JPH0351222Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention has a so-called dump function that is configured so that the loading platform can be tilted in the longitudinal direction with respect to the main frame equipped with traveling devices such as crawlers and wheels. The present invention relates to a loading platform posture control device for a transport vehicle.

[Prior art]

Transport vehicles equipped with platforms for transporting various heavy objects, such as agricultural and forestry transport vehicles used for transporting seedlings, fertilizers, harvested products, and shiitake mushrooms, are equipped with crawlers, wheels, etc. The so-called dump function allows the cargo loaded on the platform to fall from the rear of the platform by tilting the entire platform by lifting and rotating the front part of the platform relative to the main frame equipped with the traveling device. generally have.

[Problem that the invention attempts to solve]

Incidentally, in recent years, a cargo platform attitude control device has been developed that is configured to maintain the cargo platform at a constant inclination or horizontally with respect to a horizontal surface in order to avoid overturning, cargo collapse, etc. when a transport vehicle travels on a slope. , and its practical application is progressing.

However, there are problems, such as the following, when applying such a loading platform attitude control device to a conventional transport vehicle.

With a conventional transport vehicle, for example, when going down a mountain road, it is in forward motion, and when climbing a hill, it is in backward motion, that is, in both cases, the transport vehicle is tilted forward onto the mountain road, and the front part of the loading platform is moved forward. After the robot was raised and rotated until it was tilted to an almost horizontal position, it was automatically controlled. For this reason, if the slope changes from downhill to uphill, or vice versa, while driving on a mountain road, the direction of travel of the transport vehicle should be reversed each time, or the loading platform should be moved parallel to the main body of the transport vehicle. I had to take steps to do so. Of course, in the above case, if the loading platform is made parallel to the carrier body, the loading platform will not be horizontal, and therefore it is impossible to maintain and control the loading platform horizontally.

Therefore, a sub-frame is provided between the main frame on the main body side of the transport vehicle and the loading platform. The rear part of the loading platform is pivoted to the rear end of this sub-frame, and the front part thereof is movable up and down with respect to the sub-frame, in other words, with respect to the main frame. It is conceivable that the loading platform can be maintained horizontally regardless of the tilted state of the vehicle body.

However, when adopting the above-mentioned configuration, by appropriately controlling both the rotation of the upper frame relative to the sub-frame and the rotation of the sub-frame relative to the main frame, the upper frame to which the loading platform is attached can be moved. Control is performed so that the level is maintained at all times, but unless one of these is used as a reference for control, the control becomes complicated and may cause malfunctions or accidents.

[Means for solving problems]

The present invention was developed in view of the above-mentioned circumstances, and includes a sub-frame between the main frame on the main body side and the loading platform, and for example, the sub-frame is pivoted at its front end closer to the front end of the main frame. The rear part of the loading platform can be moved up and down relative to the main frame, and the rear part of the loading platform is pivoted to the rear end of this sub-frame, and the front part is moved relative to the sub-frame, in other words, relative to the main frame. By being configured to be movable up and down, the loading platform can be controlled horizontally regardless of the tilted state of the carrier vehicle body. Further, the control for maintaining the loading platform in a horizontal state is started only when the upper frame is parallel to the sub-frame, or when the sub-frame is parallel to the main frame, It is an object of the present invention to provide a loading platform posture control device for a transport vehicle that can solve the above-mentioned problems by setting standards for control by a control device.

The loading platform posture control device for a transport vehicle according to the present invention has one end in the front and back direction pivoted to one end in the front and back direction of a main frame equipped with a traveling device, and the other end in the front and back direction is pivoted up and down. a first sensor for detecting a rotation angle of a movably configured sub-frame with respect to the main frame; a second sensor for detecting the rotation angle of the upper frame, which is configured to be movable up and down on the other side end in the front-rear direction, with respect to the sub-frame; and an absolute angle with respect to the horizontal plane of the loading platform attached to the upper frame. and a third sensor for detecting the upper The control is performed only when it is detected that the frame and the sub-frame are parallel, or when the first sensor detects that the sub-frame and the main frame are parallel. Features what we did to get started.

〔Example〕

Hereinafter, the present invention will be described in detail based on drawings showing embodiments thereof.

Fig. 1 is a schematic perspective view of a transport vehicle equipped with a loading platform posture control device according to the present invention (hereinafter referred to as the proposed device) as seen from the rear right side, and Fig. 2 is a plan view showing the structure of the frame of the loading platform portion. , FIG. 3 is a side sectional view taken in the direction of the - line arrow in FIG. 2.

In the figure, 10 is the main frame of the transport vehicle, and the chassis 12 has left and right traveling crawlers 11, 11 attached.
mounted on top. The front side of the main frame 10 extends further forward than the front end of the traveling crawler 11, and the driver's seat 1 and the power section 14 are mounted above this extended portion.

A loading platform 20 is provided above the rear of the main frame 10 so that it can be tilted (dumped) and raised and lowered in the front-rear direction. The sub-frame 30 is attached to a portion close to the main frame 10 so as to be rotatable vertically relative to the sub-frame 30, and the sub-frame 30 is attached to a portion near the front end of the sub-frame 30 such that the sub-frame 30 is rotatable vertically relative to the main frame 10. . By adopting such a configuration, the sub frame 30 rotates in the vertical direction with respect to the main frame 10 around its front part, and the upper frame 40 rotates its rear part with respect to the sub frame 30. By rotating in the vertical direction about the center, the loading platform 20 is configured to be able to tilt and move up and down both forward and backward relative to the main frame 10.

Note that the tilting of the loading platform 20 in the front-rear direction refers to a rotational movement of the loading platform 20 with respect to the carrier body with one of its front and rear ends as the center of rotation,
Lifting means that the loading platform 20 moves up and down with respect to the carrier vehicle body while maintaining the parallel state between the carrier vehicle body and the loading platform 20. Moreover, the slope of the loading platform 20 is
There are two methods: forward raising, in which the front end of the loading platform 20 is rotated in an upward direction relative to the carrier body, with the rear end of the loading platform 20 as the rotation center; There is a front lowering that rotates upwards.

First, the main frame 10 includes left and right traveling crawlers 1.
The left and right chassis members 12l of the chassis 12 support the rotating shafts of drive wheels, guide wheels, etc. 1 and 11,
Left and right main frame members 10l and 10r are attached to the upper side of each frame member 12r. These left and right main frame members 10l, 10
On both sides of the slightly rearward side of the driver's seat 1 of the r, there are left and right brackets 16 with their upper parts protruding upwards from the left and right main frame members 10l and 10r, respectively.
l, 16r are attached. A rotation shaft 17 is located between the left and right brackets 16l and 16r.
is rotatably inserted through the rotating shaft 17, and left and right sub-frame members 30 constituting the sub-frame 30 are inserted between the left and right brackets 16l and 16r of the rotating shaft 17.
Portions near the front ends of 1 and 30r are each fixed.

Also, the left and right brackets 16 of the main frame 10
A square pipe beam 18 is fixed between the left and right main frame members 10l and 10r slightly behind l and 16r, while a square pipe beam 18 is fixed at approximately the middle of the sub-frame 30 and from the fixed position of the beam 18. A square pipe beam 31 is also fixed between the left and right sub-frame members 30l and 30r at the rear position. A hydraulic cylinder 32 is supported by a trunnion at approximately the center of the beam 17 in the left-right direction, and the hydraulic cylinder 32 lowers the loading platform 20 forward by the advancement of the piston rod 32R. It is pivotally supported by a square pipe beam 31 fixed on the side 30. Therefore, by supplying and discharging pressure oil to the hydraulic cylinder 32, the sub frame 30 is rotated with a portion near its front end as a rotation center at a position slightly rearward of the driver's seat 1 of the main frame 10. Note that the rotation angle of the sub frame 30 with respect to the main frame 10 is
The range is from 0° to -15° (when the piston rod 32R advances, the loading platform 20 tilts forward and downward).

