JP4111840B2 - Transport vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transport vehicle that includes, for example, a loading platform that supports a load such as a mounted steel material and can change the height of the loading platform.
[0002]
[Prior art]
Conventionally, this type of transport vehicle is provided in a vehicle body so as to be movable up and down while maintaining a horizontal posture through a parallel link mechanism in which a loading platform is rotatable in the vertical direction. The parallel link mechanism is composed of four parallel links, and these parallel links are parallel to the front and rear portions of the outer surface of one of the left and right main frames in the vehicle body and the front and rear portions of the outer surface of the other main frame, respectively. The free end of each parallel link is connected to a front connection frame and a rear connection frame of the loading platform.
[0003]
The front and rear portions of the one main frame and the front and rear portions of the other main frame are provided with hydraulically driven lifting cylinder devices that individually rotate the parallel links in the vertical direction. The tip of the piston rod of the cylinder device for use is connected to the free end of each parallel link.
[0004]
According to this, since at least one parallel link is rotated by the lifting cylinder device, all the parallel links are rotated in the same direction and the loading platform is moved up and down in a horizontal posture. Can be moved up and down in a horizontal posture with a simple structure (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-129329 (page 3-6, FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional format, the parallel link mechanism constituted by four parallel links includes the front and rear portions of the outer surface of one of the left and right main frames in the vehicle body, and the front and rear portions of the outer surface of the other main frame. And is not provided at the center of the main frame in the front-rear direction. For this reason, when a load is placed on the loading platform via the pallet, the central portion of the pallet is easily bent, and the pallet and the loading platform are deformed, so that the load cannot be stably placed. is there.
[0007]
Here, in consideration of the above problems, when the interval in the front-rear direction of the parallel links provided on the front and rear portions of the outer side surfaces of the left and right main frames is narrowed, the parallel links will be disposed near the center portion, Since the support to the end of the loading platform becomes unstable, there is a risk of lack of stability depending on the loaded load. If a parallel link is added at the center of the mainframe in the front-rear direction, a complex tuning mechanism is required because the number of lifting cylinders increases, and in addition, a pump supply capacity for driving each lifting cylinder unit There is a problem of lack of.
[0008]
Therefore, the invention according to claim 1 of the present invention is a complicated method for placing a stable load without bending the central portion in the front-rear direction of the loading platform and for accurately synchronizing the timing of the lifting means and the operation. An object of the present invention is to provide a transport vehicle that does not require a tuning mechanism.
[0009]
[Means for Solving the Problems]
In order to achieve the above-described object, the transport vehicle according to the first aspect of the present invention is such that the load carrier supporting the load can be raised and lowered in the vertical direction via lifting means provided at the front and rear portions in the vehicle traveling direction. And a support means is provided in the middle part of the front raising / lowering means and the rear raising / lowering means. The support means comprises a cylinder device provided in a direction to support the cargo bed, and a contraction chamber of the cylinder device. And an oil tank that supplies and discharges hydraulic oil to and from the extension chamber, and a pilot check valve that controls the flow of hydraulic oil between the oil tank and the extension chamber. It is.
[0010]
Therefore, according to the first aspect of the present invention, when the loading platform is raised by the operation of the lifting and lowering means, the extension force acts on the cylinder device of the support means, and the cylinder device is extended in synchronization. As a result, the cylinder chamber's contraction chamber is to be negatively pressured. At this time, the pilot check valve is switched to a state that allows the flow of hydraulic oil from the oil tank to the extension chamber. The hydraulic oil in the oil tank automatically flows into the extension chamber due to the suction force. Such an extended posture of the cylinder device can be maintained by switching the pilot check valve so as to prevent the flow of hydraulic oil from the extension chamber to the oil tank. Therefore, when the load is transported, when the load acts on the center part in the front-rear direction of the bed, and when trying to bend the center, it is possible to maintain the extended state without shortening the cylinder device. The center part in the front-rear direction can be supported by the support means, and bending at the center part of the cargo bed can be prevented.
[0011]
When lowering the loading platform, with the pilot check valve switched so that hydraulic oil can flow bidirectionally between the oil tank and the extension chamber, the loading platform is lowered by the reverse operation of the lifting means, The hydraulic oil can automatically flow into the oil tank via the pilot check valve while the cylinder device is contracted by the downward force of the loading platform.
According to a second aspect of the present invention, there is provided the transport vehicle according to the first aspect, wherein the loading platform is arranged in a vertical direction with respect to the vehicle main body via lifting means provided at the front and rear portions of the vehicle main body. The cylinder device of the support means is provided between the vehicle main body and the cargo bed, and can be moved up and down.
