Dual-purpose connecting system tractor for full trailer towing and method for configuring the dual-purpose connecting system tractor

Abstract

The present invention provides a dual-purpose connection system tractor for full trailer towing that can connect to either a center axle connection system or a dolly connection system's Lunette eye, and that prevents the center axle connection system's Lunette eye from damaging the dolly connection system's pintle hook. [Solution] The dual-purpose connection system tractor 10 comprises a center axle type bellmouth coupling 12, a dolly type pintle hook 20, and a rear bumper 30 located at the lower rear end of the vehicle body. A center axle type lunette eye 16 can be selectively connected to the bellmouth coupling 12, and a dolly type lunette eye 18 can be selectively connected to the pintle hook 20. The rear bumper 30 is supported so as to be able to swing up and down and can be positioned at the lower rear end of the vehicle body. The bellmouth coupling 12 is mounted at the center of the vehicle body width direction of the cross member 14A, in front of the support position of the rear bumper 30 on the vehicle body. The pintle hook 20 is mounted at the center of the vehicle body width direction at the rear end of the tractor 10. The rear bumper 30 is attached to the tip of a swingable bumper arm 32, which is swingable between an upper limit swing position and a lower limit swing position. In the upper limit swing position, with the dolly-type lunette eye 18 not engaged with the pintle hook 20, the bumper arm 32 is at the same horizontal height as the horizontal arm portion of the lunette eye 18, and the rear end bumper 30 covers the rear side of the pintle hook 20. In the lower limit swing position, with the lunette eye 18 engaged with the pintle hook 20, the rear end bumper 30 is at a height that does not interfere with the lunette eye 18, and the height of the bellmouth coupling 12 is such that the lunette eye 16 engaged with it is lower than the bumper arm 32 in the horizontal position.

Description

Technical Field

[0001] This invention relates to a dual connection system tractor for full trailer towing and a method for configuring a dual connection system tractor.

Background Art

[0002] As connection methods between a full trailer and a tractor for towing it, there are a center axle method and a dolly method.

[0003] Conventionally, the dolly method with good maneuverability has been widely used, and the center axle method has been relatively less used. However, in recent years, due to a shortage of drivers, the center axle method with a large loading capacity is increasing. When a center axle method tractor returns to a logistics base, all trailers loaded with goods are of the dolly method, and there are often no center axle method trailers.

[0004] In recent years, a system that can be used for both of these different connection methods has been desired. However, it is difficult to mutually change between a center axle method tractor and a full trailer, and a dolly method tractor and a full trailer. There has been no dual connection system tractor that can be connected by either method.

[0005] Also, when searching J-PlatPat with the keywords "full trailer", "center axle", and "dolly" under the AND condition, Patent Documents 1 and 2 were detected, but no invention regarding a dual connection system tractor was disclosed.

[0006] Here, a tractor and a full trailer using a conventional center axle method connection system are shown in FIG. Also, an example of a dolly method connection system is shown in FIG.

[0007] As shown in FIG. 16, in a center axle method tractor 1A, a tractor-side bell mouth coupling 5 is fixed to the rear and bottom of the tractor 1A.

[0008] The tractor-side bellmouth coupling 5 is supported by a connecting rod 6A at the front end of the trailer 2A's body, and the center axle type lunette eye 6 at the tip of the connecting rod 6A is engaged with the tractor-side bellmouth coupling 5 from the rear, thereby connecting the center axle type tractor 1A and trailer 2A.

[0009] In Figure 16, reference numeral 3 indicates the rear end swing bumper. When the center axle type Lunette Eye 6 is connected to the tractor-side bellmouth coupling 5, it is raised to the rear (retracted position). For example, when the center axle type tractor 1A is running alone, it swings downward around the swing axis 3B (operating position), and the rectangular cross-section rear end swing bumper 3 is lowered to the height where the connecting rod 6A was located. In Figure 16, reference numeral 9 indicates the rear wheel, and reference numeral 3A indicates the swing lever.

