JP2004142706A - Cargo receiving deck lifting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo receiving deck lifting device capable of control to gently stop a cargo at the uppermost position and the lowermost position with a simple constitution such as a detection device or the like. <P>SOLUTION: In the cargo receiving deck lifting device, a cargo receiving deck 6 is liftably provided between the ground and the loading space 15 located at a predetermined height from the ground by the telescopic movement of a lift cylinder 5 through a link mechanism. A dog 7 consisting of two detection pieces 71, 72 formed in a forked shape, is provided at the operation side of the link mechanism, and a detection device 8 is provided on a support member 10 supporting the link mechanism. The dog 7 and the detection device 8 are disposed so that the detection device 8 detects one detection piece 71 at the position just before the uppermost position of the cargo receiving deck 6, and the detection device detects the other detection piece 72 at the position just before the lowermost position of the cargo receiving deck 6, and the cargo receiving deck 6 is gently stopped at the uppermost position or the lowermost position by reducing the lifting/lowering speed of the cargo receiving deck 6 with the detection of the detection device 8 through a speed reduction means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, a loading tray lifting device provided at a rear portion of a loading truck of a freight vehicle such as a van type truck.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a loading tray elevating device, a lift arm having a base end rotatably connected to a vehicle body frame via a pin, and a loading tray rotatably connected to a distal end of the lift arm via a pin ( A gate), a lift cylinder rotatably connected to the vehicle body frame and the tip end of the lift arm via pins, respectively, and a pin disposed below the lift cylinder, A tilt cylinder that is rotatably connected via a tilt cylinder is known (for example, see Patent Document 1).
[0003]
In addition, there is provided a type in which the ascending / descending speed of the receiving cradle is slowed down to a gradual stop at the highest position and the lowest position at a position just before the receiving table rises and stops and a position before the receiving table touches the ground and descends and stops. (See, for example, Patent Document 2).
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 6-42909 (FIG. 4)
[Patent Document 2]
JP 2000-16149 A
[Problems to be solved by the invention]
However, in the apparatus that performs the gentle stop as described above, the first detector that detects that the vehicle has reached the position before the ascending stop position and the second detector that detects that the vehicle has reached the position before the descending stop position And two detectors are required. For this reason, there have been problems that two expensive detectors cause a rise in the entire apparatus, and that the structure is complicated and mounting work such as alignment is difficult.
[0006]
Also, in the above-described loading tray lifting device, there is a configuration in which the loading tray is rotated between a horizontal state in which the loading / unloading operation is moved upward and downward by a telescopic operation of the tilt cylinder and a standing state in which the loading tray is stored along the rear surface of the loading platform. In this case, if the loading stand is to be stopped slowly in the horizontal state and the upright state, the cost of the entire apparatus is increased by two expensive detectors as described above, and the structure becomes complicated, and mounting work such as alignment is performed. There was a problem that it was serious.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a cargo receiving platform capable of performing gentle stop control of a loading platform to a highest position and a lowest position with a simple configuration such as a detection device. It is an object of the present invention to provide a loading / unloading device capable of slowly stopping and controlling the loading / unloading device between a horizontal position and a standing position with a simple structure such as a lifting device and a detecting device.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, the loading tray lifting device is provided between the ground and the loading platform located at a predetermined height from the ground via a link mechanism by a retractable operation of a lift cylinder. In the loading / unloading device, a dog including two bifurcated detection pieces is provided on the link mechanism operating side, and a detection device is provided on a support side that supports the link mechanism. The detection device is arranged such that the detection device detects the one detection piece at a position immediately before the highest position of the load receiving table, and the detection device detects the other detection piece at a position before the most lower position of the load receiving table. , The lifting speed of the loading tray is reduced through the speed reduction means, and the loading tray is slowly stopped at the highest position and the lowest position.
[0009]
According to a second aspect of the invention, the load-carrying-table elevating device has a configuration in which the speed reducing means includes an electromagnetic proportional valve interposed in a pressure oil supply path to a lift cylinder.
[0010]
According to a third aspect of the invention, the load receiving platform elevating device is configured such that the speed reducing means reduces the amount of pressurized oil supplied from a pressurized oil supply source.
