JP7045113B2 - Mower - Google Patents

Description

The present invention relates to an arm-connected agricultural mowing machine that is attached to a three-point link mechanism or the like of a tractor to perform mowing work.

As a prior art of this type of mowing device, "working device for a work vehicle" of Japanese Patent No. 38064665 and "arm-connected mower" of Japanese Patent No. 5512151 are disclosed.

Japanese Patent No. 3806465 states that "the upper part of the second arm (12) is rotatably supported in the vehicle width direction (W) near the tip of the first arm (11), and the second arm (12) is described above. The third arm (13) is rotatably supported in the front-rear direction of the vehicle body (2) at the lower part of the third arm (13), and the working machine (30) is supported at the lower part of the third arm (13) in the vehicle width direction. A work device that rotatably supports the third arm (13) in the vehicle width direction (W), and supports the first arm (11) rotatably. The supporting bracket (10) is supported so as to be horizontally swivel around the pivot pin (14), and the pin (17) is inserted into any of the positioning holes (16) to fix the rotation. It has been disclosed. Further, in Japanese Patent No. 551251, "a second arm pivotally supported at one end in the vehicle width direction of a support member and a second arm rotatably connected to the first arm and having a mower main body attached to the tip thereof. In an arm-connected mower equipped with an arm, an arm-connected mower that can easily switch the mowing machine body between a mowing work state and a retracted state by a lift cylinder, a first link, and a second link "is disclosed. ing.

Japanese Patent No. 38064665 Japanese Patent No. 551251

In the case of an arm-connected mower that is attached to a tractor and used, the work is performed by greatly offsetting the mowing work portion to the side of the tractor. During work, it is not uncommon for the arm connecting the tractor and the mowing work section to inadvertently collide with an obstacle or the like, or for the mowing work section to collide with an obstacle hidden in the grass. When a collision occurs, the impact causes damage to the mower and tractor, which causes problems such as breakdown and damage. In addition, when a collision occurs, the tractor is shaken due to the long arm, causing a fall, deviation from the track, and the like, which poses a safety problem.

The working devices and mowers shown in Patent Document 1 and Patent Document 2 of the prior art have a configuration in which the rotation of the arm during work is fixed and the above-mentioned problems have not been solved.

Therefore, an object of the present invention is to provide an arm-connected mowing machine having a structure in which the tractor and the mowing machine are not easily damaged when the mowing work unit or the arm collides with an obstacle in the arm-connected mowing machine. The purpose is to do.

In order to solve the above problems, the present invention has a main frame provided with a mounting portion on a tractor, a mast frame that can rotate in the front-rear direction with respect to the main frame, and a mast frame having a rotation center at one end. The first boom is provided so that the other end can be rotated up and down, and the second boom is provided so that the other end can be rotated in the left-right direction with one end as the center of rotation on the rotating end side of the first boom. A masting work portion provided so as to be rotatable left and right on the rotation end side of the second boom is provided, and a stopper means for fixing the rotation of the mast frame with respect to the main frame is provided. The stopper means is the mast frame. It is a protective device that is released from fixing and the mast frame becomes rotatable when a certain amount of rotational force acts in the rotation direction of the mast frame, and the stopper means is provided on one end side of the main frame or the mast frame. A movable hook having the other end rotatably provided at the fulcrum and an engaging portion provided at the rotating end of the movable hook to engage with the engaging portion provided on the other side of the main frame or the mast frame. An engaging receiving portion and an elastic member that urges the engaging portion of the movable hook to the engaging receiving portion are provided, and when the rotational force in the rotation direction of the mast frame with respect to the main frame exceeds a certain level, the elastic member is attached. The movable hook rotates against the force to disengage the engaging part and the engaging receiving part, and the mast frame is configured to be released from being fixed in the rotation direction. The mast is provided with a detection means for detecting the rotation, and the masting machine is provided with a control unit for operating the masting work unit by a signal generated by the detecting means detecting the rotation of the movable hook. do.

Further, as a further aspect for solving the above-mentioned problems, the first boom is provided with a changeover valve that enables switching between raising and lowering in a free state, and the changeover valve is provided with a changeover valve changeover switch for switching the changeover valve, and is based on a signal. The gist is that the operation of the mowing work unit is a mowing machine having a configuration that operates only when the changeover valve changeover switch is pressed.

