JPS6331521Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a work machine horizontal control device suitable for puddling or field farming using an agricultural tractor.

When a paddy harrow consisting of a blade wheel and a leveling plate is attached to an agricultural tractor for plowing work, it is necessary to maintain the working machine (paddy harrow) in a horizontal position at all times, regardless of the rolling of the tractor itself. In order to meet this requirement, the present invention provides a level on the work equipment, and attaches a double-acting hydraulic cylinder to one of the left and right lift links that connect the lift arm and lower link to raise and lower the work equipment based on the signal from the level. For example, when the right end or left end of the work equipment is used as a reference, when the side opposite to the reference rises, it is lowered by hydraulic pressure, and when it descends, it is raised by hydraulic pressure. The end of the machine can be raised and lowered directly to keep the work machine in a horizontal position at all times.
Next, it will be explained with reference to the drawings.

In FIG. 1, which includes the left side portion of an agricultural tractor to which the present invention is applied, a suction port 3 of a pump 2 driven by an engine 1 is connected to a strainer 6 in a tank 5 through an oil line 4. The discharge port 7 is connected to the inlet of a diversion valve 9 via an oil passage 8, one outlet of the diversion valve 9 is connected to an inlet 12 of a main control valve 11 via an oil passage 10, and the other outlet of the diversion valve 9 is The outlet is oil line 13
It is connected to the inlet 15 of the rolling control valve 14 via the inlet 15 of the rolling control valve 14 . Among the outlets 16, 17, and 18 of the main control valve 11, the outlet 16 communicates with the tank 5 through an oil passage 20 having a slow return valve 19, the outlet 17 communicates with the tank 5 through an oil passage 21, The outlet 18 communicates through an oil passage 23 with a stop valve 22 to an operating chamber 25 of a hydraulic cylinder 24 for driving the lift arm. An oil passage 27 having a safety valve 26 branches off from the middle of the oil passage 23, and the other end of this oil passage 27 communicates with the tank 5. 28 is a hydraulic pressure outlet.

The piston 30 fitted in the hydraulic cylinder 24 engages with the lower end of the lift crank 32 via the rod 31, and the left end of the lift shaft 33 to which the upper end of the lift crank 32 is fixed is attached to the left lift arm 3.
4, a feedback arm 35 is attached, and the lift arm 34 connects to the left lower link 3 via a lift link 36 and a double-acting hydraulic cylinder 37.
It is connected to the center of 8. The front end (left side in the figure) of the lower link 38 is connected to a tractor main unit side bracket 40 via a pin 39 in the vehicle width direction, and the rear end is connected to a gear case 41. 42 is a rotor attached to the lower end of the gear case 41, 43 is a rotary cover that covers the rotor 42, 44 is a rear cover, and the rear cover 44 is connected to a hinge pin 45 in the vehicle width direction.
It is attached to the rotary cover 43 via.
The rotor 42 digs into uncultivated land 46 by a certain amount, and the rear end of the rear cover 44 elastically rests on the cultivated land 47 behind the rotor. 48 and 49 are pins in the vehicle width direction, 50 is a piston provided at the lower end of the lift link 36, and this piston 50 is connected to the hydraulic cylinder 3.
The upper and lower working chambers 51 and 52 are connected to inlets and outlets 55 and 56 of the rolling control valve 14 through oil passages 53 and 54, respectively.

A right lift arm 34' fixed to the right end of the lift shaft 33 is connected to a right lower link 38' via lift links 59 and 60 having turnbuckles 58 in the middle. The turnbuckle 58 has right-handed and left-handed screw holes on the top and bottom, into which the lift links 59 and 60 are screwed, and the lock nut 6
1 is integrated.

A feedback rod 62 for position control is connected to the lower end of the feedback arm 35 via a pin in the vehicle width direction, and the front end of the rod 62 is connected to the rear of the middle part of the control bar 63 (on the right side in the figure). They are in contact with each other and provide a fulcrum for the bar 63. A spool 6 is attached to the front of the lower end of the control bar 63.
4 is brought into pressure contact with the force of the spring 65 acting in the downward direction (reverse A direction), and the front surface of the upper end of the bar 63 comes into contact with the cam 67 of the control lever 66. 68 is a tension spring connected to the upper end of the bar 63.

