DIRECTION CORRECTING DEVICE FOR SHIELD TUNNELLING MACHINE

Abstract: A direction correcting device for a shield tunnelling machine having a shield body (12) provided with a head portion (14) and a tail portion (16) following the head portion is adapted to correct the direction of the head portion relative to the tail portion. The device comprises three jacks (38,40,42) respectively having two connecting portions relatively displaced in the axial direction of the tail portion, and a connecting body (36) for interconnecting the head portion and the tail portion so as to permit the head portion and the tail portion to swing, while preventing the head portion and the tail portion from relatively displacing in the axial direction of the tail portion. Each of the jacks is connected at one connecting portion to the head portion, while being connected at the other connecting portion to the tail portion, and the jacks and the connecting body are disposed around the axis of the tail portion at angular intervals.

Description: BACKGROUND OF THE INVENTION Field of the Invention: This invention relates to a direction correcting device for a shield tunnelling machine using a shield body provided with a head portion and a tail portion following the head portion and, more particularly, to a device for correcting the excavating direction by correcting the direction of the head portion relative to the tail portion as described in the first part of claim 1; (prior art see AU-B-35792/78). Furthermore the Japanese Publication No. 61-23356 discloses a direction correcting device for a shield tunnelling machine using four double-acting hydraulic jacks disposed around the axis of a tail portion at equally angular intervals and respectively having one ends connected to a head portion and the other ends connected to the tail portion. In the direction correcting device well known per se, four jacks are divided into one set of jacks disposed above the horizontal line passing through the axis of the tail portion and the other set of jacks disposed below the above-mentioned horizontal line. When the one set of jacks are respectively extended (or contracted) and the other set of jacks are respectively contracted (or extended), the head portion is corrected as being directed upward (or downward) relative to the tail portion. On the other hand, the four jacks are divided into one set of jacks disposed leftward relative to the vertical line passing through the axis of the tail portion and the other set of jacks disposed rightward relative to the above-mentioned vertical. When the one set of jacks are respectively extended (or contracted) and the other set of jacks are respectively contracted (or extended), the head portion is corrected as being directed leftward (or rightward) relative to the tail portion. As another direction correcting device, Japanese Patent Publication No. 61-47956 discloses a device using a rod having one end connected to a head portion and the other end connected to a tail portion and disposed on the vertical line orthogonal to the axis of the tail portion, and two hydraulic jacks respectively having one ends connected to the head portion and the other ends connected to the tail portion and disposed symmetrically about the above-mentioned vertical line. In the direction correcting device will known per se, when both jacks are respectively extended or contacted, the head portion is corrected as being directed upward or downward relative to the tail portion. On the other hand, when one jack is extended and the other jack is contracted, the head portion is corrected as being directed leftward or rightward relative to the tail portion. However, since the direction correcting device disclosed in Japanese Patent Publication No. 61-23356 requires four jacks, the structure such as a piping for fluid for operating the jacks is complicated. Also, in the direction correcting device disclosed in Japanese Patent Publication No. 61-47956, since the rod and two jacks receive loads acting on the head portion and the tail portion in advancing and in correction of the direction, large-sized jacks are needed. SUMMARY OF THE INVENTION It is an object of the present invention to provide a direction correcting device for a shield tunnelling machine, which does not need any large-sized jacks and has a simple structure. A direction correcting device according to the present invention for correcting a shield body which is provided with a head portion and a tail portion following the head portion is adapted to the direction of the head portion relative to the tail portion. The device comprises three 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 as to permit the head portion and the tail portion to swing, while preventing the head portion and the tail portion from relatively displacing in the axial direction of the tail portion, each of the jacks being connected at one connecting portion to the head portion, while being connected at the other connecting portion to the tail portion, and the jacks and the connecting body being disposed around the axis of the tail portion at angular intervals. When one of two jacks adjacent to the connecting body and the jack not adjacent to the connecting body are extended or contracted together, the head portion is corrected as being directed upward or downward relative to the tail portion. On the other hand, when the other one of two jacks adjacent to the connecting body and the jack not adjacent to the connecting body are extended or contracted together, the head portion is corrected as being directed leftward or rightward relative to the tail portion. The direction correcting device according to the present