The right bracket 16r attached to the right main frame member 10r is equipped with a front position sensor 51 using a potentiometer, and the detected value F0 is determined by the rotation of the rotation shaft 17 with respect to the right bracket 16r. By detecting the movement angle, the rotation angle of the sub frame 30 relative to the main frame 10 is expressed.

At the rear end of the sub-frame 30, left and right brackets 33l and 33r are fixed at the front upper portions of the left and right sub-frame members 30l and 30r, respectively, on the outer sides thereof. These left and right brackets 33l, 33
A rotation shaft 34 is rotatably inserted into the rearwardly protruding portion of each sub-frame 30. On the other hand, left and right brackets 41l and 14r are provided on the outside of the portion near the rear end of each of the left and right upper frame members 40l and 40r constituting the upper frame 40, and are attached so as to protrude downward. Upper frame member 40l, 4
Left and right brackets 41l, 41 fixed at 0r
r is fixed to the rotation shaft 34 mentioned above.

In addition, the left and right brackets 33 of the sub frame 30
A square pipe beam 35 is fixed between the lower front end portions of the upper frames 40 and 33r, and the left and right upper portions are located approximately in the middle of the upper frame 40 and at approximately the same position as the beam 31 is fixed. Frame member 40
A square pipe beam 42 is also fixed between l and 40r. A front-lifting hydraulic cylinder 43 is supported by a trunnion at approximately the center in the left-right direction of the beam 35, and the front-lifting hydraulic cylinder 43 raises the loading platform 20 forward by the advance of its piston rod 43R. The rod end is pivotally supported by a beam member 42 fixed to the upper frame 40 side. Therefore, by supplying and discharging pressure oil to and from the hydraulic cylinder 43, the upper frame 40 is rotated with a portion near the rear end of the sub frame 40 at the position of the rear end of the sub frame 30 as the center of rotation. The rotation angle with respect to the upper frame 30 is in the range of 0° to +60° (the piston rod 43R advances and the loading platform 20 rotates forward and upward).

The right bracket 33l attached to the right sub-frame member 30r is equipped with a rear position sensor 52 using a potentiometer, similar to the front position sensor 51 described above, and its detected value R0 represents the relative rotation angle of the upper frame 40 with respect to the sub-frame 30 by detecting the rotation angle of the rotation shaft 34 with respect to the right bracket 33r.

Further, on the upper frame 40, two frame members 45l, 45r in the front and back direction are provided further outside of the left and right upper frame members 40l, 40r, to which the above-mentioned beam material 42 and left and right brackets 41l, 41r are attached. 46l and 46r, respectively, and these six longitudinal upper frame members 41l, 41r, 45l, 45
r, 46l, and 46r are assembled into a frame shape by beam members 47b and 47f that constitute the front and rear end beam members of the upper frame 40. And this frame-shaped upper frame 4
A loading platform 20 is placed and fixed on the upper surface of the vehicle.

In addition, a suitable member of the upper frame 40 is provided with a loading platform sensor 53 approximately in the center in the front-rear direction for detecting the absolute inclination angle of the upper frame 40, in other words, the loading platform 20, with respect to the horizontal plane. The detected value NO represents the absolute inclination angle of the loading platform 20 with respect to the horizontal plane, regardless of the inclination state of the main frame 10, the expansion/contraction state of the hydraulic cylinders 32, 43, etc.

Therefore, the loading platform 20 is equipped with a hydraulic cylinder 3 for lowering the front.
When the piston rod 32R of No. 2 moves forward, its rear end rotates in the upward direction with its front end as the center of rotation, resulting in a forward downward tilted state, and the piston rod 43R of the hydraulic cylinder 43 for forward raising.
When the front end moves forward, the front end rotates in the upward direction with the rear end as the center of rotation, resulting in a front-up tilted state. Further, from the state where the loading platform 20 is parallel to the carrier body, both piston rods 32R and 43R advance by the same amount (actually, alternately as described later),
Alternatively, when retracting, the loading platform 20 rises or descends while maintaining a state parallel to the carrier body.

FIG. 4 is a schematic diagram showing the postures that the loading platform 20 can take.
FO = 0°), and the sub frame 30 and the upper frame 40 are parallel (rear position sensor 52
The case where the detected value RO = 0°) is shown. FIG. 4b shows the case where the upper frame 40 has rotated to its limit in the direction away from the sub-frame 30 from the state shown in a (RO=+60°, FO=0°).
Figure 4c shows the case where the subframe 30 has further rotated to its limit in the direction away from the main frame 10 from the state shown in b (RO = 60°, FO = -15°). In this case, the angle of the loading platform 20 with respect to the horizontal plane, that is, the detected value NO of the loading platform sensor 53 is +45°. Fig. 4 d shows the upper frame 4 from the state shown in c.
0 is rotated to its limit in the direction approaching the sub-frame 30 to make them parallel (RO=
0°, FO = -15°), and in this case, the angle of the loading platform 20 with respect to the horizontal plane, that is, the loading platform sensor 53
The detected value NO is −15°. Furthermore, this figure 4d
From the state, the sub frame 30 is further changed to the main frame 10.
If it is rotated in the direction approaching , and the two are parallel, it will return to the state shown in a. FIG. 4e shows the upper frame 40 in relation to the sub-frame 30 from the state shown in a.
The upper frame 4 is rotated by alternately rotating the sub frames 30 by approximately equal angles with respect to the main frame 10.
0, that is, the loading platform 20 is raised to its upper limit while maintaining a state parallel to the main frame 10 (RO=15°, FO=−15°).

As shown in FIG. 1, the driver's seat 1 is equipped with a power section 14 equipped with an engine, a transmission, etc. on the left side,
Almost in the center is a control box 2 containing the control circuit of the proposed device (see Figure 7) and a control console in which a travel clutch lever 3 and other elements are arranged in the front-rear direction, and on the right side is a seat 5 for the operator. , control levers 4l, 4r, etc. are provided.
The clutch lever 3 is equipped with a clutch sensor 54 (see FIG. 7) that detects the operation of the clutch lever 3, in other words, the change from a running state to a stopped state, or from a stopped state to a running state. .

By the way, on the surface of the control box 2, there is provided an operation panel 6 of the present device as shown in FIG. A mode switch 61, a loading platform switch 62, a lift switch 6, and a cylinder speed changeover switch 64 are arranged on this operation panel 63.
And the function of the vibration switch 65 will be briefly explained.

First, the mode switch 61 has a three-position selection type, including manual mode, automatic mode, and parallel mode.
Modes are now selectable. When manual mode is selected by this mode switch 61,
An operator can manually control the inclination of the loading platform 20 by operating the loading platform switch 62, and can also vibrate the loading platform 20 by turning on the vibration switch 65. When the automatic mode is selected, automatic control is performed to maintain the loading platform 20 horizontally regardless of the inclination of the carrier body, but priority is given to controlling the inclination of the loading platform 20 by manual operation of the loading platform switch 62. Furthermore, when the tilt control of the loading platform 20 by the loading platform switch 62 is stopped, the automatic mode is immediately returned.
When the parallel mode is selected, the loading platform 20 and the carrier body, specifically, the upper frame 40 and the sub-frame 30 are parallel (detection value RO of the rear position sensor 52 = 0°), and the sub-frame 30 and the sub-frame 30 are parallel. Main frame 1
0 is parallel to the main body of the transport vehicle (detected value FO of the front position sensor 51 = 0°), and the loading platform 20 becomes parallel to the main body of the transport vehicle at the position closest to the main body of the transport vehicle (the fourth
Figure a). In addition, by operating the lift switch 63 in this state, the loading platform 20 can be moved in a state where the parallel relationship between the loading platform 20 and the transport vehicle body is maintained.
It is possible to raise and lower (lift up and lift down).

The loading platform switch 62 is a switch that tilts (dumps) the loading platform 20, and when operated to the "up" position, the loading platform 20 moves forward (from a to b in FIG. 4).
(in the order c), and when it is in the "down" position, the loading platform 20 becomes the forward lowered state (in the order c→d→a in FIG. 4). In addition, when this loading platform switch 62 is operated,
Regardless of the mode selected by the mode switch 61 described above, priority is given to manual control for tilting the loading platform 20 by operating the loading platform switch 62.

