A multi-layer welded wire mesh for ballastless track and its steel bar rolling mechanism

Abstract

This invention discloses a multi-layer welded steel mesh for ballastless track, comprising several layers of steel mesh. Each layer includes several transverse and longitudinal steel bars, with adjacent transverse steel bars equally spaced and adjacent longitudinal steel bars also equally spaced. The transverse and longitudinal steel bars are welded together. A stress-balancing structure is provided on the transverse and / or longitudinal steel bars to ensure balanced stress distribution during transport and handling. This invention makes technical improvements to the multi-layer welded steel mesh for ballastless track, resulting in a more balanced and reasonable stress distribution during loading, unloading, and transport, avoiding deformation and weld detachment, preventing unnecessary external forces or unbalanced forces, and ensuring stability and preventing detachment during loading, unloading, and transport. The rolling mechanism of the steel bars in the multi-layer welded steel mesh changes the original roll drawing state, resulting in almost no tensile stress, which is beneficial for achieving the required plasticity index and surface quality of the steel bars.

Description

Technical Field

[0001] This invention relates to a multi-layer welded steel wire mesh for ballastless tracks and a rolling mechanism for the steel wires thereon. Background Technology

[0002] Ballastless track refers to a track structure that uses a monolithic foundation of concrete or asphalt mixture instead of loose gravel ballast. Also known as ballastless track, it represents the world's most advanced track technology. Compared to ballasted track, ballastless track avoids ballast splashing, offering superior smoothness, stability, service life, durability, and reduced maintenance. Train speeds can reach over 350 km / h. Ballastless track uses a self-stable concrete or asphalt ballast bed to transmit dynamic and static loads during train operation, with the elastic deformation required for operation primarily provided by precisely defined unit materials placed under the rails or fasteners. The structural design of ballastless track requires sufficient frost resistance, particularly regarding subsequent settlement deformation of the substructure after track laying. Therefore, ballastless track lines exhibit good long-term stability, especially under high-speed conditions, and are a type of superstructure requiring minimal maintenance under normal circumstances.

[0003] Reinforcing mesh, also known as welded steel mesh, welded steel wire mesh, welded steel wire mesh sheet, etc., is a mesh sheet in which longitudinal and transverse steel bars are arranged at certain intervals and perpendicular to each other, with all intersections welded together. Welded steel mesh technology has been used in high-speed railways since the Beijing-Tianjin Intercity Railway. From the Beijing-Tianjin Intercity Railway to the four longitudinal and four transverse high-speed railways, welded steel mesh has gradually gained widespread acceptance from design and construction units, from its application in crack-resistant layers of precast box girders to cast-in-place pavement layers of bridge decks, and in the base and self-compacting layer reinforcement of track slabs. The bridge deck of the prestressed concrete simply supported beam with ballastless track is reinforced with anti-crack reinforcement. This reinforcement is optimized from the bridge deck reinforcement of Borg, with spacing values ​​of 225, 214, 222, and 235 mm. The spacing of the reinforcement is complex and difficult to control precisely by hand. Furthermore, according to drainage requirements, the reinforcement needs to be processed into a W shape with a bending angle of only 2°. The use of welded wire mesh technology effectively ensured the placement rate of the bridge deck reinforcement and accelerated the construction progress, receiving unanimous praise from the owner and construction unit. In this model, the welded wire mesh is used as a protective layer for the precast box girder during the prefabrication process to prevent cracking. The successful application of welded wire mesh technology in this project laid the foundation for the application of welded wire mesh in other high-speed railways. The slab track consists of rails, fasteners, base plates, track slabs, CA mortar bedding layer, concrete base, convex abutments, and surrounding resin filling. The welded wire mesh is mainly used in the concrete base. The requirements for the use of welded wire mesh include: when stacking whole bundles of mesh, the stress on the entire surface must be considered to avoid unnecessary external forces or unbalanced forces that could lead to deformation and weld detachment (see Zhu Wensheng's paper "Quality Control and Inspection of Welded Wire Mesh for High-Speed ​​Railways" published in the August 2020 issue of "Technology Application"). Currently, the uneven stress during the loading, unloading, and transportation of multi-layer welded wire mesh can easily lead to problems such as deformation and weld detachment. Patent CN208104907U discloses a reinforcing mesh for a CRTSⅢ type slab track base, comprising an upper layer of welded reinforcing mesh and a lower layer of welded reinforcing mesh, as well as C-shaped reinforcing bars for welding the upper and lower layers together. Both the upper and lower layers consist of two sets of perpendicular reinforcing bars, with the angle between the two sets of bars in the upper and lower layers being 45°. One set of bars in the lower layer is parallel to the extension direction of the track slab, while the other set is perpendicular to the extension direction of the track slab. This patent addresses a reinforcing mesh specifically for CRTSⅢ type slab track bases, meeting high standards for track durability and stability. However, existing technology has not reported on how to meet the requirements for using multi-layer welded reinforcing meshes. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects in the prior art and provide a multi-layer steel welded mesh for ballastless tracks, which ensures that the multi-layer steel welded mesh is subjected to balanced and reasonable force during loading, unloading and transportation, avoids problems such as deformation and weld detachment, avoids being subjected to unnecessary external forces or unbalanced forces, and ensures that the welds are stable and do not fall off during loading, unloading and transportation.