invention requires only three jacks in number, so that a structure such as a piping for fluid for operating the jacks is simplified in comparison with the prior art device using four jacks. Also, since the load between the head portion and the tail portion acts on the connecting body and two jacks, the direction correcting device according to the present invention may use smaller-sized jacks in comparison with the prior art device using one connecting body and two jacks. The jacks and the connecting body are preferably disposed on an imaginary circle around the axis of the tail portion at equally angular intervals. Thus, by equalizing the extended and contracted amounts of both jacks when the head portion is corrected vertically relative to the tail portion to those of both jacks when the head portion is corrected leftward or rightward relative to the tail portion, the correcting amount in the vertical direction is made equal to that in the leftward or rightward direction. The connecting body may include a rod having two connecting portions incapable of the relative displacement in the axial direction of the tail portion and respectively connected at one connecting portion to the head portion while being connected at the other connecting portion to the tail portion. As each of the jacks, use is made of a double-acting hydraulic jack having two liquid chambers defined by a piston sliding within a cylinder. Further, the direction correcting device according to the present invention comprises a pump for supplying pressurized fluid to the jacks in order to operate the jacks, a solenoid operated change-over valve corresponding to each of the jacks and disposed between the corresponding jack and the pump to change over flow paths for the pressurized fluid, each of the flow paths being individually connected to the liquid chamber, a control circuit for controlling current applied to the change-over valves, and a check valve disposed in each of the flow paths and permitting the pressurized fluid to be supplied to the corresponding liquid chamber, while preventing the pressurized fluid from flowing out of the corresponding liquid chamber, the check valve also permitting the pressurized fluid to flow out of the corresponding liquid chamber when pressure acts on the other flow path paired with the above-mentioned flow path. When each of the change-over valves corresponding to the jacks adjacent to the connecting body uses a P-port block type valve, and the change-over valve corresponding to the remaining jack uses an open center type three-positions and four-ports valve, the open center type valve serves as an unloading valve when each jack is in its neutral position, so that the pump is always operated without hindering the normal operation of each jack and without using the unloading valve. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects and features of the invention will become apparent from the following description of a preferred embodiment 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 provided with a direction correcting device according to the present invention; Fig. 2 shows the positional relationship between a rod and jacks as viewed from the rear of the shield tunnelling machine; Fig. 3 is a circuit diagram showing an embodiment of a fluid circuit; and Fig. 4 is a circuit diagram showing an embodiment of a control circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figs. 1 and 2, a shield tunnelling machine 10 comprises a shield body 12 divided into a cylindrical head portion 14 and a cylindrical tail portion 16 connected to the rear of the head portion through a direction correcting device according to the present invention. The internal space of the head portion 14 is defined by a partition wall 18 into a facing-side front region of the partition wall and a rear region of the partition wall communicating to the internal space of the tail portion 16. The shield body 12 receives a thrust from a thrusting device (not shown) installed in a shaft (not shown) through a pipe 20 following the tail portion 16. By this, the shield body 12 is advanced together with the pipe 20. However, in case of applying the direction correcting device according to the present invention to a large-sized shield tunnelling machine, the thrust of the shield body is given by a plurality of jacks, in which a lining built up in the rear of the shield body serves as a reaction body. The shield tunnelling machine 10 is used for a pipe propulsion engineering method for thrusting a pipe while excavating a facing. Thus, the shield tunnelling machine 10 further comprises a cutter assembly 22 for excavating the facing. The direction correcting device according to the present invention may be also applied to the shield tunnelling machine for the pipe propulsion engineering method without using the cutter assembly 22. The cutter assembly 22 is disposed in the front region of the partition wall and supported by the partition wall 18 so that the cutter assembly 22 is rotated around the axis of the head portion 14. The cutter assembly 22 is rotated by a rotary mechanism 24 mounted to the partition wall 18 to excavate the facing. The rotary mechanism 24 is provided with a rotary source 26 like a motor and a reduction gear 28 connected to an output shaft of the rotary source and the cutter assembly 22. A muddy water supply pipe 30 and a drain pipe 32 which are opened to the front region of the partition wall are mounted to the partition wall 18. Earth and sand excavated by the cutter assembly 20 are drained to the rear of the shield tunnelling machine 10 through the drain pipe 32 together with muddy water supplied from the supply pipe 30 to the front region of the partition wall, while preventing the facing from the collapse due to pressure in the front region of the partition wall. 