JP2002097672A - Travel operation regulating device for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply constitute a lock member and the support means, and to increase a degree of freedom of arranging a control valve by lengthening an interlocking means. SOLUTION: A control lever 71 has a lever arm 33 projecting downward from a pivot part, an engaging part 39 is arranged in a lower part of this lever arm 33, the interlocking means 74 interlocked with and connected to a mechanical control valve C is connected to a midway part, the lock member 39 having an engaging object part 41 engaged with the engaging part 39 is arranged below this interlocking means 74, and a lock part 41b for locking the lever arm 33 in a neutral position and a lock releasing part 41a for allowing rocking of the lever arm 33 are formed in the engaging object part 41 of this lock member 38 to provide a lock releasing cylinder 43 operated by pressure oil supplied to a pilot operation valve, operating the lock member 38 to the lock releasing side and operating the lock member 38 to the lock side when unloading the pressure oil by operation of an unloading valve 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device for maintaining a work vehicle such as a backhoe in a stopped state.

[0002]

2. Description of the Related Art For example, a backhoe has hydraulic actuators such as a left and right running motor, a swing motor, a boom cylinder, an arm cylinder, and a bucket cylinder, and each is controlled by operating a control valve. A pilot control valve is used as a control valve of a hydraulic actuator such as the swing motor, the boom cylinder, the arm cylinder, and the bucket cylinder. The pilot control valve is controlled by a pilot operation valve operated by an operation lever. Has become.

The pilot operation valve is supplied with pilot pressure oil from a hydraulic pump via a pilot pressure supply oil passage. The pilot pressure supply oil passage is provided with an unload valve for unloading, and a backhoe is provided. The control valve is unloaded so that unintentional actuator operation does not occur, for example, when the operator gets off the vehicle. The control valve of the left and right travel motor is mechanical (mechanical)
A control valve is used, and the mechanical control valve is operated by a left / right traveling control lever through mechanical interlocking means such as a link and a rod.

In order to prevent undesired operation of the traveling control lever, a neutral lock means for restricting the movement of the control lever itself or a member interlockingly connected to the control lever is provided. As this prior art, utility model registration No. 569
No. 397 is disclosed. This is achieved by operating a traveling unit hydraulic switching valve (mechanical control valve) that is directly operated by a traveling unit operating tool (traveling control lever) to supply hydraulic oil from a hydraulic pump and a working unit operating tool. A working unit hydraulic switching valve (pilot type control valve) in which a pilot oil is supplied indirectly from a hydraulic pump through a pilot operation indirectly via a pilot valve. When the operation is locked, the operation is provided between the hydraulic pump and the pilot valve. When the safety lock lever is unlocked, the hydraulic oil is supplied to the pilot valve. An unload valve that switches to disable the pilot operation of the working unit hydraulic switching valve by cutting off the supply of pressure oil to the valve, A double-acting type pilot, in which both cylinder chambers are communicated via orifices, An unlocking cylinder connected to the valve in parallel with the oil passage, wherein the unlocking cylinder and the engaging tool move the engaging tool to the disengagement side against the elastic machine in a state where the hydraulic oil is supplied. The cylinder is operated to move the engaging member to the engaging side by receiving the urging force of the elastic body when the supply of the pressure oil is cut off. "

[0005] In this prior art, not only when the safety lock lever is locked, but also when the engine is stopped in a state where the supply of pressure oil is stopped, even if the safety lock lever is in the unlocked position, the vehicle travels. The operating tool is maintained in the locked state, so that the operating tool is not inadvertently operated to the traveling position. " The mechanism that regulates the traveling operation includes a swing plate (lock member) that can be disengaged from a projecting pin projecting from a base end of the left and right traveling lever (traveling control lever). It consists of a return spring that constantly urges the plate toward the engagement side, a lock release cylinder that forcibly swings the swinging plate toward the disengagement side, and the like. While the plate is separated from the protruding pin to allow operation of the left and right traveling levers, while the unlocking cylinder is extended, the swinging plate engages with the protruding pin to regulate the operation of the left and right traveling levers. ,
The unlocking cylinder is linked with the operation of the unloading valve. "

[0006]

In the above prior art, a protruding pin is provided above a pivot portion of a traveling control lever, and a large force from the control lever is applied to the lock member. The means must be configured to be robust, and a link that is interlockingly connected to the control valve is connected to the arm that protrudes downward from the pivot, and the position at which the control valve can be arranged is difficult because the interlocking means is difficult to configure long. Limited, the locking member has only a concave portion that engages with the protruding pin, so it is difficult to secure the engagement relationship, and a member that sets the operation range of the control lever is indispensable, and the operation timing of the lock release cylinder is also required. It is difficult to adjust.

