SHIELD TUNNELLING MACHINE

Abstract: A shield tunnelling machine comprises a tubular shield body (12), an excavating cutter assembly (52) disposed on a front end of the body, a partition wall (24) for defining the interior of the body into a front region and a rear region behind the front region, the front region having a first chamber (18) for receiving matter excavated by the cutter assembly and a second chamber (20) communicating to a rear portion of the first chamber so as to receive the excavated matter from the first chamber, the second chamber extending around an axis of the body, a rotor (46) disposed in the first chamber and having an outer diameter gradually increasing toward the rear, a drive mechanism (84) for turning the rotor around a first axis extending in the longitudinal direction of the body and rotating the rotor around a second axis eccentric to the first axis, an annular member (66) mounted to the rotor so as to be turned and rotated together with the rotor in the second chamber and extending around the axis of the body and a discharging mechanism for discharging the excavated matter received in the second chamber from a lower portion of the second chamber to the rear region.

Description: BACKGROUND OF THE INVENTION Field of the Invention: This invention relates to a shield tunnelling machine provided with a rotor turned around a first axis extending in axial direction of a shield body and rotated around a second axis eccentric to the first axis, as described in the first part of claim 1. A shield tunnelling machine of this kind is disclosed in Japanese Patent Disclosures (KOKAI) No. 61-102999 and No. 63-189596. This excavating machine comprises a tubular shield body, a partition wall for defining the interior of the body into a front region and a rear region, a rotor disposed in the front region so as to permit the turning motion around an axis of the body and the rotational motion around an axis displaced from the axis of the body and having the outer surface gradually increasing in diameter toward the rear, a drive mechanism for turning and rotating the rotor, an excavating cutter assembly connected to the rotor so as to be turned and rotated together with the rotor and a discharging mechanism for discharging the excavated matter from the front region to the rear region. The front region has a first chamber having a diameter gradually reducing toward the rear and receiving the matter excavated by the cutter assembly and a second chamber communicating to a rear portion of the first chamber so as to receive the excavated matter from the first chamber and extending around the axis of the body. The rotor has an outer diameter gradually increasing toward the rear and is disposed in the first chamber. In excavation, the rotor and the cutter assembly are turned around the axis of the body and rotated around the axis eccentric to the axis of the body by the drive mechanism. By this, the cutter assembly excavates a facing, and the rotor serves as a machine for compacting and crushing the excavated matter in cooperation with the body. During the excavation, the first and second chambers are filled with the excavated matter, thereby preventing the facing from its collapse. In the tunnelling machine well known per se, however, since pressurized muddy water is supplied from the rear region to the second chamber, as the muddy water and the excavated matter in the second chamber are discharged to the rear region, there is a problem that the disposal of muddy water such as the operation of separating the discharged muddy water and excavated matter from each other should be done. In order to dissolve the problem, when the discharging mechanism provided with a screw conveyor is used in case of excavating the ground containing a large quantity of high viscous matter like a slit layer, the excavated matter is particularly prevented from shifting through the second chamber toward the discharging mechanism due to the viscosity of the excavated matter, so that the excavated matter is not discharged to make the continuance of excavation difficult. SUMMARY OF THE INVENTION It is an object of the present invention to provide a shield tunnelling machine capable of excavating the ground containing a large quantity of high viscous matter without depending on a method using muddy water. A shield tunnelling machine according to the present invention comprises a tubular shield body, an excavating cutter assembly disposed on a front end of the body, a partition wall for defining the interior of the body into a front region and a rear region behind the front region, the front region having a first chamber for receiving the matter excavated by the cutter assembly and a second chamber communicating to a rear portion of the first chamber so as to receive the excavated matter in the first chamber, the second chamber extending around an axis of the body, a rotor disposed in the first chamber and having an outer diameter gradually increasing toward the rear, a drive mechanism