The lift switch 63 is a volume type switch, and raises and lowers the loading platform 20 to a height position corresponding to its rotational position while maintaining a parallel relationship with the transport vehicle body (as shown in Fig. 4 a→e). However, when the parallel mode is selected by the mode switch 61 mentioned above and the loading platform 20 is at the lowest position relative to the carrier body (the upper frame 40 is rotated relative to the sub-frame 30 as shown in FIG. The operation is effective only when the rotation angle of the angle and the rotation angle of the sub frame 30 with respect to the main frame 10 are both 0 degrees) and the operation is performed from "low" to "high".

The cylinder speed changeover switch 64 controls the tilting or lifting speed of the loading platform 20 when the automatic mode is selected by the mode switch 61 (specifically, the rod drive speed of the hydraulic cylinders 32 and 43).
``Speed'', in which both piston rods 32R and 43R are driven relatively quickly;
``Slow'' where both piston rods 32R and 43R are driven relatively slowly, and ``Medium'' which is between the two.
The speed of the steps is selectable. As will be described later, the speed is automatically selected as "medium" in the manual mode, "medium" or "slow" in the parallel mode, and "slow" when the loading platform 20 is raised or lowered by the lift switch 63. In addition, sub frame 30
Alternatively, immediately before the rotation of the upper frame 40 is stopped, the cylinder speed is controlled relatively slowly, as will be described later.

The vibration switch 65 causes the loading platform 20 to vibrate, that is, to repeatedly rotate the loading platform 20 several degrees (5 degrees in this embodiment) with the loading platform 20 tilted upward (a state between a and b in FIG. 4). This is a control in which the main body rotates in the vertical direction, and is carried out, for example, when it is necessary to drop earth and sand loaded on the loading platform 20 while the main body is traveling.

FIG. 6 is a hydraulic circuit diagram of the main parts of a transport vehicle equipped with the present device.

In the figure, numerals 32 and 43 are the aforementioned hydraulic cylinders, to which pressure oil is supplied and discharged by four-port, three-position switching type electromagnetic directional control valves V2 and V3. Both electromagnetic directional control valves V2 and V3 each have a solenoid
When Su2 and Su3 are energized, they each move to the switching position u and pressurized oil is supplied to the oil chamber on the advancing side, which causes the piston rods 32R and 43R to advance in the direction in which the sub frame 30 is separated from the main frame 10 (front Detection value FO of position sensor 51
is 0° → 15°, the loading platform 20 is lowered forward), or the direction in which the upper frame 40 is separated from the sub frame 30 (the detection value RO of the rear position sensor 52 is 0°)
→ +60°, the loading platform 20 is raised forward), and the inclination becomes large, and the solenoid
When Sd2 and Sd3 are energized, each moves to the switching position d, and pressurized oil is supplied to the oil chamber on the retraction side, which causes the piston rods 32R and 43R to retract in a direction in which the sub frame 30 approaches the main frame 10. (The detection value FO of the front position sensor 51 is -
15° → 0°, the loading platform 20 is raised forward), or the direction in which the upper frame 40 approaches the sub-frame 30 (the detection value RO of the rear position sensor 52 is +60°)
→0°, the loading platform 20 is lowered forward), and the inclination becomes smaller, and both solenoids Su2 and
If Sd2 or both Su3 and Sd3 are not excited, they are at the neutral position n, and both hydraulic cylinders 32, 43
The pressure oil in the oil chamber is sealed and both piston rods 3
2R and 43R are locked at their current positions.

Further, the two electromagnetic directional control valves V2 and V3 do not directly receive pressure oil supply from the hydraulic pump P, but another electromagnetic directional control valve V1 is interposed between them and the hydraulic pump P. Double solenoid directional control valve V
2. Pressure oil supply to V3 is being switched. The electromagnetic directional control valve V1 for switching is a 4-port 2-position switching type, and when the solenoid S1 is demagnetized, the pressure oil discharged from the hydraulic pump P is connected to the hydraulic cylinder 43 for forward lifting. When the solenoid S1 is energized, the hydraulic pump P
Pressure oil discharged from the front lowering hydraulic cylinder 3
It is supplied to the electromagnetic directional control valve V2 interposed between the

Even though both electromagnetic directional control valves V2 and V3 each have a neutral position n, in this way, the electromagnetic directional control valve V1 is configured to supply pressure oil only to either of the electromagnetic directional control valves V2 and V3. The reason for this is that when the electromagnetic directional control valve V1 is not used, each solenoid Su2,
Four systems of signals are required to control Su3, Sd2, and Sd3. However, when using the configuration shown in Fig. 6, solenoids Su2 and Su3 of both electromagnetic directional control valves V2 and V3 are connected to the same signal Sd.
2 and Sd3 are each controlled by one signal system,
This is because by combining this with the signal that controls the solenoid S1 of the electromagnetic directional control valve V1, it becomes possible to control both hydraulic cylinders 32 and 43 with three systems of signals.

FIG. 7 is a block diagram of the control circuit of the present device.

In the figure, 71 is a control unit using a CPU, ROM, RAM, etc., and includes input ports a ₁ to a ₄ to which analog signals are input, and input ports to which digital signals are input.
Output port where _d1 to _d8 and digital signals are output
b ₁ to b ₃ are provided. Note that a ₀ is a power supply terminal, and a power supply voltage is supplied from a battery 70 via a key switch 75.

The input port _a1 is connected to the front position sensor 51 described above, that is, the main frame 10 of the sub frame 30.
Relative inclination angle to (front lowering angle of loading platform 20)
The output (detection value FO) _of the sensor 51 that detects the
2, that is, the output (detection value RO) of the sensor 52 that detects the relative inclination angle of the upper frame 40 with respect to the sub-frame 30 (the forward raising angle of the loading platform 20) is given, and the above _- mentioned horizontal plane of the loading platform 20 is given to The output (NO) of the loading platform sensor 53 that detects the absolute angle with respect to the horizontal axis is given as an analog electrical signal. To explain the detection range of each of these sensors 51 to 53, all of the sensors cover the loading platform 20.
The detected value when the front is raised is +, and the detected value when the front is lowered is -. Therefore, the detection range of the front position sensor 51 is ±0° to -15°, and the detection range of the rear position sensor 52 is ±0° to +
60°, and the detection range of the loading platform sensor 53 is ±15°.

A clutch sensor 54 is connected to the input port _d1 . This clutch sensor 54 inputs a high-level signal to the input port d ₁ when the clutch lever 3 comes into contact with the clutch lever 3 each time the clutch lever 3 is operated, in other words, each time the transport vehicle starts or stops. It is prohibited to operate the vehicle immediately after starting or stopping the vehicle. Note that the clutch sensor 54 may be an optical sensor such as a photo interrupter.

Two contacts 61M and 61A of the mode switch 61 of the operation panel 6 mentioned above are connected to the input ports d ₂ and d ₃ , respectively. That is, when the manual mode is selected by the mode switch 61, the contact 61M is closed and a high level signal is sent to the input port.
d ₂ and when automatic mode is selected, contact 61A is closed and a high level signal is input to input port d ₃ , and when parallel mode is selected, both contacts 61M and 61A are closed. By closing the circuit and inputting high-level signals to both input ports d ₂ and d ₃ , the control unit 74 recognizes the selected mode.

Two contacts 62u and 62d of the load platform switch 62 of the aforementioned operation panel 6 are connected to the input ports _d4 and _d5 , respectively. That is, the loading platform switch 62
When is operated to the "up" side, the contact 62u is closed and a high level signal is input to the input port _d4 , and when it is operated to the "down" side, the contact 62d is closed and a high level signal is input. When the signal is input to the input port _d5 , the control unit 74 recognizes an instruction to raise or lower the loading platform 20.

An analog voltage signal representing the lift position (elevating height) of the loading platform 20 set by the lift switch 63 of the operation panel 6 is applied to the input port _a4 .

