Abstract:
A pre-buried casing tube uses glass fiber reinforced resin as the raw material to enhance the operation strength of the pre-buried casing tube, extend the service life of the pre-buried casing tube, and reduce maintenance cost of the railway transport system. The pre-buried casing tube includes at least one casing tube body, each casing tube body including at least one retaining element, the retaining elements provided in intervals along one side of the casing tube, each casing tube body disposed adjacently so as to form a passage for a screw, each retaining element provided in the passage for the screw.

Description:
CROSS REFERENCE OF RELATED APPLICATION 
       [0001]    This is a non-provisional application that claims priority to International Application Number PCT/CN/2015/158303, filed Apr. 17, 2015, which claims priority under 35 U.S.C. 119(a-d) to Chinese application number 201410036845.6, filed Apr. 17, 2014. 
     
    
     NOTICE OF COPYRIGHT 
       [0002]    A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
       BACKGROUND OF THE PRESENT INVENTION 
       [0003]    Field of Invention 
         [0004]    The present invention relates to a casing tube and manufacturing method thereof, and particularly to a pre-buried casing tube to fasten the rails with the sleeper during laying the railway transportation system, wherein the casing tube is made of fiberglass reinforced resin composite which is internally dispersed evenly and stable in structure as to enforce strength of the casing tube for satisfying requirements of the casing tube in railway transportation system. 
         [0005]    Description of Related Arts 
         [0006]    The railway transportation system, especially for a wheeled vehicle running on rails, is an overland transportation to transport passengers or goods. The development of the railway transportation plays an important part in the stability and sustainable development of the modern society. 
         [0007]    The railway transportation, represented by new transportation mode such as high-speed rail, subway and express rail line, is a powerful transportation tool and can effectively improve the unbalanced distribution of physical resources and human resources geographically and make the distance of people closer. Therefore, the recent railway transportation system are rapidly improved with worldwide popularity. 
         [0008]    The entire railway transportation system, which is a unified whole system, comprises at least a preset railroad and wheeled vehicles running on the railroad. In other words, the railroad is a necessary component of the railway transportation system. 
         [0009]    The railroad comprises a plurality of interlinked rails and a plurality of sleepers, wherein the rails are anchored to the sleepers which are provided on the rail-bed at regular intervals, wherein one function of the rail-bed is to support the sleepers and transmit the huge load from the upward of the sleepers to the foundation so as to reduce deformation of the foundation for the sustainability of the railway transportation system. After the rails lay on the sleepers, the major problem is to fasten rails on sleepers stably and reliably. Traditionally, as the sleeper has been molded integrally, a pre-embedded casing tube  10 P is placed at the preset position (as shown in  FIG. 1 ) for securely fasten the pre-embedded casing tube  10 P in the sleeper. Then by means of screwing, the rail is fastened on the sleeper. 
         [0010]    As shown in  FIG. 1 , the traditional pre-embedded casing tube  10 P is made of “nylon 66” integrally. Specifically, the pre-embedded casing tube  10 P has a screw channel  11 P, wherein the inner surface of pre-embedded casing tube  10 P forms a thread portion to define the screw channel  11 P for fastening the rail on the sleeper by a screw. The outer surface of pre-embedded casing tube  10 P further comprises a preset thread portion. As the sleeper being molded, the pre-embedded casing tube  10 P is provided on the preset position, and is molded with the sleeper integrally to fasten the pre-embedded casing tube  10 P in the sleeper stably. However, as the sleeper has been molded, the pre-embedded casing tube  10 P is fastened to the sleeper linearly. In actual situation, because of sustained mechanical vibrations from the vehicle to the preset rail, it is easy for the pre-embedded casing tube  10 P rotated at the clockwise and the counter-clockwise directions along the outer surface of the pre-embedded casing tube  10 P and even dropped from the sleeper. These cause serious damages to operation security of the railway transportation system. 
         [0011]    Moreover, the pre-embedded casing tube  10 P is made of nylon 66. But the strength of nylon 66 is hard to resist the stress generated from sustained mechanical vibrations from the vehicle to the preset railroad for the pre-embedded casing tube  10 P. It is relatively easy to shear one set of thread portion in the inner surface of the pre-embedded casing tube  10 P by the screw after a period of continuous use. This reason will accelerate the aging of the tradition pre-embedded casing tube  10 P. Therefore, the accelerated aging of the pre-embedded casing tube  10 P leads to two problems directly. The first problem is the high cost for maintenance of preset railroad. The second problem is the uncertainty of sustainability and security in the railway transportation system. 
         [0012]    Otherwise, because of physical properties of nylon 66, there are further three problems of the pre-embedded casing tube  10 P. 
         [0013]    In relative moist environment, the pre-embedded casing tube  10 P will have certain strength after oxidation. However, in actual application, the environment of the pre-embedded casing tube  10 P in different locations or environments will have different strengths. In an elevated location, such as Tibet Plateau, the humidity is relatively low that the pre-embedded casing tube  10 P is too fragile to resist the stress from sustained mechanical vibrations from the vehicle to the preset railroad. It is easy to damage even using the pre-embedded casing tube  10 P in enforced nylon 66. This is the reason of high cost, great difficulty and accelerated damaging of the pre-embedded casing tube  10 P in the elevated locations compared to the humid region for laying preset railroads. Also, the corrosion resistance and abrasive resistance of nylon 66 are not good enough which strongly limits application of the pre-embedded casing tube  10 P and effects the lifetime of the pre-embedded casing tube  10 P negatively. 
         [0014]    On the other hand, nylon 66 is easy to be thermal-degraded. As vehicles running on the preset railroad at high speed, the railroad is getting hotter because of the friction of vehicles and railroads. With the increasing temperature of railroad, the environmental temperature of the pre-embedded casing tube  10 P will be higher. Under such high environmental temperature for a long period of time, the nylon 66 made pre-embedded casing tube  10 P will be thermal-degraded. The thermal degradation mainly shows as cracking of main chain which leads to reduction of molecular weight and melt viscosity. In further degradation, the three-dimensional structure of nylon 66 causes the increase of melt viscosity to be a gel form, and eventually to be insoluble and infusible matter. Therefore, this is a main reason why the durability of the traditional pre-embedded casing tube  10 P is low. 
         [0015]    Furthermore, as the pre-embedded casing tube  10 P is in the humid environment for a long period of time, the insulation ability of the pre-embedded casing tube  10 P will be lower and even normal signal transmission will be damaged which is a potential danger to security. 
       SUMMARY OF THE PRESENT INVENTION 
       [0016]    The invention is advantageous in that it provides a casing tube and manufacturing method thereof, wherein the pre-buried casing tube is made of fiberglass reinforced resin composite which is dispersed evenly internally and stable in structure as to enforce strength of the casing tube for satisfying the needs of the casing tube in railway transportation system. 
         [0017]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein molecules of the fiberglass reinforced resin composite forms reticulate cubic structure so that the casing tube is has higher strength and specific modulus to enforce the consistency and concordance of internal structure of the casing tube made by the fiberglass reinforced resin composite. 
         [0018]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein when the casing tube is used, especially under an extreme environment, the casing tube will not block the signal transmission to ensure the continuity of signal transmission for the security of railway running. 
         [0019]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein the casing tube has at least one locating element. As the casing tube is fastened at the preset position, the material to make sleeper will be flowed and permeated to solidify into a locating slot formed by every two of the adjacent locating elements so that sleeper and the casing tube is meshed with each other. In this way, it can increase the mash force between sleeper and the casing tube to ensure the reliability when using the casing tube. 
         [0020]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein each of the locating element is spacedly provided on outer surface of the casing tube, whereby the vertical force relationship is formed between the casing tube and the sleeper so that the mesh force between each of the locating element of the outer surface of the casing tube and the sleeper is larger. 
         [0021]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein the casing tube can be pre-embedded in the sleeper alone to improve the efficiency of laying railway system. 
         [0022]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein while laying the railway system, the screw can be pre-embedded in the sleeper, then rail is fastened to the sleeper by the casing tube to form railway system. 
         [0023]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein each of the tube bodies comprises a first body and a second body, wherein the first body is made of the fiberglass reinforced resin composite formed by long fiberglass and resin mixed with each other, wherein the second body is made of the fiberglass reinforced resin composite formed by short fiberglass and resin mixed with each other. The inner surface and outer surface of the casing tube is formed by the first body and the second body respectively for bearing different characters of force by inner portion and outer portion of the casing tube. 
         [0024]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein each of the tube bodies of the casing tube comprises a holding member and a holding slot, wherein as the tube bodies are coupled with each other, the holding member can be held in the holding slot, so that when the casing tube bears transverse impact force, the casing tubes will not be malpositioned to increase the reliably thereof. 
