Scraper looseness detection system for improving tunneling safety of shield tunneling machine

Abstract

The utility model discloses a scraper looseness detection system for improving the tunneling safety of a shield tunneling machine, which comprises a tool apron, a force transducer and a scraper, and is characterized in that the tool apron is provided with eight tool apron bolt holes; the tool apron is further provided with at least one sensor mounting hole. The force measuring sensor is mounted in a sensor mounting hole of the tool apron; the force measuring sensor comprises a sensor body, an inductive head and a control line. The inductive head of the force measuring sensor protrudes out of the side face, connected with the scraper, of the scraper holder. The scraper comprises a scraper bolt hole, and the scraper is fixed on the tool apron through a bolt. The loosening condition of the scraper in the using process is monitored through the force measuring sensor installed on the scraper holder, an alarm is given according to the pressure grade when the loosening condition reaches the lowest pressure grade, the system transmits prompt information to a touch screen of a shield operation room through PLC operation, shield operation personnel are informed in time, the operation personnel take corresponding measures, and the operation efficiency is improved. A series of unnecessary losses caused by loosening or falling of the cutter are reduced, the construction progress is accelerated, and the construction benefits are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of shield construction equipment, and in particular relates to a scraper loosening detection system for improving the tunneling safety of a shield machine. Background Art

[0002] The shield machine is a crucial piece of equipment used for tunneling, and the scraper on the cutterhead plays a crucial role in the cutting and excavation process. The scraper is used not only to cut soft soil, but also to cut soil and non-hard rock in composite strata after being crushed by the cutterhead. Therefore, the working condition of the scraper has a direct impact on the shield machine's excavation efficiency and construction quality.

[0003] During construction, the shield machine's scraper blade may become loose or fall off, causing the cutterhead's cutting path to deviate, resulting in an excavation diameter that doesn't meet requirements. This increases the workload on other cutting tools and further accelerates tool wear. If this situation isn't discovered and addressed promptly, it can not only reduce construction efficiency but also lead to significant economic losses.

[0004] To address these issues, various technical solutions have been proposed, including methods for monitoring tool wear based on soil color and systems for online, real-time scraper wear monitoring. However, these solutions primarily focus on tool wear monitoring and fail to effectively address the issues of tool loosening and falling. Furthermore, existing scraper installation methods (such as bolted and plug-in installation) are prone to loosening over time, hindering operational performance. Summary of the Invention

[0005] The purpose of the present invention is to provide a scraper loosening detection system for improving the tunneling safety of a shield machine.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A scraper loosening detection system for improving the safety of shield machine excavation, comprising: a blade holder, a force sensor and a scraper, the blade holder being provided with eight blade holder bolt holes; a groove for partially embedding the scraper on one side of the blade holder for mounting the scraper; the blade holder being further provided with at least one sensor mounting hole; the force sensor being mounted in the sensor mounting hole of the blade holder; the force sensor comprising a sensor body, a sensing head and a control line, the sensing head being mounted on the sensor body, the control line being used to transmit the signal generated by the sensing head; the sensing head of the force sensor protruding from the side where the blade holder is connected to the scraper; the scraper comprising a scraper bolt hole, the scraper being fixed to the blade holder by bolts so that the scraper contacts the force sensor.

[0007] The scraper loosening detection system for improving the safety of shield machine excavation as described above of the present invention further has two sensor mounting holes, which are respectively arranged at a first position where the blade holder is closer to the cutting surface and a second position where the blade holder is farther from the cutting surface, and the number of force sensors is two.

[0008] The scraper loosening detection system for improving the shield machine excavation safety of the present invention as described above further has the rated range of the load cell being 5MPa to 10MPa and the stable working temperature range being -10°C to 70°C.

[0009] The scraper loosening detection system for improving the safety of shield machine excavation as described above in the present invention further includes a transfer PCL integrated box, an integrated box power supply circuit, a main control box and a display. The transfer PCL integrated box is connected to the control line of the force sensor through a pre-buried line, the transfer PCL integrated box is connected to the integrated box power supply circuit, the transfer PCL integrated box and the main control box communicate wirelessly, and the main control box and the display are connected through a display connection line.

[0010] The scraper loosening detection system for improving the safety of shield machine excavation as described above in the present invention further comprises the following steps: the embedded line is embedded in the cutterhead spoke beam of the shield machine; a through hole is provided on the cutterhead flange surface and the rotation center of the shield machine, the embedded line enters the central rotating body from the through hole and is connected to the transfer PCL integrated box arranged in the central rotating body.

[0011] The scraper loosening detection system for improving shield machine tunneling safety as described above of the present invention further has the following advantages: the force sensor is fixed in the sensor mounting hole by a shockproof material.

