JP5369004B2 - Tractor lever operating structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for operating a lever, which allows a lever to easily move between a lift arm operation range and an oil pressure supply range without possibility of labor for re-attachment of a restriction member and loss thereof, and realizes good operation performance. <P>SOLUTION: A restriction member 24 can manually switch from a lock state where movement of a hydraulic position lever 20 from a lift arm operation range to an oil pressure supply range is restricted to an unlock state where the movement of a hydraulic position lever 20 from the lift arm operation range to the oil pressure supply range is not restricted. After the restriction member 24 is manually brought into the unlock state and the hydraulic position lever 20 is moved to the oil pressure supply range, the hydraulic position lever 20 is moved to the lift arm operation range. By so doing, the restriction member 24 allows the operation to the lift arm operation rage to be automatically switched to the lock state. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a hydraulic position lever movable between a lift arm operating range for operating a lift arm of a tractor and a hydraulic pressure supply range for supplying hydraulic pressure of a hydraulic cylinder to the outside, and the hydraulic pressure supply range from the lift arm operating range. It is related with the lever operation structure of a tractor provided with the control member which controls the movement of the said hydraulic position lever to the side.

  As a conventional lever operation structure of this type of tractor, a lever guide for guiding a hydraulic position lever is provided, and the vicinity of the boundary between the lift arm operation range and the hydraulic supply range in the guide hole of the lever guide (the upper limit of the lift arm operation range) It is known that a regulating member that abuts and regulates the movement of the hydraulic position lever is fixed at a position via a bolt.

  In the lever operating structure described above, the lift arm can be lifted and lowered by moving the hydraulic position lever up and down within the lift arm operating range along the guide hole of the lever guide. And the hydraulic position lever is moved from the lift arm operation range to the hydraulic pressure supply range, so that the hydraulic pressure of the hydraulic cylinder can be taken out (see Patent Document 1).

  In another type of tractor lever operating structure, a spring member is provided near the boundary between the lift arm operating range and the hydraulic pressure supply range, and when the hydraulic position lever is moved to the hydraulic pressure supply range, the spring member is released when the hand is released. It is known that the hydraulic position lever is automatically returned to the lift arm operating range by the elastic restoring force of

JP 2006-129776 A

In the conventional structure of Patent Document 1, since it is necessary to remove the regulating member, there is a risk that the regulating member may be forgotten to be remounted after the hydraulic pressure is taken out, or the regulating member may be lost. If there is no restriction by the restriction member, the lever will unnecessarily move to the hydraulic pressure supply range, leading to power loss, an increase in oil temperature, failure of hydraulic parts, and the like.
Further, in the other conventional structure, in order to operate the hydraulic position lever to the hydraulic pressure supply range, the hydraulic position lever must be operated to the hydraulic pressure supply range against the elastic restoring force of the spring member. In the range, the operation of the hydraulic position lever becomes extremely heavy and the operation performance is deteriorated.

  An object of the present invention is that there is no risk of remounting or losing the regulating member, and the hydraulic position lever can be easily moved between the lift arm operating range and the hydraulic pressure supplying range, and the operating performance is good. It is to provide a lever operating structure.

  According to a first aspect of the present invention, there is provided a hydraulic position lever movable between a lift arm operating range for operating a lift arm of a tractor and a hydraulic pressure supply range for supplying hydraulic pressure of a hydraulic cylinder to the outside, and the lift arm operating A tractor lever operating structure including a restricting member that restricts movement of the hydraulic position lever from a range to the hydraulic pressure supply range, wherein the restricting member is configured to move the hydraulic pressure from the lift arm operating range to the hydraulic pressure supply range. It is possible to manually switch from a locked state that restricts movement of the position lever to an unlocked state that does not restrict movement of the hydraulic position lever from the lift arm operation range to the hydraulic pressure supply range, and After the hydraulic position lever is moved to the hydraulic pressure supply range in an unlocked state, Moving the position lever to the lift arm operation range, in that the regulating member are configured to switch automatically to the locked state allowing the operation to the lift arm operation range.

