the right main cutter 61 and those of the left main cutter 62 are arranged to extend in the same plane as viewed in the transverse direction at the same height and in a non-intervening manner as viewed from the front, one spoke of one main cutter always positions between two spokes of the other main cutter as illustrated in Figure 2. The main cutters 61 and 62 are rotated in opposite directions.

Referring back to Figure 1, each of the shafts extends backwardly horizontally from the spoke portion 66 and is supported by the associated vertical member 34 of the front unit 23 at its approximate rear end. To the rear end of each shaft mounted is a gear 69 which meshes with a gear 71. The gear 71 is indirectly connected with an electric motor 70 placed on a lower portion 33 of the lower frame 26 of the front unit 23.

Between the gear 71 and electric motor 70, provided is a speed reduction mechanism 72. Rotation power of the electric motor is transmitted to the main cutters 61 and 62 and causes the main cutters to rotate in opposite directions for excavation of the working face 16 in front of the main cutters.

Referring to Figure 3, each spoke 66 has a removable approximate outer half 66a so that the length of the spoke 66 can be reduced by removing the removable element 66a from the reminder of the spoke. The reduced spoke terminates at the line 73. The length reduction may be required upon diametrical reduction of the frame device 22 as understood from change from the phantom lines before size reduction) to the solid lines after size reduction) in Figure 3. Specifically, when the upper and side frames 26 to 28 are moved inward, the •ooo four spokes 66 projecting outward from the shrunk frame work 22 will be reduced in length. In order to enable such length reduc- 0 tion of the spoke 66, the division surface 73 of the removable element 66a may have a projection (or recess), the mating surface 73 of the fixed half of the spoke 66 may have a mating recess (or projection) and the removable and fixed halves may be joined by :bolts and nuts (not shown). It should be noted that all of the bolts and nuts (not shown). It should be noted that all of the

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spokes 66 do not have to have the removable elements 66a. In other words, those spokes 66 which project from the reduced frame work 22 may only have the removable elements 66a since the spokes 66 generally stop at predetermined positions as shown in Figure 3. It should also be noted that the length of the removable portion 66a of the spoke 66 in the longitudinal direction of the spoke 66 can be determined arbitrarily as far as the reduced spoke does not project from the reduced frame work and it does not have to be approximate half the length of the spoke 66.

Each or some or all of the spokes 66 have a bucket 74 on its back side in the rotation direction as shown in Figure 3.

The buckets 74 are provided to catch or scoop up coal and rocks excavated by the excavating device 21 (Figure 1) and in turn to feed them onto a conveyor 76 via chutes 75 as best illustrated in. Figure 4. One chute 75 is provided for each main cutter 61/62. The chutes 75 are directed downward and toward the center of the frame work 22 respectively since the single conveyooo or 76 extends through the center of the frame work 22 and located *o below the chutes 75. As shown in Figure i, the conveyor 76 includes an endless belt 78 which is engaged over a front roller 77 positioned below the chutes 75 and a rear roller (not shown) provided behind the rear unit 24. The inner surface of the endless belt 78 is guided and supported by a plurality of guide rollers 79 provided in the lower frames 25 of the front and rear .:.oi units 23 and 24 as shown in Figure 8. As seen in Figure 1, the belt 78 as a whole extends in a slightly upward diagonal direction from the front roller 77 and then horizontally toward the end of the frame work 22. The coal and rocks carried to the end

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of the frame work 22 by the conveyor 76 are transferred onto another conveyor (not shown) or a truck (not shown) waiting at the end of the mining machine for transportation to another place.

Referring to Figure 2, each of the upper and lower trimming cutters 63 and 64, which have a substantially same construction, includes a cutter main body 80 of predetermined length extending in the width direction of the frame work 22 and a plurality of bits 81 spacedly buried in the main body 80 in the longitudinal direction of the main body 80. Each trimming cutter 63/64 therefore has a saw shape. As seen in Figure 1, the trimming cutters 63 and 64 are mounted on the front of the front unit 23 such that they are positioned closely behind the buckets 74 of the main cutters 61 and 62. The upper trimming cutter 63 is positioned on the upper frame 26 of the front unit 23 and the lower trimming cutter 64 is positioned on the lower portion 33 Sof the lower frame 25 of the front unit 23. As shown in Figure oo 5, the cutter main body 80 is mounted on (or received in) a boxshaped bracket member or housing 82 in a manner such that the bits 81 are only exposed. The cutter main body 80 is supported via a translation block 84 by a guide rod 83 extending horizontally in the width direction of the bracket member 82 or mining machine. The guide rod 83 is supported by opposite side plates 82a of the bracket member 82 at its ends. The guide rod 83 extends through the translation block 84 and the translation block 84 is able to slide on the guide rod 83. The translation a. block 84 is connected with a cylinder device 85 for reciprocal slide movement on the guide rod 83. The cylinder device extends in parallel to the guide rod 83 and its main body or cylinder 85a is mounted on a back or base plate 82b of the bracket member 82 via a bracket 86 at one end. A free end of a piston rod 85b extendible/retractable from/in the cylinder 85a is coupled to the translation block 84 via another bracket 87. Accordingly, extension and retraction movements of the cylinder device cause the trimming cutter 63 (or 64) to move right and left.

