JPH0740855A - Trailer - Google Patents

Abstract

(57) [Abstract] [Purpose] The centering device 52 controls the rotation of the pull rod 21 to ensure centering in a straight line direction, the number of parts is small, the structure is simple, and the assembly and adjustment are easy. To provide a trailer that can improve overall maintenance. [Structure] A trailer main body 1 is provided with a centering device 52 which controls the rotation of a pull rod 21 to constantly perform centering in a straight traveling direction. Aligning device
Reference numeral 52 has a vertical support shaft 53 attached to the trailer main body 1, and a pair of aligning arms arranged to face the support shaft 53.
The intermediate portion of 54 is pivotally supported. Pair of aligning arms 54
A compression spring 69 is disposed and supported between one ends of the. A centering roller 18 that is interlocked with the rotation of the pull rod 21 is engaged between the other ends of the pair of centering arms 54. A pair of aligning arms 54 are urged in a direction in which the aligning roller 18 is always held by the compression spring 69.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trailer and, for example, to a trailer connected to a towing vehicle such as a tractor at an airport or the like.

[0002]

2. Description of the Related Art Conventionally, as a trailer of this type, for example, as disclosed in Japanese Utility Model Publication No. 63-20617, a vertical connecting shaft is attached to a trailer body in which wheels are rotatably mounted on the left and right sides. A pull rod for steering the left and right wheels is horizontally rotatably supported on the connecting shaft, and a rotating body that is interlocked with the rotation of the pull rod is rotated around the connecting shaft. The shaft is freely supported, and the rotation of the pull bar is controlled by controlling the rotation of the pull rod between the left and right side parts of the rotating body and the both side parts of the intermediate frame arranged and fixed in the middle of the trailer body. A centering device consisting of a pair of left and right control bodies that are centered is provided. Each pair of control bodies of this centering device has a cylinder in the front-rear direction, and rods are slidable in the axial direction in the pair of cylinders. And a number of supports that support this rod. The spring and each successively adjacent in the axial direction of the rod is disposed structure is known.

[0003]

In the structure described in the above publication, the aligning device is composed of a rod and a pair of control bodies in which a large number of disc springs for urging and supporting the rod are sequentially adjacent to each other in the cylinder. The number of points is large and the structure is complicated, it takes a lot of time and effort to assemble a large number of disc springs in the cylinder, and the adjustment is troublesome.The disc spring is easily worn out, which is not preferable in improving the overall maintenance. There is a problem.

The present invention has been made in view of the above point, and the rotation of the pull rod can be controlled to surely align the pull rod in the straight traveling direction, and the number of parts is small. It is an object to provide a trailer that has a simple structure, is easy to assemble, and is easy to adjust, and can improve durability as compared with many disc springs, and can improve overall maintenance. It is a thing.

[0005]

According to a first aspect of the present invention, there is provided a trailer body in which wheels are rotatably mounted on the left and right sides, and the trailer body is horizontally rotatable by a vertical connecting shaft. A front and rear pull bar that is pivotally supported to steer the left and right wheels, and a centering device that is provided in the trailer body and that controls the rotation of the pull bar to constantly align the pull bar in a straight direction. The aligning device has a vertical support shaft attached to the trailer body, and is rotatable about an intermediate portion of a pair of aligning arms arranged opposite to the support shaft. A compression spring is disposed between one end of the pair of aligning arms and supported, and the other end of the pair of aligning arms is aligned with the rotation of the pull rod. The pair of aligning arms are arranged in a direction in which the aligning rollers are engaged and the aligning rollers are always sandwiched by the compression springs. It is intended to energized.

According to a second aspect of the present invention, in the trailer of the first aspect, one of the aligning arms of the aligning device rotatably supports a support having a guide hole, and the other end of the aligning arm. At one end of the aligning arm, a support rod inserted into the guide hole of the support is rotatably supported, and the adjuster is attached to the support rod so as to be adjustable in the axial direction. A compression spring is disposed and supported between the adjusting body and the support.

