Mowing device

Abstract

To provide a mowing machine capable of coping with mowing of a slope by a mowing unit and performing stable mowing by surely operating the mowing unit.SOLUTION: The mower includes a mowing unit 10 rotated by a hydraulic motor 15, a base 20 attached to the front side of a work vehicle W, an arm mechanism 30 having a base end supported by the base 20 and a tip end to which the mowing unit 10 is attached, the arm mechanism 30 changing the position of the mowing unit 10 and changing the angle of a cutter surface 17 of the mowing unit 10 by a hydraulic cylinder device 40, and a hydraulic drive part 60 operating the hydraulic motor 15 and the hydraulic cylinder device 40 based on hydraulic pressure supplied from a discharge port 4 of an external hydraulic supply part of the work vehicle W. The hydraulic driving part 60 is provided with a flow dividing valve 61 which supplies the hydraulic oil from an external hydraulic supply part to the hydraulic motor 15 and the hydraulic cylinder device 40 by dividing the flow, and preferentially supplies a constant flow rate to the hydraulic cylinder device 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a brush cutting device that is attached as one of the implements to the front of a work vehicle such as a skid steer loader or a tractor. [Background technology]

[0002] Generally, work vehicles such as skid steer loaders and tractors are provided with a standard mounting section on the front of the vehicle body for attaching a work tool, and various work tools such as a shovel, bucket, pallet fork, manifold fork, harrow, and ridger can be attached to this standard mounting section, and work is performed using this work tool. Conventionally, brush cutting devices that can be attached to these work vehicles as one of the work tools have been known.

[0003] A conventional brush cutting device of this type is known, for example, from Utility Model Registration No. 3101099 (Patent Document 1). This brush cutting device is attached to, for example, a skid steer loader as a work vehicle. This work vehicle is provided with a specified attachment part for attaching a working tool to the front of the vehicle body while it is traveling. The brush cutting device is equipped with a hydraulically driven brush cutting unit with an exposed cutter face that faces the ground and rotates to cut grass, and this brush cutting unit is attached to the work vehicle and hydraulic piping is connected to an external hydraulic supply unit provided on the work vehicle so that brush cutting can be carried out.

[0004] However, with this conventional brush mowing device, the mowing unit is attached to the front of the work vehicle's body, so it is effective on ground on which the work vehicle can travel, but there is a problem in that it cannot be used to mow roadsides where the work vehicle cannot travel, particularly on slopes that slope upward or downward. In work vehicles such as power shovels and backhoes, where the standard attachment part of the work implement is attached to a freely movable arm, the angle and position of the mowing unit can be freely changed, so there is a degree of freedom and it is possible to mow on such slopes, but it is not suitable for work vehicles such as skid steer loaders and tractors, where the standard attachment part is on the front of the body and there is little freedom in changing the position of this standard attachment part.

[0005] To solve this problem, conventionally, mowing devices have been proposed that are equipped with arm mechanisms similar to those used in power shovels, backhoes, etc. The arm mechanisms and mowing units are operated using hydraulic pressure used in work vehicles (see, for example, Japanese Utility Model Application Laid-Open Publication No. 5-23805). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Utility Model Registration No. 3101099 [Patent Document 2] Japanese Utility Model Application Publication No. 5-23805 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, in the above-mentioned conventional mowing device equipped with an arm mechanism, by operating the arm mechanism it is possible to mow on slopes, but because the hydraulic pressure from the work vehicle is used not only to operate the mowing unit but also to operate the arm mechanism, there is a problem that when both are operated simultaneously, if the necessary and sufficient amount of pressurized oil does not reach the arm mechanism, which is subjected to more force than the mowing unit, the mowing unit may not be positioned properly and sufficient mowing may not be performed.