According to the present invention, a first boom and a second boom provided with a grass cutting work portion are provided on the mast frame, and the mast frame can rotate in the front-rear direction with respect to the main frame mounted on the tractor. The rotation is fixed by the stopper means that is released when a certain amount of turning power is applied. Therefore, when the boom or the mowing work part accidentally collides with an obstacle, the stopper means comes off and the mast By rotating the frame backward, it absorbs the impact on the mast to protect the mast and also absorbs the impact on the mounted tractor. In addition, before the fixing of the stopper means is released, if a turning force exceeding the set turning power acts, the mowing work part is raised, so that obstacles to the mowing work part and resistance received from the uneven part field scene are received. Since the reduction is performed before the stopper means comes off, it is not necessary to perform the re-restoration work after the stopper means comes off, and the work can be performed efficiently.

It is a top view of the working state of the mower which carried out this invention. It is a top view of the state where the stopper means of the mower which carried out this invention is removed. It is a rear view of the mower which carried out this invention. It is sectional drawing of the rotation fulcrum part of the mast frame with respect to the main frame. It is explanatory drawing which showed the process which the stopper means of the mower which carried out this invention comes off. It is a side view of the mower which carried out this invention. It is a side view of the mower which carried out this invention. It is a hydraulic circuit diagram of the mower which carried out this invention. It is a perspective view of the operation part of the mower which carried out this invention. It is a flow chart of the mower which carried out this invention.

An embodiment according to an embodiment of the present invention will be described with reference to the drawings.
A is a mower according to an embodiment of the present invention. Reference numeral 1 is an agricultural tractor to which a mower A is attached and driven. In the description of this example, the left side shown in FIG. 1 will be described as the front side in the traveling direction, and the right side will be described as the rear side.

The mower A shown in this example is mounted on a tractor three-point link mechanism 12 provided behind the tractor 1, and is driven and used by power from the tractor 1. 10 is a tractor top link, and 11 and 11 are tractor lower links. Each is provided at the rear of the agricultural tractor 1, and the top link 10 and the lower links 11 and 11 form a three-point link mechanism of the tractor, and the mounted mower A is connected and towed so as to be able to move up and down.

In the mower A of this example, a vertical rotation center shaft 23 is provided near the center of the main frame 2 in which the mounting portion 20 to be mounted on the tractor 1 is provided in front, and the rotation center shaft 23 is used as a center in the front-rear direction. A mast frame 22 is provided so as to be rotatable, an arm portion 3 is provided on the mast frame 22, and a mowing work portion 4 is provided at the tip end portion of the arm portion 3. The arm portion 3 has a first boom 30 having one end rotatably provided on the mast frame 22 in a direction orthogonal to the traveling direction, and a first boom 30 having one end rotatably connected to the rotating end side of the first boom 30. It is composed of two booms 32, and the masting work unit 4 is positioned on the side of the tractor 1 to perform masting work.

The main frame 2 is connected to the rear part of the agricultural tractor 1, and the hydraulic oil tank 50 is mounted on one end of the mower A in the vehicle width direction. 22 located on the other end side is a mast frame. The mast frame 22 is rotatably held on one end side at the left and right central portions of the main frame 2 by a vertical rotation center shaft 23, and in this embodiment, as shown in FIG. 1, the mower A It is located at the left end of the rear view. Reference numeral 300 is a lift cylinder. The base of the lift cylinder 300 is rotatably attached to the mast frame 22 by the lift cylinder shaft 301. The tip end side of the lift cylinder 300 is connected to the tip end side of the first boom 30. The tip of the lift cylinder 300 is connected by a lift cylinder tip shaft 302.

When the lift cylinder 300 is expanded and contracted, the first boom 30 rotates up and down about the first boom rotation shaft 303 on the mast frame 22 side.

In this example, the second boom 32 is connected to the first boom 30 and is connected to a lateral rotation arm 320 that rotates in the left-right direction in the traveling direction, and one end is connected to the lateral rotation arm 320 in the front-rear direction in the traveling direction. The mowing work unit 4 is composed of a rotating front-rear rotation arm 321 and is connected to the rotation end side of the front-rear direction rotation arm 321 so as to be rotatable in the front-rear direction via a mowing work unit holding arm 326. Is provided. By rotating the forward / backward rotation arm 321, the mowing work unit 4 can be moved back and forth with respect to the tractor 1.

The side rotation arm 320 and the end of the first boom 30 are connected by a second boom rotation shaft 324 provided in the front-rear direction. The side rotation arm 320 rotates in the vertical direction, that is, in the vehicle width direction with the second boom rotation shaft 324 as the rotation center in response to the expansion and contraction of the second boom rotation cylinder 322.
The base of the second boom rotating cylinder 322 is attached closer to the mast frame 22 of the first boom 30. The tip of the second boom rotation cylinder 322 is the tip shaft of the second boom rotation cylinder provided at a position extending toward the first boom 30 side from the second boom rotation shaft 324 of the side rotation arm 320. It is linked to 327. The first boom 30 and the lateral rotation arm 320 are each rotatable in the vertical direction.