A feedback rod 70 for depth control installed above the rod 62 has its front end opposed to the control bar 63 with a slight distance between the rods 62 and 62, and is supported slidably in the longitudinal direction by a guide mechanism (not shown). The rear end is engaged with the lower end of the arm 71. The upper end of the arm 71 is swingably supported by a pin 72 in the vehicle width direction, the front end of a wire 73 is connected to the middle part, the wire 73 extends rearward and downward from there, and the lower end is attached to the bracket 74 of the rear cover 44 in the vehicle width direction. Connected via directional pins.

The outlet 76 of the rolling control valve 14 communicates with the tank 5 through an oil passage 77, and a bypass oil passage 79 having a safety valve 78 connects the oil passages 13, 77.
The rolling control valve 14 includes a switching solenoid 80,
81, which are connected to a controller 84 via signal lines 82 and 83. The controller 84 has a built-in relay, and the signal line 8
5 and 86 to the level 87 of the rotary cover 43. 88 is a battery.

The illustrated spirit level 87 is of a mercury type as shown in FIG. and electrodes 90,9
0' is connected to ground, and signal lines 85 and 86 are connected to electrodes 89 and 89'. When the spirit level 87 is horizontal, the internal mercury 91 is in the center of the container, and neither the left nor the right electrodes are connected. However, when the left side of the rotary cover 43 is tilted lower, the mercury 91 moves to the left as shown by the arrow and connects the electrodes 89 and 90.

In FIG. 1, the rotor 42 is connected to the control lever 66.
This shows a neutral state in which the plowing work continues at the position indicated by , and since the rolling control valve 14 is in the neutral state, the length of the left lift link 36 (the cylinder 37 also plays the role of a lift link) is L. and the length L' of the right lift links 59, 60 are equal (L=L'). From this state, the control lever 66
When the control lever 63 is operated in the upward direction shown by arrow B, the control lever 63 rotates clockwise about the rod 62, and its lower end pushes the spool 64 in the upward direction shown by arrow A. As a result, the main control valve 11 is switched to the left in the figure, and until then the main control valve 11 is switched from the inlet 12 to the outlet 1.
The hydraulic oil that was flowing out to the 7 side has been changed from the inlet 12 to the outlet 1.
By switching to the 8 side, the oil is supplied to the working chamber 25 of the hydraulic cylinder 24 through the oil path 23, the lift arm 34 is raised, and the entire working machine is raised. At that time, the lengths L and L' of the lift links remain unchanged. As the lift arm 34 rises, the feed back block 6
2 moves backward, the spool 64 moves in the downward direction (reverse A
direction), thereby causing the lift arm 34 to move to the position indicated by the control lever 66.

When the left side of the rotary cover 43 becomes lower than the right side due to the rolling of the tractor body during work, the level 87 in FIG. The electrodes 89 and 90 are connected. This transmits a signal through line 85 to controller 84, which activates a relay to provide a raise signal from line 82 to solenoid 80. When the solenoid 80 is energized, the rolling control valve 14 switches in the upward direction (direction of arrow A) against the elasticity of the spring, and the inlet 15 closes to the inlet/outlet 55.
Since the inlet/outlet 56 is connected to the outlet 76, hydraulic pressure is supplied to the working chamber 51, the cylinder 37 rises relative to the piston 50 which is fixed in the vertical position, and the left side portion of the rotor 42 rises via the left lower link 38. . When the rotary cover 43 becomes horizontal, the mercury 91 separates from the electrodes 89 and 90 and returns to the neutral position shown in FIG. As a result, the rolling control valve 14 returns to the neutral state shown in FIG.
The oil pressure in the engine 2 is maintained, and the lift link length L is reduced to a constant value (L≠L'). When the left side portion of the rotary cover 43 rises relative to the right side portion, L increases due to the opposite operation, and in this way, the working machine maintains its posture as horizontal as possible.