[0012] The scraper loosening detection system for improving the shield machine excavation safety as described above of the present invention further has the display configured with a touch screen interface, which is used to monitor the scraper status in real time, and to adjust display parameters or set alarm thresholds.

[0013] The scraper loosening detection system for improving the safety of shield machine excavation as described above of the present invention further has a data cache module provided in the transfer PCL integrated box. The data cache module temporarily stores data when wireless communication is interrupted, and automatically transmits the data to the main control box after communication is restored.

[0014] The beneficial effects of the present invention are:

[0015] The scraper loosening detection system, designed to enhance shield machine tunneling safety, monitors the high-frequency vibrations generated by the scraper blade as it cuts soil and soft rock during rotation. This system determines whether the scraper is properly cutting the soil and whether the cutterhead has become loose or detached during the cutting process. Two load cells mounted on the scraper head monitor the tightness of the connection between the scraper and the head. If the scraper locking pressure falls below a first set threshold (e.g., 89.09 bar), the scraper is considered loose. If the static locking pressure falls below a second set threshold (e.g., 60 bar), the scraper is considered loose and requires re-tightening. If the pressure remains stable during dynamic movement, it indicates severe scraper wear or breakage. This information allows operators to assess the scraper's operating condition and make timely adjustments and measures to prevent severe scraper wear or detachment, which could lead to insufficient excavation diameter or cutterhead wear, resulting in delays and unnecessary financial losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or other advantages of the present invention will become more clear and easier to understand through the detailed description made in conjunction with the following drawings, which are only exemplary and do not limit the present invention, wherein:

[0017] Figure 1 A schematic diagram of a tool holder according to an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of a force sensor according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the installation combination of a scraper and a blade holder according to an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of a scraper in working state according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of a scraper loosening detection system for improving shield machine tunneling safety according to an embodiment of the present invention.

[0022] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0023] 1. Tool holder, 11. Tool holder bolt hole, 2. Force sensor, 21. Sensor body, 22. Sensing head, 23. Control line, 3. Scraper, 31. Scraper bolt hole, 32. Alloy head, 4. Soft rock, 41. Cutting surface, 5. Embedded line, 6. Transfer PCL integrated box, 7. Integrated box power supply line, 8. Main control box, 9. Display, 91. Display connecting line. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of a scraper loosening detection system for improving tunneling safety of a shield machine according to the present invention will be described with reference to the accompanying drawings.

[0025] The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention. They are illustrative and exemplary and should not be construed as limiting the embodiments and scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the claims and the disclosure of the specification, including technical solutions that adopt any obvious substitutions and modifications to the embodiments described herein.

[0026] The drawings in this specification are schematic diagrams that assist in illustrating the concepts of the present invention and schematically illustrate the shapes of the various components and their interrelationships. Please note that to clearly illustrate the structures of the various components of the embodiments of the present invention, the drawings are not drawn to the same scale. The same reference numerals are used to indicate the same parts.

[0027] Shield machine tools are selected based on the geological conditions and the tool's movement, placement, and shape. Based on the cutting principle, shield machine tools are generally divided into two types: cutting cutters and roller cutters. Other types of tools are generally auxiliary tools. Cutting cutters are further divided into scrapers, toothed cutters, pre-cut cutters, and fishtail cutters. Here is a brief explanation of scraper types. Scraper installation methods are divided into bolt-on, insert-on, and welded types. Currently, bolt-on and insert-on scrapers are commonly used in shield machines, with welded types gradually being phased out. Although welded scrapers are more secure, they are not conducive to quickly replacing worn or damaged scrapers. Bolted and insert-on scrapers are easy to disassemble, but over long-term use, they are prone to loose bolts and pin ends. Loose scrapers accelerate wear or damage. To monitor scraper use, check for loose bolts and pin ends, and ensure the scraper is securely connected to the blade holder.

[0028] refer to Figures 1 to 5 A scraper loosening detection system for improving the tunneling safety of a shield machine according to an embodiment of the present invention is described. The system mainly includes a blade holder 1 , a force sensor 2 and a scraper 3 .

[0029] The blade holder 1 is provided with blade holder bolt holes 11 for mounting the scraper 3, and at least one sensor mounting hole for mounting the force sensor 2. A groove is provided on the side of the blade holder 1 where the scraper 3 is mounted, into which the scraper 3 partially fits. The groove prevents the scraper from swinging, thereby improving the position stability of the scraper during excavation.