         [0025]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein each of the tube bodies of the casing tube comprises a holding member and a holding slot, wherein as the tube bodies are coupled with each other, the holding member can be held in the holding slot, so that the connection between the tube bodies is effectively sealed, whereby the material formed the sleeper won&#39;t be permeated into the casing tube through the connection of the tube bodies as pre-embedding the casing tube in the sleeper. 
         [0026]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein each side portion of the casing tube comprises a set of locating tooth, as the tube bodies are coupled with each other, the locating teeth of the tube bodies are meshed with each other, so that the adjacent casing tubes will not be malpositioned between the tube bodies when the casing tube bears sustained up and down vibrations. 
         [0027]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein the casing tube made by the fiberglass reinforced resin composite has lower cost. 
         [0028]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein the casing tube is hard to damage which reduces maintenance cost for railway transformation system. 
         [0029]    Another advantage of the invention is to provide a casing tube and manufacturing method thereof, wherein the casing tube is simple in structure and durable in aging without complex manufacturing process and expensive material. With lower manufacturing cost, the casing tube has a promising market. 
         [0030]    Additional advantages and features of the invention will become apparent from the description which follows, and may be realized by means of the instrumentalities and combinations particular point out in the appended claims. 
         [0031]    According to the present invention, the foregoing and other objects and advantages are attained by a casing tube for engaging with a screw, comprising: 
         [0032]    at least two tube bodies, each of the tube bodies having an inner-side surface and at least one retaining element provided on the inner-side surface, wherein when the tube bodies are coupled with each other, the inner-side surfaces of the tube bodies define a screw channel therebetween to receive the screw therein, wherein the retaining element of each of the tube bodies is provided for engaging with the screw. 
         [0033]    According to the embodiments of the present invention, the retaining element of each of the tube bodies defines a thread portion adapted to engage with the screw. 
         [0034]    According to the embodiments of the present invention, each of the tube bodies has an outer-side surface and at least one locating element provided on the outer-side surface. 
         [0035]    According to the embodiments of the present invention, the casing tube further comprising at least one fastening unit, which each of the fastening units is provided on the outer-side surface of the tube body to provide a binding force for the tube body. 
         [0036]    According to the embodiments of the present invention, the fastening units are spacedly encircled around the outer surfaces of the tube bodies. 
         [0037]    According to the embodiments of the present invention, each of the tube bodies has a first side portion and a second side portion, wherein the first side portion and the second side portion are respectively and radially extended from the tube body and the first side portion and the second side portion of the tube bodies are coupled with each other. 
         [0038]    According to the embodiments of the present invention, the casing tube further comprises at least one binding layer, wherein the binding layer is provided between the first side portion and the second side portion of the tube bodies for connecting the two tube bodies with each other by the binding layer. 
         [0039]    According to the embodiments of the present invention, the distance between the inner-side surface and the outer-side surface is smaller than the thickness of the first side portion and the second side portion. 
         [0040]    According to the embodiments of the present invention, the casing tube has two tube bodies, which are symmetric with each other so as to define the screw channel between the inner-side surfaces of the two tube bodies, wherein the tube body further has a holding member provided at the first side portion and a holding slot provided in the second side portion, wherein when the two tube bodies are coupled with each other, the holding member is engaged with the holding slot. 
         [0041]    According to the embodiments of the present invention, one tube body has two holding members provided respectively at the first side portion and the second side portion thereof, and another tube body has two holding slots provided respectively in the first side portion and the second side portion thereof such that when the tube bodies are coupled with each other, the holding members are engaged with the holding slots respectively. 
         [0042]    According to the embodiments of the present invention, each of the tube bodies comprises a first body and a second body, wherein the first body and the second body are overlapped with each other to form the tube body, wherein the retaining element is defined by the second body, and the locating element is defined by the first body. 
         [0043]    According to the embodiments of the present invention, the first body is made of long fiberglass and resin mixed with each other, and the second body is made of short fiberglass and resin mixed with each other. 
         [0044]    According to the embodiments of the present invention, each of the fastening units has a strip shape and made of fiberglass and resin mixed with each other. 
         [0045]    According to the embodiments of the present invention, each of the fastening unit has a ring shape, and is made of elastic material, so that at the normal state of the fastening unit, which is not stretched by any force, the diameter of the fastening unit is smaller than the diameter of the casing tube, and when the fastening unit is encircled around the casing tube, the fastening unit provides a binding force around the casing tube. 
         [0046]    According to the present invention, the foregoing and other objects and advantages are attained by a casing tube, comprising: 
         [0047]    a tube body, wherein the tube body has an inner-side surface and an outer-side surface corresponding to the inner-side surface, wherein the inner-side surface of the tube body defines a screw channel and a thread portion, wherein the screw channel is provided to receive a screw therein, and the thread portion is provided for screwing the screw, wherein the tube body has at least one locating element provided on the inner-side surface for locating a sleeper thereat. 
         [0048]    According to the embodiments of the present invention, the locating elements are spacedly provided on the outer-side surface of the tube body, such that every two of the adjacent locating elements define a locating slot therebetween to allow a fluid for defining the sleeper to flow through the locating slot and be held in the locating slot. 
         [0049]    According to the embodiments of the present invention, the locating element is curvedly extended from one end of the casing tube to another end of the casing tube. 
         [0050]    According to the embodiments of the present invention, the tube body is made of fiberglass and resin mixed with each other. 
         [0051]    In accordance with another aspect of the invention, the present invention comprises a casing tube which is made by a fiberglass reinforced resin composite material, comprising: 
         [0052]    at least one fiberglass selected from the group consisting of alkali-free fiberglass, medium-alkali fiberglass and the combination thereof; and 
         [0053]    at least one resin selected from the group consisting of o-phthalate unsaturated polyester resins, m-phthalate unsaturated polyester resins, bisphenol-A type unsaturated polyester resin, terephthalic unsaturated polyester resin, vinyl ester resin, epoxy resin, phenolic resin bisphenol-a type epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, diglycidyl ester type resins, glycidylamine type epoxy resin, epoxidations of alkenes compounds, heterocyclic epoxy resin, mixed epoxy resin and the combination thereof, wherein the content of the resin is 30%-40%, wherein the content of the fiberglass is 60%-70%, wherein the fiberglass and the resin are mixed and heated to composite the fiberglass and the resin so as to form the fiberglass reinforced resin composite material. 
         [0054]    According to the embodiments of the present invention, the content of the fiberglass is 67%, and the content of the resin is 33%. 
         [0055]    In accordance with another aspect of the invention, the present invention comprises a method for manufacturing a casing tube, comprising the steps of: 
         [0056]    (a) mixing the fiberglass and the resin to get a mixture of the fiberglass and the resin; 
         [0057]    (b) pressing the mixture to composite and mold the mixture to obtain a tube body, wherein the tube body has at least a retaining element; and 
         [0058]    (c) coupling at least two the tube bodies with each other to define a screw channel therebetween, wherein the retaining element is located in the screw channel to define the casing tube. 
         [0059]    According to the embodiments of the present invention, the method further comprising a step of: 
         [0060]    (d) proving at least a fastening unit on the outer surface of the casing tube to fasten the tube bodies. 
         [0061]    According to the embodiments of the present invention, the method further comprising a step of: 
         [0062]    (e) providing a binding layer between the neighboring tube bodies for connecting the tube bodies with each other. 
         [0063]    According to the embodiments of the present invention, in the step (d), binding the mixture having a strip shape on the outer surface of the casing tube so as to make the mixture form the fastening unit. 
         [0064]    According to the embodiments of the present invention, in the step (b), each of the tube bodies defines at least one locating element on the outer surface thereof. 
         [0065]    According to the embodiments of the present invention, in the step (b), overlapping the mixture made of long fiberglass and resin and the mixture of short fiberglass and resin with each other to make the mixture of long fiberglass and resin define the locating element and make the mixture of short fiberglass and resin define the retaining element. 
         [0066]    According to the embodiments of the present invention, in the step (d), soaking the fiberglass in the resin to permeate the resin into the gaps of the fiberglass bunch, so as to form the fastening unit. 
         [0067]    According to the embodiments of the present invention, in the step (d), making the resin flow through the fiberglass bunch to permeate the resin into the gaps of fiberglass bunch to form the fastening unit. 
         [0068]    In accordance with another aspect of the invention, the present invention comprises a method for manufacturing a casing tube by a fiberglass reinforced resin composite material, comprising the steps of: 
         [0069]    (1) preparing the fiberglass reinforced resin composite material; 
         [0070]    (2) making the fiberglass reinforced resin composite material be in a sol state; and 
         [0071]    (3) gelling the fiberglass reinforced resin composite material via the casing tube module and demolding to obtain the casing tube, wherein the casing tube has a screw channel and a thread portion provided in the screw channel. 