Therefore, according to the second aspect of the present invention, the loading platform can be raised and lowered with respect to the vehicle main body by the operation of the lifting and lowering means. At this time, the lifting of the loading platform causes the support means provided between the vehicle main body and the loading platform. An extension force acts on the cylinder device.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Below, the 1st Embodiment of this invention is described based on FIGS.
As shown in FIG. 8, a transport vehicle 1 that transports a load 2 such as a steel material or a wire rod includes a trailer 4 </ b> A that includes a loading platform 3 </ b> A that supports the loaded load 2, and a towing vehicle 5 </ b> A that pulls the trailer 4 </ b> A. It consists of As shown in FIGS. 1 and 2, the towing vehicle 5 </ b> A is provided with a cab 6 and a pair of left and right drive wheels 8 that are rotationally driven by the engine 7.
[0013]
The vehicle body 10 of the trailer 4A includes a pair of left and right main frames 11a and 11b extending in the front-rear direction, end frames 12 and 13 connected between the front and rear ends of both main frames 11a and 11b, and both main frames 11a, And a plurality of connecting frames 14 connected to the intermediate portion of 11b. The vehicle body 10 of the trailer 4A is provided with a plurality of freely traveling wheels 15A.
[0014]
The rear part of the towing vehicle 5A and the front part of the vehicle body 10 of the trailer 4A are connected via a king pin 16 so as to be rotatable in the left-right direction around the vertical axis 17. A steering cylinder device 18 that changes the direction of the towing vehicle 5A relative to the trailer 4A to the left and right is distributed between the rear portion of the towing vehicle 5A and the front portion of the vehicle body 10 of the trailer 4A. Is provided.
[0015]
The loading platform 3 </ b> A includes a pair of left and right side frames 20 extending in the front-rear direction, and a plurality of front and rear connection frames 19 connected between the side frames 20. In addition, the width W1 of the loading platform 3A is formed wider than the width W2 of the vehicle body 10 of the trailer 4A.
[0016]
As shown in FIGS. 1 to 3, an elevating means 31 is provided at the front and rear portions of the vehicle body 10, and a support means 41 is provided at an intermediate portion between the front elevating means 31 and the rear elevating means 31. It has been.
[0017]
The lifting / lowering means 31 includes a hydraulically driven lifting / lowering cylinder device 32 and a link 34. The cylinder body of the lifting / lowering cylinder device 32 is rotatably attached to the front and rear portions of the outer surfaces of the left and right main frames 11a and 11b via pins in the vehicle width direction, and the tip of the piston rod 33 is connected to the connection frame 19. The free end of the link 34 is connected to the lower end of the link 34 via a pin so as to be relatively rotatable. Further, the lower end portion of the link 34 is respectively connected to the front and rear portions of the outer surface of the left and right main frames 11a in the vehicle body 10 and the front and rear portions of the outer surface of the other main frame 11b via pins in the vehicle width direction. The free end of the link 34 is attached to the lower part of the front connection frame 19 and the lower part of the rear connection frame 19 via pins, respectively, so as to be relatively rotatable. .
[0018]
As shown in FIGS. 3 and 7, the support means 41 includes a hydraulically driven support cylinder device 42, a contraction chamber 48 and an extension chamber 49 of the support cylinder device 42, a first pipe 46 and a second pipe 46. An oil tank 44 that supplies and discharges the hydraulic oil 50 through the pipe 47, and a pilot check valve 45 that controls the flow of the hydraulic oil 50 between the extension chamber 49 of the support cylinder device 42 and the oil tank 44, It is composed of
[0019]
That is, the first pipe 46 connected below the oil level of the hydraulic oil 50 stored in the oil tank 44 is connected to the contraction chamber 48, and the second pipe 47 allows the flow of the hydraulic oil 50 in one direction. Are connected to an extension chamber 49 via a pilot check valve 45 that can be switched between and bidirectionally. Further, the cylinder body of the support cylinder device 42 is provided at a central portion of the outer surface of the left and right main frames 11a and 11b, and the tip of the piston rod 43 of the support cylinder device 42 is located at the center of the cargo bed 3A. It is attached to the lower part of the connection frame 19 positioned in the section via a pin in the vehicle width direction so as to be relatively rotatable.
[0020]
When transporting the load 2, a pallet 21 is used as shown in FIGS. The pallet 21 has a front portion formed in a gate shape, and has a hollow portion 22 into which the trailer 4A can be inserted and removed from the front-rear direction. Further, on the upper surface of the pallet 21, a gate-shaped holding frame 23 that prevents the loaded load 2 from collapsing in the lateral direction is detachably installed. Furthermore, the front end of the pallet 21 is provided with a stopper body 24 that engages with the front surface of the loading platform 3A to prevent the rearward movement of the pallet 21 on the loading platform 3A.