[0030] The toolholder is lathe-machined to create the mounting area for the load cell. The load cell wiring is routed through pre-buried holes within the toolholder. According to the cutterhead design drawings, the 8-hole scraper toolholder uses M24*70mm hexagon socket bolts with a strength grade of 10.9 and a tightening torque of 890Nm. The torque unit can be converted to kilograms-force-meters (kgf / m) using the formula: 1Nm = 0.102kgf / m, resulting in 890Nm = 90.82kgf / m. The conversion between kilograms-force-per-square-centimeter (kgf / cm2) and bar can be expressed mathematically as follows: 1kgf / m = 0.981bar, 90.82kgf / m * 0.981bar = 89.09bar. From the above formula, we can know that after locking the scraper, the sensor pressure display value is ≥89.09bar, which means that the scraper has been tightened in place. Subsequently, the scraper looseness can be judged by the scraper holder force sensor display value displayed on the touch screen in the operating room. Based on this information, the excavation data and tool changing work can be adjusted in time.

[0031] The force sensor 2 is fixed to the blade holder 1 through this mounting hole. It comprises a sensor body 21, a sensing head 22, and a control line 23. The sensing head 22 contacts the surface of the blade holder 1 through the sensor body 21 and protrudes from the side of the blade holder 1 where it connects to the scraper 3. This head is used to detect the tightening state of the scraper 3 during operation. The force sensor is designed based on the principle that elastic elements are subjected to force. The force changes its resistance value through deformation, which is then converted into an electrical signal by the force measuring circuit for output, thereby achieving force measurement. The load cell has an 8.5mm diameter and 5mm height. Its rated capacity (RC) is 5-10MPa, its full-scale output (RO) is 0.5-1.2mV / V, its maximum excitation voltage is 12V, its nonlinearity is ±1.0%RO, its hysteresis is ±1.0%RO, its creep (30 minutes) is ±0.5%RO, its zero-point output is ±2% ofRO, its impedance is 350Ω±5%, its temperature compensation range is 0-50°C, its operating stability range is -10°C to 70°C, its insulation resistance is 5000MΩ, its input impedance is 700±10Ω, its output impedance is 700±5%, its lead cable dimensions are φ1.6*4Core*3m, its safe overload is 120%RC, and its material is stainless steel. Due to the harsh conditions in the cutterhead construction environment, conventional sensors are difficult to install and use. However, due to its compact size, high accuracy, and excellent stability, this load cell is ideal for use in the cutterhead scraper anti-loosening function.

[0032] The scraper 3 is bolted to the blade holder 1. Bolt holes 31 of the scraper 3 are aligned with bolt holes 11 of the blade holder 1, ensuring contact between the scraper 3 and the force sensor 2. The force sensor 2 can sense pressure changes between the scraper 3 and the blade holder 1 in real time and transmit the signal to a remote device for analysis via control line 23. Weld the scraper holder with the force sensor to the designated position on the cutter disc, then install the scraper. Tighten and lock it with M24 hexagon socket bolts with a strength grade of 10.9 or higher. The tightening condition is determined by the pressure feedback from the force sensor. The scraper can be used only after the tightening force of all scrapers reaches 89.09 bar or higher.

[0033] In practice, the system of the present invention provides two sensor mounting holes, one located near the cutting surface 41 of the blade holder 1, and the other located farther from the cutting surface 41. A force sensor 2 is installed at each location to monitor the force applied to the scraper 3 at different positions. Each force sensor 2 has a rated range of 5 MPa to 10 MPa and can maintain stable operation within an operating temperature range of -10°C to 70°C, ensuring that the system can accurately detect the tightening status of the scraper 3 under various operating conditions.

[0034] To enable remote monitoring and data transmission, the present invention also includes a transfer PCL integrated box 6, integrated box power supply circuit 7, a master control box 8, and a display 9. The force sensor 2 is connected to the transfer PCL integrated box 6 via pre-buried circuit 5, which is in turn connected to the integrated box power supply circuit 7. Wireless communication is used to transmit data between the integrated box 6 and the master control box 8. The display 9 is connected to the master control box 8 via a display cable 91 and displays the force status of the scraper 3 in real time.

[0035] In the shield machine's cutterhead structure, pre-buried wiring 5 is routed along the cutterhead spokes and enters the central rotor through holes in the cutterhead flange, ultimately connecting to the intermediate PCL integrated box 6. This wiring method effectively prevents cable entanglement and damage during cutterhead rotation, ensuring long-term stable system operation. The intermediate PCL integrated box transmits signals wirelessly to the main control box, reducing wiring pressure on the central rotor. Wireless transmission is also less susceptible to external electromagnetic interference, resulting in low overall cost and stable performance, eliminating wiring and cable maintenance costs.

[0036] In order to improve the stability of the force sensor 2, the sensor 2 is fixed in the sensor mounting hole of the tool holder 1 by means of shockproof material to prevent the high frequency vibration during the operation of the shield machine from affecting the measurement accuracy.

[0037] The display 9 is equipped with a touch screen interface, and the operator can monitor the working status of the scraper 3 in real time through the touch screen, and can adjust the display parameters or set the alarm threshold as needed, so as to detect abnormal situations in time and take corresponding measures to ensure construction safety.