[0007] It is an object of the present invention to provide a work vehicle traveling operation restricting device which can solve such problems of the prior art. The present invention provides a simple structure of a lock member and a supporting means thereof, an extended interlocking means to increase a degree of freedom of arrangement of a control valve, a securing of a relationship between a protruding pin and a lock member, and a control of a control lever. It is an object of the present invention to provide a traveling operation restricting device for a working vehicle in which a member for setting a range can be omitted.

[0008]

A first concrete means for solving the problem in the present invention is a mechanical control valve C1 operated by a control lever 71 to control a hydraulic traveling motor 3 of a work vehicle 51. , C2, a pilot-type control valve C controlled by a pilot pressure from the pilot-operated valve 19 to control a hydraulic actuator on the work vehicle 51, and a pilot-operated valve 19 when the operation of the hydraulic actuator is stopped. An unload valve 18 for unloading the supplied pressure oil, and the control lever 71
Has a lever arm 33 projecting downward from the pivot,
An engaging portion 39 is provided at a lower portion of the lever arm 33, and an interlocking means 74 for interlockingly connecting with the mechanical control valve C is connected at an intermediate portion. A lock member 38 having an engagement portion 41 is arranged,
The lock member 38 is provided on the engaged portion 41 with the lever arm 33.
A lock portion 41b for locking the lock member at a neutral position and a lock release portion 41a for permitting the swing of the lever arm 33. The lock member 38 is actuated by pressure oil supplied to the pilot operation valve 19 to move the lock member 38 to the unlock side. And a lock release cylinder 43 for operating the lock member 38 to the lock side when the pressure oil is unloaded by the operation of the unload valve 18.

As a result, the configuration of the lock member 38 and the support means thereof is simplified, the length of the interlocking means 74 is increased and the degree of freedom of arrangement of the control valves C1 and C2 is increased. The engagement relationship between the engaged portions 41 can be favorably maintained. A second specific means for solving the problem in the present invention is that, in addition to the first specific means, the lock member 38 is formed in a substantially L-shape in a side view, and the corner portion has a shaft 3.
7 pivotally supports the engaging portion 3 of the lever arm 33 from the engaged portion 41 of the one end portion 38A to the corner portion.
9 substantially along the swing direction.

As a result, the structure of the lock member 38 and the support means for the lock member 38 becomes simpler and less expensive, and the durability is improved. A third specific means for solving the problem in the present invention is that, in addition to the first or second specific means, the lock member 38 has an end portion 38B which is linked to a lock release cylinder 43.
And an adjusting member 40A for adjusting the operation timing. This makes it possible to properly lock and release the lock member 38.

A fourth concrete means for solving the problem in the present invention is that, in addition to any one of the first to third concrete means, the engaging portion 39 is formed by a projecting pin, and The portion 41 is such that the lock release portion 41a is formed by a horizontal groove for guiding the movement of the projection pin, and the lock portion 41b is formed by a vertical groove intersecting the horizontal groove and engaging with the projection pin. Thereby, the engagement relationship between the engagement portion 39 and the engaged portion 41 can be ensured and maintained more favorably.

A fifth concrete means for solving the problem in the present invention is that, in addition to the fourth concrete means, the lateral groove of the engaged portion 41 is provided when both ends of the control lever 71 are swung to the maximum. That is, it can be brought into contact with the engaging portion 39. This makes it possible to omit the member for setting the operation range of the operation lever 71.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 6 to 8, reference numeral 51 denotes a backhoe exemplified as a working vehicle.
Is mainly composed of an upper swing body 52 and a lower traveling device 53. The traveling device 53 includes a pair of left and right traveling members 54 of a rubber crawler type driven by the hydraulic traveling motor 3 and a dozer 55 at a front portion. The revolving superstructure 52 includes a revolving base 56 supported on a traveling device 53 so as to be rotatable left and right around an axis S in a vertical direction, a working device (excavator) 57 provided in front of the revolving base 56, Stand 5
6 is provided with a driver's seat 58 and the like.