         [0072]    According to the embodiments of the present invention, before the step (1), the method further comprising the steps of: 
         [0073]    (1.1) mixing the fiberglass and resin to obtain a mixture of the fiberglass and resin; and 
         [0074]    (1.2) heating and/or pressing the mixture of the fiberglass and resin to composite the fiberglass and resin and form the fiberglass reinforced resin composite material in sol state. 
         [0075]    According to the embodiments of the present invention, the step (1.2) further comprises the steps of: 
         [0076]    (1.2.1) forming the fiberglass reinforced resin composite material in sol state by long fiberglass reinforced resin; 
         [0077]    (1.2.2) forming the fiberglass reinforced resin composite material in sol state by short fiberglass reinforced resin; and 
         [0078]    (1.2.3) overlapping the two fiberglass reinforced resin composite materials in the step (1.2.1) and the step (1.2.2). 
         [0079]    According to the embodiments of the present invention, the fiberglass reinforced resin composite material further comprises: 
         [0080]    at least one resin selected from the group consisting of o-phthalate unsaturated polyester resins, m-phthalate unsaturated polyester resins, bisphenol-A type unsaturated polyester resin, terephthalic unsaturated polyester resin, vinyl ester resin, epoxy resin, phenolic resin bisphenol-a type epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, diglycidyl ester type resins, glycidylamine type epoxy resin, epoxidations of alkenes compounds, heterocyclic epoxy resin, mixed epoxy resin and the combination thereof, wherein the content of the resin is 30%-40%, wherein the content of the fiberglass is 60%-70%, wherein the fiberglass and the resin are mixed and heated to composite the fiberglass and the resin so as to form the fiberglass reinforced resin composite material. 
         [0081]    In accordance with another aspect of the invention, the present invention comprises a method for manufacturing a casing tube, comprising the steps of: 
         [0082]    (I) providing at least two tube bodies, wherein each of the tube bodies has a curved inner-side surface and at least a retaining element provided on the inner-side surface; and 
         [0083]    (II) coupling the tube bodies with each other to define a screw channel between the inner-side surfaces of the tube bodies to obtain the casing tube, wherein each of the retaining elements is provided in the screw channel. 
         [0084]    According to the embodiments of the present invention, the method further comprises a step of: 
         [0085]    (III) binding at least one fastening unit on the casing tube, wherein the fastening unit is provided for fastening each of the tube bodies. 
         [0086]    According to the embodiments of the present invention, the step (III) further comprises a step of soaking the fiberglass in the resin to permeate the resin into the gaps of the fiberglass bunch, so as to form the fastening unit 
         [0087]    According to the embodiments of the present invention, the step (III) further comprises a step of making the resin flow through the fiberglass bunch to permeate the resin into the gaps of fiberglass bunch to form the fastening unit. 
         [0088]    In accordance with another aspect of the invention, the present invention comprises a method for manufacturing a casing tube, comprising the steps of: 
         [0089]    (A) preparing a billet for the tube body, wherein the size of the billet is no less than the size of tube body; 
         [0090]    (B) cutting the billet to obtain the tube body, wherein the tube body has a curved inner-side surface and at least one retaining element provided on the inner-side surface; and 
         [0091]    (C) coupling at least two tube bodies to define a screw channel between the inner-side surfaces of the tube bodies to obtain the casing tube, wherein each of the retaining elements is provided in the screw channel. 
         [0092]    According to the embodiments of the present invention, the step (A) further comprises the steps of: 
         [0093]    (A.1) putting the unmolded material in the mould for the billet of the tube body; and 
         [0094]    (A.2) heating and/or pressing the unmolded material via the mould for the billet of the tube body to obtain the billet. 
         [0095]    According to the embodiments of the present invention, the method further comprising a step of: 
         [0096]    (D) binding at least one fastening unit on the tube body, wherein the fastening unit is adapted for fastening each of the tube bodies. 
         [0097]    According to the embodiments of the present invention, the method further comprising a step of: 
         [0098]    (E) arranging a binding layer between the neighboring tube bodies for connecting the neighboring tube bodies with each other. 
         [0099]    In accordance with another aspect of the invention, the present invention comprises a method for manufacturing a casing tube, comprising the steps of: 
         [0100]    Step 1: preparing a mixture of fiberglass and resin, wherein the mixture has a strip shape; 
         [0101]    Step 2: binding the mixture on a mould core to obtain a billet for the casing tube; 
         [0102]    Step 3: mould pressing the billet to fasten and mold the billet; and 
         [0103]    Step 4: demolding, and removing the mould core to obtain the casing tube. 
         [0104]    According to the embodiments of the present invention, the step 1 further comprises the steps of: 
         [0105]    Step 1.1: mixing the fiberglass and the resin to prepare the mixture; and 
         [0106]    Step 1.2: bunching the mixture to make the mixture have a bunch shape. 
         [0107]    According to the embodiments of the present invention, the Step 1 further comprises the steps of: 
         [0108]    Step 1.3: making the fiberglass have a bunch shape; and 
         [0109]    Step 1.4: making the resin permeate into the gaps of the fiberglass to form the mixture having a strip shape. 
         [0110]    According to the embodiments of the present invention, wherein the step 1.4 further comprises the steps of: 
         [0111]    Step 1.4.1: soaking the fiberglass in the resin; and 
         [0112]    Step 1.4.2: making the resin permeate into the gaps of the fiberglass bunches. 
         [0113]    According to the embodiments of the present invention, the Step 1.4 further comprises the steps of: 
         [0114]    Step 1.4.1: making the resin flow through the fiberglass having a bunch shape; and 
         [0115]    Step 1.4.2: making the resin permeate into the gaps of the fiberglass bunch. 
         [0116]    According to the embodiments of the present invention, the step 2 further comprises a step of: 
         [0117]    rotating the strip-shaped mixture of fiberglass and resin around the mould core to bind the mixture on the mould core. 
         [0118]    According to the embodiments of the present invention, the step 2 further comprises a step of: 
         [0119]    driving the mould core to rotate to bind the mixture of fiberglass and resin on the mould core. 
         [0120]    According to the embodiments of the present invention, the method further comprises the following step before the step 2: 
         [0121]    coating a releasing agent layer on the mould core. 
         [0122]    According to the embodiments of the present invention, a distal end of the mould core has a size smaller than a near-end thereof. 
         [0123]    According to the embodiments of the present invention, a distal end of the mould core has a size smaller than a near-end thereof. 
         [0124]    Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings. 
         [0125]    These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0126]      FIG. 1  is a perspective view of traditional pre-embedded casing tube. 
           [0127]      FIG. 2  is an exploded perspective view of a casing tube used in a railroad according to a preferred embodiment of the present invention. 
           [0128]      FIG. 3  is a sectional view of the casing tube used in the railroad according to a preferred embodiment of the present invention. 
           [0129]      FIG. 4  is a perspective view of the casing tube according to a preferred embodiment of the present invention. 
           [0130]      FIG. 5  is an exploded perspective view of the casing tube according to a preferred embodiment of the present invention. 
           [0131]      FIG. 6  is a sectional view of the casing tube according to the preferred embodiment of the present invention. 
           [0132]      FIG. 7  is a sectional view of the casing tube according to the preferred embodiment of the present invention, illustrating the binding layer. 
           [0133]      FIG. 8  illustrates an alternative mode of the casing tube according to the preferred embodiment of the present invention. 
           [0134]      FIG. 9  is a perspective view illustrating the alternative mode of the casing tube according to the preferred embodiment of the present invention. 
           [0135]      FIG. 10  is a sectional view of each tube body of the casing tube according to the preferred embodiment of the present invention. 
           [0136]      FIGS. 11A and 11B  are diagrams illustrating the distribution of the fiberglass reinforced resin composite of the casing tube according to the preferred embodiment of the present invention. 
           [0137]      FIG. 12  is a force analysis diagram of the fiberglass reinforced resin composite of the casing tube according to the preferred embodiment of the present invention. 
           [0138]      FIG. 13  is a perspective view of a casing tube according to a second preferred embodiment of the present invention. 
           [0139]      FIG. 14  is an exploded perspective view of the casing tube according to the second embodiment of the present invention. 
           [0140]      FIG. 15  illustrates an alternative mode of the casing tube according to the second embodiment of the present invention. 
           [0141]      FIG. 16  a perspective view of a casing tube according to a third preferred embodiment of the present invention. 
           [0142]      FIG. 17  is a sectional view of the casing tube according to the third preferred embodiment of the present invention. 
           [0143]      FIG. 18  illustrates an alternative mode of the casing tube according to the third preferred embodiment of the present invention. 
           [0144]      FIGS. 19A to 19E  are manufacturing process diagrams of the casing tube according to above preferred embodiments of the present invention. 
           [0145]      FIG. 20  is a block diagram illustrating the manufacturing process of the casing tube according to above preferred embodiments of the present invention. 
