An integrated transport and safety machine for lining transportation and installation

Abstract

The present invention provides an integrated transport and safety machine for transporting and installing linings, comprising a vehicle frame, an arch mounting mechanism and a side mounting mechanism mounted on the vehicle frame, with two sets of side mounting mechanisms symmetrically arranged on either side of the arch mounting mechanism; a lifting cylinder, a first transverse displacement cylinder, and a first longitudinal displacement cylinder of the arch mounting mechanism are mounted between the vehicle frame, a lifting beam, a supporting beam, and the arch lining, allowing the arch lining to be adjusted and positioned to the arch installation position on three planes; a telescopic arm, a first rotary cylinder, and a second rotary cylinder of the side mounting mechanism are connected between the vehicle frame, the through beam, and the lining support, with the lining support connected to the side lining, allowing the side lining to be adjusted and installed via the telescopic arm, with the side lining positioned laterally and below the arch lining. The integrated transport and safety machine can transport and install pre-assembled linings, requires fewer construction workers, has high installation efficiency, high installation precision, and is economical and practical.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel lining installation, and in particular to an integrated transportation and safety machine for lining transportation and installation. Background Art

[0002] Over the past two decades, my country's transportation infrastructure has experienced unprecedented development. Mountain tunnels, in particular, have undergone advancements from traditional to modern support structures, and from monolithic linings to composite linings. Mountain tunnel construction methods have also evolved from traditional mining methods to the New Austrian Tunneling Method (NATM) and tunnel boring machine (TBM) construction methods. Currently, the NATM composite lining is widely used worldwide. However, the NATM construction process involves multiple steps, complex organization, a long construction period, harsh working environments, and limited assurance of quality. However, it offers excellent geological adaptability and unique advantages in cost-effectiveness and flexibility. The TBM method offers simple procedures, rapid construction, and excellent safety. However, it is generally only used for long, circular tunnels constructed primarily in hard rock and is unsuitable for short tunnels or underground projects with complex geological conditions. To adapt to diverse geological conditions, accelerate construction, and improve project quality, improvements to currently popular construction methods and lining structures are necessary to achieve optimal economic and technical benefits.

[0003] From the perspective of excavation methods, the drill-and-blast excavation method used by the New Austrian Tunneling Method (NATM) is highly adaptable and applicable to a wide range of geological conditions. It can excavate a variety of cross-section shapes while meeting tunnel construction limits, demonstrating its strong adaptability. The TBM method, on the other hand, has stringent requirements for geological conditions, cross-section shape, and tunnel length, which limits its scope of application and reduces its adaptability, making it less advantageous than the NATM. Furthermore, from the perspective of lining structure, the composite lining structure employed by the NATM fully embodies its design and construction philosophy of fully leveraging the self-bearing capacity of the surrounding rock. However, its slow construction speed and complex construction steps have prevented it from meeting the requirements of modern tunnel construction for mechanization, efficiency, safety, and environmental protection. Furthermore, the secondary lining cannot immediately bear loads after pouring. The prefabricated lining employed by the TBM method offers rapid construction, reliable quality, and immediate load-bearing capability, significantly improving the tunnel construction environment. Furthermore, the various joints in the prefabricated lining increase its flexibility, which, to some extent, also reflects the principles of the NATM. At the same time, with the development of mechanized and factory-based tunnel construction, prefabricated linings are increasingly being used in various tunnel and underground projects. Therefore, it is necessary to conduct research on prefabricated tunnel linings in conjunction with the New Austrian Tunneling Method (NATM) construction philosophy to address the current challenges of speed, quality, and efficiency in engineering construction.

[0004] The existing tunnel prefabricated lining installation device and construction method still have the following problems: (1) the transportation and installation of prefabricated arch wall lining are separate, the construction efficiency is low and the cost is high;

[0005] (2) When installing the prefabricated arch wall lining, the arch lining and the side lining are installed separately. The arch lining needs to be supported before the side lining is installed, which makes the installation process complicated. Summary of the Invention

[0006] The present invention provides an integrated transport and installation machine for lining transportation and installation, which can transport and install pre-assembled linings, requires fewer construction workers, has high installation efficiency and precision, and is economical and practical.

[0007] The technical solution adopted to achieve the above-mentioned purpose of the present invention is:

[0008] A transport and safety integrated machine for lining transportation and installation comprises at least a vehicle frame, an electrical and hydraulic system mounted on the vehicle frame, a power compartment, and a traveling mechanism connected to the bottom of the vehicle frame. A section of prefabricated arch wall lining comprises an arch lining section and two side lining sections. The vehicle frame is mounted with an arch mounting mechanism and a side mounting mechanism, wherein two sets of side mounting mechanisms are symmetrically arranged on either side of the arch mounting mechanism.

[0009] The arch lining is installed on the arch installation mechanism, and the arch installation mechanism includes a supporting crossbeam, a lifting crossbeam, a lifting cylinder, a first transverse oil cylinder and a first longitudinal oil cylinder, wherein two lifting crossbeams are provided, and the lifting cylinders are vertically connected between the lifting crossbeam and the vehicle frame so that the lifting crossbeams are transversely installed at the front and rear ends of the vehicle frame; the supporting crossbeam is longitudinally installed on the lifting crossbeam, and the first transverse oil cylinder is installed between the lifting crossbeam and the supporting crossbeam so that the supporting crossbeam moves transversely along the lifting crossbeam; the arch lining is installed on the supporting crossbeam, and the first longitudinal oil cylinder is installed between the arch lining and the supporting crossbeam so that the arch lining moves longitudinally along the supporting crossbeam, so that the arch lining is adjusted and positioned to the arch installation position on three planes;

[0010] The side lining is installed on the side mounting mechanism, and the side mounting mechanism includes a telescopic arm, a through beam, a lining support, a first rotating oil cylinder and a second rotating oil cylinder, wherein both ends of the telescopic arm are connected to the through beam and the vehicle frame, and the three are all hingedly connected, the first rotating oil cylinder is located at the hinge between the telescopic arm and the through beam, and the first rotating oil cylinder is hingedly connected to the telescopic arm and the through beam, the second rotating oil cylinder is located at the hinge between the telescopic arm and the vehicle frame, and the second rotating oil is hingedly connected to the telescopic arm and the vehicle frame, the first rotating oil cylinder and the second rotating oil cylinder are telescopically extended and retracted, thereby adjusting the orientation of the telescopic arm; the shapes of the through beam and the lining support are both arc structures matching the shape of the side lining, the lining support is installed on the through beam and connected to the side lining, so that the side lining is installed on the side mounting mechanism, and the side lining is located on the side and lower side of the arch lining. When the side lining is installed, the telescopic arm, the first rotating oil cylinder and the second rotating oil cylinder are extended and retracted to adjust the side lining to the side mounting position.