[Action and effect]
According to this configuration, in order to take out the hydraulic pressure, the control member is manually switched to the unlocked state, and then the hydraulic position lever is moved from the lift arm operating range to the hydraulic pressure supply range. There is no need to remove the members one by one, and there is no possibility of detaching the regulating member and losing the regulating member.
In addition, when the hydraulic pressure lever is moved to the lift arm operation range again after the hydraulic pressure of the hydraulic cylinder is removed, the regulating member automatically switches to the locked state, so that the forgetting to return the regulating member to the locked state does not occur. .
Further, in this configuration, it is not necessary to provide a biasing means such as a spring member for the hydraulic position lever. Therefore, the hydraulic position lever can be easily moved between the lift arm operation range and the hydraulic pressure supply range, and the operation performance is good.

  A second characteristic configuration according to the present invention includes a spring member that urges the regulating member from an unlocked state to a locked state, and the unlocking position when the hydraulic position lever is located in the hydraulic pressure supply range. The state regulating member is configured to contact the lateral side surface of the hydraulic position lever from a direction orthogonal to the moving direction of the hydraulic position lever, and to be pressed against the lateral side surface of the hydraulic position lever by the spring member. There is a point.

[Action and effect]
According to this configuration, since the hydraulic position lever is reliably held in the hydraulic pressure supply range by the pressing force of the restricting member in the hydraulic pressure supply range, the operation of taking out the hydraulic pressure of the hydraulic cylinder can be more stably performed.
When the hydraulic position lever is moved from the hydraulic pressure supply range to the lift arm operation range, the restricting member is in a state of sliding on the lateral side surface of the hydraulic position lever, and the movement of the hydraulic position lever is allowed. In this case, sliding resistance is applied to the hydraulic position lever from the regulating member, but the resistance is not too great.

  According to a third characteristic configuration of the present invention, the hydraulic position lever does not regulate movement of the hydraulic position lever to the hydraulic pressure supply range and resists the spring member separately from the locked state and the unlocked state. An intermediate state in which the restricting member is held at a position where it does not contact the lateral surface of the control unit is set, and the hydraulic position lever is moved from the lift arm operating range to the hydraulic pressure supply range with the restricting member set to the intermediate state. When it does, it exists in the point comprised so that the said control member may be in the unlocked state from the said intermediate state.

[Action and effect]
According to this configuration, by providing the intermediate state, the operator can operate the hydraulic position lever to the hydraulic pressure supply range after setting the regulating member to the intermediate state when performing the operation of taking out the hydraulic pressure of the hydraulic cylinder. Therefore, it is not necessary to operate the regulating member and the hydraulic position lever at the same time, and the operability is better.

Overall side view of tractor Side view of dump trailer connected to tractor Top view of the connecting part of the tractor and dump trailer Hydraulic circuit diagram for position control (A) Side view (b) Longitudinal front view (c) Plan view of lever operating structure when regulating member is in locked state (A) Side view (b) Vertical front view (c) Plan view of lever operating structure when the regulating member is in the intermediate state (A) Side view (b) Vertical front view (c) Plan view of lever operating structure when the regulating member is in the unlocked state (A) Side view (b) Longitudinal front view (c) Plan view of lever operating structure when regulating member is in locked state Perspective view of lever operating structure Plan view of lever operating structure according to another embodiment

Embodiments of the present invention will be described below with reference to FIGS.
[Overall structure of tractor]
A tractor having a lever operation structure according to the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 3, this tractor includes a front wheel 1 that is steered and a rear wheel 2 that is a propulsion wheel, and an engine 3 is mounted on the front of the body, and a rotary or the like is mounted on the rear of the body. And a pair of left and right lift arms 5 that drive up and down the three-point link mechanism 4 for connecting the working devices, and a driver seat 6 disposed between the left and right rear wheels 2 It has become.

  FIG. 4 shows a hydraulic circuit that hydraulically drives the lift arm 5. The lift arm 5 is driven by a single-acting hydraulic cylinder 7. The hydraulic cylinder 7 is extended by a hydraulic oil supply from a pump 31 driven by the engine 3 so that the lift arm 5 is driven upward, and the hydraulic cylinder 7 is shortened by being drained from the hydraulic cylinder 7 to thereby lift the lift arm 5. Is configured to descend by its own weight. The hydraulic cylinder 7 is controlled by a position control valve 8.