Right and left limitations of such movements are determined by stops 83a mounted on the guide rod 83 respectively.

As illustrated in Figure 6A, each of the upper and lower bracket members 82 is provided with actuators 88 (one actuator is only illustrated) for rotating the bracket 82 together with the trimming cuter 63/64 about a pivot 92. The upper and lower bracket members are substantially mirror image members.

Each of the actuators 88 includes a cylinder 88a pivotably connected with the frame lower portion 33 or the upper frame 26 via a bracket 89 at its end and a piston rod 88b slidably received in i the cylinder 88a and pivotably connected with the upper back of o* the back plate 82b via a bracket 90 at its end. The lower back of the back plate 82b of the trimming cutter housing 82 is supported by the frame lower portion 33 or the upper frame 26 via the pivot shaft 92 via brackets 91 (only one bracket is illustrated). The supporting shaft 92 extends in the width direction of the mining machine. Therefore, expansion and retraction movements of the actuators 88 can cause the trimming cutter housing 82 to pivot outward and inward about the shaft 92 as depicted in Figure 6B. Upon such pivot movements, the cutter I bits 81 of the trimming cutter 63/64 are also moved outward and inward. The trimming cutter 63/64 is held in the posture as shown in Figure 6A in a normal excavation operation and the cutter bits 81 of the trimming cutter are directed in a particular angle 0 relative to the vertical direction, for example degrees. If necessary for some reasons encountered during the excavation operation, the bracket member 82 is rotated about the shaft 92 clockwise or inward as illustrated in Figure 6B by the solid line to change the position of the bits 81 inwardly by retracting the piston rod 88b of the actuator 88. The angle alpha is defined by the inwardly rotated trimming cutter housing 82 with respect to the horizontal direction. This also results in inward retraction of the trimming cutter housing 82. When adjustment of overbreak or outbreak excavation outside the oval shape defined by the frames 25 to 28 as seen in Figure 2) or curved excavation should be carried out, the actuators 88 of the upper and lower trimming cutters 63 and 64 are both extended from the normal positions or the actuators 88 of the upper or lower trimming cutter 63/64 are only extended. The bits 81 of the r trimming cutter(s) 63/64 project diametrically outward from the mining machine as indicated by the chain double-dashed lines (P) in Figure 6B upon extension of the rods 88b of the actuators 88.

When the trimming cutters 63 and 64 are rotated inward, there is -i ~a possibility that the trimming cutter housings 82 collide with S the bulk head 37 located behind the trimming cutters 63 and 64 as understood from Figure 1. To avoid such collision, that portion of the frame lower portion 33 or upper frame 26 which I I supports the actuators 88 may be slid forwardly a distance L as illustrated in Figure 6B from the position shown in Figure 6A.

The slide movement of the actuator supporting portion may be performed by an associated actuator device 93.

Each trimming cutter housing 82 is defined by the back plate 82b, an inclined front plate guide plate) 82c and the two end plates 82a. In the cross section as shown in Figure 6A, the inclined front plate 82c extends from the top of the back plate 82b forwardly and then downwardly diagonally. The inclined plate 82c is generally directed inward (upward in Figure 6A).

The cutter bits 81 project from the end of the front plate 82c.

The guide plate 82c of the upper trimming cutter 63 guides the excavated coal into the chutes 75 (Figure 1) and that of the lower trimming cutter 64 pushes the coal forwardly upon the excavation movement so that the buckets 74 of the main cutters 61 and 62 (Figure 2) can scoop them up. As shown in Figure 6A, a reinforcing element 94 is further provided behind the guide rod 83 in each trimming cutter housing 82 to sufficiently support the o.

o. ~trimming cutter 63/64 which is subjected to a strong counterforce from the ground upon excavation. The reinforcing element 94 extends in the width direction of the trimming cutter housing 82.

Referring back to Figure i, a covering member 95 is S provided on the upper frame 26 of the front unit 23. The covering member 95 is adapted to be movable along the roof or top wall

S

of the gate road 2/3 created by the excavation device 21. As best illustrated in Figure 2, the cover member 95 is an outer plate of the upper plate 29. The upper plate 29 includes an inner plate 96, and the outer plate or cover plate 95 is slidable 1 t relative to the inner plate 96 in the longitudinal direction of the mining machine. As illustrated in Figure i, a cylinder device 97 is mounted on the upper frame 26 of the front unit 23 and a free end of a piston rod 97a of the cylinder device 97 is coupled with the cover plate 95. Upon extension of the piston rod 97a, the cover plate 95 projects forward of the digging device 21 as indicated by the double-dot line. When the cutter bits 81/67/68 should be replaced with new ones or inspection of the cutter bits 81/67/68 is required during the excavation operation, the mining machine is moved backward from the just excavated working face 16 as depicted in Figure 1 and stopped. Then, an operator M walks into a clearance between the working face 16 and the digging device 21. In this situation, the cover plate has been extended forward so that the operator M is protected from possible collapse from the roof 13 of the gate road.

