JP2004243986A - Cargo carrying vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo carrying vehicle capable of eliminating level difference between a bridge platform to transfer cargoes by preventing inclination of a main platform even when the cargoes are transferred in an eccentric condition with respect to the main platform. <P>SOLUTION: A cargo carrying vehicle has detection switches PSW.L and PSW.R on right and left side parts of a bridge platform 52, and lift cylinders 59L and 59R to lift and support a main platform 53 in an elevating/lowering manner. Solenoid control valves 15L and 15R for opening/closing control are provided in pressurized oil branch passages 66L and 66R to each lift cylinder. If any one of the right and left detection switches detects any right or left side part of the main platform, the solenoid control valve for opening/closing control on one side is set at the closed position, and the solenoid valve on the other side is maintained at the unchanged position. If the other side part is detected, the solenoid control valve for opening/closing control on the other side is switched to the closed position. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention mainly relates to an improvement in a freight carrier (high-lift loader) used for carrying cargo into an aircraft at an airport or carrying cargo out of an aircraft.
[0002]
[Prior art]
Conventionally, as shown in schematic diagrams of FIGS. 3A to 3D, when a container 61 which is air cargo is carried into or out of the aircraft 62, the freight carrier 50 is A dolly (coupled bogie) 51 is pulled to the rear.
[0003]
The freight carrier 50 is provided with a bridge platform 52 and a main platform 53 separated from each other in the front and rear. The bridge platform 52 has a scissor link 55 between the front body 54 and lift cylinders (hydraulic cylinders) 56L and 56R on the left and right sides. And the height of the upper surface 52a of the bridge platform 52 at the time of ascending is supported so as to be able to move up and down in the vertical direction so as to form the same horizontal plane as the floor surface 62a of the cargo compartment of the aircraft 62. (A pair of left and right members are denoted by L for a left member, and a right member is denoted by an R).
On the other hand, the main platform 53 is also provided with scissor links 58 and lift cylinders (hydraulic cylinders) 59L and 59R on the left and right sides respectively between the rear platform 57 and the height of the upper surface 53a of the main platform 53 when rising. , Are supported vertically up and down so as to form the same horizontal plane as the upper surface 52a of the bridge platform.
[0004]
The lift cylinders 59L and 59R that support the left and right sides of the main platform 53 so as to be able to move up and down are connected to a common hydraulic source (hydraulic pump) 64 by a main pressure oil circuit 65 and a branch circuit 66. The circuit 65 is provided with an electromagnetic switching valve 67 for raising / lowering control of the lift cylinders 59L, 59R, a flow control valve 68a for raising, a flow control valve 68b for lowering, and the like. A pressure oil return circuit 70 is provided between the up / down control electromagnetic switching valve 67 and the oil tank 69.
[0005]
On the left and right sides of the back surface 52b of the bridge platform 52, detection switches 71L and 71R for detecting the front surface 53b of the main platform 53 are provided. (See Fig. 3 (d))
The dolly 51 includes a fixed platform 60 that does not move up and down.
[0006]
When the cargo carrier 50 having such a configuration loads a container 61, which is air cargo, into the cargo compartment of the aircraft 62, first, the upper surface 52a of the bridge platform 52 is moved in the P direction by an ascending and descending operating device (not shown). The aircraft 62 is raised to the same height as the cargo floor 62a (see FIG. 3A).
[0007]
Next, the container 61 transported by the trailer (container truck) 63 from the container yard to the vicinity of the dolly 51 is transshipped to the platform 60 of the dolly 51 and transferred to the main platform 53 at the lowest position. 3 (a) and 3 (b), a dashed line of the container 61 indicates a transfer state in the arrow Q direction.
[0008]
Subsequently, by operating the ascent / descent control electromagnetic switching valve 67 to the ascending position, the pressure oil is supplied to the left and right lift cylinders 59L and 59R, and the main platform 53 is raised in the R direction. When the left and right side portions of the front 53b of the main platform are detected by the left and right detection switches 71L and 71R, the ascending and descending control electromagnetic switching valve 67 is switched and the pressure oil to the lift cylinders 59L and 59R is switched. The supply is cut off, and the lift cylinders 59L and 59R stop rising. As a result, the lifting of the main platform 53 stops, and the upper surface 53a of the main platform 53 becomes the same horizontal plane as the upper surface 52a of the bridge platform 52 (see FIG. 3B).