[0011]
According to a fourth aspect of the present invention, there is provided a loading tray elevating device, wherein a loading tray is provided between a ground and a loading platform located at a predetermined height from the ground via a link mechanism by a telescopic operation of a lift cylinder. A loading tray elevating device configured to be rotatable between a horizontal state in which the loading tray moves up and down by the expansion and contraction operation of the tilt cylinder and an upright state in which the loading tray rises along the rear surface of the loading tray. A dog consisting of two detection pieces formed in a shape is provided, and a detection device is provided on the side of the link mechanism that supports the rotation of the loading tray, and these dogs and the detection device are located at the horizontal front position of the loading tray. The detection device detects one of the detection pieces, and the detection device detects the other detection piece at a position just before the receiving stand rises. Slow down the rotational speed of those that are configured to slow stop the receiving platform in a horizontal position and an upright position.
[0012]
According to a fifth aspect of the invention, there is provided a lifting and lowering device for a loading tray, wherein the speed reduction means includes an electromagnetic proportional valve interposed in a pressure oil supply path to a lift cylinder.
[0013]
According to a sixth aspect of the invention, there is provided a lifting and lowering device for a loading tray, wherein the speed reduction means is configured to reduce a supply amount of pressurized oil from a pressurized oil supply source.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 to FIG. 4 show a schematic configuration of a loading tray elevating device of the present invention provided in a freight vehicle.
[0016]
In FIG. 1, a loading tray elevating device X is mounted via a support member 10 to a rear portion of a body frame formed of a main frame or the like of the freight vehicle 1. The loading tray lifting device X includes a tilt link 2, a lift arm 3, a tilt cylinder 4, a lifting cylinder 5 (only one of which is shown), and a loading tray 6, which are arranged in pairs on the left and right, respectively.
[0017]
The support member 10 includes a frame member 11 extending below the rear end of the vehicle body frame in the vehicle width direction, a pair of left and right fixed brackets 12 for fixing the frame member 11 to the rear end of the vehicle body frame, And support brackets 13 provided at both left and right positions of the material 11. Each of the support brackets 13 has opposing pieces 13a opposing each other in the vehicle width direction.
[0018]
A carrier 15 is mounted on the vehicle body frame.
[0019]
Each tilt link 2 is formed in a substantially U-shaped cross section that opens to the rear of the vehicle body frame, and extends in the vertical direction. The upper end (proximal end) of the tilt link 2 is located above the opposing piece 13 a of the support bracket 13 via a pin 21. It is rotatably connected, and the lower end side (tip side) swings in the direction of contacting and separating from the support member 10, that is, in the vehicle longitudinal direction. In this case, each tilt link 2 has a storage position (a position shown in FIG. 1) where the lower end side is stored in a contact state in the opposing piece 13a of the support bracket 13 and a disengagement position where the tilt link 2 is disengaged rearward from the inside of the opposing piece 13a. (The position shown in FIG. 3).
[0020]
Each lift arm 3 extends in the front-rear direction of the vehicle body, and its front end (base end) is rotatably connected to the upper end of the tilt link 2 via a pin 31. The rear end (front end) of each of the lift arms 3 is rotatably connected to upper and lower left and right positions of the load receiving table 6 via pins 32, respectively.
[0021]
Each tilt cylinder 4 is formed of a hydraulic cylinder, and is disposed below the lift arm 3 so as to extend in the vehicle longitudinal direction. The front end of each tilt cylinder 4 is rotatably connected via a pin 41 between a facing piece 13a outside the support bracket 13 and a bracket piece 16 facing the facing piece 13a from outside. I have. On the other hand, the rear end of each tilt cylinder 4 is rotatably connected via a pin 42 to the left and right ends of the lower end portion of the loading tray 6. In this case, each tilt cylinder 4 is laid out below the lift arm 3 at a position diagonally outward.
[0022]
Each of the lift cylinders 5 is composed of a hydraulic cylinder, and extends below the lift arm 3 in the vehicle longitudinal direction. The front end of each of the lift cylinders 5 is rotatably connected to the lower end of the tilt link 2 via a pin 51. The rear end of each of the lift cylinders 5 is rotatably connected via a pin 52 to a distal end of a substantially intermediate portion of the lift arm 3.
[0023]
The load receiving table 6 is moved to the highest position (the position shown in FIG. 1) by moving the lift cylinders 5 to extend to be substantially flush with the load table 15, while contracting each lift cylinder 5. By moving it, it is positioned at the lowest position (the position shown in FIG. 2) where it descends and comes into contact with the ground (ground) G.
[0024]
The loading table 6 has a substantially triangular cross-section when viewed from the side of the vehicle body, and has a mounting surface 61 (upper surface) which is horizontal (a state shown in FIGS. 1 and 2) and a rear end of the mounting surface 61. The (tip) is converted mutually into a downward tilt state (the state shown in FIG. 3) in which the (tip) comes into contact with the ground G.