Normally, the cover plate 95 is positioned behind the main cutters.

rooo ~Referring to Figure 9, ventilation pipes 98 extending in the longitudinal direction of the mining machine are mounted along both sides of the lower frame An operator's room (not shown) and various power devices (not shown) for the jacks 38, 39, 50 etc. are provided in oor the rear unit 24. It should be noted that the operator's room may be separated from the frame work 22 and positioned some S• distance behind the frame work 22. In this case, the mining machine may be remote controlled by the operator in the opera- 0 tor's room.

As shown in Figure 1, a rock bolting device 100 for bolting rock bolts 99 into the roof 13 and ribs of the gate road 2/3 is also provided on a rear deck (not shown) of the rear frame 24. Therefore, the mining machine of the present invention can bolt the rock bolts into the walls of the gate road using the rock bolting device 100 while performing the excavation operation. It should be noted that the bolt device 100 may be carried by another vehicle which runs after the mining machine.

Now, the excavation operation of the gate road or tunnel 2/3 by the mining machine having the above described construction will be described with reference to Figures through 12.

Referring first to Figure 10A, the propelling jacks are in a retracted state at the beginning. Using the expansion/retraction jacks 38 and 39, the transverse cross of the front unit 23 is adjusted to be slightly smaller than a cross section of the ground 16 to be excavated by the excavation *S6.

device 21. Accordingly, a small clearance S1 is formed between *m the roof 13 of the gate road 2/3 and the upper surface of the S- upper frame 26 of the front unit 23 of the mining machine.

Likewise, small clearances are formed between the side walls of the gate road 2/3 and the side frames 27 and 28 of the front unit 23 (not shown). The rear unit 24, on the other hand, is entirely pressed against the top and side walls of the gate road 2/3 upon expansion of the jacks 38 and 39 and no clearance is formed around the rear unit 24. Specifically, the top frame 26 as well as the side frames 27 and 28 of the rear unit 24 are forced outwardly in the diametrical direction by the expansion jacks 38 and 39 respectively. After that, the main cutters 61 and 62 as well as the trimming cutters 63 and 64 are activated and the conveyor 76 is driven. Then, the propelling jacks 50 are elongated forwardly so that the main cutters 61 and 62 contact the working face 16 and excavate a substantial portion of the working face 16 by their rotation and forwardly directed force exerted by the jacks 50 as depicted in Figure 10B. At the same time, the trimming cutters 63 and 64 excavate those portions (Q) (Figure 2) of the working face 16 which the main cutters 61 and 62 cannot excavate. As illustrated in Figure 2, the main cutters 61 and 62 define two overlapping juxtaposed circles at the same height so that horizontally extending upper and lower tangential lines mutual for these circles are defined. The trimming cutters 63 and 64 extend along these tangential lines. The triangular portions which are not dug by the main cutters 61 and 62 are relatively easily separated from the ground 16 by the trimming 4 cutters 63 and 64 since the ground is the coal seam and/or the trimming cutters 63 and 64 are moved in the width direction by the reciprocal movement devices 85 although the trimming cutters 63 and 64 do not have a similar shape to the remaining portion the remaining portions are easily peeled off due S to vibrations and/or crackings made by the horizontally extending

OS.

and generally linear trimming cutters 63 and 64. The excavated muck such as coal is scooped up by the buckets 74 and taken away from the excavation area to the rear of the mining machine by the chutes 75 and conveyor 76.

S. When the propelling jacks 50 are extended to their *When the propelling jacks 50 are extended to their maximum lengths as shown in Figure 10C, the expansion/retraction jacks 38 and 39 of the front unit 23 are extended to move the upper frame 26 and side frames 27 and 28 of the front unit 23 outwardly in the diametrical direction until they are pressed against the top and side walls roof and ribs) of the gate road 2/3 respectively. Then, the expansion/retraction jacks 38 and 39 of the rear unit 24 are retracted to allow the frames 26 to 28 of the rear unit 24 to leave the top and side walls of the gate road 2/3. Thus, a clearance 81 is now formed between the upper surface of the upper frame 26 of the rear unit 24 and the roof 13 of the gate road as well as between the side frames 27 and 28 of the rear unit 24 and the neighboring side walls of the gate road 2/3. After that, the propelling jacks 50 are retracted to pull the rear unit 24 forwardly as depicted in Figure During or after the pulling operation of the rear unit 24 and/or during the excavation operation by the excavation device 21, the bolting machine 100 which incorporates a drill and a chemicals oleo feeder is activated such that a drilling operation is performed 9*9* go° 9 Soo* to the top and side walls of the excavated gate road to make bores for insertion of the rock bolts, chemical grouting is carried out using these bores for stabilization and the rock bolts 99 are struck into the bores (Figure The bolts are S tightened and fixed by nuts. It should be noted that a net or the like may be used for the fixing of the bolts 99. When the *599.9 propulsion jacks 50 are retracted to their minimum lengths as shown in Figure 10E, the front unit 23 is reduced in size in the diametrical direction while the rear unit 24 is expanded to return to the initial condition as shown in Figure 10A. Such a I i sequence of operations is repeated as required to finish the whole excavation operation.