[0007]

According to the trailer of the present invention, the pair of aligning arms are biased by the compression spring of the aligning device about the support shaft, and the aligning rollers are provided at the other ends of the pair of aligning arms. It is sandwiched from both sides, and the aligning roller aligns and supports the pull rod in a state in which it is oriented in the straight direction. Further, since the pull rod body is supported in the straight traveling direction, the left and right wheels are steered by the pull rod body so as to run straight.

When the pull rod is steered to the right in the traveling direction, for example, the pull rod is horizontally rotated about the connecting shaft toward the right in the traveling direction, and the pull rod is moved to the right. The aligning roller is horizontally moved toward the right side in the traveling direction in association with the rotation, and the other end of the right aligning arm is pushed by the aligning roller toward the right side in the traveling direction.

The right-side centering arm is rotated around the support shaft, and one end of the right-side centering arm is horizontally moved toward the left side in the traveling direction, and the right-side centering arm is moved. While the compression spring is pressed and compressed at one end of the pull bar, the pull bar is horizontally rotated toward the right side in the traveling direction, so that the left and right wheels are rotated by the pull bar. Steered in the direction.

When the pull rod is steered from the right side to the left side in the traveling direction, the pull rod is horizontally rotated about the connecting shaft toward the left side in the traveling direction, and at the same time, the pull rod is moved. The aligning roller is horizontally moved toward the left side in the traveling direction in conjunction with the rotation, and one end of the aligning arm on the right side is automatically pushed by the repulsive force of the compressed compression spring. The right aligning arm is rotated by the spring about the support shaft, and one end of the right aligning arm is moved in the moving direction of the aligning roller while being engaged with the aligning roller.

When the pull rod is horizontally rotated toward the left side in the traveling direction, the right alignment arm is returned and rotated about the support shaft, and the pull rod is moved to the left and right wheels. Is steered in the turning direction of the pull rod, and the pull rod is steered in the straight direction, whereby the left and right wheels are automatically returned and steered to the straight traveling state.

In this way, the pair of centering arms are urged by the compression springs about the support shaft, and the centering rollers are again pinched from both sides by the other ends of the pair of centering arms. The pulling rod body is aligned and supported by the aligning roller in a state in which the pull rod body is directed in the straight direction.

According to a second aspect of the present invention, in the trailer of the first aspect, the right alignment arm is rotated around the support shaft, and one end of the right alignment arm is moved to the right side in the traveling direction. When moved horizontally toward the center, the support rod at one end of the right alignment arm is inserted into the guide hole formed in the support body at the one end of the left alignment arm, and the support rod is adjusted. While the compression spring is pushed and compressed by the body, the pull bar is horizontally rotated toward the right side in the traveling direction, so that the left and right wheels are moved in the pull bar direction by the pull bar. Steered towards.

When the pull rod is steered from the right side to the left side in the traveling direction, the support at one end of the right alignment arm is automatically pushed by the repulsive force of the compressed compression spring,
The support rod having this support is pulled out from the guide hole of the support of the left centering arm, and the right centering arm is rotated by the compression spring about the support shaft. The one end is moved in the moving direction of the aligning roller while being engaged with the aligning roller.

Therefore, the compression spring is expanded and contracted in the axial direction without being bent while being supported by the left and right support rods and the support body, and is attached to the compression spring and the pair of alignment arms urged by the compression spring. The pull rod is always aligned in the straight direction through the aligning roller.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a trailer body, which has a frame 2 formed in a substantially rectangular shape, on which a loading platform 3 having a large number of rollers (not shown) is provided. It is disposed and supported, and a container or the like is placed on the loading platform 3 so that it can be carried in and out freely.

Axles 4 which are long in the left-right direction are arranged and fixed in parallel to the front and rear ends of the frame 2, and both ends of the front and rear axles 4 are rotated by vertical support shafts 5. Free wheels 6 are rotatably supported in the horizontal direction. In addition, horizontally connected interlocking pieces 7 are integrally fixed to the support shafts 5 at both ends of the front and rear axles 4 in the front-rear direction.