During the rolling control described above, if the plowing depth H increases beyond a certain value, the depth control feedback rod 70 moves forward in the direction of the arrow due to the counterclockwise movement of the rear cover 44 with the pin 45 as the fulcrum. The spool 64 is pushed in the raising direction (arrow A), and hydraulic pressure is supplied to the working chamber 25 regardless of the position of the control lever 66, thereby raising the entire working machine. When the plowing depth H decreases and the rear cover 44 rotates clockwise about the pin 45, the rod 70 retreats in the direction of the opposite arrow and returns to the original position control state.

As explained above, according to the present invention, the spirit level 8 is placed at a suitable place on the working machine, for example, on the rotary cover 43.
7 is attached, and the rolling control valve 14 of the double-acting hydraulic cylinder 37 and the spirit level 87 are connected so that the work machine always maintains a horizontal position.
The inclination of the working machine can be directly and sensitively corrected regardless of the position of the working machine, and the horizontal control of the working machine is ensured. Also, since it is equipped with a depth control mechanism consisting of the rear cover 44, wires 73, feedback rod 70, etc., there is no risk of the plowing depth abnormally increasing or decreasing when maintaining the level of the work equipment, and the work equipment and tractor It is possible to prevent overload on. Moreover, since the depth control mechanism is fed back to the main control valve 11 for controlling lift arm elevation, no special control valve is required for depth control, and parts costs can be saved. In addition, in a general tractor, the turnbuckle 58 is attached to the middle of the right lift links 59, 60, and the left lift link is a rod that directly connects the lift arm 34 and the lower ring 38, so the turnbuckle 58 is attached to the middle of the left lift link. Alternatively, it is easy to interpose a double-acting hydraulic cylinder 37 at the end, and by using the double-acting hydraulic cylinder 37 and the right turnbuckle 58 in combination, the adjustment range becomes wide and appropriate control becomes possible.
Instead of the mercury type level 87, a ball type or hanging cone type (scale type) level can also be used.

There are also the following effects.

Hydraulic cylinder 37 and depth control are used so that during rolling control to extend the double-acting hydraulic cylinder 37, the work machine is raised by the depth control mechanism, and during rolling control to contract the hydraulic cylinder 37, the work machine is lowered by the depth control mechanism. Since the system is linked to the mechanism, the optimal plowing depth and horizontal position can always be achieved even when the tractor is tilted to the left or right.

That is, if the hydraulic cylinder 37 is installed on the left side and the right wheel falls into a depression during work and tilts to the right side (the opposite side to the cylinder 37), automatic rolling control will operate and the cylinder 3
7 expands. This alone would result in an excessive plowing depth, but since the depth control mechanism simultaneously raises the work implement, the plowing depth can be controlled to an appropriate plowing depth while maintaining a horizontal position.

Conversely, if the cylinder 37 is tilted to the left (the same side as the cylinder 37) during work, the cylinder 37 will contract. This alone would result in too small a plowing depth, but at the same time the working machine is lowered using depth control, so it is possible to obtain the appropriate plowing depth while maintaining a horizontal position.

[Brief explanation of drawings]

Fig. 1 is a structural diagram including the left side portion of an agricultural tractor to which the present invention is applied, and Fig. 2 is the same as Fig. 1.
It is a cross-sectional partial enlarged view. 14... Rolling control valve, 34... Lift arm, 36, 59, 60... Lift link, 37... Double acting hydraulic cylinder, 38... Lower link, 42... Rotor, 70... Feedback rod for depth control, 87... Level vessel.

Claims (1)

[Scope of utility model registration request] A double-acting hydraulic cylinder 37 is installed on one of the left and right lift links 36 that connect the lift arm 34 and the lower link 38, a level 87 is provided on the work machine, and the control valve 14 of the double-acting hydraulic cylinder 37 and the level 87 are installed. The work equipment is connected so that it always maintains a horizontal position, and is equipped with a depth control mechanism that detects the working depth of the work equipment and provides feedback to the main control valve 11 for controlling lift arm elevation, in addition to the hydraulic position control mechanism. The hydraulic cylinder 37 and the hydraulic cylinder 37 are arranged so that during rolling control to extend the double-acting hydraulic cylinder 37, the working machine is raised by the depth control mechanism, and during rolling control to contract the hydraulic cylinder 37, the working machine is lowered by the depth control mechanism. A work machine horizontal control device for an agricultural tractor, characterized in that it is linked with a depth control mechanism.