When the whole excavation operation is completed, all of the expansion/retraction jacks 38 and 39 are retracted to the minimum lengths respectively so that the frame work 22 as a whole becomes considerably smaller than the sectional area of the gate road 2/3 as shown in Figure 11A. In this condition, there is a relatively large clearance S3 formed between the top and side walls of the gate road and the frames 26 to 28 of the front and rear units 23 and 24. In addition, the outer halves 66a of the spokes 66 of the main cutters 61 and 62 are removed as illustrated in Figure 3 so that the spokes 66 do not project outward from the shrunk frame work 22. Then, the piston rod 53 of each propulsion jack 50 is disconnected from the front unit 23 and a tow car 101 waiting behind the rear unit 24 is connected to the rear unit 24 via a coupling member 102. By driving the tow car S 101 to the entrance of the gate road 2/3, the rear unit 24 is o. transported to the outside as shown in Figure 11B. During the transportation, the rear of the rear unit 24 is lifted up slightly to reduce a friction between the rear unit 24 and the floor 15 (Figure 1) of the gate road. It should be noted that rollers may be provided at the lower front portion of the rear unit 24 *0 for easy towing. If the ground is the coal seam, the floor 15 of the gate road 2/3 is smooth and a friction coefficient is small so that no difficulty may be encountered during the towing of the rear unit 24. In such a case, accordingly, a relatively small tow vehicle 101 is sufficient. After the rear unit 24 is carried to the outside, the tow vehicle 101 advances into the gate road 2/3 again and is connected with the front unit 23. If the lower trimming cutter 64 (Figure 3) is coplanar to or projects downward from the lower surface of the frame work 22, the cutter bits of the lower trimming cutter 64 may contact the floor of the gate road 2/3 and a large friction may be generated upon towing of the front unit 23, which would in turn result in damage and breakage of the lower trimming cutter 64. Therefore, the actuators 88 of the lower trimming cutter 64 are activated to retract the piston rods 88b as illustrated in Figure 6B so that the lower trimming cutter 64 is raised and safely positioned inside the frame work 22. Then, the tow vehicle 101 joined with the front unit 23 is driven to the outside as shown in Figure 11C.

It should be noted that connection between the front and rear units 23 and 24 may be maintained and the front and rear units 23 and 24 are towed by the vehicle 101 to the outside together if circumstances allow it as depicted in Figure 12.

Upon completion of the excavation of the gate roads 2 and 3, a heading road 4 should be formed to connect the 9**9 dead ends of the gate roads 2 and 3 with each other (Figure 24). In the heading road 4 excavating operation, the mining machine may be turned 90 degrees at the dead end of the gate 99e road 2. However, it is generally difficult for the mining 9"9 machine to turn inside the gate road 2 since the gate road *o9 is small. In addition, the heading road 4 is usually very short as compared with the gate roads 2 and 3. Therefore, a conventional mining machine as shown in Figure 25 may be used to dig the heading road 4 after the mining machine k _I rl

_I~

of the present invention is taken out from the gate roads 2 and 3.

After the U-shaped roads 2 to 4 are created, a drum cutter is carried into the heading road 4 and excavates the coal seam 1 between the gate roads 2 and 3 for coal mining (Figure 24).

Since the mining machine of the invention includes the excavating device 21 which digs the ground 16 in an oval cross section, and the frame device 22 which supports the peripheral wall of the gate road 2/3 and which is extendible/retractable in the diametrical direction as well as in the longitudinal direction, the excavation operation can be carried out in an efficient manner in a shorter period. Also, since the bolting operation of the rock bolts 99 can be performed simultaneously, the excavation efficiency is greatly improved. In addition, transportation of the mining machine to the outside after completion of the gate road excavation is carried out quite easily and smoothly so that oo the time required for the excavation of the gate roads 2 and 3 oooo and the coal mining is dramatically reduced. Since the frame device 22 is divided into the front and rear segments 23 and 24 and the propelling jacks 50 are provided between these units 23 and 24, the frame work 22 can change its length in the longitudinal direction and can generate a sufficient propulsion force in S* cooperation with the radial expansion enabled by the jacks 38 and 39, without depending upon only a friction with the floor of the gate road generated by its weight. Therefore, the weight of the mining machine may be reduced and the excavation speed can be raised.

Since the excavating device 21 includes a pair of main rotary cutters 61 and 62 and a pair of linear trimming cutters 63 and 64 which are arranged to define a single oval shape having linear top and bottom sides, it is possible to easily excavate the gate road of oval cross section having the horizontal top side or roof (13) and bottom side or floor Since the trimming cutters 63 and 64 are activated by the cylinder devices the structure relating to the trimming cutters including the guide rods 83 is compact. Therefore, a less number of parts is required for the trimming cutters and their drive mechanisms.

Since the trimming cutters 63 and 64 are pivotable inward and outward and movable in the longitudinal direction by the actuators 88 as shown in Figures 6A and 6B, replacement of the cutter bits 81 and the outbreak excavation beyond the oval shape defined by the frames 25 to 28 of Figure 2) can be performed easily. Because of the same reason, the outbreak by the upper 0S e oo ~trimming cutter 63 and that by the lower trimming cutter 64 can *see 0#0.

also be conducted independently and an upwardly or downwardly •go• directed gate road can also be excavated.

