JP2008104369A - Working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extended leveling portion extending from a main leveling portion to the left and right direction outward from a lower level side of a rear cover, and the extended leveling portion can be switched between an extended posture and a retracted posture by remote control. , The operation force when switching the extended leveling portion between the extended posture and the retracted posture is reduced.
A push member 40 is provided for changing the posture of the extended leveling section 23 from the extended posture B to the retracted posture C by rotating, and the extended leveling portion 23 is rotated from the extended posture B to the retracted posture C side. The retracting operation spring 41 for urging the pushing member 40 is provided, and is provided across the pushing member 40 and the extended leveling portion 23. In the extended posture B, the retracting operation spring 41 is applied in a direction to press the extended leveling portion 23 against the farm field. A holding spring 45 is provided.
[Selection] Figure 1

Description

  The present invention relates to a working machine having a leveling function such as a rotary tiller.

Conventionally, there is a rotary cultivator as a working machine having a leveling function, and the rotary cultivator is mounted on a rear part of a tractor through a mounting device such as a three-point link machine so as to be movable up and down. There is provided a rotary tiller part in which a number of tillage claws are attached to a claw shaft provided rotatably around a horizontal axis in the lower part, and a tillage cover that covers the rotary tiller part.
The rotary cover includes a main cover that covers the upper side of the rotary tillage part and a rear cover that covers the rear side of the rotary tillage part, and a leveling part that grounds the farm field by grounding the farm field is provided on the lower end side of the rear cover. ing.

As the leveling part, a main leveling part corresponding to the left and right width of the main part of the rear cover, and an extended leveling provided on both the left and right sides of the main leveling part and extending outward in the left-right direction from the main leveling part The extended leveling portion is rotatably supported by the main leveling portion, and is rotated from the extended posture to the retracted posture located on the back side of the main leveling portion. It can be changed.
Also, as a rotary tiller, during tilling in the extended posture, even if the extended leveling part is pushed up by the pressing force from the soil and rotated to the retracted posture side, it can always return to the extended posture, There is one in which the extended leveling portion is always urged in the direction of rotating from the retracted posture to the extended posture by the urging means (see Patent Document 1).
Japanese Patent Laid-Open No. 2005-130824

In the conventional rotary cultivator, the urging force of the urging means for urging the extended leveling portion to the extended posture requires a large urging force to suppress soil, and the extended leveling portion is The biasing force of the biasing means that biases the extended leveling portion as the extended leveling portion is rotated from the extended posture to the retracted posture is constantly biased in the direction of rotating from the retracted posture to the extended posture. There is a problem that the operation force is increased when the extended leveling portion is changed from the extended posture to the retracted posture (when the extended leveling portion is switched between the extended posture and the retracted posture).
Therefore, in view of the above problems, an object of the present invention is to provide a working machine that reduces the operating force when the extended leveling portion is switched between the extended posture and the retracted posture.

  The technical means taken by the present invention to solve the technical problem is that the leveling part for leveling the field is a main leveling part, and an extended leveling that extends outward from the main leveling part in the left-right direction. The extended leveling part is rotatable with respect to the main leveling part, and can be changed in posture from the extended position to the retracted position located on the back side of the main leveling part by rotating. A pushing member that changes the posture of the extended leveling portion from the extended posture to the retracted posture when rotated, and biases the pushing member to rotate the extended leveling portion from the extended posture to the retracted posture side. A biasing means for retraction operation, and an extension leveling part restraining biasing means that is provided across the pushing member and the extended leveling part and biases the extended leveling part in a direction to press the extended leveling part against the field in the extended posture. It is characterized by.

  In addition, an operation wire for remotely operating the pusher member is provided, and this operation wire is mainly composed of an inner wire whose one end is connected to the pusher member and an outer wire that guides the inner wire. When the inner wire is pulled while the part is in the retracted position, the pushing member rotates and the extended leveling member follows the pushing member to the extended position by the biasing force of the extension leveling part restraining biasing means. The push wire connecting side of the operation wire is disposed substantially along the main leveling portion, and the extended leveling portion is in the extended posture at one end side of the inner wire. It is good to be connected with the pushing member between the rotation fulcrum of the pushing member and the main leveling part.