[0021]
Hereinafter, the operation of the first embodiment will be described.
When the load 2 is transported by the transport vehicle 1, the load 2 is loaded on the pallet 21 using a dedicated crane or the like, and the holding frame 23 is attached to the pallet 21 to prevent the load 2 from collapsing to the left and right sides. To do.
[0022]
Then, as shown by the phantom line in FIG. 3, the transport vehicle 1 is moved backward with the loading platform 3 </ b> A lowered, and the trailer 4 </ b> A is inserted into the hollow portion 22 of the pallet 21 as shown in FIG. 5. Thereafter, as shown by the solid line in FIG. 3, by extending the piston rod 33 of the lifting cylinder device 32, the link 34 of the lifting means 31 is rotated synchronously upward, and the loading platform 3A remains in a horizontal posture. Ascending from the lower limit position P2 to the load support position P1. Thereby, as shown in FIGS. 6 and 8, the load 2 is supported on the loading platform 3 </ b> A via the pallet 21.
In this way, when the loading platform 3A rises due to the extension of the piston rod 33 of the lifting cylinder device 32, an extension force acts on the supporting cylinder device 42 of the supporting means 41 provided between the vehicle body 10 and the loading platform 3A. Then, it tries to extend the piston rod 43 synchronously. As a result, the contraction chamber 48 is to be negatively pressured. At this time, the pilot check valve 45 is switched to a state allowing the flow of the hydraulic oil 50 from the oil tank 44 to the extension chamber 49. The hydraulic oil 50 in the oil tank 44 automatically flows to the extension chamber 49 via the second pipe 47 by the suction force of the negative pressure described above. When the loading platform 3A reaches the ascending limit, the supporting cylinder device 42 extends and is positioned vertically as shown by the solid line in FIG.
Such an extended posture of the supporting cylinder device 42 can be maintained by switching the pilot check valve 45 so as to prevent the flow of the hydraulic oil 50 from the extension chamber 49 to the oil tank 44. Accordingly, when the load 2 is transported, when a load acts on the center portion in the front-rear direction of the loading platform 3A and the center portion is bent, the piston rod 43 of the supporting cylinder device 42 is not shortened. Since the center part in the front-rear direction of the cargo bed 3A can be supported by the support means 41, it is possible to prevent the pallet 21 and the center part of the cargo bed 3A from being bent. In this way, the load 2 is transported by running the transport vehicle 1 with the load 2 supported by the loading platform 3A via the pallet 21. At this time, as shown in FIG. 8, since the stopper body 24 of the pallet 21 is engaged with the front surface of the loading platform 3A, the pallet 21 can be prevented from shifting backward on the loading platform 3A during transportation.
[0023]
When unloading the load 2 from the trailer 4A, the piston rod 33 of the lift cylinder device 32 is shortened and the oil tank 44 and the extension chamber 49 are connected as shown by the phantom line in FIG. The pilot check valve 45 is switched so that the hydraulic oil 50 can flow bidirectionally through the second pipe 47, and the piston rod 43 of the support cylinder device 42 is shortened by the descending force of the loading platform 3A. The hydraulic oil 50 can automatically flow into the oil tank 44 from the extension chamber 49 via 45. Accordingly, the cargo bed 3A is lowered from the load support position P1 to the lower limit position P2 while being in a horizontal posture, and is supported by the vehicle body 10. Then, as shown in FIG. 5, the pallet 21 is landed, the load 2 is unloaded via the pallet 21, and then the transport vehicle 1 is moved forward to remove the trailer 4 </ b> A from the hollow portion 22 of the pallet 21.
[0024]
Next, a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 9, a plurality of free-wheeling traveling wheels 15 </ b> B are provided on the front and rear portions of the loading platform 3 </ b> B via lifting / lowering means 51, and a plurality of traveling wheels 15 </ b> B are disposed on the middle portion of the loading platform 3 </ b> B via support means 61. A freely traveling wheel 15B is provided, and a front end portion of the loading platform 3B is connected to a guide body 58 via a guided body 57 that is movable up and down.
[0025]
The elevating means 51 rotates the upper link 54 fixed to the loading platform 3B, the lower link 55 that is rotatable in the vertical direction with respect to the upper link 54 through the shaft in the vehicle width direction, and the lower link 55 in the vertical direction. The lifting / lowering cylinder device 52 is moved, and the piston rod 53 of the lifting / lowering cylinder device 52 is attached to an intermediate portion of the upper link 54 via a pin. It is attached to the intermediate part of the side link 55 via a pin.