[0008] The present invention has been made in consideration of the above problems, and aims to provide a grass cutting device that can cut grass on slopes using the grass cutting unit and can reliably operate the arm mechanism to perform stable grass cutting. [Means for solving the problem]

[0009] In order to achieve the above object, the brush cutting device of the present invention is attached to the front of a traveling work vehicle as one of the implements and is driven by hydraulic pressure supplied from an external hydraulic pressure supply unit provided on the work vehicle, the work vehicle includes a grass cutting unit having a cutter surface on which a cutter that faces the ground and is rotated by a hydraulic motor to cut grass is exposed; a base that is attached to the front of the work vehicle; an arm mechanism having a base end supported by the base and a tip end to which the grass cutting unit is attached, and having a hydraulic cylinder device that changes the position of the grass cutting unit relative to the work vehicle and changes the angle of the cutter surface of the grass cutting unit; and a hydraulic drive unit that is mounted on the base and operates the hydraulic motor of the grass cutting unit and the hydraulic cylinder device of the arm mechanism based on hydraulic pressure supplied from the external hydraulic supply unit, The hydraulic drive unit is configured to include a flow dividing valve that divides the hydraulic oil supplied from the external hydraulic supply unit and supplies it to the hydraulic motor and hydraulic cylinder device, and preferentially supplies a constant flow rate to the arm mechanism.

[0010] It is effective to use a variable flow rate dividing valve for this purpose. This allows hydraulic oil to be supplied in accordance with the capacities of the hydraulic motor and hydraulic cylinder device, resulting in a good balance. This type of dividing valve is configured, for example, with an inlet port for hydraulic oil from an external hydraulic supply unit, one outlet port to the hydraulic motor side, and the other outlet port to the hydraulic cylinder device side, and is equipped with a pressure compensating spool variable throttle valve and a relief valve inside. Even if there are pressure fluctuations on the inlet port, one outlet port, and other outlet port side, a constant flow rate can be preferentially flowed to the other outlet port, and the surplus flow rate can be flowed to the one outlet port.

[0011] When using this brush cutting device, first, the base is attached to the front of the work vehicle, and the necessary hydraulic piping is installed to the hydraulic drive unit mounted on the base so that hydraulic pressure is supplied from the work vehicle's external hydraulic supply unit. The necessary hydraulic piping can be installed in advance from the hydraulic drive unit to the hydraulic motor of the brush cutting unit and the hydraulic cylinder device of the arm mechanism via a diverter valve. In this state, the arm mechanism is operated by the hydraulic cylinder device of the arm mechanism, and the position of the brush cutting unit relative to the work vehicle and the angle of the cutter face of the brush cutting unit are set according to the work conditions. The hydraulic motor of the brush cutting unit is then driven to cut grass with the brush cutting unit while the work vehicle is traveling as appropriate. In this case, the cutter face of the brush cutting unit can be adjusted to fit the slope, making it possible to cut grass on such slopes, improving versatility.

[0012] In this case, hydraulic pressure is supplied from the work vehicle's external hydraulic supply unit to the hydraulic motor and hydraulic cylinder device through a diverter valve, but even when both the hydraulic motor and the hydraulic cylinder device are operated simultaneously, the diverter valve is a priority type diverter valve that preferentially flows a constant flow rate to the hydraulic cylinder device side, so a necessary and sufficient amount of pressurized oil reaches the arm mechanism, which is subjected to more force than the grass cutting unit, and this prevents a situation where the grass cutting unit is not positioned properly and grass is not cut properly, ensuring reliable grass cutting. Also, because both the hydraulic motor and the hydraulic cylinder device can be operated using a single external hydraulic supply unit of the work vehicle, there is no need to provide a separate hydraulic supply unit dedicated to the hydraulic cylinder device or a hydraulic supply unit dedicated to the hydraulic motor on the work vehicle, which improves piping efficiency and versatility.