[0010] The rear-end swing bumper 3, in this operating position, prevents the rear-ending vehicle from getting stuck under the tractor in the event of a rear-end collision while the center-axle type tractor 1A is traveling alone.

[0011] As shown in Figure 17, the dolly connection system engages a dolly lunette eye 7 at the end of a connecting rod 7A, which is mounted protruding forward from the dolly trailer 2B, with a pintle hook 8 attached to the rear frame of the dolly tractor 1B.

[0012] Here, unlike the center axle system, the rear bumper of the tractor is a fixed rear bumper 4. The fixed rear bumper 4 is fixed to the side frame 1C of the dolly-type tractor 1B via a fixed arm 4A.

[0013] When considering a dual-purpose connection system tractor having the two connection methods described above, interference with the rear swing bumper or rear fixed bumper becomes a problem when connecting the center axle type Lunette eye from the dolly type tractor side to the center axle type tractor side bellmouth coupling.

[0014] In particular, when a pintle hook is not used in a dolly system, if the raised position of the rear end swing bumper is not brought close to the pintle hook, there is a high possibility of contact or collision between the pintle hook and the center axle type lunette eye. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Japanese Patent Publication No. 2002-200989 [Patent Document 2] Japanese Patent Publication No. 2002-120774 [Overview of the Initiative] [Problems that the invention aims to solve]

[0016] The present invention aims to provide a dual-purpose connection system tractor for full trailer towing and a method for configuring a dual-purpose connection system tractor that can avoid interference between the rear bumper and the lunette eye of the center axle system, as well as damage to the pintle hook caused by the lunette eye of the center axle system, for both center axle and dolly connection systems. [Means for solving the problem]

[0017] In other words, the present invention comprises a bellmouth coupling on the tractor side in a center axle connection system, a pintle hook on the tractor side in a dolly connection system, and a rear bumper that is long in the width direction of the vehicle body and is located below the rear end of the tractor body, wherein the bellmouth coupling can be selectively connected to a center axle type lunette eye on the full trailer side in a center axle connection system, and the pintle hook can be selectively connected to a dolly type lunette eye on the full trailer side in a dolly connection system. The rear bumper is pivotably supported at at least two locations in the width direction of the vehicle body by a pair of left and right side frames that extend in the longitudinal direction of the vehicle body at positions spaced apart in the width direction of the vehicle body at the rear of the tractor, and is positioned below the rear end of the side frames. The bell mouth coupling is attached to the center in the width direction of the vehicle body of a cross member stretched between the left and right side frames, at a position forward in the longitudinal direction of the vehicle body from the rear bumper support positions on the left and right side frames. The pintle hook is positioned at the rear end of the tractor. The rear end cross member is mounted horizontally in the width direction on the rear vertical plane at the center of the vehicle body width direction, and the rear end bumper is attached to the tip of a bumper arm that is pivotably supported on the side frame at its base pivot axis, and the bumper arm is pivotable between an upper limit pivot position and a lower limit pivot position, the upper limit pivot position is the position where the bumper arm is horizontal and at the same height as the horizontal arm portion of the lunette eye on the dolly-type connection system full trailer side when the lunette eye is not engaged with the pintle hook, and the lower limit The swing position is set to a height position in which the rear end bumper does not interfere with the lunette eye when the lunette eye is engaged with the pintle hook, and the bell mouth coupling is set to a height position such that when the bell mouth coupling is attached and the lunette eye on the center axle type full trailer side is engaged with it, the lunette eye is lower than the bumper arm in the horizontal position at the upper limit swing position. This dual-purpose connecting system tractor for full trailer towing solves the above problem. The inventor of this invention and all inventions dependent thereon is Hajime Tamura.