  According to the present invention, the extended leveling portion is rotated from the extended posture to the retracted posture side by the biasing force of the biasing means for the retracting operation, and it is the extension that biases the extended leveling portion in the direction of pressing against the farm field. Since it is performed by the urging force of the grading portion restraining urging means, even if the urging force for urging the extended grading portion against the field is sufficiently large, the extended grading portion is rotated to the retracted posture. Since the urging force for this can be set to the minimum necessary urging force, it is possible to reduce the operating force when the extended leveling portion is switched between the extended posture and the retracted posture.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 6, reference numeral 1 denotes a rotary cultivator exemplified as a working machine that is mounted on the rear part of the tractor so as to be movable up and down via a three-point link mechanism or the like.
The rotary cultivator 1 has support arms 3 projecting from the center gear case on the left and right sides, fixing the upper part of the transmission case 4 to the left and right outer ends of one support arm 3, and the left and right sides of the other support arm 3. The upper part of the side frame is fixed to the outer end side in the direction, and the machine casing 5 is mainly configured in a gate shape.

A top mast 6 is fixed to the gear case of the machine frame 5 so as to protrude upward, and an upper connection bracket 7 is provided on the top mast 6 so as to protrude forward and upward. An upper mounting pin 8 is provided that is attached to the upper end of a connecting frame connected to the rear end side of the top link of the point link mechanism or the rear end side of the three-point link mechanism.
Each of the left and right support arms 3 of the machine frame 5 is provided with a lower connection bracket 9, and the lower end of the lower connection bracket 9 has a rear end of the lower link of the three-point link mechanism or a rear of the three-point link mechanism. A lower mounting pin 10 is provided to be attached to the lower part of the connecting frame connected to the end side.

A lower part of the machine casing 5 has a claw shaft 11 that is supported between the lower part of the transmission case 4 and the side frame so as to be rotatable about a lateral axis, and a number of attachments attached to the claw shaft 11. A rotary tiller 13 including the tilling claws 12 is provided.
The gear case of the machine frame 5 is provided with a PIC shaft 14 to which power is transmitted from the PTO shaft of the tractor via the drive shaft. The power transmitted to the PIC shaft 14 is a power transmission mechanism in the gear case. It is transmitted to the claw shaft 11 through the transmission shaft in the support arm 3 and the power transmission mechanism in the transmission case 4, and the claw shaft 11 is configured to be driven to rotate in the direction indicated by the arrow A, for example.

The rotary tiller 1 is provided with a rotary cover 15 that covers the rotary tiller 13. The rotary cover 15 covers an upper cover 16 that covers the top of the rotary tiller 13 and a rear of the rotary tiller 13. A rear cover 17 for covering and a side cover 18 for covering the left and right sides of the rear portion of the rotary tiller 13 are provided.
The upper cover 16 is attached and fixed to the transmission case 4 and the side frame at the ends in the left-right direction.
The rear cover 17 is pivotally supported on the rear end side (machine frame 5 side) of the upper cover 16 so as to be rotatable about the axis of a pivot 19 having a horizontal axis, and can swing up and down. Reinforcing members 20 are provided on the left and right sides of the rear surface of the rear cover 17 from the upper side to the lower side of the rear cover 17.

The side cover 18 is fixedly attached to the transmission case 4 or the side frame.
The rotary cultivator 1 is provided with a retracting device that urges the lower end side of the rear cover 17 downward (in the direction of grounding), and a support frame for attaching a gauge wheel, a cultivator, a vertical stand, etc. Is provided.
In the present embodiment, as shown in FIG. 4, the rear cover 17 mainly includes a main portion 21 that is a portion that receives soil discharged from the tilling portion 13, and left and right sides of the lower portion of the main portion 21. It is mainly composed of a pair of left and right closing covers 22 that closes the notches formed at both ends and on the outer side in the left and right direction of the reinforcing member 20, and an extended leveling portion 23 provided on each of the left and right closing covers 22. Yes.

As shown in FIG. 7, the main portion 21 of the rear cover 17 and the lower end side of the closing cover 22 and the extended leveling portion 23 are formed in a groove shape whose rear side is open toward the rear (front side). It is a curved shape that is convex toward the surface).
The main portion 21 of the rear cover 17 and the front surface of the lower end side of the closing cover 22 and the front surface of the extended leveling portion 23 are grounded so as to level the soil cultivated by the tilling portion 13. The main ground leveling portion 24 corresponding to the left and right width of the main portion 21 of the rear cover 17 is composed of the ground leveling portion on the side and the grounding portion on the lower end side of the closing cover 22. A leveling portion 25 of the rear cover 17 is configured.