  The position control valve 8 includes a main spool 11, a lowering valve 12, a relief valve 13, a check valve 36, a pilot-operated check valve 34, etc., and a hydraulic cylinder 7 and a cylinder port 14 of the position control valve 8. Are connected via a drop speed adjusting valve 15. A relief valve 35 is connected between the hydraulic cylinder 7 and the drop speed adjustment valve 15, and the dump cylinder 10 that moves up and down the loading platform 29 of the dump trailer 23 includes the hydraulic cylinder 7 and the drop speed adjustment valve 15. Removably connected to a hydraulic pressure take-out portion 16 provided therebetween.

  A balance link 17 is swingably connected to the end of the main spool 11, and an adjustment arm 18 a extending from a position adjustment shaft 18 and a feedback arm extending from a feedback shaft 19 are connected to both ends of the balance link 17. 19a is respectively engaged. A position adjusting shaft 18 and a hydraulic position lever 20 disposed on the right side of the driver's seat 6 so as to be able to swing back and forth are mechanically linked via a linkage link 32, and the feedback shaft 19 and the lift arm 5 Are mechanically linked via a feedback link 33.

The position control valve 8 configured as described above operates as follows in a state where the dump cylinder 10 is not connected.
The state shown in FIG. 4 is a neutral state in which the hydraulic position lever 20 is held at an operation position with the lift arm operation range A, the main spool 11 is operated to the neutral position 11N, and the lowering valve 12 is operated to the closed position. Thus, the pilot pressure toward the closing side of the check valve 34 has disappeared. In this state, the pressure oil in the pump 31 is discharged through the check valve 34, and the pressure oil in the hydraulic cylinder 7 is stopped by the closed positions of the check valve 36 and the lowering valve 12.

  For example, when the hydraulic position lever 20 is operated to the ascending (U) side from the neutral state shown in FIG. 4, the position adjusting shaft 18 is rotated counterclockwise in FIG. Then, it swings in the downward direction on the paper surface with the engagement point with the feedback arm 19a as the center. Thus, with the lowering valve 12 held in the closed position, the main spool 11 is operated to the raised position 11U, and the check valve 34 is held in the closed state by the pilot pressure of the pilot oil path 37, and the pilot oil path The relief valve 13 is held closed by the pilot pressure of 38, pressure oil is sent from the cylinder port 14 to the hydraulic cylinder 7, and the lift arm 5 is driven to rise.

  When the lift arm 5 is displaced upward, this displacement is fed back to the feedback shaft 19 via the feedback link 33 as a counterclockwise rotation in FIG. 4, and the balance link 17 is centered on the engagement point with the adjustment arm 18a. Thus, the main spool 11 is moved to the neutral position 11N side. Then, when the feedback shaft 19 is rotated to a predetermined rotation position corresponding to the rotation operation position of the position adjusting shaft 18, the main spool 11 is returned to the neutral position 11N and the ascending operation is stopped.

  Further, when the hydraulic position lever 20 is operated to the lowering (D) side from the neutral state shown in FIG. 4, the position adjusting shaft 18 is rotated in the clockwise direction in FIG. The main spool 11 is swung upwardly with respect to the engagement point with the feedback arm 19a and the main spool 11 is moved to the lowered position 11D, and the lowering valve 12 that contacts and follows this is switched to the open position, and the cylinder By connecting the port 14 to the tank via the lowering valve 12, oil can be discharged from the hydraulic cylinder 7, and the lift arm 5 is lowered by its own weight.

  When the lift arm 5 is displaced downward, this displacement is fed back to the feedback shaft 19 via the feedback link 33 as a clockwise rotation in FIG. 4, and the balance link 17 is centered on the engagement point with the adjustment arm 18a. As a result, the main spool 11 is moved to the neutral position 11N side. When the feedback shaft 19 is rotated to a predetermined rotation position corresponding to the rotation operation position of the position adjustment shaft 18, the main spool 11 is returned to the neutral position 11N, and the lowering valve 12 is operated to the closed position. The descent operation is stopped.

