Rail tensioner connecting shaft

Abstract

To provide a connecting shaft for a rail tensioner that can reduce costs while preventing the shaft body and clamping portion from coming loose. [Solution] A rail tensioner connecting shaft 30 is used in a rail tensioner 100 which has a first fixing device 10 that grips the front rail 1, a second fixing device 20 that grips the rear rail 2, and a hydraulic cylinder 14 provided on the first fixing device 10 of the first and second fixing devices 10, 20 which is capable of extending and retracting the piston rod 15, and connects the piston rod 15 and the second fixing device 20, and has a shaft body portion 31 formed of general structural rolled steel material with male threaded portions 311 formed at both ends, and first and second fastening portions 32, 33 formed of heat-treated machine structural carbon steel material which can be fastened to both ends of the shaft body portion 31, respectively.

Description

Technical Field

[0001] The present invention relates to a connecting shaft for a rail tensioner that is used in a rail tensioner and connects a cylinder that pulls a rail and a fixture that grips the rail.

Background Art

[0002] Conventionally, a rail tensioner that pulls a rail during rail laying and replacement has been known (for example, Patent Document 1). In the rail tensioner described in Patent Document 1, first and second fixtures are connected to both ends of two parallel rods, and have a pair of arms, a connecting plate that connects these pair of arms, and a clamp member. The arm has a connecting portion that protrudes laterally at one end and is rotatably attached to the connecting plate. Further, the other end of the arm of the first fixture is rotatably attached to a hydraulic cylinder in which a piston rod is connected to one end of the rod, and the arm of the second fixture is rotatably attached to the other end of the rod.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Railway rails are increasingly being made longer to improve ride comfort and reduce noise. In the case of long rails, the amount of expansion and contraction due to temperature changes is greater than that of standard-length rails, so it is necessary to increase the tension applied to the joints where the rails are joined by welding. If the tension is increased, the clamping parts (2-point clevis) and clamped parts (1-point clevis) provided at both ends of the rod may be pulled out from the main rod body, and there is a risk that the target tension cannot be applied to the rail. In particular, when a three-part structure is adopted in which the main rod body and the clamping parts (clamped parts) are mechanically connected using a screw structure in order to reduce costs, the likelihood of detachment increases even more when the screw part wears down due to aging.

[0005] Therefore, the present invention aims to provide a connecting shaft for a rail tensioner that can suppress the detachment of the shaft body and the clamping portion while reducing costs. [Means for solving the problem]

[0006] The rail tensioner connecting shaft of the present invention is used in a rail tensioner having a first fixing device for gripping one rail, a second fixing device for gripping the other rail, and a cylinder provided on one of the first and second fixing devices that allows a piston rod to extend and retract, and connects the piston rod to the other of the first and second fixing devices, and is characterized by having a shaft body made of general structural rolled steel material with male threaded portions formed at both ends, and a pair of fastening portions made of heat-treated machine structural carbon steel material that can be fastened to each end of the shaft body.

[0007] According to this invention, the connecting shaft can be constructed with three parts, which reduces manufacturing costs compared to when the connecting shaft is constructed with a single structure. Furthermore, the strength and hardness of the pair of fastening parts can be increased, and wear of the threaded part connected to the shaft body can be suppressed, thereby preventing the shaft body and fastening part from coming loose.

[0008] Furthermore, the pair of fastening parts comprises a first fastening part having a first connecting body that is connected to the piston rod and a first female thread that is integrally formed with the first connecting body and can be fastened to one end of the shaft body; and a second fastening part having a second connecting body that is connected to the other of the first and second fasteners and a second female thread that is integrally formed with the second connecting body and can be fastened to the other end of the shaft body, wherein the axial length of the threaded portion of the first and second female threads is set to 60% or more of the axial length of the first and second female threads.

[0009] According to the above configuration, the fastening area between the shaft body and the female threaded portion can be enlarged, so that even if the threaded portion is partially worn due to aging, an effective fastening area can be secured. Therefore, the slippage between the shaft body and the clamping portion can be reliably prevented.