[0005] To achieve the above objectives, the technical solution of this invention is to design a multi-layer welded steel mesh for ballastless tracks, consisting of several layers of steel mesh. Each layer includes several horizontal and vertical steel bars, with adjacent horizontal steel bars spaced equidistantly and adjacent vertical steel bars also spaced equidistantly. The horizontal and vertical steel bars are welded together. A stress-balancing structure is provided on the horizontal and / or vertical steel bars to ensure balanced stress during transport and unloading of the multi-layer welded steel mesh. After setting the stress-balancing structure, inserting a rod between adjacent layers (small-sized rods cause instability in the welded steel mesh during transport and unloading, resulting in uneven stress; large-sized rods (i.e., rod thickness matching the spacing of adjacent layers) cannot be inserted too deeply (due to friction and other issues), causing localized stress on the welded steel mesh), and then adjusting or transferring the multi-layer welded steel mesh, can ensure balanced stress and avoid problems such as deformation and weld detachment.

[0006] A further technical solution is that a stress-balancing structure is set between two adjacent layers of steel mesh in a multi-layer welded steel mesh. The stress-balancing structure is a pair of guide parts fixedly set on the upper and lower adjacent horizontal or vertical steel bars. The guide part is a block shape with a circular arc surface. The pair of guide parts are symmetrically arranged and the circular arc surfaces of the two guide parts are arranged opposite each other. The circular arc surface is adapted to the circumference of the insert rod used to insert between the two adjacent layers of steel mesh.

[0007] A further technical solution is that the guide part is welded to the upper and lower adjacent horizontal or vertical reinforcing bars, and the guide part is equidistant from the two nearest weld points of the reinforcing bars;

[0008] The guide section is located on the horizontal or vertical reinforcing bars at the edge of the multi-layer welded wire mesh. The horizontal and vertical reinforcing bars near the edge have crescent-shaped guide sections, ensuring that the insert rod remains between two adjacent layers. Because the guide section is compatible with the insert rod, the insert rod has no radial freedom after insertion, only axial freedom. This eliminates concerns about lateral swaying of the multi-layer welded wire mesh relative to the insert rod during subsequent handling or transportation, ensuring stability during loading, unloading, and transport.

[0009] A further technical solution involves rotatably mounting ball bearings on the arc surface of the guide section. The ball bearings on the guide crescent facilitate the insertion of the insert rod deep into the multi-layer welded wire mesh. Additionally, baffles are hinged to the transverse or longitudinal reinforcing bars at the edge of the multi-layer welded wire mesh. The hinge axis is located inside the outermost transverse or longitudinal reinforcing bar, at its upper end. The insert rod consists of several transverse and longitudinal insert rods, each with a notch for vertical insertion. After the baffle blocks the insert rod, the notch on the transverse (or longitudinal) insert rod allows the longitudinal insert rod to pass through.

[0010] Another technical solution is that the stress-balanced structure is a cylindrical protrusion set on the top and bottom layers of the multi-layer welded steel mesh, with a circular blind hole-shaped groove set in the center of the protrusion.

[0011] The insert rod used for inserting between two adjacent layers of steel mesh has a pair of rubber cylindrical protrusions that fit into the groove, and the pair of rubber cylindrical protrusions are arranged radially along the insert rod. In this way, after the insert rod is inserted, it is rotated so that the rubber cylindrical protrusions are inserted into the groove, and then the entire multi-layer steel welded mesh can be moved or transported through the insert rod.