A connecting frame 9 is integrally fixed to the left and right parallel intermediate frames 8 arranged and fixed to the intermediate portion of the frame 2 between front end portions and rear end portions thereof. . The front and rear connecting frames 9 have left and right connecting plates 10 which are fixed between the left and right intermediate frames 8 and are long in the vertical direction, and an upper surface plate 11 is integrally formed between upper end portions of the left and right connecting plates 10. The lower surface plate 12 is integrally fixed between the lower end portions of the left and right connecting plates 10, and is located between the upper surface plate 11 and the lower surface plate 12 and between the left and right connecting plates 10. The intermediate plate 13 is integrally fixed.

Next, in the front and rear connecting frames 9,
Vertically long connecting shafts 14 penetrating the upper plate 11, the lower plate 12 and the intermediate plate 13 are vertically arranged and supported, and the front and rear connecting shafts 14 have the upper plate 11 and the intermediate plate 13 respectively. The interlocking body (15) is located between and is rotatably supported in the horizontal direction. The front and rear interlocking bodies 15 have a rotating plate 16 that is supported on the connecting shaft 14 so as to be horizontally rotatable.
A centering roller 18 is rotatably supported in the horizontal direction by a roller shaft 17 on the upper end of the rotary plate 16, and an engaging plate 19 is vertically provided downward at the rear end of the rotating plate 16. A conical engagement hole 20 is formed in the middle of the engagement plate 19 in the left-right direction so as to penetrate in the front-rear direction.

Further, the front and rear connecting shafts 14 are positioned between the intermediate plate 13 and the lower plate 12 and are long in the front-rear direction.
21 is rotatably supported in the horizontal direction. The front and rear pulling rod bodies 21 each have a pulling rod 22 which is rotatably supported by the connecting shaft 14 in a horizontally rotatable manner and has a substantially rectangular cross section. Long guide holes 23 on both sides in the front-back direction
Are formed relative to each other.

An interlocking shaft 24 is movably inserted in the left and right guide holes 23 in the front-rear direction, and an engaging body 25 having a substantially rectangular cross section is connected to the interlocking shaft 24.
25 is fitted in a hollow portion 26 at the base end portion of the pull rod 22 so as to be able to advance and retract in the axial direction, and the interlocking member 15 is provided at the tip end portion of this engaging member 25.
A conical fitting protrusion 27 is formed integrally with the engaging hole 20 so as to be detachably fitted.

Further, on both left and right sides of the front and rear pulling rods 22, operating rods 29, which are long in the front-rear direction, are supported by supporting pieces 28 so as to be movable back and forth in the axial direction along the pulling rods 22. Both ends of the interlocking shaft 24 are connected to the base ends of the operating shafts 29, and the operating plates 30 are attached to the tip ends of the left and right operating rods 29.
Are integrally fixed to each other, and the left and right actuating plates 30 are formed with insertion holes 31 which are long in the front-rear direction.

Further, stoppers 32 are fixed to the middle portions of the left and right actuating rods 29, respectively, and are located between the stoppers 32 of the left and right actuating rods 29 and the left and right supporting pieces 28 to actuate the left and right actuating members. A coil spring 33 is wound around the rod 29. Then, the coil springs 33 urge the left and right actuating rods 29 in the axial direction toward the interlocking body 15, and the left and right actuating rods 29 push the engaging body 25 via the interlocking shaft 24.
The fitting protrusion 27 of the engaging body 25 is always fitted into the engaging hole 20 of the interlocking body 15.

Mounting frames 34 are respectively fixed to the front and rear ends of the intermediate frame 8 located below the front ends of the front and rear pull rods 22, and the front and rear mounting frames 34 have petals 35. Is rotatably supported in a vertical direction by a horizontal support shaft 36, and a horizontal interlocking pin 37 integrally projecting from the upper ends of the front and rear petals 35 is an operating plate of the front and rear pull rods 22. Each of them is movably inserted in an insertion hole 31 formed in 30. In addition, the front and rear petals 35 have a stepping rod.
38 and a stopper 39 are provided so as to project.