[0009]
Subsequently, the container 61 is transported on the upper surface 52a of the bridge platform 52 and is carried into the floor 62a of the cargo compartment of the aircraft. In addition, when carrying out, it is performed by the procedure reverse to the carrying-in method.
[0010]
Such a freight carrier is known (for example, refer to Patent Document 1).
[0011]
[Patent Document 1]
JP-A-6-247205 (FIGS. 1, 2, and 5)
[0012]
[Problems to be solved by the invention]
However, when the container 61 is transshipped from the trailer 63 to the dolly 51 or transferred from the dolly 51 to the main platform 53, the fixed platform 60 or the left and right (left and right toward the traveling direction) of the main platform 53 In some cases.
[0013]
When the main platform 53 is raised in a state where the cargo 61 is biased, that is, in a state where the load due to the container 61 is eccentric, there is a difference between the speeds at which the left and right lift cylinders 59L and 59R extend. As a result, the pressurized oil is always communicated to the left and right lift cylinders 59L and 59R by the branch circuit 66. Therefore, if the load is biased to one of the lift cylinders, the lift cylinder is pushed, and the pressurized oil is applied to the other lift cylinder. The main platform 53 moves and expands, and the height of the left and right lift cylinders 59L and 59R is displaced, and the main platform 53 stops in a state where the main platform 53 is inclined to the eccentric side.
[0014]
Therefore, since a step is formed between the upper surface 53a of the main platform and the upper surface 52a of the bridge platform, the container 61 cannot be transferred to the upper surface 52a of the bridge platform and cannot be carried into the cargo compartment of the aircraft 62.
[0015]
For this reason, the upper surface 53a of the temporarily inclined main platform is flush with the upper surface 52a of the bridge platform by the flow control valves 68a, 68b so that the pressure oil is supplied to the left and right lift cylinders 59L, 59R. The flow must be regulated evenly.
[0016]
Although it is conceivable to provide each lift cylinder independently so that the left and right lift cylinders do not communicate even when the load is eccentric, the number of hydraulic circuits and hydraulic equipment increases, and the manufacturing cost increases.
[0017]
In view of the above-mentioned conventional problems, the present invention can prevent the inclination of the main platform even when the cargo is transferred eccentrically with respect to the main platform, and eliminate the step with the bridge platform to transfer the cargo. It is an object of the present invention to provide a freight carrier that can be used.
[0018]
[Means for Solving the Problems]
The invention according to claim 1 is provided with a bridge platform and a main platform which are supported so as to be able to move up and down, respectively, and separates the bridge platform and the main platform from each other to convey cargo. The left and right lift cylinders are supplied with pressure oil from a common hydraulic source through left and right pressure oil supply branches branched from the main pressure oil supply path, and are disposed on the left and right sides of the bridge platform. The right and left sides of the main platform are detected by the detection switch, and the lift of the main platform is stopped, and the left and right pressure oil supply branches have an open position and a closed position. And a solenoid valve for opening and closing control on the right side, respectively, and the left detection switch is provided on the main platform. When the left side of the system is detected, the left side opening / closing control electromagnetic switching valve is switched from the open position to the closed position, the right side opening / closing control electromagnetic switching valve maintains the position, and the right side detection switch is When the right side of the platform is detected, the right side opening / closing control electromagnetic switching valve is switched from the open position to the closed position. On the other hand, when the right side detection switch detects the right side of the main platform, the right side opening / closing control electromagnetic switching is performed. When the valve is switched from the open position to the closed position, the left open / close control electromagnetic switching valve maintains its position, and when the left detection switch detects the left side of the main platform, the left open / close control electromagnetic switch is used. Switching the valve from the open position to the closed position.