for turning or revolving the rotor around a first axis extending in the longitudinal direction of the body and rotating the rotor around a second axis eccentric to the first axis, an annular member mounted to the rotor so as to be turned and rotated together with the rotor in the second chamber and extending around the axis of the body and a mechanism for discharging the excavating matter received in the second chamber from a bottom of the second chamber to the rear region. Due to earth pressure and thrust of the tunnelling machine, the matter excavated by the cutter assembly is received in the first chamber, moved in the first chamber toward the second chamber, shifted from the first chamber to the second chamber, and then moved toward the lower portion of the second chamber. The first chamber is filled with the excavated matter during the excavation, so that the facing is prevented from its collapse. In excavation, since the rotor and the annular member are respectively turned or revolved in the first and second chambers, even if the first and second chambers are filled with the excavated matter, the space for receiving the excavated matter is formed in each of the first and second chambers due to the displacement of the rotor and the annular member relative to the shield body. By this, even if the facing has a silt layer or like layer containing a large quantity of high viscous matter, the excavated matter is mainly received in the first chamber so as to fill the space resulting from the displacement of the rotor and then moved in the first chamber toward the second chamber. The excavated matter in the first chamber is pushed out to the second chamber so as to fill the space resulting from the displacement of the annular member. The excavated matter in the second chamber is shifted toward the lower portion of the second chamber and forcibly pushed out to the lower portion of the second chamber, i.e., a discharging portion, when the annular member is displaced downward, to be finally discharged from the second chamber by the discharging means. Thus, according to the present invention, the ground containing a large quantity of high viscous matter may be excavated without depending on a method using muddy water. A plurality of blades are preferably mounted to the outer surface of the annular member at angular intervals so as to extend in the radial and longitudinal directions of the shield body. By so doing, since the blades are turned and rotated in the second chamber together with the annular member, even the excavated matter with high viscosity in the second chamber is surely shifted to the lower portion of the second chamber with the turning and rotational motions of the blades, so that the excavated matter in the second chamber is surely discharged. The second chamber preferably has an annular upper area communicating to the first chamber so as to receive the excavated matter in the first chamber and extending around the axis of the body and a lower area communicating to a bottom of the upper area so as to receive the excavated matter in the upper area and serving as the lower portion of the second chamber. By this, even the excavated matter with high viscosity in the upper area is surely shifted toward the lower area with the turning and rotational motions of the annular member and forcibly pushed out from the upper area to the lower area when the annular member is displaced downward, so that the excavated matter received in the lower area is surely discharged by the discharging means. As the discharging mechanism, use can be made of a screw conveyor type mechanism provided with a casing opened to the lower area of the second chamber and to a rear end of the casing and extending in the body from the partition wall to the rear thereof, a screw conveyor extending in the casing from the lower area toward a rear end opening of the casing, a rotary mechanism for rotating the screw conveyor and a valve mechanism for opening and closing the rear end opening of the casing. The discharging mechanism is so structured that the rear end opening of the casing is opened by the valve mechanism when pressure in the casing exceeds a predetermined value. If the cutter assembly is mounted to the front end of the rotor, the cutter assembly is turned and rotated together with the rotor. Also, the cutter assembly provided with a plurality of cutter bits can be used and disposed such that a cutting edge of each cutter bit is directed toward the center of the body. The drive mechanism can be provided with a crankshaft supported by the partition wall as being rotatable around the first axis and having an eccentric portion provided at the side of the first chamber, the eccentric portion rotatably supporting the rotor, a rotary mechanism for rotating the crankshaft, an external gear mounted to the partition wall so as to extend around the first axis and an internal gear partially meshing with the external gear and mounted to at least one of the rotor and the annular member so as to