           [0146]      FIG. 21  is a block diagram illustrating the manufacturing method of the casing tube according to above preferred embodiments of the present invention. 
           [0147]      FIG. 22  is a block diagram illustrating a first alternative mode of the manufacturing method of the casing tube according to above preferred embodiments of the present invention. 
           [0148]      FIG. 23  is a block diagram illustrating a second alternative mode of the manufacturing method of the casing tube according to above preferred embodiments of the present invention. 
           [0149]      FIG. 24  is a block diagram illustrating a third alternative mode of the manufacturing method of the casing tube according to above preferred embodiments of the present invention. 
           [0150]      FIG. 25  is a sectional view of the casing tube used in the railroad according to a fourth preferred embodiment of the present invention. 
           [0151]      FIG. 26  is a perspective view of the casing tube according to the fourth preferred embodiment of the present invention. 
           [0152]      FIG. 27  is an exploded perspective view of the casing tube according to the fourth preferred embodiment of the present invention. 
           [0153]      FIG. 28  is a sectional view of the casing tube according to the fourth preferred embodiment of the present invention. 
           [0154]      FIG. 29  illustrates an alternative mode of the casing tube according to the fourth preferred embodiment of the present invention. 
           [0155]      FIG. 30  is an exploded perspective view illustrating the alternative mode of the casing tube according to the fourth preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0156]    The following description is disclosed to enable any person skilled in the art to make and use the present invention. Preferred embodiments are provided in the following description only as examples and modifications will be apparent to those skilled in the art. The general principles defined in the following description would be applied to other embodiments, alternatives, modifications, equivalents, and applications without departing from the spirit and scope of the present invention. 
         [0157]    As shown in  FIG. 2  to  FIG. 10 , a casing tube  10  according to a preferred embodiment of the present invention is disclosed and described in detail as following, wherein the casing tube  10  as a pre-buried casing tube is applied in railway transformation system, to fasten a rail  30  on a sleeper  40  by a screw  20  for the rail  30  maintaining a stable structural connection with the sleeper  40 . 
         [0158]    Specifically, in the preferred embodiment of the present invention, each of the casing tubes  10  can be pre-embedded in the sleeper  40 . Therefore, after the rail  30  is provided on the surface of the sleeper  40 , the screw  20  can lock the rail  30  to the sleeper  40  from up to bottom. 
         [0159]    More specifically, the casing tube  10  comprises at least two tube bodies  11  each having an arc-shape, preferably identical with each other, wherein each of the tube bodies  11  has an inner-side surface  130  and an outer-side surface  140  corresponding to the inner-side surface  130 . The tube body  11  has at least one retaining element  111  integrally formed on the inner-side surface  130 . As the tube bodies  11  are fittingly coupled with each other to form the casing tube  10 , the inner-side surfaces  130  of the tube bodies  11  form a screw channel  12  as a passage for holding and engaging with the screw  20 . And the retaining elements  111  of the tube bodies  11  are correspondingly matched with each other to form a thread portion  121  for the screw  20  screwing thereat. 
         [0160]    As in  FIG. 3  of the preferred embodiment of the present invention, the casing tube  10  has two tube bodies  11 . Especially, the two tube bodies  11  can be overlappedly coupled with each other edge-to-edge that the inner-side surface  130  of the two tube bodies  11  form the screw channel  12  and the thread portion  121  by the retaining elements  111 . The casing tube  10  further comprises one or more fastening units  13 , wherein when each of the tube bodies  11  fittingly coupled with each other, the fastening units  13  are spacedly and coaxially encircled around the outer surface of the casing tube  10  so as to fasten the tube bodies  11  together. So, the screw  20  is not only effectively sealed the gap of contact between the tube bodies  11 , but also prevented mis-displacement of the tube bodies  11  under stress by each of the fastening unit  13  when the casing tube  10  bears a transverse impact force to ensure stability of structure of the casing tube  10 . It is understandable for one skilled in the art, the sleeper  40  is usually made of material like the ferroconcrete in which the fluidity thereof is high before solidification. As the casing tube  10  is provided at the preset position, and the sleeper  40  is molded by a molding process, the flow of material made the sleeper  40  will generate transverse impact force to the casing tube  10  to make the one of tube bodies  11  tend to be mis-displaced. Then each of the fastening unit  13  prevents the tube body  11  to be mis-displacement. Therefore, the material made the sleeper  40  will not be permeated into the screw channel  12  through the gap of contact between the neighboring tube bodies  11 . Also the thread portion  121  inside the screw channel  12  formed by the casing tube  10  will not be malpositioned. 
         [0161]    The outer-side surface  140  of each of the tube bodies  11  of the casing tube  10  has at least one locating element  14  formed in an annular shape. In other words, each of the locating elements  14  is integrally and coaxially protruded from the outer-side surface  140  of the tube body  11 , so that after the casing tube  10  is fastened on the sleeper  40 , each of the locating elements  14 , which serves as a reinforcing rim, is enforced the meshing force between the outer surface of the casing tube  10  with the sleeper  40 . Specifically, every two of the adjacent locating elements  14  form a locating slot  141  therebetween, wherein as the casing tube  10  is fastened at the preset position of the sleeper  40 , the material made the sleeper  40  will flow to permeate in the locating slot  141  between the adjacent locating elements  14 . Therefore, after the sleeper  40  is molded, the sleeper  40  is meshed with the outer surface of casing tube  10 . In this way, each of the locating elements  14  is enforced the meshing force between the outer surface of the casing tube  10  with the sleeper  40  to make the connection between the casing tube  10  and the sleeper  40  more stable. 
         [0162]    Comparing with the thread structure of traditional pre-embedded casing tube  10 P (in  FIG. 1 ), because each of the locating elements  14  of the present invention is set along the outer surface of the casing tube  10  separately, after the sleeper  40  is molded, each of the locating elements  14  forms vertical force relationship with the sleeper  40 . Specifically, when the vehicle runs on the rail  30 , the vehicle generates sustained mechanical vibrations to the sleeper  40 . This mechanical vibrations directly leads to make the casing tube  10  tend to move up and down against the sleeper  40 . But because of each of the locating elements  14  and each of the locating slots  141  the casing tube  10  will not move against the sleeper  40 . So, the casing tube  10  and the sleeper  40  have formed stable position relationship. The thread structure of traditional pre-embedded casing tube  10 P has a set of thread portion. When the pre-embedded casing tube  10 P bears sustained mechanical vibrations from the vehicle to the sleeper  40 , the negative result is the pre-embedded casing tube  10 P rotated positively or reversely which changes the relationship between the pre-embedded casing tube  10 P and the sleeper  40  and results in decreasing durability. 
         [0163]    Each of the tube bodies  11  has a first side portion  110  and a second side portion  120  extended radially, wherein the first side portion  110  and the second side portion  120  are extended from edges of each of the tube bodies  11  respectively. As each of the tube bodies  11  is provided fittingly to form the casing tube  10 , the first side portion  110  and the second side portion  120  of the tube bodies  11  are overlapped coupled with each other. And the first side portion  110  and the second side portion  120  of the each tube body  11  can prevent each of the tube bodies  11  rotating against each other. It is worth mentioning that two ends of the locating element  14  are extended from the first side portions  110  of one tube body  11  and two ends of the locating elements  14  are extended from the second side portions  120  of another tube body  11 . 
         [0164]    Specifically, the first side portion  110  and the second side portion  120  of each of the tube bodies  11  are extended from the inner-side surface  130  to the outer-side surface  140  respectively, and the first side portion  110  and the second side portion  120  of the tube bodies  11  are protruded from the outer-side surfaces  140  of the tube bodies  11 . In other words, the first side portion  110  has a slot and the second side portion  120  has a protrusion to engage with the slot when the first side portion  110  and the second side portion  120  are coupled with each other. In this way, the contact between the first side portion  110  and the second side portion  120  of the tube bodies  11  can be increased to reduce the gap between the first side portion  110  and the second side portion  120  of the tube bodies  11  for ensuring the sealing between the tube bodies  11  of the casing tube  10 . 
         [0165]      FIG. 7  illustrates an alternative mode of the preferred embodiment above according to the present invention, wherein the casing tube  10  further comprises at least one binding layer  15  sandwiched between the first side portion  110  and the second side portion  120  of the tube bodies  11  when the tube bodies  11  are coupled with each other. And the binding layer  15  can further seal the gap between the first side portion  110  and the second side portion  120  of the tube bodies  11 . Thus the sealing between the first side portion  110  and the second side portion  120  of the casing tube  10  will be better. 
         [0166]      FIG. 8  and  FIG. 9  illustrate another alternative mode of the preferred embodiment above according to the present invention, the first side portion  110  and the second side portion  120  of the tube bodies  11  have a plurality of locating teeth  1120  respectively. As the first side portion  110  and the second side portion  120  of the tube bodies  11  are coupled with each other, the locating teeth  1120  are meshed with each other to prevent the vertical movement between the tube bodies  11 . 
