A full-face tunnel boring machine with a retractable cutterhead and a separation ring.

Abstract

This invention discloses a full-face tunnel boring machine with a retractable cutterhead and a separation ring, comprising: a shell with a retraction space inside, and a central shaft mounted at the center, the central shaft being rotatable and movable along its own axis; a cutterhead connected to the central shaft, the outer periphery of which is smaller than the retraction space so that it can retract into the retraction space with the central shaft; and a central ring fitted around the outer periphery of the cutterhead and rotating synchronously with the cutterhead, retracting with the cutterhead until the central ring abuts against the end face of the shell and separates from the cutterhead. This invention simplifies the retraction operation and reduces manual intervention through the synchronous rotation and automatic separation mechanism of the central ring and the cutterhead, thereby improving construction efficiency. Furthermore, it eliminates the need for personnel to enter the tunnel to disassemble the cutterhead, reducing construction risks.

Description

Technical Field

[0001] This invention relates to the field of cutterhead tunnel boring machine technology, and in particular, to a full-face tunnel boring machine with a retractable cutterhead and a separation ring. Background Technology

[0002] The construction process of a full-face tunnel boring machine (TBM) typically includes three stages: equipment launch, normal tunneling, and TBM reception. Before the equipment reaches its designated location, a receiving shaft is usually prepared in advance to facilitate its reception. With the continuous expansion of urban pipeline construction, especially in densely populated urban core areas, the space for receiving shafts is often limited, making traditional TBM reception methods difficult to implement.

[0003] In the design of full-face tunnel boring machines (TBMs), to ensure continuous and efficient tunneling, the cutterhead's excavation diameter is typically slightly larger than the shield's diameter. This design means that when the main machine needs to retract, the shield will obstruct the cutterhead's retraction. The traditional solution is to manually disassemble the cutterhead partially to reduce its diameter and allow for smooth retraction. However, this method is complex and inefficient. Especially when the tunnel diameter is small, it is difficult for personnel to enter the tunnel for disassembly work, further increasing construction difficulty and risk. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a full-face tunnel boring machine with a retractable cutterhead and a separation ring.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A full-face tunnel boring machine with a retractable cutterhead and a separation ring includes: an outer shell with a retraction space inside and a central shaft mounted at the center, the central shaft being able to rotate and move along its own axis; a cutterhead connected to the central shaft, the outer periphery of which is smaller than the retraction space so that it can retract into the retraction space with the central shaft; and a central ring fitted around the outer periphery of the cutterhead and rotating synchronously with the cutterhead, retracting with the cutterhead until the central ring abuts against the end face of the outer shell and then separates from the cutterhead.

[0007] Furthermore, a diameter-maintaining cutter is installed on the end face of the central ring facing away from the outer shell.

[0008] Furthermore, the outer periphery of the cutter head is provided with a first wedge-tightening conical surface, and the inner periphery of the central ring is provided with a second wedge-tightening conical surface that is the same as the first wedge-tightening conical surface. The second wedge-tightening conical surface narrows towards the end facing away from the outer shell.

[0009] Furthermore, the inner peripheral wall of the central ring is provided with protrusions, and the cutter head is provided with a slot for the protrusions to be inserted.

[0010] Furthermore, a force transmission part is connected to the end of the central shaft, and the force transmission part is connected and fixed to the cutter head through a connecting part.

[0011] Furthermore, a slag discharge channel is provided at the bottom of the retraction space.

[0012] Furthermore, a receiving opening is provided on the periphery of the central ring, and a supporting block is hinged in the receiving opening. The supporting block has a contracted state and an open state. In the contracted state, the supporting block is contracted within the receiving opening. In the open state, the supporting block partially protrudes from the outer peripheral wall of the central ring of the cutter head. When the cutter head separates from the central ring and generates relative movement, the cutter head can drive the supporting block to move from the contracted state to the open state. When the cutter head is completely separated from the central ring, the supporting block has reached the open state.

[0013] Furthermore, the support block includes a central circular block, with multiple driven teeth arranged around the peripheral wall of the central circular block. A transmission gear is rotatably mounted at the bottom of the receiving port, with the bottom of the transmission gear protruding from the receiving port. A row of active teeth is provided on the outer periphery of the cutter head. The bottom of the transmission gear meshes with the active teeth, and the top meshes with the driven teeth, so as to drive the support block to rotate when the cutter head approaches or separates from the central ring.

