JPS6134763B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety mechanism for a hydraulic lifting device for controlling the lifting and lowering of a ground working machine such as a rotary connected to a power agricultural machine such as a tractor.

This type of hydraulic lift actuator operates a lift crank fixed to the lift shaft of a lift mechanism that suspends ground-based work equipment by moving a hydraulic piston in and out, which is controlled to supply and discharge pressure fluid from a hydraulic valve. The hydraulic valve has a structure that moves up and down by rotating the hydraulic valve, and the switching operation of the pressure fluid path in this hydraulic valve is performed by manually rotating the slider of the hydraulic valve using a ring mechanism, for example, by manually rotating a position lever. It is configured to control movement via. Since this lift crank approaches the cylinder case constituting the frame of the hydraulic lifting actuator near its upper limit, conventional methods have been used to limit the upper limit position of the lift crank. This was accomplished by providing a stopper to limit the operational rotation of the position lever and draft lever, and adjusting the mounting position of the stopper. However, since the position lever and draft lever are each linked to the slider of the hydraulic valve through a complicated link mechanism, both the protruding position of the hydraulic piston and the upper limit position of the lift crank can be adjusted. It is difficult to adjust the position of the stopper in relation to the operating positions of the position lever and the draft lever, and the actual situation is that this adjustment requires a considerable amount of time.

Therefore, the present invention controls the supply and discharge of pressure fluid to and from the hydraulic piston 6 by moving the slider 3 of the hydraulic valve 2 in and out. In a hydraulic lifting/lowering actuator configured to be rotated up and down by a pressure piston 6, a shaft 37 provided on the upper outer periphery of the hydraulic cylinder 4
from the opening edge of the hydraulic cylinder 4 to the hydraulic piston 6
, and a return arm 38 that is located on the slider 3 side and can come into contact with the spool arm 21 . An interlocking mechanism 42 is provided so that the return arm 38 side separates from the spool arm 21 when it comes into contact with the edge, and this interlocking mechanism 42 moves in the upward rotational direction near the upper limit of the lift crank 7. We propose a safety mechanism for a hydraulic lifting actuator configured to move the slider 3 in the direction in which the lift crank 7 stops in accordance with the movement of the moving hydraulic piston 6,
Thus, the present invention provides a safety mechanism in which adjustment work is easy and the above-mentioned interlocking operations are reliable.

Next, the specific structure will be explained based on one embodiment shown in the drawings. As shown in FIG. A slider 3 provided to move in and out of the hydraulic valve 2 back and forth is used to supply and discharge pressure fluid to and from the hydraulic cylinder 4 and to stop it. That is, if the slider 3, which is always biased by the spring 5 so as to protrude rightward from the hydraulic valve 2, is moved, for example, in the direction of the arrow A, the hydraulic piston 6 of the hydraulic cylinder 4 moves in the same direction. Pressure fluid is supplied from the hydraulic valve 2 to the hydraulic cylinder 4 so as to protrude to the right in the figure, and the connecting rod is fitted into the recess 6a formed in the skirt of the hydraulic piston 6 and the recess 7a of the lift crank 7, respectively. 43 is the hydraulic piston 6
, the lift crank 7 is pushed, and the lift arm 9 fixed to the lift shaft 8 is rotated upwardly so that a ground work machine (not shown) suspended from the lift arm 9 is lifted. It is composed of

Then, a draft lever 12 and a position lever 13 are attached to the double shafts 10 and 11 which are rotatably provided in the cylinder case 1, respectively, and crank pins 14 and 15 are fixed to one ends of these double shafts 10 and 11. , actuators 18 and 19 are attached to a draft link 16 and a position link 17 whose upper ends are pivotally connected to crank pins 14 and 15, respectively, and a spool arm 21 which is pivotally connected to the cylinder case 1 by a pin 20.
Actuators 18 and 19 are visible on the rear surface. A spring 22 stretched between the rotating tip of the position ring 17 and the cylinder case 1 projects from the middle part of the position link 17 to a cam 23 provided integrally with the lift crank 7. The pin 24 is always in contact with the position lever 13, for example, in the first position.
If the position link 17 is rotated in the direction of the arrow B in the figure, the position link 17 will rotate counterclockwise around the pin 24 that is in contact with the cam 23, and the lower end actuator 19 will move in the opposite direction of the arrow A. , since the slider 3 can be projected and moved in the same direction, the lift arm 9 is rotated downward in the clockwise direction. At the same time, the cam 23 also rotates clockwise, and the pin 24 that comes into contact with this cam 23 rotates the position link 17 clockwise around the crank pin 15, so that the lower end actuator 19 is moved to the spool arm 21. The slider 3 is pushed back in the direction of the arrow A through the slider 3, and the hydraulic valve 2 becomes a neutral position, stopping supply and discharge of pressure fluid and stopping the downward rotation of the lift arm 9. There is.