Two contacts 64h of the cylinder speed changeover switch 64 on the operation panel 6 are connected to the input ports _d6 and _d7 .
64l are connected to each other. That is, as described above, when the automatic mode is selected by the mode switch 61, the operating speed of the hydraulic cylinders 43, 32 for forward raising or lowering can be set by the cylinder speed changeover switch 64. As a result, when "speed" is selected, contact 64h is closed and a high level signal is sent to the input port.
When input to _d6 and "slow" is selected, contact 64l is closed and a high level signal is sent to the input port.
When input to d ₇ and "Medium" is selected, both contacts 64h and 64l are closed and a high level signal is input to both input ports d ₆ and d ₇ , thereby indicating selection. The control unit 74 recognizes the cylinder speed.

The vibration switch 65 of the operation panel 6 is connected to the input port d ₈ , and when the vibration switch 65 is turned on, a high-level signal is input to the input port a ₈ to control the vibration of the loading platform 20 . The control unit 74 recognizes the instruction.

On the other hand, a switching transistor 72 in which a solenoid S1 of the electromagnetic directional control valve V1 described above is interposed between the battery 70 and the output port _b1 is connected. Therefore, when a high level signal is output from the output port _b1 , the solenoid S1 is energized, and the pressure oil discharged from the hydraulic pump P is thereby transferred to the electromagnetic directional control valve connected to the forward lowering hydraulic cylinder 32. It is fed to the V2 side. reverse output port
When the signal output from b ₁ is low level, the solenoid S1 is demagnetized, and the pressure oil discharged from the hydraulic pump P is thereby transferred to the electromagnetic directional control valve V3 connected to the forward lifting hydraulic cylinder 43. sent to the side.

Connected to the output port _b2 is a switching transistor 72 in which solenoids Su2 and Su3 for advancing the rods of the electromagnetic directional control valves V2 and V3 are interposed in parallel between the battery 70 and the battery 70. Therefore, when a high level signal is output from the output port _b2 , both solenoids Su2 and Su3 are excited. However, when the solenoid S1 of the electromagnetic directional control valve V1 for hydraulic cylinder switching is not energized, only the energization of the solenoid Su3 is actually effective, and conversely, when the solenoid S1 is energized, the energization of the solenoid Su2 is Only excitation is effective.

A switching transistor 73 is connected to the output port _b3 , and the switching transistor 73 has solenoids Sd2 and Sd3 interposed in parallel with the battery 70 for closing and retracting the rods of the two electromagnetic directional control valves V2 and V3. Therefore, when a high-level signal is output from the output port _b3 , both solenoids Sd2 and Sd3 are energized, but as described above, the solenoid S1 of the electromagnetic directional control valve V1 for switching the hydraulic cylinder is not energized. In this case, only the excitation of the solenoid Sd3 is actually effective, and conversely, when the solenoid S1 is excited, only the excitation of the solenoid Sd2 is effective.

Regarding the operation of this device configured as above,
This will be explained below.

FIG. 8 is a flowchart showing the main routine of the control processing contents of the control section 74, and an outline will first be explained according to the flowchart of FIG.

When the power is turned on, the control unit 74 first performs various initial settings or defines each input port and output port. In this initial setting, for example, the ON time Ton of one unit when energizing each solenoid Su2, Su3, Sd2, Sd3 other than the hydraulic cylinder switching solenoid S1 is set to 10 ms, and the actual excitation is performed by setting this on time Ton to 4 ms. times continuous time ton
This includes processing such as initial setting to (40ms) or resetting (=0) all of the flags described later.

Here, the drive control of the solenoids Su2, Su3, Sd2, and Sd3 other than the switching solenoid S1 will be explained with reference to the flowchart shown in FIG. 9 showing the details thereof.

Excitation of solenoids Su2, Su3, Sd2, Sd3, etc. is performed in on-time Ton (10ms) units, and the on-time
Every time Ton elapses, interrupt processing is checked, etc. Then, when this is repeated four times, that is, the initially set time ton (=Ton×4) has elapsed, the solenoids Su2, Su3, Sd2, Sd3, etc. are demagnetized. After this, if the off time toff is set to 0, the next process is performed immediately (in most cases, the same solenoids Su2, Su3, Sd2, Sd3, etc.
ton=Ton×4) is performed,
In addition, if the off time toff is not 0, check the interrupt processing, etc. until the time toff elapses, wait for the off time toff to elapse, and then start the next process (in many cases, the same process is performed again). Solenoid Su2,
A process of exciting Su3, Sd2, Sd3, etc. over a period of time ton=Ton×4 is performed.

Therefore, when the off time toff is set to 0, if the excitation of solenoids Su2, Su3, Sd2, Sd3, etc. is instructed, each of these solenoids will be excited almost continuously, and the cylinder speed will change. is the fastest. In other words, when "speed" is selected by the cylinder speed changeover switch 64, the off time toff is set to zero.
Conversely, when the off time toff is not 0, if the excitation of solenoids Su2, Su3, Sd2, Sd3, etc. is instructed, each solenoid will be intermittently excited, and the cylinder speed will be the same as when the off time toff is 0. It will be slower than usual. In other words, the greater the off time toff, the slower the cylinder speed. Specifically, when the cylinder speed "medium" is selected by the cylinder speed changeover switch 64, the off time toff is set to four times the on time Ton, and when the cylinder speed is selected "slow", the off time toff is set to four times the on time Ton. In this case, the off time toff is set to 12 times the on time Ton.

Therefore, solenoids Su2, Su3, Sd2, Sd3
etc. are continuously energized when the cylinder speed is "fast", and when the cylinder speed is "medium", the energization and demagnetization are 40ms.
In the case of "slow", excitation for 40 ms and demagnetization for 120 ms are repeated and excitation is performed intermittently.

When the initial settings as described above are completed, the control unit 74
checks the mode switch 61. As a result of checking the mode switch 61, if the automatic mode is selected, control is performed to maintain the loading platform 20 horizontally regardless of the inclination of the carrier body. That is, the control section 74 checks the cylinder speed changeover switch 64 and sets the above-mentioned off time toff. As described above, this process sets the off time toff to 0 when the cylinder speed selected by the cylinder speed changeover switch 64 is "fast", and to 4 times the on time Ton when the cylinder speed is "medium".
i.e. 40ms, or 12 of the on time Ton in the case of "slow"
In other words, the time is set to 120ms.

Next, the control unit 74 controls the detected value RO of the rear position sensor 52 that detects the relative inclination angle between the upper frame 40 to which the loading platform 20 is attached and the sub frame 30, and
The detected value FO of the front position sensor 51 which detects the relative inclination angle between
(The detection range of the rear position sensor 52 is 0° to +
Since the range is 60°, if RO≦0°, the upper frame 4
0 and the sub frame 30 are parallel), or the front position sensor 51
The detected value FO is FO≧0° (the detection range of the front position sensor 51 is from 0° to -15°, so
FO≧0° means that the sub frame 30 and the main frame 10 are parallel) is automatically controlled so that the loading platform 20 is maintained parallel to the main body only when either of the following conditions holds true: otherwise, in other words, the rear position sensor 52 and the front position sensor 5
When the absolute values of both detected values RO and FO of 1 are larger than 0° (in the direction in which the upper frame 40 is separated from the sub frame 30, and in the direction in which the sub frame 30 is separated from the main frame 10) (if both are rotated), automatic control will not be performed and
The process returns to the step of checking the mode switch 61.

Therefore, in order to perform this automatic mode, it is necessary to manually set the rotation angle of either the upper frame 40 or the sub-frame 30 to 0°.

Now, if it is detected in the step of checking the mode switch 61 that the manual mode is selected, the control section 74 checks the loading platform switch 62. And the loading platform switch 6
2 is operated in the "up" (or "down") direction, set the up/down flag UD (UD=1)
After that, proceed to the manual raising subroutine (or manual lowering subroutine) to raise the loading platform 20 forward, that is, in the order of a → b → c in Figure 4 (or lower it forward, that is, in the order of c → d → a in Figure 4). ) and reset the elevation flag UD at the end of this subroutine (UD = 0).
Then, the process returns to the step of checking the loading platform switch 62.