[0011] The bottom of the frame is also symmetrically installed with more than four sets of whole-machine adjustment mechanisms, which include a support bracket, lifting legs, a sliding beam, a transverse movement assembly and a longitudinal movement assembly, wherein the lifting legs are installed at the four corners of the bottom of the support bracket, and the sliding beam is installed on the support bracket and the frame through the transverse movement assembly and the longitudinal movement assembly.

[0012] The transverse movement assembly includes a third transverse movement cylinder and a transverse movement slide. The transverse movement slide is fixedly mounted on the upper portion of the support bracket. A transverse movement slot is provided at the bottom of the sliding beam. The transverse movement slot and the transverse movement slide are slidably connected to the sliding beam so that the sliding beam is slidably connected to the support bracket. The third transverse movement cylinder is mounted between the support bracket and the sliding beam.

[0013] The longitudinal movement assembly includes a third longitudinal movement cylinder and a longitudinal movement slide. The longitudinal movement slide is fixedly installed at the bottom of the frame. A longitudinal movement slide is provided on the upper part of the sliding beam. The longitudinal movement slide and the longitudinal movement slide are slidingly connected, so that the sliding beam frame is slidingly connected to the sliding beam. The third longitudinal movement cylinder is installed between the frame and the sliding beam.

[0014] Both ends of the lifting beam are provided with mounting holes, and guide columns are connected to the mounting holes through ball joints. The bottom of the guide columns is fixedly connected to the frame. When the lifting cylinder lifts the lifting beam, the guide columns limit the lifting beam.

[0015] The lifting beam is provided with a first guide hole, and the bottoms of both ends of the supporting beam are connected to first sliding tenons, which are respectively connected to the first guide holes of the two lifting beams. The transverse dimension of the first guide hole is larger than the transverse dimension of the first sliding tenon, and the first transverse movement cylinder drives the first sliding tenon to move transversely along the first guide hole;

[0016] The supporting crossbeam is a box beam structure that is wide at the top and narrow at the bottom. A second guide hole is provided in the middle of the supporting crossbeam. A second sliding tenon is installed corresponding to the bottom of the arch lining. The second sliding tenon is installed in the second guide hole. The longitudinal dimension of the second guide hole is larger than the longitudinal dimension of the second sliding tenon. The first longitudinal movement cylinder drives the second sliding tenon to move longitudinally along the second guide hole.

[0017] Temporary support rods are distributed and connected between the arch lining and the side lining and the vehicle frame.

[0018] There are more than two lining supports, each of which is provided with a slide groove at the bottom. The lining supports are mounted on the through beam by straddling the slide groove, and the lining supports are slidably connected to the through beam. A second longitudinal movement oil cylinder is distributed and connected between the through beam and the lining supports. The second longitudinal movement oil cylinder is extended and retracted to make the lining supports move longitudinally along the through beam.

[0019] The side lining is installed with a threaded rod and a positioning shaft, the lining support is provided with a threaded hole and a positioning hole, the positioning shaft is installed in the positioning hole, and the threaded rod is connected to the threaded hole, so that the side lining is installed on the side installation mechanism.

[0020] There are more than two telescopic arms distributed between the same side mounting mechanism and the vehicle frame, and the number and position of the first rotary cylinder and the second rotary cylinder correspond to the telescopic arms.

[0021] The frame is a combined beam structure, including wheel beams, column beams, connecting beams and main cross beams, wherein there are two wheel beams, two connecting beams and two main cross beams, and four column beams. Two wheel beams are arranged in parallel at the bottom, the column beams are connected to the two ends of each wheel beam, the connecting beam is connected to the column beam and is perpendicular to the wheel beam, the main cross beam is connected in parallel between the two connecting beams and the main cross beams are all located above and inside the wheel beams; the side mounting mechanism is installed on the upper surface of the wheel beam, and the arch mounting mechanism is installed on the upper part of the main cross beam and the connecting beam.

[0022] The walking mechanism is a tire-type structure, including a suspension assembly, a wheel group, a steering system and a braking system. The suspension assembly is provided with 10 axis groups and 20 groups, including 3 active suspension axes, 4 driven braking suspension axes and 3 driven non-braking suspension axes. The wheel group includes a driving wheel group, a braking wheel group and a driven wheel group.

[0023] A driver's cab is provided at both the front and rear ends of the frame.

[0024] Compared with the existing technology, the integrated transportation and safety machine provided by the present invention has the following advantages: 1. The integrated transportation and safety machine provided by the present invention can transport a section of prefabricated arch wall lining (including a section of arch lining and two sections of side lining) from the narrow space of the tunnel to the installation position at one time, and can accurately adjust the posture and install the large-sized and heavy arch lining and side lining to meet the lining installation accuracy requirements.

[0025] 2. The arch installation mechanism and the two sets of side installation mechanisms in the present invention can work independently and simultaneously without interfering with each other. The installation of a section of prefabricated arch wall lining of a tunnel can be completed at one time without the need to support the lining, and the installation efficiency is high.

[0026] 3. The arch installation mechanism of the present invention utilizes hydraulic cylinders (the lifting cylinder, the first transverse displacement cylinder, and the first longitudinal displacement cylinder) to connect all movable components. During transportation, the hydraulic circuits containing these cylinders maintain neutral pressure, effectively supporting the movable components. Furthermore, the movable components of the arch installation mechanism are supported by first sliding tenons and guide columns, ensuring a stable and reliable structure. The arch lining is installed using second sliding tenons, providing positioning and preventing lateral shearing, ensuring stable and reliable transport of the arch lining.

[0027] 4. The side mounting mechanism of the present invention is connected with the positioning shaft on the side lining to play the role of positioning and anti-shearing. In addition, the movable parts are connected by cylinders (the internal cylinder of the telescopic arm, the first rotating cylinder, the second rotating cylinder, and the second longitudinal movement cylinder). During transportation, the hydraulic circuit where the cylinder is located is in a neutral pressure-maintaining state, so that the cylinder can effectively support the movable parts, and the side lining is stable and reliable during transportation.