[0013] If necessary, the arm mechanism is configured to include a first arm having a base end supported on the base so as to be rotatable around a first rotation axis, and a second arm having a base end supported on the tip end of the first arm so as to be rotatable around a second rotation axis, and having one end of the grass cutting unit attached to the tip end so as to be rotatable around a third rotation axis, The hydraulic cylinder device of the arm mechanism is configured to include a first hydraulic cylinder that is provided between the base and the first arm and changes the angle therebetween, a second hydraulic cylinder that is provided between the first arm and the second arm and changes the angle therebetween, and a third hydraulic cylinder that is provided between the second arm and the mowing unit and changes the angle therebetween, The hydraulic drive unit is provided with a first solenoid valve, a second solenoid valve and a third solenoid valve, which are provided corresponding to the first hydraulic cylinder, the second hydraulic cylinder and the third hydraulic cylinder, respectively, and which selectively supply the hydraulic oil supplied from the flow dividing valve to each of the hydraulic cylinders. This makes it easier to control the hydraulic motor and the hydraulic cylinder device.

[0014] In this case, it is effective to provide the first, second and third rotating shafts with their axes aligned along the longitudinal direction of the work vehicle, and to operate the brush cutting unit on the side of the work vehicle in the direction of travel. This results in a brush cutting device that is exclusively used on the side of the work vehicle, but this simplifies the structure.

[0015] Furthermore, in this configuration, it is effective to provide the base with mounting bodies on one and the other of the front and rear sides of the work vehicle, respectively, for detachably mounting to the front of the work vehicle. As a result, by selecting either the mounting body on one or the other of the front and rear sides and attaching the base to the work vehicle, it becomes possible to selectively position the arm mechanism and brush cutting unit on either the left or right side of the work vehicle depending on the brush cutting conditions, thereby improving versatility.

[0016] In addition, if necessary, the system may include a fixed link having one end fixed to the grass cutting unit and the other end rotatably supported relative to the third rotating shaft, a first movable link having one end at the tip of the second arm and rotatably provided around the first rotating shaft near the base end side of the third rotating shaft, and a second movable link having one end rotatably provided around the second rotating shaft on one end side of the fixed link and the other end rotatably provided around the third rotating shaft at the other end of the first movable link, wherein one end of the third hydraulic cylinder is rotatably provided on a fourth rotating shaft between the third rotating shaft of the first movable link and the third rotating shaft so as to be linked to the fourth rotating shaft, and the forward and backward movement of the third hydraulic cylinder is transmitted to the fixed link via the first movable link and the second movable link to rotate the grass cutting unit.

[0017] This allows the mowing unit to rotate relative to the second arm via the link mechanism, changing its angle. The link mechanism ensures reliable rotation of the mowing unit, and also allows the third hydraulic cylinder to be positioned as close as possible to the second arm, stably supporting the mowing unit. This ensures reliable operation of the mowing unit, allowing for stable mowing. [Effects of the Invention]