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. A plurality of annular seal members 34 are disposed between the outer periphery of the rear end of the head portion 14 and the inner periphery of the front end of the tail portion 16. By this, the liquid tightness between the head portion 14 and the tail portion 16 is maintained. The direction correcting device for swinging the head portion 14 to the tail portion 16 comprises a rod 36 and three jacks 38, 40 and 42 having the same shape and the same dimension. A front end of the rod 36 is connected to a third connecting portion a bracket 44 provided on the head portion 14 through a joint 46 so that the front end of the rod 36 is rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the head portion 14. On the other hand, a rear end of the rod 36 is connected to a fourth connecting portion a bracket 48 provided on the tail portion 16 through a universal joint 50 so that the rear end of the rod 36 is rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the tail portion 16 and around the axis extending in the vertical direction. By this, the head portion 14 is made swingable relative to the tail portion 16, whereas the head portion is prevented from the displacement in the axial direction of the tail portion 16 relative to the tail portion 16. However, the front end of the rod 36 and the head portion 14 may be interconnected so as to be rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the head portion and also around the axis extending in the vertical direction, and the rear end of the rod 36 and the tail portion 16 may be interconnected so as to be rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the tail portion. Also, as the joint for interconnecting the front end of the rod 36 and the head portion 14 and the joint for interconnecting the rear end of the rod 36 and the tail portion 16, use may be made of a universal joint for interconnecting two members so as to be rotated around two axes orthogonal to each other. Further, the head portion 14 and the tail portion 16 may be directly interconnected through the universal joint so as to be rotated around two axes orthogonal to each other. Each of the jacks 38, 40 and 42, as shown by one of the jacks in Fig. 1, is a double-acting jack having two liquid chambers defined by a piston 54 sliding within a cylinder 52, that is, a jack which permits a rod 56 to operatively push and pull. A hydraulic jack is preferably used for the jacks 38, 40 and 42, or a pneumatic jack and other jacks may be used. As shown by one of the jacks 38, 40 and 42 in Fig. 1, a front end (the cylinder 52 in the illustrated embodiment) of each jack is connected to a first connecting portion a bracket 58 provided on the head portion 14 through a joint 60 so that the front end of each jack is rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the head portion 14. On the other hand, a rear end (the rod 56 in the illustrated embodiment) of each jack is connected to a second connecting portion a bracket 62 provided on the tail portion 16 through a universal joint 64 so that the rear end of each jack is rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the tail portion 16 and around the axis extending in the vertical direction. However, the front end of each jack and the head portion 14 may be interconnected so as to be rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the head portion and around the axis extending in the vertical direction, and the rear end of each jack and the tail portion 16 may be interconnected so as to be rotated around the axis extending in the horizontal direction orthogonal to the axial direction of the tail portion. Also, as the joint for interconnecting the front end of each jack and the head portion 14 and the joint for interconnecting the rear end of each jack and the tail portion 16, use may be made of a universal joint for interconnecting two members so as to be rotated around two axes orthogonal to each other. As the universal joint for interconnecting the rod 36 and the head portion 14 or the tail portion 16 and the universal joint for interconnecting the jacks 38, 40 and 42 and the head portion 14 or the tail portion 16, use may be made of another connecting structure, for example, a joint disclosed in Japanese Patent Publication No. 61-47956, for example. As shown in Fig. 2, the rod 36 and the jacks 38, 40 and 42 are disposed around the axis of the tail portion 16 at equally angular intervals (90 degrees) so that their axes are positioned on an imaginary circle 65 coaxial with the axis of the tail portion 16. In the illustrated embodiment, the rod 36 and the jacks 38, 40 and 42 are so disposed that the rod 36 and the jack 38 are respectively positioned below the jacks 42 and 40. However, the rod 36 may be disposed in any of positions of the jacks 38, 40 and 42. Also, the rod 36 and the jacks 38, 40 and 42 may be so disposed that the rod 36 and the jack 38 are respectively positioned upward, leftward or rightward of the jacks 42 and 40. When the jacks 40 and 42 are simultaneously contracted, the head portion 14 is directed upward relative to the tail portion 16. When the jacks 40 and 42 are simultaneously extended, the head portion 14 is directed downward relative to the tail portion 16. On the other hand, when the jacks 38 and 40 are simultaneously contracted, the head portion 14 is directed leftward relative to the tail portion 16. When the jacks 40 and 42 are simultaneously extended, the head portion 14 is directed rightward relative to the tail