The front-back rotating arm 321 is made of a hollow cylindrical metal square pipe. Reference numeral 323 is a second boom front-rear rotation cylinder. The base of the second boom anteroposterior rotation cylinder 323 is attached to the side rotation arm 320. The tip of the second boom anteroposterior rotation cylinder 323 is attached to a substantially central portion of the anteroposterior rotation arm 321. The front-rear rotation arm 321 is rotatable in the front-rear direction, that is, in the traveling direction or the backward direction with respect to the lateral rotation arm 320.

The lateral rotation arm 320 rotates the front-rear direction rotation arm 321 with respect to the first boom 30 in the vertical direction and the front-rear direction so as to rotate in the vertical direction and the front-rear direction in which the rotation directions differ by 90 degrees. It is connected to the moving arm 321. The front-rear rotation arm 321 connects the mowing work unit 4 to the tip thereof via the mowing work unit holding arm 326 connected to one end opposite to the side rotation arm 320. The front-back rotation arm 321 responds to the expansion and contraction of the second boom rotation cylinder 322 and the second boom front-back rotation cylinder 323, and the front-back rotation arm 321 is a rotation fulcrum provided on the second boom rotation shaft 324 and the side rotation arm 320. It rotates about the shaft 325 in the vertical direction and the front-rear direction, that is, in the vehicle width direction and the traveling direction or the backward direction.

The front-rear direction rotation arm 321 connects the front-back rotation arm 321 and the mowing work part 4 via the mowing work part holding arm 326. The front-rear direction rotation arm 321 and the mowing work portion holding arm 326 are rotatable about the rotation center 328 in the front-rear direction, that is, in the traveling direction or the backward direction.

Reference numeral 334 is a mowing work section rotating cylinder. The mowing work unit rotation cylinder 334 rotates the mowing work unit 4 in the vertical direction with respect to the mowing work unit holding arm 326 with the mowing work unit rotation shaft 337 in the front-rear direction as the rotation center.

Reference numeral 33 is a mowing work section link mechanism. The mowing work section link mechanism 33 has a first link arm 330 whose one end is rotatably connected to the mowing work section holding arm 326 side and a second link whose one end is rotatably connected to the mowing work section 4 side. The arm 331 is rotatably connected to the second link arm 331, and the mowing work section rotation cylinder 334 is rotatably connected to the second link arm 331 and the mowing work section holding arm 326 side.

The first link arm 330 has a semi-circular ring shape, the second link arm 331 also has a semi-circular ring shape as a whole, and the first link arm 330 and the second link arm 331 are connected by a mounting shaft 332. Will be done. The first link arm 330 is connected to the mowing work portion holding arm 326 by the mounting shaft 333. The second link arm 331 and the mowing work unit 4 are connected to the mowing work unit 4 by a mounting shaft 335. The mowing work unit 4 is rotatably connected with the rotation shaft 337 of the mowing work unit in the front-rear direction as the center of rotation. Therefore, the mowing work unit 4 is rotatable in the vertical direction with respect to the mowing work unit holding arm 326.

The second link arm 331 and the mowing work section rotating cylinder 334 are mounted at a position farther from the mounting shaft 335 on the mowing work section 4 side than the connecting shaft 332 of the first link arm 330 and the second link arm 331. It is rotatably connected by a shaft 336. The first link arm 330 and the second link arm 331 are formed in a substantially circular ring shape. Therefore, the amount of movement is large, and it is possible to increase the amount of rotation as a whole.

A rod (not shown) for rotatably connecting the lateral rotation arm 320 and the mowing work portion holding arm 326 is provided in the hollow cylindrical metal square pipe of the front-rear rotation arm 321. A parallel link is formed with the front-rear rotation arm 321. Therefore, even when the front-rear rotation arm 321 rotates in the front-rear direction, the mowing work portion holding arm 326 is configured to maintain a state orthogonal to the traveling direction. Therefore, the mowing work unit 4 also maintains an orthogonal state.