extend around the second axis. The shield body can be provided with a tubular head portion having the front region, a tubular tail portion following the head portion, a plurality of jacks respectively having two connecting portions relatively displaced in the axial direction of the tail portion and a connecting body for interconnecting the head portion and the tail portion so that the connecting body permits the head portion and the tail portion to swing and prevents the head portion and the tail portion from relatively displacing in the axial direction of the tail portion. In this case, each of the jacks is connected on one connecting portion to the head portion, while being connected on the other connecting portion to the tail portion. Also, the jacks and the connecting body are disposed around the axis of the tail portion at angular intervals. The shield tunnelling machine according to the present invention further preferablly comprises an indicator for indicating the direction and amount of relative deviation between the head portion and the tail portion. As the indicator, use is made of a well-known indicator provided with a dial plate fixed to one of the head portion and the tail portion and a pointer fixed to the other of the head portion and the tail portion and confronting the dial plate. When the indicator is disposed close to the connecting body, the amount of relative displacement in the direction of the dial plate and the pointer which move close to and any from each other due to the relative deviation between the head portion and the tail portion is reduced, so that the amount of deviation of the head portion relative to the tail portion is accurately grasped. Another shield tunnelling machine according to the present invention comprises a tubular shield body, an excavating cutter assembly disposed on a front end of the body, a partition wall for defining the interior of the body into a front region and a rear region behind the front region, the front region having a first chamber for receiving the matter excavated by the cutter assembly and a second chamber communicating to a rear portion of the first chamber so as to receive the excavated matter in the first chamber, the second chamber extending around an axis of the body, a rotor disposed in the first chamber and having an outer diameter gradually increasing toward the rear, a drive mechanism for turning the rotor around a first axis extending in the longitudinal direction of the body and rotating the rotor around a second axis eccentric to the first axis, a plurality of blades mounted to the rotor around the axis of the body at angular intervals so as to extend in the radial and longitudinal directions of the body in the second chamber and a mechanism for discharging the excavating matter received in the second chamber from a lower portion of the second chamber to the rear region. In another shield tunnelling machine, the blades are turned and rotated in the second chamber with the turning and rotational motions of the rotor. By this, the excavated matter in the second chamber is shifted to the lower portion of the second chamber by the turning and rotational motions of the blades and finally discharged to the rear region by the discharging means. In another shield tunnelling machine, an annular member extending in the second chamber around the axis of the body is mounted to the rotor so that the annular member is rotated and turned together with the rotor. The blades are mounted to the outer surface of the annular member. By this, the excavated matter in the second chamber is forcibly pushed out downward in the second chamber by the turning motion of the annular member. The foregoing and other objects and features of the invention will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which: Fig. 1 is a sectional view showing an embodiment of a shield tunnelling machine according to the present invention; Fig. 2 is a sectional view taken along a line 2-2 in Fig. 1; Fig. 3 is a left side view showing the embodiment of Fig. 1; Fig. 4 is a sectional view taken along a line 4-4 in Fig. 1; Fig. 5 is an enlarged-scale sectional view showing a portion of a mechanical seal; Fig. 6 is an enlarged-scale sectional view showing a portion of a discharging mechanism; and Fig. 7 is a sectional view taken along a line 7-7 in Fig. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Fig. 1, a shield tunnelling machine 10 comprises a tubular shield body 12. The shield body 12 is provided with a tubular head portion 14 and a tail portion 16 following the head portion. A front end of the tail portion 16 is formed into a small-diameter portion and swingably received inside a rear end of the head portion 14. The head portion 14 is divided into a first tubular portion 14a having a first chamber 18 of a truncated conical shape having an inner diameter gradually reducing toward the rear and a second tubular portion 14b defining a second chamber 20 following the rear of the first chamber 18 and having an inner diameter larger than that of a rear end of the first chamber. The first and second tubular portions 14a and 14b are separably jointed to each other with a plurality of bolts 22 such that a rear end of the first tubular portion 14a and a front end of the second tubular portion 14b are butted against each other. The first and second chambers 18 and 20 constitute a front region maintained at high pressure so as to prevent a facing from its collapse and are defined against a rear region under atmospheric pressure by a partition wall 24 mounted to the second tubular portion 14b. The inner diameter of the first chamber 18 may be approximately equalized. In this case, the inner diameter of the first chamber may be made approximately equal to that of the second chamber, and the inner diameter of the second chamber may be made smaller than that of the first chamber. The partition wall 24 has a central portion provided with a boss portion 26 projecting toward the second chamber 20 and an outer peripheral portion provided with a projection 28 projecting toward the second chamber 20. As shown in Fig. 2, the projection 28 takes the shape of a ring having a cut-out lower portion. Thus, the second chamber 20 has an annular upper area 20a extending around the boss portion 26 and a lower area 20b communicated with a bottom of the upper area 20a so as to receive excavated matter from the upper area. The upper area 20a is communicated with the first chamber 18 so as to receive excavated matter from the first chamber 18. The boss portion 26 of the partition wall 24 supports a crankshaft 32 extending toward an axis 30 of the body 12 so that the crankshaft 32 is rotated around the axis 30 through a plurality of bearings 34. The crankshaft 32 is provided with a supported portion 32a supported by the boss portion 26, an eccentric portion 32b extending forward from the supported portion 32a and an extension portion 32c extending rearward from the supported portion 32a. The extension portion 32c is supported, through a plurality of bearings 38, on a bracket 36 mounted to the partition wall 24. An axis of the supported portion 32a and that of the extension portion 32c are made coincident with the axis 30 of the shield body 12, whereas an axis 40 of the eccentric portion 32b is made eccentric to the axis 30 by a distance "e". Each bearing 34 is prevented from shifting toward the axis 30 by a bearing holder 42 fitted to a front end of the boss portion 26 and a gear 44 mounted to an end of the extension portion 32c at the side of the supported portion 32a. The eccentric portion 32b rotatably supports a rotor 46 disposed inside the first chamber 18 through a plurality of bearings 48. The rotor 46 has the outer surface gradually increasing in diameter toward its rear end. By this, the first chamber 18 is limited in shape to a substantially V-like sectional shape converging toward the second chamber 20. The rotor 46 is prevented from getting out of the crankshaft 32 by a nut 50 screwed onto a front end of the crankshaft 32. As shown in Figs. 1 and 2, the outer diameter of a rear end of the rotor 46 is selectively defined as such a value that the first and second chambers 18 and 20 always communicate to whole annular range around the axis 30. A cutter assembly 52 is fixedly attached to a front end of the rotor 46. As shown in Figs. 1 and 3, the cutter assembly 52 is provided with a plurality of arms 54 extending from the rotor 46 in the radial direction of the body 12, a ring 56 for interconnecting front ends of the adjacent arms 54, a disk-like cap 58 mounted to the front end of the rotor 46, a plurality of cutter bits 60 fixed to the arm 54, a plurality of cutter bits 62 mounted to the ring 56, and a plurality of cutter bits 64 mounted to the cap 58. Each cutter bit 60 mounted to the arms 54 is disposed such that its cutting edge is directed toward the rotary center of the cutter assembly 52, that is, directed inward, while its cutting edge is positioned behind the cutting edge of the cutter bit disposed outside the first-mentioned cutter bit. On the other hand, each cutter bit 62 disposed on the outermost periphery has an inward cutting edge directed toward the rotary center of the cutter assembly 52 and an outward cutting edge directed in the opposite direction to the rotary center. Also, each cutter bit 64 mounted to the cap 58 is disposed such that its cutting edge is directed outward in the radial direction. As shown in Figs. 1 and 2, an annular member 66 is mounted to the rear end of the rotor 46. The annular member 66 is disposed in the second chamber 20 and extends around the boss portion 26 as being spaced apart from the boss portion 26. The annular member 66 may be a portion of the rotor 46. An internal gear 68 centering around the axis 32 is mounted to the inside of the annular member 66. An external gear 70 meshing with the gear 68 is mounted to the boss portion 26 as centering around the axis 30. The radius of tooth tip of each of the gears 68 and 70 is selectively defined as such a value that