  That is, when the hydraulic position lever 20 is operated within the lift arm operation range A of the lever guide 21, the lift arm 5 is moved up and down to a height corresponding to the operation position and automatically stopped. The lift arm 5 when the hydraulic position lever 20 is operated to the upper limit position is set to a position slightly lower than the mechanical lift limit of the lift arm 5 itself, and the hydraulic position lever 20 is operated to the lowermost position. In this state, the position control valve 8 is maintained in the lowered state without being returned to neutral regardless of the feedback operation accompanying the downward displacement of the lift arm 5, and the lift arm 5 is lowered to its mechanical lower limit. It is set so as to provide a possible state, a so-called floating state.

  Further, the hydraulic position lever 20 is moved to the hydraulic pressure supply range B of the lever guide 21 so that the hydraulic pressure of the hydraulic cylinder 7 can be taken out and supplied to an external device such as the dump trailer 23.

(Lever operation structure)
As shown in FIG. 9, the lever operation structure includes a hydraulic position lever 20, a lever guide 21, and a regulating member 24.

  As shown in FIG. 5 to FIG. 8, the front and rear guide holes 22 formed in the lever guide 21 on the right side of the driver seat 6 have a lift arm operation range A for operating the lift arm 5 of the tractor and the hydraulic cylinder 7. A hydraulic pressure supply range B for supplying hydraulic pressure to the outside is provided.

  The hydraulic position lever 20 is provided to penetrate through the guide hole 22, and a rocking support point 25 is provided with a friction holding mechanism 25 using a disc spring, and the hydraulic position lever 20 is provided between the lift arm operation range A and the hydraulic pressure supply range B. It is movable and can be held at a desired position within these ranges.

  As shown in FIG. 9, the restricting member 24 is formed by combining two round bars having different lengths bent in an L shape and welding them together in an F shape, and has a short shaft portion 24a and a long shaft portion. A portion 24b and a grip portion 24c are provided.

  The short shaft portion 24a of the restricting member 24 penetrates the two side walls 26a and 26a of the bracket 26 having a U-shaped cross section welded and fixed to the lower surface of the upper portion of the lever guide 21 in the lateral direction. The member 24 is pivotally connected to the bracket 26 so as to be able to rotate back and forth around the axis X of the short shaft portion 24a. A spring member 27 is provided on the outer periphery of the short shaft portion 24 a of the regulating member 24 so as to be disposed inside the bracket 26. The spring member 27 biases the restricting member 24 from the unlocked state to the locked state. In this embodiment, the elastic member 26 causes the restricting member 24 to move rightward of the vehicle body (FIG. 5B). Energize to move from right to left on the page.

  On the upper left side of the lever guide 21, there is provided an L-shaped cutout 28 comprising a deep portion 28a, a shallow portion 28b, and an arcuate guide portion 28c.

  In the state where the dump cylinder 10 is not connected, when the lift arm 5 is moved up and down, the restricting member 24 is locked to restrict the movement of the hydraulic position lever 20 from the lift arm operation range A to the hydraulic pressure supply range B. To do.

  As shown in FIGS. 5A to 5C, when the regulating member 24 is in the locked state, the short shaft portion 24a is located near the boundary C between the lift arm operation range A and the hydraulic pressure supply range B (lift arm operation). In the vicinity of the upper limit position of the range A), the hydraulic position lever 20 protrudes into the swing locus so as to be orthogonal to the guide hole 22 of the lever guide 21 in plan view. Then, as shown in FIG. 5C, the long shaft portion 24b of the restricting member 24 has a short shaft portion 24a in plan view, as shown in FIG. 5C by arranging the grip portion 24c of the restricting member 24 in the deep portion 28a of the notch 28. It is arranged on the rear side.

  As a result, the hydraulic position lever 20 hits the short shaft portion 24a of the regulating member 24 near the boundary C and its movement is restricted, so that the hydraulic position lever 20 cannot be moved above the boundary C. It is possible to move only within the range from the upper limit to the lower limit of the lift arm operation range A.

