JP5773750B2 - Variable pad - Google Patents

Description

  The present invention relates to a resin injection type variable pad interposed between a rail bottom surface and a tie plate together with a track pad.

  When a rail is fastened to a track slab or PC sleeper, a tie plate is fixed to the track slab or PC sleeper, a rail is mounted on the tie plate with a variable pad and a track pad sandwiched between them, and the rail is held. .

JP 2005-282112 A JP 2006-233477 A JP 2004-169437 A

  Patent Documents 1, 2, and 3 show a flat bag body having a substantially rectangular shape in plan view, in which a pair of upper and lower resin sheets are stacked and sealed at the periphery to form a resin filling chamber therein. A resin inlet and an air vent are formed at diagonal positions of the bag body, and the air injected from the resin inlet is injected into the resin filling chamber, and the internal air is discharged from the air vent.

  In these Patent Documents 1, 2, and 3, a woven fabric reinforcing material (Patent Document 1) and a reinforcing fiber cloth (Patent Documents 2 and 3) made of rigid fibers are stored in advance in the bag body, It has also been shown that the reinforcing material is embedded in the injected resin to cure the resin. Here, glass fiber is used as a woven cloth-like reinforcing material or a reinforcing fiber cloth.

  However, the conventional reinforcing material is a woven cloth or fiber cloth, so the air adhering to the reinforcing material cannot be discharged smoothly during resin injection, and the reinforcing material is usually undulated in the resin-filled chamber. Air accumulates easily in the resin. For this reason, there has been a problem that the resin is cured while air remains in the injected resin, and the strength of the variable pad after the resin is cured is lowered or the durability is adversely affected.

  Further, the resin filling the conventional variable pad becomes a very hard plate shape when cured, and may be broken by a large impact repeatedly applied each time the vehicle passes through the rail due to the looseness of the rail fastening device or the removal of the track pad. For this reason, it is necessary to pay sufficient attention to the inspection and replacement of the variable pad, and there is a problem that it takes time and effort for maintenance. In particular, since the glass fiber used for the conventional variable pad has a low elongation rate, the fiber may break and break apart as the resin breaks. In this case, it may cause a track error or a train swing.

  Furthermore, regarding the handling of glass fiber, according to the “Dust Prevention Regulations” (rules based on the Labor Health Law, Ministry of Labor Ordinance No. 18) and “Guidelines on Occupational Health of Glass Fibers and Rock Wool” (Volatile No. 1), As an asbestos substitute, it is strictly regulated in consideration of the effects on the human body and the environment.

  The present invention has been made in view of such circumstances, preventing air from being mixed into the injected resin to prevent a decrease in the resin strength after curing, increasing impact resistance strength and durability, and reducing maintenance work. It is an object of the present invention to provide a variable pad that can prevent the stiffener from splashing around due to breakage of the variable pad and prevent the legal inconvenience in handling.

According to the present invention, the object of the first aspect is to support the rail load and set the rail height by inserting the resin liquid below the rail, adjusting the thickness according to the injection amount of the resin liquid, and curing the resin liquid. In the variable pad, a resin bag body forming a flat resin filling chamber having a square shape in plan view, a resin inlet opening at a corner of the bag body and guiding the resin into the resin filling chamber, and for injecting the resin Accordingly, an air vent for exhausting air from the resin-filled chamber, and a yarn of any one of polyester fiber, polyethylene fiber, polypropylene fiber, nylon fiber, vinylon fiber, and aramid fiber are formed in a mesh shape, and the intersection of the yarns and a mesh-like reinforcing member housed spread the resin filling chamber of the bag body a obtained by fixing the side length 2 the opening of the mesh-like reinforcing member Variable pad, characterized in that the polygonal 5 mm, is achieved by.