Then, as the front and rear petals 35 are stepped and rotated about the support shaft 36, the operating plate 30 and the left and right operating rods 29 are pulled by the respective interlocking pins 37 against the coil spring 33. It is interlocked and this front and rear left and right operating rod 29
The engaging projections 27 of the front and rear engaging bodies 25 are engaged with the engaging holes 20 of the interlocking body 15.
The pivot locks of the front and rear interlocking members 15 are released from the respective positions. The front and rear petals 35 that release the lock of the front and rear interlocking body 15 are supported by a lock lever 41 having an engagement step portion 40 that engages and disengages with the stopper 39 and a coil spring 42 that urges and supports the lock lever 41. It is supposed to be done.

Further, a connecting plate 44, which is long in the front-rear direction, is axially supported by an axial rod 43 on the upper ends of the front and rear pulling rods 22 so as to be vertically rotatable. Stick 22
A coil spring 45 stretched between and is always supported substantially horizontally. The front and rear drawbar bodies 21 are composed of the drawbar 22 and a connecting plate 44 connected to the tip of the drawbar 22.

Further, the front and rear pulling rods 22 are respectively connected with interlocking plates 46, which are horizontally disposed at substantially intermediate portions in the front and rear direction thereof, through supporting frames 47, and the front and rear interlocking members are interlocked with each other. Board 46
One end of a pair of left and right steering rods 48 is rotatably supported in the horizontal direction by a vertical support shaft 49 on the left and right ends of the front end of the front and rear ends of the pair of left and right steering rods 48. The front ends of the left and right interlocking pieces 7 are rotatably supported in the horizontal direction by support shafts 50, respectively. The front and rear wheels 6 are steered in the left and right directions of the front and rear left and right wheels 6 through the pair of left and right steering rods 48 in the front and rear pull rods 21.

Next, support frames 51 are horizontally fixed integrally to the front and rear ends of the left and right parallel intermediate frames 8, and the front and rear pull bar members 21 are attached to the front and rear support frames 51. A centering device 52 is provided for controlling the rotation of the front and rear pull rods 21 so as to always align the front and rear pull rods 21 in the straight traveling direction.

The front and rear aligning device 52 is a vertical support shaft which is positioned on an axis connecting the front and rear connecting shafts 14 and the aligning rollers 18 and is vertically supported on the front and rear support frames 51. An intermediate portion of a pair of left and right aligning arms 54, which are disposed so as to face each other, is rotatably supported on the front and rear support shafts 53, respectively. The pair of front and rear aligning arms 54 are formed in a substantially L shape, and the bent portion 55 has a front and rear support shaft 53.
Has a bearing portion 56 rotatably supported on the
The mounting pieces 58 in the front-rear direction are integrally spaced apart from each other in the vertical direction at one end portion, that is, the projecting end portion of the left and right arm portions 57 extending from the bending portion 55 in the front-rear direction. The aligning roller 18 is interveningly engaged between the other end of the holding arm portion 59, that is, between the protruding ends.

Further, of the pair of front and rear aligning arms 54, a support 61 having a guide hole 60 is provided between the mounting pieces 58 at the projecting end of one of the aligning arms 54, and the supporting body 61 has a vertical support shaft. A supporting rod 63 is rotatably supported by 62, and a supporting rod 63 is rotatably supported by a vertical supporting shaft 64 between the mounting pieces 58 at the protruding end of the other centering arm 54. The tip of the support rod 63 is inserted into the guide hole 60 of the support 61 so as to be able to move forward and backward, and the screw nut 65 formed at the base end of the support rod 63 is provided with an adjusting nut 66 as an adjusting body. It is screwed freely.

Further, between the flange 67 of the support 61 and the flange 68 of the adjusting nut 66, both ends of a compression spring 69 provided via the support rod 63 are engaged and supported. The compression spring 69 is formed of a wire having a rectangular cross section. Then, the front and rear compression springs 69 have one end portion of the pair of front and rear aligning arms 54 biased in the opening direction about the support shaft 53, and the other end clamping arm portions 59 are closed. The centering roller 18 is constantly clamped from both sides by the opposing clamping arm portions 59. Then, the tension of the compression spring 69 is adjusted by adjusting the forward / backward movement of the adjusting nut 66.