  When the hydraulic pressure of the hydraulic cylinder 7 is taken out and supplied to an external device such as the dump trailer 23, first, as shown in FIG. 6, the operator manually moves the grip 24c of the regulating member 24 to the spring member 27. After pulling to the left and right center side of the vehicle body against the elastic restoring force (the right side of the drawing in FIG. 6B), it is tilted backward around the axis X of the short shaft portion 24a of the regulating member 24 to The restricting member 24 is set in an intermediate state by being disposed in the shallow portion 28b.

  The regulating member 24 in the intermediate state is held at a position where it does not regulate the movement of the hydraulic position lever 20 to the hydraulic pressure supply range B and does not contact the lateral side surface of the hydraulic position lever 20 against the spring member 27. That is, as shown in FIGS. 6B and 6C, the short shaft portion 24a of the restricting member 24 deviates from the swinging locus of the hydraulic position lever 20, and the long shaft portion 24b of the restricting member 24 is short in plan view. It is disposed slightly in front of the shaft portion 24a and protrudes into the swing locus of the hydraulic position lever 20.

  Next, as shown in FIG. 7, when the hydraulic position lever 20 is moved to the hydraulic pressure supply range B, the long shaft portion 24b of the regulating member 24 is pushed backward by the hydraulic position lever 20, so that the regulating member 24 is shortened. The grip portion 24c is disengaged from the shallow portion 28b of the notch 28 by turning forward around the axis X of the shaft portion 24a, and the short shaft portion 24a of the regulating member 24 is moved to the right side of the vehicle body by the elastic restoring force of the spring member 27. An attempt is made to move in the direction (from the right to the left in FIG. 7B).

  Therefore, the short shaft portion 24a of the restricting member 24 extends from the direction orthogonal to the moving direction of the hydraulic position lever 20, that is, from the direction orthogonal to the guide hole 22 of the lever guide 21 in plan view to the left lateral surface of the hydraulic position lever 20. The spring member 27 is pressed against the left lateral surface of the hydraulic position lever 20 by contact.

  As a result, the regulating member 24 enters an unlocked state in which the movement of the hydraulic position lever 20 from the lift arm operation range A to the hydraulic pressure supply range B is not regulated, and the hydraulic pressure of the hydraulic cylinder 7 can be taken out. In the hydraulic pressure supply range B, the feedback link 33 does not act and the hydraulic pressure continues to be supplied. As a result, the dump cylinder 10 is extended and the loading platform 29 of the dump trailer 23 is raised.

  When the hydraulic position lever 20 is operated from the lift arm operation range A to the hydraulic pressure supply range B, the lift arm 5 to which the work device is not connected is lifted as described above within the range of the lift arm operation range A, and the upper limit is set. Although the dump cylinder 10 supports the load of the loading platform 29 in contrast to the position, the dump cylinder 10 does not actually operate (the loading platform 29 is not driven up).

  Then, when lowering or stopping the loading platform 29 of the dump trailer 23, as shown in FIG. 8, if the hydraulic position lever 20 is moved to the lift arm operation range A, the shortage of the regulating member 24 with respect to the left lateral surface of the hydraulic position lever 20 is shortened. The contact of the shaft portion 24a is released.

  When the hydraulic position lever 20 is operated from the hydraulic pressure supply range B to the lift arm operation range A, if the pressure of the hydraulic pressure takeout part 16 is relatively high, the lift arm 5 to which the work device is not connected is positioned at the upper limit position. Therefore, the main spool 11 is not operated to the neutral position 11N, and the dump cylinder 10 continues to contract (the loading platform 29 continues to descend). When the drop speed adjusting valve 15 is operated so that the hydraulic cylinder 7 contracts as the dump cylinder 10 contracts, the feedback link 33 functions in the lift arm operating range A, and the hydraulic position lever 20 The dump cylinder 10 stops at a position corresponding to the operation position (the loading platform 29 stops).