  If one side of the opening is 2 mm or less, the flow of air and resin is not smooth, the probability that bubbles remain in the resin around the mesh-like reinforcing material increases, and the strength and durability of the variable pad decrease. On the other hand, when the thickness is 16 mm or more, there is almost no air bubbles and there is no point in making it larger. On the other hand, the basis weight (amount of use) of the reinforcing material is reduced, so that the strength is reduced as compared with a glass cloth. Accordingly, the length of one side is preferably 2 to 15 mm. The ease of air bubbles and the length of this side are affected by the viscosity of the resin at the time of injection, but two-component mixed polyurethane resin, polyester resin, and vinyl ester resin for variable pads that are normally used are injected. At times (when uncured), the viscosity is small and is about 100 to 150 mPa · s (millipascal second). Therefore, it is considered that it is not necessary to consider the influence of the viscosity because the fluidity is very good.

  The glass fiber conventionally used as a reinforcing material has a high tensile strength (3.9 to 4.7 gf / D) but an extremely low elongation (ductility) (3 to 4%). That is, there is a property that the toughness is small, and it is brittle and easy to break. On the other hand, the resin used for the variable pad is a hard plate when cured, and may crack when subjected to a large impact. For this reason, if the resin breaks due to a large impact, the glass fiber will be easily broken, and this will cause the variable pad to fall apart, making it easier to jump out of the tie plate and cause a gap between the rail and the tie plate. The inventor knew. In addition, it was found that bubbles that were difficult to move due to the reinforcing material and bubbles in the fibers (between fibers) remained in the resin, thereby reducing the durability of the variable pad.

  Therefore, the inventor studied a method for preventing air from being easily discharged from the reinforcing material so that no bubbles remain in the bag after the resin was injected, and as a result, the reinforcing material itself was meshed and the air was pushed by the resin. The idea is to ensure that it can be discharged smoothly. The present invention has been made based on this idea.

Since the reinforcing material has a mesh shape, resin and air can easily flow through the opening. For this reason, even if the reinforcing material undulates, air does not collect on both sides or one side. Accordingly, there is no air remaining in the variable pad, and a decrease in durability of the variable pad due to air mixing can be prevented. Further, by adopting organic fiber having a high elongation rate and good impact resistance as a reinforcing material, even if a large impact is applied and the cured resin is cracked, the fiber is not broken and the variable pad is not easily separated. For this reason, jumping out of the variable pad is prevented, and sudden trajectory deviation and train shaking can be prevented. Furthermore, since organic fibers are used, safety can be ensured without conflicting with laws and regulations such as dust prevention rules during production. In addition, the crossing portion of each yarn is fixed to prevent the yarn from moving, so that a large opening size can be obtained.

  As a reinforcing material used here, instead of glass fiber, any one of polyester fiber, polyethylene fiber, polypropylene fiber, nylon fiber, vinylon fiber, and aramid fiber was formed in a mesh shape. These have a higher elongation (12-34%) than glass fibers (elongation is 3-4%), so they have high impact resistance and toughness. Even if the cured resin breaks, the fibers do not break apart. It is hard to become and does not jump out of tie plate. Therefore, there is no gap between the rail and the tie plate, and sudden track misalignment and train shaking can be prevented.

Sectional drawing of the track fastening apparatus which shows the example of application of one Example of this invention Disassembled perspective view showing the main part with a resin filling path Operation flow chart of rail height adjustment method Diagram showing the configuration of the variable pad Enlarged view of the VV line end face in FIG. A plan view (A) showing an example of a mesh structure and an enlarged perspective view of a stitch (B) Plan view (A) showing another example of mesh structure and enlarged perspective view of stitch (B) Figure showing changes in scale (horizontal axis) and Charpy impact test results (vertical axis)

  The opening of the mesh-like reinforcing material has a side length (mesh) of 2 to 15 mm, but this dimension is the thickness of the thread used (thread thickness) and the fine air contained in the thread. It is necessary to set appropriately according to the characteristics of the yarn such as the amount, compatibility with resin and air. For example, when it is difficult to contain air in the yarn, or when the material is easy to peel off air bubbles or air film from the yarn surface, the mesh can be reduced. When the thread is thin, the mesh can be reduced, but when the thread is thick, the mesh needs to be increased.