[0026]
The support means 61 rotates the upper link 66 fixed to the loading platform 3B, the lower link 67 that can rotate in the vertical direction with respect to the upper link 66 through the shaft in the vehicle width direction, and the lower link 67 in the vertical direction. The supporting cylinder device 62, the oil tank 64, the pilot check valve 65, and the like to be moved are configured. The piston rod 63 of the supporting cylinder device 62 is attached to an intermediate portion of the upper link 66 via a pin, and is used for supporting. The cylinder body of the cylinder device 62 is attached to an intermediate portion of the lower link 67 via a pin.
[0027]
The operation in the second embodiment will be described below.
The raising of the loading platform 3 </ b> B extends the piston rod 53 of the lifting / lowering cylinder device 52 in the lifting / lowering means 51 and opens the upper link 54 and the lower link 55. As a result, the front and rear lower links 55 rotate in synchronization downward to raise the loading platform 3B from the lower limit position P2 to the load support position P1. As the loading platform 3B is raised in this way, an extension force acts on the support cylinder device 62, and the piston rod 63 of the support cylinder device 62 is extended in synchronization, thereby the first embodiment described above. In the same manner as the embodiment, the center portion in the front-rear direction of the loading platform 3B can be supported.
[0028]
Further, the lowering of the loading platform 3B shortens the piston rod 53 of the lifting cylinder device 52 in the lifting means 51 and closes the upper link 54 and the lower link 55. As a result, the front and rear lower links 55 rotate in synchronization with each other to lower the cargo bed 3B from the load support position P1 to the lower limit position P2. At this time, the pilot check valve 65 is switched between the oil tank 64 and the extension chamber of the support cylinder device 62 so that the hydraulic oil can flow in both directions, so that the support force is lowered by the lowering force of the cargo bed 3B. The piston rod 63 of the cylinder device 62 is shortened.
[0029]
Next, a third embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 10, a mast 74 having a front lifting / lowering means 71 is provided at the front of the standing part of the loading platform 3 </ b> C.
[0030]
A wheel joint device 87 is connected to the intermediate portion of the loading platform 3C via a support means 81, and the wheel joint device 87 is provided with a plurality of free running wheels 15C in the vehicle traveling direction.
[0031]
A wheel joint device 95 is connected to the rear portion of the loading platform 3C via a rear lifting / lowering means 91, and the wheel joint device 95 is provided with a plurality of free running wheels 15C in the vehicle traveling direction.
[0032]
The front elevating / lowering means 71 includes a bracket 75 provided at an upright portion of the loading platform 3 </ b> C and a front elevating / lowering cylinder device 72 provided between the bracket 75 and the mast 74. Here, the piston rod 73 of the front lifting cylinder device 72 is attached to the bracket 75 via a pin, and the cylinder body of the front lifting cylinder device 72 is attached to the mast 74 via a pin. Yes.
[0033]
The support means 81 includes a link 86 that is rotatable up and down with respect to the loading platform 3C via an axis in the vehicle width direction, a supporting cylinder device 82 that rotates the link 86 up and down with respect to the loading platform 3C, and an oil tank. 84, a pilot check valve 85, and the like. The upper end portion of the link 86 is rotatably attached to the loading platform 3C via a pin, and the lower end portion of the link 86 is connected to the intermediate portion of the wheel coupling device 87 via a pin. Attached. The cylinder body of the support cylinder device 82 is attached to the loading platform 3C via a pin, and the piston rod 83 of the support cylinder device 82 is attached to the intermediate portion of the link 86 via a pin.
The rear lifting / lowering means 91 includes a link 94 that is rotatable in the vertical direction with respect to the loading platform 3C via an axis in the vehicle width direction, and a rear lifting / lowering cylinder device 92 that rotates the link 94 in the vertical direction with respect to the loading platform 3C. The upper end portion of the link 94 is rotatably attached to the loading platform 3C via a pin, and the lower end portion of the link 94 is attached to an intermediate portion of the wheel coupling device 95 via a pin. The cylinder body of the rear elevating cylinder device 92 is attached to the loading platform 3C via a pin, and the piston rod 93 of the rear elevating cylinder device 92 is attached to the intermediate portion of the link 94 via a pin.
[0034]
The operation in the above third embodiment will be described below.