[0028] 5. During transportation, the integrated transport and safety machine provided in the present invention further reinforces the arch lining and the side lining to the vehicle frame through temporary support rods to prevent the lining sheets of the arch lining and the side lining from being displaced due to swaying and vibration during transportation.

[0029] 6. The adjustment directions of the whole machine adjustment mechanism, arch installation mechanism and side installation mechanism of the integrated transportation and security machine provided by the present invention are all adjustable in multiple directions (longitudinal, transverse and vertical directions), and the installation freedom is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of the integrated transport and safety machine for lining transportation and installation provided by the present invention;

[0031] Figure 2 This is a schematic diagram of the transport arch lining and side lining of the integrated transport and safety machine of the present invention;

[0032] Figure 3 It is a structural schematic diagram of the frame of the present invention;

[0033] Figure 4 Schematic diagram of the local structure of the walking mechanism in the present invention Figure 1 ;

[0034] Figure 5 Schematic diagram of the local structure of the walking mechanism in the present invention Figure 2 ;

[0035] Figure 6 It is a structural diagram of the whole machine adjustment mechanism in the present invention;

[0036] Figure 7 This is a schematic diagram of the connection between the whole machine adjustment mechanism and the frame in the present invention;

[0037] Figure 8 It is a structural schematic diagram of the sliding beam of the whole machine adjustment mechanism in the present invention;

[0038] Figure 9 It is a structural schematic diagram of the arch installation mechanism in the present invention;

[0039] Figure 10 Schematic diagram of the installation of the arch mounting mechanism and the vehicle frame of the present invention;

[0040] Figure 11 Schematic diagram of the installation of the arch installation mechanism and the arch lining in the present invention Figure 1 ;

[0041] Figure 12 Schematic diagram of the installation of the arch installation mechanism and the arch lining in the present invention Figure 2 ;

[0042] Figure 13 It is a schematic structural diagram of the supporting beam of the arch mounting mechanism of the present invention;

[0043] Figure 14 Schematic diagram of the installation of the side mounting mechanism and the vehicle frame in the present invention;

[0044] Figure 15 It is a structural schematic diagram of the side mounting mechanism in the present invention;

[0045] Figure 16 It is a schematic structural diagram of the side lining in the present invention;

[0046] Figure 17 It is a schematic diagram of the side lining installed on the side mounting mechanism in the present invention;

[0047] Figure 18 This is a rear view of the integrated transport and safety machine of the present invention when transporting in a lined tunnel section;

[0048] Figure 19 This is a rear view of the integrated transport and safety machine in the present invention at the lining installation position;

[0049] Figure 20 This is a schematic diagram of the integrated transportation and security machine of the present invention being supported on the whole machine adjustment mechanism;

[0050] Figure 21 This is a front view of the arch lining installed on the integrated transport and security machine of the present invention;

[0051] Figure 22 This is a front view of the side lining of the integrated transportation and security machine of the present invention;

[0052] Figure 23 This is a schematic diagram of the integrated transportation and security machine of the present invention after installation;

[0053] Figure 24 This is a schematic diagram of the integrated transport and security machine of the present invention being retracted to its original state after installation;

[0054] In the figure: 100-arch lining, 200-side lining, 2001-threaded rod, 2002-positioning shaft, 2003-connector, 2004-reinforcement seat, 300-lined tunnel section;

[0055] 1- frame, 11- wheel beam, 12- column beam, 13- connection beam, 14- main beam;

[0056] 2-travel mechanism, 21-suspension assembly, 22-steering system, 23-wheel assembly;

[0057] 3-machine adjustment mechanism, 31-support bracket, 32-lifting legs, 33-sliding beam, 34-third transverse oil cylinder, 35-transverse slide plate, 36-third longitudinal oil cylinder, 37-longitudinal slide plate, 38-transverse slide chute, 39-longitudinal slide chute;

[0058] 4 - arch mounting mechanism, 41 - lifting beam, 411 - first guide hole, 412 - mounting hole, 42 - supporting beam, 421 - first sliding tenon, 422 - second guide hole, 43 - lifting cylinder, 44 - first transverse cylinder, 45 - first longitudinal cylinder, 46 - guide column, 47 - second sliding tenon;

[0059] 51-telescopic arm, 52-through beam, 53-lining support, 531-slideway, 532-threaded hole, 533-positioning hole, 54-second longitudinal movement cylinder, 55-first rotary cylinder, 56-second rotary cylinder;

[0060] 6-temporary support rod, 7-power compartment, 8-electrical and hydraulic system, 9-driver's cab. DETAILED DESCRIPTION

[0061] The present invention will be described in detail below with reference to the accompanying drawings.

[0062] The installation of a precast tunnel arch wall lining in the present invention is divided into the installation of a single arch lining 100 and two side linings 200. In this embodiment, both the arch lining and the side lining are assembled from six lining pieces. Specifically, the side lining and the arch lining are joined using bolts and connectors.

[0063] The overall structure of the transport and installation integrated machine for lining transportation provided in this embodiment is as follows: Figure 1 and Figure 2 As shown, it includes a frame 1, a traveling mechanism 2, a whole machine adjustment mechanism 3, an arch mounting mechanism 4 and a side mounting mechanism 5, wherein the traveling mechanism and the whole machine adjustment mechanism are installed at the bottom of the frame, and are respectively used for the traveling and preliminary centering of the whole machine; the arch mounting mechanism and the side mounting mechanism are both installed on the frame, wherein two sets of side mounting mechanisms are symmetrically arranged on both sides of the arch mounting mechanism, and are respectively used for the installation of the arch lining and the side lining on both sides.

[0064] In this embodiment, the frame is a composite beam structure, which is welded from Q355 plates. Figure 3 As shown, it includes wheel beams 11, column beams 12, connecting beams 13, and main crossbeams 14. There are two wheel beams, connecting beams, and main crossbeams each, and four column beams. Two wheel beams are arranged parallel to the bottom, and column beams are connected to each wheel beam at both ends, supporting the upper structure, equipment, and assembled arch lining and side lining of the entire machine. The connecting beams are connected to the column beams and are perpendicular to the wheel beams. The main crossbeams are connected in parallel between the two connecting beams and are located above and inside the wheel beams. The main crossbeams and connecting beams support the arch adjustment mechanism and arch lining. The frame is the load-bearing component of the integrated transportation and safety machine and serves as the carrier of various mechanisms. The cross-sections of the frame beams are all box-shaped.