S.

oo Since the upper frame 26 is provided with the cover plate 95 which is slidably extendible in the longitudinal direceve.

S tion of the mining machine along the roof of the gate road by the cylinder device 97, it is possible to protect the operator who inspects and/or replaces the main cutters 61 and 62 and/or V0 the trimming cutters 63 and 64 from possible collapse by moving o the mining machine backward only a small distance and supporting the roof between the working face 16 and the main cutters 61 and ~L I i I 62. Conventionally, the mining machine should be moved backward some distance until it reaches a safety position where the roof and ribs are rigidly supported and secured by the rock bolts 99.

In the present invention, therefore, the maintenance can be conducted quickly and it also contributes reduction of the time required for the entire excavation operation.

Second Embodiment: A second embodiment of the present invention will be described with reference to Figures 13 through 23. It should be noted that the mining machine of this embodiment has some mutual points with that of the first embodiment and therefore same or similar reference numerals are used in both of the embodiments to designate the same or similar parts and detailed description of such parts is omitted in the following description.

Referring to Figure 13, a mining machine of this embodiment includes a pair of right and left main cutters 111 and 112 and a pair of upper and lower trimming cutters 113 and 114 like the first embodiment. A major difference as compared with the foregoing embodiment shown in Figure 2 lies in that the trimming cutters 113 and 114 of this embodiment are drum-shaped cutters.

The main cutters 111 and 112 are also different from those of the foregoing embodiment in shape and structure of the spoke 115.

S Specifically, each spoke 115 has a circular cross section and a number of bits 116 is mounted on each spoke 115 in a zig-zag 0:00. manner. As illustrated in Figure 15, a first row of bits 116a are arranged along the center line Cs of each spoke 115 at equal intervals and a second row of bits 116b are arranged along anothr er line parallel to the center line Cs and offset rearward with respect to the rotation direction R of the spoke 115 and offset in the longitudinal direction of the spoke by half a pitch of the first bits 116a. Each bit 116 is comprised of a hard metallic chip having a cylindrical shape with its free end being sharp.

Each bit 116 is supported by a holder 117 in a certain direction.

In this particular embodiment, the bits 116 are held in an approximate 45-degree direction relative to the working face 16 with respect to the rotation direction R as viewed from the longitudinal direction of the spoke 115 as depicted in Figure 17.

A third bit 116c is mounted on the free end of each spoke 115 as shown in Figure 15 such that it slightly projects outward from the front end of the spoke. This bit 116c is held in a predetermined angle beta (for example, 45 degrees) relative to the end face of the spoke 115 as illustrated in Figure 16. If viewed from the above (Figure 14), therefore, the first and second rows of bits 116a and 116b and the third bit 116c define a diagonal 0•0 surface 16a like a chamfering at the front end corner of each spoke 115 as shown in Figure 16. Accordingly, the ground or oooo S. working face 16 is excavated like a shallow basin with its peooo o riphery being defined by the inclined excavation surface 16a.

The bits 116 are mounted on the spoke 115 as well as on the root S portion 118 of the spoke and a front end face of a rotation center shaft 119 as illustrated in Figure 13. As seen in Figure 14, the root portion of the spoke 115 and the front end face of the rotation center shaft 119 are coplanar but offset forward from the spoke 115, and those bits 116d which are mounted on the spoke root portion 118 and the rotation shaft 119 are positioned I I forward of the bits 116a to 116c on the spoke 115.

Each spoke 115 is provide with a bucket 120 on its back as shown in Figure 14. Each bucket 120 has an arcuate bucket guide 121 which is fixedly located inward of the bucket 120 along part of the circular passage of the bucket 120 about the rotation center shaft 119 as illustrated in Figure 13. Until the coal and rocks (muck) scooped up by each bucket 120 enter an associated chute 122, the bucket 120 moves along the associated bucket guide 121 so that the dropping of the coal from the bucket 120 is prevented. The upper end or muck entrance opening of each chute 122 is located at the upper end of the associated bucket guide 121 above the rotation shaft 119. As illustrated in Figure 14, each chute 122 bends downwardly and rearwardly from its upper opening beyond the rotation shaft 119. The lower end of the chute 122 is positioned slightly above a front end area of a conveyor 123. Although not shown, each spoke 115 has a divisible structure like the spoke of the first embodiment and a predeteroooo o' ~mined part of the spoke 115 can be removed from the reminder for reduction of the frame work of the mining machine.

The trimming cutters 113 and 114 will now be described with reference to Figures 18 and 19 in detail. These trimming cutters have the substantially same structure so that one of them will be described and illustrated in the drawings.