[0018] Furthermore, a dual-purpose connection system tractor configuration method that allows a lunette eye provided on the full trailer side of a dolly connection system to connect to a tractor for towing a full trailer, comprising a bellmouth coupling as part of a center axle connection system and a rear bumper that is long in the vehicle axis direction and supported by a pair of left and right side frames that extend in the longitudinal direction of the vehicle body at both sides in the width direction of the vehicle body at the rear of the tractor, and positioned below the rear end of the side frames, wherein the pintle hook in the dolly connection system is attached to the center in the width direction of the vehicle body on the rear vertical plane of the rear end cross member which is positioned horizontally in the width direction of the vehicle body at the rear end of the tractor, and the rear bumper is attached to the tip of a bumper arm that is pivotably supported by the side frame on a base pivot axis, and between an upper limit pivot position and a lower limit pivot position The above problems are solved by a dual-purpose connection system tractor configuration method characterized by the following: the system is swingable between the upper limit swing position, the bumper arm is positioned horizontally at the same height as the horizontal arm portion of the lunette eye when the lunette eye on the dolly-type connection system full trailer side is not engaged with the pintle hook, and the rear end bumper is positioned so as not to interfere with the lunette eye when the lunette eye is engaged with the pintle hook, and the bellmouth coupling is mounted such that when the bellmouth coupling is attached and the lunette eye on the center axle-type full trailer side is engaged with it, the lunette eye is lower than the horizontal bumper arm at the upper limit swing position. All inventors of this invention are Hajime Tamura.

[0019] Furthermore, the present invention is a tractor for a full trailer towing dual connection system, which is formed by attaching a bellmouth coupling in a center axle connection system and a pintle hook in a dolly connection system to the rear of the tractor. A lunette eye provided on the full trailer side in the center axle connection system is selectively connectable to the bellmouth coupling, and a lunette eye provided on the full trailer side in the dolly connection system is selectively connectable to the pintle hook. The inventor of this invention is Katsunao Suzuki.

Advantages of the Invention

[0020] Since the tractor for a full trailer towing dual connection system according to the present invention is configured as described above, in a tractor having a pintle hook in a dolly connection system, a tractor-side bellmouth coupling in a center axle connection system, and a swing bumper provided at the lower part of the rear end of the vehicle body, when the center axle type lunette eye is engaged with the bellmouth coupling and the rear bumper covers the rear of the pintle hook, when the tractor is reversed and the bellmouth coupling is brought close to the center axle type lunette eye, it has the effect of suppressing the center axle type lunette eye from contacting or colliding with the pintle hook and damaging it.

Brief Description of the Drawings

[0021] [Figure 1] [[ID=*15]]Side view showing the main part of a tractor for a full trailer towing dual connection system according to an embodiment of the present invention [Figure 2] [[ID=*18]]Rear view of the same tractor [Figure 3] [[ID=*21]]Plan view showing the main part of the same tractor [Figure 4] [[ID=*24]]Bottom view showing the main part of the same tractor [Figure 5] [[ID=*27]]Side view showing the main part of the same tractor during single vehicle running [Figure 6] [[ID=*30]]Rear view showing a partial cross-section of the main part of FIG. 5 as viewed from the rear of the vehicle body [Figure 7] Side view showing the main part of the tractor when connected to a dolly [Figure 8] Enlarged side view showing the main part of the tractor when connected to the center axle [Figure 9] Rear view showing a partial cross-section of the main part of the same tractor as viewed from the rear of the vehicle body [Figure 10] Enlarged side view showing the main part of FIG. 8 [Figure 11] Side view schematically showing the rear end bumper and fixing device in the same tractor [Figure 12] Plan view showing the same fixing device and the rear end bumper in the upper limit swing position [Figure 13] Perspective view showing the same fixing device in the lower limit swing position in an enlarged manner [Figure 14] Plan view showing an enlarged view of the lower half of FIG. 12 [Figure 15] Rear view showing the rear end bumper, bell mouth coupling, and dolly-type lunette eye on the side of the conventional tractor and full trailer as viewed from the rear of the vehicle body in FIG. 10 [Figure 16] Side view showing the main part of a conventional tractor and full trailer connected by a center axle method [Figure 17] Side view schematically showing the dolly-type lunette eye on the side of a conventional tractor and full trailer immediately before being connected by the dolly method