[0038] In addition, a data cache module is provided in the transfer PCL integrated box 6 of the present invention. When wireless communication is interrupted, the data cache module can temporarily store the data collected by the force sensor 2. After the communication is restored, the system will automatically transmit the stored data to the main control box 8 to ensure the integrity of the data.

[0039] Combine Figure 5 The scraper blade loosening detection system, designed to improve shield machine tunneling safety, operates as follows: The scraper generates high-frequency vibrations as it rotates forward and reverse through the cutterhead, cutting and draining soft rock or soil. Prolonged high-frequency vibrations can cause loosening of the bolts and lead to metal fatigue. Therefore, two sets of load cells are installed on the scraper base to monitor the tightening of the scraper bolts. The initial tightening pressure of the load cells is ≥89.09 bar, respectively monitoring the nearest and farthest points of the scraper blade's alloy tip. Normally, loosening or detachment of the scraper blade during operation begins at the cutting end, i.e., the scraper blade's alloy tip. At this point, the load cells promptly display the loosening pressure at the scraper blade tip. Once the loosening pressure reaches 60 bar, the display system indicates an abnormal pressure reading for that load cell. If the loosening value of the load cell continues to decrease, causing the pressure of the other load cell to fall below 60 bar, the system will issue a warning to the operator via the touchscreen. The operator can then take appropriate measures and make adjustments based on the warning message and the corresponding cutterhead scraper number.

[0040] The technical features disclosed above are not limited to the disclosed combinations with other features. Those skilled in the art may also make other combinations between the technical features according to the purpose of the invention to achieve the purpose of the invention.

Claims

1. A scraper loosening detection system for improving shield machine excavation safety, characterized in that: include: A knife seat (1), a force sensor (2) and a scraper (3), wherein the knife seat (1) is provided with eight knife seat bolt holes (11); a groove for partially embedding the scraper (3) is provided on one side of the knife seat (1) for mounting the scraper (3); the knife seat (1) is also provided with at least one sensor mounting hole; the force sensor (2) is mounted in the sensor mounting hole of the knife seat (1); the force sensor (2) comprises a sensor body (21), a sensing head (22) and a control line (23); the sensing head (22) is mounted on the sensor body (21), and the control line (23) is used to transmit the signal generated by the sensing head (22); the sensing head (22) of the force sensor (2) protrudes from the side of the knife seat (1) where the scraper (3) is connected; the scraper (3) comprises a scraper bolt hole (31), and the scraper (3) is fixed to the knife seat (1) by bolts so that the scraper (3) contacts the force sensor (2).

2. The scraper loosening detection system for improving shield machine excavation safety according to claim 1 is characterized in that: The number of the sensor mounting holes is two, and the sensor mounting holes are respectively arranged at a first position where the tool holder (1) is closer to the cutting surface (41) and a second position where the tool holder (1) is farther from the cutting surface (41). The number of the force sensors (2) is two.

3. The scraper loosening detection system for improving shield machine excavation safety according to claim 1 is characterized in that: The force sensor (2) has a rated range of 5MPa to 10MPa and a stable operating temperature range of -10°C to 70°C.

4. The scraper loosening detection system for improving shield machine excavation safety according to claim 1 is characterized in that: The invention also includes a transfer PCL integrated box (6), an integrated box power supply circuit (7), a main control box (8) and a display (9), wherein the transfer PCL integrated box (6) is connected to the control line (23) of the force sensor (2) via a pre-buried circuit (5), the transfer PCL integrated box (6) is connected to the integrated box power supply circuit (7), the transfer PCL integrated box (6) communicates with the main control box (8) via wireless communication, and the main control box (8) is connected to the display (9) via a display connection line (91).

5. The scraper loosening detection system for improving shield machine excavation safety according to claim 4 is characterized in that: The pre-buried line (5) is pre-buried in the cutterhead spoke beam of the shield machine; a through hole is provided on the cutterhead flange surface and the rotation center of the shield machine, and the pre-buried line (5) enters the central rotating body from the through hole and is connected to the transfer PCL integrated box (6) provided in the central rotating body.

6. The scraper loosening detection system for improving shield machine excavation safety according to claim 1 is characterized in that: The force sensor (2) is fixed in the sensor installation hole via a shockproof material.

7. The scraper loosening detection system for improving shield machine excavation safety according to claim 4 is characterized in that: The display (9) is equipped with a touch screen interface, through which the status of the scraper (3) is monitored in real time, and display parameters can be adjusted or alarm thresholds can be set.

8. The scraper loosening detection system for improving shield machine excavation safety according to claim 1 is characterized in that: A data cache module is provided in the transfer PCL integrated box (6). The data cache module temporarily stores data when wireless communication is interrupted, and automatically transmits the data to the main control box (8) after communication is restored.

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