On the other hand, if the loading platform switch 62 is not operated in either "up" or "down" mode in the manual mode, the vibration switch 65 may be instructed to vibrate the loading platform 20, so the control unit 74 Do that check. That is, first, the control section 74 checks the state of the vibration flag V, which is set when vibration of the loading platform 20 is instructed, and if it is set (V=1), it immediately resets it again (V=1). 0), the operation state of the mode switch 61 is checked and then the process proceeds to a step of checking whether the vibration switch 65 is turned on. This is done to give priority to the vibration operation of the loading platform 20 over the mode change by operating the mode switch 61. And vibration switch 6
5 is not turned on, the vibration flag V is reset and the mode switch 61 is turned on.
Returning to the step of checking, if the vibration switch 65 is turned on,
The program proceeds to a vibration subroutine for controlling the vibration of the loading platform 20, and after completing this subroutine, returns to the step of setting the vibration flag V and checking the loading platform switch 62.

Therefore, while the vibration switch 65 is turned on in the manual mode, the mode switch 61 cannot be operated to switch to other automatic modes or parallel modes.

When the parallel mode is selected by the mode switch 61, the control unit 74 sets the rotation angles of the upper frame 40 and the sub-frame 30 to 0°, so that the loading platform 20 is parallel to the main body (the state shown in FIG. 4a). ), and in this state the lift switch 63 lifts the loading platform 2.
When there is an instruction to lift up the loading platform 20, the loading platform 20 is raised and lowered (as shown in FIG. 4e).

First, the control section 74 checks whether the lift switch 63 is in the off state. In order to prevent danger and prevent cargo from collapsing, the loading platform 20 is raised and lowered by setting the rotation angles of both the upper frame 40 and the sub-frame 30 to 0° and keeping the loading platform 20 parallel to the main body (see Fig. 4). This is because the process is performed after the state (a) is established. If the lift switch 63 is off, the control unit 74 sets the rotation angles of both the upper frame 40 and the sub-frame 30 to 0°, proceeds to a parallel subroutine to make the loading platform 20 parallel to the main body, and ends this subroutine. After reading the setting value L of the lift switch 63 again, the process proceeds to a lift subroutine for raising and lowering the loading platform 20 parallel to the main body, and after completing this lift subroutine, the process returns to the step of checking the mode switch 61.

Next, automatic subroutines will be explained. As mentioned above, this automatic subroutine is a subroutine for controlling the loading platform 20 so that it is always horizontal with respect to the main body, regardless of the inclination state of the main body, when the automatic mode is selected by the mode switch 61. be. FIG. 10 is a flowchart showing the contents of this automatic subroutine.

As mentioned above, when the automatic mode is selected by the mode switch 61, the cylinder speed is set by the cylinder speed changeover switch 64, and the detection values RO and FO of either the rear position sensor 52 or the front position sensor 51 are set. 0°,
That is, if the upper frame 40 and the sub-frame 30 or the sub-frame 30 and the main frame 10 are parallel, this automatic subroutine is executed.

First, the control unit 74 detects the detected value of the loading platform sensor 53.
NO is read, but if the clutch sensor 54 is on, that is, if the state of the transport vehicle changes from a running state to a stopped state or vice versa,
Processing is not started until one second has passed after the clutch sensor 54 is turned off. Now, when the process is started by turning off the clutch sensor 54, the control section 74 performs control according to the detected value NO of the loading platform sensor 53. That is, when the detection value NO of the loading platform sensor 53 is within the range of ±1°, the loading platform 20 is horizontal, specifically, the main frame 10 and the sub frame 30 are parallel, and the secondary frame 30 and the upper frame 40 are parallel.
Assuming that they are parallel to each other (the state shown in FIG. 4a), no control is performed. However, for example, if the detected value NO of the loading platform sensor 53 is larger than +1° (the front part of the loading platform 20 is higher than the rear part, that is, the front is raised),
If the angle is greater than +4°, an automatic lowering subroutine is executed to automatically lower the front part of the loading platform 20 relatively quickly, and if the angle is greater than +1° but less than +4°, Processes a forward lowering speed limiting subroutine for lowering the front portion of the loading platform 20 relatively slowly. Conversely, if the detection value NO of the loading platform sensor 53 is smaller than -1° (the rear of the loading platform 20 is higher than the front, that is, the front is lowered) and smaller than -4°, the An automatic lift subroutine is executed to automatically raise the front part relatively quickly, and if the angle is less than -1° but more than -4°, the front part of the loading platform 20 is raised relatively slowly. Performs processing of the forward speed limit subroutine to increase the speed.

FIG. 11 shows a flowchart of the automatic lowering subroutine, and FIG. 12 shows a flowchart of the automatic raising subroutine.

The automatic lowering subroutine is a process that is performed when the loading platform 20 is in a raised state with respect to a horizontal plane. This automatic lowering subroutine is started by first reading the detection value RO of the rear position sensor 52, and if the detection value RO of the rear position sensor 52 is not 0°, that is, the upper frame 40 is lower than the sub frame 30. If they are separated in the forward lifting direction, the solenoid Sd3 is energized to move the piston rod 43R of the forward lifting hydraulic cylinder 43.
the upper frame 40 and the sub frame 30.
The loading platform 20 is rotated in a forward downward direction (towards a horizontal position) by rotating downward in a forward downward direction, that is, in a direction approaching the sub-frame 30 to bring the two closer together. On the other hand, when the detection value RO of the rear position sensor 52 is 0°, the upper frame 40 as described above is moved to the sub frame 3.
Since it is impossible to control the rotation downward in the direction approaching 0, the detected value FO of the front position sensor 51 is read and this is the rotation limit of 0°.
If it is smaller, the solenoids S1 and Su2 are energized to advance the piston rod 32R of the hydraulic cylinder 32 for forward lowering, and the sub frame 30 is rotated upward and downward relative to the main frame 10, thereby separating the two. By this, the loading platform 20 is rotated in the forward downward direction (the direction approaching the horizontal plane).

In contrast, the automatic lift subroutine
This is a process performed when 0 is in a forward-down state with respect to the horizontal plane. This automatic lift subroutine begins with the detection value of the front position sensor 51.
It starts by reading FO, and if the detected value FO of this front position sensor 51 is not 0°,
In other words, when the sub frame 30 is tilted forward and downward with respect to the main frame 10, the loading platform 20 is tilted forward and downward from the horizontal plane, and the detected value FO of the front position sensor 51 is -15°, the If the subframe 30 is rotated in the forward/downward direction with respect to the main frame 10, there is a risk of the cargo collapsing, so no control is performed. However, if the detected value FO of the front position sensor 51 is greater than 0° and less than 15°, the solenoid S1 and Sd
2 is excited and the piston rod 32R of the hydraulic cylinder 32 for forward lowering is moved back and forth, thereby rotating the sub frame 30 in the forward upward direction with respect to the main frame 10, bringing the two closer together, and moving the loading platform 20 in the forward upward direction. (toward the horizontal plane). On the other hand, when the detected value FO of the front position sensor 51 is 0°, the sub frame 3 as described above
Since it is impossible to control the rear position sensor 5 to approach the main frame 10, the control section 74 controls the rear position sensor 5.
2 is read, and if it is less than +30°, the solenoid Su3 is energized, the piston rod 43R of the hydraulic cylinder 43 for forward lifting is advanced, and the upper frame 40 is rotated in the forward upward direction relative to the sub frame 30. By moving them, the two are separated, and the loading platform 20 is rotated in the forward upward direction (the direction toward the horizontal plane). At this time, if the detection value RO of the rear position sensor 52 is greater than +30°, the control is not performed because there is a risk of the load collapsing or the like.

The front raising speed limit subroutine and the front lowering speed control subroutine are used, for example, to set the rotation limit of the sub frame 30 toward the main frame 10 (when the detected value FO of the front position sensor 51 is (approaching 0° from the value of ) or the sub-frame 30 of the upper frame 40
As the rotation speed to the side approaches the limit (the detection value RO of the rear position sensor 52 approaches 0° from a positive value), the rotation speed (specifically, the hydraulic cylinder 3
This is a process in which the advancing and retracting speeds of the piston rods 32R and 43R of 2 and 43 are performed relatively slowly, and the solenoid Su2,
Off time toff during excitation of Su3, Sd2, Sd3, etc.
This is done by increasing .