[0018] According to the present invention, the arm mechanism is operated by the hydraulic cylinder device of the arm mechanism, and the position of the mowing unit relative to the work vehicle and the angle of the cutter face of the mowing unit can be set to suit the working conditions. In particular, since the cutter face of the mowing unit can be adjusted to suit inclined surfaces, it is possible to mow on such surfaces and improve versatility. Furthermore, although hydraulic pressure is supplied from the external hydraulic supply unit of the work vehicle to the hydraulic motor and hydraulic cylinder device through a diverter valve, even when both the hydraulic motor and the hydraulic cylinder device are operated simultaneously, the diverter valve is a priority type diverter valve that preferentially directs a constant flow rate to the hydraulic cylinder device, so a necessary and sufficient amount of pressurized oil reaches the arm mechanism, which is subjected to more force than the mowing unit. This prevents the mowing unit from being improperly positioned and thereby ensures reliable mowing. Furthermore, since both the hydraulic motor and the hydraulic cylinder device can be operated using a single external hydraulic supply unit of the work vehicle, there is no need to provide a separate hydraulic supply unit dedicated to the hydraulic cylinder device or a separate hydraulic supply unit dedicated to the hydraulic motor on the work vehicle, which improves piping efficiency and versatility. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view showing a brush mowing device according to an embodiment of the present invention attached to a skid steer loader as a work vehicle, and showing an example of an initial attachment state and an operating state. [Figure 2] 1A and 1B show a grass cutting device according to an embodiment of the present invention, in which FIG. 1A is a front view and FIG. 1B is a side view. [Figure 3] 1 is a perspective view showing an example of an operating state of a grass mowing device according to an embodiment of the present invention. [Figure 4] 3 is a perspective view showing the attachment structure of the grass cutting unit to the second arm in the grass cutting device according to the embodiment of the present invention. FIG. [Figure 5] 1 is a hydraulic piping diagram of a grass mowing device according to an embodiment of the present invention. FIG. [Figure 6] FIG. 10 is a diagram showing a grass cutting device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a grass cutting device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIGS. 1 to 5, the brush mowing device S according to the embodiment is attached to a work vehicle W, such as a skid steer loader or a tractor, that has a specified attachment part Ta for attaching a work tool to the front of the vehicle body. Examples of the work tool include a shovel, a bucket, a pallet fork, a manifold fork, a harrow, and a ridger. The brush mowing device S according to the embodiment is attached to the specified attachment part Ta as one of the work tools. In the embodiment, the brush mowing device S is attached to, for example, a skid steer loader as the work vehicle W. As shown in FIGS. 1 and 5, the work vehicle W is equipped with an external hydraulic supply unit 1 that can supply hydraulic pressure to the outside. The external hydraulic supply unit 1 is equipped with a hydraulic pump 2 that is driven by power from an engine (not shown) of the work vehicle W and supplies hydraulic oil from a hydraulic tank 3. The external hydraulic supply unit 1 is equipped with a discharge port 4 that discharges hydraulic oil from the hydraulic pump 2 and a return port 5 that returns the hydraulic oil to the hydraulic tank 3, at the front of the work vehicle W. 1, reference numeral 6 denotes a connection part for electrical wiring. The brush cutting device S is driven by hydraulic pressure supplied from an external hydraulic pressure supply part 1 provided on this work vehicle W.

[0021] The grass mowing device S according to the embodiment includes a grass mowing unit 10. The grass mowing unit 10 includes a base 11 having an opening 12 that opens downward, a cutter 13 rotatably mounted on the base 11, a cover 14 that covers the cutter 13, and a belt transmission mechanism 16 that is mounted on the outside of the cover 14 at one end side of the rotation shaft 13a of the cutter 13 and rotates the rotation shaft of the cutter 13 using a hydraulic motor 15. In this grass mowing unit 10, the exposed part of the cutter 13 that faces the ground and is rotated by the hydraulic motor 15 to cut grass is referred to as a cutter surface 17.

[0022] The grass cutting device S also includes a base 20 that is attached to the specified attachment portion Ta via a connector 21. The base 20 is composed of a base 22 and a frame-shaped cover member 23 that covers the base 22. Mounting bodies 24, 26 are provided on one and the other of the cover member 23 of the base 20 in the front-rear direction of the work vehicle W, respectively, for detachably attaching to the front of the work vehicle W. In particular, the mounting bodies 24, 26 are configured to be attached to specified attachment portions (not shown) of a tractor. One mounting body 24 is provided on the top, and two are provided below, spaced a predetermined distance apart in the vehicle width direction. Similarly, one mounting body 26 is provided on the top, and two are provided below, spaced a predetermined distance apart in the vehicle width direction. As a result, by selecting either the front or rear mounting body 24, 26, the arm mechanism 30 (described below) and the grass cutting unit 10 can be selectively positioned on either the left or right side of the work vehicle W. Each figure shows the mounting body 24 of the base 20 attached to the specified mounting portion Ta of the work vehicle W via the coupler 21. The coupler 21 is a frame-shaped member and includes three supports 25 to which the mounting bodies 24, 26 are attached at positions corresponding to the mounting bodies 24, 26. In other words, the base 20 according to this embodiment is configured so that it can be directly attached to the specified mounting portion (not shown) of a tractor via the mounting bodies 24, 26, and is also configured so that it can be attached to a skid steer loader via the coupler 21.