[0010] Furthermore, of the first and second connecting body portions, one is formed in the shape of a single clevis and the other in the shape of a double clevis, and in a plan view, the single-clevis connecting body portion is formed in a substantially rectangular shape, and the double-clevis connecting body portion is formed in a substantially semi-elliptical shape.

[0011] According to the above configuration, the strength of the single-clevis type connecting body can be increased in order to ensure sufficient wall thickness of the single-clevis type connecting body. Therefore, the strength of the single-clevis type connecting body can be increased while improving mounting performance. [Effects of the Invention]

[0012] According to this invention, it is possible to reduce costs while preventing the shaft body and the clamping portion from coming loose. [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view showing the tensioner according to an embodiment of the present invention set on a rail. [Figure 2] The connecting shaft according to this embodiment is shown as follows: (a) is a plan view and (b) is a side view. [Figure 3] This is a diagram showing the shaft body according to this embodiment. [Figure 4] The first fastening part according to this embodiment is shown as follows: (a) is a plan view, (b) is a side view, (c) is a front view, and (d) is a rear view. [Figure 5] The second fastening part according to this embodiment is shown as follows: (a) is a plan view, (b) is a side view, (c) is a front view, and (d) is a rear view. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals and will not be repeated in the description.

[0015] First, with reference to Figure 1, a tensioner 100 equipped with a connecting shaft 30 according to an embodiment of the present invention will be described. For example, if a part of a long rail is cut to replace it outside of midsummer, the axial force in the tensile direction of the rail becomes zero and the cut joint opens up. Therefore, when joining a new rail, it is necessary to forcibly pull the rail together and apply tension to make it the same as the axial force before cutting before joining. This tensioner 100 is a device that applies tension to the rail. As shown in Figure 1, the tensioner 100 has a first fixing device 10, a second fixing device 20, and a pair of connecting shafts 30. Hereinafter, the two rails to be joined may be referred to as the front rail 1 and the rear rail 2.

[0016] The first fixing device 10 grips the underside of the front rail 1 from both sides in the rail width direction. The first fixing device 10 has a pair of first arms 11, a first connecting plate 12, and a pair of first clamps 13. The pair of first arms 11 are formed in an elongated shape, with a first connecting portion 111 provided at one end in the longitudinal direction of each. The first connecting plate 12 is formed in an elongated plate shape, with the first connecting portion 111 of one first arm 11 rotatably supported on one side and the first connecting portion 111 of the other first arm 11 rotatably supported on the other side. The pair of first clamps 13 clamp the front rail 1. These first clamps 13 are formed in a semicircular shape, with tooth-shaped grooves provided on the straight portion and the curved portion rotatably attached to the tip of the first arm 11 on one end in the longitudinal direction. A hydraulic cylinder 14 is attached to the tip of the first arm 11 on the other end in the longitudinal direction.

[0017] The hydraulic cylinder 14 extends and retracts a piston rod 15 that extends from a piston (not shown) toward a second fixing device 20. A hydraulic fluid supply means (not shown), such as a hydraulic pump, is connected to the hydraulic cylinder 14 to supply hydraulic pressure to the hydraulic cylinder 14. The hydraulic cylinder 14 has a cylinder clevis portion 141 at its base end and a piston rod 15 at its tip. The cylinder clevis portion 141 is, for example, a two-pronged clevis-type connecting portion having openings on each side. The cylinder clevis portion 141 is rotatably connected by inserting a connecting pin P1 after aligning the opening provided at the tip of the other end of the first arm 11 in the longitudinal direction with the opening of the cylinder clevis portion 141 itself. The piston rod 15 has a piston clevis portion 151 at its tip. The piston clevis portion 151 is, for example, a two-pronged clevis-type connecting portion having openings on each side. The piston clevis portion 151 is rotatably connected to the end of the connecting shaft 30 on the side of the first fixing device 10 via a connecting pin P2.