In order to make the mesh-shaped reinforcing material an opening having a relatively large opening size , the crossing portion of the fibers is fixed. For this purpose, an appropriate means such as an adhesive or heat welding can be used .

The mesh-like reinforcing material can be, for example, a three-ply weave made of three yarns in a triaxial structure ( claim 2 ). Here, pattern weaving is a weaving method that is used for “sha”, which is a high-class fabric with a texture (or fixing point) visible. The triaxial structure is an equilateral triangular opening surrounded by three threads. Since each side is non-parallel, the resin is hard to bite into the opening and harden the resin, and the strength is reduced. Increase. For this reason, it is easy to integrate with resin and it is possible to give high strength and high elasticity.

  The yarn weaving structure may be a Russell weaving with a relatively large opening. Russell weaving is a well-known weaving method of “jersey” fabric, which has a biaxial structure in which two yarns are knitted as warp and weft, simplifying the loom. Note that the yarn constituting the mesh includes a yarn in which thin fibers are bundled, a string, a narrow band-like cloth (knitting, fabric), and the like.

  FIG. 1 is a sectional view showing an example of a rail fastening device for a track slab to which an embodiment of the present invention is applied (direct connection type 8), and FIG. 2 is an exploded perspective view of the main part with a resin filling system added. FIG. 3 and FIG. 3 are operation flowcharts of the rail height adjusting method.

  In FIG. 1, reference numeral 10 denotes a track slab. This slab 10 is a PC (Prestressed concrete) plate having a length of several meters in the rail length direction, and is positioned and laid on the roadbed. An embedded stopper collar 12 is embedded in the slab 10 at a predetermined position.

  In the figure, reference numeral 14 denotes an iron tie plate having a length of about 18 cm in the rail length direction. The tie plate 14 is positioned and placed on the slab 10 with an insulating plate 16 such as a rubber mat interposed therebetween. The tie plate 14 is fixed to the slab 10 by anchor T-bolts 18 and nuts 20.

  The T-bolt 18 has a T-shaped bolt head 18a at the lower end. The embedding plug collar 12 has a substantially circular cross section so that the bolt head 18a can pass through. The bolt head 18a is inserted into the embedding plug collar 12 from above and rotated by 90 ° so that the bolt head 18a is inserted into the embedding plug collar. 12 is engaged with an engagement portion 12a provided at the bottom of the frame.

  Here, the T-bolt 18 and the tie plate 14 are electrically insulated by an insulating collar 22. The insulating collar 22 has a cylindrical boss portion and a flange portion that expands from the upper end of the boss portion 24 in the outer diameter direction. The insulating collar 22 is manufactured, for example, by injection molding a polycarbonate resin mixed with about 8% by weight of short glass fibers.

  As shown in FIG. 1, the insulating plate 16 and the tie plate 14 are passed through the T bolt 18, and further, an iron cover plate 28, an insulating collar 22, a washer 30, a spring washer 32, and a washer 34 are passed. Finally, the nut 20 is screwed and tightened. Here, the boss portion of the insulating collar 22 enters the bolt hole of the cover plate 28 and the tie plate 14. In this way, the tie plate 14 and the T-bolt 18 are electrically insulated by the insulating collar 22.

  In FIG. 1, reference numeral 36 denotes a rail, which is placed on the tie plate 14 through a resin injection type variable pad 38 and a track pad 40 for adjusting the rail height. The leaf spring 42 that holds the rail 36 is fastened and fixed to the tie plate 14 by bolts 44 and nuts 46.