[0065] The traveling mechanism is installed at the bottom of the frame, that is, the lower surface of the wheel beam. Figure 3 Specifically, the running mechanism is a tire-type structure, including a suspension assembly 21, a wheel set 23, a steering system 22 and a braking system (not shown in the figure), such as Figure 4 and Figure 5 As shown. The suspension assembly features 10 axles and 20 groups, including three active suspension axles, four driven brake suspension axles, and three driven non-braking suspension axles. The active suspension primarily consists of a slewing bearing, a suspension frame, a drive axle, a drive motor and reducer, tires, and wheel rims. The driven suspension primarily consists of a slewing bearing, a suspension frame, a driven axle, tires, wheel rims, and wheel hubs. During transportation, the entire suspension is grouped using a three-point support system. Each group is equipped with a hydraulic balancing system to ensure even loading during transport and installation on uneven surfaces.

[0066] The wheel assembly includes a driving wheel assembly, a braking wheel assembly, and a driven wheel assembly. The driving wheel assembly consists of a drive axle, a reducer, a motor, a wheel, and a rim. The braking wheel assembly consists of a braking axle, a rim, and a wheel. The driven wheel assembly consists of a driven axle, a rim, and a wheel. In this embodiment, the wheel rims are widened to reduce tire wear. A tire pressure monitoring device is also included to provide real-time monitoring of tire usage. The steering system adopts an independent steering mode and consists of a slewing bearing, a steering cylinder, a steering angle encoder, and other components. The braking system comprises service brakes, parking brakes, and emergency brakes. Service brakes are primarily achieved by controlling the drive hydraulic system, with hydraulic drum brakes acting in conjunction. The parking brake consists of a normally closed disc brake and a hydraulic drum brake. The emergency brake is achieved by a combination of a normally closed disc brake and a hydraulic drum brake. The suspension assembly, wheel assembly, steering system, and braking system of the running mechanism are conventional, and their detailed structures are not described in this embodiment.

[0067] The traveling mechanism can realize the oblique movement, semi-figure-eight steering and figure-eight steering modes of the transportation and safety integrated machine, thereby moving the transportation and safety integrated machine from the pre-assembly site outside the tunnel to the lining installation position inside the tunnel. In addition, the traveling mechanism has a certain positioning accuracy, so that the lateral error between the whole machine and the center line of the arch segment is less than 200mm, and the longitudinal error is less than 500mm, which facilitates the subsequent adjustment mechanism of the whole machine to preliminarily position and align the longitudinal and transverse center lines of the transportation and safety integrated machine with the tunnel lining installation position.

[0068] The whole machine adjustment mechanism is also installed on the lower surface of the wheel beam. In this embodiment, four sets of whole machine adjustment mechanisms are symmetrically installed at the bottom of the frame. Figure 3 The whole machine adjustment mechanism includes a support bracket 31, a lifting leg 32, a sliding beam 33, a transverse component and a longitudinal component, wherein the transverse component includes a third transverse oil cylinder 34 and a transverse slide 35, and the longitudinal component includes a third longitudinal oil cylinder 36 and a longitudinal slide 37. Figures 6 to 8 As shown in the figure, the support bracket is the primary load-bearing component of the machine's adjustment mechanism and is assembled from Q355 steel plates. The lifting legs are mounted at the four corners of the support bracket, utilizing a mechanical lifting mechanism. The lifting screws of the lifting legs utilize T-threads for load bearing and transmission, adjusting the vertical movement of the machine. The sliding beam, assembled from Q355 steel plates, is mounted on the support bracket and frame via transverse and longitudinal assemblies and is used to adjust the machine's transverse and longitudinal movement.

[0069] Specifically, the transverse sliding plate is fixedly installed on the upper part of the support bracket, and a transverse sliding groove 38 is provided at the bottom of the sliding beam. Figure 8The transverse slideway and the transverse slide are connected in a sliding manner. The cylinder body of the third transverse oil cylinder is fixed on the support bracket through a support. The piston rod of the third transverse oil cylinder is connected to the sliding beam through a hinge seat, so that the sliding beam and the frame connected to the sliding beam slide horizontally along the support bracket. The longitudinal slide is fixedly installed at the bottom of the frame. Figure 7 A longitudinal slide 39 is provided on the upper portion of the sliding beam, which is slidably connected to the longitudinal slide. The cylinder body of the third longitudinal cylinder is fixed to the lower surface of the wheel beam, and the piston rod of the third longitudinal cylinder is connected to the sliding beam via a hinge, allowing the vehicle frame to slide longitudinally along the sliding beam. Both the transverse and longitudinal slides are made of engineering plastic alloy. Each set of the complete vehicle adjustment mechanism is equipped with two third transverse and longitudinal cylinders. The complete vehicle adjustment mechanism enables vertical, longitudinal, and lateral movement of the entire vehicle, thereby facilitating the initial alignment of the transport and safety vehicle with the tunnel lining installation site.

[0070] The arch mounting mechanism is installed on the upper part of the main beam and the connecting beam, such as Figures 9 to 12 As shown, the arch mounting mechanism includes a lifting beam 41, a supporting beam 42, a lifting unit, a transverse unit, and a longitudinal unit, wherein the lifting unit, the transverse unit, and the longitudinal unit are respectively a lifting cylinder 43, a first transverse cylinder 44, and a first longitudinal cylinder 45. There are two lifting beams, and the lifting cylinders are vertically connected between the lifting beams and the frame, so that the lifting beams are horizontally mounted on the front and rear ends of the frame (on the two connecting beams). Specifically, the cylinder body of the lifting cylinder is fixed to the frame (on the column beam), see Figure 10 The piston rod of the lifting cylinder is connected to the lifting beam. There are 8 lifting cylinders, distributed on both sides of the end of each lifting beam, to ensure that they can support the weight of the entire arch installation mechanism and the arch lining, while driving them up and down. Both ends of the lifting beam are provided with mounting holes 412, and the mounting holes are connected to guide columns 46 via ball joints. The bottom of the guide columns is fixedly connected to the frame. When the lifting cylinder lifts the lifting beam, the guide columns can serve as a limit support. Figure 21 .