FIG. 13 is a flowchart showing the processing contents of the forward lowering speed limiting subroutine. In this subroutine, first, the state of the parallel flag set in the parallel mode parallel subroutine described later is checked. Then, if the parallel flag is not set, the detection value NO of the loading platform sensor 53 is read, and if the parallel flag is set,
The detected value RO of the rear position sensor 52 is read and this value is replaced with NO. Next, check the cylinder speed changeover switch 64, and if "slow" is selected as the cylinder speed, the off time
After setting toff to 12 times the on time Ton, and setting the off time toff to 4 times the on time Ton if "medium" or "fast" is selected as the cylinder speed, set the loading platform sensor 53 (or , until the detection values NO and RO of the rear position sensor 52) become 2 degrees or less when "slow" is selected as the cylinder speed, and when "medium" or "fast" is selected as the cylinder speed. Repeat the process of the automatic descent subroutine described above until the angle reaches 3°. In addition, if the cylinder speed is "medium",
In the case of "speed", if the detection values NO and RO of the loading platform sensor 53 (or rear position sensor 52) are 3 degrees or less and up to 2 degrees, the off time toff is the on time Ton.
The cylinder speed is set to 12 times that of the actual cylinder speed, resulting in a somewhat slow cylinder speed. When the detection values NO and RO of the loading platform sensor 53 (or rear position sensor 52) are 2 degrees or less, the off time toff is 22 times the on time Ton regardless of the cylinder speed selection by the cylinder speed changeover switch 64. is set, the cylinder speed is made relatively slow and the automatic lowering subroutine is processed, and the process ends when the detection values NO and RO of the loading platform sensor 53 (or rear position sensor 52) become 1° or less. do. Finally, if the parallel flag is set, the rear position sensor 52
NO is replaced as the detected value RO.

On the other hand, the flowchart shown in FIG.
(or detection value of rear position sensor 52)
The process is basically the same as the forward lowering speed limiting subroutine described above, except that NO approaches 0° from positive in the forward lowering speed limiting subroutine, whereas it approaches 0° from negative, so the explanation will be omitted. do.

In this way, in the front lowering speed limiting subroutine and the front raising speed limiting subroutine, the loading platform sensor 53
As the detected value NO approaches 0°, in other words, as the loading platform 20 becomes horizontal, each solenoid
Since the off time toff is set longer than the on time Ton of Su2, Su3, Sd2, Sd3, etc., the piston rod 32R of the hydraulic cylinder 32, 43,
43R is advanced and retracted more slowly, and therefore the loading platform 20 is rotated more slowly.

Next, control in manual mode will be explained.

When the manual mode is selected by the mode switch 61, the control section 74 next selects the loading platform switch 6.
Check 2. At this time, if the loading platform switch 62 is operated to the "up" side, the up/down flag is
UD is set and the manual lift subroutine is processed, thereby controlling the lift of the loading platform 20. If the loading platform switch 62 is operated to the "down" side, the lift flag UD is set and manual lowering is performed. Subroutine processing is performed, thereby controlling the lowering of the loading platform 20, and the elevation flag UD is reset after each subroutine is completed.

FIG. 15 is a flowchart showing the processing contents of the manual ascending subroutine, and FIG. 16 is a flowchart showing the processing contents of the manual descending subroutine.

In the manual raising subroutine, the control unit 74 first reads the detected value RO of the rear position sensor 52, and until this value reaches 60°, that is, the upper frame 40 to which the cargo platform 20 is attached is moved to the sub frame 30.
The solenoid Su3 is rotated forward and upward in the direction away from the solenoid Su3, and the solenoid Su3 is energized until it reaches its rotation limit. After that, the control unit 74 reads the detected value FO of the front position sensor 51, and the solenoid S1,
Excite Su2.

In other words, when raising the loading platform 20 in manual mode, the upper frame 40 to which the loading platform 20 is attached is first rotated in the forward upward direction away from the sub-frame 30 to its rotation limit and tilted. After that, the sub frame 30 is rotated forward and downward to the rotation limit of -15 degrees in the direction away from the main frame 10, and as a result, the loading platform is rotated at 45 degrees.
The angle of inclination is

On the other hand, in the manual lowering subroutine, the control section 74 first detects the detected value of the rear position sensor 52.
First read RO, and then operate the solenoid Sd3 until it reaches 0°, that is, until the upper frame 40 to which the loading platform 20 is attached is rotated forward and downward in the direction approaching the sub-frame 30 and the two become parallel.
Excitation is performed. After that, the control unit 74 reads the detected value FO of the front position sensor 51 until it reaches 0°, that is, the position of the sub frame 30
The solenoid S rotates forward and downward in the direction approaching the main frame 10 until the two become parallel.
1. Excite Sd2.

In other words, when lowering the loading platform 20 in manual mode, the upper frame 40 to which the loading platform 20 is attached is first rotated forward and downward until it approaches and becomes parallel to the sub-frame 30, and then the upper The sub-frame 30, which has become parallel to the frame 40, approaches the main frame 10 and is rotated in the forward upward direction until it becomes parallel. By the way, in the manual mode, by operating the vibration switch 65, it is possible to vibrate the loading platform 20, that is, to repeatedly move the loading platform 20 up and down. This operation
For example, this is done when scattering earth and sand placed on the loading platform 20 while moving the transport vehicle slowly.
The vibration subroutine processing when controlling the vibration of the loading platform 20 by the vibration switch 65 will be described below with reference to the flowchart of FIG. 17 showing its contents. The vibration control of the loading platform 20 is performed by moving the upper frame 40 up and down with respect to the sub-frame 30 using a front-lifting hydraulic cylinder 43.

First, the control unit 74 reads the detected value RO of the rear position sensor 52, and if this is less than +5°, this vibration subroutine is not performed.
This is because, as will be described later, the vibration of the loading platform 20 due to the vibration subroutine is performed within a range of 5° downward from the current position of the loading platform 20, so that the upper frame 40 is relative to the sub-frame 30. +
This is because if the loading platform 20 is not rotated by 5 degrees or more, there is no room to move the loading platform 20 up and down.

On the other hand, the detection value FO of the rear position sensor 52 is
In the case of 57 degrees or more, the vertical movement of the loading platform 20 is performed within a range of 5 degrees downward from +60 degrees, which is the rotation limit of the upper frame 40 with respect to the sub frame 30.

Now, the detected value of the rear position sensor 52
If RO is greater than +5° and less than +57°,
First, the off time toff is set to 0, and the solenoid Sd
3 is excited and the upper frame 40 becomes the sub frame 3.
It is rotated forward and downward in a direction approaching zero.
During this time, the control unit 74 reads the detected value of the rear position sensor 52 and sets it as R1, which is the value obtained by subtracting 5 degrees from the detected value RO before excitation of the solenoid Sd3.
Continue energizing solenoid Sd3 until it reaches RO-5. In other words, the upper frame 40 is rotated forward and downward by 5 degrees, that is, in a direction approaching the sub-frame 30. However, when the detection value R1 of the rear position sensor 52 reaches 0°, the solenoid Sd3 is demagnetized to stop the rotation of the loading platform 20 in the direction approaching the sub-frame 30. Then, when the upper frame 40 to which the loading platform 20 is attached rotates downward toward the sub-frame 30 and approaches the sub-frame 30 by 5 degrees, the solenoid Sd3 is demagnetized, and then the solenoid Su3 is energized. During the excitation of the solenoid Su3, the control unit 74 reads the detected value of the rear position sensor 52 and sets it as R2, which causes the upper frame 40 to first move downward in the forward direction, that is, in the direction approaching the sub frame 30. The solenoid Su3 is energized until it becomes equal to the detection value RO of the rear position sensor 52 before being moved, in other words, the upper frame 4
0 is rotated upward in the direction away from the sub frame 30.