Mode for Carrying Out the Invention

[0022] [Example 1] The full-trailer towing dual-connection system tractor (hereinafter referred to as tractor) 10 according to this example, as shown in FIGS. 1 to 4, includes a tractor-side bell mouth coupling (hereinafter referred to as BMC) 12 in a center axle (hereinafter referred to as CA) method connection system, a tractor-side pintle hook 20 in a dolly method connection system, and a rear end bumper 30 disposed at a lower position at the rear end of the vehicle body.

[0023] The BMC12 is selectively connected to the CA-type lunette eye (hereinafter referred to as LE) 16 on the full trailer 11 side in the CA-type connection system, and the pintle hook 20 is selectively connected to the dolly-type LE 18 of the full trailer 11 in the dolly-type connection system.

[0024] As will be explained in more detail later, the BMC12 is attached to the cross member 14A, which is stretched between a pair of left and right side frames 14 near the rear end of the vehicle body of the dual-purpose connection system tractor 10, at the center position in the width direction of the vehicle body, as shown in Figure 5, and is capable of connecting the CA type LE16.

[0025] Here, "full trailer 11" is a general term that refers to both the center axle type full trailer 11A and the dolly type full trailer 11B.

[0026] In this embodiment 1, the rear bumper 30 at the rear end of the vehicle body in the center axle connection system has been modified from the conventional configuration in which it swings at a position forward of the rear end of the vehicle body as shown in Figure 17, to swing to a position that protrudes from the rear end of the vehicle body. It is swingable between the lower limit swing position shown by the solid line in Figure 1 and in Figure 5, respectively, and the upper limit swing position shown by the dashed line in Figure 1 and in Figure 9, respectively.

[0027] In detail, the rear bumper 30 is cylindrical in shape, and both ends are attached to the tips of bumper arms 32 that are pivotably supported by a pair of left and right side frames 14 that extend in the longitudinal direction of the vehicle body at both sides in the width direction of the vehicle body at the rear of the tractor 10, and the bumper arms 32 are such that the rear bumper 30 can pivot between the upper limit pivot position and the lower limit pivot position.

[0028] Here, the upper limit swing position is defined as the position where the D-type LE18 on the dolly-type full trailer 11B side is not engaged with the pintle hook 20, and the rear end bumper 30 is horizontal and at the same height as the horizontal bumper arm 32 and pintle hook 20 of the D-type LE18 (see Figures 8 and 10).

[0029] Furthermore, the lower limit of the swing position is set to a height position that does not interfere with the center axle system LE16 when the center axle system LE16 is engaged with the pintle hook 20, relative to the upper horizontal swing position of the bumper arm 32 (see Figure 7).

[0030] As detailed in Figures 3 and 5, the BMC12 is attached to the cross member 14A, which is stretched horizontally between the left and right side frames 14, at the center in the width direction of the vehicle body, at a position forward in the longitudinal direction of the vehicle body than the rear end bumper support position on the left and right side frames 14.

[0031] The pintle hook 20 is mounted at the center of the vehicle width direction on the rear vertical surface of the rear end of the rear end cross member 22A, which is positioned horizontally in the vehicle width direction at the rear end of the tractor 10 (see Figures 5 and 6).

[0032] With the center axle type LE16 on the center axle type full trailer 11A engaged with the BMC12, the center axle type LE16 and the connecting rod 17 are configured to be lower than the bumper arm 32, which is in a horizontal position at the upper limit swing position (see Figure 8).

[0033] Furthermore, as shown in Figure 7, the base pivot axis 32B of the bumper arm 32 is positioned at the same height as the connecting rod 18A of the dolly type LE18 which is engaged with the pintle hook 20, and the bumper arm 32 is designed so that when it reaches the upper limit pivot position, the rear end bumper 30 retracts behind the dolly type pintle hook 20.