[0014] Furthermore, when the support block is in the extended state, one driven tooth at one end of the support block is located in the tooth groove of the transmission gear; when the support block is in the retracted state, one driven tooth at the other end of the support block is located in the tooth groove of the transmission gear; the receiving opening is provided with a mounting block and a limiting block to restrict the support block from swinging between the mounting block and the limiting block; the support block in the retracted state and the extended state are respectively close to the mounting block and the limiting block, and the support block in the retracted state has a gap with the mounting block; the support block in the retracted state can move toward the mounting block to the avoidance state, and all driven teeth on the support block in the avoidance state are completely disengaged from the tooth groove of the transmission gear to avoid the rotation coverage range of the transmission gear; a reset post is elastically mounted on the mounting block, and the reset post is used to push the support block in the avoidance state back to the retracted state.

[0015] Furthermore, the mounting block is provided with a movable hole, and the reset column is elastically and movably mounted in the movable hole. One end of the reset column facing the support block is provided with a column head, and the other end passes through the movable hole and is connected to a nut. A compression spring is sleeved in the middle of the reset column, with one end of the compression spring abutting against the column head and the other end abutting against the mounting block.

[0016] The present invention has the following beneficial effects:

[0017] By designing a cutterhead that retracts into the retractable space along with the central axis, this invention allows the tunneling machine to retract without disassembling the cutterhead, significantly reducing the need for receiving shaft space and enabling the equipment to operate smoothly in space-constrained environments such as urban core areas. Traditional tunneling machines often require manual partial disassembly of the cutterhead when retraction is needed, a process that is not only complex but also time-consuming and labor-intensive. This invention simplifies the retraction operation through a synchronous rotation and automatic separation mechanism between the central ring and the cutterhead, reducing manual intervention and thus improving construction efficiency. Furthermore, it eliminates the need for personnel to enter the tunnel to disassemble the cutterhead, reducing construction risks.

[0018] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 This is an internal sectional view of the present invention;

[0021] Figure 2 This is a schematic diagram of the front structure of the cutter head and the central ring;

[0022] Figure 3 This is a schematic diagram of the disassembled structure of the cutter head and the central ring;

[0023] Figure 4 This is a schematic diagram of the back structure of the cutter head and the central ring;

[0024] Figure 5 yes Figure 4 Sectional view at point AA;

[0025] Figure 6 yes Figure 5 Enlarged view of point B;

[0026] Figure 7 This is a cross-sectional view of the support block in the avoidance state;

[0027] Figure 8 yes Figure 7 Enlarged view at point C;

[0028] Figure 9 This is a cross-sectional view of the tension block in its extended state;

[0029] Figure 10This is a schematic diagram of the disassembled structure of the cutter head, the support block, and the transmission gear.

[0030] Legend:

[0031] 100 outer shell, 110 retraction space, 111 force transmission part, 112 connecting part, 120 central shaft, 130 slag discharge channel;

[0032] Cutter head 200, first wedge conical surface 210, insert 220, active tooth 230, main cutter 240;

[0033] Center ring 300, diameter-maintaining cutter 310, second wedge-tightening cone surface 320, protrusion 330, receiving port 340, transmission gear 350, tooth groove 351, mounting block 360, movable hole 361, reset post 370, post head 371, nut 372, compression spring 373, limit block 380;

[0034] Support block 400, center circular block 410, driven tooth 411. Detailed Implementation

[0035] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0038] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0039] Please refer to Figure 1 and Figure 2 A preferred embodiment of the present invention provides a full-face tunnel boring machine with a retractable cutterhead and a separation ring, comprising a housing 100, a cutterhead 200, and a central ring 300.

[0040] The housing 100 has a retraction space 110 inside, and a central shaft 120 is installed at the center of the housing 100. The central shaft 120 can rotate and move along its own axis. The rear end of the central shaft 120 is usually connected to a mobile platform so that it can be driven by the mobile platform to move along its own axis, thereby extending and retracting back and forth. A rotary drive mechanism is also provided on the mobile platform to drive the central shaft 120 to rotate. The rotary drive mechanism can be a motor or a rotary cylinder.