  When the hydraulic position lever 20 is moved from the hydraulic pressure supply range B to the lift arm operating range A, the short shaft portion 24a of the restricting member 24 is in a state of sliding on the lateral side surface of the hydraulic position lever 20, and the hydraulic position. The movement of the lever 20 is allowed. In this case, sliding resistance is applied to the hydraulic position lever 20 from the short shaft portion 24a of the regulating member 24, but the resistance is not too great.

  The short shaft portion 24a of the regulating member 24 is automatically in the vicinity of the boundary C between the lift arm operation range A and the hydraulic pressure supply range B (near the upper limit position of the lift arm operation range A) by the biasing force of the spring member 27. In the plan view, it protrudes into the swinging locus of the hydraulic position lever 20 so as to be orthogonal to the guide hole 22 of the lever guide 21, and the grip portion 24 c of the regulating member 24 is an arc-shaped guide of the notch 28. It enters the deep portion 28a via the portion 28c and automatically returns (switches) to the locked state. Thereby, forgetting to return the regulating member 24 to the locked state can be prevented.

[Another embodiment]
[1] As shown in FIG. 10, the regulating member 24 in the above-described embodiment may be urged by a spring member 27 using a rod-like body having a tapered surface 24d at the tip. That is, in this configuration, as shown in FIG. 10A, when the hydraulic position lever 20 is in the lift arm operation range A, the restricting member 24 protrudes into the swing locus of the hydraulic position lever 20 and is locked. .
Then, as shown in FIG. 10B, the operator manually moves the hydraulic position lever 20 to the hydraulic pressure supply range B while pulling the regulating member 24 away from the swinging locus of the hydraulic position lever 20. Thereafter, as shown in FIG. 10C, when the hydraulic position lever 20 is moved again to the lift arm operation range A, the hydraulic position lever 20 comes into contact with the tapered surface 24 d of the regulating member 24.
As a result, the regulating member 24 is pushed up in a direction away from the swing locus of the hydraulic position lever 20, and the hydraulic position lever 20 is allowed to move to the lift arm operation range A. When moved to A, the restricting member 24 is automatically switched to the locked state as shown in FIG. 10A again by the elastic restoring force of the spring member 27.

  The present invention is useful for a tractor that switches between operation of a lift arm and extraction of hydraulic pressure of a hydraulic cylinder.

5 Lift arm 7 Hydraulic cylinder 20 Hydraulic position lever 24 Restriction member 27 Spring member A Lift arm operation range B Hydraulic supply range

Claims (3)

A hydraulic position lever movable between a lift arm operating range for operating the lift arm of the tractor and a hydraulic pressure supplying range for supplying hydraulic pressure of the hydraulic cylinder to the outside; and the hydraulic pressure from the lift arm operating range to the hydraulic pressure supplying range A tractor lever operating structure comprising a restricting member for restricting movement of the position lever,
The restricting member restricts movement of the hydraulic position lever from the lift arm operating range to the hydraulic pressure supply range from a locked state that restricts movement of the hydraulic position lever from the lift arm operating range to the hydraulic pressure supply range. Can be manually switched to the non-locked state, and after the regulating member is manually unlocked and the hydraulic position lever is moved to the hydraulic pressure supply range, the hydraulic position lever is moved to the lift arm operating range. A tractor lever operating structure configured to allow the restricting member to automatically move to the locked state by allowing movement to the lift arm operating range when moved. A spring member for biasing the regulating member from the unlocked state to the locked state;
When the hydraulic position lever is positioned in the hydraulic pressure supply range, the non-locking restricting member comes into contact with a lateral side surface of the hydraulic position lever from a direction orthogonal to the moving direction of the hydraulic position lever, and The tractor lever operating structure according to claim 1, wherein the tractor lever operating structure is configured to be pressed against a lateral side surface of the hydraulic position lever by a spring member. Separately from the locked state and the non-locked state, the movement of the hydraulic position lever to the hydraulic pressure supply range is not restricted, and the position is not in contact with the lateral surface of the hydraulic position lever against the spring member. Set the intermediate state to hold the restriction member,
When the hydraulic pressure lever is moved from the lift arm operating range to the hydraulic pressure supply range with the regulating member set to the intermediate state, the regulating member is configured to change from the intermediate state to the unlocked state. The tractor lever operating structure according to claim 2.

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