[0025]
The loading table 6 is moved from the horizontal state (elevation operation state) shown in FIG. It is rotatable in an upright state (a state shown in FIG. 4) in which the mounting surface 61 stands up so as to cover the rear surface from behind. Conversely, the loading table 6 is rotatable from a standing state to a horizontal state at the highest position by a continuous falling operation by an operation switch.
[0026]
Next, the tilting operation and the undulating operation accompanying the lifting / lowering operation of the loading table 6 by the above-described loading table lifting apparatus X will be described with reference to FIGS. In this case, it is assumed that the receiving table 6 is positioned at the highest position (the position shown in FIG. 1).
[0027]
First, when the lowering switch (not shown) is turned on in lowering the load receiving table 6, the pressure oil in the non-rod side chamber 5a (see FIG. 6) of each lift cylinder 5 is actuated by the action of a load such as the weight of the load receiving table 6. Each of the lift cylinders 5 is gradually discharged and starts to contract, and the pins 51 at the front end of each of the lift cylinders 5, the pins 31 at the front end of each of the lift arms 3, and the pins 41 at the front end of each of the tilt cylinders 4 have their respective lift cylinders 5 and lifts The arm 3 and each tilt cylinder 4 are respectively turned downward.
[0028]
Thus, the loading tray 6 is lowered by rotating around the pins 52 at the rear ends of the lift cylinders 5 and the pins 32 at the rear ends of the lift arms 3 while being held in a horizontal state. At this time, since the load of the load receiving cradle is applied to each lift cylinder 5 when the lifting and lowering operation of the load receiving pedestal 6 is performed, each tilt link 2 is directed toward the detached position (the position shown in FIG. 3) behind the vehicle body. No force is applied and it is held in the storage position (the position shown in FIG. 1).
[0029]
Thereafter, when the loading tray 6 is positioned at the lowest position (the position shown in FIG. 2) where it comes into contact with the ground G, each tilt link 2 swings backward to the disengaged position (the position shown in FIG. 3), With the pin 42 at the rear end of the tilt cylinder 4 as a fulcrum, the rear end of the load receiving table 6 (the mounting surface 61) is tilted downward and automatically converted to a tilt state (the state shown in FIG. 3).
[0030]
In this case, the conversion of the loading tray 6 into the tilted state is performed by applying a downward load to the rear end of the loading tray 6 when the front end of the lower surface of the loading tray 6 descending while maintaining the horizontal state first contacts the ground G. It is done by doing. In other words, the pins 32 at the rear ends of the lift arms 3 are moved rearward of the vehicle body while the lift cylinders 5 are further contracted from the contact position of the load receiving table 6 by the load at the contact position of the load receiving table 6 to tilt each tilt link 2. This is because the state is converted to a state, whereby the rear end of the load receiving table 6 is tilted downward with the pin 42 at the rear end of the tilt cylinder 4 as a fulcrum.
[0031]
As described above, when the loading tray 6 is lowered to the contact position where the loading tray 6 contacts the ground G, each tilt link 2 automatically swings rearward of the vehicle body to the disengagement position due to a rotational moment of the pin 42 of the loading tray 6 or the like. The pin 32 at the rear end of the lift arm 3 also moves to the rear of the vehicle body in accordance with the swing of each tilt link 2, and the rear end of the loading table 6 is automatically moved downward with the pin 42 at the rear end of the tilt cylinder 4 as a fulcrum. Tilt can be performed, and loading and unloading of luggage can be performed smoothly.
[0032]
On the other hand, when the lift switch (not shown) is turned ON to raise the tilted cargo receiving table 6 from the ground position, pressure oil is supplied into the non-rod side chambers 5b (see FIG. 6) of the lift cylinders 5, and The lift cylinder 5 starts to extend and the rear end of the load receiving table 6 is tilted upward using the pin 42 at the rear end of the tilt cylinder 4 as a fulcrum, and is converted into a horizontal state, thereby moving the load receiving table 6 to the lowest position (load receiving position). Only the front end of the lower surface of the base 6 is in contact with the ground G).