A rear portion of the turntable 56 has a counterweight 59 for balancing the weight with the working device 57 and the like. An engine 13, a radiator 68, a multiple hydraulic pump P, Air cleaners and the like are arranged, and these are covered by a bonnet 61 pivotally supported at the front upper part. A hydraulic oil tank 70 for storing hydraulic oil of hydraulic equipment, a number of control valves C for controlling hydraulic equipment, and the like are disposed on the right side of the swivel 56, and these are covered by a tank cover 62.

A support bracket 63 is provided at the front of the turntable 6.
The swing bracket 64 is supported on the support bracket 63 so as to be swingable right and left around the vertical axis. The working device 57 includes a boom 65 whose base portion is swingably supported by the swing bracket 64 and an arm 66 whose base portion is swingably supported by the distal end side of the boom 65.
And a bucket 67 supported on the distal end side of the arm 66 so as to be able to perform a squeeze dump operation. The bucket 67 can be operated by a boom cylinder 4, an arm cylinder 6, and a bucket cylinder 5, each of which is a hydraulic cylinder. I have.

The driver's seat 58 is arranged on the front side of the hood 61 and on the left side of the tank cover 62, and is detachably mounted on a seat support 73. The seat support 73 is detachable from the swivel 56. In front of the driver's seat 58, a pair of left and right traveling control levers 7 are provided to separately operate the left and right traveling bodies 54.
1L and 71R are disposed, and control tables (control devices) 72L and 72R are disposed on both left and right sides of the driver's seat 58. These left and right control tables 72L and 72R are seat supports 73.
It is removably attached to and fixed to.

The left control table 72L is rotatable upward (upward) about a left-right axis about a rear pivot point. This corresponds to the left side of the driver's seat 58 (the front left side of the driver's seat 58, that is,
(The front side of the vehicle) is an entrance 82, and the left control table 72L is pivoted upward around the pivot point so as not to obstruct the entrance and exit, so that the entrance 82 is retracted so as to widen the entrance 82. It was made possible. Note that the right control table 72R may also be rotatable upward. On the right control table 72R, a boom / bucket operation lever 76 for operating the boom 65 and the bucket 67, a dozer operation lever 77 for operating the dozer 55, an accelerator lever 78 for controlling engine rotation, and a right lock A lever 79R is provided.

When the right lock lever 79R is operated upward, the changeover switch 83R is operated to turn off the unload valve 18 to be described later, and the boom 65 and the bucket 67 are operated by the boom / bucket operation lever 76.
Operation is disabled. In addition, on the right control console 72R,
Control valve C for boom cylinder 4 and bucket cylinder 5
3, a pilot operation valve 19R for controlling C4 is mounted and supported, and the pilot operation valve 19R is operated so that
The boom / bucket operation lever 76 is provided.

A turning motor 7 and an arm 66 for turning the turning table 56 around the turning center S are provided on the left control table 72L.
, And a left / right lock lever 79L. When the left lock lever 79L is operated upward, the changeover switch 83
L to turn off the unload valve 18 to be described later, rotate the left control table 72L upward, and disable the operation of the swing motor 7 and the arm 66 by the swing / arm operation lever 80. I do.

The left and right lock levers 79L and 79R are
Together with the changeover switches 83L and 83R (shown in FIG. 5),
The stop operation means 26 which is operated when the operation of the backhoe 1 is brought into the stop state is constituted. When the left lock lever 79L is operated downward, the left control table 72L is lowered, and the operation of the turning motor 7 and the arm 66 by the turning / arm operation lever 80 is enabled. The pilot control valve 19L that controls the control valves C5 and C7 for the swing motor 7 and the arm cylinder 6 is provided with a left-side control table 72L.
The pivot / arm operation lever 80 is provided so as to operate the pilot operation valve 19L.

In the hydraulic system of the backhoe 51 shown in FIGS. 3 and 4, the engine 13 uses four hydraulic pumps P1,
P2, P3, and P4 are driven, and the hydraulic oil of the dual variable displacement main hydraulic pumps P1 and P2 is supplied via the control valves C1 and C2 to the traveling motors 3L,
3R and control valves C3, C4, C5, C6
Through the first working actuator such as the boom cylinder 4, bucket cylinder 5, arm cylinder 6, and service actuator (attachment) 10.