both gears partially mesh at a portion in the circumferential direction with each other. The internal gear 68 may be integral with the annular member 66. Also, the internal gear 68 may be directly mounted to the rotor 46, instead of fixing the internal gear 68 to the annular member 66. Further, the external gear 70 may be mounted to the boss portion 26, and the internal gear 68 may be mounted to the rotor 46. A portion between the partition wall 24 and the annular member 66 is maintained into liquid-tightness by a mechanical seal 72. As shown in Figs. 1 and 5, the mechanical seal 72 is provided with a ring 74 immovably disposed in a recess formed on the rear end face of the annular member 66 and that of the internal gear 68 and a ring 76 disposed inside an annular projection formed on the partition wall 24 at the second chamber side so that the ring 76 is immovable in the diametral direction of the body 12. The ring 76 is pressed against the ring 74 by the action of a plurality of springs 78 disposed on the partition wall 24. Each spring 78 is received in a recess formed on the partition wall 24. As shown in Figs. 1 and 2, a plurality of blades 80 are mounted to the outer peripheral surface of the annular member 66 at equally angular intervals, and a plurality of rod-like members 82 are mounted to the rear end face of the rotor 46 at equally angular intervals. Each blade 80 extends back and forth and also extends from the annular member 66 outward in the radial direction of the body 12 to a position beyond a communicating portion between the first and second chambers 18 and 20. On the other hand, each rod-like member 82 extends from the rotor 36 outward in the radial direction of the body 12 to a position beyond the communicating portion between the first and second chambers 18 and 20. Each blade 80 may be directly mounted to the rotor 46. The crankshaft 32 is rotated through the gear 44 by a pair of rotary mechanisms 84 mounted to the bracket 36. By this, since the rotor 46 is revolved around the axis 30, the cutter assembly 52, the annular member 66, the internal gear 68, the blades 80 and the rod-like members 82 are revolved around the axis 30, respectively. When the internal gear 68 is revolved, a mesh portion between the internal gear 68 and the external gear 70 varies with the revolving of the internal gear 68, so that the internal gear 68 is rotated around the axis 40 relative to the external gear 70. By this, the rotor 46, the cutter assembly 52, the annular member 66, the blades 80 and the rod-like members 82 are not only revolved around the axis 30, but also rotated around the axis 40. In the illustrated embodiment, the rotational direction of the rotor 46, the cutter assembly 52, the annular member 66, the internal gear 68, the blades 80 and the rod-like members 82 is identical with the revolving direction, since the internal gear 68 is mounted to the side of the rotor 46, and the external gear 70 is mounted to the side of the partition wall 24. However, if the internal gear is mounted to the side of the partition wall, and the external gear is mounted to the side of the rotor, the rotational direction is made reverse to the revolving direction. The ratio of the revolving motion to the rotational motion of the rotor 46, the cutter assembly 52, the annular member 66, the internal gear 68, the blades 80 and the rod-like members 82 is determined depending on the number of the teeth of the gear 68 and that of the gear 70. If a difference in number of teeth between the gears 68 and 70 is made small, the number of times of the revolving motion per one time of rotational motion is increased. In the illustrated embodiment, the tail portion 16 is also divided into first and second tubular portions 16a and 16b separably butted and jointed to each other with a plurality of bolts 86. As shown in Figs. 1 and 4, the head portion 14 and the tail portion 16 are swingably interconnected through a rod 88 and three jacks 90, 92 and 94 for correcting the direction of the head portion 14 relative to the tail portion 16 to correct the direction of excavation. Each of the jacks 90, 92 and 94 is a double-acting jack capable of operating either in pushing and pulling manners. One end of the rod 88 and cylinders of the jacks 90, 92 and 94 are respectively connected to the head portion 14 through a joint 96. On the other hand, the other end of the rod 88 and piston rods the jacks 90, 92 and 94 are respectively connected to the tail portion 16 through a joint 98. The cylinders of the jacks 90, 92 and 94 may be connected to the tail portion 16, and the piston rods of the jacks 90, 92 and 94 may be connected to the head portion 14. Each of the joints 96 and 98 preferably use a universal joint which permits connected members to angularly rotate around two axes orthogonal to the axis of the corresponding rod or the axes of the jacks. As such joint, use may be made of a connecting structure, i.e., a joint disclosed in Japanese Patent Publication No. 61-47956, for example. The rod 88 