         [0167]    The fastening unit  13  is in strip shape for binding the fastening unit  13  around the casing tube  10  so as to fasten the tube bodies  11  together. It is worth mentioning that the fastening unit  13  is made by fiberglass strands soaked in resin. 
         [0168]    Also, the fastening unit  13  can be configured to have a ring shaped element with a predetermined elasticity, such as an elastic ring. At the normal state of the fastening unit  13 , which is not stretched by any force, the diameter of the fastening unit  13  is smaller than the diameter of the casing tube  10 . So after the fastening unit  13  is encircled around the casing tube  10 , the elastic binding force of the fastening unit  13  is applied to the casing tube  10  to fasten the tube bodies  11  together. 
         [0169]    Before the use of the casing tube  10 , the casing tube  10  is preset in the sleeper  40  when the sleeper  40  is molded during the molding process. As the rail  30  is provided on the preset position of the sleeper  40 , the screw  20  is fastened from up to bottom, such that the thread portion  121  of the casing tube  10  and the screw  20  are fastened with other. 
         [0170]    As in  FIGS. 11A to 12 , modifications, such as other characters of the fiberglass reinforced resin composite of the present invention, are set forth and disclosed in details as following. 
         [0171]    Specifically, the fiberglass reinforced resin composite is constructed with at least one kind of fiberglass  50  and at least one kind of resin  60 . The fiberglass  50  is selected from the group consisting of alkali-free fiberglass, medium-alkali fiberglass and the combination thereof. The resin  60  is selected from the group consisting of o-phthalate unsaturated polyester resins, m-phthalate unsaturated polyester resins, bisphenol-A type unsaturated polyester resin, terephthalic unsaturated polyester resin, vinyl ester resin, epoxy resin, phenolic resin bisphenol-a type epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, diglycidyl ester type resins, glycidylamine type epoxy resin, epoxidations of alkenes compounds, heterocyclic epoxy resin, mixed epoxy resin and the combination thereof. The content of the resin  60  is 30%-40% by weight, and the content of the fiberglass  50  is 60%-70% by weight. The fiberglass  50  and the resin  60  are composited by heating the mixture of the fiberglass  50  and the resin  60 , then, forming the fiberglass reinforced resin composite. To be clear, when using the fiberglass  50  to modify the resin  60 , the molecules of the fiberglass  50  and the resin  60  forms reticulate cubic structure to enforce the consistency and concordance of internal structure of the fiberglass reinforced resin composite. Thus, the casing tube  10  has strength and rigidity of the fiberglass  50 , and lightweight and tenacity of the resin  60 , also, stability and durability for the casing tube  10  made by the fiberglass reinforced resin composite. 
         [0172]    Preferably, the content of the fiberglass  50  is 67% by weight, and the content of the resin  60  is 33% by weight. 
         [0173]    The principle of the fiberglass reinforced resin composite made the casing tube  10  is composited between the fiberglass  50  and the resin  60 . In details, the high strength of the fiberglass  50  can bear sustainable and frequent impact from trains to the rail which has negative effects to the casing tube  10 . The negative effects to the casing tube  10  are eliminated by the plastic flow of the resin  60  and the cohesiveness between the fiberglass  50  and the resin  60 . 
         [0174]    Furthermore, in longtime using of the casing tube  10 , if the negative effects of sustainable and frequent impact from trains to the rails cannot be overcome, inside the casing tube  10 , the fiberglass  50  is the first to fracture. It can be understood that, without the fiberglass  50  or near the fracture portion of the fiberglass  50 , the resin  60  is not going to bear the negative effect. But as the fracture portion of the fiberglass  50  is blocked by the plastic flow of the resin  60  adhered to the fracture portion of fiberglass  50 , the fiberglass  50  tend to fracture continually is stopped. Thus, somewhere far away from the fracture portion of fiberglass  50  still has enough strength to bear the negative effect. 
         [0175]    As the compound characters of the fiberglass  50  and the resin  60  described above, in using the fiberglass  50  reinforcing the resin  60 , the plentiful shorter fiberglass  50  can be instead of longer fiberglass  50  so as to mix the fiberglass  50  with the resin  60  easily and reduce the cost and difficulty to manufacture. 
         [0176]    It is worth mentioning that another advantage that made the casing tube  10  in the fiberglass reinforced resin composite is the fiberglass reinforced resin composite has excellent insulation ability. Even in the extreme environment, like the humid environment, for long the insulation ability of the casing tube  10  is hard to be effected. So, the continuity of the signal transmission of the railway transportation system can be guaranteed effectively to ensure security of transportation. 
         [0177]    As in  FIG. 10 , for ensuring the strength of the thread portion  121  of the casing tube  10 , each of the tube bodies  11  comprises a first body  101  and a second body  102 , wherein the first body  101  is overlapped with the second body  102  to cover the second body  102 . The thread portion  121  is provided on the second body  102 . The first body  101  is made of the fiberglass reinforced resin composite formed by long fiberglass and resin mixed with each other, wherein the second body  102  is made of the fiberglass reinforced resin composite formed by short fiberglass and resin mixed with each other. 
         [0178]    Another preferred embodiment of the present invention is shown in  FIG. 13  and  FIG. 14 . The casing tube  10 A comprises at least two tube bodies  11 A each having an arc-shape, wherein each of the tube bodies  11 A has a first side portion  110 A and a second side portion  120 A, wherein the first side portion  110 A and the second side portion  120 A are extended radially and outwardly from the tube bodies  11 A respectively. 
         [0179]    Each of the tube bodies  11 A further has an inner-side surface  130 A and an outer-side surface  140 A corresponding to the inner-side surface  130 A, wherein each of the inner-side surface  130 A and outer-side surface  140 A are extended curvedly between the first side portion  110 A and the second side portion  120 A respectively to form the arc-shaped tube bodies  11 A respectively. 
         [0180]    Furthermore, the tube body  11 A has at least one retaining element  111 A integrally formed on the inner-side surface  130 A. As the tube bodies  11 A are fittingly coupled with each other edge-to-edge to form the casing tube  10 A, the inner-side surfaces  130 A of the tube bodies  11 A form a screw channel  12 A and each of the retaining elements  111 A of each of the tube bodies  11 A is correspondingly matched with each other to form a thread portion  121 A for the screw  20 A screwing thereat. It is worth mentioning that the thread portion  121 A is designed according to the screw to be used actually. For example, sizes, clearance and so on of the thread portion  121 A are adjustable as required. 
         [0181]    The casing tube  10 A, in this preferred embodiment of the present invention, is constructed to have two tube bodies  11 A, wherein the two tube bodies  11 A are overlappedly coupled with each other edge-to-edge to form the screw channel  12 A between the inner-side surfaces  130 A of the tube bodies  11 A. One skilled in art will understand that in other embodiment of the present invention the casing tube  10 A can comprises more than two tube bodies  11 A. 
         [0182]    In addition, the casing tube  10 A further comprises at least one fastening unit  13 A for fastening the tube body  11 A. And as the casing tube  10 A is being used each of the fastening unit  13 A prevents relative movement of the casing tube  10 A so as to ensure the reliability of the casing tube  10 A. For the casing tube  10 A of the present invention, each of the fastening units  13 A is encircled around the casing tube  10 A to fasten the tube bodies  11  together. In details, the method for manufacturing the casing tube  10 A comprises steps as following. 
         [0183]    Step A: Couple the tube bodies  11 A together, wherein the first side portion  110 A and the second side portion  120 A of the tube bodes  11 A are coupled with each other, and the inner-side surfaces  130 A of the tube bodies  11 A form the screw channel  12 A. 
         [0184]    Step B: Bind each of the fastening units  13 A around the outer-side surfaces  140 A of the tube bodies  11 A for fastening the tube bodies  11 A together to form the casing tube  10 A. 
         [0185]    In other words, the casing tube  10 A in the present invention, each of the tube bodies  11 A is fastened by binding the fastening unit  13 A. Thus, as one of the tube bodies  11 A is forced to tend to move relatively, the fastening unit  13 A provides a binding force to stop relative movement between the tube bodies  11 A to ensure the reliably of the casing tube  10 A in application. In this way, during the molding process of the sleeper, the casing tube  10 A can be pre-embedded in position. And during the flow of mold material for forming the sleeper, because each of the tube bodies  11 A is fastened by the fastening unit  13 A, the impact of flow of mold material for forming the sleeper to each of the tube bodies  11 A will not cause each of the tube bodies  11 A of the casing tube  10 A to move relatively so as to prevent the malposition of the tube body  11 A. So, by ensuring the thread portion  121 A formed by the retaining elements  111 A of the tube bodies  11 A without malposition, the quality of each of the casing tube  10 A can be ensured. 