  Here, the tie plate 14 is integrally formed with projecting walls 48 and 48 for guiding the rail bottom portion. These projecting walls 48, 48 stand with an interval substantially matching the width of the bottom 36 </ b> A of the rail 36. The variable pad 38 and the track pad 40 are laid between the projecting walls 48, 48, and the bottom 36A of the rail 36 is placed thereon. The rail 36 is restricted from moving in the left-right direction (width direction) by both projecting walls 48, 48.

  The projecting walls 48, 48 are formed with notches 50, 50 extending downward in the transverse direction, and a bolt head (not shown) formed in a substantially trapezoidal shape of the bolt 44 is engaged therewith. Match.

  The track pad 40 has a metal plate 52 made of a stainless steel plate and a rubber plate 54 bonded to the lower surface of the metal plate 52. The metal plate 52 is made longer than the length of the tie plate 14 in the rail longitudinal direction, and both end portions sandwiching a portion corresponding to the length of the tie plate 14 protrude in the width direction to form a tongue-like portion 56. The four tongue-like portions 56 are bent at the tip portions thereof downward. These tongues 56 are engaged with the projecting walls 48 and 48 of the tie plate 14 for positioning.

  Next, the variable pad 38 will be described. As shown in FIGS. 4 and 5, the variable pad 38 has a flat and substantially rectangular bag body 38a and a mesh-like reinforcing material 38b spread and spread in the bag body 38a. A resin is injected into the interior of the resin and cured. The variable pad 38 is formed by cutting out a pair of upper and lower sheets having a predetermined shape from a laminate of sheets of polyethylene, polypropylene, EVA, nylon, and the like, and welding the peripheral edges of the upper and lower sheets into a bag shape with a flat inside. A resin filling chamber is formed.

  As shown in FIG. 2, the bag body 38a of the variable pad 38 is a quadrangle that is longer in the rail longitudinal direction than the dimension that fills the space between the projecting walls 48 of the tie plate 14. An inlet 58 and an air vent 60 are formed. The injection port 58 is in the form of a narrow passage that extends substantially diagonally outward. A one-way valve 58 a that allows the injection of resin is attached to the injection port 58. Moreover, the air vent 60 protrudes in the rail longitudinal direction. A long plug 60a is loaded in the air vent 60 along the passage.

  The filling plug 60a is made of, for example, stick-shaped cotton, and is easy to pass air in the longitudinal direction and difficult to pass resin liquid. The plug 60a can be loaded into the air vent 60 by fusing both sheets between a pair of upper and lower sheets when making the variable pad 38.

  In the bag main body 38a, the mesh-shaped reinforcing material 38b according to the present invention is accommodated. This mesh-like reinforcing material 38b is formed by forming a mesh, which is a polyester fiber, polyethylene fiber, polypropylene fiber, nylon fiber, vinylon fiber, or aramid fiber, knitted into a narrow band or string. . 6 and 7 show examples of the structure of the mesh. FIG. 6A is a plan view showing a structure of a three-ply weave made of three threads in a triaxial structure, and FIG. It is an expansion perspective view of a stitch structure. FIG. 7A is a plan view showing a biaxial structure Russell weave structure in which two vertical and horizontal yarns are knitted, and FIG. 7B is an enlarged perspective view of the stitch structure.

  The triaxial structure shown in FIG. 6 is obtained by forming an equilateral triangular opening 38d surrounded by three threads 38c. Since each side is non-parallel, the resin that bites into the opening and hardened is well-resined. It becomes difficult to peel off and the strength increases. For this reason, it is easy to integrate with resin and it is possible to give high strength and high elasticity. The yarn weaving structure may be a Russell weaving in which the openings 38d 'formed by the vertical and horizontal yarns 38c' are square or rectangular, like a mesh-like reinforcing material 38b 'shown in FIG. This structure simplifies the loom and is easy to manufacture. Further, the crossing portions 38e and 38e 'of the respective yarns are fixed in order to prevent the yarns from moving. For example, the crossing portions 38e and 38e ′ are fixed with an adhesive or fixed by thermocompression bonding.