*999o9 Each trimming cutter 113/114 includes a solid drum- *969** 9 shaped shaft body 124 having a predetermined diameter and a redetermined length and a number of cutter bits 125 arranged on the outer periphery of the drum-like shaft body 124. Each of the I I I bits 125 is comprised of a hard metallic chip having a cylindrical shape with its free end being sharp and a holder 126 (Figure 19) for supporting the hard metallic chip like the bit 116 of the main cutter 111/112. The cutter bits 125 are provided on the entire peripheral surface of the shaft body 124. The cutter bits 125 are arranged in a manner such that six rows of bits are created in the longitudinal direction of the shaft body. (Three rows of them are illustrated in Figure 18 and the same pattern of three rows of bits are provided on the opposite side as understood from Figure 19.) These three rows of bits are shifted relative to each other in the longitudinal direction of the shaft body 124. In each row, the bits are spaced at same intervals in the longitudinal direction of the shaft body 124. As shown in Figure 19, the shaft body 124 has a cylindrical bracket 127 which can be dividable into two equal pieces. The cylindrical bracket 127 defines the outer surface of the shaft body 124 and the holders 126 are mounted on the cylindrical bracket 127. The o cylindrical bracket 127 has flanges 128 at its division portions and bolts 129 are used to firmly hold the cylindrical bracket 127 ~over the shaft of the trimming cutter 113/114 by screwing the 444.

bolts 129 into bores made in the flanges 128. The cylindrical bracket 127 is therefore removable from the shaft of the trimming cutter 113/114 by unscrewing the bolts 129. It should be noted that the holders 126 and the cylindrical bracket 127 may be manufactured as one piece device and this device may be attached Sover the shaft of the trimming cutter. It should also be noted that the cylindrical bracket 127 may be divisible in its length Sdirection.

direction.

~I

Referring now to Figures 20 and 13, the ends of the drum-shaped shaft body 124 of the upper trimming cutter 113 are journally supported by bearing members 130 which are embedded in the upper frame 26 and the same of the lower trimming cutter 114 are journally supported by bearing members 130 embedded in the lower frame 25. Each bearing device 130 has a through hole into which a bearing 131 is fitted for rotatably supporting the end of the shaft body 124. A hydraulic motor 132 is attached to the exposed end face of the shaft body 124. Specifically, an output end 133 of the hydraulic motor 132 is coupled with the end face of the shaft body 124 via a gear coupling 134 by bolts 135. The end face of the shaft body 124 has a recess to receive the output end 133 of the hydraulic motor 132. A main body of the hydraulic motor 132 is also mounted on the exposed end face of the bearing device 130 at its flange 136 by bolts 137 as depicted in Figure 21. Upon actuation of the hydraulic motor 132, the shaft body 124 rotates. It should be noted that the hydraulic motor(s) 132 oo ~may be mounted on the both or either one of the ends of the shaft body 124. The gear coupling 134 is provided for preventing a harmful load such as torsion from the shaft body 124 from being transmitted to the hydraulic motor 132. The gear coupling 134 can absorb such a load. The gear coupling 134 is fitted over the output end 133 of the hydraulic motor 132 and held at a predetermined position by a positioning plate 138 and bolts 139 for securing the plate 138.

A through hole 140 is bored along the center line of the shaft body 124 as shown in Figure 20. This hole 140 is used as a water passage. As illustrated in Figure 19, a number of radial holes 141 is also bored in the shaft body 124 which radially extend from the center water hole 140. These radial bores 141 extend to associated nozzles 142 buried in the outer peripheral surface of the shaft body 124 or the cylindrical bracket 127. The nozzles 142 are arranged at positions which do not intervene with the cutter bits 125. As shown in Figure 20, the center water passage 140 is communicated with another water passage (not shown) penetrating the hydraulic motor 132 and this water passage is communicated with a water source (not shown) via a swivel 181 attached to the end of the hydraulic motor 132. In this embodiment, the water is supplied to the water passage 140 at least while the hydraulic motor 132 is being activated. As the water is supplied to the center water passage 140, it reaches the nozzles 142 via the radial water passages 141 and is injected outward. The water jets or sprays from the nozzles 142 suppress scattering of dusts and small/coarse particles created o• upon the excavation by the trimming cutter 113/114.

Figure 21 illustrates the end face of the lower trimming cutter 114. As depicted, a planar flange 143 extends rearward from each bearing device 130 and a pin 144 which extends in parallel to the shaft body 124 is provided near the end of the flange 143. A bracket plate 146 extends forward from a front plate 145 of the lower frame 25 and a hole is formed near the end of the bracket plate 146. The pin 144 of the flange 143 is fitted in the hole of the bracket plate 146 such that the bearing device 130 can pivot about the pint 144 supported by the lower frame 25. Above the pin 144, provided is a tilt cylinder device 1- 147 which spans the bracket plate 146 and the flange 143. A root portion of the tilt cylinder device 147 has a pin 148 which is similar to the pin 144. The pin 148 is also fitted in an upper hole formed in the bracket plate 146 so that the tilt cylinder 147 can also pivot about the pin 148. The tilt cylinder device 147 includes a piston rod 149 and a front end of the piston rod 149 has a folk portion 150 which is pivotably connected to the upper portion of the flange 143 by a pin 151. Therefore, as the piston rod 149 is elongated, the trimming cutter 114 is tilted downward and projects below the frame work 22 whereas as the piston rod 149 is retracted, it is tilted upward and confined in the frame work 22. During the normal excavation operation, a circular orbit or trajectory 150 in cross section is created by rotation of the trimming cutter 114 as indicated by the chain double-dashed line circle in Figure 21 and the lower surface of the lower frame 25 defines a plane which is parallel to the floor of the gate road. The tangential line from the lowest point of o the circle 150 defines a plane coplanar to the lower surface of r°•o the lower frame 25. When the excavation below the level of the lower frame is required, the cylinder device 147 is extended and the lower trimming cutter 114 projects downward beyond the lower frame 25. In this case, the horizontal tangential line from the lowest point of the trajectory circle of the lower trimming cutter 114 or the lower excavation line would be the chain double-dashed line 152.