[0071] The support beam is longitudinally mounted on the lifting beam, and a first transverse cylinder is installed between the lifting beam and the support beam, enabling the support beam to move laterally along the lifting beam. Specifically, the lifting beam is provided with a first guide hole 411, and a first sliding tenon 421 is connected to the bottom of each end of the support beam. The first sliding tenon is respectively connected to the first guide hole of the two lifting beams, enabling the support beam to be longitudinally mounted on the lifting beam. The transverse dimension of the first guide hole is larger than the transverse dimension of the first sliding tenon. The first transverse cylinder drives the first sliding tenon to move laterally along the first guide hole, thereby enabling the support beam to move laterally on the lifting beam, thereby driving the arch lining to move laterally. Specifically, the cylinder body of the first transverse cylinder is fixed to the lifting beam, and the piston rod of the first transverse cylinder is connected to the support beam. A total of eight first transverse cylinders are provided, distributed on both sides of the bottom of each end of the support beam. The first sliding tenon is an arc-shaped structure. When the piston rods of the two front groups of first transverse moving cylinders are extended (retracted) at a low speed and the piston rods of the two rear groups of first transverse moving cylinders are retracted (extended) at a low speed, the arch lining and supporting beam can be rotated around the first sliding tenon to achieve vertical angle posture adjustment.

[0072] The arch lining is installed on the supporting beam, and the first longitudinal movement cylinder is installed between the arch lining and the supporting beam to move the arch lining longitudinally along the supporting beam. Specifically, a second guide hole 422 is provided in the middle of the supporting beam, and a second sliding tenon 47 is installed at the bottom of the arch lining. Figure 12 The second sliding tenon is installed in the second guide hole. The longitudinal dimension of the second guide hole is larger than that of the second sliding tenon. The first longitudinal oil cylinder drives the second sliding tenon to move longitudinally along the second guide hole, thereby driving the longitudinal movement of the arch lining. Specifically, two first longitudinal oil cylinders are installed on both sides of the end of the supporting beam close to the tunnel face. The cylinder body of the first longitudinal oil cylinder is fixed to the supporting beam, and the piston rod of the first longitudinal oil cylinder is connected to the arch lining. Figure 11 The supporting beam is a box beam structure that is wide at the top and narrow at the bottom, such as Figure 13 As shown, the upper flange plate is wider and can stably support the arch lining.

[0073] The arch installation mechanism adjusts the arch lining in the vertical, transverse, and longitudinal directions until it is positioned at the arch installation location, aligning it with the already installed arch lining. During transportation, the hydraulic circuits containing the lift cylinder, first lateral cylinder, and first longitudinal cylinder are all in a neutral pressure-maintaining state, allowing the cylinders to effectively support the moving parts.

[0074] The side mounting mechanism is installed on the upper surface of each of the two wheel beams. Figure 14 As shown, the side mounting mechanism includes a telescopic arm 51, a through beam 52, a lining support 53, a second longitudinal movement cylinder 54, a first rotation cylinder 55 and a second rotation cylinder 56. Figure 15As shown, in this embodiment, the telescopic arm, the first rotary cylinder, and the second rotary cylinder are connected to form a multi-degree-of-freedom adjustment structure, which can adjust the through-beam above the telescopic arm and the like with multiple degrees of freedom. Specifically, both ends of the telescopic arm are hingedly connected to the through-beam and the vehicle frame (wheel beam), and the first rotary cylinder is hingedly connected between the telescopic arm and the through-beam. Specifically, the cylinder body of the first rotary cylinder is hingedly connected to the telescopic arm, and the piston rod of the first rotary cylinder is connected to the hinge lug on the through-beam. The second rotary cylinder is hingedly connected between the telescopic arm and the vehicle frame. Specifically, the cylinder body of the second rotary cylinder is hingedly connected to the wheel beam, and the piston rod of the second rotary cylinder is connected to the hinge lug on the telescopic arm. The second rotary cylinder is extended and retracted, so that the telescopic arm supports the side mounting mechanism and the side lining to adjust their positions around the vehicle frame. The first rotary cylinder is extended and retracted, so that the side mounting mechanism and the side lining can also be adjusted together around the telescopic arm. In order to ensure the stability of the support, more than two telescopic arms are distributed between the same side mounting mechanism and the frame. In this embodiment, three are provided, and the number and position of the first rotating oil cylinder and the second rotating oil cylinder correspond to the telescopic arms.

[0075] The shapes of the through beam and the lining support are both arc-shaped structures that match the shape of the side lining. The through beam and the lining support are both welded from steel plates and have good rigidity. There are more than two lining supports, and in this embodiment, there are three. The bottom of the lining support is provided with a slide 531, and the lining support is installed on the through beam by straddling the slide, and the lining support is slidably connected to the through beam. The second longitudinal movement cylinder is distributed and connected between the through beam and the lining support, and the second longitudinal movement cylinder is telescopic to move the lining support longitudinally along the through beam. Specifically, the second longitudinal movement cylinder is arranged on both sides of the two ends of the through beam, the cylinder body of the second longitudinal movement cylinder is fixed on the through beam, and the piston rod of the second longitudinal movement cylinder is connected to the lining support. Each set of side mounting mechanisms has a total of 4 second longitudinal movement cylinders, see Figure 15 .

[0076] The side lining is installed with a threaded rod 2001 and a positioning shaft 2002, and the lining support is provided with a threaded hole 532 and a positioning hole 533. The positioning shaft is installed in the positioning hole, and the threaded rod is connected to the threaded hole, so that the side lining is installed on the side installation mechanism, such as Figure 14 、 Figure 16 and Figure 17 During transportation, the side lining is located below the arch lining, making it easier for the transport and safety vehicle to move to the tunnel lining installation location. Figure 1 When installing the side lining, the telescopic arm is extended and rotated to adjust the side lining to the side installation position, and is aligned with the arch lining and the installed side lining.

[0077] In order to further ensure the stability of the arch lining and the side lining during transportation, in this embodiment, temporary support rods 6 are distributed and connected between the arch lining and the side lining and the frame. Figure 2 After the integrated tunnel security machine is initially aligned with the tunnel lining installation site, the temporary support rods are removed before installing the arch lining and side lining.