The mowing work unit 4 is attached to the mowing work unit rotation axis 40 in a direction orthogonal to the traveling direction by projecting a large number of mowing blades 41. A protective cover is provided above the mowing work unit 4 to prevent scattering from the rotating mowing blade 41. Reference numeral 42 denotes a gauge roller, which is located behind the rotation shaft 40 of the mowing work portion and has a horizontal rotation axis, and is in contact with the field scene during work to stabilize the mowing height. 43 is a hydraulic motor. The hydraulic motor 43 is rotated by the hydraulic pressure generated by the hydraulic pump 51 to rotationally drive the mowing work unit rotary shaft 40 to which the mowing blade 41 is attached.

Each hydraulic pressure actuating portion of the mower A is provided in the center of the front portion of the main frame 2 and is actuated by the hydraulic pressure generated from the hydraulic pump 51 which is rotationally driven by the power from the tractor 1. The power from the tractor 1 is input by connecting the input shaft 21 provided so as to project in front of the hydraulic pump 51 and the PTO shaft (not shown) of the tractor 1 with a universal joint or the like. A hydraulic oil tank 50 is provided on the right side of the main frame 2 as shown in FIG. 3, and oil used by being piped to each hydraulic fluid operating unit is stored. Further, a hydraulic operation valve (not shown) for switching the piping to each hydraulically actuated portion is provided in the cover of the central side side portion of the hydraulic oil tank 50. As the hydraulic operation valve, an electric valve that operates electrically is adopted, and is operated by an electric operation lever 7 provided in the vicinity of the driver's seat in the tractor 1. Each hydraulically actuated part is piped with a hydraulic hose or the like (not shown).

FIG. 8 is a hydraulic circuit diagram of the mower A of the present invention. The hydraulic pump 51, which is a source of hydraulic pressure, is rotated by power from the tractor 1 to generate hydraulic pressure. In this example, the hydraulic pump 51 is divided into two systems, a hydraulic system for rotating the mowing work unit 4 and a hydraulic system for operating each hydraulic cylinder. The hydraulic motor 43 for rotating the mowing work unit 4 is piped from the hydraulic pump 51 through the mowing blade rotation operation valve 524. The mowing blade rotation operation valve 524 is an electrically operated solenoid valve, and is provided with a port for switching the rotation direction of the hydraulic motor 43 in the forward and reverse directions and a neutral port. In the neutral state, the forward / reverse rotation circuit of the hydraulic motor 43 and the drain circuit leading to the hydraulic oil tank 50 are in communication with each other to prevent reverse hydraulic pressure generation due to inertial rotation from the hydraulic motor 43 at the time of forward / reverse rotation switching or stop operation. do. Further, a relief valve 54 is provided in the circuit on the pressurizing side so that when the pressure inside the circuit exceeds a certain level, oil escapes to the hydraulic oil tank 50 and the pressure does not rise above a certain level. ..

In the hydraulic system for operating each hydraulic cylinder, a hydraulic operation valve 52 is provided between the hydraulic pump 51 and each cylinder, and the expansion / contraction operation of each cylinder is switched and operated. The hydraulic operation valve 52 is integrally provided with a lift cylinder operation valve 520, a second boom rotation cylinder operation valve 521, a second boom front-rear direction rotation cylinder operation valve 522, and a mowing work section rotation cylinder operation valve 523. ing. A relief valve 54 is provided in the pressurizing side circuit of each operation valve so that oil does not escape to the hydraulic oil tank 50 and the pressure does not rise above a certain level when the pressure inside the circuit exceeds a certain level. It has become. Each valve is an electrically operated solenoid valve and is electrically operated by an operating lever 7 provided near the driver's seat of the tractor 1.

The lift cylinder operation valve 520 is a valve for operating the expansion and contraction of the lift cylinder 300 that raises and lowers the first boom 30. A switching valve 53 is provided between the port on the side that lifts the first boom 30 of the lift cylinder 300 and the lift cylinder operation valve 520. The switching valve 53 has a check valve 530 side in which the direction in which the first boom 30 descends is blocked and the ascending direction is in a free state, and a side in which the circuit is released and the first boom 30 is in a free state. Can be switched to.

When the lift cylinder operation valve 520 is switched in the direction of lifting the first boom 30 with the switching valve 53 switched to the check valve 530 side, the oil passes through the check valve 530 of the switching valve 53 and this example of the lift cylinder 300. Flows to the shrinking port in, and oil from the other port flows to the circuit on the return side to the hydraulic oil tank 50. When the lift cylinder operation valve 520 is switched in the direction of lowering the first boom 30, the switching valve 53 switches to the released side of the circuit. The switching is electrically controlled and is set to automatically switch when the lift cylinder operation valve 520 is switched. Therefore, the oil flows into the port in the extending direction of the lift cylinder 300 in this example, and the oil flows from the other port to the circuit on the return side to the hydraulic oil tank 50 via the switching valve 53.