In addition, the draft adjustment mechanism for keeping the tilling resistance of the ground work machine constant is a pin 2 attached to the cylinder case 1.
A draft rod 27 is pivotally connected to the upper end of a bracket 26 which is pivotally connected at 5, and a spring 28 is interposed between the draft rod 27 and the cylinder case 1. A pin 30 is engaged with the lower end of the arm rod 29 fixed to the front end of the draft rod 27, and the tip of the rod 32 is engaged with the pin 31 that is engaged with the draft link 16. 30, a spring 33 is interposed between the pins 31 and 30, and the front end of the top link 34 of the coupling device that connects the ground work machine to the power agricultural machine is connected to the bracket 26 with the pin 35. Pivotally mounted, position lever 1
3 is fully rotated in the direction of arrow B so that the ground work equipment is in the lowered position, and the draft lever 12 is rotated in the same direction of arrow B to the position, the actuator 19 is The spool arm 21 is no longer in contact with the actuator 18, and only the actuator 18 is in contact with the spool arm 21.
This draft lever 1
The ground work machine will descend to the position indicated by 2 to perform the tilling work, and at this time, if the tillage resistance acting on the ground work machine becomes greater than the value set by the spring 28, the top link will be activated. Bracket 26, which is pushed to the left in FIG. 1 at 34, pushes draft rod 27 in the same direction, so that arrow A
The spool arm 21 pushed in the direction
in the same direction to raise the lift arm 9. In this way, the draft lever 1
Based on the premise that the hydraulic lifting actuator is configured to control the lifting and lowering of the ground working machine so as to maintain the tilling resistance within a certain range with the plowing depth specified by 2 as the lower limit, in this invention, A bracket 36 is provided at the opening edge of the side hydraulic cylinder 4, and a return arm 38 is attached to a shaft 37 that is rotatably fitted into the bracket 36.
A protrusion 39 is screwed onto the rotating tip of the spool arm so that its protruding position can be adjusted.A torque spring 40, which has both ends locked to the return arm 38 and the bracket 36, allows the protrusion 39 to always be attached to the spool arm. 21 to rotate in the direction of arrow A,
The rotating tip of the arm 41 attached to the shaft 37 is set within the movement trajectory of the hydraulic piston 6 near the outer periphery of the lift shaft 8, forming an interlocking mechanism 42, as shown in FIG. At an intermediate position in the lifting and lowering movement until the arm 9 reaches its maximum upward movement,
Since the hydraulic piston 6 does not protrude from the hydraulic cylinder 4, the arm 38 returns until the arm 41 comes into contact with the opening edge of the hydraulic cylinder 4, and the arm 38 rotates clockwise around the shaft 37. At this position, the interlocking mechanism 42 stands still;
At this time, the protrusion 39 separates from the spool arm 21 and the position link 17 or draft link 1 operates the spool arm 21.
The spool arm 21 controls the slider 3 according to the command from the hydraulic piston 6, but when the lift arm 9 further rises from the position shown in FIG. The arm 41 is pushed by the hydraulic piston 6 and rotates the return arm 38 of the interlocking mechanism 42 toward the spool arm 21, as shown in FIG. Since the spool arm 21 returns to the neutral position, the slider 3 protrudes in the direction opposite to the arrow A and stops supplying and discharging pressure fluid to the hydraulic cylinder 4.
The lift arm 9 is also stopped so that a minimum gap S is secured between the lift crank 7 and the inner wall 1a of the cylinder case 1 to prevent collision between them.

Therefore, if the position lever 13 is rotated in the direction of the arrow B in FIG.
If the slider 3 moves in the direction of the arrow A, the lift arm 9 rotates downward, and if the slider 3 moves in the direction of the arrow A, the lift arm 8 rotates upward. Become. Also, if the position lever 13 is fully rotated in the direction of arrow B, which is the lowering direction, and the draft lever 12 is rotated in the direction of arrow B, for example, the tilling resistance from the ground work machine can be reduced. When the draft rod 27 becomes larger, the draft rod 27 is pushed to the left, moving the slider 3 in the same direction, and lifting the lift arm 9.
is controlled to increase and maintain tillage resistance within a certain range.

Then, the lift crank 7 is connected to the cylinder case 1.
Since the arm 41 of the interlocking mechanism 42 remains in contact with the opening edge of the hydraulic cylinder case 4 until the spool arm 21 approaches the protrusion 39
In this way, the interlocking mechanism 42 does not come into contact with the interlocking mechanism 42 and is not restricted by the interlocking mechanism 42.

However, when the lift arm 9 rises to the vicinity of the upper movement limit, the hydraulic piston 6 pushes the arm 41 of the interlocking mechanism 42, so the return arm 38 rotates toward the spool arm 21, and the protrusion 39 Since the spool arm 21 is forcibly pushed back in the direction opposite to arrow A, the slider 3 also moves in the same direction, stopping the protrusion of the hydraulic piston 6 and also stopping the upward rotation of the lift arm 9. be.

Therefore, due to the operation of the interlocking mechanism 42, the fear that the lift crank 7 will collide with the cylinder case 1 is completely eliminated, and the position lever 13
The necessary minimum gap S can be secured between the cylinder case 1 and the lift crank 7 regardless of the operating position of the draft lever 12, and the adjustment work for this gap S can be done by the lift. It is sufficient to simply adjust the screwing position of the protrusion 39 while directly visually confirming the operation of the crank 7. This invention completely eliminates the inconvenience of having to adjust each position using a stopper. And interlocking mechanism 4
The arm 41 of the second arm 41 and the return arm 38 side contact the skirt portion near the outer circumference of the hydraulic piston 6 only when the lift arm 9 rotates to the upper limit position, and the return arm 38 side contacts the spool arm 20. When the lift arm 9 moves up and down below the upper limit position, the arm 41 does not come into contact with the skirt portion and the return arm 38 does not come into contact with the spool arm 20. The wear of the arm 41 and the return arm 38 is small, the gap S between the cylinder case 1 and the lift crank 7 is maintained over a long period of time without having to adjust the interlocking mechanism 42, and the hydraulic piston 6 The return arm 38 returns the spool arm 21 and the slider 3 to the direction in which the lift crank is stopped by the arm 41 that engages with the protrusion of the arm 41. The adjustment work of the mechanism 42 has become extremely simple, and unlike the conventional method in which a stopper is provided on the position lever or draft lever, the stopper installation by intervening a complicated link mechanism up to the slider 3 is now possible. This invention successfully solves the difficulty of position adjustment.

[Brief explanation of the drawing]

1 and 3 are longitudinal sectional side views of essential parts of a hydraulic lifting/lowering operating device to which the safety mechanism of this invention is applied, and FIG. 2 is a front sectional view thereof. Explanation of symbols, 1... Cylinder case, 1a...
Inner wall, 2... Hydraulic valve, 3... Slider, 4...
Hydraulic cylinder, 5, 22, 28, 33... spring,
6... Hydraulic piston, 7... Lift crank, 8
...Lift axis, 9...Lift arm, 10, 11
...Double shaft, 12...Draft lever, 13...
Position lever, 14, 15... Crank pin, 16... Draft link, 17... Position link, 18, 19... Operator, 20, 24,
25, 30, 31, 35...Pin, 21...Spool arm, 23...Cam, 26, 36...Bracket, 27...Draft rod, 29...Arm rod, 34...Top link, 37...Shaft , 38...
... Return arm, 39 ... Protrusion, 40 ... Torque spring, 41 ... Arm, 42 ... Interlocking mechanism, 43 ...
...Conrod, S...Gap.

Claims (1)

[Claims] 1 The hydraulic piston controls the supply and discharge of pressure fluid to and from the hydraulic piston by moving the slider of the hydraulic valve in and out, so that the hydraulic piston raises and lowers the lift crank of the lift shaft that suspends the ground work equipment. In the constructed hydraulic lifting/lowering operating device, an arm extending from the opening edge of the hydraulic cylinder into the movement locus of the hydraulic piston is attached to the shaft provided on the upper outer periphery of the hydraulic cylinder, and a spool located on the slider side. A return arm that can come into contact with the arm is provided, and an interlocking mechanism is provided in which the return arm side is separated from the spool arm when the arm comes into contact with the opening edge of the hydraulic cylinder due to a torque spring. , this interlocking mechanism is a hydraulic mechanism configured to move the slider in the direction in which the lift crank stops as the hydraulic piston moves in the upward rotation direction near the upper limit of the lift crank. Safety mechanism for pressure lift actuator.