[0041] The cutter head 200 is connected to the central shaft 120. The outer periphery of the cutter head 200 is smaller than the retraction space 110 so that it can retract into the retraction space 110 along with the central shaft 120.

[0042] The central ring 300 is sleeved on the outer periphery of the cutter head 200 and can rotate synchronously with the cutter head 200. The central ring 300 can retract with the cutter head 200 until the central ring 300 abuts against the end face of the outer shell 100 and then separates from the cutter head 200. Initially, the central ring 300 can retract with the cutter head 200. However, after the central ring 300 abuts against the end face of the outer shell 100, the central ring 300 is interfered with by the outer shell 100 and can no longer retract with the cutter head 200, thus achieving separation from the cutter head 200.

[0043] This invention provides a full-face tunnel boring machine (TBM) with a retractable cutterhead and a separation ring, allowing the TBM to retract without disassembling the cutterhead. This significantly reduces the space required for the receiving shaft, enabling the equipment to operate smoothly in space-constrained environments such as urban core areas. Traditional TBMs often require manual partial disassembly of the cutterhead 200 when retraction is needed, a process that is not only complex but also time-consuming and labor-intensive. This invention simplifies the retraction operation through the synchronous rotation and automatic separation mechanism of the central ring 300 and the cutterhead 200, reducing manual intervention and thus improving construction efficiency. Furthermore, it eliminates the need for personnel to enter the tunnel to disassemble the cutterhead, reducing construction risks. By reducing the need for manual disassembly and reassembly of the cutterhead, this invention helps reduce maintenance costs and equipment downtime, further improving the economic efficiency of construction. This allows the TBM to adapt to more geological and environmental conditions, especially in urban underground pipeline construction, enabling it to flexibly address various construction challenges.

[0044] Reference Figure 2 In some embodiments of the present invention, a diameter-maintaining cutter 310 is installed on the end face of the central ring 300 facing away from the outer shell 100, thereby ensuring the excavation radius and avoiding the absence of a cutter at the central ring 300, which would affect the excavation effect.

[0045] Reference Figure 1 In some embodiments of the present invention, the cutterhead 200 has a first wedge-tightening conical surface 210 on its outer periphery, and the central ring 300 has a second wedge-tightening conical surface 320 on its inner periphery that interacts with the first wedge-tightening conical surface 210. The second wedge-tightening conical surface 320 narrows towards the end facing away from the outer shell 100, so that during rotary excavation, the central ring 300 is subjected to a reaction force and fits more tightly against the cutterhead 200, and a tight fit is achieved by the cooperation of the first wedge-tightening conical surface 210 and the second wedge-tightening conical surface 320. It is understood that the cutterhead 200 also has a main cutter 240 on its excavation end face.

[0046] Reference Figure 2 and Figure 3 In some embodiments of the present invention, the inner peripheral wall of the central ring 300 is provided with protrusions 330, and the cutter head 200 is provided with recesses 220 for the protrusions 330 to be inserted. By inserting the protrusions 330 into the recesses 220, torque transmission is achieved, thereby enabling the cutter head 200 to drive the central ring 300 to rotate synchronously. It is understood that multiple sets of protrusions 330 and recesses 220 can be arranged around the perimeter to achieve force transmission at multiple positions and avoid excessive stress concentration that could damage the protrusions 330.

[0047] Reference Figure 1 In some embodiments of the present invention, a force transmission part 111 is connected to the end of the central shaft 120. The force transmission part 111 can be connected to the central shaft 120 via a key to achieve torque transmission. The force transmission part 111 is sleeved on the central shaft 120, which is typically a stepped shaft. The axial positioning and fixation of the force transmission part 111 can be achieved by using the shoulder of the stepped shaft in conjunction with a limiting nut. The force transmission part 111 is connected and fixed to the cutter head 200 via a connecting part 112. The connecting part 112 can be a connecting rod, and multiple rods are arranged in a circular pattern at intervals to achieve multi-position connection and connection stability.