portion 16. A load acting between the head portion and the tail portion in correction of the direction and in advancing is dispersed in the rod 36 and the jacks 38, 40 and 42. Thus, by the use of one rod and three jacks, smaller-sized jacks may be used in comparison with the prior art device using one rod and two jacks, and the equipment such as a piping for pressure fluid, i.e., working fluid is more simplified in comparison with the prior art device using four jacks. By equalizing the extended and contracted amounts of the jacks 40 and 42 when the head portion 14 is corrected vertically relative to the tail portion 16 to those of the jacks 38 and 40 when the head portion 14 is corrected leftward or rightward relative to the tail portion 16, the correcting amount in the vertical direction and that in the leftwad or rightward direction are equalized to each other. Therefore, if one rod and three jacks are disposed at equally angular intervals, the correcting operation is facilitated. In the prior art device using one rod and two jacks, the leftward or rightward correction is performed by extending one jack and contracting the other jack, and the upward or downward correction is performed by simultaneously extending or contracting both jacks, so that when the extended and contracted amounts of both jacks are set to be equal to each other, the upward or downward correcting amount is largely degraded in comparison with the leftward or rightward correcting amount. As a result, the extended and contracted amounts of both jacks must be complicatedly controlled in order to make the upward or downward correcting amount equal to the leftward or rightward correcting amount. Referring to Fig. 3, a fluid circuit for working fluid such as operating oil for operating the jacks 38, 40 and 42 comprises a tank 66 storing the working fluid, a pump 68 communicating to the tank, a motor 70 for rotating the pump and directional control valves or change-over valves 72, 74 and 76 disposed for the jacks 38, 40 and 42. Each of the change-over valves 72 and 76 is a P-port block type three-positions and four-ports solenoid operated change-over valve, while the change-over valve 74 operated simultaneously with either one of the change-over valves 72 and 76 is an open center type three-positions and four-ports solenoid operated change-over valve. Each change-over valve has one port communicating to a working fluid outlet of the pump 68 through a common pipe 78, another port communicating to the tank 66 through a common pipe 80, another port communicating to an extension-side liquid chamber of the corresponding jack through a pipe 82 and the other port communicating to a contraction-side liquid chamber of the corresponding jack through a pipe 84. The pipe 78 communicates to the tank 66 through a pipe 86 and a relief valve 88. Check valves 90 and 92 are respectively disposed in the pipes 82 and 84. Each of the check valves 90 and 92 is a pilot check valve which permits the working fluid to enter the corresponding liquid chamber, while blocking the working fluid from flowing out of the corresponding liquid chamber through the corresponding pipe. Also, each check valve permits the working fluid to flow out of the corresponding liquid chamber through the corresponding pipe when pressure is applied to the other pipe. When the head portion 14 is directed upward relative to the tail portion 16, each of the change-over valves 74 and 76 is operated to interconnect the corresponding pipes 78 and 84. When the head portion 14 is directed downward relative to the tail portion 16, each of the change-over valves 74 and 76 is operated to interconnect the corresponding pipes 78 and 82. When the head portion 14 is directed leftward relative to the tail portion 16, each of the change-over valves 72 and 74 is operated to interconnect the corresponding pipes 78 and 84. When the head portion 14 is directed rightward relative to the tail portion 16, each of the change-over valves 72 and 74 is operated to interconnect the corresponding pipes 78 and 82. When the jacks 38 and 40 (or 40 and 42) are extended or contracted, the pipes 82 and 84 connected to the liquid chambers of the other jack 42 (or 38) are respectively closed by the corresponding check valves 90 and 92. By this, the other jack 42 (or 38) are neither extended nor contracted, so that the other jack 42 (or 38) is served as means for interconnecting the head portion and the tail portion similarly to the connecting rod. According to the fluid circuit shown in Fig. 3, the change-over valve 74 corresponding to the jack 40 disposed opposite to the rod 36 is an open center type three-positions and four-ports change-over valve, while each of the change-over valves 72 and 76 corresponding to the other jacks 38 and 42 is a p-port block type change-over valve, so that the pump 68 is always operated without hindering the normal operation of each jack and without using an unloading valve. Referring to Fig. 4, a control circuit for the change-over valves 72, 74 and 76 includes two sets of change-over switches 100 and 102. The change-over switches 100 and 102 respectively have six normal open type switch portions 104, 106, 108, 110, 112 and 113 and those 116, 118, 120, 122, 124 and 126. The switch portions of each change-over switch are divided into two groups, each of which consists of three switch portions. Each of the change-over switches 100 and 102 is manually changed over from a neutral position, where any switch portions are opened, into a first position, where the respective switch portions in one group are closed, and into a second position, where the respective switch portions of the other group are closed. Each