[0019]
With this configuration, when the main platform is raised by the left and right lift cylinders and the left detection switch on the left side of the bridge platform detects the left side of the main platform, the left open / close control electromagnetic switching valve is moved from the open position to the closed position. The supply of the pressurized oil to the left lift cylinder is interrupted, the lift of the left lift cylinder stops, and the lift of the left side of the main platform also stops. The right side detection switch on the opposite side has not yet detected the right side of the main platform, so the open / close control solenoid switching valve on the right side maintains the open position, continues to supply pressure oil to the right side lift cylinder, and the right side lift cylinder. The cylinder keeps rising.
[0020]
However, if the right detection switch detects the right side of the main platform, the open / close control electromagnetic switching valve on the right switches from the open position to the closed position, the supply of pressure oil to the right lift cylinder is cut off, and the right As the lifting of the lift cylinder stops, the right side of the main platform also stops rising.
[0021]
Therefore, the left and right lift cylinders stop at the same amount of extension (stroke), and the left and right ascent of the main platform also stops at the same height.
[0022]
On the other hand, when the right side of the main platform is detected by the detection switch on the right side of the bridge platform, the electromagnetic switching valve for open / close control on the right side is switched from the open position to the closed position, and the supply of pressure oil to the right lift cylinder is shut off. Then, the lift of the right lift cylinder stops, and the lift of the right side of the main platform also stops. Since the left detection switch on the opposite side has not yet detected the left side of the main platform, the left open / close control solenoid directional control valve maintains the open position, continues to supply hydraulic oil to the left lift cylinder, and the left lift The cylinder keeps rising.
[0023]
However, if the left detection switch detects the left side of the main platform, the left open / close control electromagnetic switching valve switches from the open position to the closed position, the supply of pressure oil to the left lift cylinder is cut off, and the left As the lifting of the lift cylinder stops, the lifting of the left side of the main platform also stops.
[0024]
Therefore, the left and right lift cylinders stop at the same amount of extension (stroke), and the left and right ascent of the main platform also stops at the same height.
[0025]
Thus, regardless of which of the left and right sides of the main platform is detected first, the main platform can keep the same surface as the bridge platform, and the step is eliminated.
[0026]
Therefore, the cargo can be transferred from the main platform to the bridge platform without adjusting the flow control valve as in the related art.
[0027]
As described in claim 2, the main pressure oil supply path is provided with an up / down control switching valve having an up position and a down position of the main platform, and the up / down control switching valve is switched. In this case, it is desirable that the left and right opening / closing control electromagnetic switching valves be simultaneously or individually switched from a closed position to an open position.
[0028]
With this configuration, the electromagnetic relay is operated by the ascending lever switch, the ascending / descending control switching valve is switched to the ascending open position, and the energizing control of the left and right opening / closing control electromagnetic switching valves is performed. The electromagnetic relays simultaneously switch the left and right open / close control electromagnetic switching valves from the closed position to the open position. Therefore, the pressure oil from the main pressure oil supply passage can flow to the left and right lift cylinders.
[0029]
Further, even if the opening / closing control electromagnetic switching valve on either one of the left side and the right side is in the closed position, the opening / closing control electromagnetic switching valve on the other side keeps the open position, and the hydraulic oil from the main pressure oil supply passage is released. It can flow to the lift cylinder on the other side.
[0030]
The cargo may be air cargo, and the upper surface of the bridge platform may be held flush with a cargo compartment floor of an aircraft carrying the air cargo, and the cargo may be removed from the main platform. Preferably, the bridge platform is transported and carried into the cargo compartment floor.
[0031]
In this way, when the air cargo is transported eccentrically to the left or right with respect to the main platform, the main platform rises with the eccentric side inclined.
[0032]
However, when the left side of the main platform is detected by the detection switch on the left side of the bridge platform, the solenoid valve for open / close control on the left side is switched from the open position to the closed position, and the supply of pressure oil to the left lift cylinder is shut off. Then, the lift of the left lift cylinder stops, and the lift of the left side of the main platform also stops. The right side detection switch on the opposite side has not yet detected the right side of the main platform, so the open / close control solenoid switching valve on the right side maintains the open position, continues to supply pressure oil to the right side lift cylinder, and the right side lift cylinder. The cylinder keeps rising.
[0033]
However, if the right detection switch detects the right side of the main platform, the open / close control electromagnetic switching valve on the right switches from the open position to the closed position, the supply of pressure oil to the right lift cylinder is cut off, and the right As the lifting of the lift cylinder stops, the right side of the main platform also stops rising.