[0012] A further technical solution involves placing the protrusions on the reinforcing mesh at the midpoint between two adjacent weld points. These protrusions are positioned on the horizontal and / or vertical reinforcing bars. The top and bottom layers of the reinforcing mesh are integrally or fixedly (welded) with these protrusions, which serve both to indicate the midpoint position of the welded horizontal and vertical reinforcing bars and as a point of leverage during loading, unloading, and transportation.

[0013] The present invention also provides a technical solution for rolling reinforcing bars for multi-layer welded wire mesh for ballastless rails, comprising a machine base, a track on the machine base, a support and a guide ring slidably mounted on the track, a roller on the support, and a guide ring adapted to the reinforcing bar to be rolled. The support is connected to a reduction motor via a transmission mechanism, and the reduction motor is connected to a controller located outside the mechanism. Because the reinforcing bar is subjected to significant tensile stress during cold rolling, resulting in a roll-drawn state, which is detrimental to the plasticity and surface quality of the reinforcing bar, the guide ring (which slides freely on the track) is also pushed and moved laterally when the support (and simultaneously the roller) moves laterally. This changes the original roll-drawn state, almost eliminating tensile stress and improving the plasticity and surface quality of the reinforcing bar.

[0014] A further technical solution involves the rolling mechanism including several movable support feet. Each support foot has casters at its bottom and a semi-groove-shaped support at its upper end to support the reinforcing bar. The support foot furthest from the support frame has an upwardly extending baffle on its support portion. The outermost support foot also has an upwardly extending baffle to hold the reinforcing bar in place, preventing it from shifting or moving during indentation and diameter reduction. The movable support feet can be adjusted according to the length of the reinforcing bar to be rolled. After adjustment, the support feet are fixed in the desired position using fastening bolts.

[0015] The advantages and beneficial effects of this invention are: it ensures that the multi-layer welded wire mesh is subjected to balanced and reasonable force during loading, unloading and transportation, avoids problems such as deformation and weld detachment, avoids being subjected to unnecessary external forces or unbalanced forces, and is stable and does not fall off during loading, unloading and transportation.

[0016] The horizontal and vertical reinforcing bars near the edge have crescent-shaped guides to ensure that the inserts are always between two adjacent layers. Because the guides are compatible with the inserts, the inserts have no radial freedom after insertion, only axial freedom. This ensures that there is no concern about the left and right swaying of the multi-layer welded mesh relative to the inserts during subsequent handling or transportation, thus guaranteeing the stability of loading, unloading and transportation.

[0017] The guide crescent is equipped with ball bearings, which facilitates the insertion of the insert rod into the depth of the multi-layer welded steel mesh.

[0018] The top and bottom layers of steel mesh are integrally or fixedly (welded) with protrusions. The protrusions are used to indicate the midpoint position of the horizontal and vertical steel bars after welding, and also serve as the force points during loading, unloading and transportation.

[0019] Because the steel bars are subjected to large tensile stress during cold rolling, they are in a roll-drawn state, which is not conducive to the plasticity index and surface appearance quality of the steel bars. Therefore, when the support (and of course, the rolls also move laterally) moves laterally, the guide ring (which slides freely on the track) is also pushed and moved laterally. This changes the original roll-drawn state, and the steel bars are almost free from tensile stress, which is conducive to the steel bars meeting the standards for plasticity index and surface appearance quality.

[0020] The outermost support leg has an upwardly extending baffle to hold the reinforcing bar in place, preventing it from shifting or moving during indentation and diameter reduction. The movable support leg can be adjusted to fit the length of the reinforcing bar to be rolled. After adjustment, the support leg is secured in place using fastening bolts. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a first embodiment of a multi-layer welded steel mesh for ballastless track according to the present invention;

[0022] Figure 2 yes Figure 1 A bottom view;

[0023] Figure 3 yes Figure 2 Enlarged schematic diagram of the two guide sections in the middle;

[0024] Figure 4 yes Figure 1 A diagram illustrating the state where the plug is not inserted;

[0025] Figure 5 yes Figure 1 A diagram showing the result after inserting another horizontal insert;

[0026] Figure 6 yes Figure 5 A partially enlarged schematic diagram of the ends of the two insert rods in the side view;

[0027] Figure 7 This is a schematic diagram of the rolling mechanism according to Embodiment 1 of the present invention;

[0028] Figure 8 This is a schematic diagram of Embodiment 2 of the present invention;

[0029] Figure 9 yes Figure 8 Enlarged schematic diagram of components near the central protrusion;

[0030] Figure 10 yes Figure 8 Another schematic diagram of the working state;

[0031] Figure 11 yes Figure 10 Enlarged schematic diagram of the components near the central protrusion.