When the lift cylinder operation valve 520 is in the neutral state, the circuit in the direction in which the first boom 30 descends, that is, in the direction in which the lift cylinder 300 in this example extends is blocked by the check valve 530 of the switching valve 53, and the first The descent of the boom 30 is locked. At this time, when an external force acts in the direction of raising the first boom 30, the check valve 530 opens and the first boom 30 can freely move in the ascending direction. Therefore, when the mowing work portion 4 is carelessly lifted by an obstacle or the like, the mowing machine A is protected by preventing an excessive load from acting on the arm portion 3.

Further, when the lift cylinder operation valve 520 is set to the neutral state and the switching valve 53 is switched to the side where the circuit is released while the mowing work unit 4 is in contact with the field scene during the mowing work, the first boom 30 is raised and lowered. Since it is in a free state, the mowing work unit 4 can automatically follow the unevenness of the mowing field scene by the weight of the mowing work unit 4 to keep the mowing height constant. Therefore, the operator does not need to frequently operate the operation lever 7 according to the unevenness of the cutting field scene, so that the work can be easily performed. To switch the switching valve 53 to the side where the circuit is released, the switching valve switching switch 72 of the operation lever 7 provided near the driver's seat of the tractor 1 is pressed. The changeover valve changeover switch 72 is switched only when it is pressed. A pressure sensor 55 is provided in the circuit of the port on the side where the first boom 30 of the lift cylinder 300 rises, and is electrically controlled so that the switching valve 53 can be switched only when the pressure is equal to or lower than the set pressure. ing. Therefore, when pressure is applied to the lift cylinder 300 while the mowing work unit 4 is raised from the field scene, the switching valve 53 cannot be switched, so that the mowing work unit 4 is not inadvertently dropped and is safe. It is possible to carry out the work and prevent damage to the mowing work unit 4.

The second boom rotating cylinder operating valve 521, the second boom forward / backward rotating cylinder operating valve 522, and the mowing work section rotating cylinder operating valve 523 have the same circuit configuration, respectively, and the second boom rotating cylinder 322. , The second boom forward / backward rotation cylinder 323 and the mowing work section rotation cylinder 334 are respectively piped. In the neutral state, the circuit of each operation valve is closed so that the expansion and contraction of each cylinder is prevented. When each operation valve is switched in the expansion / contraction direction, each cylinder expands and contracts to move the arm portion 3 to operate the tilted posture and position of the mowing work portion 4.

The operation of each operation valve is electrically operated by the operation lever 7 installed near the driver's seat of the tractor 1. FIG. 9 shows the operating lever 7. In this example, it is installed on the left side of the driver's seat, and in FIG. 9, the right side is the front side. The operating lever 7 has a rod-shaped grip that can be gripped with one hand, and operates each cylinder by tilting it back and forth and left and right. The operation lever 7 is provided above the rectangular box, and a rotation direction changeover switch 70 for switching the rotation direction of the mowing work portion 4 is provided in the front portion. When the rotation direction changeover switch 70 is tilted in the front-rear direction, the rotation direction of the mowing work portion 4 is changed, and when it is positioned at the center portion, the hydraulic circuit becomes free and the rotation stops. A control unit for operating each operation valve by a signal from the operation lever 7 is built in the rectangular box.

A cylinder changeover switch 71 and a changeover valve changeover switch 72 are provided on the upper surface of the operation lever 7 side by side. Each switch is a switch that operates only when it is pressed, and is operated with the thumb while holding the operation lever 7. By pressing the changeover valve changeover switch 72, the changeover valve 53 can be switched to the side where the circuit is released. In this example, when the operating lever 7 is tilted forward in FIG. 9, the lift cylinder 300 expands to rotate the first boom 30 downward, and when tilted backward, the lift cylinder 300 contracts and the first boom 30 moves upward. Rotate. When tilted to the left, the second boom rotating cylinder 322 contracts and the second boom 32 rotates laterally outward, and when tilted to the right, the second boom rotating cylinder 322 expands and the second boom 32 laterally. Rotate inward. Further, when the cylinder changeover switch 71 is pushed and tilted to the left, the mowing work section rotating cylinder 334 expands and the mowing working section 4 is rotated downward, and when tilted to the right, the mowing working section rotating cylinder 334 contracts. The mowing work unit 4 is rotated upward. Furthermore, when the operation lever 7 is tilted forward while pressing the cylinder changeover switch 71, the second boom front-rear rotation cylinder 323 is extended and the front-rear rotation arm 321 of the second boom 32 is rotated forward and rearward. When tilted to, the second boom front-rear rotation cylinder 323 contracts, and the front-rear rotation arm 321 of the second boom 32 rotates backward.