With the above control, the loading platform 20 has made one reciprocation between the initial position and a position 5 degrees below the initial position, that is, a position 5 degrees closer to the sub frame 30. During this period, vibration control of the loading platform 20 is repeatedly performed.

Next, the relative rotation angle between the upper frame 40 and the sub-frame 30 is +57° or more (however, +60° or less)
The control in this case will be explained. In this case,
First, the control unit 74 sets the off time toff to 0, excites the solenoid Sd3, and rotates the upper frame 40 forward and downward in a direction toward the sub-frame 30. During this time, the control unit 74 reads the detected value of the rear position sensor 52 and sets it as R3, and continues to excite the solenoid Sd3 until this value becomes RO-5, which is the value RO-5 obtained by subtracting 5 degrees from the detected value RO before the excitation of the solenoid Sd3. In other words, the upper frame 40
It is rotated downward by 5 degrees forward. And loading platform 20
When the upper frame 40 to which the is attached rotates downward toward the sub-frame 30 and approaches it by 5 degrees, the control section 74 demagnetizes the solenoid Sd3 and then energizes the solenoid Su3. During the excitation of the solenoid Su3, the control unit 74 controls the rear position sensor 52.
This is the upper frame 40.
energizes the solenoid Su3 until its upper limit of rotation, that is, the rotation angle with respect to the sub frame 30 reaches +60°,
In other words, the upper frame 40 is rotated upward in a direction away from the sub frame 30.

With the above control, the upper frame 40 to which the loading platform 20 is attached is rotated 5° from the initial position to the sub frame 3.
0, and then upwardly rotated in a direction away from the sub frame 30 to a position where the rotation angle with the sub frame 30 is +60°, which is the upper limit of the rotation. Then, if the vibration switch 65 continues to be operated, the upper frame 40 will rotate at a rotation angle of +
It is repeatedly moved up and down between the 60° position and a position 5° closer to the sub-frame 30.

Next, the parallel mode and the lift control that can be operated in the parallel mode will be explained.

When the parallel mode is selected with the mode switch 61, even if the loading platform 20 is not parallel to the carrier body, the upper frame 40 and the sub-frame 30 are parallel, and the sub-frame 30 and the main frame 10 are are parallel to each other, and the loading platform 20 becomes parallel when it is closest to the carrier body (the state shown in FIG. 4a). Then, when the lift switch 63 is operated, the loading platform 20 is raised and lowered relative to the transportation vehicle body while maintaining the parallel state between the loading platform 20 and the transportation vehicle body (the upper limit of this is the upper frame 40 as shown in FIG. 4e). The rotation angle of the sub frame 30 with respect to the main frame 10 is +15 degrees, and the rotation angle of the sub frame 30 with respect to the main frame 10 is -15 degrees. This operation is very effective, for example, when loading and unloading cargo with the loading platform of another truck or the like, because it allows the height positions of both loading platforms to be made the same.

Now, as described above, when the parallel mode is selected by the mode switch 61, the control section 74 checks whether the lift switch 63 is in the off state. If the lift switch 63 is in the OFF state, a parallel subroutine is executed to make the loading platform 20 parallel to the carrier body at the closest position. FIGS. 18a and 18b are flowcharts showing the processing contents of this parallel subroutine.

When the processing of the parallel subroutine is started, the control section 74 first sets the parallel flag H (=0).
The control section 74 then controls the front position sensor 5.
1 detection value FO and the detection value RO of the rear position sensor 52 are read, and if the detection value FO of the front position sensor 51 is -1° or more (however, 0° or less), the front flag FF is set (= 1) and
Also, the detection value RO of the rear position sensor 52 is +
Rear flag RF if less than 1° (but more than 0°)
is set (=1).

The subsequent processing is performed when both flags FF and RF are set (-1°≦FO≦0° and 0°≦RO≦+
1°, that is, the absolute values of both detected values FO and RO are both 1 or more), when one flag FF or RF is set and the other is reset (-1°≦FO≦0° and
RO>+1°, or FO<-1° and 0°≦RO≦+1°)
Alternatively, the execution is performed in four different cases: when both flags FF and RF are in the reset state (FO<-1° and RO>+1°).

First, when both flags FF and RF are set (-1°≦FO≦0° and 0°≦RO≦+1°), the upper frame 40 is parallel to the subframe 30, and the subframe 30 is parallel to the main frame. It is considered to be parallel to 10,
This control is not performed because the loading platform 20 is not lifted up from the main body and the loading platform 20 and the main body are parallel (the state shown in FIG. 4a).

When front flag FF is set and rear flag RF is reset (-1°≦FO≦0°, RO>+1°)
Since the sub-frame 30 is parallel to the main frame 10, only the upper frame 40 to which the loading platform 20 is attached is rotated forward and downward in the direction approaching the sub-frame 30, so that it becomes parallel to the sub-frame 30. do it. Therefore, if the detection value RO of the rear position sensor 52 is +4° or more, the control unit 74 directly excites the solenoid Sd3 until the detected value RO of the rear position sensor 52 reaches +4°, and moves the upper frame 40 toward the sub-frame 30 relatively quickly. If the detected value RO of the rear position sensor 52 is less than +4°, the front lowering speed limit subroutine is executed and the front part of the loading platform 20 is lowered relatively slowly in the forward downward direction. Rotate.

Conversely, when the front flag FF is reset and the rear flag RF is set (FO≦-1°, 0°≦RO
≦+1°), the upper frame 40 is
0, the sub frame 30 is rotated in the direction approaching the main frame 10, and the main frame 1
It should be parallel to 0. Therefore, the control section 74
The detection value RO of the front position sensor 51 is -
If the angle is less than 4 degrees, the solenoids S1 and Sd2 are directly excited until the temperature reaches -4 degrees, and the sub frame 30 is relatively quickly rotated downward in a direction approaching the main frame 10, and the front position sensor 51 detects the position. value
If RO is greater than or equal to -4° and less than 0°, the forward raising speed limit subroutine is processed and the sub frame 30 is relatively slowly rotated downward toward the main frame 10, thereby moving the front of the loading platform 20. Rotate the part relatively slowly in the forward and upward direction.

When both flags FF and RF are in the reset state (FO<-1°, RO>+1°), the processing is as shown in FIG. 18b. In this case as well, there are four cases: when the absolute values of FO and RO are both greater than +4°, when both are less than +4°, and when one is less than 4° and the other is greater than +4°. will be processed.

First, the detection value of the front position sensor 51
If FO is -4° or more and the detection value RO of the rear position sensor 52 is +4° or less, 1 is shown in Fig. 18b.
Processing proceeds to step 8b. This 18
In the process after b, the control unit 74 performs the forward lowering speed limiting subroutine and the forward increasing speed limiting subroutine once each, and then controls both position sensors 5.
The process returns to the step of reading the detected values FO and RO of 1 and 52. Therefore, the above processing is repeated until either the absolute value of the detection values RO and FO of both position sensors 51 and 52 becomes +4° or less (RO≧4° or FO≦4°), and the upper frame is 40 is relatively slowly rotated and lowered in a direction approaching the subframe 30, and the subframe 30 is rotated relatively slowly in a direction approaching the main frame 10.

When the detected value FO of the front position sensor 51 is smaller than -4° and the detected value RO of the rear position sensor 52 is less than +4°, the control unit 74 first excites the solenoids S1 and Sd2 to control the main frame. After the sub frame 30 is rotated downward in a direction approaching the main frame 10 until the relative rotation angle between the sub frame 10 and the sub frame 30 becomes +4° or less, the process proceeds to step 18b described above.