[0033]
Then, by the extension movement of each lift cylinder 5 performed continuously as it is, each lift cylinder 5 around the pin 51 at the front end of each lift cylinder 5, the pin 31 at the front end of each lift arm 3, and the pin 41 at the front end of each tilt cylinder 4, Each lift arm 3 and each tilt cylinder 4 are rotated upward. As a result, the load receiving table 6 is raised by the rotation of the pins 52 at the rear end of each lift cylinder 5 and the pin 32 at the rear end of each lift arm 3 while being held in a horizontal state, and is substantially flush with the load table 15. In the highest position.
[0034]
In addition, when the loading stand 6 is raised at the highest position, when the standing operation is performed, the pressure oil is supplied into the opposite rod side chamber 4b (see FIG. 6) of each tilt cylinder 4, and each tilt cylinder 4 extends and moves. First, the rear end of the load receiving table 6 rotates upward with the pin 32 at the rear end of the lift arm 3 as a fulcrum, and the load receiving table 6 is turned from the horizontal state to the upright state (the state shown in FIG. 4) to be stored. I do. As described above, since the respective tilt cylinders 4 are extended and moved at the highest position to extend and rotate the load receiving table 6 around the pins 32 at the rear end of the lift arm 3, the load receiving table 6 is raised. The raising / lowering operation of the platform 6 can be easily performed by the extension movement of each tilt cylinder 4, and can be used as a door that covers the rear surface of the platform 15 of the freight vehicle 1 from the rear by raising the loading platform 6.
[0035]
By the way, in the loading tray lifting / lowering device X that moves up and down as described above, the loading tray 6 is decelerated at the position before the loading tray 6 reaches the highest position (the most upstream position) and slowly stopped at the highest position. At the position before the load receiving table 6 reaches the lowermost position (the position before the lowermost position), the load receiving table 6 is controlled so as to decelerate and slowly stop at the lowermost position.
[0036]
Specifically, a dog 7 composed of two bifurcated detection pieces 71 and 72 is integrally provided at the base end of the lift arm 3 serving as the link mechanism operating side, and supports the link mechanism. The detection device 8 is provided on the support member 10 side which is the support side. That is, the dog 7 is provided so as to rotate about the pin 31 in conjunction with the vertical movement of the lift arm 3.
[0037]
As shown schematically in FIG. 5, the dog 7 and the detecting device 8 detect the one detection piece 71 at a position before the receiving tray 6 reaches the highest position, and the detecting device 8 detects The other detection piece 72 is relatively arranged so that the detection device 8 detects the other detection piece 72 at a position before reaching the lowest position where it touches the ground.
[0038]
As the detection device 8, for example, a proximity switch is used, and each detection piece 71, 72 of the dog 7 detects each near position of the above-described loading tray 6 by approaching the detection device 8. I have.
[0039]
Then, based on the detection by the detecting device 8, a control device (not shown) operates the first electromagnetic proportional valve 98 shown in FIG.
[0040]
FIG. 6 shows a hydraulic circuit for extending and retracting the lift cylinder 5 and the tilt cylinder 4.
[0041]
In FIG. 6, P is a hydraulic pump operated by a motor M. The suction side of the hydraulic pump P is connected to the oil tank T, and the discharge side is connected to the opposite rod side chamber 5 b of each lift cylinder 5 by a first supply path 92 provided with a first switching valve 91.
[0042]
One end of a second supply path 94 provided with a second switching valve 93 is connected to the first supply path 92 closer to the hydraulic pump P than the first switching valve 91, and the other end of the second supply path 94 is connected to the first supply path 92. Each of the tilt cylinders 4 is connected to the opposite rod side chamber 4b. Further, a first return path 96 provided with a third switching valve 95 is connected to the second supply path 94 closer to the hydraulic pump P than the second switching valve 93, and the first return path 96 communicates with the oil tank T. Have been.
[0043]
The rod-side chambers 5 a and 4 a of each lift cylinder 5 and each tilt cylinder 4 are connected to the oil tank T through a second return path 97.
[0044]
The first to third switching valves 91, 93, and 95 are two-position switching valves, and are controlled by a control device (not shown) based on operation signals from operation switches such as an up switch and a down switch. , 93, and 95, the inflow path of the pressure oil is changed to control the ascending and descending operation of the loading tray 6.
[0045]
The first supply path 92 is provided with a first electromagnetic proportional valve 98 as a speed reducing means, and the second supply path 94 is provided with a second electromagnetic proportional valve 99 as a speed reducing means.
[0046]
Further, a fourth switching valve 100 is provided in a branch of the second supply path 94 which is communicated with the opposite rod side chamber 4b of each tilt cylinder 4.
[0047]
In FIG. 6, 101 is a relief valve, 102 is a throttle valve, and 103 is a flow control valve.
