JP4168011B2 - Variable pad - Google Patents

Description

  The present invention relates to a variable pad inserted between a rail and a rail support such as a tie plate or sleeper.

Conventionally, a track pad and a variable pad are inserted between a rail and a rail support such as a tie plate or sleeper with the track pad on the upper side and the variable pad on the lower side at predetermined intervals in the rail direction, for example, every 60 cm. And the technique of supporting a rail via them is known.
For example, these techniques are disclosed in Patent Document 1 and Patent Document 2 below.

Here, the track pad is a member made of an elastic plate such as rubber, and serves as a cushioning material when the train travels on the rail. The cushioning action prevents noise, and the rail support body such as the tie plate from the rail. It prevents the vibration from being transmitted to the installation surface via the door or improves the ride comfort of the passengers in the train.
On the other hand, the variable pad has a bag shape, and functions to hold the rail horizontally and at an appropriate height by injecting a liquid curable resin into the bag and thereafter curing.

FIG. 16 shows an example of the track pad and the variable pad together with the peripheral portion in the construction completed state.
In the figure, reference numeral 200 denotes a rail, and 202 denotes a concrete base, and a metal tie plate (rail support) 204 is fixed on the concrete base 202 via bolts 206 via an insulating plate 208.
Here, the bolt 206 is screwed into an embedded plug 209 embedded in the concrete base 202.

The tie plate 204 is provided with a pair of projecting portions 210 projecting at intervals corresponding to the width of the base portion 200A of the rail 200, and between the projecting portions 210 and 210, the base portion 200A of the rail 200 is provided. Is inserted and positioned.
A rail spring 212 for fixing the rail is attached to each protrusion 210 with a bolt 214 and a nut 216, and the free end of the leaf spring 212 presses the base portion 200 </ b> A of the rail 200 downward.

Between the rail 200 and the tie plate 204, a track pad 218 made of an elastic plate and having a buffering action during train traveling, and a bag-like variable pad 220 are inserted.
A liquid curable resin is injected into the variable pad 220 and then cured.
The variable pad 220 increases its thickness by expansion in accordance with the amount of liquid resin injected, and the rail 200 is held at an appropriate height and level together with the track pad 218 by appropriately adjusting the thickness.

FIG. 17 shows a state before the bag-like variable pad 220 is inflated.
Before the variable pad 220 is inflated, the rail 200 is height-adjusted in advance by a rail height adjusting spacer 222 shown in FIG. 18, so that the variable pad 220 is inflated as shown in FIG. , A gap S is generated between the rail 200 and the track pad 218.
The variable pad 220 is inflated by injecting a liquid resin into the variable pad 220 until the gap S is filled in this state, and the resin injected in this state is cured, so that the rail 200 is adjusted to a height adjusted in advance. Hold.

Here, a SUS steel plate is fixed as a sliding plate 224 on the upper surface of the track pad 218, and the base portion 200A of the rail 200 is brought into contact with the sliding plate 224.
Here, the sliding plate 224 slides the rail 200 on the upper surface of the sliding plate 224 when the rail 200 is expanded or contracted by heat, so that the track pad 218 and the variable pad 220 are moved by the position movement due to the expansion and contraction of the rail 200. It functions to prevent deformation, displacement from the rail support such as the tie plate 204, or detachment in some cases.

FIG. 19 shows a construction procedure for the track pad 218 and the variable pad 220.
In order to insert the track pad 218 and the variable pad 220 into the space between the rail 200 and the tie plate 204 as shown in FIG. In this state, the track pad 218 and the variable pad 220 are arranged in the rail direction in the space between the pair of protrusions 210 and 210 of the tie plate 204 and between the rail 200 and the upper surface of the tie plate 204. Insert into.

Here, the variable pad 220 has conventionally been formed into a bag shape by heat-sealing two resin sheets at the peripheral portion, and this is dimensioned in the width direction when it is inflated in the thickness direction by injecting resin into the inside. Shrink. In the drawing, reference numeral 232 denotes a heat seal portion.
The variable pad 220 is required to have an appropriate width equivalent to the track pad 218 in the contracted state. Therefore, the variable pad 220 has a dimension in the width direction before the liquid resin is inflated by injecting the liquid resin. The dimension is larger than the dimension between 218 and the pair of protrusions 210 and 210 in advance.