[0034]
Therefore, the left and right lift cylinders stop at the same amount of extension (stroke), and the left and right ascent of the main platform also stops at the same height.
[0035]
On the other hand, when the right side of the main platform is detected by the detection switch on the right side of the bridge platform, the electromagnetic switching valve for open / close control on the right side is switched from the open position to the closed position, and the supply of pressure oil to the right lift cylinder is shut off. Then, the lift of the right lift cylinder stops, and the lift of the right side of the main platform also stops. Since the left detection switch on the opposite side has not yet detected the left side of the main platform, the left open / close control solenoid directional control valve maintains the open position, continues to supply hydraulic oil to the left lift cylinder, and the left lift The cylinder keeps rising.
[0036]
However, if the left detection switch detects the left side of the main platform, the left open / close control electromagnetic switching valve switches from the open position to the closed position, the supply of pressure oil to the left lift cylinder is cut off, and the left As the lifting of the lift cylinder stops, the lifting of the left side of the main platform also stops.
[0037]
Therefore, the left and right lift cylinders stop at the same amount of extension (stroke), and the left and right ascent of the main platform also stops at the same height.
[0038]
Thus, regardless of which of the left and right sides of the main platform is detected first, the main platform can keep the same surface as the bridge platform, and the step is eliminated.
[0039]
Therefore, the air cargo can be transferred from the main platform to the bridge platform and carried into the cargo compartment of the aircraft without adjusting the flow control valve as in the related art, and the efficiency of the cargo handling operation can be improved.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0041]
1A is a schematic right side view of a freight carrier according to an embodiment of the present invention, FIG. 1B is a plan view of FIG. 1A, and FIG. 2A controls the operation of a lift cylinder. FIG. 2 (b) is an electric control circuit diagram, and FIG. 2 (c) is an explanatory diagram showing a rising process of the main platform in an inclined state.
[0042]
Here, the basic constituent members of the freight carrier 1 shown in FIG. 1 are common to those of FIG. 3 described in the related art, and the same reference numerals are given to these common members, and redundant description will be avoided.
[0043]
As shown in FIGS. 1 (a) and 1 (b), the freight carrier 1 is provided with a bridge platform 52 and a main platform 53 separated from each other at the front and rear. Each can be individually lifted and lowered by the same support method.
[0044]
The driver's seat 2 for performing these lifting and lowering operations is provided above the front vehicle body 54 so that the driver's seat 2 can be shifted to the outside of the bridge platform 52.
[0045]
A first ladder 3 for raising and lowering the driver is provided on the front vehicle body 54, and a second ladder 4 is suspended from the bridge platform 52.
[0046]
Edge members 5 and 6 for preventing the container 61 from dropping in the left-right direction are provided on the left and right sides of the upper surface of the bridge platform 52 and the main platform 53, respectively. Is provided with a handrail 7.
[0047]
Further, on the bridge platform 52, the main platform 53, and the platform 60 of the dolly 51, transport tires 8 and rollers 9 for transporting the container 61 in the front-rear direction are disposed in the front-rear direction.
[0048]
Pulleys 11L and 11R are rotatably attached to the distal ends of piston rods 10L and 10R for the lift cylinders on left and right lift cylinders 59L and 59R which support the left and right sides of the main platform 53 so as to be able to move up and down. Chains 12L and 12R are wound around and covers 13L and 13 for protecting them are provided.
[0049]
One end of each chain is attached to the left and right ends of the main platform 53, and the other end is attached to the left and right ends of the rear carrier 57, respectively.
[0050]
The lifting and lowering and stopping of the left and right lift cylinders 59L and 59R refer to the raising and lowering and stopping of the piston rods 10L and 10R. The extension of the left and right lift cylinders 59L, 59R also refers to the extension (stroke) of the piston rods 10L, 10R.
[0051]
Next, a hydraulic circuit for controlling supply and cutoff of pressure oil to the left and right lift cylinders 59L and 59R and an electric control (sequence control) circuit will be described.
