JP3786572B2 - Forklift with traversing system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a forklift having a traversing system that can be switched to traverse traveling.
[0002]
[Prior art]
Conventionally, vehicles having a traversing system are found in large transport vehicles, some loaders, etc., and in forklifts, they are in reach type electric vehicles. However, counter-type engine-type forklifts can traverse in addition to normal work and do not have the same functions as side forks. In order to establish such a forklift, the front wheels, which are drive wheels, must be steered sideways.
[0003]
That is, the conventional forklift 1 shown by the solid line in FIG. 5 is provided with a pair of left and right front wheels (drive wheels) 3 at the front portion of the vehicle body 2 and a pair of left and right rear wheels (reversing wheels) 4 at the rear portion. A driver's seat 5 is provided above the front portion of the vehicle body 2. A mast 6 that can be expanded and contracted in the vertical direction is attached to the front end portion of the vehicle body 2 via a front axle 7 in the vehicle width direction so as to be rotatable in the front-rear direction, and a tilt cylinder 8 that rotates in the front-rear direction. It is provided between the vehicle body 2 and the mast 6.
[0004]
The mast 6 is composed of a pair of left and right outer frames 9 on the forklift 1 side and a pair of left and right inner frames 10 which are guided by the outer frame 9 and can be moved up and down, and between the outer frame 9 and the inner frame 10. A lift cylinder 11 is provided. Further, a lift bracket 12 that is guided to the inner frame 10 side and that can freely move up and down is provided, and a pair of left and right forks 14 is provided on the lift bracket 12 via a holding frame body 13.
[0005]
The driver's seat 5 is provided with a seat 15 and a handle 16 positioned in front of the seat 15, and above the head via a front pipe 17 and a rear pipe 18 erected from the main body 2 side. A guard 19 is provided. Further, a counterweight 20 is provided on the main body 2 behind the seat 15.
[0006]
In the conventional forklift 1 shown by the solid line in FIG. 5, since the mast 6 is positioned between the left and right front wheels 3, the front wheels 3 cannot be turned by 90 degrees, and therefore, traverse traveling is not possible. Absent. In order to run such a conventional forklift 1 in a traverse direction, as shown by the phantom line in FIG. 5, the mast 6 is attached in front of the front wheel 3 and the front wheel 3 is turned 90 degrees. Must.
[0007]
[Problems to be solved by the invention]
However, when the mast 6 is attached in front of the front wheel 3 as described above, the front overhang corresponding to the distance from the front axle 7 to the tip of the fork 14 is less than that in the conventional case (solid line in FIG. 5). There is a disadvantage that it becomes longer from L to L.
[0008]
Therefore, the invention according to claim 1 of the present invention is a traversing system in which the mast is positioned between the left and right front wheels, the front wheels can be turned 90 degrees, and the fork can have the required angle. The purpose is to provide a forklift that has it.
[0009]
[Means for Solving the Problems]
In order to achieve the above-described object, a forklift having a transverse system according to claim 1 of the present invention is provided on a vehicle body with a pair of left and right front wheels and a pair of left and right rear wheels capable of turning by 90 degrees. The mast is attached between the left and right front wheels on the front end side of the vehicle body via a mast connecting shaft positioned in the vehicle width direction so as to be rotatable in the front-rear direction and to be rotated in the front-rear direction. The device is provided between the vehicle body and the mast, and when the mast is rotated by the mast rotating device, the lower portion of the mast is configured to be moved to the non-interfering position of the front wheel. On the mast side, a fork is rotatably mounted in a vertical direction via a fork connecting shaft positioned in the vehicle width direction, and a fork rotation device that performs vertical rotation is provided between the mast side and the fork. Provided Is obtained is characterized in that there.
[0010]
Therefore, according to the first aspect of the present invention, the forklift is formed without a long front overhang because the mast is in an upright posture during normal running and its lower side is positioned between the left and right front wheels. Can do. When switching from normal running to transverse running, the mast is turned around the mast connecting shaft by the operation of the mast turning device, and the lower part is moved to the non-interfering position of the front wheel, Next, the front wheel is turned 90 degrees (turned sideways) with respect to the vehicle body. In that case, the conversion can be smoothly performed without any trouble because the lower part of the mast is moved to the non-interfering position.
[0011]
After performing this conversion, the mast can be rotated around the mast connecting shaft by a reverse operation of the mast rotating device to be in an upright posture, and the lower part thereof can be opposed to the side surface of the front wheel from the front. The forklift can be able to run in a transverse direction without increasing the front overhang.
[0012]
When the mast is rotated back and forth (tilt back and forth) around the mast connecting shaft by operating the mast rotating device, the fork rotating device is operated automatically or appropriately in conjunction with this operation. Thus, the fork can be rotated up and down around the fork connecting shaft, so that the fork can be at a required angle including a horizontal posture regardless of the mast's forward / backward rotation (tilt back and forth).
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS.
In the embodiment, the same or substantially the same components as those of the conventional example (FIG. 5) described above are denoted by the same reference numerals, and details thereof are omitted.
[0014]
1 is a forklift, 2 is a vehicle body, 3 is a front wheel, 4 is a rear wheel, 5 is a driver's seat, 6 is a mast, 8 is a tilt cylinder, 9 is an outer frame, 10 is an inner frame, 11 is a lift cylinder, 12 Is a lift bracket, 13 is a holding frame, 14 is a fork, 15 is a seat, 16 is a handle, 17 is a front pipe, 18 is a rear pipe, 19 is a head guard, and 20 is a counterweight.
[0015]
The pair of left and right front wheels 3 and the pair of left and right rear wheels 4 are provided so as to be able to turn 90 degrees with respect to the vehicle body 2 (can be turned sideways). The front wheel 3 is a drive wheel (a drive structure is not shown), and further includes an operating device (not shown) for turning 90 degrees. Further, the rear wheel 4 is a turning wheel and is provided with an operating device (not shown) for 90-degree turning or a caster type that performs follow-up turning.
[0016]
The mast 6 positioned on the front end side of the vehicle body 2 is positioned between the left and right front wheels 3 on the lower side in a standing posture. The mast 6 is attached to the vehicle body 2 so as to be rotatable in the front-rear direction via a mast connecting shaft 21 positioned above the front wheel 3 and in the vehicle width direction. The mast connecting shaft 21 is interposed between a bracket 22 from the vehicle body 2 side and a bracket 23 from the outer frame 9 side.
[0017]
A tilt cylinder 8, which is an example of a mast rotation device that rotates the mast 6 back and forth, is provided between the vehicle body 2 side and the outer frame 9 of the mast 6. When the mast 6 is rotated (tilted rearward) by the tilt cylinder 8, the lower part of the mast 6 is swung forward and moved to the non-interfering position of the front wheel 3. Yes.
[0018]
A fork rotating device for rotating the fork 14 up and down is mounted on the mast 6 side through a fork connecting shaft 24 positioned in the vehicle width direction. A hinge cylinder 26 as an example is provided between the mast 6 side and the fork 14. That is, a bracket 25 from the holding frame body 13 side is rotatably attached to the lift bracket 12 via the fork connecting shaft 24. The hinge cylinder 26 is provided between the lift bracket 12 and the bracket 25.
[0019]
The tilt cylinder 8 is connected to a contraction side supply / discharge path 31 and an extension side supply / discharge path 32 from the control valve 30. A contraction side supply / discharge path 33 is connected between the contraction side supply / discharge path 31 and the hinge cylinder 26, and an extension side supply / discharge path 35 is connected via a flow rate adjusting valve device 34. The extension-side supply / discharge path 32 is connected to the contraction-side supply / discharge path 33 via the flow rate adjusting valve device 36, the contraction-side supply path 37, and the shuttle valve device 38, and the extension-side discharge path 39 and the switching valve device. 40 is connected to the extension-side supply / discharge path 35.
[0020]
The operation in the above embodiment will be described below.
The solid line in FIG. 1 indicates the normal running time. At this time, the mast 6 is in a standing posture due to the contraction of the tilt cylinder 8, and the lower side thereof is positioned between the left and right front wheels 3. Therefore, the forklift 1 can be formed without increasing the front overhang.
[0021]
Such a forklift 1 can travel when an operator sitting on the seat 15 of the driver's seat 5 operates the handle 16. By operating the lift lever by operating the lift lever 11, the fork 14 can be moved up and down via the lift bracket 12 and the like, so that the intended fork work can be performed.
[0022]
When switching from normal running to transverse running, the transverse mode switch (not shown) is first operated to greatly extend the tilt cylinder 8. As the tilt cylinder 8 extends, the mast 6 is rotated (rearly tilted) around the mast connecting shaft 21 so that the upper portion thereof is rearward, and the lower portion of the mast 6 is shown as indicated by an imaginary line in FIG. Is moved forward from between the front wheels 3 to move to the non-interfering position of the front wheels 3.
[0023]
Next, a turning lever (not shown) is operated, and the front wheel 3 is turned 90 degrees (sideways) with respect to the vehicle body 2 as shown by the phantom line in FIG. Convert). At that time, the 90 degree turning of the front wheel 3 can be smoothly performed without any trouble because the lower part of the mast 6 is moved to the turning non-interfering position.
[0024]
After performing the desired conversion in this manner, the tilt cylinder 8 is contracted by feedback with a sensor. As a result, the mast 6 can be rotated around the mast connecting shaft 21, and the mast 6 can be placed in a standing posture as shown in FIG. Thus, the forklift 1 can enable traverse traveling without a long front overhang.
[0025]
As shown in FIG. 3B, the extension operation of the tilt cylinder 8 described above supplies pressure oil from the control valve 30 to the extension action chamber of the tilt cylinder 8 via the extension side supply / exhaust passage 32. Oil discharged from the contraction action chamber of the tilt cylinder 8 can be discharged by discharging to the control valve 30 side via the contraction side supply / discharge path 31.
[0026]
At that time, a part of the oil flowing through the contraction side supply / discharge path 31 is branched into the extension side supply / discharge path 35 by the flow rate adjustment by the flow rate adjustment valve device 34, and the hinge cylinder 26 is connected via the switching valve device 40. The oil that can be supplied to the extension chamber is discharged from the contraction chamber of the hinge cylinder 26 to the control valve 30 side through the shuttle valve device 38, the contraction side supply / discharge passage 33, and the contraction side supply / discharge passage 31. Can do. That is, when the tilt cylinder 8 is extended, the hinge cylinder 26 can be automatically extended in conjunction with it.
[0027]
Therefore, when the mast 6 is rotated around the mast connecting shaft 21 so that the lower part of the mast 6 is swung forward from between the front wheels 3 by the extension of the tilt cylinder 8, when FIG. As shown in FIG. 1A and the phantom line in FIG. 1, the holding frame 13 is rotated around the fork connecting shaft 24 so that the tip of the fork 14 moves downward by the extension of the hinge cylinder 26 (downward rotation). Move). As a result, the fork 14 can be maintained in a horizontal posture, and the load can be prevented from collapsing or falling.
[0028]
Further, in the posture in which the mast 6 stands up as shown by the solid line in FIG. 1, as shown in FIG. 4B, the pressure oil from the control valve 30 is supplied to the tilt cylinder via the contraction side supply / discharge passage 31. 8 is supplied to the contraction chamber of the tilt cylinder 8 and the oil discharged from the extension chamber of the tilt cylinder 8 is discharged to the control valve 30 side via the extension side supply / discharge passage 32 to cause the tilt cylinder 8 to contract. The mast 6 can be rotated (tilted forward) around the mast connecting shaft 21 so that the upper portion thereof is the front.
[0029]
At that time, part of the drained oil flowing through the extension side supply / discharge passage 32 is branched to the contraction side supply passage 37 by the flow rate adjustment by the flow rate adjustment valve device 36, and the hinge cylinder 26 contracts via the shuttle valve device 38. Oil supplied from the extension action chamber of the hinge cylinder 26 can be discharged to the control valve 30 side via the switching valve device 40, the extension side discharge path 39, and the extension side supply / discharge path 32. . That is, when the tilt cylinder 8 is contracted, the hinge cylinder 26 can be automatically contracted in conjunction with it.
[0030]
Therefore, when the mast 6 is rotated (tilted forward) around the mast connecting shaft 21 so that the lower portion of the mast 6 is pulled backward from between the front wheels 3 by contraction of the tilt cylinder 8, ( As shown in a), the contraction of the hinge cylinder 26 causes the holding frame body 13 to rotate (rotate upward) around the fork connecting shaft 24 so that the tip of the fork 14 moves upward. As a result, the fork 14 can be maintained in a horizontal posture, and the load can be prevented from collapsing or falling.