It should be noted that one end of the compression spring 69 is engaged with a flange of a collar that is movably mounted on the support rod 63, and the collar is attached to the support rod 63 by an adjustment nut 66 that is screwed movably on the support rod 63. It may be supported. The tension of the compression spring 69 is adjusted through the collar by adjusting the adjustment nut 66 forward and backward.

Further, brackets 70 are integrally fixed to the left and right portions of the front and rear support frames 51, which are positioned outside the front and rear aligning devices 52 in the left and right direction. A stopper 71 for supporting the arm portions 57 of the pair of front and rear aligning arms 54 is attached to each of the front and rear so as to be positionally adjustable.

Next, the operation of the above embodiment will be described.

A pair of aligning arms 54 opposed to each other by the compression springs 69 of the front and rear aligning devices 52 provided at the front and rear ends of the trailer body 1 have an arm portion 57 at one end centering on the support shaft 53. The aligning roller 18 is urged in the opening direction, and the aligning roller 18 is sandwiched from both sides by the sandwiching arm portion 59 at the other end of the pair of aligning arms 54, and the aligning roller 18 is interposed by the interlocking body 15. Pull bar
The pull rod 22 and the connecting plate 44 of 21 are aligned and supported in a state of being directed in a straight direction. Further, since the pull rod body 21 is supported in the straight traveling direction, the left and right wheels 6 are steered by the pull rod body 21 via the left and right steering rods 48 so as to travel straight.

Thus, the front and rear pulling rods 21 of the trailer main body 1 are aligned and supported by the front and rear pulling rods 21 so that they are always oriented straight. The front, rear, left and right wheels 6 are steered so as to travel straight. Then, in this state, the trailer body 1 has the pull rod 21 at the front end.
When the trailer body 1 is pulled, the trailer main body 1 is moved backward when the trailing rod body 21 is pulled.

When a plurality of trailers are connected to a tow vehicle such as a tractor to travel forward, the pull bar 21 at the front end of the first trailer body 1 is connected to the tow vehicle and the trailer is connected to the trailer. The pull bar 21 at the rear end of the main body 1 is connected to the pull bar 21 at the front end of the second trailer body 1, and the pull bar 21 at the rear end of the second trailer body 1 is connected to the third bar. The pull rods 21 at the front end of the trailer body 1 are connected, and then the same is connected.

Then, a plurality of trailers are towed by a towing vehicle to travel forward. At this time, the pulling rods 21 in front of and behind the plurality of trailer main bodies 1 are always moved straight by a centering device 52. Each of the pull rods is supported by being aligned and oriented.
At 21, the front, rear, left and right wheels 6 are steered toward straight running,
Therefore, the plurality of trailers travel forward without meandering.

Next, the pull rod at the front end of the trailer body 1
When 21, for example, is steered to the right in the traveling direction, the pull rod 21 is horizontally rotated about the connecting shaft 14 toward the right in the traveling direction, and the pull rod 22 of the pull rod 21 is rotated. The rotating plate 16 of the interlocking body 15 connected via the engaging body 25 is connected to the connecting shaft 14.
The centering roller 18 is horizontally rotated integrally with the pulling rod body 21, and the centering roller 18 is horizontally moved toward the right side in the traveling direction in association with the rotation of the rotating plate 16. The gripping arm portion 59 of the right aligning arm 54 is pushed toward the right side in the traveling direction.

The centering arm 54 on the right side of the support shaft 53
While being horizontally rotated around the center, the arm portion 57 at one end of the right alignment arm 54 is horizontally rotated toward the left side in the traveling direction, and the support rod 63 axially supported by the right arm portion 57 is supported. The arm part 57 of the centering arm 54 whose tip is on the left side
Is inserted deeply into the guide hole 60 of the support body 61 axially supported by the support rod 63, and the compression spring 69 is urged and compressed by the flange 68 of the adjusting nut 66 of the support rod 63. Body 21
Is steered rightward in the traveling direction around the connecting shaft 14, while the left and right wheels 6 are steered by the pull rod body 21 in the rotating direction of the pull rod body 21.