[0052]
As shown in FIGS. 2A to 2C, the lift cylinders 59L and 59R are connected to a common hydraulic pressure source (hydraulic pump) 64 by a main pressure oil circuit 65 and a branch circuit 66. An oil circuit 65 includes a solenoid SOL. For controlling the raising and lowering of the left and right lift cylinders 59L and 59R. An electromagnetic switching valve 14 for raising and lowering control having A, a flow control valve 68a for raising, a flow control valve 68b for lowering, and the like are provided.
[0053]
The branch circuit 66 has an open position and a closed position in the left pressure oil branch passage 66L, and the solenoid SOL. L, an open / close control electromagnetic switching valve 15L having a solenoid valve SOL. An opening / closing control electromagnetic switching valve 15R provided with R is provided. Note that a pressure oil return circuit 70 is provided between the up / down control electromagnetic switching valve 14 and the oil tank 69.
[0054]
These hydraulic control devices are provided at appropriate positions around the driver's seat 2.
[0055]
A left detection switch PSW. Provided on the left and right sides of the back surface 52 (b) of the bridge platform. L and the right side detection switch PSW. R is a normally closed contact type switch that keeps the same height on the left and right (the same height on the ground), and the detection switch circuit is always closed. It turns off.
[0056]
This detection switch is common to the conventional 71L and 71R described with reference to FIG.
[0057]
Subsequently, the lifting operation of the lift cylinders 59L and 59R will be described with reference to FIGS.
(1) When ascending
(1) Lift lever switch SW. A is turned on, so that the electromagnetic relay RELY. A operates (energizes the coil) and the contact is closed to send an ON signal, and the solenoid SOL. The position is switched to the open position by A, and the pressure oil from the hydraulic pressure source 64 flows to the main circuit 65 and the branch circuit 66.
[0058]
Further, the left detection switch PSW. L and the right side detection switch PSW. R is controlled by a signal from the left electromagnetic relay RELY. L and the right electromagnetic relay RELY. R indicates that the coil is energized, the contact is closed, and a signal of ON is transmitted, and the electromagnetic switching valve SOL. L and the solenoid-operated switching valve SOL. R is switched to the open position, pressure oil is supplied to the left and right lift cylinders 59L, 59R, and the lift cylinders rise in synchronization.
{Circle around (2)} The main platform 53 rises with the rise of each lift cylinder, and the left detection switch PSW. L and the right side detection switch PSW. R simultaneously detects the left and right sides of the main platform 53, the signals of the respective detection switches are turned off, and the left electromagnetic relay RELY. L and the right electromagnetic relay RELY. R, the contact is opened, the signal is turned off, and the electromagnetic switching valve SOL. L and the solenoid-operated switching valve SOL. R switches to the closed position and shuts off the supply of pressure oil to the left and right lift cylinders 59L and 59R.
[0059]
As a result, each lift cylinder stops rising with the same amount of elongation (stroke), and stops lifting the main platform together with the stop of each lift cylinder. The upper surface 53a of the main platform 53 becomes the upper surface 52a of the bridge platform 52. And keep the same horizontal plane.
(3) However, when the left and right detection switches individually detect the left and right sides of the main platform 53,
For example, when the load (air cargo container 61) is eccentric on the right side of the main platform 53 and the upper surface 53a of the main platform 53 rises with the right side inclined downward, the detection switch PSW. L detects the left side of the main platform 53 first, so that the left electromagnetic relay RELY. L is turned off, and the electromagnetic switching valve SOL. L switches to the closed position, and shuts off the supply of pressure oil to the left lift cylinder 59L. As a result, the lifting of the left lift cylinder 59L stops (the state of (Y) in FIG. 2C).
[0060]
However, the right detection switch PSW. L does not detect the right side of the main platform. R maintains the open position, and the right lift cylinder 59R rises. Thereafter, the right detection switch PSW. R detects the right side of the main platform 53, the signal is turned off, and the electromagnetic relay RELY. R is also OFF, and the electromagnetic switching valve SOL. R switches to the closed position and shuts off the supply of pressure oil to the right lift cylinder 59R. As a result, the lift of the right lift cylinder 59R stops (the state changes from (Y) in FIG. 2C to (Z) in the direction of arrow S in FIG. 2C).