  The mesh-like reinforcing members 38b and 38b '(hereinafter simply referred to as 38b including those in FIG. 7 are the same for 38c', 38d ', and 38e'). It is thermally welded to the lower surface by a heat welding part 39 (FIGS. 4 and 5). The heat welded portion 39 prevents the mesh-like reinforcing material 38b from moving when the resin is injected from the resin injection port 58, or turning up or bending near the injection port 58.

  The track pad 40 is overlaid on the variable pad 38 (FIGS. 1 and 2). At this time, both end portions of the track pad 40 protrude to both sides of the tie plate 14, and the tongue 56 engages with both end surfaces of the tie plate 14, that is, both end surfaces of the projecting walls 48, 48 (see FIG. 1). Thus, since the four tongue-like portions 56 engage with both end faces of the projecting walls 48, 48, the track pad 40 is accurately positioned. In other words, the tongue 56 functions as a stopper that restricts the movement of the track pad 40.

  The rail height is adjusted while the rail 36 is placed on the track pad 40. In this operation, the rail 36 is held at a predetermined height by using a spacer, a height adjusting block, a jack, a hoisting machine, etc., which will be described later. In this state, the resin liquid is injected from the injection port 58, and the air is discharged from the air After passing through the 60 plugs 60a to the atmosphere, the resin liquid is injected in a state of closing the plugs 60a. The resin is injected by the resin filling device 70, and the rail is supported at a predetermined height by the amount of resin to be filled. Since the one-way valve 58a is attached to the injection port 58, the resin does not flow backward. The resin hardens after a predetermined time.

  Next, the resin filler 70 will be described with reference to FIG. The resin filling device 70 includes an airtight tank (accommodating tank) 72 that accommodates the main agent, an airtight tank (accommodating tank) 74 that accommodates the curing agent, and supplies air pressure to the tanks 72 and 74 to supply the main agent and the curing agent. An air pump (resin supply pump) 76 for sending out, a resin injection gun 78 for injecting the sent resin into the bag body, and a controller (not shown) for driving the pump 76 are provided. When a polyester resin is used here as the filling resin, the main agent is a polyester resin added with cobalt and a curing accelerator, and the curing agent is a polyester resin added with an organic peroxide.

  The resin injection gun 78 is a mixer (nozzle) such as a static mixer. The resin injection gun 78 has a nozzle holder 78 a with a cock (open / close valve, not shown) and a rod-shaped nozzle portion 78 b, a main agent discharged from the tank 72, and a curing agent discharged from the tank 74. Are uniformly mixed and discharged from the rod-shaped nozzle portion 78b.

  Next, a method for adjusting the rail height using the resin filler 70 will be described. In FIG. 1, the rail 36 is first released from the tie plate 14. That is, the nut 46 is loosened from the tie plate 14 and the leaf spring 42 is removed. A height adjusting tool (not shown) such as a height adjusting block serving as a spacer is sandwiched between the rail 36 and the slab 10, and the height of the rail 36 is set to a predetermined height (for example, a target height). (FIG. 3, step S200). Instead of sandwiching the height adjustment block, the rail 36 may be lifted and held using a jack or a hoisting machine.

  In this state, there is a gap below the rail bottom 36A, so the track pad 40 is pushed up, and the bag of the variable pad 38 before resin filling is inserted under it (step S202). Then, the resin filling device 70 described in FIG. 2 is used to fill the bag of the variable pad 38 with resin (step S204). In filling the resin, first, the rod-shaped nozzle portion 78b of the resin injection gun 78 is inserted into the injection port 58 of the variable pad 38 and fixed. When the tanks 72 and 74 are pressurized with the pump 76 in this state, the main agent and the curing agent are sent to the resin injection gun 78.