A mast frame 22 provided with a rotation center shaft 23 in the vertical direction near the center of the main frame 2 and rotatably provided in the front-rear direction around the center is a stopper means provided on the rotation end side of the mast frame 22. 6 is locked to the main frame 2 to prevent rotation. The stopper means 6 is configured to be released from locking when a certain amount of rotational force acts in the rotation direction of the mast frame 22.

FIG. 5 is a cross-sectional view of a main part for explaining the stopper means 6 of this example. (A) shows a state in which the stopper means 6 is locked to the main frame 2 side to prevent rotation with the mast frame 22, and (b) shows a state immediately before the stopper means 6 is released. , (C) show a state in which the stopper means is disengaged. The stopper means 6 includes a movable hook 60 that is bridged and engaged with the main frame 2 and the mast frame 22, a fulcrum pin 62 fixed to the mast frame 22 that is a rotation fulcrum of the movable hook 60, and a movable hook 60. The spring 61 that presses the spring 61, the support shaft 63 that guides the spring 61 and the movable hook 60, the nut 64 that is screwed to the end of the support shaft 63 to adjust the pressing force of the spring 61, and the rotation of the movable hook 60. It is composed of a limit switch 66 which is a detection means for detecting.

The support shaft 63 is vertically erected and fixed to the mast frame 22. A guide hole 600 for inserting into the support shaft 63 is provided near the center of the movable hook 60, and a holding hole 601 for inserting into the support pin 62 fixed to the mast frame 22 is provided on one end side. ing. The movable hook 60 inserted into the support shaft 63 is further pressed downward by the spring 61 inserted into the support shaft 63. A nut 64 is screwed into the upper end of the support shaft 63 so that the pressing force can be adjusted.

The end portion of the movable hook 60 opposite to the holding hole 601 is cantilevered on the main frame 2 side, and the end portion is provided with an engaging portion 602 projecting downward in a mountain shape. Has been done. Further, on the main frame 2 side facing the engaging portion 602, an engaging receiving portion 65 that also protrudes in a mountain shape toward the movable hook 60 side is fixedly provided, and the slopes of both protruding portions overlap each other. (A). The slopes of the projecting portions in the direction of preventing horizontal rotation are opposed to each other, and the rotation of the main frame 2 and the mast frame 22 is prevented. The projecting portion of the movable hook 60 is pushed up along the slope by the component force of the horizontal turning force against the pressing force of the movable hook 60 (b), and when the projecting portions are disengaged, the mast frame 22 rotates. Becomes free. The movable hook 60 does not necessarily have to be provided on the mast frame 22 side, and may be provided on the main frame 2 side. When the movable hook 60 is pushed up and rotated along the inclined surface of the engaging receiving portion 65 against the pushing pressure of the movable hook 60, the arm of the limit switch 66, which is a detection means in contact with the lower surface, rotates. Then the switch is activated and a signal is sent to the control unit.

When a signal is sent to the control unit, the lift cylinder 300 contracts to raise the mowing work unit 4 until the movable hook 60 is disengaged, and acts to release the resistance acting on the mowing work unit 4. do. The resistance acting on the mowing work unit 4 includes, for example, the resistance when colliding with a protrusion as shown in FIG. 6 and the resistance due to a sharp convex portion as shown in FIG. 7, and the mowing work unit 4 rises. When the resistance is released, the arm of the return limit switch 66 is pushed before the movable hook 60 is disengaged to stop the operation of the lift cylinder 300. When a turning force larger than the holding force of the stopper means 6 acts, the movable hook 60 is disengaged and the state shown in FIG. 5 (c) is reached, the movable hook 60 pushes the arm of the limit switch 66, and the mast frame 22 is moved. It will be in a state of rotating backward.