[0061]
Therefore, the left and right lift cylinders 59L and 59R stop rising at the same amount of extension (stroke), and the left and right lifts of the main platform 53 stop at the same height as the left and right lift cylinders 59L and 59R stop.
{Circle around (4)} On the other hand, when the load (air cargo container 61) is eccentric on the left side of the main platform 53 and the upper surface 53a of the main platform 53 rises with the left side inclined downward, the detection switch PSW. R detects the right side of the main platform 53 first, so that the right side electromagnetic relay RELY. R signal is turned off, and the electromagnetic switching valve SOL. R switches to the closed position and shuts off the supply of pressure oil to the right lift cylinder 59R. As a result, the lift of the right lift cylinder 59R stops.
[0062]
However, the left detection switch PSW. L does not detect the left side of the main platform. L maintains the open position, and the left lift cylinder 59L rises. Thereafter, the left detection switch PSW. L detects the left side of the main platform 53, the signal is turned off, and the left electromagnetic relay RELY. L is also OFF, and the electromagnetic switching valve SOL. L switches to the closed position, and shuts off the supply of pressure oil to the left lift cylinder 59L. As a result, the lift of the left lift cylinder 59L stops.
[0063]
Therefore, the left and right lift cylinders 59L and 59R stop rising at the same amount of extension (stroke), and the left and right lifts of the main platform 53 stop at the same height as the left and right lift cylinders 59L and 59R stop.
[0064]
Since the hydraulic and electric control circuits are configured as described above, even if the load rises eccentrically to the left or right of the main platform 53, the left and right detection switches PSW. L and PSW. R can be individually detected, and the upper surface 53a of the main platform 53 can be held on the same horizontal plane as the upper surface 52a of the bridge platform 52, thereby eliminating the step.
[0065]
Therefore, the container 61, which is air cargo, can be transferred from the main platform 53 to the bridge platform 52 and carried into the cargo compartment of the aircraft 62 without adjusting the flow regulating valve as in the related art. Efficiency can be increased.
(2) When descending
The lowering lever switch SW. B is turned on, so that the electromagnetic relay RELY. B operates (energizes the coil), the contact is closed and a signal of ON is transmitted, and the solenoid SOL. L and the solenoid SOL. With R, the pressure is switched to the open position, and the pressure oil of the left and right lift cylinders 59L, 59R is returned via the left and right open / close control electromagnetic switching valves 15L, 15R, and the branch circuit 66, the main circuit 65, and the rising The return circuit 70 returns to the oil tank 69 via the lowering control electromagnetic switching valve 14 and the like.
[0066]
As a result, the left and right lift cylinders 59L and 59R descend, and the main platform 53 returns to the lowest position.
[0067]
In this embodiment, since the left and right lift cylinders 59L and 59R are single-acting, the lowering of the ascending / descending control electromagnetic switching valve 14 is manually switched, and the descending solenoid is not required.
[0068]
Further, the electromagnetic switching valve 14 for ascending / descending control may be a manual switching valve.
[0069]
Next, as another embodiment, an up / down control switching valve 14 having an up position and a down position of the main platform 53 is provided in the main pressure oil supply path 65, and the up / down control switching valve 14 is provided. Is switched, it is desirable that the left and right open / close control electromagnetic switching valves 15L, 15R be simultaneously or individually switched from the closed position to the open position.
[0070]
By doing so, the lifting lever switch SW. A for the electromagnetic relay RELY. A operates (energizes the coil), the contact is closed, and an ON signal is transmitted to switch the ascending / descending control switching valve 14 to the ascending open position, and the left and right opening / closing control electromagnetic switching valves 15L, 15R that transmits an ON signal for controlling the electromagnetic relay RELY. L and RELY. By R, the left and right open / close control electromagnetic switching valves 15L and 15R are simultaneously switched from the closed position to the open position. Therefore, the pressure oil from the main pressure oil supply passage can flow simultaneously to the left and right lift cylinders 59L and 59R.
[0071]
In addition, the contact point of the electromagnetic relay (RELY.L or RELY.R) on one of the left side and the right side is opened and the signal is turned off, and the electromagnetic switching valve (15L or 15R) for open / close control on one side is set to the closed position. Switch.