[0048] Reference Figure 1 In some embodiments of the present invention, a slag discharge channel 130 is provided at the bottom of the retraction space 110, and a pump can be connected to the rear end of the slag discharge channel 130 to realize slag discharge pumping and discharge the mud formed by excavation.

[0049] Reference Figure 3 and Figure 4In some embodiments of the present invention, a receiving opening 340 is provided around the central ring 300, and a supporting block 400 is hinged within the receiving opening 340. The supporting block 400 and the inner wall of the receiving opening 340 are provided with corresponding holes for hinged connection via a hinge shaft (not shown in the figure). The supporting block 400 has a retracted state and an extended state. In the retracted state, the supporting block 400 is retracted within the receiving opening 340. When the cutter head 200 separates from the central ring 300 and generates relative movement, the cutter head 200 can drive the supporting block 400 to move from the retracted state to the extended state. When the cutter head 200 is completely separated from the central ring 300, the supporting block 400 has reached the extended state. Figure 6 As shown, the extended clamping block 400 protrudes from the outer peripheral wall of the central ring 300 of the cutterhead 200, thereby pressing against the inner wall of the tunnel. This ensures that the central ring 300 can be tightly connected to the inner wall of the tunnel after separation from the cutterhead 200, reducing the possibility of swaying, tilting, or even overturning after separation. Figure 5 As shown, the tensioning block 400 in the retracted state retracts into the receiving opening 340, which does not affect the normal operation of the cutterhead 200 during rotation and excavation.

[0050] Understandably, in order to achieve circumferential tightening of the tunnel inner wall, multiple sets of support blocks 400 and receiving openings 340 are arranged around the tunnel inner wall, thereby tightening the tunnel inner wall at multiple circumferential positions, so that the position of the central ring 300 is stable after the support blocks 400 are opened.

[0051] Reference Figure 5 and Figure 10 In a further embodiment of the present invention, the support block 400 includes a central circular block 410, with a plurality of driven teeth 411 arranged around its peripheral wall. The center of the central circular block 410 is provided with a hinge hole for hinged into the receiving opening 340. A transmission gear 350 is rotatably mounted on the bottom of the receiving opening 340. A row of driving teeth 230 is provided on the outer periphery of the cutter head 200. The bottom of the transmission gear 350 meshes with the driving teeth 230, and the bottom of the transmission gear 350 protrudes from the receiving opening 340 to facilitate meshing with the driving teeth 230. The top of the transmission gear 350 meshes with the driven teeth 411 so as to drive the support block 400 to rotate when the cutter head 200 approaches or separates from the central ring 300.