In the case of this example, the control in which the control unit contracts the lift cylinder 300 and raises the mowing work unit 4 by the operation of the limit switch 66 is controlled so as to operate only when the changeover valve changeover switch 72 is pressed. .. FIG. 10 is a control flow diagram. When the changeover valve changeover switch 72 is pressed (a1) and the mowing work is performed, the limit switch 66, which is a movable hook sensor that detects the rotation of the movable hook 60 of the stopper means 6, becomes detectable. When the movable hook 60 rotates due to the resistance acting on the working part, the limit switch 66 is turned on (a2), the changeover valve changeover switch 72 is turned off (a3), and the lift cylinder 300 shrinks to move the mowing work part 4. Raise it (a4). When the mowing work unit 4 rises and the resistance in the rotation direction decreases, the movable hook 60 returns, and the limit switch 66 is pressed to turn it off (a5). When it is turned off, the operation of the lift cylinder 300 is stopped (a6). When a turning force larger than the engagement holding force of the stopper means 6 is applied, the limit switch 66 is turned on, the changeover valve changeover switch 72 is turned off (a3) as the movable hook 60 rotates, and the lift cylinder 300 is turned on. However, when the movable hook 60 is disengaged, the limit switch 66 is pushed again by the movable hook 60 to turn off, and the lift cylinder 300 also stops. In the case of this example, the mowing work unit 4 is controlled to be raised to release the resistance only when the changeover valve changeover switch 72 is pressed, but even if it is controlled so that it can be operated in any working state. good.

Due to this configuration, when the arm portion 3 or the mowing work portion 4 provided on the mast frame 22 collides with an obstacle or the like due to the advance of the tractor 1, the engaging portion 602 of the movable hook 60 engages with the engaging receiving portion 65. The mast frame 22 is freed to rotate in the front-rear direction, and rotates backward together with the arm portion 3 and the mast working portion 4 to absorb the impact and avoid damage to the mast frame A. FIG. 2 is a plan view showing a state of being rotated backward. To return from the rotated state to the mowing work state, when the tractor 1 is retracted with the mowing work unit 4 in contact with the ground, the mast frame 22 rotates forward and the engaging portion of the movable hook 60. The 602 and the engagement receiving portion 65 on the main frame 2 side are engaged with each other to fix the rotation.

FIG. 4 is a side view showing a cross section of a main part of the rotation center shaft 23 of the mast frame 22. A mounting portion 20 for connecting to the tractor 1 is provided in front of the main frame 2, and a rotation center shaft 23 for rotating the mast frame 22 with respect to the main frame 2 is vertically concentric with the rear portion thereof. There are two places. The mounting portion 20 is a three-point link on the tractor 1 side to a top pin 202 in the left-right horizontal direction located in the upper center portion provided on the front side of the main frame 2 and a lower pin 203 in the left-right horizontal direction provided on the lower left and right thereof. The quick hitch 13 attached by the top link pin 200 and the lower link pin 201 is engaged with the mechanism 12 and attached to the tractor 1. The quick hitch 13 is provided with a hook portion that engages with the top pin 202 at the upper center portion, and hook portions that engage with the lower pin 203 are provided on the lower left and right sides, and the hook portion is engaged and connected.

The rotation center shaft 23 of the mast frame 22 is located behind the left and right center portions of the mounting portion 20 to which the quick hitch 13 is connected. That is, it is located on the left and right center lines of the tractor 1. Therefore, when the arm portion 3 or the mast cutting work portion 4 collides with an obstacle or the like due to the advancement of the tractor 1 and the mast frame 22 rotates, the reaction force eccentric to the tractor 1 is unlikely to act. Further, it is easy to operate the tractor 1 when the tractor 1 is retracted in order to restore the mast frame 22 that has been rotated rearward.

Next, a case where the mowing work is performed using the mowing machine A of the present invention will be described. A quick hitch 13 is attached to a tractor 3-point link mechanism 12 consisting of a pair of left and right lower links 11 provided behind the tractor 1 and a top link 10 provided above the center thereof, and a lower pin provided in front of the main frame 2 of the mower. The hook portion of the quick hitch 13 is engaged with the 203 and the top pin 202 to connect the tractor 1 and the mower. Further, the input shaft 21 of the hydraulic pump 51 provided in the center of the front of the mowing machine and the PTO shaft of the tractor 1 are connected by a universal joint or the like so that the hydraulic pump 51 can be driven.