[0023] Furthermore, the grass cutting device S is equipped with an arm mechanism 30, the base end of which is supported by the base 20, the grass cutting unit 10 attached to the tip end, and which uses a hydraulic cylinder device 40 to change the position of the grass cutting unit 10 relative to the work vehicle W and to change the angle of the cutter surface 17 of the grass cutting unit 10. The arm mechanism 30 is equipped with a first arm 31, the base end of which is supported by the cover member 23 of the base 20 so as to be rotatable about a first rotation axis J1, and a second arm 32, the base end of which is supported by the tip end of the first arm 31 so as to be rotatable about a second rotation axis J2, and the tip end of which is attached one end of the grass cutting unit 10 so as to be rotatable about a third rotation axis J3. In the grass cutting unit 10, the outer part of the cover 14 containing the belt transmission mechanism 16 is attached so as to be rotatable about the third rotation axis J3.

[0024] The first rotating shaft J1, second rotating shaft J2, and third rotating shaft J3 are arranged so that their axes are aligned in a direction perpendicular to the rotation shaft 13a of the cutter 13 of the grass cutting unit 10 and along the front-to-rear direction of the work vehicle W, allowing the grass cutting unit 10 to be operated on the side in the direction of travel of the work vehicle W. As a result, the grass cutting device S is dedicated to cutting grass on the side of the work vehicle W, but the structure can be simplified accordingly.

[0025] The hydraulic cylinder device 40 of the arm mechanism 30 is configured to include a first hydraulic cylinder 41 that is provided between the base 20 and the first arm 31 and changes the angle between them, a second hydraulic cylinder 42 that is provided between the first arm 31 and the second arm 32 and changes the angle between them, and a third hydraulic cylinder 43 that is provided between the second arm 32 and the mowing unit 10 and changes the angle between them. Each hydraulic cylinder 41, 42, 43 includes a cylinder and a piston, and the ends of these are rotatably supported.

[0026] In particular, the attachment relationship of the grass cutting unit 10 to the second arm 32 is as follows: That is, as shown in Figure 4, in this grass cutting device S, there are a pair of left and right fixed links 50, one end of which is fixed to the grass cutting unit 10 and the other end of which is supported rotatably about the third rotation axis J3, a pair of left and right first movable links 51, one end of which is provided at the tip of the second arm 32 near the base end side of the third rotation axis J3 so as to be rotatable about the first rotation axis K1, and one end of which is provided rotatably about the second rotation axis K2 installed on one end side of the fixed link 50 and the other end of which is provided at the tip of the second arm 32 so as to be rotatable about the second rotation axis K2. and a second movable link 52 rotatably mounted around a third rotation axis K3 mounted on the other end of the first movable link 51, and one end 43a of the third hydraulic cylinder 43 is rotatably mounted on and connected to a fourth rotation axis K4 mounted between the third rotation axis J3 of the first movable link 51 and the third rotation axis K3, so that the forward and backward movement of the third hydraulic cylinder 43 is transmitted to the fixed link 50 via the first movable link 51 and the second movable link 52, thereby rotating the grass cutting unit 10 relative to the second arm 32.

[0027] The grass cutting device S also includes a hydraulic drive unit 60 that is mounted on the base 22 of the base 20 and operates the hydraulic motor 15 of the grass cutting unit 10 and the hydraulic cylinder device 40 of the arm mechanism 30 based on hydraulic pressure supplied from the external hydraulic supply unit 1. As shown in detail in Figure 5, the hydraulic drive unit 60 is configured to include a flow dividing valve 61 that divides and supplies the hydraulic oil supplied from the external hydraulic supply unit 1 to the hydraulic motor 15 and the hydraulic cylinder device 40, and that preferentially supplies a constant flow rate to the hydraulic cylinder device 40, and a control unit 70 that controls the hydraulic oil supplied from the flow dividing valve 61 to the hydraulic cylinder device 40.

[0028] As the flow dividing valve 61, a variable dividing flow rate type is used, and it is equipped with an inlet port 62 for hydraulic oil from the external hydraulic supply unit 1, connected to the discharge port 4 of the external hydraulic supply unit 1, one outlet port 63 to the hydraulic motor 15 side, and the other outlet port 64 to the control unit 70 side, and is equipped with a pressure compensation spool variable throttle valve and a relief valve inside. Even if there are pressure fluctuations on the inlet port 62, one outlet port 63 and other outlet port 64 side, a constant flow rate can be preferentially flowed to the other outlet port 64, and the surplus flow rate can be flowed to the one outlet port 63.