[0031]
In order to return the mast 6 rotated (rearly tilted) around the mast coupling shaft 21 as shown in FIG. 3A to the upright posture as shown by the solid line in FIG. 4 (b), the tilt cylinder 8 may be contracted, and the mast 6 rotated around the mast connecting shaft 21 as shown in FIG. 4 (a) is tilted. In order to return to the standing posture as shown by the solid line in FIG. 1, the tilt cylinder 8 may be extended in the state shown in FIG.
[0032]
In the above description, when the tilt cylinder 8 is extended or contracted, the hinge cylinder 26 is automatically extended or contracted in conjunction with this, but this is because the driver (operator) manually operates the switching valve device 40 as appropriate. By operating, when the tilt cylinder 8 is extended or contracted, the hinge cylinder 26 can be extended or contracted at any time, so that the fork 14 is required including a horizontal posture. Can be an angle.
[0033]
Further, as shown by the solid line in FIG. 1, when the mast 6 is in an upright posture, only the tilt cylinder 8 is operated to be extended or contracted by operating the tilt lever so that the mast 6 is moved around the mast connecting shaft 21. It can be rotated back and forth (tilt back and forth), so that the posture of the fork 13 can be changed in an inclined manner via the lift bracket 12 and the holding frame 13 or the like.
[0034]
In the above-described embodiment, the tilt cylinder 8 is shown as the mast turning device and the hinge cylinder 26 is shown as the fork turning device. However, these turning devices may be a screw drive type or a link type. .
[0035]
【The invention's effect】
According to the first aspect of the present invention, the forklift can be formed without a long front overhang during normal running. Switching from normal running to transverse running was accomplished by turning the mast around the mast connecting shaft (back tilting) by operating the mast turning device and moving the lower part to the non-interfering position of the front wheels. After that, the front wheel is turned 90 degrees with respect to the vehicle body (turned sideways), and the mast is turned around the mast connecting shaft by the reverse operation of the mast turning device to be in an upright posture. The forklift can smoothly perform the conversion without any trouble, and can be traversed without increasing the front overhang.
[0036]
Moreover, when the mast is rotated back and forth (tilt back and forth) around the mast connecting shaft by operating the mast rotating device, the fork rotating device is operated automatically or appropriately in conjunction with this. By doing so, the fork can be rotated up and down around the fork connecting shaft, so that the fork can be adjusted to the required angle, including the horizontal posture, regardless of the mast's front / rear rotation (tilt back and forth). The cargo can be prevented from collapsing or falling.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side view of a forklift having a traverse system during normal running, showing an example of an embodiment of the present invention.
FIG. 2 is a side view of the forklift having the traverse system when traversing.
FIG. 3A is a side view of the main part and FIG. 3B is a hydraulic circuit diagram at the time of rearward tilting of the mast in the forklift having the traverse system.
FIG. 4A is a side view of the main part and FIG. 4B is a hydraulic circuit diagram when the mast is tilted forward in the forklift having the traverse system.
FIG. 5 is a side view of a forklift showing a conventional example.
[Explanation of symbols]
1 Forklift 2 Car Body 3 Front Wheel 4 Rear Wheel 5 Driver's Seat 6 Mast 8 Tilt Cylinder (Rotation Drive Device)
9 Outer frame 10 Inner frame 11 Lift cylinder 12 Lift bracket 13 Holding frame 14 Fork 15 Seat 21 Mast connecting shaft 24 Fork connecting shaft 26 Hinge cylinder (fork rotating device)
30 Control valve 31 Contraction side supply / exhaust path 32 Extension side supply / exhaust path 33 Contraction side supply / exhaust path 34 Flow rate adjustment valve device 35 Extension side supply / exhaust path 36 Flow rate adjustment valve device 37 Contraction side supply path 38 Shuttle valve device 39 Extension side exhaust Path 40 switching valve device

Claims (1)

A pair of left and right front wheels and a pair of left and right rear wheels are provided on the vehicle body so that they can be turned by 90 degrees, and a mast connecting shaft positioned in the vehicle width direction between the left and right front wheels on the front end side of the vehicle body. The mast is pivotably mounted in the front-rear direction via a mast, and a mast rotation device for performing the front-rear rotation is provided between the vehicle body and the mast, and the mast is rotated by the mast rotation device. The lower part of the mast is configured to be moved to the non-interfering position of the front wheel, and the fork rotates up and down via a fork connecting shaft positioned in the vehicle width direction on the mast side. A forklift having a traversing system, characterized in that a fork rotation device that can be freely mounted and rotated up and down is provided between the mast side and the fork.

Images