         [0186]    Otherwise, the outer-side surface  140 A of each of the tube bodies  11 A has at least one locating element  14 A formed in an annular shape. Each of the locating element  14 A is integrally and coaxially protruded from the outer-side surface  140 A of the tube body  11 A so that every two of the adjacent locating element  14 A form a locating slot  141 A therebetween. As the casing tube  10 A is fastened at the position of the sleeper  40 A the material made the sleeper  40 A will flow to fulfill in space of the locating slot  141 A. 
         [0187]    After the sleeper  40 A is molded, the sleeper  40 A is meshed with the casing tube  10  to prevent the tube bodies  11 A moving reciprocatedly under vibrations which the locating element  14 A will stop movement of the casing tube  10 A for fastening the casing tube  10 A on the preset position. 
         [0188]    As shown in  FIG. 13 , in the casing tube  10 A of the present invention, the locating elements  14 A of the tube bodies  11 A are corresponding positioned. In other words, after the tube bodies  11 A formed the casing tube  10 A, the locating elements  14 A of the tube bodies  11 A are aligned with each other end-to-end and are encircled around the outer wall of the casing tube  10 A. As the casing tube  10 A of the preferred embodiment of the present invention in  FIG. 15 , the position of the locating elements  14 A of the tube bodies  11 A can be misaligned with each other. After the tube bodies  11 A formed the casing tube  10 A, the locating elements  14 A of the tube bodies  11 A is staggered around the outer wall of the casing tube  10 A. In other words, the locating elements  14 A at the tube bodies  11 A are alternating with each other. In these kinds of aspects the invention is not restricted. 
         [0189]    Further, the first side portion  110 A and the second side portion  120 A of the tube body  11 A are extended form the inner-side surface  130 A to the outer-side surface  140 A of the tube body  11 A, and the first side portion  110 A and the second side portion  120 A are protruded from the outer-side surface  140 A of the tube body  11 A. In other words, the thickness of the first side portion  110 A and the second side portion  120 A of the tube bodies  11 A are larger than thickness of other portions, or the thickness between the inner-side surface  130 A and the outer-side surface  140 A is smaller than thickness of the first side portion  110 A and the second side portion  120 A of the tube body  11 A. In this way, as the tube bodies  11 A are provided fitly to form the casing tube  10 A, the contact area of each of the tube bodies  11 A can be increased so as to prevent malposition and rotation of each of the tube bodies  11 A by the first side portion  110 A and the second side portion  120 A of the tube bodies  11 A. Also, with increasing the contact area of each of the tube bodies  11 A, the gap between the first side portion  110 A and the second side portion  120 A of the tube body  11 A can be reduced effectively to ensure the sealing between the tube bodies  11 A of the casing tube  10 A. By this means, when the casing tube  10 A is pre-embedded at the corresponding position of the sleeper, the flowing material for forming the sleeper will not pass through the gap between of the tube bodies  11 A to permeate into the screw channel  12 A. 
         [0190]    In addition, in the casing tube  10 A of the present invention, one of the tube bodies  11 A has a holding member  150 A protruded from at the first side portion  110 A and the second side portion  120 A as the protrusion, and a holding slot  160 A indented from the first side portion  110 A and the second side portion  120 A as the protrusion as the slot. In other words, the holding member  150 A is located at an outer edge of the first side portion  110 A and the holding slot  160 A is located at an inner edge of first side portion  110 A of one tube body  11 A. Correspondingly, the holding member  150 A is located at an inner edge of the second side portion  120 A and the holding slot  160 A is located at an outer edge of second side portion  120 A of another tube body  11 A. As the tube bodies  11 A are coupled with each other to form the casing tube  10 A, the holding member  150 A and the holding slot  160 A of one tube body  11 A are inter-engaged with the holding slot  160 A and the holding member  150 A of the another tube body  11 A respectively. In this way, it is not only the malposition and the rotation of the tube bodies  11 A can be stopped effectively, but the sealing between the tube bodies  11 A for forming the casing tube  10 A can be improved. 
         [0191]    Also, the casing tube  10 A further comprises a binding layer  15 A which is between the first side portion  110 A and the second side portion  120 A of the tube bodies  11 A. In other words, the binding layer  15 A are sandwiched between the first side portion  110 A and the second side portion  120 A of the tube bodies  11 A for adhering the first side portion  110 A and the second side portion  120 A of the tube bodies  11 A together. And the binding layer  15 A can help the sealing between the tube bodies  11 A to form the casing tube  10 A better. 
         [0192]    As shown in  FIG. 16  and  FIG. 17 , a casing tube  10 B according to another preferred embodiment of the present invention is illustrated. The casing tube  10 B has the similar structural configuration of the above preferred embodiment, expect the casing tube  10 B having an integrated structure. 
         [0193]    Specifically, the casing tube  10 B comprises a tube body  11 B, having a hollow structure, which has an inner-side surface  130 B and an outer-side surface  140 B corresponding to the inner-side surface  130 B, wherein the inner-side surface  130 B of the tube body  11 B defines a screw channel  12 B therewithin. The inner-side surface  130 B of the tube body  11 B has a thread portion  121 B for meshing the screw inside the screw channel  12 B. 
         [0194]    In other words, in this preferred embodiment, the casing tube  10 B comprises the only one tube body  11 B. In this way, the reliability of the casing tube  10 B pre-embedded in the sleeper can be improved. 
         [0195]    The tube body  11 B has at least one locating element  14 B integrally protruded from the outer-side surface  140 B thereof for ensuring the reliability of the casing tube  10 B pre-embedded in the sleeper. As shown in  FIG. 16 , in this preferred embodiment of the present invention, the locating element  14 B can be extended spirally from one end of the tube body  11 B to the other end of the tube body  11 B, such as from the top end to the bottom end. In other words, the locating element  14 B can form in spiral structure. When the casing tube  10 B is pre-embedded at corresponding position, the flowing material forming the sleeper will flow along spiral slot of spiral structure of the tube body  11 B so as to fasten the casing tube  10 B in the preset position. 
         [0196]      FIG. 18  illustrates an alternative mode of the locating elements  14 B which are spacedly provided on the outer-side surface  140 B of the tube body  11 B to form a locating slot  141 B between every two of the adjacent locating elements  14 B. As the casing tube  10 B is pre-embedded in the corresponding position of the sleeper, the material made the sleeper will flow to fulfill in space of the locating slot  141 B. Thus, after the sleeper is molded, the casing tube  10 B is meshed with the sleeper to prevent the casing tube  10 B trends to move reciprocatedly under vibrations which each of the locating elements  14 A will stop movement of the casing tube  10 B for fastening the casing tube  10 A on the preset position by each of the locating element  14 B. 
         [0197]    As shown in  FIG. 19A  to  FIG. 19E , the manufacture method for making the casing tube  10  of the present invention has disclosed. 
         [0198]    Firstly, the fiberglass  50  and the resin  60  are mixed together to form mixture of fiberglass and resin in strip shape. One skilled in the art will understand that which mixing the fiberglass  50  with the resin  60 , the kneader may be used to fully mix the fiberglass  50  with the resin  60  to make the mixture of fiberglass and resin in strip shape. Also using the flowability of resin make the resin  60  permeate into gaps of the bunches fiberglass  50  to make the mixture of fiberglass and resin in strip shape. 
         [0199]    Secondly, a mould core  1000  is provided to bind the strip-shape mixture of fiberglass and resin on the mould core  1000  to make the billets of the casing tube  10 . It is understandable that the mixture of fiberglass and resin made the mould core  1000  has a free end which adhered on the mould core  1000  to begin to bind. Also the mixture of fiberglass and resin bound on the mould core  1000  provides bonding force to the free end for melting the free end into the mixture of fiberglass and resin. Accordingly, after the billets of the casing tube  10  is made and the mixture of fiberglass and resin is cut down, the mixture of fiberglass and resin forms a tail end which is pressed to melt in the mixture of fiberglass and resin to form a whole billets of the casing tube  10 . It is worth mentioning that one whole bunches of the strip-shape mixture of fiberglass and resin can make one or more the billets of the casing tube  10 . Also it is worth to mention that several whole bunches of the strip-shape mixture of fiberglass and resin can make one billets of the casing tube  10 . In this case, the free end of the mixture of fiberglass and resin will be completely melted into the mixture of fiberglass and resin. 
         [0200]    One skilled in the art will understand that, as binding the mixture of fiberglass and resin on the mould core  1000 , one is driving the mould core  1000  to rotate which will bind the strip-shape mixture of fiberglass and resin on the mould core  1000 , the other is rotating the strip-shape mixture of fiberglass and resin around the mould core  1000  to bind the mixture of fiberglass and resin on the mould core  1000 . Also, the mould core  1000  has arranged with thread structure and the diameter of the mould core  1000  can be chose as required. The casing tube  10  can form the thread portion  121  inside via thread structure of the mould core  1000 . 