[0048]
Next, the slow stop control at the time of the lifting / lowering operation of the above-mentioned loading tray will be specifically described.
[0049]
First, when the lowering switch is turned on in a state where the loading tray 6 is at the highest position as shown in FIG. 1, the control device moves the first switching valve 91 and the third switching valve 95 to the left position in the state shown in FIG. And the first electromagnetic proportional valve 98 is gradually switched to the right position. At this time, the drive of the hydraulic pump P is stopped.
[0050]
Thereby, the pressure oil in the opposite rod side chamber 5b of each lift cylinder 5 is gradually returned to the oil tank T according to the opening degree of the first electromagnetic proportional valve 98. Therefore, the loading tray 6 starts to gradually descend at a speed corresponding to the degree of opening of the first electromagnetic proportional valve 98, and when the first electromagnetic proportional valve 98 is fully opened, the descending speed becomes constant and the loading tray 6 is moved as described above. Descend.
[0051]
Then, when the loading tray 6 reaches a position before the lowest position where the ground contacts the ground, the other detecting piece 72 of the dog 7 approaches the detecting device 8 and the detecting device 8 detects this. The control device gradually switches the first electromagnetic proportional valve 98 from the right position to the left position based on the detection signal from the detection device 8. By gradually switching the first electromagnetic proportional valve 98 to the left position and closing it in this manner, the pressure oil returned from the inside of the non-rod side chamber 5b of each lift cylinder 5 to the oil tank T is gradually throttled, and the cargo is accordingly received. The descending speed of the platform 6 gradually decreases from a position immediately before the lowest position, and the load receiving table 6 slowly reaches the lowest position and stops.
[0052]
As described above, after the loading table 6 starts to descend at a slow speed, it descends at a normal constant speed on the way, and when it reaches a position near the lowermost position, the lowering speed gradually decreases again to the lowest descending position. Stop at position. That is, the load receiving table 6 is controlled to be gently stopped from just before the lowermost position and is located at the lowermost position.
[0053]
Then, at the lowest position, the load receiving table 6 performs the tilt operation as described above.
[0054]
On the other hand, when raising the loading tray 6 from the lowest position to the highest position, the lift switch is turned ON. The control device drives the hydraulic pump P, switches the first switching valve 91 to the left position in the state of FIG. 6, and gradually switches the first electromagnetic proportional valve 98 to the right position.
[0055]
Thus, the pressure oil is gradually supplied to the opposite rod side chamber 5b of each lift cylinder 5 in accordance with the opening of the first proportional solenoid valve 98, and each lift cylinder 5 is extended. Accordingly, the loading tray 6 starts to gradually rise at a speed corresponding to the opening of the first electromagnetic proportional valve 98, and when the first electromagnetic proportional valve 98 is fully opened, the rising speed becomes constant, and the loading tray 6 is moved as described above. To rise.
[0056]
Then, when the loading tray 6 reaches the position before the highest position, one of the detection pieces 71 of the dog 7 approaches the detection device 8, and the detection device 8 detects this. The control device gradually switches the first electromagnetic proportional valve 98 from the right position to the left position based on the detection signal from the detection device 8. By gradually switching the first electromagnetic proportional valve 98 to the left position and closing it in this manner, the supply amount of the pressure oil to the non-rod side chamber 5b of each lift cylinder 5 is gradually reduced, and accordingly the load receiving table 6 The ascending speed gradually decreases from the position immediately before the highest position, and the loading tray 6 slowly reaches the highest position and stops.
[0057]
As described above, the loading table 6 starts rising at a slow speed, then rises at a normal constant speed on the way, and when reaching the vicinity of the highest position, the rising speed gradually decreases again to the highest level. Stop at position. That is, the load receiving table 6 is controlled to be gently stopped from a position immediately before the highest position, and is arranged at the highest position.
[0058]
Note that the above-described lifting operation of the loading table 6 includes an operation of returning the loading table 6 from the tilted state shown in FIG. 3 to the horizontal state shown in FIG. 2, and therefore, the lifting operation of the loading table 6 from the tilted state shown in FIG. It is preferable that the opening operation of the first electromagnetic proportional valve 98 is performed more slowly than when the lowering of the load receiving table 6 is started.
[0059]
As described above, the rotation position of the dog 7 is detected by the single detection device 8 and the load receiving table 6 is gently stopped at the highest position and the lowest position. As a result, the structure is simplified, mounting work such as positioning of the dog 7 and the detecting device 8 can be easily performed, and the manufacturing cost can be reduced. In addition, since the load receiving table 6 is gently stopped at the lowest position and the highest position, it is possible to minimize the impact generated on the load receiving table 6 when stopping at these positions. As a result, it is possible to prevent the load from dropping from the load receiving table 6 due to an impact, and to safely load and unload the load between the ground and the load platform 15.
[0060]
Here, the case where the dog 7 is provided at the base end of the lift arm 3 has been described. However, as long as the detection device 8 can detect the position of the load receiving table 6 at the most upstream position and at the most downward position, the dog 7 is It may be provided on any of the link mechanism operating sides.
[0061]
On the other hand, the operation of rotating the load receiving table 6 from the horizontal state shown in FIG. 1 to the upright state shown in FIG. 4 is performed by switching the first to fourth switching valves 91, 93, 95, and 100. Pressure oil can be supplied to the opposite rod side chamber 4b of the tilt cylinder 4 through the second supply path 94 to extend the tilt cylinder 4 to perform the operation. Conversely, the operation of disposing the load receiving table 6 from the upright state shown in FIG. 4 to the horizontal state shown in FIG. 1 is performed by supplying the pressurized oil in the non-rod side chamber 4 b of the tilt cylinder 4 to the second supply path 94 and the first return path 96. The tilt cylinder 4 is returned to the oil tank T, and the tilt cylinder 4 is retracted by the weight of the load receiving table 6 or the like.
[0062]
Also in this case, by controlling the opening and closing of the second electromagnetic proportional valve 99 in the same manner as the above-described first electromagnetic proportional valve 98, the loading tray 6 can be slowly stopped at each stop position.
[0063]
In this case, as shown in FIGS. 1 and 4, a dog 110 including two detection pieces 111 and 112 formed in a forked shape is provided on the rotation side of the loading tray, and the rotation of the loading tray 6 is controlled. A detection device 120 similar to the detection device 8 is provided on the supporting link mechanism side.
[0064]
Specifically, a dog 110 is rotatably provided on a pin 32 which is a center of rotation of the load receiving table 6, and a detection device 120 is provided at a distal end of the lift arm 3. The dog 110 is connected to the load receiving table 6 by a connecting member (not shown) so as to rotate in conjunction with the rotation operation of the load receiving table 6. That is, the dog 110 is provided so as to rotate about the pin 32 in conjunction with the rotation operation of the load receiving table 6.
[0065]
As shown in FIG. 4, the dog 110 and the detection device 120 detect the other detection piece 112 at a position before the load receiving table 6 reaches a standing state (a position just before standing). Are relatively arranged so that the detection device 120 detects the one detection piece 111 at a position (horizontal position) at which the horizontal position is reached.
[0066]
Next, a specific description will be given of the slow stop control when the loading tray is pivotally arranged between the upright state and the horizontal state.
[0067]
First, when the loading tray 6 is in the upright state as shown in FIG. 4, when the fall operation is performed, the control device switches the second switching valve 93 and the third switching valve 95 to the left position in the state shown in FIG. While switching the four-way switching valve 100 to the lower position, the second electromagnetic proportional valve 99 is gradually switched to the right position. At this time, the drive of the hydraulic pump P is stopped.
[0068]
Thereby, the pressure oil in the opposite rod side chamber 4b of each tilt cylinder 4 is gradually returned to the oil tank T according to the opening degree of the second electromagnetic proportional valve 99. Therefore, the loading table 6 starts to rotate from the standing state to the lower position gradually at a speed corresponding to the opening of the second electromagnetic proportional valve 99, and when the second electromagnetic proportional valve 99 is fully opened, the rotational speed becomes constant. As a result, the receiving table 6 rotates.
[0069]
Then, when the receiving table 6 reaches a position before the horizontal position, the one detecting piece 111 of the dog 110 approaches the detecting device 120, and the detecting device 120 detects this. The control device gradually switches the second solenoid proportional valve 99 from the right position to the left position based on the detection signal from the detection device 120. By gradually switching the second electromagnetic proportional valve 99 to the left position and closing it in this manner, the pressure oil returned from the inside of the non-rod side chamber 4b of each tilt cylinder 4 to the oil tank T is gradually squeezed. The rotation speed of the platform 6 gradually decreases from the above-mentioned near position, and the loading platform 6 slowly becomes horizontal and stops.