and the jacks 90, 92 and 94 have their axes disposed on an imaginary circle around the axis 30 at equally angular intervals (90 degrees). In the illustrated embodiment, the rod 88 and the jacks 90, 92 and 94 are so disposed that the rod 88 and the jack 90 are respectively located above the jacks 94 and 92. Otherwise, the rod 88 and the jacks 90, 92 and 94 may be so disposed that the rod 88 occupies the position of the jack 90, 92 or 94. In correction, when the jacks 92 and 94 are simultaneously contracted, the head portion 14 is directed downward relative to the tail portion 16 with the rod 88 and the jack 90 as the center. When the jacks 92 and 94 are simultaneously extended, the head portion 14 is directed upward relative to the portion 16 with the rod 88 and the jack 90 as the center. On the other hand, when the jacks 90 and 92 are simultaneously contracted, the head portion 14 is directed leftward relative to the tail portion 16 with the rod 88 and the jack 94 as the center. When the jacks 90 and 92 are simultaneously extended, the head portion 14 is directed rightward relative to the tail portion 16 with the rod 88 and the jack 94 as the center. As shown in Figs. 1, 4, 6 and 7, a discharging mechanism 100 for discharging the excavated matter from the second chamber 20 is provided with a casing 102 opening to the lower portion of the second chamber 20, i.e., to the lower area 20b and extending from the partition wall 24 rearward within the body 12, a screw conveyor 104 extending in the casing 102 toward the rear end opening of the casing, a drive mechanism 106 for rotating the screw conveyor and a valve mechanism 108 for opening and closing the rear end opening of the casing 102. A front end of the screw conveyor 104 reaches the lower area 20b of the second chamber 20. The screw conveyor 104 is supported on its front end by the partition wall 24 while being supported on its rear end by a cap 110 mounted to the bracket 36. A shaft 112 extending from the rear end of the screw conveyor 104 rearward is connected to the screw conveyor 104. The shaft 112 extends through a chute 114 mounted to the rear end of the casing 102 and a sleeve 116 mounted to a rear end of the chute and is rotatably supported to the sleeve 116 through a plurality of bearings 118. The chute 114 is opened to the underside and to the side of the casing 102 so that the chute 114 receives the excavated matter discharged by the screw conveyor 104 from the casing 102 to drop the excavated matter downward. A front end opening of the sleeve 116 is closed by a cap 120. The rotational speed of a rotary source 122 is reduced by a reduction gear 124. The drive mechanism 106 transmits the resultant rotation of the rotary source 122 from a sprocket 126 mounted to an output shaft of the reduction gear 124 to a sprocket 128 mounted to a rear end of the shaft 112 through a chain 130 to rotate the screw conveyor 104. The drive mechanism 106 is supported by a case 132 mounted to the sleeve 116. The case 132 has a rearward opening which is closed by a plate 134. The valve mechanism 108 is provided with a valve seat 136 mounted to the rear end of the casing 102 by the chute 114, a valve body 138 slidably supported by the shaft 112 and a pair of cylinder mechanisms 140 for pressing the valve body toward the valve seat 136. The valve body 138 has the outer surface gradually increasing in diameter toward that rear. In excavation, the tunnelling machine 10 is advanced by a basic thrusting device installed in a shaft (not shown) together with a pipe 143 following the rear of the shield body 12. When the tunnelling machine 10 is advanced, the crankshaft 32 is rotated by the rotary mechanism 84, so that the rotor 46, the cutter assembly 52, the annular member 66, the internal gear 68, the blades 80 and the rod-like members 82 are revolved around the axis 30, while being rotated around the axis 40. Thus, the facing is excavated by the revolving motion and the rotational motion of the cutter assembly 52, and the first and second chambers 18 and 20 are filled with the excavated matter, so that the facing is prevented from its collapse. However, during the excavation, since the rotor 46 and the annular member 66 are revolved, the space is defined inside each of the first and second chambers 18 and 20 due to the displacement of the rotor 46 and the annular member 66 relative to the body 12, even if the first and second chambers 18 and 20 are filled with the excavated matter. By this, the excavated matter is transferred to the first chamber 18 by the advancing force of the excavating machine and the earth pressure of the facing so as to fill the space resulting from the displacement of the rotor 46 and then shifted through the first chamber 18 toward the second chamber 20. Also, the excavated matter within the first chamber 18 is pushed out to the upper area 20a of the second chamber 20 so as to fill the space resulting from the displacement of the annular member 66. The excavating matter within the second chamber 20 is