The service actuator 10 is a breaker, an auger, a cutter, or the like, and has various hydraulic capacities. The service actuator 10 is detachably connected to the service port 14 of the backhoe. The main hydraulic pump P1, the control valve C1,
A first hydraulic circuit is formed by the traveling motor 3R, the control valves C3 and C4, the boom cylinder 4, the bucket cylinder 5, and the like. The main hydraulic pump P2, the control valve C2, the traveling motor 3L, the control valves C5 and C6, the arm The second hydraulic circuit is formed by the cylinder 6, the service actuator 10, and the like, and the boom cylinder 4, the bucket cylinder 5, the arm cylinder 6, the service actuator 10, and the like are the first type work actuator.

The hydraulic oil from the third sub-hydraulic pump P3 is supplied to the swing motor 7, via the control valves C7, C8 and C9.
It can be supplied to the second-type working actuators such as the swing cylinder 8 and the dozer cylinder 9 and can also be supplied to the switching diversion valve 11, and these form a third hydraulic circuit. The switching diversion valve 11 is of a two-position switching type between a distribution position and a diversion supply position, and when operated to the diversion supply position, communicates with the two oil passages 24 and 25 to equally divide the pressure oil of the sub hydraulic pump P3. Supply to the oil passages 24 and 25 becomes possible.

The divided stream of the pressure oil of the sub hydraulic pump P3 can be supplied to the boom cylinder 4 and the bucket cylinder 5 through the oil passage 24 through the control valves C3 and C4, and the main hydraulic pump P1 Is supplied to the suction side of the control valve C1 to which the pressurized oil is supplied, so that the traveling motor 3R can be driven. The divided other flow passes through the oil passage 25 via the control valves C5 and C6, and the arm cylinder 6, In addition to being able to supply the service actuator 10, the pressure oil of the main hydraulic pump P2 is supplied to the suction side of the control valve C2 to be supplied, and the traveling motor 3L can be driven.

The control valves C3, C4, C5, C7 and the switching diverting valve 11 are of a hydraulic pilot switching type.
Pressure oil from the pilot pressure hydraulic pump P4 passes through the pilot pressure supply oil passage 22, passes through the swash plate angle changing travel speed switching valve 17, the unload valve 18, and passes through the pilot operation valves 19L, 19R, and the control valve. C3, C4, C5, C
7 and is switched via an oil passage 20
1 is supplied. A pilot pressure control oil passage 21 is connected to the oil passage 20 of the switching flow dividing valve 11. The pilot pressure control oil passage 21 is provided between the left and right traveling motor 3
It has a first control oil passage 21A that drains oil through the L and 3R control valves C1 and C2, and a second control oil passage 21B that drains oil from the oil passage 20 through the control valves C1 to C6.

In the hydraulic system, when the left and right traveling motors 3L and 3R are not driven without operating the control valves C1 and C2, the oil of the main hydraulic pump P1 can be supplied to the boom cylinder 4 and the bucket cylinder 5, The oil of the pump P2 can be supplied to the arm cylinder 6 and the service actuator 10, and the oil of the sub-hydraulic pump P3 can be supplied to the swing motor 7, the swing cylinder 8, and the dozer cylinder 9. Control valve C for straight running
By operating 1, C2, the oil of the main hydraulic pumps P1, P2 is supplied to and drives the left and right traveling motors 3L, 3R, and the pilot pressure control oil passage 21 is blocked by switching the control valves C1, C2. When the pilot pressure rises, the switching diversion valve 11 is operated to change the distribution position to the diversion supply position, and the oil of the sub hydraulic pump P3 is supplied to the right traveling motor 3
R, left running motor 3L, boom cylinder 4, bucket cylinder 5, arm cylinder 6, and service actuator 10 can be supplied.