Accordingly, the variable pad 220 cannot be inserted between the protrusions 210 and 210 as it is, and therefore, the both ends in the width direction are bent in advance as shown in FIG. 19, and the track pad 218 and the variable pad 220 are in that state. Are inserted between the pair of protrusions 210 and 210.
The state in which the track pad 218 and the variable pad 220 have been inserted in this way is the state shown in FIG. 17. In this state, a liquid resin is injected into the variable pad 220 and then cured.

  Here, the insertion work is performed in a state where the track pad 218 and the variable pad 220 are vertically aligned in advance. When one of the track pads 218 and the variable pad 220 is inserted first, the other is inserted. This causes misalignment, and it becomes difficult to set both the track pad 218 and the variable pad 220 at appropriate positions. Therefore, the two are aligned and inserted simultaneously.

However, it is necessary to insert the track pad 218 and the variable pad 220 which are separated from each other vertically and align them so that one of them is not displaced with respect to the other during the insertion operation. It involves a lot of trouble.
Therefore, the work is inevitably slowed down and the time required for the work is also lengthened.
Further, at that time, the wide variable pad 220 must be inserted in a state of being bent at both ends in the left and right width directions, which makes the insertion operation more difficult.

Japanese Patent Publication No. 48-5644 No. 4-5532

  With this background, the present invention can reduce the labor and time required to insert the variable pad when constructing the variable pad and the track pad, and the work can be performed speedily and the construction cost can be reduced. The purpose of this is to provide a variable pad that can be made inexpensive.

  Thus, in the first aspect of the present invention, a bag-like shape is inserted between the rail and a rail support such as a tie plate together with a track pad made of an elastic plate and with the track pad facing upward. A variable pad that swells in the vertical direction by injecting a liquid curable resin into the interior to fill the gap under the rail, and holds the rail at an adjusted height by hardening the injected resin. The flexible membrane is folded, and the flexible membrane is flexibly deformed in the vertical direction, so that the vertical stretchable portion is oriented in the horizontal direction. It is characterized by being provided in a standing state in an overlapping form.

  According to a second aspect of the present invention, in the first aspect, the stretchable portion provided in a standing state along the peripheral edge portion forms a holding recess for the track pad inside, and the track pad is provided in the holding recess. Can be accommodated.

  According to a third aspect of the present invention, in any one of the first and second aspects, the track pad is integrated.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the front end portion and the rear end portion protrude forward and rearward from the rail support in an inserted state between the rail and the rail support. In addition, at least the front and rear protrusions are formed flexibly with respect to the track pad, and the front and rear protrusions bulge downward by liquid resin injection so that the rail is supported. The body is sandwiched from the front and back.

Effects and effects of the invention

  As described above, the present invention has a form in which the flexible film is folded along the peripheral edge of the variable pad, and the flexible film is flexibly deformed in the vertical direction, so that the vertical stretchable part is stretched. These flexible membranes are provided in an upright state in such a manner that the flexible films are oriented vertically and overlap in the horizontal direction. In the variable pad of the present invention, a liquid resin is injected inside to inflate it vertically. However, the dimension in the left-right direction does not change substantially. Therefore, in the shape before the variable pad is inserted between the rail and the rail support body, the dimension in the left-right direction (perpendicular to the rail) is a pair of protrusions. It is not necessary to make it larger than the dimension between the parts. Therefore, when inserting the variable pad between the rail and the rail support body, it is possible to save the trouble of inserting the bent pad after bending the left and right ends. Pad insertion workability Becomes good, it can be reduced and labor and time required for the insertion operation.

  As a result, the variable pad can be inserted speedily, the time for the insertion work can be shortened, and the construction cost can be reduced.

  According to a second aspect of the present invention, a holding recess for the track pad is formed inside the stretchable portion provided in a standing state along the peripheral edge of the variable pad, and the track pad can be accommodated therein. According to the second aspect, the track pad can be inserted between the rail and the tie plate or the like in a state where the track pad is received and held in the holding recess by the variable pad. Therefore, the labor and time required for the insertion of the track pad and the variable pad can be further reduced, and the construction cost including the track pad insertion can be further reduced compared to the conventional case.

In this case, the track pad can be integrated with the variable pad.
By doing so, it is possible to satisfactorily prevent the track pad and the variable pad from being displaced from each other during the insertion, and to finally insert and set them at an appropriate position.

According to a fourth aspect of the present invention, the front end portion and the rear end portion of the variable pad are protruded forward and rearward from the rail support, and at least the front and rear protrusion portions are formed flexibly with respect to the track pad. By projecting liquid resin into the interior, the front and rear protrusions bulge downward, and the rail support is sandwiched from the front and rear.
In this way, even when the rail is displaced in the rail direction due to expansion and contraction, the variable pad can be prevented from being displaced forward and backward with respect to the rail support body. Can be prevented from coming off the rail support in some cases.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
First, FIG. 1 shows a variable track pad 10 in which the track pad 32 is integrated with the variable pad 34 of the present embodiment in a completed state.
In the figure, 12 is a rail, 14 is a concrete base, 16 is a metal tie plate (rail support), and 18 is an insulating plate.
The tie plate 16 is fixed to the upper surface of the concrete base 14 via an insulating plate 18 with bolts 20.
Here, the bolt 20 is screwed into an embedded plug 22 embedded in the concrete base 14.

Reference numeral 24 denotes a pair of protrusions provided on the tie plate 16, and a plate spring 26 for fixing the rail is attached thereto by bolts 28 and nuts 30.
The base portion 12A of the rail 12 is fitted and positioned between the pair of projecting portions 24 and 24, and the base portion 12A is pressed downward at the free end portion of the leaf spring 26.
The base portion 12 </ b> A of the rail 12 is elastically supported by the tie plate 16 through the variable track pad 10.
Reference numeral 46 denotes a sliding plate made of a SUS steel plate.

2 to 7 show a specific configuration of the variable track pad 10 of the present embodiment (however, a state before construction).
First, as shown in FIGS. 4 and 5, the variable track pad 10 includes a track pad 32 made of a rubber plate (elastic plate) and a variable pad 34 having a bag shape.
Grooves 36 extending in the front-rear direction are formed on the upper surface of the track pad 32 at a predetermined pitch in the left-right direction, as shown in FIGS.

In the present embodiment, the lower surface portion of the track pad 32 constitutes the upper surface portion 35 of the variable pad 34 at the same time.
That is, in this embodiment, part of the track pad 32 forms part of the variable pad 34 at the same time.

As shown in FIGS. 6 and 7, a recess 40 is formed between the plurality of protrusions 38 on the upper surface portion 35 of the variable pad 34, and the recess 40 corresponds to the lower surface portion 42 of the variable pad 34. The concave and convex portions 44 are fitted to the corresponding convex portions 44 formed on the upper surface.
Specifically, the concave portion 40 and the convex portion 44 are uneven in a state where the upper surface portion 35 and the lower surface portion 42 of the variable pad 34 overlap each other before the liquid curable resin described later is injected into the variable pad 34. Thus, the upper surface portion 35 and the lower surface portion 42 are prevented from shifting.

In FIG. 6, reference numeral 48 denotes a half constituting the lower half of the variable pad 34 made of a thin rubber sheet molded product, and a thin flexible film 50A is formed integrally along the peripheral edge of the lower surface portion 42. ing.
On the other hand, rubber flexible films 50B and 50C (see a partially enlarged view of FIG. 4) folded in a U-shaped cross section as a whole are integrally formed on the periphery of the track pad 32 made of a rubber plate.
Specifically, the flexible film 50B extends downward from the peripheral edge of the upper end of the track pad 32, and the flexible film 50C extends upward so as to be folded at the folded portion 54.

Here, the flexible films 50 </ b> B and 50 </ b> C are formed in an annular shape along the periphery of the track pad 32.
The upper end portion 52 (upper joint portion) of the flexible membrane 50C extending upward is bonded and fixed to the upper end portion 56 (lower joint portion) of the flexible membrane 50A where the half body 48 stands.

In the present embodiment, the flexible films 50A, 50B, and 50C constitute a vertically extending and contracting portion 50 that stands up along the peripheral edge of the variable pad 34, and each of the flexible films 50A, 50B, and 50C In the state of being oriented in the vertical direction, it is folded in the horizontal direction.
As a result, when the liquid resin is injected into the variable pad 34, the flexible films 50A, 50B, and 50C of the folded (folded) stretchable portion 50 are flexibly deformed in the vertical direction, thereby changing the variable pad 34. Expands in the vertical direction, increasing the thickness.
In this embodiment, the expansion / contraction part 50 forms the holding recess 51 (partial enlarged view of FIG. 4) of the track pad 32 in the inside, and the track pad 32 is accommodated there.

In the present embodiment, the variable pad 34 has a dimension in the front-rear direction larger than the dimension in the front-rear direction of the tie plate 16. Specifically, the front end portion and the rear end portion protrude from the tie plate 16 before and after.
As shown in FIG. 5, the front and rear end protruding portions 66 are provided with recesses 58, and the recesses 58 form a resin reservoir 60.
As shown in the partially enlarged view of FIG. 4, a small-sized resin reservoir 60 is also provided between the track pad 32 made of a rubber plate and the flexible film 50B on the right side and the left side of the variable pad 34. Is formed.

  As shown in FIG. 2, the variable pad 34 is provided with an inlet 62 for injecting a liquid resin into the variable pad 34 and an exhaust port 64 for discharging the internal air at that time. In addition, the inlet 62 and the exhaust port 64 are provided on the same side in the rail direction with respect to the tie plate 16 of FIG.

Then, as shown in FIG. 6, the respective half halves 62A, 64A of the inlet 62 and the exhaust port 64 are on the track pad 32 side, and the other half halves 62B, respectively of the inlet 62 and the exhaust port 64 are provided. 64B is integrally formed on the side of the half body 48 constituting the lower half of the variable pad 34.
These half bodies 62A, 62B and 64A, 64B form the inlet 62 and the exhaust port 64 when they are combined with each other when the track pad 32 and the variable pad 34 are integrated.

Next, the operation of the variable track pad 10 of this embodiment will be described below together with the construction procedure.
FIG. 8 (I) shows a state in which the tie plate 16 is laid. Thereafter, as shown in FIG. 8 (II), the rail 12 is fitted between the pair of protrusions 24 and 24 of the tie plate 16. After the height is adjusted, a spacer 68 is inserted between the base portion 12A of the rail 12 and the concrete base 14 to temporarily fix the rail 12 to the adjusted height.
At this time, a space exists between the rail 12 and the tie plate 16.

  After adjusting the height of the rail 12 and temporarily fixing it with the spacer 68 in this way, the variable track pad 10 is placed in the rail direction between the protrusions 24 and 24 of the tie plate 16 as shown in FIG. insert.

  In the present embodiment, the variable pad 34 can be changed in thickness in the vertical direction by the expansion / contraction part 50 without particularly changing the horizontal dimension. Therefore, the variable pad 34 has its left and right dimensions projected in advance. The dimension between 24 and 24 can be approximately the same (or slightly smaller dimension).

In the variable track pad 10 of the present embodiment, the track pad 32 and the variable pad 34 have an integral structure. Therefore, when the track pad 32 and the variable pad 34 are inserted between the protrusions 24 and 24 in the rail direction, they are separated. Compared to the case of a body, they can be easily inserted together without worrying about misalignment.
In addition, after the insertion, the entire relative position between the track pad 32 and the variable pad 34 can be kept in the proper relationship position, and the whole can be set in the insertion set state at the proper position.

In the state in which the variable track pad 10 is inserted between the protrusions 24 and 24 in this way, there is a gap between the track pad 32 and the base portion 12A of the rail 12 as shown in FIG. 9 (III). S is present.
This gap S is a gap of about 3 to 14 mm.

Next, a liquid resin is injected into the variable pad 34 through the injection port 62.
As this liquid resin, a two-component mixed reaction curable resin can be used.
The liquid resin is injected until the liquid resin flows out from the exhaust port 64 on the same side as the injection port 62.

The outflow of the liquid resin from the exhaust port 64 occurs when the variable pad 34 swells in the vertical direction due to the injection of the liquid resin and the gap S between the variable track pad 10 and the rail 12 becomes zero.
In other words, the time when the liquid resin starts to flow out from the exhaust port 64 is when the gap S becomes zero.
Therefore, the injection of the liquid resin is stopped at that time. FIG. 9 (IV) shows the state at this time.