repetitively pressed radially outward within the upper area 20a of the second chamber 20 along with the revolving motion of the annular member 66, while being shifted gradually downward through the upper area 20a, i.e., to an upper portion of the lower area 20b along with the rotational motion of the annular member 66 and the blades 80, so that the excavated matter is forcibly depressed to the lower areas 20b there when the annular member 66 is displaced downward along with its revolving motion. The excavated matter within the lower area 20b is conveyed toward the valve mechanism 108 by the screw conveyor 104 of the discharging mechanism 100. However, since the rear end of the casing 102 is closed by the valve mechanism 108, the excavated matter stays within the casing 102. By this, the facing is more surely prevented from its collapse. When the valve body 138 of the valve mechanism 108 is pushed rearward by the excavated matter within the casing 102 against the force of the cylinder mechanims 140, the valve body 138 is separated from the valve seat 136, so that the excavated matter within the casing 102 is pushed out of the casing 102 to the chute 114. The excavated matter dropping from the chute 114 is received by a belt conveyor 142 and conveyed rearward by the belt conveyor. The earth pressure of the facing mainly acts on the first tubular portion 14a and the rotor 46. The earth pressure acting on the rotor 46 acts on an earth pressure detector 144 through the crankshaft 132. The earth pressure detector 144 is disposed on the extension portion 32c of the crankshaft 32 through a plurality of bearings 146 and defines an earth pressure detecting chamber together with the inner face of the rear end of the bracket 36 and the front end face of the cap 110. The earth pressure detecting chamber transmits the pressure acting on fluid received in the earth pressure detecting chamber to an indicator 150 through a pipe 148. By this, the earth pressure is indicated visually on an indicating portion for an earth pressure cell of the indicator 150. As shown in Fig. 4, the indicator 150 is provided with a dial plate 152 for indicating the direction and amount of deviation of the head portion 14 relative to the tail portion 16 and a pointer 154 confronting the dial plate, in addition to instruments such as an earth pressure cell and an oil pressure gauge. The dial plate 152 uses a well-known dial plate having a plurality of parallels and meridians. The pointer 154 also uses a well-known cross-shaped pointer. The indicator 150 is mounted on the tail portion 16 such that the indicating surface of the indicator is located in the rear. When the head portion 14 is in its neutral position relative to the tail portion 16, that is, when the head portion 14 is not deviated from the tail portion 16, the pointer 154 is mounted to the cap 110 with a fixture 156 such that the pointer 154 indicates the reference point, i.e., 0 of the dial plate 152. When the head portion 14 is deviated relative to the tail portion 16 by the direction correcting device consisting of the rod 88 and the jacks 90, 92 and 94, the pointer 154 is displaced relative to the dial plate 152 in the direction corresponding to the deviation by a distance corresponding to the amount of diviation. The positional relation between the dial plate 152 and the pointer 154 is displayed on a monitor (not shown) by a television camera 158 for picking up the indicating surface of the indicator 150. The television camera 158 is also mounted to the tail portion 16. The indicator 150 including the dial plate 152 and the pointer 154 is preferably disposed close to the rod 88 in a plane orthogonal to the axis 30. By so doing, since the displacement of the pointer 154 in the direction of the dial plate 152 and the pointer 154 which move close to and away from each other is small, the amount of deviation of the head portion 14 relative to the tail portion 16 is accurately indicated. Also, when the indicator 150 is disposed on a fulcrum of relative swing of the head portion 14 and the tail portion 16, e.g., on center of circular arc around the center in the axial direction of the rod 88, the displacement of the pointer 154 in the direction of the dial plate 152 and the pointer 154 which move close to and away from each other is smaller, so that the amount of deivation of the head portion 14 relative to the tail portion 16 is more accurately indicated. The tunnelling machine 10 has a hole 160 formed in an upper portion of the partition wall 24. The hole 160 is closed by a plate 162 when the excavated matter is discharged by the discharging mechanism 100. The hole 160 is utilized when muddy water is used for discharging means. When the muddy water is used for the discharging means, the discharging mechanism 100 and the plate 162 are removed, and a pressurized muddy water supplying pipe is connected to the hole 160, an a muddy water draining pipe is connected in place of the discharging mechanism 100, i.e., communicated with the lower area 20b.