[0072]
That is, even if the one-way opening / closing control electromagnetic switching valve is in the closed position, the other-side opening / closing control electromagnetic switching valve keeps the open position, and the pressure oil from the main pressure oil supply passage 65 is supplied to the other side lift cylinder. Can be flushed.
[0073]
【The invention's effect】
The present invention is implemented as described above, and has the following effects.
[0074]
According to the present invention, when the load due to the cargo is eccentric to one of the left and right sides of the main platform and rises from the lowest position, one of the left and right detection switches individually detects the load. Can be held on the same horizontal plane as the upper surface.
[0075]
Therefore, by eliminating the step, the cargo can be efficiently transferred from the main platform to the bridge platform without adjusting the flow control valve as in the related art.
[Brief description of the drawings]
FIG. 1 (a) is a schematic right side view of a freight carrier according to an embodiment of the present invention, and FIG. 1 (b) is a plan view of FIG. 1 (a).
2 (a) is a hydraulic circuit diagram for controlling the operation of a lift cylinder, FIG. 2 (b) is an electric control circuit diagram, and FIG. 2 (c) is an explanatory diagram showing a rising process of a main platform in an inclined state. It is.
FIG. 3 (a) is a schematic right side view of a conventional freight carrier when the bridge platform is raised, and FIG. 3 (b) is a right side when the bridge platform and the main platform of the conventional freight carrier are raised. FIG. 3 (c) is a hydraulic circuit diagram for controlling the operation of a lift cylinder in a conventional freight carrier, and FIG. 3 (d) is a conventional freight carrier taken along the line AA in FIG. 3 (a). It is explanatory drawing which shows the arrangement | positioning of the detection switch of the bridge platform right and left side part in a vehicle.
[Explanation of symbols]
1 freight carrier
14 Electromagnetic switching valve for up / down control
15L electromagnetic switching valve for left side opening / closing control
15R Solenoid switching valve for right side opening / closing control
52 Bridge Platform
52a Top of bridge platform
53 Main Platform
59L left lift cylinder
59R Right lift cylinder
61 Container (air cargo)
62 aircraft
62a Cargo compartment floor
64 hydraulic power source
65 Main pressure oil supply path
66L left pressure oil supply branch
66R Right pressure oil supply branch
PSW. L Left detection switch
PSW. R Right detection switch

Claims (3)

A bridge platform and a main platform, which are supported to be able to move up and down, are provided separately in front and rear, respectively, to convey cargo, and left and right lift cylinders which support the left and right sides of the main platform so as to be able to move up and down. Is supplied with pressure oil from a common hydraulic source through left and right pressure oil supply branch paths branched from the main pressure oil supply path, and the main platform is detected by detection switches disposed on the left and right sides of the bridge platform. In the freight carrier that detects the left and right sides of the main platform and stops lifting the main platform,
The left and right pressure oil supply branch passages are provided with left and right open / close control electromagnetic switching valves having an open position and a closed position, respectively.
When the left-side detection switch detects the left side of the main platform, the left-side open / close control electromagnetic switching valve switches from the open position to the closed position, and the right-side open / close control electromagnetic switching valve maintains the position, When the right detection switch detects the right side of the main platform, the right open / close control electromagnetic switching valve is switched from the open position to the closed position,
When the right detection switch detects the right portion of the main platform, the right open / close control electromagnetic switching valve is switched from the open position to the closed position, and the left open / close control electromagnetic switching valve is maintained at the position. A freight carrier, wherein when the left detection switch detects a left portion of the main platform, the left open / close control electromagnetic switching valve is switched from an open position to a closed position. The main pressure oil supply path is provided with an up / down control switching valve having an up position and a down position of the main platform, and when the up / down control switching valve is switched, the left and right opening and closing are performed. 2. The freight carrier according to claim 1, wherein the control electromagnetic switching valve is simultaneously or individually switched from a closed position to an open position. The cargo is air cargo, and an upper surface of the bridge platform is held at the same level as a cargo compartment floor of an aircraft carrying the air cargo, and the cargo is transferred from the main platform to the cargo platform by transferring the cargo platform from the main platform. The freight carrier according to claim 1, wherein the freight carrier is configured to be carried into a room floor.

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