Accordingly, at this time, the second type working actuators of the swing motor 7, the swing cylinder 8 and the dozer cylinder 9 are in an operable state, and the boom cylinder 4, the bucket cylinder 5, the arm cylinder 6 and the first The seed actuators are also in an operable state, and if they are not operated, all the oil of the sub hydraulic pump P3 is supplied to the left and right traveling motors 3L, 3R, and the speed is increased more than when only the main hydraulic pumps P1, P2 are used. You. The switching diversion valve 11, the oil passages 24 and 25 from the switching diversion valve 11 to each control valve C, the oil passage 20, the pilot pressure control oil passage 21 and the like are provided with left and right traveling motors 3L and 3R.
Is switched to drive, the switching diverting valve 11 is operated, and the hydraulic oil from the sub hydraulic pump P3 is supplied with the left and right traveling motors 3L, 3R, the boom cylinder 4, the bucket cylinder 5, the arm cylinder 6, and the service actuator 10
And a switching means for supplying the data to the power supply.

The switching means includes a switching diversion valve 11
Boil cylinder 4, bucket cylinder 5, arm cylinder 6 and service actuator 10
The left and right traveling motors 3L, 3L
R, or by providing a switching diversion valve 11 between the sub-hydraulic pump P3 and the control valve 8 so that the oil of the sub-hydraulic pump P3 is not supplied to the second-type working actuator during straight running. Alternatively, only the left and right traveling motors 3L and 3R may be supplied. Further, the switching means may be configured to perform only the function of simultaneously supplying an equal amount of oil to the left and right traveling motors 3L and 3R, and not to supply the oil of the sub hydraulic pump P3.

The unload valve 18 is connected to a pilot hydraulic operation system, and has left and right lock levers 79L, 79L.
When the changeover switches 83L and 83R are turned off by 9R, the pilot hydraulic operation system (pilot pressure supply oil passage 22) is unloaded, and the traveling device 53, the turning motor 7 of the turning table 56, the hydraulic cylinder of the excavator 57, and the like are unloaded. The supply of pressure oil is stopped. Control valves C1, C
2, C6, C8 and C9 are manual operation switching types, and the traveling control valves C1 and C2 are traveling traveling levers 71L and 71R.
The control valve C6 is operated by a service port switching lever, the control valve C8 is operated by a swing pedal (not shown), and the control valve C9 is operated by a dozer operating lever 77.

The traveling control levers 71L and 71R are
As shown in FIG. 6, the spools of the traveling control valves C1 and C2 are mechanically and interlocked with each other via interlocking means 74 including an arm, a link, a rotating body or the like, or interlocking means such as a push-pull cable. I have. In FIGS. 1 to 8, a control stand 28 is detachably bolted to a substrate 56 </ b> A of a swivel base 56, and the control stand 28 has a left and right support plate 3 on a base plate 29.
0, two relay support shafts 31 and the like are erected, and the control levers 71L, 7 are mounted on the horizontal shaft 32 fixed above the left and right support plates 30.
Each boss portion 71a, 71b of 1R is rotatably supported.

The boss portions 71a and 71b of the control levers 71L and 71R have lever arms 33 protruding downward.
L and 33R are fixed so as to be rotatable integrally, and a link 34 of the interlocking means 74 is connected to an intermediate portion in the vertical direction. The horizontal axis 32 serves as a pivot for the control levers 71L and 71R. The interlocking means 74 includes two relay shafts 31
A rotating body 35 (bell crank shape) having two arms protruding in different directions from the boss portion is supported rotatably about the vertical axis, and is linked to one arm 35a of each of the rotating bodies 35. 34 and the other arm 35b
The link 36 connected to each spool of the control valves C1 and C2
Are connected.

A lock member 38 is pivotally supported below the left and right support plates 30 via a lower shaft 37. This lock member 3
Reference numeral 8 denotes a substantially L-shaped side view, the corner portion of which is fitted to the lower shaft 37, and a substantially T-shaped engaging groove (engaged portion) 41 is provided at one end 38A located substantially horizontally. And the other end 38
B has a contact portion 40. The engagement groove 41 is a lateral groove (lock release portion) substantially along the swing direction of the lever arm 33.
41a, and a vertical groove (lock portion) 41b formed at the center of the horizontal groove 41a.