[0078] The transport and installation integrated machine for lining transportation provided in this embodiment also includes a power cabin 7, an electrical and hydraulic system 8 and a driver's cab 9 installed on the vehicle frame. Figure 1 .

[0079] The power compartment houses the engine, flexible coupling, transfer case, and variable displacement pump. The transport and safety integrated machine is equipped with two engines, ensuring smooth travel to its destination even if one fails (with unchanged driving capacity, but at half the speed). Each engine drives six variable displacement pumps through the transfer case. These provide hydraulic power to the wheel drive system, steering system, and suspension assembly of the traveling mechanism during transport, and to the arch mounting mechanism and two sets of side mounting mechanisms during lining installation.

[0080] The electro-hydraulic control system includes a hydraulic drive unit, hydraulic steering unit, hydraulic suspension unit, complete hydraulic adjustment unit, arch hydraulic installation unit, and side hydraulic installation unit. During lining transport, the hydraulic drive unit, hydraulic steering unit, and hydraulic suspension unit are activated, while the complete hydraulic adjustment unit, arch hydraulic installation unit, and side hydraulic installation unit are deactivated. When the transport and installation vehicle arrives for initial positioning, only the complete hydraulic adjustment unit is activated, while the other units are deactivated. During lining installation, the complete hydraulic adjustment unit is locked, the arch hydraulic installation unit and side hydraulic installation unit are activated, and the hydraulic drive unit, hydraulic steering unit, and hydraulic suspension unit are deactivated.

[0081] A driver's cab is located at each end of the transport and installation machine, allowing operation from either end. The two cabs are interlocked. The cabs are equipped with a steering wheel, joystick, buttons, switches, and other operating components, as well as various monitoring instruments, displays, and fault alarm systems to meet operational needs. The cabs are thermally and soundproofed, equipped with air conditioning, safety glass, and a front windshield with wipers. The front cab noise level is less than 75 decibels. An electric horn is installed near each cab for driving warnings. Both cabs feature an industrial color display, displaying real-time data on the transport and installation machine's operation and parameter settings. The display is scrolled using function keys on both sides of the display. Each page displays subsystem pressure, solenoid valve current, encoder angle, engine speed, and engine operating data (speed, coolant temperature, and oil pressure).

[0082] The front and rear cabs have essentially the same layout, with the steering wheel, buttons, and switches all arranged ergonomically. The centrally located seat offers excellent legroom and is adjustable fore and aft, as well as the backrest angle. The front cab measures 1.6m (length) x 1.6m (width) x 1.6m (height), while the rear cab measures 1.6m (length) x 2m (width) x 1.6m (height).

[0083] The construction process of the integrated transport and installation machine for lining transportation provided in this embodiment includes the following steps:

[0084] (1) Multiple side lining sheets and arch lining sheets are spliced ​​together to form a whole, thereby obtaining two sections of side lining and one section of arch lining. In this embodiment, the side lining and the arch lining are both spliced ​​together by six lining sheets. Specifically, the side lining and the arch lining are spliced ​​together by bolts and connectors 2003. Specifically, connectors are used to connect adjacent lining sheets at the bolt connection positions. The connectors have sufficient rigidity to avoid stress on the bolts and prevent relative slippage of the six lining sheets during transportation and installation.

[0085] Then install the second sliding tenon on the arch lining to match the arch installation mechanism. Figure 12 , install the threaded rod and positioning shaft on the side lining, which are connected with the side mounting mechanism, see Figure 16 A reinforcement seat 2004 is also installed on the side lining for connecting the temporary support rod to the side lining.

[0086] (2) Lift the side lining and arch lining and install them on the side installation mechanism and arch installation mechanism of the transport and safety machine respectively; wherein the threaded rod and positioning shaft of the side lining are respectively installed in the threaded hole and positioning hole of the lining support, the second sliding tenon of the arch lining is installed in the second guide hole, and both sections of the side lining are installed on the side and lower side of the arch lining, so that the transport and safety machine can move freely in the tunnel where the prefabricated arch wall lining has been installed when transporting the side lining and arch lining. The lifting tool can be a gantry crane, etc. In order to ensure the stability of transportation, the side lining and arch lining are temporarily fixed to the transport and safety machine by temporary support rods, see Figure 2 ;

[0087] At this time, both side linings are installed on the side and lower part of the arch lining to ensure that the transport and safety integrated machine can move in the narrow tunnel. Figure 18 .

[0088] (3) Move the integrated transport and safety machine to the lining installation position in the tunnel, and move the air duct to a position close to the wheel group; in this embodiment, the driver can drive the integrated transport and safety machine into the lining installation position in the tunnel from the driver's cab at the front end of the frame, Figure 18 This is a schematic diagram of the transport safety integrated machine in the lined tunnel section 300. Figure 19 This is a schematic diagram of the transportation and safety integrated machine at the lining installation position.

[0089] (4) Lift the travel mechanism of the transport and safety integrated machine through the suspension assembly so that its wheel set is suspended in the air, and the transport and safety integrated machine is supported on the ground through the whole machine adjustment mechanism, such as Figure 20 shown.

[0090] (5) Operate the lifting legs, the third transverse oil cylinder and the third longitudinal oil cylinder of the whole machine adjustment mechanism to achieve preliminary positioning and alignment of the longitudinal and transverse center lines of the integrated transport and safety machine with the tunnel lining installation position. This step is the preliminary alignment. After the alignment is completed, all temporary support rods are removed;

[0091] To facilitate the alignment steps, prepare the following before installation:

[0092] Mark the longitudinal centerline of the installed side lining and arch lining, mark the longitudinal centerline of the installed arch lining on the ground at the location to be installed, and mark the transverse centerline of the arch lining to be installed on the ground at the location to be installed. Mark the longitudinal and transverse centerlines of the arch lining to be installed, and mark the longitudinal centerline of the side lining to be installed;

[0093] When adjusting the adjustment mechanism of the whole machine, first adjust the telescopic height of the lifting legs so that the installed arch lining is basically parallel to the arch lining on the transportation and safety integrated machine, then adjust the lateral position of the transport and installation vehicle so that the longitudinal center lines of the installed arch lining and the arch lining on the transportation and safety integrated machine are coaxial, and finally adjust the longitudinal position of the transportation and safety integrated machine so that the longitudinal spacing between the arch lining to be installed and the lining of the installed arch is less than 100mm.