At this time, the arm portion 57 of the left aligning arm 54
Is supported by a stopper 71 arranged on the left side in the traveling direction, even if the compression spring 69 is pushed and compressed by the flange 68 of the adjusting nut 66 of the right centering arm 54, the compression spring 69 The centering arm 54 on the left side is not rotated about the support shaft 53, and the pull rod 21 is steered rightward in the traveling direction about the connecting shaft 14 against the compression spring 69.

When the pull rod 21 is steered to the left from the right in the traveling direction, the pull rod 21 is horizontally rotated about the connecting shaft 14 toward the left in the traveling direction. At the same time, the aligning roller 18 is horizontally moved to the left in the traveling direction in conjunction with the rotation of the pull rod 21, while the repulsive force of the compressed compression spring 69 causes the right aligning arm 54 to move. The adjustment nut 66 at one end is automatically pushed through the flange 68, and the support rod 63 having this adjustment nut 66 is gradually pulled out from the guide hole 60 of the support 61 of the left centering arm 54, and this compression is performed. Right alignment arm with spring 69
54 is rotated around the support shaft 53, and is moved in the moving direction of the aligning roller 18 while the sandwiching arm portion 59 of the right aligning arm 54 is engaged with the aligning roller 18.

When the pull rod 21 is horizontally rotated toward the left side in the traveling direction, the right aligning arm 54 is returned and rotated around the support shaft 53, and the pull rod 21 is rotated.
The left and right wheels 6 are steered in the rotating direction of the pull rod 21, and the repulsive force of the compression spring 69 causes the right centering arm 54 to move.
The arm part 57 of the stopper is arranged on the right side in the direction of travel.
By being abutted and supported by 71, the return rotation of the right alignment arm 54 is locked, the pull rod 21 is steered in the straight direction, and the left and right wheels 6 are moved by the pull rod 21. Steering is automatically performed to return to the straight running state.

Then, the pair of centering arms 54 are urged by the compression springs 69 around the support shaft 53, and the centering rollers are supported by the sandwiching arms 59 at the other ends of the pair of centering arms 54. 18 is again pinched from both sides, and the aligning roller 18 pulls the pull rod 21
Is aligned and supported in a state of being directed straight.

Next, the drawbar body at the front end of the trailer body 1
If 21 is steered to the left in the direction of travel,
21 is steered by the operation of the centering device 52 in the same manner as when it is steered to the right in the traveling direction, and the left and right wheels 6 are steered by the pull rod body 21 in the steering direction of the pull rod body 21. .

Next, the drawbar body at the front end of the trailer body 1
When it is not necessary to steer the left and right wheels 6 at 21, for example, when it is not necessary to align the operation of the pull rod body 21 at the aligning device 52, the pedal rod 35 of the petal 35 is depressed, 35 is rotated around the support shaft 36 and the petal 35
With the interlocking pins 37, the operating rods 29 on both sides of the pull rod 21 are pulled forward against the coil springs 33 provided on the pulling rods 21, and the interlocking shafts 24 are pulled by the operating rods 29 on both sides. To be done.

The engaging body 25 connected to the interlocking shaft 24
Is retracted into the hollow portion 26 of the pull rod 22, the fitting projection 27 of the engaging body 25 is disengaged from the engaging hole 20 of the interlocking body 15, and the pull rod 22 and the interlocking body
The lock with 15 is released. Therefore, the pull rod body 21 is rotated in the left-right direction about the connecting shaft 14, but the aligning device 52 does not participate in the rotation of the pull rod body 21.
21 can be rotated freely. By locking the petal 35 with the lock lever 41 and the coil spring 42 in a depressed state, the unlocked state of the pull rod 22 and the interlocking body 15 is maintained. Therefore, the pull rod 21, which is unlocked and freely rotatable, can easily perform the connecting work with the tow vehicle, for example.