Claims: A shield tunnelling machine, comprising: a tubular shield body (12); an excavating cutter assembly (52) disposed on a front end of said body; a partition wall (24) for defining the interior of said body into a front region and a rear region behind said front region, said front region having a first chamber (18) for receiving matter excavated by said cutter assembly and a second chamber (20) communicating to a rear portion of said first chamber so as to receive the excavated matter from said first chamber, said second chamber extending around an axis of said body; a rotor (46) disposed in said first chamber and having an outer diameter gradually increasing toward the rear; a drive mechanism (84) for turning said rotor around a first axis extending in the longitudinal direction of said body and rotating said rotor around a second axis eccentric to said first axis; and a discharging mechanism (100) for discharging the excavated matter received in said second chamber from a lower portion of said second chamber to said rear region, characterised in an annular member (66) mounted to said rotor so as to be turned and rotated together with said rotor in said second chamber and extending around the axis of said body; and a plurality of blades (80) mounted on the outer surface of said annular member (66) at angular intervals so as to extend in the radial and longitudinal directions of said body, in said second chamber. A shield tunnelling machine according to claim 1, wherein said second chamber (20) has an annular upper area (20b) communicating to said first chamber (18) so as to receive the excavated matter from said first chamber and extending around the axis of said body (12) and a lower area (20b) communicating to a bottom of said upper area so as to receive the excavated matter from said upper area and serving as said lower portion of said second chamber, and said discharging mechanism (100) discharges the excavated matter received in said lower area. A shield tunnelling machine according to claim 2, wherein said discharging mechanism (100) is provided with a casing (102) opened to said lower area (20b) and to a rear end thereof and extending in said body (12) from said partition wall (24) toward the rear, a screw conveyor (104) extending in said casing from said lower area toward a rear end opening of said casing, a rotary mechanism (106) for rotating said screw conveyor and a valve mechanism (108) for opening and closing said rear end opening and opening said rear end opening when pressure in said casing exceeds a predetermined value. A shield tunnelling machine according to claim 1, wherein said cutter assembly (52) is mounted to a front end of said rotor (46) and provided with a plurality of cutter bits (60) having cutting edges respectively directed toward the center of said body. A shield tunnelling machine according to claim 1, wherein said drive mechanism is provided with a crankshaft (32) supported by said partition wall (24) as being rotatable around said first axis and having an eccentric portion (32b) provided at the side of said first chamber (18), said eccentric portion rotatably supporting said rotor (46), a rotary mechanism (84) for rotating said crankshaft, an external gear (70) mounted to said partition wall so as to extend around said first axis and an internal gear (68) partially meshing with said external gear and mounted to at least one of said rotor and said annular member so as to extending around said second axis. A shield tunnelling machine according to claim 1, wherein said shield body (12) is provided with a tubular head portion (14) having said front region, a tubular tail portion (16) following said head portion, a plurality of jacks (90,92,94) having two connecting portions relatively displaced in the axial direction of said tail portion, and a connecting body (88) for interconnecting said head portion and said tail portion so that said connecting body permits said head portion and said tail portion to swing, and prevents said head portion and said tail portion from relatively displacing in the axial direction of said tail portion, each of said jacks being connected at one connecting portion to said head portion, while being connected at the other connecting portion to said tail portion, and said jacks and said connecting body being disposed around the axis of said tail portion at angular intervals. A shield tunnelling machine according to claim 6, further comprising an indicator (150) disposed close to said connecting body (88) and indicating the direction and amount of relative deviation between said head portion and said tail portion, said indicator including a dial plate (152) fixed to one of said head portion and said tail portion and a pointer (154) fixed to the other of said head portion and said tail portion and confronting said dial plate.

Inventors: AKESAKA, TOSHIO
Applicants: KABUSHIKI KAISHA ISEKI KAIHATSU KOKI
Application year: 1990
Main classification: E21D9
IPC codes: E21D9, E21B7