[0018] The second fixture 20 grips the abdomen of the rear rail 2 from the left and right in the rail width direction. The second fixture 20 includes a pair of second arms 21, a second connecting plate 22, and a pair of second clamps 23. Similar to the first arms 11, the pair of second arms 21 are formed in an elongated shape, and second connecting portions 211 are provided at one end portions in the longitudinal direction, respectively. The second connecting plate 22 is formed in an elongated plate shape, and the second connecting portion 211 of one second arm 21 is rotatably supported on one side portion, and the second connecting portion 211 of the other second arm 21 is rotatably supported on the other side portion. The pair of second clamps 23 sandwich the rear rail 2. These second clamps 23 are formed in a semi-circular shape, similar to the first clamps 13, and tooth-shaped grooves are provided in the linear portions, respectively. The curved portions are rotatably attached to the tip portions at one end side in the longitudinal direction of the second arms 21. An opening is provided at the tip portion at the other end side in the longitudinal direction of the second arm 21, and the tip portion at the other end side in the longitudinal direction of the second arm 21 is rotatably connected to the end portion on the second fixture 20 side of the connecting shaft 30 via a connecting pin P3.

[0019] Next, the operation and joining process procedure of this tensioner 100 will be described. When applying a tension force to the front rail 1 and the rear rail 2 using this tensioner 100, first, the middle portion of the front rail 1 is sandwiched by the pair of first arms 11 of the first fixture 10, and the middle portion of the rear rail 2 is sandwiched by the pair of second arms 21 of the second fixture 20.

[0020] Next, the first arm 11 and the second arm 21 are respectively connected using the hydraulic cylinder 14 and the connecting shaft 30 in a state where the piston rod 15 is greatly extended (advanced) with respect to the hydraulic cylinder 14. Specifically, the clevis connection is made by inserting the connecting pins P1, P2, and P3 into the respective openings.

[0021] Next, by operating the hydraulic pressure on the hydraulic cylinder 14 to shorten (retract) the piston rod 15 based on the hydraulic cylinder 14, the first and second arms 11, 21 rotate around the first and second connecting parts 111, 211 respectively, the first clamp 13 presses and clamps the middle part of the front rail 1, and the second clamp 23 presses and clamps the middle part of the rear rail 2.

[0022] If the piston rod 15 is further continuously shortened (retracted), the distance between the first and second fixtures 10, 20 gradually becomes shorter, and a tension force is applied to the clamped rails 1, 2. Then, with the joint formed by the end of the front rail 1 and the end of the rear rail 2 facing it at a predetermined distance, the joint is heated by the gas flame of the gas pressure welding device 40 and joined by welding. After the joints of the rails 1, 2 are joined, the piston rod 15 of the hydraulic cylinder 14 is extended (advanced) to release the clamping of the rails 1, 2 by the first and second fixtures 10, 20, and the joining process is completed.

[0023] Next, referring to FIGS. 1 to 5, a pair of connecting shafts 30 will be described. As described above, the pair of connecting shafts 30 connect the piston rod 15 and the second arm 21 (second fixture 20) respectively. As shown in FIG. 2, the connecting shaft 30 has a shaft main body part 31, a first fastening part 32, and a second fastening part 33. Since the pair of connecting shafts 30 have the same configuration, only one of the connecting shafts 30 will be described, and the description of the other connecting shaft 30 will be omitted.

[0024] The shaft main body part 31 is formed into a rod shape from a hot-rolled steel material for general structure (SS material). Specifically, the shaft main body part 31 is formed by molding the SS400 material without heat treatment. As shown in FIG. 3, male screw parts 311 are provided at both ends of the shaft main body part 31.

[0025] The male thread portion 311 has a smaller thread pitch compared to a metric coarse thread. The male thread portion 311 is a metric fine thread, for example, set to M40 with a pitch of 2. The male thread portion 311 on one end and the male thread portion 311 on the other end have the same configuration. As a result, even if heat treatment is omitted, the number of threads per unit length can be increased by reducing the pitch, thereby suppressing thread loosening due to aging deterioration.