[0094] (6) Operate the arch installation mechanism to raise the arch lining to near the installation height, such as Figure 21 As shown, the lifting cylinder of the arch installation mechanism is extended and retracted to lift the lifting beam, so that the arch lining is raised to near the installation height;

[0095] At the same time, operate the telescopic arm of the side installation mechanism to move the side lining to the vicinity of the installation position, such as Figure 22 As shown, the first rotary cylinder and the second rotary cylinder of the side installation mechanism are extended and retracted to adjust the orientation of the telescopic arm. The telescopic arm is extended and retracted to move the side lining to the vicinity of the installation position.

[0096] (7) Operate the arch installation mechanism to fine-tune the arch lining. Fine-tune the positioning can be achieved by extending and retracting the lifting cylinder, the first transverse cylinder, and the first longitudinal cylinder in three planes to align the arch lining with the installed arch lining. At this time, align the arch lining with the completed arch lining as a reference;

[0097] In this embodiment, the arch lining can not only perform longitudinal posture adjustment (Y-axis translation), lateral posture adjustment (X-axis translation) and vertical posture adjustment (Z-axis translation), but also perform longitudinal angular posture adjustment (rotation around the Y axis), lateral angular posture adjustment (rotation around the X axis) and vertical angular posture adjustment (rotation around the Z axis);

[0098] 1) Longitudinal angle posture adjustment (rotation around the Y axis)

[0099] The two groups of lifting cylinders on the left side rise (fall) at a low speed, and the two groups of lifting cylinders on the right side fall (rise) at a low speed, causing the lifting beam, supporting beam and arch lining to deflect around the ball joints on the columns to achieve longitudinal angle posture adjustment.

[0100] 2) Horizontal angle adjustment (rotation around the X axis)

[0101] The two front lifting cylinders rise (fall) at a low speed, and the two rear lifting cylinders fall (rise) at a low speed, causing the lifting beam, supporting beam and arch lining to deflect around the ball joints on the columns to achieve lateral angle posture adjustment.

[0102] 3) Vertical angle adjustment (rotation around the Z axis)

[0103] The piston rods of the two front first transverse cylinders are extended (retracted) at a low speed, and the piston rods of the two rear first transverse cylinders are retracted (extended) at a low speed, causing the arch lining and supporting beam to rotate around the first sliding tenon between the supporting beam and the lifting beam to achieve vertical angle posture adjustment.

[0104] (8) Operate the side installation mechanism to fine-tune the side lining. Fine-tune the positioning can be achieved by telescoping the first rotary cylinder, the second rotary cylinder, the telescopic arm, and the second longitudinal cylinder, so that the side lining is aligned with the arch lining and the installed side lining. Figure 23 As shown, at this time, with the arch lining as the benchmark and referring to the positions of the completed arch lining and side lining, the installation position of the side lining is precisely adjusted to achieve the goal of accurate installation;

[0105] Specific adjustments to the side mounting mechanism include:

[0106] 1) Longitudinal posture adjustment (Y-axis translation)

[0107] The second longitudinal movement cylinder extends and retracts at a low speed, causing the side lining and lining supports to slide slowly on the through beam to achieve longitudinal posture adjustment.

[0108] 2) Lateral posture adjustment (X-axis translation)

[0109] The piston rod of the telescopic arm is extended (retracted) at a low speed, and the second rotary cylinder is slowly retracted (extended) according to the movement of the side lining, so that the side lining moves laterally to achieve lateral posture adjustment.

[0110] 3) Vertical posture adjustment (Z-axis translation)

[0111] The piston rod of the second rotary cylinder is extended (retracted) at a low speed, and the piston rod of the telescopic arm is slowly retracted (extended) according to the movement of the side lining, so that the lining piece moves vertically to achieve vertical posture adjustment.

[0112] 4) Longitudinal angle posture adjustment (rotation around the Y axis)

[0113] The first rotary cylinder extends or retracts at a low speed, causing the side lining, lining support, and through beam to rotate slightly around the hinge shaft on the telescopic arm to achieve longitudinal angle adjustment.

[0114] 5) Horizontal angle adjustment (rotation around the X axis)

[0115] The piston rod of the second rotating cylinder is slowly retracted (extended), and the piston rod of the front telescopic arm cylinder is slowly extended (retracted) according to the movement of the side lining; the middle telescopic arm remains stationary; the piston rod of the second rotating cylinder at the rear end is slowly extended (retracted), and the cylinder piston rod of the telescopic arm is slowly retracted (extended) according to the movement of the lining piece, so that the side lining, lining support and through beam are rotated slightly laterally around the hinge point of the middle telescopic arm as a whole to achieve lateral angle posture adjustment.

[0116] 6) Vertical angle adjustment (rotation around the Z axis)

[0117] The oil cylinder piston rod of the front telescopic arm is slowly extended (retracted), and the piston rod of the second rotary oil cylinder is slowly retracted (extended) according to the movement of the side lining; the middle telescopic arm remains stationary; the oil cylinder piston rod of the rear telescopic arm is slowly retracted (extended), and the piston rod of the second rotary oil cylinder is slowly extended (retracted) according to the movement of the side lining, so that the side lining, lining support and through beam are rotated slightly in the vertical direction around the hinge point of the middle telescopic arm as a whole, so as to realize vertical angle posture adjustment.

[0118] (9) Connect the bolts between the side lining and the arch lining, and then cast the wet joints to equal strength.

[0119] (10) Retract the arch mounting mechanism and the side mounting mechanism to their original positions, and support the walking mechanism on the ground. Figure 24 As shown, the transport and safety integrated machine is moved out of the tunnel for the next cycle of transportation and installation.