In the mowing field, the PTO axis of the tractor 1 is rotated to drive the hydraulic pump 51, and the operation lever 7 is operated to operate the arm portion 3 to position the mowing work portion 4 in the mowing field scene. Then, the rotation direction changeover switch 70 provided on the operation lever 7 of the driver's seat of the tractor 1 is operated to drive the mowing work unit 4 to rotate. Then, when the tractor 1 is run, the mowing work is performed. The gauge roller 42 of the mowing work unit 4 abuts and follows the unevenness of the field scene due to its own weight to keep the mowing height constant. When the mast cutting work portion 4 or the arm portion 3 collides with an obstacle or the like, the stopper means 6 is disengaged and the mast frame 22 rotates rearward to alleviate the impact force and protect the mower. In order to return the mast frame 22 that has rotated backward, the mast frame 22 rotates forward and the stopper means 6 engages with the work when the mast frame 22 is grounded and the tractor 1 is retracted at a low speed. It becomes a state. When working by pressing the changeover valve changeover switch 72, in the case of a light rotational load on the mast frame 22, the lift cylinder 300 operates to raise the mowing work section 4 before the stopper means 6 comes off, resulting in an obstacle. Etc. are automatically avoided.

INDUSTRIAL APPLICABILITY The present invention can be used for an arm-connected mowing machine for mowing work, which is used by being mounted behind a traveling machine such as a tractor.

1 tractor 10 top link 11 lower link 12 3-point link mechanism 13 quick hitch 2 main frame 20 mounting part 200 top link pin 201 lower link pin 202 top pin 203 lower pin 21 input shaft 22 mast frame 23 rotation center shaft 3 arm part 30 1st boom 300 Lift cylinder 301 Lift cylinder shaft 302 Lift cylinder tip shaft 303 1st boom rotation shaft 32 2nd boom 320 Side rotation arm 321 Front and rear rotation arm 322 2nd boom rotation cylinder 323 Second boom front and back Directional rotation cylinder 324 2nd boom rotation shaft 325 Rotation fulcrum shaft 326 Mowing work part holding arm 327 2nd boom rotation cylinder tip shaft 328 Rotation fulcrum shaft 33 Mowing work part link mechanism 330 1st link arm 331 2nd Link arm 332 Mounting shaft 333 Mounting shaft 334 Mowing work part Rotating cylinder 335 Mounting shaft 336 Mounting shaft 337 Mowing work part Rotating shaft 4 Mowing work part 40 Mowing work part Rotating shaft 41 Mowing blade 42 Gauge roller 43 Hydraulic motor 50 Hydraulic oil Tank 51 Hydraulic pump 52 Hydraulic operation valve 520 Lift cylinder operation valve 521 Second boom rotation cylinder operation valve 522 Second boom forward / backward rotation cylinder operation valve 523 Mowing work part rotation cylinder operation valve 524 Mowing blade rotation operation valve 53 Switching Valve 530 Check valve 54 Relief valve 55 Pressure sensor 6 Stopper means 60 Movable hook 600 Guide hole 601 Holding hole 602 Engagement part 61 Spring 62 Abutment pin 63 Support shaft 64 Nut 65 Engagement receiving part 66 Limit switch 7 Operation lever 70 Rotation direction Changeover switch 71 Cylinder changeover switch 72 Changeover valve changeover switch

Claims (2)

A main frame with a mounting part for the tractor,
A mast frame that can rotate in the front-rear direction with respect to the main frame,
The mast frame has a first boom provided with one end rotatably centered on the other end and the other end rotatably.
A second boom provided on the rotating end side of the first boom with one end as the center of rotation and the other end rotatably in the left-right direction.
A mowing work unit provided so as to be rotatable left and right on the rotating end side of the second boom is provided.
A stopper means for fixing the rotation of the mast frame with respect to the main frame is provided.
The stopper means is a protective device that is released from fixing and makes the mast frame rotatable when a certain amount of rotational power acts in the rotation direction of the mast frame.
The stopper means includes a movable hook provided on one of the main frame or the mast frame and rotatably provided on the other end with one end side as a fulcrum.
An engaging portion is provided at the rotating end of the movable hook, and an engaging receiving portion that engages with the engaging portion provided on the other side of the main frame or the mast frame.
An elastic member that urges the engaging portion of the movable hook to the engaging receiving portion is provided.
When the rotational force of the mast frame with respect to the main frame exceeds a certain level, the movable hook rotates against the urging force of the elastic member to engage the engaging portion and the engaging receiving portion. It is configured so that the mast frame is released and the mast frame is released from being fixed in the rotation direction, and a detection means for detecting the rotation of the movable hook is provided.
A control unit that operates the mowing work unit by a signal generated by the detection means detecting the rotation of the movable hook, and a control unit.
A mower characterized by being equipped with. The first boom has a switching valve that enables switching between raising and lowering in a free state.
The changeover valve comprises a changeover valve changeover switch for switching the changeover valve.
The operation of the mowing work unit by the signal is configured to operate only when the changeover valve changeover switch is pressed.
A mower characterized by that.

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