[0026] As shown in Figure 2, the first and second fastening parts 32 and 33 are formed in a clevis structure using carbon steel material for machine structures (SC material). Specifically, S45C material is processed and then heat-treated. The first and second fastening parts 32 and 33 are machined (cut) and then heat-treated. In this embodiment, the first and second fastening parts 32 and 33 are heated to 450-500°C with a burner after machining and then rapidly cooled in oil at approximately 20°C. This improves strength and hardness despite being a simple method. In this embodiment, heat treatment is defined as a surface treatment that improves the strength and hardness of the material compared to before treatment by heating and then cooling.

[0027] As shown in Figure 1, the first fastening portion 32 (see Figure 2) is connected to the piston clevis portion 151 via a connecting pin P2. As shown in Figures 2 and 4, the first fastening portion 32 has a first connecting body portion 321 and a first female thread portion 322.

[0028] The first connecting body portion 321 is a single-clevis type clamped portion that is sandwiched between the piston clevis portion 151, which is a two-clevis type connecting portion. In plan view, the first connecting body portion 321 is formed in a substantially rectangular shape and has a first opening 321a that penetrates in the vertical direction. When connecting the first connecting body portion 321 and the piston clevis portion 151, the first opening 321a and the opening of the piston clevis portion 151 are aligned, and then the connecting pin P2 is inserted through each opening (see Figure 1).

[0029] The first female threaded portion 322 is screwed into the male threaded portion 311 on the first fixing device 10 side of the shaft body 31. In this embodiment, to prevent rust, adhesive is applied to the male threaded portion 311 of the shaft body 31, and after fastening the first female threaded portion 322, a 60 kg weight is attached and the shaft is suspended for 1 hour to allow the adhesive to harden. The first female threaded portion 322 is formed in a bottomed cylindrical shape and has a first threaded portion 322a with a threaded portion formed on its inner circumference. The axial length d1 of the first threaded portion 322a of the first female threaded portion 322 is set to 60% or more of the axial length D1 of the first female threaded portion 322. In this embodiment, it is set to approximately 78%. This makes it possible to enlarge the fastening area between the shaft body 31 and the first female threaded portion 322, so that an effective fastening area can be secured even if the first threaded portion 322a is partially worn down due to aging.

[0030] As shown in Figure 1, the second fastening portion 33 is connected to the second arm 21 (second fixing device 20) via a connecting pin P3. As shown in Figures 2 and 5, the second fastening portion 33 has a second connecting body portion 331 and a second female thread portion 332.

[0031] The second connecting body 331 is a two-pronged clevis-type clamping portion that clamps the other end of the second arm 21 in the longitudinal direction, which is a one-pronged clevis-type connecting portion. In plan view, the second connecting body 331 is formed in a substantially semi-elongated shape and has a second opening 331a that penetrates in the vertical direction. The thickness of the single (one-pronged) clevis of the second connecting body 331 is thinner than the thickness of the clevis of the first connecting body 321, and the thickness of the clevis of the first connecting body 321 is set to be thinner than the thickness of the clevis of the second connecting body 331 (total of two peaks). When connecting the second connecting body 331 to the other end of the second arm 21 in the longitudinal direction, the second opening 331a and the opening of the second arm 21 are aligned, and then the connecting pin P3 is inserted through each opening (see Figure 1).

[0032] The second female threaded portion 332 is screwed into the male threaded portion 311 on the second fixing device 20 side of the shaft body 31. Similar to the first female threaded portion 322, adhesive is applied to the male threaded portion 311 of the shaft body 31, and after fastening, a 60 kg weight is attached and the shaft is suspended for one hour. The second female threaded portion 332 is formed in a bottomed cylindrical shape and has a second threaded portion 332a with a threaded portion formed on its inner circumference. Similar to the first female threaded portion 322, the axial length d2 of the second threaded portion 332a of the second female threaded portion 332 is set to 60% or more of the axial length D2 of the second female threaded portion 332. In this embodiment, it is set to approximately 78%.