[0052] Reference Figure 5 and Figure 9In some embodiments of the present invention, when the support block 400 is in the open state, one driven tooth 411 at one end of the support block 400 is in the tooth groove of the transmission gear 350; when the support block 400 is in the retracted state, one driven tooth 411 at the other end of the support block 400 is in the tooth groove of the transmission gear 350; that is, regardless of whether the row of driven teeth 411 on the support block 400 is in the retracted or open state, at least one driven tooth 411 is in the tooth groove 351 of the transmission gear 350, so that the support block 400 can be rotated by the rotation of the transmission gear 350, thereby avoiding the driven tooth 411 in the retracted and open states from disengaging from the transmission gear 350, which would prevent the state from being switched. The receiving port 340 is provided with a mounting block 360 and a limiting block 380 to restrict the swinging of the tensioning block 400 between the mounting block 360 and the limiting block 380. The tensioning block 400 in its retracted state and its extended state are respectively close to the mounting block 360 and the limiting block 380. In the retracted state, the tensioning block 400 has a gap with the mounting block 360, allowing it space to move towards the mounting block 360. In the extended state, the tensioning block 400 is in contact with the limiting block 380, thus ensuring that when the tensioning block 400 is in the extended state, it does not continue to move away from the retracted state. The space is designed to prevent the support block 400 from disengaging from the open state, which would cause the last remaining driven tooth 411 to disengage from the tooth groove 351 of the transmission gear 350. In the retracted state, the support block 400 can move towards the mounting block 360 to a avoidance state. In this avoidance state, all driven teeth 411 on the support block 400 completely disengage from the tooth groove 351 of the transmission gear 350, thus avoiding the rotational coverage area of ​​the transmission gear 350. That is, when the transmission gear 350 drives the support block 400 to the retracted state, the transmission gear 350 moves all driven teeth 411 to one side of the top of the transmission gear 350. In normal operation, after the cutter head 200 is completely separated from the central ring 300, the support block 400 remains in the open state. When the cutter head 200 approaches the central ring 300, the driving tooth 230 on the cutter head 200 drives the transmission gear 350 to rotate clockwise, and the transmission gear 350 drives the driven teeth 411 to rotate counterclockwise until... Figure 5 In the indicated state, the cutter head 200 and the central ring 300 are fully closed; however, because the support block 400 in the open state has space to move towards the retracted state and is not limited by the active protrusion 230 on the cutter head 200, the support block 400 may move a certain range towards the retracted state. At this time, when the cutter head 200 approaches the central ring 300, before the cutter head 200 and the central ring 300 are fully closed, the support block 400 has already reached the retracted state. When the cutter head 200 and the central ring 300 continue to move until they are fully closed, it will cause the support block 400 to move to the avoidance state, achieving the desired effect. Figure 7 and Figure 8In the state shown, even if the rotation of the transmission gear 350 cannot drive the driven cam 411 and the support block 400 to rotate, the support block 400 in the avoidance state has a gap or fit with the mounting block 360, thus preventing the support block 400 in the open state from being unstable and causing excessive and uncontrolled movement of the support block 400 when the cutter head 200 and the central ring 300 close. However, if the support block 400 is in the avoidance state for a long time, since all the driven cams 411 are completely disengaged from the tooth grooves 351 of the transmission gear 350, when the cutter head 200 separates from the central ring 300, it will not drive the driven cam 411 to rotate. The tension block 400 moves towards the open state. For this purpose, a reset pin 370 is elastically mounted on the mounting block 360. The reset pin 370 pushes the tension block 400 from the avoidance state back to the retracted state, making the movement of the retracted tension block 400 towards the avoidance state an elastic movement. The reset pin 370 always applies an elastic force, ensuring that at least one driven tooth 411 is in the tooth groove 351. When the cutter head 200 separates from the central ring 300, the rotation of the transmission gear 350 drives the tension block 400 towards the open state, thus making the state switching effective. When the cutter head 200 and the central ring 300 are completely close together, the support block 400 will be in one of two states—a retracted state or an avoidance state—or somewhere in between. This allows the support block 400 to move to an open state or near an open state after the cutter head 200 and the central ring 300 are completely separated. Furthermore, because the driving tooth 230 and the transmission gear 350 are still meshed in the retracted state, and the transmission gear 350 is restricted by the driving tooth 230, the positions of the transmission gear 350 and the support block 400 remain stable and will not deviate. When the cutter head 200 separates from the central ring 300, the initial state of the support block 400 is stable, preventing it from floating arbitrarily. When the support block 400 moves to the open state and abuts against the limit block 380, the active convex tooth 230 and the transmission gear 350 have completely separated and there is no transmission engagement. This avoids the situation where the active convex tooth 230 and the transmission gear 350 are not completely separated when the support block 400 moves to the open state and abuts against the limit block 380, which would prevent the cutter head 200 from continuing to separate from the central ring 300 and thus jamming.