As shown in FIGS. 3 and 4, the extended leveling portion 23 includes an extended posture B that extends outward from the main leveling portion 24 in the left-right direction, and a back side (anti-grounding side) of the main leveling portion 24. The main leveling portion 24 is pivotally supported by the main leveling portion 24 so that the posture can be changed to the retracted posture C positioned at (in the present embodiment, the extended leveling portion 23 is attached to the closing cover 22 and the closing cover 22 Is extended outward from the lower side in the left-right direction to be an extended posture B).
In the extended posture B, the left and right inner end sides of the extended leveling portion 23 are in contact with the left and right outer ends of the lower portion of the closing cover 22, and in the retracted posture C, the extended leveling portion 23 is superimposed on the closing cover 22. Is located.

Further, the left and right extended leveling portions 23 are interlocked and connected to an operation lever (operation member) 26 supported by the top mast 6 so as to be swingable around a left and right axis via an operation wire 27. By swinging the lever 26, the left and right extended leveling portions 23 can be simultaneously changed to the extended posture B and the retracted posture C.
The operation lever 26 can be gripped from the driver seat side of the tractor by raising the rotary tiller 1, whereby the extended leveling portion 23 can be remotely operated from the driver seat of the tractor.

  The operation wire 27 is composed of a push-pull wire, a Bowden wire, or the like, and is mainly composed of an inner wire 28 and an outer wire 29 that guides the inner wire 28. One end side of the inner wire 28 is on the extended leveling portion 23 side (extension) The other end side of the inner wire 28 is connected to the operation lever 26 side, and one end side of the outer wire 29 is connected to the lower end side of the reinforcing member 20 on the rear surface of the rear cover 17. The outer wire 29 is attached and fixed to the outer receptacle 30 provided, and the other end of the outer wire 29 is attached to and supported by an outer attachment bracket 31 provided on the top mast 6 so as to be rotatable about the left and right axis.

When the operating lever 26 is located at the retracting operation position D indicated by the solid line in FIG. 6, the extended leveling portion 23 is in the retracting position C, and the operating lever 26 is moved from the retracting operation position D to the imaginary line in FIG. When the extended leveling portion 23 is operated to change the posture from the retracted posture C to the extended posture B by swinging to the extended operation position E shown, and when the operating lever 26 is returned from the extended operation position E to the retracted operation position D. The extended leveling portion 23 is configured to be changed in posture from the extended posture B to the retracted posture C.
The operation lever 26 is in contact with the outer mounting bracket 31 to restrict movement in the swinging direction from the extended operation position E to the retreat operation position D, and the extended leveling portion 23 is held in the retreat posture C. When the operating lever 26 is hooked on the stopper 32 provided on the top mast 6 at the extended operation position E, the movement in the swinging direction from the extended operation position E to the retracting operation position D is restricted, and the extended leveling is performed. The portion 23 is configured to be held in the extended posture B.

As shown in FIG. 7, the lower end side of the main portion 21 of the rear cover 17 is formed in a cylindrical shape that is bent in a curved shape and has a horizontal axis, and a horizontal axis is provided on the lower end side of the rear surface of the closing cover 22. An insertion member 33 made of a pipe, a rod or the like having a center is fixed, and this insertion member 33 protrudes inward in the left-right direction from the closing cover 22, and the protruding portion is a cylindrical portion 34 at the lower end of the main portion 21. Is removably inserted.
Further, the upper side of the closing cover 22 is detachably attached to the main portion 21 by a detachable fitting 35, and the closing cover 22 is removed when attaching the agricultural implement to the rotary tiller 1.

The rear cover 17 is of a type without the closing cover 22 (the closing cover 22 is integrally formed with the main portion 21), and the main leveling portion 24 and the extended leveling portion 23 at the lower end side of the main portion 21. Or the like of a type in which a leveling cover provided with can be detachably attached.
Next, the mounting structure of the extended leveling portion 23 will be described in detail.
As shown in FIGS. 1 to 5, a fixing bracket 36 is fixed to the outer side of the back surface of the closing cover 22 in the left-right direction.

The fixing bracket 36 is formed by bending a plate material, and has a bottom wall 36a fixed to the back side of the closing cover 22 and a pair of support walls 36b extending rearward from the upper and lower edges of the bottom wall 36a. The pair of support walls 36b are arranged opposite to each other while their plate surfaces are along the left-right direction.
The fixed bracket 36 is provided with a rotating support shaft 37 having an axis center in a direction orthogonal to the plate surface of the support wall 36 b over the upper and lower support walls 36 b, and the swing bracket 38 is provided via the rotation support shaft 37. The fixed bracket 36 is supported so as to be rotatable about the axis of the rotation support shaft 37.

By fixing the extended leveling portion 23 to the swing bracket 38, the extended leveling portion 23 is supported by the closing cover 22 (main leveling portion 24) so as to be rotatable about the axis of the rotation support shaft 37. By rotating the extended leveling portion 23 around the axis of the support shaft 37, the extended leveling portion 23 can be changed in posture between an extended posture B and a retracted posture C.
The swing bracket 38 is formed by bending a plate material, and has a pair of upper and lower arm portions 38 a located on the opposite side of each support wall 36 b of the fixed bracket 36, and the upper and lower arm portions 38 a support the fixed bracket 36. The wall 36b is bent so as to extend outward in the left-right direction and then to the extended leveling portion 23.

Further, the swing bracket 38 has a fixed wall 38b that is fixed to the inner side in the left-right direction on the back surface of the extended leveling portion 23 and that connects the upper and lower arm portions 38a.
Between the arm portions 38a of the swing bracket 38, there is provided a rotation shaft 39 that is externally fitted around the rotation support shaft 37 so as to be rotatable about the axis. A pressing member 40 made of a plate material having a plate surface perpendicular to the axis of the rotation shaft 39 is fixed to the intermediate portion.
The pressing member 40 has a pressing portion 40 a that comes into contact with the fixed wall 38 b of the swing bracket 38, and the pressing member 40 is operated to rotate around the axis of the rotation support shaft 37. As a result, the extended leveling portion 23 is pressed via the swing bracket 38 and the extended leveling portion 23 is changed from the extended posture B to the retracted posture C.

Further, on the one side (upper side) in the rotational axis direction of the pushing member 40, a retreat operation for biasing the pushing member 40 so as to turn the extended leveling portion 23 from the extended posture B to the retracted posture C side. A spring (retraction operation biasing means) 41 is arranged.
The retraction operation spring 41 is formed of a torsion coil spring and is fitted on the rotation shaft 39, and one end is hooked on the pushing member 40 and the other end is hooked on the support wall 36 b of the fixed bracket 36.
In addition, a connecting member 42 provided on one end side of the inner wire 28 of the operation wire 27 is pivotally connected to a pin 46 provided on the pressing member 40.

The pushing member 40 is rotated by the retracting operation spring 41 when the extended leveling portion 23 is in the retracted posture C, and is rotated by the inner wire 28 when the extended leveling portion 23 is in the extended posture B. It is configured to be.
Further, a wire guide 43 for guiding the inner wire 28 is provided on the other side surface (lower side surface) of the pushing member 40 in the rotational axis direction, and most of the wire guide 43 except for both end portions is pivotally supported. It is formed in an arc shape centered on the axis of the shaft 37.
As shown in FIGS. 1 and 3, in the state where the extended leveling portion 23 is in the extended posture B, the wire guide 43 is positioned on the inner side in the left-right direction of the rotation support shaft 37, and one end of the inner wire 28. The side passes between the wire guide 43 and the main leveling portion 24 and is connected to the pushing member 40 between the turning support shaft 37 (the turning fulcrum of the pushing member 40) and the main leveling portion 24. In this state, when the operating lever 26 is swung from the extended operation position E to the retracting operation position D, the pushing member 40 is rotated around the axis of the rotation support shaft 37 by the urging force of the retracting operation spring 41. Accordingly, when the swing bracket 38 is pressed by the pressing portion 40a, the extended leveling portion 23 is changed to the retracted posture C (the extended leveling portion 23 is moved via the swing bracket 38). Appeared to the retracted posture C by being pushed by the pushing member 40 To change operation).

At this time, the inner wire 28 moves around the rotation support shaft 37 while being wound around the wire guide 43 as the pushing member 40 rotates.
In the present embodiment, the extended leveling portion 23 is provided on the removable cover 22 so that the inner wire 28 is divided between one end of the outer wire 29 and one end of the inner wire 28. At the same time, the divided portion is detachably connected by the joint means 44, and when the closing cover 22 is removed, the joint portion can be divided at the connection portion by the joint means 44.

In the present embodiment, in the extended posture B, the restraining spring 45 serving as an extended leveling portion restraining biasing means for biasing the extended leveling portion 23 in the direction of pressing the extended leveling portion 23 against the farm field is It is provided over.
The holding spring 45 is formed of a tension coil spring, and one end side is hooked on the spring hooking portion 47 of the pushing member 40, and the other end side is hooked on a spring hooking member 48 fixed to the extended leveling portion 23.
One end side of the holding spring 45 is hooked between the pressing portion 40a and the rotation support shaft 37, and the extended leveling portion 23 is moved to the pushing member 40 side (the fixed wall 38b of the swing bracket 38 is pushed). The extended leveling portion 23 is biased so as to be pressed against the pressing portion 40a of the member 40.

When the extended leveling section 23 is changed from the retracted position C to the extended position B, the operation lever 26 is swung from the retracted operation position D to the extended operation position E, and the inner wire 28 is pulled. As a result, the pushing member 40 turns in the direction in which the extended leveling portion 23 turns to the extended posture B. At this time, the extended leveling portion 23 is urged by the restraining spring 45 so as to be pressed against the pushing member 40 side. Therefore, the extended leveling portion 23 follows the pushing member 40 and rotates to the extended posture B.
When the extended leveling portion 23 is in the extended posture B and the extended leveling portion 23 is pushed up by an excessive load from the soil, the fixed wall 38b of the swing bracket 38 is separated from the pressing portion 40a and restrained. The extended leveling portion 23 rotates against the biasing force of the spring 45.

  In the conventional mounting structure of the extended leveling portion 23, as shown in FIG. 8, the extended leveling portion 23 is always urged in the direction of rotating to the extended posture B by the urging force of the torsion coil spring 52, and the inner wire One end side of the inner wire 28 is pivotally connected to a wire guide 53 that is rotatable about a rotation support shaft 37 that rotatably supports the extended leveling portion 23, and one end side of the inner wire 28 is pivotally supported. When the inner wire 28 is pulled when the pin 46 is in contact with the swing bracket 38 and the extended leveling portion 23 is in the extended posture B, the pin 46 pivotally supports one end side of the inner wire 28. The swing bracket 38 is pressed, and the extended leveling portion 23 is configured to rotate around the rotation support shaft 37 from the extended posture B to the retracted posture C against the urging force of the torsion coil spring 52. Leveling The urging force of the torsion coil spring 52 that urges the extended leveling portion 23 gradually increases as the shaft 23 is rotated from the extended posture B to the retracted posture C, and the extended leveling portion 23 is switched between the extended posture B and the retracted posture C. Operating force (in this case, the operating force for changing the posture of the extended leveling section 23 from the extended posture B to the retracted posture C) is large.

  On the other hand, in the present embodiment, the extension leveling unit 23 is rotated from the extended posture B to the retracted posture C side by the urging force of the retracting operation spring 41 and presses the extended leveling unit 23 against the field. Since this is performed by the urging force of the restraining spring 45, the urging force for rotating the extended leveling portion 23 to the retracted posture C is necessary even if the urging force that presses the extended leveling portion 23 against the field is sufficiently large. Since the urging force can be minimized, an operating force for switching the extended leveling portion 23 between the extended posture B and the retracted posture C (in this case, when changing the posture of the extended leveling portion 23 from the retracted posture C to the extended posture B) ) Can be reduced.

  Further, in the conventional one shown in FIG. 8, the extended leveling portion 23 is operated to change the posture from the extended posture B to the retracted posture C by pulling the inner wire 28. One end side of 28 is pivotally connected to the wire guide 53 between the rotation support shaft 37 and the extended leveling portion 23 with the extended leveling portion 23 in the retracted posture C, and the operating force of the inner wire 28 is released. As a result, the extended leveling portion 23 is rotated to the extended posture B around the rotation support shaft 37 by the urging force of the torsion coil spring 52, while the inner wire 28 is wound around the wire guide 53 while the pushing member 40 is moved. It is comprised so that it may move around the rotation spindle 37 with rotation.

In this conventional structure, in order to avoid interference with the extended leveling portion 23, the operation wire 27 is arranged linearly in the vicinity of the mounting portion of the extended leveling portion 23 as shown in FIG. The operation wire 27 must be bent in the vicinity of the outer receptacle 30 that fixes one end of the outer wire 29, and the inner wire with respect to the outer wire 29 at the curved portion of the operation wire 27. There is a problem that the sliding resistance of 28 increases, which increases the operating force.
On the other hand, in the present embodiment, when the extended leveling portion 23 is in the retracted posture C, the extended leveling portion 23 is operated to change the posture from the retracted posture C to the extended posture B by pulling the inner wire 28. One end side of the inner wire 28 is connected to the pushing member 40 between the rotation support shaft 37 and the main leveling portion 24 with the extended leveling portion 23 in the extended posture B, and the inner wire By releasing the operating force of 28, the extended leveling portion 23 is rotated to the retracted posture C by the urging force of the retracting operation spring 41, while the inner wire 28 is wound around the wire guide 53 while the pushing member 40 It is comprised so that it may move around the rotation spindle 37 with rotation.

With this configuration, in this embodiment, as shown in FIG. 3, the operation wire 27 can be arranged in a straight line in the vicinity of the mounting portion of the extended leveling portion 23, and the operation wire 27 can be operated as in the conventional case. An increase in operating force due to the bending of the wire 27 can be prevented.
In addition, in the said conventional thing, the member similar to this embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.
In the embodiment having the above-described configuration, the side drive type rotary tiller 1 is exemplified as the rotary tiller 1, but a center drive type rotary tiller 1 or the like may be employed.

It is sectional drawing which looked at the attachment part of the extended leveling part in an extended attitude | position from the lower side. It is sectional drawing which looked at the attachment part of the extended leveling part in a retracted attitude from the lower side. It is the figure which looked at the left side of the lower end side of a rear cover from the lower side. It is a rear view of the left side of a rear cover. It is a rear view of the attachment part of an extended leveling part. It is a side view of a rotary tiller. It is a disassembled side view of the main part of a rear cover, a closing cover, and an extended leveling part. It is the schematic which shows the attachment structure of the conventional extended leveling part.

Explanation of symbols

23 Extension Leveling Section 24 Main Leveling Section 25 Level Leveling Section 27 Operation Wire 28 Inner Wire 29 Outer Wire 37 Rotating Support Point (Rotating Support Shaft)
40 Pushing member 41 Retraction operation biasing means (retraction operation spring)
45 Energizing means for suppressing the extended leveling part (restraining spring)
B Extended posture C Retracted posture

Claims (2)

  The leveling part (25) for leveling the agricultural field comprises a main leveling part (24) and an extended leveling part (23) extending outward from the main leveling part (24) in the left-right direction, The extended leveling portion (23) is rotatable with respect to the main leveling portion (24), and is rotated to be retracted from the extended posture (B) to the back side of the main leveling portion (24) (C ) And a push member (40) for changing the posture of the extended leveling portion (23) from the extended posture (B) to the retracted posture (C) by being rotated. An urging means (41) for evacuation operation for urging the pushing member (40) so as to rotate (23) from the extended posture (B) to the retracted posture (C), and the pushing member (40). The extended leveling part (23) is provided over the extended leveling part (23), and the extended leveling part (23) is used as a field in the extended posture (B). Working machine, characterized by comprising an extension leveling unit suppressed for urging means for urging (45) in the direction of disciplining.   An operation wire (27) for remotely operating the push member (40) is provided. The operation wire (27) includes an inner wire (28) having one end connected to the push member (40) side, and the inner wire (28). An outer wire (29) for guiding the wire (28) is mainly configured, and the pushing member (40) is operated by pulling the inner wire (28) in a state where the extended leveling portion (23) is in the retracted position (C). ) Is rotated, and the extended leveling member (23) follows the pushing member (40) and rotates to the extended posture (B) by the biasing force of the extended leveling portion restraining biasing means (45). The push wire (40) connecting side of the operation wire (27) is arranged substantially along the main leveling portion (24), and one end side of the inner wire (28) is extended to the extended leveling portion (23). ) In the extended posture Working machine according to claim 1, characterized in that it is connected to the pressing member (40) between the pivot point (37) and the main leveling portion (40) (24).

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