[0033] As described above, according to the configuration of this embodiment, the shaft body 31 is formed from inexpensive general structural rolled steel, and the first and second fastening parts 32 and 33 (a pair of fastening parts) are formed from heat-treatable carbon steel for machine structures, so that the connecting shaft 30 can be constructed with three parts. Therefore, compared to the case in which the connecting shaft 30 is constructed with a single structure, the manufacturing cost can be reduced. In addition, since the first and second fastening parts 32 and 33 (a pair of fastening parts) are formed from heat-treatable carbon steel for machine structures and are configured to be fastened to both ends of the shaft body 31, the strength and hardness of the first and second fastening parts 32 and 33 can be increased, and wear of the male threaded part 311 connected to the shaft body 31 can be suppressed. Therefore, the detachment of the shaft body 31 from the first and second fastening parts 32 and 33 can be suppressed.

[0034] Furthermore, the first and second fastening parts 32, 33 (a pair of fastening parts) include a first connecting body part 321 connected to the piston rod 15, and a first fastening part 32 having a first female threaded portion 322 integrally formed with the first connecting body part 321 and capable of being fastened to one end of the shaft body part 31; and a second connecting body part 331 connected to the second fixing device 20 (the other fixing device) of the first and second fixing devices 10, 20, and a second fastening part 33 having a second female threaded portion 332 integrally formed with the second connecting body part 331 and capable of being fastened to the other end of the shaft body part 31. The axial lengths of the first and second threaded portions 322a, 332a of the first and second female threaded portions 322, 332 are set to be 60% or more of the axial length of the first and second female threaded portions 322, 332. With this configuration, the fastening area between the shaft body 31 and the first and second female threaded portions 322 and 332 can be made larger compared to configurations where the axial length of the threaded portion is set to less than 60% of the axial length of the female threaded portion. Therefore, even if the threaded portion is partially worn due to aging, an effective fastening area can be secured. As an effective fastening area can be secured, the disengagement of the shaft body 31 and the first and second fastening portions 32 and 33 (clamping portion and clamped portion) can be reliably suppressed.

[0035] Furthermore, of the first and second connecting body sections 321 and 331, the first connecting body section 321 is formed as a single-clevis type, and the second connecting body section 331 is formed as a double-clevis type. In a plan view, the first connecting body portion 321 is formed in a roughly rectangular shape, and the second connecting body portion 331 is formed in a roughly semi-elliptical shape. With this configuration, in a side view, the first connecting body portion 321, which is of the single-clevis type, is formed in a roughly rectangular shape, and the second connecting body portion 331, which is of the double-clevis type, is formed in a roughly semi-elliptical shape, thus ensuring sufficient wall thickness for the first connecting body portion 321, which is of the single-clevis type. In order to ensure sufficient wall thickness for the first connecting body portion 321, which is of the single-clevis type, the strength of the first connecting body portion 321, which is of the single-clevis type, can be increased. Therefore, since the strength of the first connecting body portion 321, which is of the single-clevis type, can be increased, the mounting performance can be improved while increasing the strength of the first connecting body portion 321, which is of the single-clevis type.

[0036] Embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its essence. The drawings sometimes schematically show the components in order to facilitate understanding. The number of each component shown in the drawings may differ from the actual number due to the convenience of drawing creation. Furthermore, the components shown in the above embodiments are examples and are not particularly limiting, and various modifications are possible without substantially departing from the effects of the present invention.

[0037] In this embodiment, the hydraulic cylinder 14 was connected to the first fixing device 10, and a connecting shaft 30 was placed between the second fixing device 20 and the piston rod 15. However, this disclosure is not limited to this configuration. The hydraulic cylinder 14 may be connected to the second fixing device 20, and the connecting shaft 30 may be placed between the first fixing device 10 and the piston rod 15. Alternatively, the piston rod 15 may be connected to the first fixing device 10, and the connecting shaft 30 may be placed between the second fixing device 20 and the hydraulic cylinder 14. Furthermore, the piston rod 15 may be connected to the second fixing device 20, and the connecting shaft 30 may be placed between the first fixing device 10 and the hydraulic cylinder 14.