[0032] In the diagram: 1. Horizontal reinforcing bar; 2. Longitudinal reinforcing bar; 3. Guide part; 4. Ball bearing; 5. Machine base; 6. Track; 7. Support; 8. Roller; 9. Guide ring; 10. Gear motor; 11. Controller; 12. Support foot; 13. Support part; 14. Baffle; 15. Protrusion; 16. Groove; 17. Insert rod; 18. Rubber cylindrical protrusion; 19. Reinforcing bar weld point; 20. Baffle plate; 21. Notch. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1:

[0035] like Figures 1 to 7 As shown (for ease of illustration), Figure 1(Only one longitudinal insert bar is shown). This invention is a multi-layer welded steel mesh for ballastless tracks, consisting of several layers of steel mesh. Each layer of steel mesh includes several horizontal steel bars 1 and vertical steel bars 2. Adjacent horizontal steel bars 1 are equidistant from each other, and adjacent vertical steel bars 2 are also equidistant from each other. The horizontal steel bars 1 and vertical steel bars 2 are welded together. A force-balancing structure is provided on the horizontal steel bars 1 and vertical steel bars 2 to ensure that the multi-layer welded steel mesh is subjected to balanced forces during transportation and unloading. The force-balancing structure is set between two adjacent layers of steel mesh. The force-balancing structure is a pair of guide parts 3 fixedly set on adjacent horizontal steel bars 1 or vertical steel bars 2. The guide parts 3 are block-shaped with a circular arc surface. The pair of guide parts 3 are symmetrically arranged and the circular arc surfaces of the two guide parts 3 are opposite to each other. The circular arc surface is adapted to the circumference of the insert bar 17 used for insertion between two adjacent layers of steel mesh. The guide part 3 is welded to the adjacent horizontal reinforcing bars 1 or vertical reinforcing bars 2, and the guide part 3 is equidistant from the two nearest weld points 19 of the reinforcing bars; the guide part 3 is set on the horizontal reinforcing bars 1 or vertical reinforcing bars 2 at the edge of the multi-layer welded wire mesh. A ball bearing 4 is rotatably mounted on the arc surface of the guide part 3. Both ends are provided with baffles 20 that have only an inward rotational degree of freedom, and the insert rod is provided with a notch 21 for vertical insertion of the insert rod. After the baffles block the insert rod, the notch on the horizontal insert rod (or the vertical insert rod) is just enough for the vertical insert rod to pass through.

[0036] A mechanism for rolling reinforcing bars for multi-layer welded wire mesh of ballastless track 6 includes a base 5, a track 6 mounted on the base 5, a support 7 and a guide ring 9 slidably mounted on the track 6, a rolling mill 8 mounted on the support 7, and a guide ring 9 adapted to the reinforcing bar to be rolled. The support 7 is connected to a reduction motor 10 via a transmission mechanism, and the reduction motor 10 is signal-connected to a controller 11 located outside the mechanism. The transmission mechanism is a screw-nut mechanism, with the nut on the screw-nut mechanism fixedly connected to the support 7, and the screw on the screw-nut mechanism connected to the output shaft of the reduction motor 10. The rolling mechanism also includes several movable support feet 12, with casters at the bottom of the support feet 12 and semi-groove-shaped support parts 13 at the top for supporting the reinforcing bars. A baffle 14 extending upwards is provided on the support part 13 of the support foot 12 furthest from the support 7.

[0037] The working principle is as follows:

[0038] After the geared motor starts, it drives the support to slide. During the sliding process, the support causes the rolling rollers to move horizontally, marking and reducing the diameter of the steel bar. The support feet are fixed to the ground with fastening bolts after being adjusted according to the length of the steel bar. The baffle on the farthest support foot can prevent the steel bar from moving horizontally when the support moves horizontally. When the support moves horizontally, the guide ring is pushed by the support and moves horizontally along with it, which can ensure the stability of the steel bar (the rolled part) during the marking and diameter reduction process.