The expansion of the variable pad 34 due to the injection of the liquid resin extends as shown in the partial enlarged view of FIG. Specifically, this is performed especially when the flexible film 50C is flexibly deformed in the vertical direction.
Therefore, as a whole, the width in the left-right direction of the variable pad 34 does not change particularly small with expansion due to the injection of the liquid resin.
In other words, the width dimension of the variable pad 34 is adjusted in advance to the dimension between the protrusions 24 and 24 in the tie plate 16 so that the width dimension of the variable pad 34 is not reduced by injection of liquid resin. Can do.

  As described above, the variable track pad 10 of the present embodiment is such that the front and rear ends of the variable pad 34 protrude from the front and rear of the tie plate 16, respectively, and the lower surface 42 of the variable pad 34 is thin. Further, since the resin reservoir 60 is formed at the front and rear end portions of the rubber sheet molded product, the protruding portion 66 is generated by the pressure of the liquid resin injected into the variable pad 34. Bulges downward as shown in FIG. 12, and the tie plate 16 is sandwiched from the front and rear.

Now, after injecting the liquid resin in this way, it is cured. Here, the rail 12 adjusted to an appropriate height is held at the adjusted height by the variable track pad 10.
After the curing of the resin, the concave portion 40 of the upper surface portion 35 is concavo-convexly fitted into the convex portion of the resin generated during the curing, and the convex portion 44 of the lower surface portion 42 is also concavo-convexly fitted into the concave portion generated during the curing of the resin. Thus, after the resin is cured, the upper surface portion 35 and the lower surface portion 42 are prevented from being displaced on the basis of the uneven fitting.
When the support force for the rail 12 is generated in the variable track pad 10 in this way, the rail height adjusting spacer 68 is removed as shown in FIG.

As described above, in this embodiment, even if liquid resin is injected into the variable pad 34 and inflated in the vertical direction, the horizontal dimension of the variable pad 34 does not substantially change. In the shape before the insertion of 34, it is not necessary to make the dimension in the left-right direction (perpendicular to the rail) larger than the dimension between the pair of protrusions 24. When inserting between them, it is not necessary to bend and insert the left and right end portions, and the insertion workability of the variable pad 34 is improved, and the labor and time required for the insertion work can be reduced.
Thereby, the insertion of the variable pad 34 can be performed quickly, the time for the insertion work can be shortened, and the construction cost can be reduced.

  In this embodiment, since the track pad 32 is integrated with the variable pad 34 and the track pad 32 is received and held in the holding recess 51 of the variable pad 34, they can be inserted between the rail 12 and the tie plate 16. Further, not only the variable pad 34 but also the track pad 32 can be easily inserted, and the labor and time required to insert the track pad 32 and the variable pad 34 can be further reduced. The pad 34 can be inserted more speedily, and the construction cost including the insertion of the track pad 32 can be increased as compared with the conventional one.

  Further, since the track pad 32 is integrated with the variable pad 34, it is possible to satisfactorily prevent the track pad 32 and the variable pad 34 from being misaligned with each other during the insertion. Can be inserted and set.

  Furthermore, in the present embodiment, the front end portion and the rear end portion of the variable pad 34 protrude from the front and rear of the tie plate 16, and the protruding portion 66 is formed flexibly with respect to the track pad 32 to enter the variable pad 34. Since the protruding portions 66 are bulged downward by injecting the resin and the tie plate 16 is sandwiched from the front and rear, even if the rail 14 is displaced due to expansion and contraction, the variable pad It is possible to prevent 34 from being displaced forward and backward with respect to the tie plate 16 and to prevent such a variable pad 34 from being detached from the tie plate 16 in some cases.

Next, FIGS. 13 to 15 show another embodiment of the present invention.
In this embodiment, the variable pad 34 is configured as a single unit that is not integrated with the track pad 32.
Also in this embodiment, the stretchable part 50 is provided so as to stand upward along the peripheral edge of the variable pad 34.

However, in this embodiment, the expansion / contraction part 50 is comprised by the flexible film 50A, 50B, 50C, 50D of a total of 4 sheets mutually folded.
As shown in FIG. 13, in this embodiment, the inlet 62 and the exhaust port 64 are provided on the opposite sides of the tie plate 16 in the rail direction. Here, a check valve 70 is built in the inlet 62.