  The main agent and the curing agent are uniformly mixed by the resin injection gun 78 and flow into the variable pad 38. At this time, since the resin passes through the one-way valve 58 a provided at the injection port 58, the mixed resin does not flow back from the variable pad 38 to the resin injection gun 78. A part of the resin contained in the bag body 38a is divided into the upper and lower surfaces of the mesh-like reinforcing member 38b while bypassing the heat-welded portion 39 of the mesh-like reinforcing member 38b, and flows as indicated by arrows in FIG.

Here, the mesh-like reinforcing member 38b is obtained by forming the yarn into a mesh shape and fixing the crossing portion of the yarn , and has an opening (mesh size) of 2 to 15 mm. For this reason, as the resin flows in, the air in the resin filling chamber freely flows through the opening, so that it does not accumulate on the front surface or the back surface of the mesh-like reinforcing material 38b and enter into the resin of the variable pad 38 in the form of foam. The mesh-like reinforcing material 38b is heat-welded to the bag body 38a at the heat-welding portion 39, and the resin flows freely through the mesh opening, so that the resin does not fold or crease the mesh-like reinforcing material 38b. The resin can be cured in a state where the mesh-shaped reinforcing material 38b is spread uniformly without being unevenly distributed in the resin. For this reason, the strength of the variable pad 38 can be improved and its durability can be increased.

  When the mixed resin is injected into the variable pad 38, the air in the variable pad 38 is pushed out into the atmosphere from the air vent 60 through the plug 60a. Since the plug 60a has a small pressure loss (passage resistance) with respect to air, the air is smoothly discharged. When the air is completely removed, the resin liquid in the variable pad 38 enters the air vent 60, and the resin liquid enters the plug 60a.

  Since the filling plug 60a has a very large pressure loss (passage resistance) with respect to the resin liquid, the resin liquid only penetrates into the filling plug 60a from the bag body 38a side and does not pass therethrough. Further, the soaked resin liquid is not only captured by the filling plug 60a and blocks the vent hole of the filling plug 60a, but also the hardening of the resin liquid captured here in the filling plug 60a proceeds promptly. Therefore, the plug 60a completely closes the air vent 60.

  Thereafter, the resin liquid is further pressed into the variable pad 38 by driving the air pump 76. For this reason, the thickness of the variable pad 38 increases. When the thickness is such that the gap between the rail 36 and the tie plate 14 is eliminated, the cock (open / close valve) of the resin injection gun 78 may be closed and the rod portion 78b of the resin injection gun 78b may be removed from the injection port 58. The mixed resin that has entered the variable pad 38 is cured by being left for a while (step S206). In this way, different variable pads 38 may be sequentially filled with resin.

  After the resin is cured, the rail height adjuster is removed (step S208). Further, after the resin is cured, the resin injection port 58 and the air vent port 60 are cut and removed near their roots (step S210). When the work is finished, the resin injection gun 78 is removed and cleaned. That is, it is necessary to remove the mixed resin before the main agent and the curing agent are cured in the resin injection gun 78.

Comparative example

  Next, Table 1 shows the results of an experiment on how the effect of using the mesh-like reinforcing material 38b according to the present invention varies depending on the type of yarn.

  In Table 1, all of the test examples (A) to (G) use a polyester resin as a resin filled in the resin filling chamber. Among these, (E), (F), and (G) When the mesh-like reinforcing material according to the invention is combined, (A) to (D) are combined with a reinforcing material of cloth (cloth-like or woven-like) for comparison, that is, a reinforcing material having a mesh of 0 to 2 mm or less. This is the case. Moreover, (E) is a case where a reinforcing material having a mesh size of 20 mm is used, although it is a mesh-like reinforcing material. The filling resin used in these test examples (A) to (G) is a polyester resin “AP-104” (trade name) sold by the applicant (Allen Co., Ltd.).

Further, the glass cloth used in Test Example (A) is Nittobo Co., Ltd. glass cloth # 350, which is a product WF350 / 100BS6 (weight per unit area 328 g / m ² ). The mesh of this glass cloth is 0-2 mm.