[0034] More specifically, the rear bumper 30 is configured to be located on a horizontal line passing through the base pivot axis 32B of the bumper arm 32 when the bumper arm 32 is in its upper limit swing position (see the solid line portion in Figure 1 and Figure 10).

[0035] Furthermore, as shown in an enlarged view in Figure 12, the bumper arm 32 is configured to be fixed in place by the bumper arm fixing device 34 at the lower swing limit position shown by the dashed line and the upper swing limit position shown by the solid line in Figure 11 (schematic diagram).

[0036] More specifically, the bumper arm fixing device 34, as shown in Figures 12 and 13, comprises a pin insertion / removal lever 35, a pin 36 which can be inserted by the pin insertion / removal lever 35 into an upper position pin hole 36A or a lower position pin hole 36B formed in the mounting base plate 34A on the body side, and a compression coil spring 37 which biases the bumper arm 32 in the direction of the upper limit swing position.

[0037] The operator lifts the pin insertion / removal lever 35 in the direction of arrow A in Figure 12 to pull out the pin 36 from the upper pin hole 36A or the lower pin hole 36B, releasing the bumper arm 32 from its restraint and allowing the rear bumper 30 to be lifted or pushed down and swung.

[0038] When lifting the rear bumper 30, the assisting force from the restoration (extension) of the compression coil spring 37 reduces the burden on the worker. When pushing it down, a portion of gravity is absorbed by the compression of the compression coil spring 37, reducing the impact of the drop due to its own weight, thereby reducing the burden on the worker (driver).

[0039] After the bumper arm 32 has finished rising or lowering, inserting the pin 36 into the lower pin hole 36B or the upper pin hole 36A using the pin insertion / removal lever 35 fixes the bumper arm 32 in the lower limit swing position or the upper limit swing position.

[0040] Here, as described above, when the rear bumper 30 is in the upper limit swing position, as shown in Figures 8, 10, or 11, it covers the rear end surface of the pintle hook 20. Therefore, when the CA-type LE16 on the full trailer 11 side is engaged with the BMC12, it passes near the rear bumper 30, but vibrations or ground inclination can be prevented from causing contact or collision between the tip of the CA-type LE16 and the pintle hook 20. Even if contact occurs, since the surface of the rear bumper 30 is circular in its vertical cross-section, the CA-type LE16 can slide downwards even if it comes into contact with the rear bumper 30, thus avoiding impact and damage to the rear bumper 30. In this invention, the rear bumper 30 is not limited to having a circular vertical cross-sectional shape. When the bumper arm 32 is in the upper limit swing position, if the lower surface is a flat surface, a downwardly convex curved surface, or a downwardly convex semi-circular arc, the CA-type LE16 can slide even if it comes into contact with it.

[0041] [Example 2] Embodiment 2 is a dual-purpose connection system tractor configuration method that allows a tractor equipped with a center axle connection system to be connected to a Lunette Eye provided on the full trailer side in a dolly connection system.

[0042] This dual-purpose connection system tractor configuration method involves attaching the pintle hook 20 in the dolly-type connection system to the center of the vehicle width direction on the rear vertical surface of the rear end cross member 22A, which is positioned horizontally in the vehicle width direction at the rear end position of the tractor 1A having a center axle-type connection system. The rear end swing bumper, supported by a pair of left and right side frames 14 that extend in the longitudinal direction of the vehicle body at both sides in the vehicle width direction at the rear of the tractor, is a rear end bumper that is long in the vehicle width direction and positioned below the rear end of the side frame 14. The rear end bumper 30 is attached to the tip of a bumper arm 32 that is pivotably supported by the side frame 14 at its base pivot axis, and is configured to swing between an upper limit swing position and a lower limit swing position.

[0043] In detail, at the upper swing position, the bumper arm 32 is configured to be at the same horizontal height as the horizontal arm portion of the lunette eye 18, while the lunette eye 18 on the full trailer side of the dolly connection system is not engaged with the pintle hook 20.

[0044] Furthermore, at the lower limit of oscillation, the configuration is such that the rear end bumper 30 does not interfere with the lunette eye 18 while the lunette eye 18 is engaged with the pintle hook 20.

[0045] Furthermore, the bellmouth coupling 12 is configured such that, when the bellmouth coupling 12 is attached and the lunette eye 16 on the center axle type full trailer side is engaged with it, the lunette eye 16 is lower than the bumper arm 32 in the horizontal position at its upper limit swing position.

[0046] This method has the advantage of allowing for the easy and quick construction of a dual-purpose connecting system tractor, even for center-axle tractors which have limited towing capabilities.

[0047] Although the above embodiments all involve attaching a pintle hook to a tractor equipped with a center axle connection system, the present invention is not limited to this and can also be applied to configurations in which a bellmouth coupling is attached to a tractor equipped with a dolly connection system. [Explanation of symbols]

[0048] 1A... Center axle type tractor 1B... Dolly-type tractor 2A... Center axle trailer 2B... Dolly-type trailer 3…Rear end oscillating bumper 3A... Oscillating lever 3B…Swing axis 4… Rear end fixed bumper 4A... Fixed arm 5…Tractor-side bellmouth coupling 6... Center axle type Lunette eye 6A…Connecting rod 7... Dolly-type Lunette Eye 7A…Connecting rod 8... Pintle hook 8A…Connecting rod 9…Rear wheel 10… Dual-purpose connecting system tractor (tractor) 11…Full trailer 11A... Center axle type full trailer 11B... Dolly-type full trailer 12…Tractor-side bellmouth coupling (BMC) 12A…Mounting bracket 12B... Bellmouth support crossmember 14…Side frame 14A…Crossmember 16... Center axle type Lunette eye (CA type LE) 17...Connecting rod 18... Dolly-type Lunette Eye (D-type LE) 18A…Connecting rod 20... Pintle hook 22A...Rear end cross member 30... Rear bumper 32... Bumper Arm 32A...Bumper mounting base 32B... Base pivot axis 34... Bumper arm fixing device 34A…Mounting board 35...Pin insertion / removal lever 36... pin 36A…Upper position pin hole 36B…Lower position pin hole 37... Compression coil spring 40... Full trailer 42... Dolly-type Lunette Eye 44... Center axle type Lunette eye 50... Rear wheel arch 52... Rear wheel

Claims

1. The system comprises a bellmouth coupling on the tractor side in a center axle connection system, a pintle hook on the tractor side in a dolly connection system, and a rear bumper that is long in the axial direction and located below the rear end of the tractor's body. The bellmouth coupling is selectively capable of connecting to a center axle type lunette eye on the full trailer side in a center axle type connection system, and the pintle hook is selectively capable of connecting to a dolly type lunette eye on the full trailer side in a dolly type connection system. The rear bumper is pivotably supported at at least two locations in the width direction of the vehicle body by a pair of left and right side frames that extend in the longitudinal direction of the vehicle body at positions spaced apart in the width direction of the vehicle body at the rear of the tractor, and can be positioned below the rear end of the side frames. The bellmouth coupling is attached to the cross member stretched between the left and right side frames at the center in the width direction of the vehicle body, at a position forward in the longitudinal direction of the vehicle body from the rear end bumper support position on the left and right side frames. The pintle hook is attached to the rear vertical surface of the rear end cross member, which is positioned horizontally in the width direction of the vehicle body at the rear end of the tractor, at the center in the width direction of the vehicle body. The rear bumper is attached to the tip of a bumper arm that is pivotably supported by the side frame at its base pivot axis, and the bumper arm is pivotable between an upper limit pivot position and a lower limit pivot position. The aforementioned upper limit swing position is set to a position where the bumper arm is horizontal and at the same height as the horizontal arm portion of the lunette eye, when the lunette eye on the full trailer side of the dolly connection system is not engaged with the pintle hook. The lower limit swing position is set to a height position where the rear end bumper does not interfere with the lunette eye when the lunette eye is engaged with the pintle hook. The bellmouth coupling is characterized in that, when the bellmouth coupling is attached and the lunette eye on the center axle type full trailer is engaged with it, the lunette eye is lower than the bumper arm in the horizontal position at the upper limit swing position, making it a dual-purpose connecting system tractor for towing a full trailer.

2. In claim 1, A dual-purpose connecting system tractor for towing a full trailer, characterized in that the base pivot axis of the bumper arm is positioned at the same height as the arm portion of the dolly-type lunette eye that engages with the pintle hook, and the bumper arm is configured such that when it reaches the upper limit pivot position, the rear end bumper retracts to the rear side of the dolly-type pintle hook.

3. In claim 2, A dual-purpose connecting system tractor for towing a full trailer, characterized in that the rear end bumper is positioned on a horizontal line passing through the base end pivot axis of the bumper arm when the bumper arm is in its upper limit swing position.

4. In claim 3, A dual-purpose connecting system tractor for towing a full trailer, characterized in that the rear end bumper, when the bumper arm is in its upper limit swing position, has a lower surface of its vertical cross-sectional shape that is either a flat surface, a downwardly convex curved surface, or a downwardly convex semi-circular arc shape.

5. In any of claims 1 to 4, The rear end bumper is biased toward the upper limit swing position integrally with the bumper arm by a compression coil spring, and is configured to be biased toward the lower limit swing position by gravity against the biasing force of the compression coil spring. A dual-purpose connecting system tractor for towing a full trailer, characterized in that the bumper arm has a bumper arm fixing device that can be fixed to the side frame at the upper limit swing position or the lower limit swing position.

6. In any of claims 1 to 4, The pintle hook is mounted on a center-axle tractor equipped with a bellmouth coupling as part of a center-axle connection system, making it a dual-purpose connection system tractor for full trailer towing.

7. A dual-purpose connection system tractor configuration method that allows a Lunette Eye provided on the full trailer side of a dolly-type connection system to connect to a tractor for towing a full trailer, comprising a bellmouth coupling as part of a center axle connection system, and a pair of left and right side frames extending in the longitudinal direction of the vehicle body at both sides in the width direction of the vehicle body at the rear of the tractor, and a rear bumper that is long in the width direction of the vehicle body and positioned below the rear end of the side frames, In the dolly-type connection system, the pintle hook is attached to the rear vertical surface of the rear end cross member, which is positioned horizontally in the width direction of the vehicle body at the rear end of the tractor, at the center in the width direction of the vehicle body. The rear bumper is attached to the tip of a bumper arm that is pivotably supported by the side frame at its base pivot axis, and is capable of pivoting between an upper limit pivot position and a lower limit pivot position. At the upper limit swing position, the lunette eye on the full trailer side of the dolly connection system is not engaged with the pintle hook, and the bumper arm is positioned so that it is horizontal and at the same height as the horizontal arm portion of the lunette eye. At the lower limit swing position, the rear end bumper is positioned so that it does not interfere with the lunette eye while the lunette eye is engaged with the pintle hook. A dual-purpose connection system tractor configuration method characterized in that the bellmouth coupling is mounted such that, when the bellmouth coupling is attached and the lunette eye on the center axle type full trailer side is engaged with it, the lunette eye is lower than the bumper arm in the horizontal position at the upper limit swing position.

8. A dual-purpose connecting system tractor for towing a full trailer, characterized in that a bellmouth coupling in a center axle type connecting system and a pintle hook in a dolly type connecting system are attached to the rear of the tractor, and a lunette eye provided on the full trailer side of the center axle type connecting system can be selectively connected to the bellmouth coupling, and a lunette eye provided on the full trailer side of the dolly type connecting system can be selectively connected to the pintle hook.

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