Stops 154 are provided on the front plate 145 of the lower frame 25 above and below the bracket plate 146. These stops 154 limit the pivot movement of the flange 143 as upper and lower end faces 153 of the flange 143 abut the upper and lower stops 154 respectively.

The upper trimming cuter 113 has a similar construction so that it can excavate the ground above the frame work 22 of the mining machine upon upward tilting. Specifically, as illustrated in Figure 14, a flange 155 of the bearing device 130 is pivotably connected with a bracket plate 157 mounted on an upper front end portion 156 of the lower frame 25 and a cylinder device 158 is provided to raise the upper trimming cutter 113 beyond the upper surface of the frame work 22 of the mining machine. The upper and lower cylinder devices 147 and 158 are controlled independently so that the mining machine can excavate an upwardly or downwardly directed gate road as desired.

Referring back to Figure 18, an intermediate support bracket 159 is provided at a midpoint of the shaft body 124 of the trimming cutter 113/114. The shaft body 124 extends through the intermediate bracket 159. The intermediate bracket 159 also ,rr has a divisible structure as illustrated in Figure 22. A front half cylindrical segment 160 of the bracket 159 has a plurality of fixed bits 161 on its outer periphery. These fixed bits 161 are directed radially outward. The front half 160 of the intermediate bracket 159 is coupled with a rear half segment 162 by bolts 163. The rear half segment 162 extends rearward like the flange 143 of the bearing device 130 shown in Figure 21 and has a pin 165 near its rear end. The pin 165 is rotatably fitted in a bore formed in a bracket plate 164 mounted on the front plate 145 of the lower frame 25. Therefore, the rear half segment 162 can pivot about the pin 165 together with the front half segment 160. Above the pin 165, provided is a reinforcing rod 166 which penetrates the rear half segment 162 in the width direction of the mining machine. As shown in Figure 21, ends 166a of the reinforcing rod 166 are secured to the flanges 143 of the right and left bearing devices 130. Therefore, the reinforcing rod 166 extends in parallel to the shaft body 124 and connects the intermediate support bracket 159 with the bearing devices 130. It should be noted that the cutter bits 161 are not illustrated in Figure 18.

The upper and lower trimming cutters 113 and 114 having a drum shape can excavate those portions Q of the ground or working face 16 (Figure 2) which the main cutters cannot excavate like the trimming cutters 63 and 64 of the first embodiment.

Since the trimming cutters 113 and 114 of this embodiment have a drum shape and the rotating drum 124 of each trimming cutter 113/114 having a number of cutter bits 125 and 161 contacts the o ~remaining working face Q in a larger area directly, the excavation of the remaining portions Q for formation of the horizontal roof 13 and floor 15 of the gate road 2/3 (Figure 1) can be accomplished more reliably than the saw-shaped trimming cutters 63 and 64. The saw-shaped trimming cutter of the first embodiment contacts the working face linearly. In addition, even if the excavation speed is fast, easy and continuous trimming can be

S

carried out. Other structure and function/operation of the .4 S mining machine of this embodiment are the same as those of the first embodiment.

S

It should be noted that the number of the main cutters is not limited to two: it may be three or more. For example, as shown in Figure 23, three main cutters 171, 172 and 173 having the same structure may be arranged linearly in the width direction of the mining machine. In this case, two upper trimming cutters 174 and two lower trimming cutters 175 are arranged between each two adjacent main cutters. This mining machine can excavate a gate road having a cross section of further elongated oval shape. In Figure 23, the main cutters 171 to 173 include arcuate cutter bits 67 and 68 and the trimming cutters 174 and 175 include saw-shaped ones like those illustrated in Figure 2.

However, the main cutters 111 and 112 and trimming cutters 113 and 114 described in the second embodiment and shown in Figure 13 can be employed.

The frame work 22' of the mining machine shown in Figure 23 may be divided into a plurality of frames 25' to 28' in the circumferential direction of the mining machine and the frames may be moved outwardly or inwardly in the diametrical r direction of the mining machine such that movements of the mining machine in the longitudinal direction of the mining machine can be conducted without any difficulty. How many frames the frame work 22' should be divided into and how much the frames should be moved inward are determined in accordance with the size of the cross section of the gate road 2/3 (Figure 1) and the length of the rock bolts 99 (Figure 1) projecting from the walls ~of the gate road toward the inside of the gate road.

In the foregoing, the frame work 22 are divided into upper, right, left and lower frames 25 to 28 (25' to 28').