[0053] Reference Figure 6 In a specific embodiment of the present invention, the mounting block 360 is provided with a movable hole 361, and the reset post 370 is elastically and movably mounted in the movable hole 361. One end of the reset post 370 facing the support block 400 is provided with a post head 371, and the other end passes through the movable hole 361 and is connected to a nut 372 to prevent the reset post 370 from disengaging from the movable hole 361. A compression spring 373 is sleeved in the middle of the reset post 370. One end of the compression spring 373 abuts against the post head 371, and the other end abuts against the mounting block 360, thereby providing an elastic force for the reset post 370.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A full-face tunnel boring machine with a retractable cutterhead and a separation ring, characterized in that, include: The outer casing (100) has a retractable space (110) inside and a central shaft (120) is mounted in the center, the central shaft (120) being able to rotate and move along its own axis; The cutter head (200) is connected to the central shaft (120), and its outer periphery is smaller than the retraction space (110) so that it can retract into the retraction space (110) along with the central shaft (120). The central ring (300) is sleeved on the outer periphery of the cutter head (200) and can rotate synchronously with the cutter head (200). It can move backward with the cutter head (200) until the central ring (300) abuts against the end face of the outer shell (100) and then separates from the cutter head (200). The cutter head (200) has a first wedge-tightening cone surface (210) on its outer periphery, and the center ring (300) has a second wedge-tightening cone surface (320) on its inner periphery that is the same as the first wedge-tightening cone surface (210). The second wedge-tightening cone surface (320) narrows towards the end facing away from the outer shell (100). The central ring (300) is provided with a receiving port (340) on its periphery. A support block (400) is hinged in the receiving port (340). The support block (400) has a contracted state and an open state. In the contracted state, the support block (400) is contracted in the receiving port (340). In the open state, the support block (400) partially protrudes from the outer peripheral wall of the central ring (300). When the cutter disc (200) separates from the central ring (300) and generates relative movement, the cutter disc (200) can drive the support block (400) to move from the contracted state to the open state. When the cutter disc (200) and the central ring (300) are completely separated, the support block (400) has reached the open state. The support block (400) includes a central circular block (410), and a plurality of driven teeth (411) are arranged around the periphery of the central circular block (410). A transmission gear (350) is rotatably mounted on the bottom of the receiving port (340), and the bottom of the transmission gear (350) protrudes from the receiving port (340). A row of active teeth (230) is provided on the outer periphery of the cutter disc (200). The bottom of the transmission gear (350) meshes with the active teeth (230), and the top meshes with the driven teeth (411), so as to drive the support block (400) to rotate when the cutter disc (200) approaches or separates from the central ring (300).

2. The full-face tunnel boring machine with a retractable cutterhead and separation ring according to claim 1, characterized in that, The end face of the central ring (300) facing away from the outer shell (100) is equipped with a diameter-maintaining cutter (310).

3. The full-face tunnel boring machine with a retractable cutterhead and separation ring according to claim 1, characterized in that, The inner peripheral wall of the central ring (300) is provided with a protrusion (330), and the cutter head (200) is provided with a slot (220) for the protrusion (330) to be inserted.

4. The full-face tunnel boring machine with a retractable cutterhead and separation ring according to claim 1, characterized in that, The end of the central shaft (120) is connected to a force transmission part (111), and the force transmission part (111) is connected and fixed to the cutter head (200) through a connecting part (112).

5. The full-face tunnel boring machine with a retractable cutterhead and separation ring according to claim 1, characterized in that, The bottom of the retraction space (110) is provided with a slag discharge channel (130).

6. The full-face tunnel boring machine with a retractable cutterhead and separation ring according to claim 1, characterized in that, When the support block (400) is in the extended state, one driven tooth (411) at one end of the support block (400) is located in the tooth groove of the transmission gear (350); when the support block (400) is in the retracted state, one driven tooth (411) at the other end of the support block (400) is located in the tooth groove of the transmission gear (350); the receiving port (340) is provided with a mounting block (360) and a limiting block (380) to restrict the support block (400) from swinging between the mounting block (360) and the limiting block (380); the support block (400) in the retracted and extended states. The tension block (400) in its retracted state has a gap with the mounting block (360) and the limiting block (380), respectively. The tension block (400) in its retracted state can move toward the mounting block (360) to a avoidance state. All driven teeth (411) on the tension block (400) in the avoidance state are completely disengaged from the tooth grooves of the transmission gear (350) to avoid the rotation coverage of the transmission gear (350). A reset post (370) is elastically and movably mounted on the mounting block (360). The reset post (370) is used to push the tension block (400) in the avoidance state back to the retracted state.

7. The full-face tunnel boring machine with a retractable cutterhead and separation ring according to claim 6, characterized in that, The mounting block (360) is provided with a movable hole (361), and the reset column (370) is elastically and movably installed in the movable hole (361). The reset column (370) has a column head (371) at one end facing the support block (400), and the other end passes through the movable hole (361) and is connected to a nut (372). A compression spring (373) is sleeved in the middle of the reset column (370). One end of the compression spring (373) abuts against the column head (371), and the other end abuts against the mounting block (360).

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