Polyester cloth NC-300 used in Test Example (B) is manufactured by Nippon Wide Cloth Co., Ltd. and has a basis weight of 320 g / m ² . Aramid cloth AK-20 / 20 used in Test Example (C) is manufactured by Fivex Corporation and has a basis weight of 325 g / m ² . Vinylon cloth UV-200 used in Test Example (D) is manufactured by Unitika Ltd. and has a basis weight of 220 g / m ² . These scales are also 0-2 mm. The triaxial aramid mesh used in Test Example (E) is a product Technora ATT200 manufactured by Teijin Ltd., and has a basis weight of 28 g / m ² and a mesh of 20 mm.

The triaxial vinylon mesh of Test Example (F) is trade name Trineo TSS-1810 manufactured by Unitika Ltd., and its basis weight is 88 g / m ² and the mesh is 10 mm. The biaxial polyester mesh of Test Example (G) is T-200G manufactured by Maeda Kosen Co., Ltd., its basis weight is 300 g / m ² , and the scale is 4.5 × 5.0 (vertical × horizontal) ).

  The Charpy impact test was conducted by a method according to JISK6911 and JISK7111. In Table 1, “resin cracks but does not break (above the measurement limit)” means that the resin cracks at a strength sufficiently larger than the required strength required for the variable pad, but at this time it is reinforced with fibers, so it breaks apart It shows a state of not destroying. “◯” in the “air reservoir state” indicates a state where there is no air reservoir (a state where bubbles are not visually recognized), and “Δ” indicates a state where a small air reservoir is partially observed.

  From these test examples, according to the cases (F) to (G) according to the present invention, sufficient strength is obtained, and at the same time, even if it is cracked, it does not fall apart. Safety was confirmed without conflict. This is because the mesh-like reinforcing material 38b makes the “air reservoir state” ◯, and there is no large air bubbles, and the cured strength of the resin is increased, and organic fibers are used instead of glass fibers as the reinforcing material. it is conceivable that. Further, according to Test Example (E), if the mesh size is large even when the mesh-like reinforcing material is used, it is considered that the reinforcement hardening is lowered because the strength is weaker than that of the glass cloth due to the decrease in the basis weight.

  FIG. 8 shows test examples (E) and (F) in Table 1 with scales on the horizontal axis and strength (Charpy test results) on the vertical axis. From this figure, the strength decreases as the mesh size increases, so the minimum strength required for the variable pad is 10.9, which is the strength when using the glass cloth of Test Example (A), and beyond this strength The required mesh size was about 15 mm with a little margin. Based on this result, in the present invention, the scale range is 2 to 15 mm.

14 Tie plate 36 Rail 38 Variable pad 38a Bag body 38b, 38b 'Mesh reinforcement 38c, 38c' Thread 38d, 38d 'Opening 38e, 38e' Crossing part (adhering part)
39 Heat-welded part 40 Track pad 58 Resin injection port 58a One-way valve 60 Air vent 70 Resin filling device

Claims (2)

In a variable pad that is inserted below the rail, adjusts the thickness according to the injection amount of the resin liquid, and cures the resin liquid to support the rail load and set the rail height,
A resin bag body forming a flat resin filling chamber having a square shape in plan view;
A resin inlet opening in the corner of the bag body and guiding the resin into the resin filling chamber;
An air vent for discharging air from the resin filling chamber as the resin is injected;
One of polyester fiber, polyethylene fiber, polypropylene fiber, nylon fiber, vinylon fiber, and aramid fiber is formed in a mesh shape and the crossing portion of the yarn is fixed, and the bag body is filled with the resin. A mesh-like reinforcing material accommodated in an expanded manner;
The variable pad is characterized in that the opening of the mesh-like reinforcing material is a polygon having a side of 2 to 15 mm. 2. The variable pad according to claim 1 , wherein the mesh-shaped reinforcing material is a three-pattern weave made of three yarns having a triaxial structure .

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