If the detected value FO of the front position sensor 51 is smaller than -4° and the detected value RO of the rear position sensor 52 is larger than +4°, the control unit 74 first changes the detected value FO of the front position sensor 51 to
Calculate the value of 1/2 and set this value as Y, and this value Y
In other words, the solenoids S1 and Sd2 are energized until the detection value FO of the front position sensor 51 reaches -4°, and the sub frame 30
is rotated downward in a direction approaching the main frame 10 (however, if the value Y is −4° or more from the beginning, this process is omitted). In this way, the value Y becomes −
When the value falls below 4° (the detected value FO of the front position sensor 51 is −8°), the value Y is replaced with the detected value NO of the loading platform sensor 53, and the process shifts to the forward raising speed limit subroutine. After this forward speed limit subroutine ends, the control section 74 controls the rear position sensor 52.
Calculate the value of 1/2 of the detected value RO of , set this value as Z, and keep the solenoid Sd3 until this value Z reaches +4°, in other words, until the detected value FO of the rear position sensor 52 reaches +8°. Excite the upper frame 4
0 is rotated downward in a direction approaching the sub-frame 30 (however, if the value Z is +8° or less from the beginning, this process is omitted). In this way, the value Z is +8° (the detection value RO of the rear position sensor 52 is +8°).
8°) or less, the value Z is replaced with the detected value NO of the loading platform sensor 53 and the process moves to the forward lowering speed limit subroutine.

Through the above series of processes, the absolute values of the detection values FO and RO of both position sensors 51 and 52 are less than +8° (FO≧−8°, RO≦+8°).

Next, the control section 74 controls the front position sensor 5.
If the detected value FO of 1 is smaller than -4°, the solenoids S1 and Sd2 are energized until the detected value FO becomes -4°, the sub frame 30 is rotated downward in the direction of approaching the main frame 10, and then the front Processes the raising speed limit subroutine. Further, if the detected value RO of the rear position sensor 52 is greater than +4°, the control unit 74 controls the solenoid Sd until the detected value RO of the rear position sensor 52 reaches +4°.
3 is excited to connect the upper frame 40 to the sub frame 30.
After that, the forward speed limit subroutine is executed.

Therefore, when the parallel subroutine process is started, if the detected value RO of the rear position sensor 52 is greater than +4° and the detected value FO of the front position sensor 51 is less than -4°, that is, both If the absolute value is greater than 4°, the upper frame 40 and the sub-frame 30 are first rotated downward as necessary so that the absolute values of both detected values RO and FO are 8°, and then Adjust the upper frame 4 as necessary so that the absolute values of both detected values RO and FO are 4°.
0 and the auxiliary frame 30 are rotated downward, and then the front raising speed limiting subroutine and the front lowering speed limiting subroutine are repeated to gradually bring the loading platform 20 into a state parallel to the carrier body.

Now, after the parallel subroutine has been processed as described above, by setting the height position of the loading platform 20 with respect to the main body using the lift switch 63, it is possible to control the lifting and lowering of the loading platform 20. The control contents of the lift subroutine for raising and lowering the loading platform 20 are shown in the flowchart of FIG.

First, the control section 74 resets the flags DRP and DFR, and then reads the set value L of the lift switch 63, the detected value RO of the rear position sensor 52, and the detected value FO of the front position sensor 51, respectively. Then, the value dr (= L -RO) that subtracts the detection value RO of the rear Podisillon sensor 52 from the set value L of the lift swit 63, and the set value of the lift suits 63 to the front Posesisillon sensor 5.
A value DF (=L−FO) obtained by subtracting the detected value FO of 1 is calculated.

When DR<DF and DF>1°, control for lifting up the loading platform 20 is executed by energizing the solenoids S1 and Su2 and rotating the sub frame 30 upward in a direction away from the main frame 10. (However, when DF≦2°, the off-time toff is set to 22 times the on-time Ton and relatively slowly), and when DR<DF and DF<-1°, the loading platform 20
The control for lifting down is solenoid S1.
This is done by exciting Su2, rotating the sub frame 30 in the direction approaching the main frame 10, and rotating the rear part of the loading platform 20 downward (however, DF≧
In the case of −2°, the off time toff is 22 of the on time Ton.
(relatively slowly as double) and return to −1°≦DF≦
In the case of 1°, only the flag DFR is set without excitation control of the solenoid, and then the flag DRP is set.
If it has been set, the process returns to step 2, and if it has been reset, the control ends.

On the other hand, if DR≧DF, the value DF is used instead of the value DR in the above process, so
The solenoids Su3 and Sd3 are energized to rotate the upper frame 40 in a direction away from or toward the sub-frame 30, thereby raising and rotating the front part of the loading platform 20 to lift up the loading platform 20, or to raise the front of the loading platform 20. Control is performed to lift down the loading platform 20 by rotating the lower part. Then, when the loading platform 20 passes horizontally, the value DF (or value DR) becomes −
When it reaches 1°, set the flag DFR (or DPR) and return to the previous step. After this, the loading platform 20 is lifted (or lifted down) by rotating the opposite side of the loading platform 20, and the loading platform 20 passes horizontally again to reach the value DR (or value DF)
When the angle becomes -1°, the flag DFR (or DPR) is set, so the process of this lift subroutine is temporarily terminated. Then, when the loading platform 20 is lifted up to the height position set by the lift switch 63, DR=0 and the process ends. Therefore, in this lift subroutine,
Initially, the angle may be 2 degrees, but normally the front and rear portions of the loading platform 20 are raised alternately by 1°, and the entire loading platform 20 is lifted up, or lowered, and the entire loading platform 20 is lifted down.

〔effect〕

As detailed above, according to the present invention, it is possible to maintain the loading platform horizontally regardless of whether the carrier body is tilted forward or backward; however, this control is possible only when the upper frame is parallel to the sub frame. or the secondary frame is parallel to the main frame. Therefore, the control device can perform subsequent control based on the sensor that detects the rotation angle between the parallel frames (detected value = 0°), making control easier and reducing the load on the control device. be done.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention.
The figure is a schematic perspective view of a carrier equipped with the loading platform posture device of the present invention, Figure 2 is a side sectional view seen from the right side, Figure 3 is a plan view of Figure 2, and Figure 4 is a carrier vehicle. 5 is a schematic diagram of the operation panel, FIG. 6 is a hydraulic circuit diagram of the main parts of the transport vehicle, and FIG. 7 is a block diagram of the control circuit of the proposed device.
Fig. 8 is a flowchart of the main routine showing the processing contents of the control section, Fig. 9 is a flowchart showing the control method of the solenoid for driving the hydraulic cylinder,
Figure 10 is a flowchart of the automatic subroutine.
Figure 11 is a flowchart of the automatic lowering subroutine, Figure 12 is a flowchart of the automatic raising subroutine, Figure 13 is a flowchart of the forward lowering speed limiting subroutine, Figure 14 is a flowchart of the forward raising speed limiting subroutine, and Figure 15 is a flowchart of the forward lowering speed limiting subroutine. Figure 16 is a flowchart of the manual up subroutine, Figure 16 is a flowchart of the manual lowering subroutine, Figure 17 is a flowchart of the vibration subroutine, Figure 18 is a flowchart of the parallel subroutine, and Figure 19 is a flowchart of the lift subroutine. be. S1, Su2, Su3, Sd2, Sd3...Solenoid, 3...Clutch lever, 6...Operation panel, 10...
Main frame, 11... Crawler, 12... Chassis,
20... Loading platform, 30... Sub frame, 32... Hydraulic cylinder, 40... Upper frame, 43... Hydraulic cylinder, 51... Front position sensor, 52... Rear position sensor, 53... Loading platform sensor, 61...
Mode switch, 62... Loading platform switch, 63... Lift switch, 64... Cylinder speed changeover switch, 64... Vibration switch, 74... Control unit.

Claims (1)

[Scope of Claim for Utility Model Registration] One end of the main frame in the front and back direction is pivotally supported by one end of the main frame equipped with the traveling device, and the other end of the main frame in the front and rear direction is movable up and down. a first sensor for detecting a rotation angle of the sub frame relative to the main frame; a second sensor for detecting the rotation angle of the upper frame with respect to the sub-frame, the end of which is configured to be movable up and down; and a second sensor for detecting the absolute angle of the loading platform attached to the upper frame with respect to the horizontal plane. and a third sensor, when an instruction to control the loading platform in a horizontal state is given according to the detection result of the third sensor, the second sensor controls the upper frame and the sub-frame. The control is started only when the sub frame and the main frame are detected to be parallel, or when the first sensor detects that the sub frame and the main frame are parallel to each other. A loading platform posture control device for a transport vehicle, which is characterized by: