JPH1033012A - Hydraulic pressure-operating apparatus of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conveniently carry out control operation of lifting and lowering limit in good workability. SOLUTION: A lifting and lowering operation lever 17 is disposed in the front of a lift arm 5, an operating tool 24 moving along a control rod 23 interlocking with the lifting operation lever 17, accompanied by oscillation of the lift arm 5 is fitted an a lifting and lowering limit tool A for moving a control rod 23 so as to return the lifting and lowering operation lever 17 to the neutral position N is installed so as to enable free position control operation in a part between the lifting and lowering operation lever 17 and the operating tool 24 in the control rod 23. A pressurized part A1 located in a part between the operating tool 24 and the lifting and lowering operation lever 17 in the control rod 23 and pressurized by contact with the operation tool 24, an attaching part A2 attached to the rear part than the operating tool 24 in the control rod 23 and a connecting part A3 for connecting the pressurized part A1 to a connecting part A2 are arranged to constitute the lifting and lowering limit tool A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can adjust the ascending and descending limits of a working device such as a tilling device, and automatically stop the ascending and descending when the working device is at an ascending or descending limit. More specifically, a lift arm for raising and lowering a working device that is vertically driven and oscillated via a hydraulic cylinder is provided at a rear portion of the vehicle body, and a lifting operation lever for operating a hydraulic control valve for the hydraulic cylinder is provided. Is provided in front of the lift arm, and a control rod in a front-rear position interlocked with the lifting operation lever, and an operating tool that moves along the control rod in accordance with the swing of the lift arm are provided. The portion positioned between the lifting operation lever and the operation tool is pressed against the operation tool by the swing of the lift arm, thereby The lifting limit device for moving the control rod to the neutral position for the hydraulic control valve to lift the neutral state to a hydraulic operating device for a work vehicle that is mounted for position adjustment operation in the longitudinal direction of the control rod.

[0002]

2. Description of the Related Art In a conventional hydraulic operating device for a working vehicle, FIG.
As shown in FIG. 5, the operation tool 2
The pressure-receiving portion A1 and a set bolt 60 for mounting the pressure-receiving portion A1 in the longitudinal direction of the control rod 23 so as to be freely adjustable are provided in a portion located between the control lever 4 and the lifting / lowering operation lever 17. The lift arm 5 is provided on a portion of the control rod 23 located rearward of the operation tool 24.
A second lifting / lowering limiter B for moving the control rod 23 so that the lifting / lowering operation lever 17 is returned to the neutral position N by being pressed against the operating tool 24 with the swing of
The lifting / lowering limiter A is replaced with a lowering limiter 26 or an ascending limiter 25.
On the other hand, the second lifting / lowering limiter B is used as the raising / lowering limiter 25 or the lowering / lowering limiter 26.

[0003] That is, when the lifting operation lever 17 is operated to the ascending position U to switch the hydraulic control valve 15 to the ascending state, when the lift arm 5 reaches the ascending limit, the ascending limit tool 25 is pressed by the operating tool 24. As a result, the control rod 23 is moved to return the elevating operation lever 17 to the neutral position N, whereby the hydraulic control valve 15 is set to the neutral state, and the upward swing of the lift arm 5 is automatically stopped. When the operating lever 17 is operated to the lowering position D, the hydraulic control valve 1
When the lifting arm 5 reaches the lowering limit when the switch 5 is switched to the lowering state, the lowering limit tool 26 is pressed by the operating tool 24 to move the control rod 23 to move the lifting / lowering operating lever 17 to the neutral position N. By returning, the hydraulic control valve 15 is set to the neutral state, and the lowering swing of the lift arm 5 is automatically stopped. Then, the control rods 23 of the lifting and lowering limiter A and the second lifting and lowering limiter B are used.
By adjusting the position of attachment to the device, the ascending limit and the descending limit were adjusted. In the drawing, the lowering limiter 26 is provided as the lifting / lowering limiter A, and the ascending limiter 25 is provided as the second lifting / lowering limiter B.

[0004]

However, in the case of the above-mentioned conventional technology, the entire lifting and lowering device is an operating device, that is,
Since it was placed in a narrow space between the lift arm and the lifting operation lever, there was a drawback that it was difficult to adjust the position of the lifting limit device by loosening and tightening the set bolts to adjust the lifting limit. .

[0005] Particularly, in the tillage work, the adjustment of the lowering limit is a frequent adjustment of the plowing depth. In such a case, it is very inconvenient if the lifting and lowering limit tool is the lowering limit tool.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to conveniently perform an operation of adjusting the ascending and descending limit by adjusting the position of an ascending and descending limit tool with good workability.

[0007]

The features, functions and effects of the first aspect of the present invention are as follows.

[Features] A lift arm for raising and lowering a working device, which is vertically driven and oscillated via a hydraulic cylinder, is provided at a rear portion of the vehicle body, and a lifting operation lever for operating a hydraulic control valve for the hydraulic cylinder is provided by the lift. A control rod, which is provided in front of the arm, and has a forward-backward posture interlocked with the elevating operation lever, and an operating tool which moves along the control rod in accordance with the swing of the lift arm; Lifting / lowering limit device that moves a control rod to return the lifting / lowering operation lever to a neutral position by being pressed against the operation device along with the swing of the lift arm at a portion located between the control device and the operation device. A hydraulic operating device for a working vehicle, wherein the position adjusting operation is freely mounted in the longitudinal direction of the control rod, In the configuration of the control rod, a pressure-receiving portion which is located at a portion between the operating tool and the elevating operation lever of the control rod and is pressed by the operating tool, and a portion of the control rod behind the operating tool. The point is that a mounting portion to be mounted and a connecting portion for connecting the pressure-receiving portion to the mounting portion are provided.

According to the first aspect of the present invention, the ascending / descending limit is determined by a pressure-receiving portion disposed between the operating tool and the lifting / lowering operating lever, a mounting portion disposed behind the operating tool, and a connecting portion connecting these components. Since the tool is configured to fix the position of the pressure-receiving portion by mounting the mounting portion to the control rod, the position of the pressure-receiving portion can be adjusted by changing the position of the mounting portion. And since the mounting part is attached to the part of the control rod behind the operating tool, it is a lifting / lowering limit tool that is arranged between the lifting / lowering operating lever and the operating tool. It is unnecessary to perform an adjustment operation at a narrow portion sandwiched therebetween, and the adjustment operation can be performed at a wide and easy-to-operate portion such as behind the operation tool.

[Effects] Therefore, according to the first aspect of the present invention, the adjustment of the ascent and descent limits by adjusting the mounting position of the ascending and descending limit tool to the control rod can be conveniently performed with good workability. Was.

The features, functions and effects of the second aspect of the present invention are as follows.

[Features] In the features of the first invention,
The control rod is moved back to the neutral position by being pressed against the operating tool along with the swing of the lift arm on a portion of the control rod behind the operating tool to return the elevating operation lever to the neutral position. Is mounted as an ascending limit tool, the ascending and descending limit tool is mounted as a descent limit tool, and a mounting portion of this descent limit tool is disposed behind the ascending limit tool.

[Operation] According to the second aspect of the invention, while the lower limit member is disposed between the lifting operation lever and the operating tool, the mounting portion of the lower limit member is disposed behind the operating tool. Since it is arranged behind the ascending limit device, the operation on the mounting portion of the ascending limit device can be performed without being disturbed by the ascending limit device.

[Effect] Therefore, according to the second aspect of the present invention, the lower limit tool must be disposed between the lifting operation lever and the operating tool when performing the tilling work in which the lower limit is frequently performed. , The lower limit adjustment can be performed with good workability.

The features, functions and effects of the third aspect of the present invention are as follows.

[Features] In the features of the first invention,
The control rod is moved to return the lifting operation lever to the neutral position by being pressed against the operation tool along with the swing of the lift arm in a portion of the control rod behind the operation tool. The lifting / lowering limit tool is mounted as a lower limit tool, the lifting / lowering limit tool is mounted as a rising limit tool, and the lowering tool is an operating tool which is located between an operating tool and a mounting portion of the control limit tool of the control rod. Provided are a pressure-receiving part to be pressed against, a mounting part that is mounted on the part of the control rod behind the mounting part of the ascending limit device, and a connecting part that connects the pressure-receiving part to the mounting part. There is a point.

[Operation] According to the third aspect of the present invention, the ascending limit device disposed between the elevating operation lever and the operating tool is constituted by the pressure-receiving portion, the mounting portion, and the connecting portion. Easy to operate. In addition, since the lowering limit device is also composed of a pressure-receiving portion, a mounting portion, and a connecting portion, and the mounting portion of the lowering limit device is disposed behind the mounting portion of the rising limit device, the lowering limit device which is frequently used The operation on the mounting portion of the tool can be easily performed.

[Effects] Therefore, according to the third aspect of the present invention, when performing the tilling work in which the lowering limit adjustment is frequently performed, the raising limit tool must be arranged between the lifting operation lever and the operating tool. Even in the case where there is the above restriction, the lower limit adjustment can be performed with good workability while improving the workability of the upward limit adjustment.

The features, functions and effects of the fourth aspect of the present invention are as follows.

[Features] In the features of the first invention, the second invention, and the third invention, the control rod is disposed below the swing axis of the lift arm.

[Operation] According to the fourth aspect of the present invention, the control rod does not protrude above the transmission case.

[Effect] Therefore, according to the fourth aspect of the present invention, the control rods can be arranged collectively.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a riding cultivator has a pair of left and right driving steering front wheels 1, a pair of left and right driving rear wheels 2, a driving seat 3, a steering handle 4,
A pair of left and right lift arms 5 that can freely move up and down at the rear of the vehicle body,
A top link 8a and a pair of left and right lower links 8b are provided at the rear of a tractor 7 which is an example of a working vehicle provided with a hydraulic cylinder (hereinafter, referred to as a lift cylinder) 6 for driving the lift arm 5 to swing up and down. The tillage device 9 is connected to the lift arm 5 via a three-point link mechanism 8 comprising a lower link 8 b and a lift rod 10.
And is configured to drive up and down the tillage device 9. E is an engine.

As shown in FIG. 3, the lift arm 5 is supported by a cylinder case 12 attached to an upper part of a transmission case 11 constituting a rear portion of the tractor 7 so as to be able to swing up and down.

The lift cylinder 6 is extended by supply of pressurized oil to swing the lift arm 5 upward, and is discharged by pressurized oil to shorten the lift arm 5 by the weight of the tilling device 9 to swing the lift arm 5 downward. The cylinder tube portion forming the cylinder chamber is a cylinder case 1
2 are integrally formed.

As shown in FIG. 2, the hydraulic circuit for the lift cylinder 6 includes a lift state in which hydraulic oil from a hydraulic pump 13 is supplied to the lift cylinder 6 so as to extend the lift cylinder 6; The pressure oil from the lift cylinder 6 is returned to the tank 14 so as to shorten the operation of the lift cylinder 6, and the pressurized oil is supplied to the lift cylinder 6 and the tank 14 is moved from the lift cylinder 6 to fix the expansion / contraction state of the lift cylinder 6. A hydraulic control valve 15 that can be switched between a lifting and lowering neutral state that prevents return of the hydraulic cylinder and an open / close valve that can be switched between an open state that allows supply and discharge of pressurized oil to and from a closed state that prevents supply and discharge of the lift cylinder 6. 16 and a relief valve R for safety.

The hydraulic control valve 15 is a spool valve that changes its state by moving a direct-acting spool 15A, and is disposed below the cylinder case 12 in such a manner that the moving direction of the spool 15A is in the front-rear direction. ing.

The hydraulic operating device for operating the hydraulic control valve 15 is, as shown in FIGS. 3 to 5, a manually operated lifting / lowering portion of the side wall 12a of the cylinder case 12 in front of the lift cylinder 6. An operation lever 17 is attached to be able to swing back and forth around a left-right axis P, and a support shaft 1 that swings integrally with the lift operation lever 17 is provided with the support shaft 1.
8, the operation arm 1 for moving the spool 15A of the hydraulic control valve 15 in accordance with the swing of the lifting operation lever 17
9 and attach the operation arm 1 to the side wall 12a.
The detent ball 22 for engaging the operation arm 19 in the neutral position by entering the concave portion 20 formed in the operation arm 19 by the elastic force of the spring 21 when the 9 is swung to the position that brings the spool 15A to the neutral position. It is provided and configured.

Incidentally, the interlocking relationship between the lifting operation lever 17 and the hydraulic control valve 15 is from the neutral position N to the rear rising position U from the neutral position N as shown in FIGS. The hydraulic control valve 15 is switched from the neutral state of elevation to the ascending state by the operation of the hydraulic control valve 15, and the hydraulic control valve 15 is changed from the neutral state of elevation to the descending state by the operation of the elevation operation lever 17 from the neutral position N to the descending position D in front. It is designed to switch.

The hydraulic operating device sets a swing range of the lift arm 5, that is, a lifting range of the tilling device 9, and when the tilling device 9 rises to the upper limit position of the lifting range, the hydraulic control valve When the tilling apparatus 9 is lowered to the lower limit position of the elevating range, the hydraulic control valve 15 is switched to the elevating neutral state to stop the descent while the tilling apparatus 9 is lowered to the lower limit position of the elevating range. Have.

As shown in FIGS. 3 to 6, the lifting / lowering limit automatic stop means moves forward by operating the lifting / lowering operating lever 17 to the ascending position U and moves backward by operating to the descending position D. Lifting operation lever 17 to move
Among them, a control rod 23 in a front-rear direction interlocking with a portion below a left-right axis P is disposed below a swing shaft 5A of the lift arm 5 and the lift arm 5 Is inserted through a hole 24a formed in an operating tool 24 attached to a bracket portion 5a protruding from a base end portion of the control rod 23 so as to be swingable around a first left-right axis P1. The lift between the tool 24 and the lifting operation lever 17 is brought into contact with and pressed by the operating tool 24 that moves forward along the control rod 23 as the lift arm 5 swings downward. The lowering limiter 26 as the lifting and lowering limiter A for moving the control rod 23 to return the operation lever 17 to the neutral position N is positioned at the neutral position N. Longitudinally mounted for position adjustment operation of the control rod 23 so as to adjust the swing position of the lift arm 5 to the control rod 23
The lifting / lowering operating lever is pressed against the operating tool 24 that moves rearward along the control rod 23 along with the upward swing of the lift arm 5 at a position behind the operating tool 24. The lifting limiter 25 as the second lifting and lowering limiter B for moving the control rod 23 so as to return the 17 to the neutral position N, and the swinging position of the lift arm 5 for positioning the lifting operation lever 17 at the neutral position N are adjusted. The control rod 23 is mounted so as to be freely position-adjustable in the longitudinal direction.

As shown in FIGS. 3 and 6, the operating tool 24 is swingably inserted into the bracket portion 5a by pressing half of one shaft member, and is retained by the retaining ring 29. And a plate-shaped operation portion 24B having a hole 24a.

As shown in FIG. 7, the ascending limiter 25, ie, the second ascending and descending limiter B, allows the control rod 23 to be movably inserted, and
The U-shaped pressure-receiving portion B1 contacted and pressed by the operating tool 24 in accordance with the swing of the pressure-raising to the ascending limit, and the pressure-receiving portion B1 is fixed to the control rod 23 by being tightened, and is loosened by being loosened. It is configured such that the position can be adjusted with respect to the control rod 23 from the set bolt 27 that allows the movement of the pressure portion B1.

As shown in FIG. 7, the lower limit member 26, that is, the raising and lowering limiter A, movably inserts a portion of the control rod 23 located between the operating tool 24 and the raising and lowering operation lever 17. At the same time, a plate-shaped pressure-receiving portion A1 contacted and pressed by the operating tool 24 as the lift arm 5 swings to the lower limit, and a control rod 23 A U-shaped mounting portion A2 which is mounted so as to be freely position-adjustable in the longitudinal direction, and a set bolt 28 which fixes the mounting portion A2 to the control rod 23 by tightening and allows the mounting portion A2 to move by loosening. And the pressure-receiving portion A1 is connected to the mounting portion A2 to control the pressure-receiving portion A1 via the mounting portion A2. Plate-shaped to be fixed to the 23 connecting section A3
Consists of The pressure receiving portion A1, the mounting operation portion A2, and the connecting portion A3 are integrally formed by bending a single plate.

Therefore, according to the lifting / lowering limit automatic stopping means, by adjusting the mounting position of the rising / lowering limit tool 25 and the lowering limit tool 26 to the control rod 23, the vertical swing range of the lift arm 5, that is, The raising and lowering range of the tilling device 9 is set. As shown in FIG. 4B, when the tilling device 9 is raised by operating the raising and lowering operation lever 17 to the raising position U, the tilling device 9 is moved upward and downward. Is raised to the ascending limit, the pressed portion B1 of the operating tool 24 contacts and presses the ascending limit tool 25 to move the control rod 23 to the neutral position side (rearward), thereby moving the elevating operation lever 17 to the neutral position. N, the hydraulic control valve 15 is switched from the rising state to the lifting neutral state, whereby the lifting is automatically stopped. On the other hand, as shown in FIG. When the tilling device 9 is lowered to the lower limit of the elevating range when the tilling device 9 is moved to the position D, the operating tool 24 abuts and presses the pressurized portion A1 of the lower limit adjusting device 26 to control the control rod 23. Is moved to the neutral position side (forward), the lifting operation lever 17 is swung to the neutral position N, and the hydraulic control valve 15 is switched from the lowering state to the raising and lowering neutral state, whereby the lowering is automatically stopped.

The on-off valve 16 is configured by using the cylinder case 12 as a valve case. Specifically, as shown in FIG. 8, an operation for rotating the adjustment rod 32 at the outer end of the adjustment rod 32 having a male screw portion 31 that can be screwed into the female screw portion 30 formed in the cylinder case 12. While the knob 33 is mounted, the oil passage 35 is closed at the inner end by contacting the valve seat 34 formed in the cylinder case 12 with the tightening of the male screw portion 31 into the female screw portion 30, and the valve is loosened. Valve body 3 that is separated from seat 34 to open oil passage 35
6 and an O-ring 37 for preventing oil leakage from the threaded portion of the female screw portion 30 and the male screw portion 31 when opened. That is, by tightening the adjustment rod 32, the oil passage 35 is closed and the lift cylinder 6 is locked in its expanded / contracted state, and by loosening the adjustment rod 32, the oil passage 35 is opened to lift the lift cylinder 6 It is designed to be able to expand and contract. 38 is the adjusting rod 32
This is a retaining ring that engages with the stopper 39 that is engaged and held by the retaining ring to prevent the adjustment rod 32 from coming off.

In the transmission case 11, as shown in FIG. 9, a traveling for transmitting the power from the motor shaft 41 of the hydrostatic continuously variable transmission 40 driven by the power from the engine E to the traveling system. And a power take-out transmission 46 that transmits power from the pump shaft 43 of the hydrostatic continuously variable transmission 40 to a rear power take-out shaft 44 and a front power take-out shaft 45. Is provided.

The power take-out system transmission section 46 is provided with a first intermediate gear 47 for shifting that is interlocked with the pump shaft 43 via a pair of gears G1 and G2, and a first gear section 47A of the first intermediate gear 47. A transmission gear 48, which can be selectively interlocked with the second gear portion 47B and operable to release the interlock, is interlocked with the rear power take-out shaft 44, and the transmission gear 48 of the pair of gear portions 48A, 48B for speed increasing transmission. In a state where the gear portion 48A of the first intermediate gear 47 meshes with and is interlocked with the first gear portion 47A of the first intermediate gear 47, the second intermediate gear 50 that meshes with and interlocks with the gear portion 48A is rotatably held by the support shaft 51, and The gear 52, which is interlocked with the third intermediate gear 50, is interlocked with the power take-out shaft 45, which is forward. In other words, the gear portion 48A for speed-up transmission of the transmission gear 48 is meshed with the first intermediate gear 47A to be interlocked with the first intermediate gear 47A.
Power is transmitted to the rear power take-out shaft 44 and the front power take-out shaft 45, and the other gear portion 48B is engaged with and interlocked with the second intermediate gear 47B, thereby transmitting the power to the front power take-out shaft 45. The power is transmitted only to the rear power take-out shaft 44 in the cut-off state.

As shown in FIGS. 10 to 12, means for supporting the support shaft 51 on the transmission case 11 in a non-rotating state is such that a recess 53 is formed in the transmission case 11, and the support shaft 51 is engaged with the recess 53. This is a means for forming a projection 54 for preventing the rotation of the support shaft 51 by press molding.

[Another Embodiment] The ascent / descent limit automatic stop means in the above embodiment is modified as follows.

As shown in FIG. 13, the raising / lowering operation lever 17 moves to the rear by the operation of the raising / lowering operation lever 17 to the ascending position U, and moves forward by the operation to the lowering position D. A control rod 2 in a front-rear position that is interlocked with a position above the left-right axis P.
3 is disposed above the swing shaft 5A of the lift arm 5, and a second left-right axis P2 is attached to a bracket 5b protruding from the lift arm 5.
The operation arm 24 is swingably mounted around the control rod 23 so as to be movable back and forth, and the control rod 23 is swung upward by the lift arm 5 at a position between the operation tool 24 and the elevating operation lever 17. With the control rod 23
A lifting limit tool 25 serving as a lifting limit tool A for moving the control rod 23 so as to return to the neutral position N by raising and lowering the operation lever 17 by being pressed against the operating tool 24 moving forward along The control valve 23 is attached to the control rod 23 so as to adjust the swinging position of the lift arm 5 for raising and lowering the control valve 15 to the neutral position in the longitudinal direction of the control rod 23. The control rod moves the lifting / lowering operation lever 17 back to the neutral position N by being pressed against the operating tool 24 moving backward along the control rod 23 with the downward swing of the lift arm 5. The lower limiter 26 serving as a second raising / lowering limiter B for moving the lift 23 is moved up and down by the lift arm 5 Position in the longitudinal direction of the control rod 23 so as to adjust the swing position adjustment operably attached is constructed.

The lowering limiter 26, ie, the second raising and lowering limiter B, allows the control rod 23 to be movably inserted therein, and abuts and presses by the operating tool 24 as the lift arm 5 swings to the lowering limit. The pressure-receiving portion B1 is fixed to the control rod 23 by tightening and the pressure-receiving portion B1 is loosened.
The position can be adjusted with respect to the control rod 23 from a set bolt 27 that allows the movement of the control rod 23.

The ascending limiter 25, that is, the ascending and descending limiter A, allows the portion of the control rod 23 located between the operating tool 24 and the elevating operation lever 17 to be movably inserted thereinto, The plate-shaped pressure-receiving portion A1 pressed and pressed by the operation tool 24 in accordance with the swing to the limit
And the lower limit member 26 of the control rod 23
U-shaped mounting part A that is mounted on the rear part of the control rod so that the position can be adjusted in the longitudinal direction of the control rod.
2, the mounting portion A2 is fixed to the control rod 23 by tightening, and the pressure-receiving portion A1 and the mounting portion A2 are connected to the set bolt 28 that allows the mounting portion A2 to move by loosening. A plate-shaped connecting portion A3 for fixing the pressure-receiving portion A1 to the control rod 23 via the mounting portion A2. In addition,
The pressure-receiving portion A1, the mounting operation portion A2, and the connecting portion A3 are integrally formed by bending a single plate.

Therefore, according to the lifting / lowering limit automatic stop means, by adjusting the mounting position of the lifting / lowering limit tool 25 and the lowering / lowering limit tool 26 to the control rod 23, the vertical swing range of the lift arm 5, that is, The raising and lowering range of the tilling device 9 is set. When the tilling device 9 is raised to the upper limit of the raising and lowering range by raising the tilling device 9 by operating the raising and lowering operation lever 17 to the raising position U, the operating tool 24 is set. Moves the control rod 23 toward the neutral position (rearward) by pressing and pressing the pressure-receiving portion A1 of the ascending limit device 25, thereby swinging the elevating operation lever 17 to the neutral position N, When the tilling device 9 is lowered by operating the raising / lowering operation lever 17 to the lowering position D, the cultivation is performed by switching the tilling device from the rising state to the neutral state. When 9 moves down to the lower limit of the raising / lowering range, the operating tool 24 abuts and presses the pressurized portion B1 of the lowering limit tool 16 to move the control rod 23 to the neutral position side (front), whereby the raising / lowering operating lever is moved. The lowering is automatically stopped by swinging the hydraulic control valve 15 from the lowered state to the neutral state in which the hydraulic control valve 15 is raised and lowered by swinging the hydraulic pressure control valve 17 to the neutral position N.

In the other embodiment, as shown in FIG. 14, the lowering limiter 26 as the second lifting and lowering limiter B is
A portion of the control rod 23 located behind the operating tool 24 is movably inserted, and a plate-shaped pressure-receiving portion pressed and contacted by the operating tool 24 as the lift arm 5 swings to the lower limit. B1, a U-shaped mounting portion B2 which is mounted on a portion of the control rod 23 behind the mounting portion A2 of the ascending limit tool 25 so as to be capable of adjusting the position in the longitudinal direction of the control rod, and
The mounting portion B2 is fixed to the control rod 23 by tightening, and the mounting portion B2 is fixed by loosening.
2 and the pressure-receiving portion B
1 and a plate-shaped connecting portion A3 for connecting the mounting portion B2 to fix the pressure-receiving portion A1 to the control rod 23 via the mounting portion B2. The pressure receiving portion B1, the mounting operation portion B2, and the connecting portion B3 are integrally formed by bending a single plate.

[Brief description of the drawings]

Fig. 1 Side view of a cultivator

FIG. 2 is a hydraulic circuit diagram for a hydraulic cylinder for driving a lift arm.

FIG. 3 is a side view of an ascent / descent limit automatic stop mechanism.

FIG. 4 is an explanatory diagram of an operation of an ascent / descent limit automatic stop mechanism.

FIG. 5 is a cross-sectional view of a lifting operation lever mounting portion.

FIG. 6 is a sectional view of a main part of the lift arm.

FIG. 7 is a perspective view of a main part of an ascent / descent limit automatic stop mechanism.

FIG. 8 is a longitudinal sectional view of an on-off valve.

FIG. 9: Transmission system diagram

FIG. 10 is a longitudinal sectional view of a main part in a transmission case.

FIG. 11 is a cutaway plan view of a detent structure of a spindle.

FIG. 12 is a cross-sectional view of a rotation preventing structure of a spindle.

FIG. 13 is a side view of an ascent / descent limit automatic stop mechanism according to another embodiment.

FIG. 14 is a perspective view of a main part of an ascent / descent limit automatic stop mechanism showing another embodiment.

FIG. 15 is a side view of an ascent / descent limit automatic stop mechanism showing a conventional technique.

[Explanation of symbols]

 Reference Signs List 5 Lift arm 5A Swing shaft 6 Hydraulic cylinder 15 Hydraulic control valve 17 Lifting control lever 23 Control rod 24 Operating tool 25 Lifting limit tool 26 Lowering limit tool N Neutral position A Lifting / lowering limiter A1 Pressure-receiving part A2 Mounting part A3 Connecting part B Second lifting / lowering limiter B1 Pressure-receiving part B2 Mounting part B3 Connecting part

Claims (4)

[Claims] 1. A lift arm for raising and lowering a working device, which is vertically driven and oscillated via a hydraulic cylinder, is provided at a rear portion of a vehicle body, and a lift operating lever for operating a hydraulic control valve for the hydraulic cylinder is provided with the lift arm. In front of the
A control rod having a forward / backward posture interlocked with the lifting / lowering operation lever, and an operating tool that moves along the control rod in accordance with the swing of the lift arm are provided, and the lifting / lowering operating lever and the operating tool among the control rods are provided. A lifting / lowering limit device that moves a control rod so that the lifting / lowering operation lever is returned to a neutral position by being pressed against an operating tool in association with the swing of the lift arm, at a portion located therebetween, A hydraulic operating device for a working vehicle mounted so as to be capable of position adjustment operation in a direction, wherein the operating tool is located at a portion between the operating tool and an elevating operating lever in the control rod. A pressure-receiving portion contacted and pressed by the control rod, a mounting portion mounted on a portion of the control rod behind the operating tool, Work vehicle hydraulic operating device is provided with a connecting portion for connecting to the mounting portion. 2. A control rod for returning a lifting operation lever to a neutral position by being pressed against an operation tool with a swing of the lift arm on a portion of the control rod behind the operation tool. 2. A second ascent / descent limit device for moving the ascending limit device is attached as an ascending limit device, and the ascent / descent limit device is attached as a descent limit device, and a mounting portion of the ascending / lowering limit device is arranged behind the ascending limit device. Operating device of working vehicle. 3. The control rod is returned to a neutral position by being pressed against an operating tool of the control rod behind the operating tool by swinging the lift arm. A second lifting / lowering limit tool to be moved is attached as a lowering limit tool, the lifting / lowering limit tool is mounted as a rising limit tool,
A pressure-receiving portion of the control rod, which is located between the operating tool and the mounting portion of the ascending limit device and is pressed against the operating tool, and a portion of the control rod behind the mounting portion of the ascending limit device. 2. The hydraulic operating device for a work vehicle according to claim 1, further comprising a mounting portion to be mounted and a connecting portion connecting the pressure-receiving portion to the mounting portion. 4. The control rod according to claim 1, wherein the control rod is disposed below a swing axis of the lift arm.
Or the hydraulic operating device of the working vehicle according to 3.