Next, when a plurality of trailers are connected to a tow vehicle such as a tractor in the same manner as in the above case and the vehicle travels forward, each trailer is towed by the tow vehicle and travels along a curved portion to pull each trailer. When a predetermined turning angle is given to the rod body 21, each pulling rod body 21 is controlled by the centering action of the centering device 52 as in the case of the right steering and the left steering, and each of the connecting shafts 14 is controlled. The left and right wheels 6 are steered in the turning direction of the drawbar body 21 by the drawbar bodies 21, and the wheels 6 travel along a curved portion at a predetermined turning angle.

[0050]

According to the first aspect of the present invention, the trailer body is provided with an aligning device for controlling the rotation of the pull rod to align the pull rod in the straight direction at all times. It has a vertical support shaft attached to the trailer body, and rotatably supports the intermediate portion of a pair of aligning arms arranged opposite to the support shaft. A compression spring is disposed between one end of the pair of centering arms, and a centering roller that is interlocked with the rotation of the pull rod is engaged between the other ends of the pair of centering arms. Since the pair of aligning arms is urged in the direction in which the rollers are always sandwiched, it is possible to control the rotation of the pull rod body by the aligning device to reliably align the pull rod body in the straight traveling direction. This aligning device has a smaller number of parts and a simpler structure than the one that is composed of two control bodies in which a large number of disc springs are sequentially arranged adjacent to each other. It is easy to adjust with a simple, can improve the durability, can be totally improved maintenance.

According to the invention of claim 2, a support body having a guide hole is rotatably pivotally supported at one end of one of the aligning arms of the aligning device, and is supported at one end of the other aligning arm. Supports a support rod rotatably inserted in a guide hole of the support body so as to be rotatable, and an adjustment body is attached to the support rod so as to be adjustable in advance and retreat in the axial direction. Since the compression spring is disposed between and supported by, the spring force of the compression spring can be easily adjusted and set by adjusting the adjustment body in the axial direction along the support rod. It is possible to reliably prevent stable expansion and contraction and bending along the support rod.

[Brief description of drawings]

FIG. 1 is a plan view of a trailer showing an embodiment of the present invention.

FIG. 2 is a plan view in which a part of the aligning device is cut away.

FIG. 3 is a sectional view taken along line a-a of the above.

FIG. 4 is an enlarged sectional view of the same.

FIG. 5 is a sectional view taken along line 2b-b in FIG.

FIG. 6 is a plan view of the trailer showing a state in which the pull rod is steered.

FIG. 7 is a partially cutaway plan view showing an operating state of the above-mentioned pull rod and the aligning device.

FIG. 8 is a cross-sectional view showing a state in which the pull rod body is unlocked.

[Explanation of symbols]

 1 Trailer body 6 Wheel 14 Connecting shaft 18 Aligning roller 21 Drawbar body 52 Aligning device 53 Spindle 54 Aligning arm 60 Guide hole 61 Support 63 Support rod 66 Adjuster 69 Compression spring

Claims (2)

[Claims] 1. A trailer body having left and right wheels rotatably mounted thereon, and a front-back direction in which the left and right wheels are steered by a trailer body which is rotatably supported horizontally by a vertical connecting shaft. And a centering device that is provided in the trailer body and that controls the rotation of the pulling bar body to constantly align the pulling bar body in the straight-ahead direction, wherein the centering device is the trailer. It has a vertical support shaft attached to the main body, and rotatably supports the intermediate portion of a pair of aligning arms arranged opposite to this support shaft. A compression spring is arranged and supported between one ends, and a centering roller that is interlocked with the rotation of the pull rod is engaged between the other ends of the pair of centering arms. A trailer characterized by urging the pair of aligning arms in a direction in which the aligning roller is always sandwiched. 2. A support body having a guide hole is rotatably supported at one end of one of the aligning arms of the aligning device, and a guide hole of the support is provided at one end of the other aligning arm. A support rod that is inserted into and retracted from the inside is rotatably supported, and an adjusting body is attached to the supporting rod so that the adjusting body can be moved back and forth in the axial direction, and a compression spring is provided between the adjusting body and the support body. The trailer according to claim 1, wherein the trailer is disposed and supported.