[0070]
As described above, after the loading table 6 starts rotating at a slow speed, it rotates at a normal constant speed on the way, and when it reaches near the horizontal state, the rotating speed gradually becomes slow again. Stop horizontally. That is, the load receiving table 6 is controlled to be gently stopped from near the horizontal state, and is arranged in the horizontal state.
[0071]
On the other hand, when the loading stand 6 is arranged from the horizontal state to the standing state, when the standing operation is performed, the control device drives the hydraulic pump P and switches the second switching valve 93 to the left position in the state of FIG. The second electromagnetic proportional valve 99 is gradually switched to the right position.
[0072]
As a result, pressure oil is gradually supplied to the opposite rod side chamber 4b of each tilt cylinder 4 in accordance with the opening of the second proportional solenoid valve 99, and each tilt cylinder 4 is extended. Accordingly, the loading table 6 starts to gradually rotate to the rising side at a speed corresponding to the opening of the second electromagnetic proportional valve 99, and when the second electromagnetic proportional valve 99 is fully opened, the rotation speed becomes constant and the loading table 6 is rotated. Rotates.
[0073]
Then, when the receiving table 6 reaches a position before the standing state, the other detecting piece 112 of the dog 110 approaches the detecting device 120, and the detecting device 120 detects this. The control device gradually switches the second solenoid proportional valve 99 from the right position to the left position based on the detection signal from the detection device 120. By gradually switching the second electromagnetic proportional valve 99 to the left position and closing it in this manner, the supply amount of the pressure oil to the opposite rod side chamber 4b of each tilt cylinder 4 is gradually reduced, and accordingly, the load receiving table 6 The rotation speed gradually decreases from the near position in the upright state, and the load receiving table 6 slowly enters the upright state and stops.
[0074]
As described above, the loading table 6 starts rotating from a horizontal state at a slow speed, then rotates at a normal constant speed on the way, and gradually reaches a position close to the standing state, whereupon the rotating speed gradually decreases again. It becomes a standing state. That is, the load receiving table 6 is controlled to be gently stopped from just before the standing state, and is arranged in the standing state.
[0075]
As described above, the rotation position of the dog 110 is detected by the single detection device 120 and the loading tray 6 is gently stopped in the upright state and the horizontal state. The structure is simplified, mounting work such as alignment of the dog 110 and the detection device 120 can be easily performed, and the manufacturing cost can be reduced. In addition, since the load receiving table 6 is gently stopped in the upright state and the horizontal state, it is possible to minimize the impact generated on the load receiving table 6 when stopping at these positions. Thereby, damage to the member due to impact can be prevented, durability can be improved, and the member can be arranged in a standing state and a horizontal state in a safe state.
[0076]
The location where the dog 110 and the detection device 120 are disposed is merely an example, and these may be provided at the optimal locations where the detection device 120 can detect the horizontal front position and the standing front position of the loading tray 6.
[0077]
In the present embodiment, the detection device using the proximity switch as the detection device 8 or 120 has been described. However, the detection device 8 or 120 is not limited thereto, and each detection piece 71 of the dog 7 such as a limit switch or a photo interrupter may be used. , 72, 111, and 112 can be detected.
[0078]
Further, the configuration of the receiving pallet lifting device X is not limited to the one described in the present embodiment, and may be a receiving pallet lifting device having a configuration in which the loading pallet 6 is raised and lowered via the link mechanism by the expansion and contraction operation of the lift cylinder 5. Just fine.
[0079]
In addition, the loading / unloading device elevating device X is not limited to the device provided on the freight vehicle, and may be provided on a facility for unloading cargo or the like between the ground and a carrier located at a predetermined height from the ground.
[0080]
Furthermore, the deceleration means is not limited to the first electromagnetic proportional valves 98, 98, and may be configured to reduce the amount of pressure oil supplied from the pressure oil supply source. In this case, the hydraulic oil supply source may control the driving amount of the motor M to reduce the hydraulic oil supply amount from the hydraulic pump P, or use a variable flow pump as the hydraulic pump P to supply the hydraulic oil. The amount may be reduced.