[0038] In this embodiment, considering productivity and cost, the first and second fastening parts 32 and 33 were subjected to a simple heat treatment in which they were heated to 450 to 500°C and then rapidly cooled. However, this disclosure is not limited to this. At a minimum, it is sufficient that the strength and hardness are improved by a heat treatment in which the carbon steel material for machine structures is heated and cooled. It is also possible to heat the first and second fastening parts 32 and 33 to the A1 transformation point (727°C) or higher and subject them to a quenching treatment that actively changes the microstructure of the material.

[0039] In this embodiment, the first fastening portion 32 was configured as a single-clevis-shaped clamping portion and the second fastening portion 33 as a double-clevis-shaped clamping portion, but this disclosure is not limited thereto. The first fastening portion 32 may be configured as a double-clevis-shaped clamping portion and the second fastening portion 33 as a single-clevis-shaped clamping portion. Alternatively, both the first and second fastening portions 32 and 33 may be configured as single-clevis-shaped clamping portions, or both may be configured as double-clevis-shaped clamping portions. Furthermore, both the first and second fastening portions 32 and 33 may have connection structures other than clevis types.

[0040] In this embodiment, the first and second fastening parts 32 and 33 were formed from S45C material, but this disclosure is not limited thereto. At a minimum, any carbon steel material for machine structures that can be improved in strength and hardness by heat treatment is acceptable, and it may be formed from S35C material, S50C material, S55C material, etc., or from other materials.

[0041] In this embodiment, the shaft body 31 was made of SS400 material, but the disclosure is not limited to this. At a minimum, it is sufficient to ensure a tensile strength of 400 N / mm or more without heat treatment, and it may be made of SS490 material, SS540 material, or other materials. [Explanation of Symbols]

[0042] 1: Front rail, 2: Rear rail, 10: First fixing device, 11: First arm, 12: First connecting plate, 13: First clamp, 14: Hydraulic cylinder, 15: Piston rod, 20: Second fixing device, 21: Second arm, 22: Second connecting plate, 23: Second clamp, 30: Connecting shaft, 31: Shaft body, 32: First fastening part, 40: Gas pressure welding device, 33: Second fastening part, 100: Tensioner 111: First connecting part, 141: Cylinder clevis part, 151: Piston clevis part, 211: Second connecting part, 311: Male thread part, 321: First connecting body part, 321a: First opening, 322: First female thread part, 322a: First thread portion, 331: Second connecting body part, 331a: Second opening, 332: Second female thread part, 332a: Second thread portion, P1: Connecting pin, P2: Connecting pin, P3: Connecting pin

Claims

1. A first fixing device that grips one of the rails, A second fixing device that grips the other rail, Used in a rail tensioner having a cylinder on one of the first and second fixing devices, in which a piston rod can be extended and retracted, A connecting shaft for a rail tensioner, which connects the piston rod and the other of the first and second fixing devices, The shaft body is made of general structural rolled steel and has male threaded portions formed at both ends, Formed from heat-treated carbon steel material for machine structures, the shaft body has a pair of fastening parts that can be fastened to each end, A connecting shaft for a rail tensioner, having the following features.

2. The pair of fastening parts are, A first connecting body portion connected to the piston rod, and a first fastening portion integrally formed with the first connecting body portion and having a first female thread portion that can be fastened to one end of the shaft body portion, A second connecting body portion connected to the other of the first and second fasteners, and a second fastening portion integrally formed with the second connecting body portion and having a second female thread portion that can be fastened to the other end of the shaft body portion, Equipped with, The rail tensioner connecting shaft according to claim 1, wherein the axial length of the threaded portion of the first and second female threaded portions is set to 60% or more of the axial length of the first and second female threaded portions.

3. Of the first and second connecting body parts, one is formed as a single-clevis type and the other as a double-clevis type. In a plan view, the single-clevis type connecting body is formed in a substantially rectangular shape, and the double-clevis type connecting body is formed in a substantially semi-elliptical shape, as described in claim 2, for a rail tensioner connecting shaft.

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