[0039] When transporting or transferring multi-layer welded wire mesh, inserting the insert rods and adjusting the rods can avoid various problems caused by uneven stress on the welded wire mesh.

[0040] Example 2:

[0041] The difference from Embodiment 1 is that, as Figures 8 to 11 As shown, the stress-balanced structure consists of cylindrical protrusions 15 on the top and bottom layers of the multi-layer welded steel mesh. Each protrusion 15 has a circular blind-hole-shaped groove 16 at its center. A pair of rubber cylindrical protrusions 18, fitted to the grooves 16, are provided on the insertion rod 17 used for inserting between adjacent layers of steel mesh. These protrusions 18 are arranged radially along the insertion rod 17. The protrusions 15 on the steel mesh are located at the midpoint between two adjacent weld points 19, and are positioned on both the horizontal and vertical reinforcing bars.

[0042] The working principle is as follows:

[0043] The protrusion is cylindrical, and a groove is set in the center of the protrusion. The groove is a circular blind hole. A pair of rubber cylindrical protrusions (matching the groove) are set on the surface of the insertion rod. The pair of cylindrical protrusions are set radially along the insertion rod. First, rotate the rod so that the pair of cylindrical protrusions are set horizontally. After inserting it deep enough, rotate it 90° so that the cylindrical protrusions are set vertically, that is, the rubber cylindrical protrusions are inserted into the groove.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multi-layer welded steel mesh for ballastless track, characterized in that, Composed of several layers of steel mesh, each layer includes several horizontal and vertical steel bars. Adjacent horizontal steel bars are equidistant from each other, and adjacent vertical steel bars are also equidistant from each other. The horizontal and vertical steel bars are welded together. A stress-balancing structure is provided on the horizontal and / or vertical steel bars to ensure that the multi-layer welded steel mesh is subjected to balanced forces during transportation and unloading. The stress-balancing structure is set between two adjacent layers of steel mesh. The stress-balancing structure is a pair of guide parts fixedly set on the upper and lower adjacent horizontal or vertical steel bars. The guide parts are block-shaped with a circular arc surface. The pair of guide parts are symmetrically arranged and the circular arc surfaces of the two guide parts are opposite to each other. The circular arc surface is adapted to the circumference of the insert for insertion between two adjacent layers of steel mesh. The guide part is welded to the upper and lower adjacent horizontal or vertical steel bars, and the guide part is equidistant from the two nearest steel bar weld points. The guide portion is provided on the horizontal or vertical reinforcing bars at the edge of the multi-layer welded wire mesh; Rotating balls are provided on the arc surface of the guide portion; The welded steel mesh is provided with baffles at both ends, which have only inward rotational freedom. The insert rod is provided with a notch for vertical insertion. After the baffle blocks the insert rod, the notch on the horizontal or vertical insert rod is just enough for the vertical insert rod to pass through.

2. The multi-layer welded steel mesh for ballastless track according to claim 1, characterized in that, The stress-balancing structure consists of cylindrical protrusions on the top and bottom layers of the multi-layer welded steel mesh, with a circular blind hole-shaped groove at the center of each protrusion. The insert rod used for inserting between two adjacent layers of reinforcing mesh is provided with a pair of rubber cylindrical protrusions that are adapted to the groove, and the pair of rubber cylindrical protrusions are arranged radially along the insert rod.

3. The multi-layer welded steel mesh for ballastless track according to claim 2, characterized in that, The protrusions on the reinforcing mesh are located at the midpoint between two adjacent weld points of the reinforcing bars, and the protrusions on the reinforcing mesh are set on the horizontal and / or vertical reinforcing bars.

4. A steel bar rolling mechanism for rolling multi-layer welded steel mesh for ballastless track as described in claim 1, characterized in that, It includes a base, a track on the base, a support and a guide ring slidably mounted on the track, a roller on the support, the guide ring being adapted to the steel bar to be rolled, the support being connected to a geared motor through a transmission mechanism, and the geared motor being connected to a controller located outside the mechanism.

5. The steel bar rolling mechanism for rolling multi-layer welded steel mesh for ballastless track as described in claim 4, characterized in that, The steel bar rolling mechanism also includes several movable support feet. The bottom of the support feet is equipped with casters, and the upper end is equipped with a semi-groove-shaped support for supporting the steel bars. The support part on the support foot farthest from the bracket is equipped with an upwardly extending baffle.

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