switchd portion of the change-over switch 100 is made to correspond to one coil of the change-over valve 72, 74 or 76 together with one switch portion of the change-over switch 102 and connected in series to power supply paths 128 and 130 together with the corresponding coil. An intermediate point between the switch portions 106 and 118 and an intermediate point between the switch portions 112 and 124 are short-circuited. When both change-over switches 100 and 102 are in their neutral positions, any switch portions-are not closed, so that the change-over valves 72, 74 and 76 are not operated. When the change-over switches 100 and 102 are changed over into their first positions, the switch portions 104, 106 and 108 and the switch portions 116, 118 and 120 are closed. Thus, the change-over valves 72 and 74 operatively pull the jacks 38 and 40, so that the head portion is displaced leftward relative to the tail portion. When the change-over switches 100 and 102 are changed over into their second positions, the switch portions 110, 112 and 114 and the switch portions 122, 124 and 126 are closed. Thus, the change-over valves 72 and 74 operatively push the jacks 38 and 40, so that the head portion is displaced rightward relative to the tail portion. When the change-over switch 100 is changed over into the first position and the change-over switch 102 is changed over into the second position, the switch portions 104, 106 and 108 and the switch portions 122, 124 and 126 are closed. Thus, the change-over valves 74 and 76 operatively push the jacks 40 and 42, so that the head portion is displaced downward relative to the tail portion. When the change-over switch 100 is changed over into the second position and the change-over switch 102 is changed over into the first position, the switch portions 110, 112 and 114 and the switch portions 116, 118 and 120 are closed. Thus, the change-over valves 74 and 76 operatively pull the jacks 40 and 42, so that the head portion is displaced obliquely upward relative to the tail portion. Accordingly to the control circuit shown in Fig. 4, the direction of the head portion relative to the tail portion is corrected by changing over two switches 100 and 102 into the first or second position, so that the correcting operation is facilitated.

Claims: A direction correcting device for a shield tunnelling machine having a shield body (12) provided with a head portion (14) and a tail portion (16) following the head portion, comprising: three jacks (38,40,42) respectively having first (58,60) and second (62,64) connecting portions relatively displaced in the axial direction of said tail portion; and wherein each of said jacks being connected at said first connecting portion to said head portion, while being connected at said second connecting portion to said tail portion, characterised in that the device comprises in addition a rod (36) for interconnecting said head portion (14) and said tail (16) portion so as to permit said head portion and said tail portion to swing, while preventing said head portion and said tail portion from relatively displacing in the axial direction of said tail portion; said rod and said jacks being disposed around the axis of said tail portion at angular intervals; whereby the direction of said head portion relative to said tail portion is corrected. A direction correcting device for a shield tunnelling machine according to claim 1, wherein said jacks (38,40,42) and said rod (36) are disposed on an imaginary circle around the axis of said tail portion (16) at equally angular intervals. A direction correcting device for a shield tunnelling machine according to claim 1, wherein said rod (36) having third (44,46) and fourth (48,50) connecting portions incapable of the relative displacement in the axial direction of said tail portion (16), said rod being connected at said third connecting portion to said head portion (14), while being connected at said fourth other connecting portion to sad tail portion (16). A direction correcting device for a shield tunnelling machine according to claim 1, wherein each of said jacks (38,40,42) is a double-acting hydraulic jack having two liquid chambers defined by a piston (54) sliding within a cylinder (52). A direction correcting device for a shield tunnelling machine according to claim 4, wherein it further comprises a pump (68) for supplying pressurized fluid to said jacks (38,40,42) in order to operate said jacks, a solenoid operated change-over valve (72,74,76) corresponded to each of said jacks and disposed between said corresponding jack and said pump to change over flow paths (82,84) for said pressurized fluid, each of said flow paths being individually connected to said liquid chamber, a control circuit (100 ∿ 130) for controlling current applied to said change-over valves (72,74,76), and a check valve (90,92) disposed in each of said flow paths (82,84) permitting said pressurized fluid to be supplied to the corresponding liquid chamber, while preventing said pressurized fluid from flowing out of said corresponding liquid chamber, said check valve also permitting said pressurized fluid to flow out of said corresponding liquid chamber when pressure acts on the other flow path paired with said corresponding flow path. A direction correcting device for a shield tunnelling machine according to claim 5, wherein each of the change-over valves (72,76) corresponding to the jacks (38,42) adjacent to said connecting body (36) is a P-port block type valve, and the change-over valve (74) corresponding to the remaining jack (40) is an open center type three-positions and four-ports valve.

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