It is to be noted that the holding recess 51 of the track pad 32 is formed inside the expansion / contraction part 50 as in the above embodiment.
However, in this embodiment, the resin reservoir as described above is not provided in the variable pad 34. However, it is also possible to provide this.
The material of the variable pad 34 can be a polyamide film or other materials in addition to the rubber as described above.

FIG. 14 shows a state in which the variable pad 34 and the track pad 32 are combined in a state before the liquid resin is injected.
As shown in the figure, in this embodiment, in addition to the upper surface of the track pad 32, a plurality of grooves 36 extending in the front-rear direction, which is the rail direction, are formed at a predetermined pitch in the left-right direction. .
Reference numeral 72 denotes a sliding plate made of a SUS steel plate, which is integrally fixed to the upper surface of the track pad 32.

As shown in FIG. 14, the track pad 32 is received and held in a fitted state in a holding recess 51 formed on the inner side of the stretchable portion 50 of the variable pad 34.
In this embodiment, the variable pad 34 and the track pad 32 are described as separate members. Of course, the variable pad 34 and the track pad 32 are bonded and integrated on the upper and lower mating surfaces. Is also possible.

FIG. 15 shows a state in which a liquid resin is injected into the variable pad 34 and is expanded to increase the thickness.
As shown in the figure, also in this embodiment, the variable pad 34 is such that only the stretchable portion 50 extends in the vertical direction, that is, the flexible films 50A, 50B, 50C, 50D are flexibly deformed in the vertical direction. Thus, the thickness of the variable pad 34 itself does not change specially even when it is expanded by injecting a liquid resin.

  Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention may be configured such that the portion of the variable pad 34 excluding the stretchable portion 50 is made of hard resin, metal, or the like. For example, it can be configured in various forms without departing from the spirit thereof.

It is a figure which shows the variable track pad containing the variable pad which is one Embodiment of this invention in a construction completion state. It is a perspective view (partially cutaway view) showing the variable track pad. FIG. 3 is a plan view of the variable track pad of FIG. 2. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. It is a perspective view which decomposes | disassembles and shows the variable track pad of FIG. 2 to the track pad and the half which forms a part of variable pad. FIG. 7 is a plan view of a track pad and a half body shown in FIG. 6. It is explanatory drawing which shows the construction procedure of the variable track pad. It is explanatory drawing following FIG. It is explanatory drawing following FIG. It is the figure which showed the procedure of FIG.9 (III) in detail. It is the principal part enlarged view of FIG. 10 (V) (A). It is a figure of the variable pad of other embodiments of the present invention. It is a figure which shows the state which combined the variable pad and track pad of FIG. It is a figure which shows the state which injected resin to the variable pad of FIG. It is the figure which showed the conventional variable pad and the track pad with the peripheral part in the construction completion state. It is the figure shown with the peripheral part in the state before inflating the variable pad in FIG. FIG. 17 is a plan view of FIG. 16. It is a figure for demonstrating the construction procedure of the conventional variable pad and a track pad, and its problem.

Explanation of symbols

12 rail 16 tie plate 32 track pad 34 variable pad 50A, 50B, 50C, 50D flexible membrane 50 expansion / contraction part 51 holding recess 66 protrusion part

Claims (4)

It is inserted between the rail and a rail support such as a tie plate in the form of a bag together with a track pad made of an elastic plate and with the track pad facing upward, and in the inserted state, a liquid curable resin is inserted into the interior. In the variable pad to swell up and down by filling to fill the gap below the rail, and to hold the rail at the adjustment height by curing the injected resin,
A flexible film is folded along the peripheral edge, and the flexible film is elastically deformed in the vertical direction, and the vertical stretchable part orients the flexible film in the vertical direction. A variable pad, wherein the variable pad is provided in a standing state so as to overlap in a horizontal direction.   In Claim 1, the expansion-contraction part provided in the standing state along the said peripheral part forms the holding recess of the said track pad inside, and can make it possible to accommodate this track pad in this holding recess. This is a variable pad.   The variable pad according to claim 1, wherein the track pad is integrated.   In any one of Claims 1-3, while the front-end part and the rear-end part are made into the magnitude | size which protrudes ahead and back from this rail support body in the insertion state between the said rail and rail support body, at least those The front and rear protrusions are formed flexibly with respect to the track pad, and the front and rear protrusions bulge downward by the injection of the liquid resin and sandwich the rail support from the front and rear. A variable pad characterized by the above.

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