         [0201]    It is worth mentioning that the material of the mould core  1000  is alloy steel, so as not to cohere the mixture of fiberglass and resin on the mould core  1000  for demolding later. Preferably, the mould core  1000  is in type 9SiCr, which during the heat treatment of the mixture of fiberglass and resin the molded casing tube  10  won&#39;t be deformed. 
         [0202]    It is also worth mentioning that, before binding the mixture of fiberglass and resin, the mould core  1000  is coating with releasing agent for removing the molded casing tube  10  from the mould core  1000  later. For example, the mould core  1000  can be removed from the molded casing tube  10  in a rotating way. Otherwise, for easily demolding of the mould core  1000 , the mould core  1000  has taper which size of far end of mould core  1000  is a little smaller than near end of the mould core  1000 . 
         [0203]    Then, the billets of the casing tube  10  are pressed to mold the mixture of fiberglass and resin. Finally, the casing tube  10  is removed from the mould core  1000  by the demolding process to obtain the casing tube  10 . 
         [0204]    Preferably, the mould for pressing the billets of the casing tube  10  further has grooves to form each of the locating element  14  on the outer surface of the molded casing tube  10 . 
         [0205]    Preferably, the casing tube  10  is trimmed for make surface of the casing tube  10  smooth. 
         [0206]    As in  FIG. 20 , the manufacture method of the casing tube  10  in the present invention comprises the following steps. 
         [0207]    Step 1: preparing a mixture of fiberglass and resin, wherein the mixture has a strip shape; 
         [0208]    Step 2: binding the mixture on a mould core  1000  to obtain a billet for the casing tube; 
         [0209]    Step 3: mould pressing the billet to fasten and mold the billet; and 
         [0210]    Step 4: demolding and removing the mould core to obtain the casing tube  10 . 
         [0211]    It is worth mentioning that, in Step 4, first demolding, then removing the mould core  1000  to obtain the casing tube  10 ; or first removing the mould core  1000 , then demolding to obtain the casing tube  10 . In these kinds of aspects the invention is not restricted. 
         [0212]    In one embodiment, in Step 1, further comprises: 
         [0213]    Step 1.1: mixing the fiberglass  50  and the resin  60  to prepare the mixture; and 
         [0214]    Step 1.2: bunching the mixture to make the mixture have a bunch shape. One skilled in the art will understand that, during the process, the fiberglass  50  can be soaked in the resin  60  to make the resin  60  fully permeated into gaps of the fiberglass  50  to form mixture of fiberglass and resin. Then dealing the mixture of fiberglass and resin in bunches process and form the mixture of fiberglass and resin in bunches shape. 
         [0215]    In other embodiment, in Step 1, further comprises: 
         [0216]    Step 1.3: making the fiberglass  50  have a bunch shape. 
         [0217]    Step 1.4: making the resin  60  permeate into the gaps of the fiberglass  50  to form the mixture having a strip shape. One skilled in the art will understand that, in this step, first making the fiberglass  50  in bunches shape, then the fiberglass  50  is permeated in to the gaps of the resin  60  to form mixture of fiberglass and resin by the flowability of the fiberglass  50 . 
         [0218]    Preferably, the Step 1.4 further comprises the steps of: 
         [0219]    soaking the fiberglass  50  in the resin  60  for the resin  60  permeating into the gaps of the fiberglass  50 . 
         [0220]    Preferably, the Step 1.4 further comprises the steps of: 
         [0221]    making the resin  60  flow through the bunches shape fiberglass  50  for the resin  60  permeating into the gaps of the fiberglass  50 . 
         [0222]    Otherwise, the manufacturing method of the casing tube  10  further comprises: 
         [0223]    Step 5: trimming the casing tube  10  for make surface of the casing tube  10  smooth. 
         [0224]    For obtaining the casing tube  10 , as in  FIG. 21 , there is a manufacturing method which comprises steps as following. 
         [0225]    (a) Mix the fiberglass  50  and the resin  60  to get a mixture of fiberglass and resin. 
         [0226]    In details, using the kneader to fully mix the fiberglass  50  with the resin  60 . What needs to explain is that according to the requirement of manufacture and other limitations there are other ways to mix the mixture of the fiberglass the resin. In the above embodiment of the present invention, provided kneader is an example to illustrate application of mixing the mixture of fiberglass and resin which explains the heart of present invention. 
         [0227]    (b) Press the mixture of fiberglass and resin to composite and mold the mixture of fiberglass and resin for obtaining a tube body  11 , wherein the tube body  11  has at least a retaining element  111 . 
         [0228]    (c): Couple at least two the tube bodies  11  with each other to define a screw channel  12  therebetween, wherein the retaining element  111  is located in the screw channel  12  to define the casing tube  10 . 
         [0229]    Further, the manufacturing method further comprises the step of: 
         [0230]    (d) Proving at least a fastening unit  13  on the outer surface of the casing tube  10  to fasten each of the tube bodies  11 . 
         [0231]    Preferably, in step (d), binding the strip mixture of fiberglass and resin on the outer surface of the casing tube  10  so as to form the fastening unit  13  by the strip mixture of fiberglass and resin. 
         [0232]    More preferably, in an embodiment of the present invention, soaking the fiberglass in the resin to permeate the resin into the gaps of fiberglass bunches, so as to form the fastening unit  13 ; in another embodiment of the present invention, making the resin flow through the fiberglass bunches to permeate the resin into the gaps of fiberglass bunches to form the fastening unit  13 . 
         [0233]    Preferably, in step (b), on the outer surface of each of the tube bodies  11  forming at least one locating element  14 , wherein each of the locating elements  14  is enforced meshing force between the casing tube  10  and the sleeper  40  to fasten the casing tube  10  in the sleeper  40 . Furthermore, in step (b), overlapping the mixture of fiberglass and resin made by the long fiberglass and resin and the mixture of fiberglass and resin made by the short fiberglass and resin with each other, for forming each of the locating element  14  made by the mixture of fiberglass and resin made by the long fiberglass and resin and forming each of the tube bodies  11  made by the mixture of fiberglass and resin made by the short fiberglass and resin. 
         [0234]    Furthermore, the manufacture method further comprises the steps of: 
         [0235]    (e) proving a binding layer  15  between the tube bodies  11  for connecting the tube bodies  11  with each other, such that the sealing of the tube bodies  11  of the casing tube  10  will be better. 
         [0236]    As in  FIG. 22 , the present invention has disclosed a manufacturing method to make the casing tube  10  by the fiberglass reinforced resin composite, which comprises steps as following. 
         [0237]    (1) preparing the fiberglass reinforced resin composite; 
         [0238]    (2) making the fiberglass reinforced resin composite material be in a sol state; and 
         [0239]    (3) gelling the fiberglass reinforced resin composite material via the casing tube module and demolding to obtain the casing tube  10 , wherein the casing tube  10  has a screw channel  12  and a thread portion  121  provided in the screw channel  12 . 
         [0240]    Further, before step (1), the method comprises the steps of: 
         [0241]    (1.1) mixing fiberglass and resin to obtain a mixture of the fiberglass and resin; and 
         [0242]    (1.2) heating and/or pressing the mixture of fiberglass and resin to composite the fiberglass and resin and form the fiberglass reinforced resin composite in sol state. 
         [0243]    Furthermore, the step (1.2) further comprises the steps of: 
         [0244]    (1.2.1) forming the fiberglass reinforced resin composite material in sol state by long fiberglass reinforced resin; 
         [0245]    (1.2.2) forming the fiberglass reinforced resin composite material in sol state by short fiberglass reinforced resin; and 
         [0246]    (1.2.3) overlapping the two fiberglass reinforced resin composite materials in the step (1.2.1) and the step (1.2.2). 
         [0247]    The step (3) further comprises the steps of: 
         [0248]    (3.1) forming at least two tube bodies  11 ; and 
         [0249]    (3.2) coupling at least two tube bodies  11  with each other to form the screw channel  12  therewithin to obtain the casing tube  10 . 
         [0250]    Also, after the step (3.2), the method further comprises a step of: 
         [0251]    binding the strip mixture of fiberglass and resin on the outer surface of the casing tube  10  so as to form the fastening unit  13  by the strip mixture of fiberglass and resin. 
         [0252]    As shown in  FIG. 23 , the present invention provides a manufacturing method of a casing tube  10 , wherein the method comprises: 
         [0253]    (I) Providing at least two tube bodies  11 , wherein each of the tube bodies  11  has a curved inner-side surface  130  and at least a retaining element  111  provided on the inner-side surface  130 ; and 
         [0254]    (II) Coupling the tube bodies  11  with each other to define a screw channel  12  within the inner-side surfaces  130  of the tube bodies  11  to obtain the casing tube  10 , wherein each of the retaining elements  111  is provided in the screw channel  12 . 