[0081]
【The invention's effect】
As described above, according to the loading / unloading device lifting / lowering device of the present invention, a dog including two bifurcated detection pieces is provided on the link mechanism operation side, and the detection device is provided on the support side that supports the link mechanism. The dog and the detection device are arranged such that the detection device detects one of the detection pieces at a position immediately before the highest position of the loading tray and the other device detects the other detection piece at a position before the lowest position of the loading tray. Then, by detecting the detection device, the lifting speed of the loading tray is reduced through the speed reduction means so as to slowly stop the loading tray at the highest position and the lowest position. As a result, the most upstream position and the most downward position can be detected. This simplifies the structure, facilitates mounting work such as alignment of the dog and the detection device, and reduces manufacturing costs. In addition, since the loading platform is gently stopped at the lowest position and the highest position, it is possible to minimize the impact that occurs on the loading platform when stopping at these positions, and secure the load between the ground and the loading platform. Can be unloaded.
[0082]
Further, according to the loading tray elevating device of the present invention, a dog consisting of two detection pieces formed in a forked shape is provided on the loading tray rotating side, and the dog is detected on the link mechanism side supporting the rotation of the loading tray. A device is provided such that the detection device detects one of the dogs and the detection device at a position in front of the loading tray horizontally and the other detection piece at a position before the standing position of the loading tray. It is arranged so that the rotation speed of the loading tray is reduced through the speed reduction means by the detection of the detection device to slowly stop the loading tray in the horizontal state and the upright state, so that the minimum number of dogs and the detection device As a result, the most upstream position and the most downward position can be detected. This simplifies the structure, facilitates mounting work such as alignment of the dog and the detection device, and reduces manufacturing costs. Moreover, since the loading tray is gently stopped in the horizontal state and the standing state, it is possible to minimize the impact generated on the loading tray when stopping at these positions, and to prevent damage to members due to such impact, The durability can be improved.
[Brief description of the drawings]
FIG. 1 is a side view showing a schematic configuration of a loading tray elevating device in which a loading tray is in a down state at a highest position.
FIG. 2 is a side view showing a schematic configuration of a loading tray lifting device in which the loading tray is in a lifting operation at a lowermost position.
FIG. 3 is a side view showing a schematic configuration of a loading tray elevating device in which the loading tray is tilted at a lowermost position.
FIG. 4 is a side view showing a schematic configuration of a loading tray elevating device in which the loading tray is in an upright state at a highest position.
FIG. 5 is a schematic diagram illustrating a positional relationship between a dog and a detection device.
FIG. 6 is a circuit diagram showing a hydraulic system of the loading tray elevating device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Freight vehicle 10 Support member 5 Lift cylinder 6 Loading table 7 Dog 71 One detecting piece 72 The other detecting piece 8 Detecting device 110 Dog 111 One detecting piece 112 The other detecting piece 120 Detecting device G Ground (ground)
X Loading platform lifting device

Claims (6)

In a loading table lifting device in which the loading table is vertically movable via a link mechanism by a telescopic operation of a lift cylinder between the ground and a loading platform located at a predetermined height from the ground,
A dog including two detection pieces formed in a bifurcated shape is provided on the link mechanism operating side, and a detection device is provided on a support side that supports the link mechanism. The detection device detects one of the detection pieces at a position immediately before the highest rise, and the detection device is arranged to detect the other detection piece at a position before the most downward movement of the load receiving table. A loading tray elevating device configured to reduce the lifting speed of the loading tray and slowly stop the loading tray at the highest position and the lowest position. The lifting device according to claim 1, wherein the speed reduction means includes an electromagnetic proportional valve interposed in a pressure oil supply path to a lift cylinder. The lifting device according to claim 1, wherein the speed reduction unit is configured to reduce a supply amount of pressure oil from a pressure oil supply source. A loading platform is provided between the ground and a loading platform located at a predetermined height from the ground so as to be able to move up and down via a link mechanism by extension and retraction of a lift cylinder, and the loading platform moves up and down by extension and retraction of a tilt cylinder. In a load receiving platform elevating device configured to be rotatable between a horizontal state to be performed and an upright state standing along the rear surface of the loading platform,
A dog consisting of two detection pieces formed in a forked shape is provided on the loading table rotation side, and a detection device is provided on the link mechanism side that supports the rotation of the loading table. Is arranged so that the detection device detects the one detection piece at a position immediately before the loading tray and the detection device detects the other detection piece at a position before the standing position of the loading tray. A loading cradle lifting / lowering device characterized in that the rotation speed of the loading cradle is reduced through a speed reduction means to slowly stop the loading cradle in a horizontal state and an upright state. The lifting device according to claim 4, wherein the speed reduction means includes an electromagnetic proportional valve interposed in a pressure oil supply path to a lift cylinder. 5. The lifting device according to claim 4, wherein the deceleration means is configured to reduce the amount of pressurized oil supplied from a pressurized oil supply source.

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