The lift of the loading platform 3C extends the piston rod 73 of the front lifting cylinder device 72 in the front lifting means 71 to give a lifting force to the loading platform 3C, and the piston of the rear lifting cylinder device 92 in the rear lifting means 91. The rod 93 is extended to swing the link 94 downward with respect to the loading platform 3C. Thereby, the loading platform 3C is raised from the lower limit position P2 to the load support position P1. By raising the loading platform 3C in this way, the link 86 is also swung downward in synchronism, an extension force acts on the supporting cylinder device 82, and the piston rod 83 of the supporting cylinder device 82 is synchronized. Thus, the central portion in the front-rear direction of the loading platform 3C can be supported in the same manner as in the first embodiment described above.
[0035]
Further, the lowering of the loading platform 3C shortens the piston rod 73 of the front lifting cylinder device 72 in the front lifting means 71 to apply a lowering force to the 3C, and the rear lifting mechanism 91 has a lower lifting cylinder device 92. The piston rod 93 is shortened, and the link 94 is swung upward with respect to the loading platform 3C. Thereby, the loading platform 3C is lowered from the lower limit position P2 to the load support position P1, and the link 86 is also swung in synchronization with the upper side. At this time, the pilot check valve 85 is switched between the oil tank 84 and the extension chamber of the support cylinder device 82 so that the hydraulic oil can flow in both directions, thereby supporting the load by the downward force of the loading platform 3C. The piston rod 83 of the cylinder device 82 is shortened.
[0036]
In each of the above embodiments, for example, as shown in FIG. 1, the transport vehicle 1 includes a trailer 4A provided with a loading platform 3A and a towing vehicle 5A that pulls the trailer 4A. It may be a self-propelled truck provided.
[0037]
In each of the above-described embodiments, as an example, a hydraulically driven cylinder device is used for the lifting cylinder device and the supporting cylinder device. In each of the above-described embodiments, the support means is arranged one by one in the intermediate portion between the front raising / lowering means and the rear raising / lowering means. However, a plurality of sets may be arranged.
[0038]
【The invention's effect】
According to claim 1 of the present invention described above, by providing support means in the direction of supporting the loading platform and supporting the central portion of the loading platform, it is possible to avoid the bending of the central portion of the loading platform, The load can be stably placed in the long term. Moreover, since the raising / lowering means and the operation timing can be automatically and accurately synchronized, a transport vehicle including a supporting means for supporting the central portion of the cargo bed can be provided without requiring a complicated synchronization mechanism.
[0039]
According to the second aspect of the present invention, the loading platform can be lifted and lowered with respect to the vehicle body by the operation of the lifting means, and at this time, the support provided between the vehicle body and the loading platform is raised by the lifting of the loading platform. An extension force can be applied to the cylinder device of the means.
[Brief description of the drawings]
FIG. 1 is a side view of a transport vehicle according to a first embodiment of the present invention.
FIG. 2 is a plan view of the transport vehicle.
FIG. 3 is a partially cutaway side view showing the up-and-down movement of the loading platform.
FIG. 4 is a rear view of the transport vehicle.
FIG. 5 is a rear view when the trailer of the transport vehicle is inserted into the hollow portion of the pallet.
FIG. 6 is a rear view when the load is supported by the loading platform via the pallet.
FIG. 7 is a structural diagram of the support means.
FIG. 8 is a side view when a load is supported by a loading platform via the pallet.
FIG. 9 is a side view of a transport vehicle according to a second embodiment of the present invention.
FIG. 10 is a side view of a transport vehicle according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transport vehicle 2 Load 3A Loading platform 10 Vehicle main body 31 Lifting means 32 Lifting cylinder device (lifting device)
34 Link 41 Support means 42 Cylinder device for support (cylinder device)
44 Oil tank 45 Pilot check valve 48 Contraction chamber 49 Extension chamber 50 Hydraulic oil P1 Load support position P2 Lower limit position

Claims (2)

The loading platform that supports the load can be raised and lowered in the vertical direction via lifting means provided at the front and rear portions in the vehicle traveling direction,
Support means is provided at an intermediate portion between the front lifting means and the rear lifting means. The support means includes a cylinder device provided in a direction to support the cargo bed, a contraction chamber of the cylinder device, and an extension device. A transport vehicle comprising: an oil tank that supplies and discharges hydraulic oil to and from a chamber; and a pilot check valve that controls a flow of hydraulic oil between the oil tank and the extension chamber. The loading platform can be raised and lowered in the vertical direction with respect to the vehicle body via lifting means provided at the front and rear portions of the vehicle body, and the cylinder device of the support means is provided between the vehicle body and the loading platform. The transport vehicle according to claim 1, wherein

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