Claims

1. A transport and safety integrated machine for lining transportation and installation, comprising at least a frame, an electrical and hydraulic system mounted on the frame, a power compartment, and a traveling mechanism connected to the bottom of the frame. A prefabricated arch wall lining comprises an arch lining and two side lining sections, characterized in that: The frame is equipped with an arch mounting mechanism and a side mounting mechanism, wherein two sets of side mounting mechanisms are symmetrically arranged on both sides of the arch mounting mechanism; The arch lining is installed on the arch installation mechanism, and the arch installation mechanism includes a supporting crossbeam, a lifting crossbeam, a lifting cylinder, a first transverse oil cylinder and a first longitudinal oil cylinder, wherein two lifting crossbeams are provided, and the lifting cylinders are vertically connected between the lifting crossbeam and the vehicle frame so that the lifting crossbeams are transversely installed at the front and rear ends of the vehicle frame; the supporting crossbeam is longitudinally installed on the lifting crossbeam, and the first transverse oil cylinder is installed between the lifting crossbeam and the supporting crossbeam so that the supporting crossbeam moves transversely along the lifting crossbeam; the arch lining is installed on the supporting crossbeam, and the first longitudinal oil cylinder is installed between the arch lining and the supporting crossbeam so that the arch lining moves longitudinally along the supporting crossbeam, so that the arch lining is adjusted and positioned to the arch installation position on three planes; The side lining is installed on the side mounting mechanism, and the side mounting mechanism includes a telescopic arm, a through beam, a lining support, a first rotating oil cylinder and a second rotating oil cylinder, wherein both ends of the telescopic arm are hingedly connected to the through beam and the frame, the first rotating oil cylinder is located at the hinge between the telescopic arm and the through beam, and the first rotating oil cylinder is hingedly connected to the telescopic arm and the through beam, the second rotating oil cylinder is located at the hinge between the telescopic arm and the frame, and the second rotating oil is hingedly connected to the telescopic arm and the frame, the first rotating oil cylinder and the second rotating oil cylinder are telescopically extended and retracted, thereby adjusting the orientation of the through beam; the shapes of the through beam and the lining support are both arc structures matching the shape of the side lining, the lining support is installed on the through beam and connected to the side lining, so that the side lining is installed on the side mounting mechanism, and the side lining is located on the side and lower side of the arch lining. When the side lining is installed, the telescopic arm, the first rotating oil cylinder and the second rotating oil cylinder are extended and retracted to adjust the side lining to the side mounting position.

2. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: The bottom of the frame is also symmetrically installed with more than four sets of whole-machine adjustment mechanisms, which include a support bracket, lifting legs, a sliding beam, a transverse movement assembly and a longitudinal movement assembly, wherein the lifting legs are installed at the four corners of the bottom of the support bracket, and the sliding beam is installed on the support bracket and the frame through the transverse movement assembly and the longitudinal movement assembly.

3. The integrated transport and safety machine for lining transportation and installation according to claim 2, characterized in that: The transverse movement assembly includes a third transverse movement cylinder and a transverse movement slide. The transverse movement slide is fixedly mounted on the upper portion of the support bracket. A transverse movement slot is provided at the bottom of the sliding beam. The transverse movement slot and the transverse movement slide are slidably connected to the sliding beam so that the sliding beam is slidably connected to the support bracket. The third transverse movement cylinder is mounted between the support bracket and the sliding beam. The longitudinal movement assembly includes a third longitudinal movement cylinder and a longitudinal movement slide. The longitudinal movement slide is fixedly installed at the bottom of the frame. A longitudinal movement slide is provided on the upper part of the sliding beam. The longitudinal movement slide and the longitudinal movement slide are slidingly connected, so that the sliding beam frame is slidingly connected to the sliding beam. The third longitudinal movement cylinder is installed between the frame and the sliding beam.

4. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: Both ends of the lifting beam are provided with mounting holes, and guide columns are connected to the mounting holes through ball joints. The bottom of the guide columns is fixedly connected to the frame. When the lifting cylinder lifts the lifting beam, the guide columns limit the lifting beam. The lifting beam is provided with a first guide hole, and the bottoms of both ends of the supporting beam are connected to first sliding tenons, which are respectively connected to the first guide holes of the two lifting beams. The transverse dimension of the first guide hole is larger than the transverse dimension of the first sliding tenon, and the first transverse movement cylinder drives the first sliding tenon to move transversely along the first guide hole; The supporting crossbeam is a box beam structure that is wide at the top and narrow at the bottom. A second guide hole is provided in the middle of the supporting crossbeam. A second sliding tenon is installed corresponding to the bottom of the arch lining. The second sliding tenon is installed in the second guide hole. The longitudinal dimension of the second guide hole is larger than the longitudinal dimension of the second sliding tenon. The first longitudinal movement cylinder drives the second sliding tenon to move longitudinally along the second guide hole.

5. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: Temporary support rods are distributed and connected between the arch lining and the side lining and the vehicle frame.

6. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: There are more than two lining supports, each of which is provided with a slide groove at the bottom. The lining supports are mounted on the through beam by straddling the slide groove, and the lining supports are slidably connected to the through beam. A second longitudinal movement oil cylinder is distributed and connected between the through beam and the lining supports. The second longitudinal movement oil cylinder is extended and retracted to make the lining supports move longitudinally along the through beam. The side lining is installed with a threaded rod and a positioning shaft, the lining support is provided with a threaded hole and a positioning hole, the positioning shaft is installed in the positioning hole, and the threaded rod is connected to the threaded hole, so that the side lining is installed on the side installation mechanism.

7. The integrated transport and safety machine for lining transportation and installation according to claim 6, characterized in that: There are more than two telescopic arms distributed between the same side mounting mechanism and the vehicle frame, and the number and position of the first rotary cylinder and the second rotary cylinder correspond to the telescopic arms.

8. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: The frame is a combined beam structure, including wheel beams, column beams, connecting beams and main cross beams, wherein there are two wheel beams, two connecting beams and two main cross beams, and four column beams. Two wheel beams are arranged in parallel at the bottom, the column beams are connected to the two ends of each wheel beam, the connecting beam is connected to the column beam and is perpendicular to the wheel beam, the main cross beam is connected in parallel between the two connecting beams and the main cross beams are all located above and inside the wheel beams; the side mounting mechanism is installed on the upper surface of the wheel beam, and the arch mounting mechanism is installed on the upper part of the main cross beam and the connecting beam.

9. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: The walking mechanism is a tire-type structure, including a suspension assembly, a wheel group, a steering system and a braking system. The suspension assembly is provided with 10 axis groups and 20 groups, including 3 active suspension axes, 4 driven braking suspension axes and 3 driven non-braking suspension axes. The wheel group includes a driving wheel group, a braking wheel group and a driven wheel group.

10. The integrated transport and safety machine for lining transportation and installation according to claim 1, characterized in that: A driver's cab is provided at both the front and rear ends of the frame.

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