         [0255]    Preferably, the manufacturing method further comprises the step of: 
         [0256]    (III) binding at least one fastening unit  13  on the tube body  11 , wherein the fastening unit  13  fastens the tube bodies  11  together. 
         [0257]    As in  FIG. 24 , the present invention has disclosed a method to manufacture the casing tube  10 , which comprises steps as follows. 
         [0258]    (A) preparing a billet for the tube body  11 , wherein the size of the billet is no less than the size of tube body  11 ; 
         [0259]    (B) cutting the billet to obtain the tube body  11 , wherein the tube body  11  has a curved inner-side surface  130  and at least one retaining element  111  provided on the inner-side surface  130 ; and 
         [0260]    (C) coupling at least two tube bodies  11  to define a screw channel  12  within the inner-side surfaces  130  of the tube bodies  11  to obtain the casing tube  10 , wherein each of the retaining elements  111  is provided in the screw channel  12 . 
         [0261]    Preferably, the step (A) comprises the steps of: 
         [0262]    (A.1) putting the unmolded material in the mould for the billets of tube body  11 ; and 
         [0263]    (A.2) heating and/or pressing the unmolded material via the mould for the billet of the tube body  11  to obtain the billet. 
         [0264]    Further, the manufacturing method further comprises the step of: 
         [0265]    (D) binding at least one fastening unit  13  on the tube body  11 , wherein the fastening unit  13  fastens the tube bodies  11  together. 
         [0266]    Furthermore, the manufacturing method further comprises a step of: 
         [0267]    arranging a binding layer  15  between a connection between the tube bodies  11  for connecting the tube bodies  11  with each other. 
         [0268]    As shown in  FIG. 25  to  FIG. 28 , a casing tube  10 C of another preferred embodiment according to the present invention is illustrated. As shown in  FIG. 25 , a railway transportation system comprises at least one casing tube  10 C, at least one screw  20 C, at least one rail  30 C and at least one sleeper  40 C, wherein one casing tube  10 C and one screw  20 C are correspondingly matched with each other to be pre-embedded in preset position of the sleeper  40 C, wherein with a nut the rail  30 C can be rapidly fastened in the sleeper  40 C to improve efficiency of laying the railway transportation system. 
         [0269]    In details, in this embodiment of the present invention, the casing tube  10 C comprises a tube body  11 C which has an inner-side surface  130 C and an outer-side surface  140 C corresponding to the inner-side surface  130 C, wherein the inner-side surface  130 C of the casing tube  10 C defines a screw channel  12 C for engaging with the screw  20 C. It is worth mentioning that one screw  20 C can be match to one casing tube  10 C to be pre-embedded in the sleeper  40 C. Furthermore, the screw  20 C can move alone the screw channel  12 C of the casing tube  10 C, and the direction of movement is same as the extension direction of the screw channel  12 C of the casing tube  10 C. In this way, when laying the railway transportation, the screw  20 C can be adapted to different size of the rail  30 C. 
         [0270]    As in  FIG. 27  and  FIG. 28 , the tube body  11 C has an upper opening  112 C and a bottom opening  113 C, which the upper opening  112 C and the bottom opening  113 C are communicated with the screw channel  12 C. The top end of the screw  20 C can be through the bottom opening  113 C of the tube body  11 C into the screw channel  12 C of the tube body  11 C and, further, out of the upper opening  112 C. Thus, after the top end of the screw  20 C is through the rail  30 C, the rail  30 C is locked on the sleeper  40 C by the matched nut. The bottom end of the screw  20 C can be remained in the screw channel  12 C of the tube body  11 C. It is worth mentioning that the size of the upper opening  112 C of the tube body  11 C is smaller than the size of the screw channel  12 C of the tube body  11 C, and the size of the upper opening  112 C of the tube body  11 C is larger than the size of bottom end of the screw  20 C. In this way, as the screw  20 C bears force, the screw  20 C will not slide out of the screw channel  12 C of the tube body  11 C. Thus, the nut and the screw  20 C can match with each other to lock the rail  30 C on the sleeper  40 C. 
         [0271]    Furthermore, the outer-side surface  140 C of the tube body  11 C has at least one locating element  14 C for stably pre-embedded the casing tube  10 C in the sleeper  40 C. In details, every two of the adjacent locating elements  14 C form a locating slot  141 C. As the casing tube  10 C is fastened at the preset position of the sleeper  40 C, the material made the sleeper  40 C will flow to permeate in the locating slot  141 C of the locating element  14 C to generate meshing force between the casing tube  10 C and the sleeper  40 C. As the casing tube  10 C is bearing sustainably vibrations, each of the locating elements  14 C will stop movement of the casing tube  10 C to ensure the stability of the casing tube  10 C. 
         [0272]    In other embodiment of the present invention, the tube body  11 C forms a line of positioner. Thus as the casing tube  10 C is pre-embedded in the sleeper  40 C, each of the positioner is in different height. According to requirement, the bottom end of the screw  20 C can be placed at different height of the positioner, so as to make the part of screw  20 C which is out of the upper opening  112 C of the tube body  11 C adjustable. 
         [0273]      FIG. 29  and FIG. rail  30  are shown an alternative mode of the above embodiment of the present embodiment. In details, the casing tube  10 D comprises at least two tube bodies  11 D, wherein each of the tube bodies  11 D has an inner-side surface  130 D and an outer-side surface  140 D corresponding to the inner-side surface  130 D. As the tube bodies  11 D are coupled with each other to form the casing tube  10 D, the inner-side surfaces  130 D of the tube bodies  11 D forms a screw channel  12 D for engaging with the screw  20 D. The outer-side surface  140 D of each of the tube bodies  11 D will contact to the sleeper  40 D. 
         [0274]    Furthermore, each of the tube bodies  11 D has at least one locating element  14 D protruded from the outer-side surface  140 D for pre-embedding stably the casing tube  10 D in the sleeper  40 D. In details, every two of the adjacent locating elements  14 D forms a locating slot  141 D therebetween. As the casing tube  10 D is fastened at the preset position of the sleeper  40 D, the material made the sleeper  40 D will flow to permeate in the locating slot  141 D of the locating element  14 D to generate meshing force between the casing tube  10 D and the sleeper  40 D. As the casing tube  10 D bears sustainably vibrations, each of the locating elements  14 D will stop movement of the casing tube  10 D to ensure the stability of the casing tube  10 D. 
         [0275]    As the tube bodies  11 D are coupled with each other to form the casing tube  10 D, the tube body  11 D has an upper opening  112 D and a bottom opening  113 D, which the upper opening  112 D and the bottom opening  113 D are communicated with the screw channel  12 D. The top end of the screw  20 D can be through the bottom opening  113 D of the tube body  11 D into the screw channel  12 D of the tube body  11 D and, further, out of the upper opening  112 D. Thus, after the top end of the screw  20 D is through the rail  30 D, the rail  30 D is locked on the sleeper  40 D by the matched nut. The bottom end of the screw  20 D can be remained in the screw channel  12 D of the tube body  11 D. It is worth mentioning that the size of the upper opening  112 D of the tube body  11 D is smaller than the size of the screw channel  12 D of the tube body  11 D, and the size of the upper opening  112 D of the tube body  11 D is larger than the size of bottom end of the screw  20 D. In this way, as the screw  20 D is bearing force, the screw  20 D will not slide out of the screw channel  12 D of the tube body  11 D. Thus, the nut and the screw  20 D can match with each other to lock the rail  30 D on the sleeper  40 D. 
         [0276]    The casing tube  10 D further comprises one or more fastening units  13 D, wherein the fastening units  13 D are spacedly encircled around outer surface of the casing tube  10 D to fasten the tube bodies  11 D together. So, each screw  20 D is not only sealed the gap of contact between the tube body  11 D better, but also prevented malposition of the tube body  11 D under stress by each of the fastening units  13 D when the casing tube  10 D bears transverse impact force to ensure stability of structure of the casing tube  10 D. It is understandable for one skilled in the art, the sleeper  40 D is usually made of some material like the ferroconcrete which has larger liquidity while not shaped. As the casing tube  10 D is provided at the preset position, and the sleeper  40 D is molded during the molding process, the flow of material made the sleeper  40 D will generate transverse impact force to the casing tube  10 D to make the tube body  11 D tend to be malposition. Then, each of the fastening units  13 D prevents the tube body  11 D to be malposition. Therefore, the material made the sleeper  40 D will not be permeated into the screw channel  12 D through the gap of contact between the tube bodies  11 D. Also the thread portion  121 D inside the screw channel  12 D formed by the casing tube  10 D will not be malposition. 
         [0277]    One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
         [0278]    It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.