The engaging groove 41 is engaged with a projecting pin (engaging portion) 39 provided below the lever arm 33. When the projecting pin 39 is engaged with the lateral groove 41a of the engaging groove 41. The swing of the lever arm 33 and the control levers 71L and 71R is allowed (unlocked state), and the lever arm 3
When the lock member 38 swings clockwise in FIG. 1 and the projection pin 39 engages with the vertical groove 41b of the engagement groove 41 in a state where the control levers 71L and 71R are in the neutral position, the lever arm 33 and The swing of the control levers 71L and 71R is restricted (locked state).

The lock member 38 is urged clockwise in FIG. 1 by a tension spring (ramper) 42.
The contact part 40 is a pilot-operated lock release cylinder 4.
3 is in contact with the tip of the piston rod 43A. The lever arm 33, the lock member 38, the tension spring 42, the lock release cylinder 43, and the like constitute a neutral lock means 45 for locking and releasing the control levers 71L, 71R at the neutral position. The lock release cylinder 43 is of a single-acting type and communicates with the pilot pressure supply oil passage 22 through a pilot oil passage (piping) 44. The cylinder 43 is a piston rod 43
A is projected, and the lock member 38 swings counterclockwise in FIG. 1 against the tension spring (elastic machine) 42 to engage the projection pin 39 with the lateral groove 41 a of the engagement groove 41.

The lock release cylinder 43 has a communication hole 4 for communicating the push rod side and the rod side with the piston rod 43A.
3a is formed so that the piston rod 43A can smoothly return. Accordingly, when the lock lever 79 is lifted to bring the unload valve 18 into the unloaded state, or when the engine 13 is stopped and the unload valve 18 is turned off, if the pressure oil in the pilot pressure supply oil passage 22 is released, The pressure oil in the pilot oil passage 44 also escapes, and the lock member 38 is pulled by a tension spring (arm) 42.
1, the vertical groove 41 b of the engagement groove 41 engages with the projection pin 39, and the control levers 71 L, 71
This restricts the 1R from swinging from the neutral position, and locks the traveling control operation to an impossible state.

In this locked state, the control lever 7
When a swinging force is applied to 1L and 71R, the force is transmitted to one end 38A of the lock member 38 and is supported by the lower shaft 37. However, since the projection pin 39 is at the lowermost end of the lever arm 33, The force is smaller than in the other positions, and the load is reduced since the force is directed to the lower shaft 37. Therefore, the lock member 38 and the like can be manufactured at low cost without being damaged. The link 34 is connected to a middle portion of the lever arm 33, and the lever arm 33 has a lock release cylinder 43 and the like located below the lever arm 33, and is disposed relatively upward. The control valve C can be arranged without being obstructed by the structure, and can be arranged at various positions without being restricted by the position near the control levers 71L and 71R.

Further, since the control levers 71L and 71R, the lock member 38, the lock release cylinder 43, the relay support shaft 31 and the like are arranged on the base plate 29, the control table 28 having these can be configured as a unit. The units can be assembled in advance and assembled on the substrate 56A of the swivel base 56, so that the assembly can be facilitated. Reference numeral 46 denotes a stopper for restricting the maximum swing of the lever arm 33. The stopper 46 is attached to the support plate 30 so as to face the lever arms 33L and 33R, and can adjust the maximum swing amount of the lever arm.

The maximum swing range of the lever arm 33 is as follows.
Since the projecting pins 39 abut on both ends of the lateral groove 41a of the engaging groove 41, they can be set by the length of the lateral groove 41a, and the stopper 46 can be omitted.
If it is desired to adjust the swing amount of the lever arm, it may be provided. In FIG. 1, reference numeral 47 denotes a front cover at the front of the swivel base 56, and reference numeral 48 denotes a floor sheet at the top of the swivel base 56. Reference numeral 49 denotes a mounting plate fixed on the base plate 29 of the pilot table 28, which supports and reinforces a middle portion of the relay support shaft 31, and also supports a pipe forming the pilot oil passage 44.

In FIG. 2, reference numeral 50 denotes a speed-increasing pedal pivotally supported by the support plate 30. When the pedal is depressed, the traveling speed switching valve 17 for changing the swash plate angle is actuated via a switch, and the traveling motor 3 is turned on. It can be switched from low speed to high speed. FIG. 9 shows a second embodiment, in which the stopper for the lever arm 33 is omitted, the abutting portion 40 of the other end 38B of the lock member 38 is formed by an adjusting member (screw) 40A, The engagement between the (engaging portion) 39 and the lateral groove (unlocking portion) 41a and the vertical groove (locking portion) 41b of the engaging groove (engaged portion) 41 can be adjusted so as to be appropriate.