I However, the frame work may be divided in a different way: for example, it may be divided into upper right, upper left, lower right and lower left frames or it may be divided into two, three, five, six, seven or eight frames or more. It can be determined arbitrarily as long as the frame work 22 can expand and shrink in the diametrical direction of the mining machine. In foregoing embodiments, the frames 25 to 28 are spaced in the circumferential direction of the mining machine during the excavation as shown in Figure 2 and they have little space between themselves during the shrinking as shown in Figure 3, but they may have little clearance between themselves during the excavation and they may be overlapped partly during the shrinking. It should also be noted that the present invention may be applied to formation of a tunnel.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

r Q:AOPER\SSB\74000-96.SPE 6/5/99 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. An excavation apparatus including: an excavation device for excavating a ground in a predetermined cross section to create a gate road; a frame work for supporting walls of the gate road excavated by the excavation device, the frame work including a plurality of frames divided in its circumferential direction, the excavation device being mounted on a front portion of the frame work, the frame work being divided into front and rear units in the excavation direction and a propelling device being provided therebetween; means for moving at least one of the frames inwardly so °9* that a cross section of the frame work becomes smaller than that of the gate road; and means for bolting rock bolts into the wall of the gate road.

2. The excavation apparatus of claim 1, wherein the moving means-presses the frames of the rear unit against the walls of the gate road to obtain a counterforce from the walls of the gate road when the propelling device pushes the front unit forwardly in the excavation direction.

3. The excavation apparatus of claim 2, wherein the moving means presses the frames of the front unit against the AT T 43

Claims

4. The excavation apparatus of any one of claims 1 to 3, wherein the frame work is divided into an upper frame which supports a top wall of the gate road, right and left side frames which support side walls of the gate road respectively and a C lower frame which contacts a bottom wall of the gate road. 10 5. The excavation apparatus of any one of claims 1 to 4, e, wherein the rear unit includes means for bolting in rock bolts into the walls of the gate road.
6. The excavation apparatus of any one of claims 1 to wherein the excavation device includes a plurality of main cutters juxtaposed at the same height linearly in a single plane in a diametrical direction of the frame work and trimming cutters for excavating those portions of the ground which the main cutters cannot excavate.
7. The excavation apparatus of claim 6, wherein the main cutters are rotary cutters which excavate the ground circularly in a manner such that a plurality of partly overlapping circles juxtaposed in the width direction of the frame work are made in the working face of the ground, and the trimming cutters have a linear shape extending along tangential lines of the partly overlapping circles made by the main cutters.
8. The excavation apparatus of claim 7, wherein each Q: \OPER\SSB\74000-96.SPE 7/5/99 9 9 C C S. of the trimming cutters is a saw-like cutter.
9. The excavation apparatus of claim 6, 7 or 8, wherein each of the main cutters includes a plurality of spokes extending radially from its rotation center shaft and a number of bits mounted on the spokes. The excavation apparatus of claim 9, wherein each spoke is divisible in its longitudinal direction.
11. The excavation apparatus of any one of claims 6 to further including means for moving the trimming cutters inward 10 or outward in the diametrical direction of the frame work.
12. The excavation apparatus of any one of claims 6 to 11 further including means for moving the trimming cutters in the width direction of the frame work.
13. The excavation apparatus of any one of the foregoing claims further including a cover member which is movable forward along the top wall of the gate road from the frame work beyond the excavation device.
14. The excavation apparatus of claim 6, 7, 9, 10, 11 or 13, wherein each of the trimming cutters includes a drum body and a number of bits mounted on the drum body, and the trimming cutters are rotated about their shaft extending in the width direction of the frame work. The excavation apparatus of claim 14, further including a first set of nozzles buried in an outer surface of each trimming cutter for spraying a water toward the ground and/or trimming cutter, a first water passage bored in the drum body and means for supplying the water to the first set of HC.) EK~l RA4 -o~ilTL3 ULIc 0 _9 Q:\OPER\SSB\74000-96.SPE 6/5/99 nozzles through the first water passage.
16. The excavation apparatus of any one of the foregoing claims further including a second set of nozzles buried in an outer surface of the excavation device for spraying a water toward the ground and/or excavation device, a second water passage bored in the excavation device and means for supplying the water to the second set of nozzles through the second water passage. S eS Q:\OPER\SSB\74000-96.SPE 6/5/99
17. An excavation apparatus substantially as hereinbefore described with reference to Figures 1 to 23. DATED this 6th day of May 1999 Ishikawajima-Harima Heavy Industries Co., Ltd By its Patent Attorneys DAVIES COLLISON CAVE ABSTRACT OF THE DISCLOSURE The excavation machine includes an excavation device for excavating a ground in a predetermined cross section to create a gate road tunnel) and a frame work for support- ing walls of the gate road excavated by the excavation device and for supporting the excavation device at its front portion. The frame work includes a plurality of frames divided in its circumferential direction. The excavation machine further in- eludes expansion/retraction Jacks for moving at least one of the frames inwardly so that a cross section of the frame work becomes smaller than that of the gate road. The frame work is also ivided into front and rear units in the excavation direction and a propelling device is provided between the front and rear units. The expansion/retraction jacks press the frames of the rear unit against the walls of the gate road to obtain a counterforce from the walls of the gate road when the propelling device pushes the front unit forwardly in the excavation direction. The expan- sion/retraction jacks press the frames of the front unit against the walls of the gate road to obtain a counterforce from the walls of the gate road when the propelling device pulls the rear unit toward the front unit. Ill