The present invention is not limited to the above embodiment, but can be variously modified. For example,
In the first and second embodiments, the lock member 38 may be provided with the projection pin 39 and the lever arm 33 may be provided with the engagement groove 41 so that the relationship between the engagement portion and the engaged portion may be reversed. The left and right traveling control valves C1 and C2 are lock levers 79L and 79R.
It may be configured such that only one of them is locked by the upward rotation operation. As the stop operation means 26, a lever, a switch, or the like may be provided instead of or in addition to the lock levers 79L, 79R. Instead of providing the tension spring 42 for applying the urging force, the lock release cylinder 43 may be moved backward.

[0041]

According to the present invention described in detail above, the structure of the lock member 38 and its supporting means (the lower shaft 37 and the like) can be simplified, and the interlocking means 74 can be lengthened to arrange the control valves C1 and C2 freely. The degree can be increased.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of a main part showing an embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a cross-sectional side view of a control lever locked state.

FIG. 4 is an overall hydraulic circuit of a work vehicle.

FIG. 5 is a hydraulic circuit diagram of a main part provided with neutral locking means.

FIG. 6 is a plan view of the backhoe.

FIG. 7 is a side view of the backhoe.

FIG. 8 is a perspective view of a backhoe.

FIG. 9 is a cross-sectional side view of a main part showing the second embodiment.

[Explanation of symbols]

 3 Traveling Motor 18 Unload Valve 19 Pilot Operated Valve 22 Pilot Pressure Supply Oil Path 28 Pilot 31 Relay Support Shaft 32 Horizontal Shaft 33 Lever Arm 37 Lower Shaft 38 Lock Body 39 Projection Pin (engagement) 41 Engagement Groove Engaging part) 41a Horizontal groove (unlocking part) 41b Vertical groove (locking part) 42 Tension spring (ramper) 43 Unlocking cylinder C Control valve 51 Backhoe (working vehicle) 52 Turning table 53 Traveling device 71 Traveling control lever 74 Interlocking means 79 Lock lever

Claims (5)

[Claims] 1. A mechanical control valve operated by a control lever to control a hydraulic traveling motor of a work vehicle, and a pilot controlled by a pilot pressure from a pilot operation valve to control a hydraulic actuator on the work vehicle. A control arm, and an unload valve for unloading the pressure oil supplied to the pilot operation valve when the operation stop of the hydraulic actuator is maintained, wherein the control lever protrudes downward from a pivot portion. An engaging portion is provided at a lower portion of the lever arm, and an interlocking means for interlockingly connecting with the mechanical control valve is connected at an intermediate portion, and the engaged portion engaged with the engaging portion below the interlocking means is provided. A locking member for locking the lever arm to the engaged portion in the neutral position, and a locking member for allowing the lever arm to swing. A lock member is actuated by the pressure oil supplied to the pilot operation valve to actuate the lock member to the unlocking side, and the lock member is locked when the pressure oil is unloaded by actuation of the unload valve. A travel operation restricting device for a work vehicle, comprising a lock release cylinder operated on a side of the vehicle. 2. The lock member is formed in a substantially L-shape in a side view, and a corner portion is pivotally supported by a shaft so as to be swingable.
2. The device according to claim 1, wherein a portion from the engaged portion at one end to the corner portion is substantially along a swing direction of the engaging portion of the lever arm.
A travel operation restricting device for a working vehicle according to claim 1. 3. The travel operation restricting device for a working vehicle according to claim 1, wherein the lock member has an adjustment member for adjusting an operation timing at an end portion linked to a lock release cylinder. . 4. The engaging portion is formed by a protruding pin, the engaged portion is formed by a lateral groove in which an unlocking portion guides the movement of the protruding pin, and the locking portion intersects the lateral groove and engages with the protruding pin. The travel operation restricting device for a working vehicle according to any one of claims 1 to 3, wherein the driving operation restricting device is formed by vertical grooves that match. 5. The traveling operation restriction of a working vehicle according to claim 4, wherein the lateral groove of the engaged portion can be brought into contact with the engaging portion when both ends of the horizontal lever swing the control lever. apparatus.