[0029] Furthermore, the control unit 70 of the hydraulic drive unit 60 is provided with a first solenoid valve 71, a second solenoid valve 72, and a third solenoid valve 73, which are provided corresponding to the first hydraulic cylinder 41, the second hydraulic cylinder 42, and the third hydraulic cylinder 43, respectively, and which selectively supply the hydraulic oil supplied from the flow dividing valve 61 to each of the hydraulic cylinders 41, 42, and 43 to move them forward and backward. The hydraulic oil returning from the hydraulic motor 15, the first hydraulic cylinder 41, the second hydraulic cylinder 42, and the third hydraulic cylinder 43 is collected and returned to a return pipe connected to a return port 5 of the external hydraulic supply unit 1.

[0030] In addition, in this embodiment, the first solenoid valve 71, the second solenoid valve 72, and the third solenoid valve 73 are energized by wiring (not shown) connected to the connection part 6 (FIG. 1), and these valves are electrically controlled from the driver's seat side of the work vehicle W by a controller (not shown) connected to the connection part 6 (FIG. 1).

[0031] Therefore, when using this brush cutting device S, the following procedure is followed: As shown in Figure 1, first, the base 20 is attached to the specified mounting part Ta of the work vehicle W via the connector 21, and the required hydraulic piping is laid to the hydraulic drive unit 60 mounted on the base 20 so that hydraulic pressure is supplied from the external hydraulic supply unit 1 of the work vehicle W. Note that the required hydraulic piping can be laid in advance from the hydraulic drive unit 60 to the hydraulic motor 15 of the brush cutting unit 10 and the control unit 70 of the hydraulic cylinder device 40 of the arm mechanism 30 via a diverter valve 61.

[0032] 1 to 3, the arm mechanism 30 is operated by the hydraulic cylinder device 40 of the arm mechanism 30, the position of the mowing unit 10 relative to the work vehicle W and the angle of the cutter surface 17 of the mowing unit 10 are set to suit the work conditions, and the hydraulic motor 15 of the mowing unit 10 is driven to mow the grass with the mowing unit 10 while the work vehicle W is traveling as appropriate. In this case, because the cutter surface 17 of the mowing unit 10 can be adjusted to fit the slope, it can also be used to mow on this slope, improving versatility.

[0033] Furthermore, in this case, hydraulic pressure is supplied from the external hydraulic supply unit 1 of the work vehicle W to the hydraulic motor 15 through the flow diverter valve 61, and is also supplied from the control unit 70 to the hydraulic cylinder device 40 through this flow diverter valve 61, but even when both the hydraulic motor 15 and the hydraulic cylinder device 40 are operated simultaneously, the flow diverter valve 61 is a priority type flow diverter valve that preferentially flows a constant flow rate to the hydraulic cylinder device 40 side, so a necessary and sufficient amount of pressurized oil reaches the arm mechanism 30, which is subjected to more force than the grass cutting unit 10, and therefore it is possible to prevent a situation in which the grass cutting unit 10 is not positioned properly and grass is not cut sufficiently, and it is possible to reliably cut grass. Furthermore, because both the hydraulic motor 15 and the hydraulic cylinder device 40 can be operated using a single external hydraulic supply unit 1 of the work vehicle W, there is no need to provide a separate hydraulic supply unit dedicated to the hydraulic cylinder device 40 or a separate hydraulic supply unit dedicated to the hydraulic motor 15 on the work vehicle W, which improves piping efficiency and versatility.

[0034] Furthermore, when adjusting the angle of the mowing unit 10, the mowing unit 10 is rotated relative to the second arm 32 via a link mechanism, as shown in Figure 4. Because the link mechanism is used, rotation can be ensured and the third hydraulic cylinder 43 can be positioned as close to the second arm 32 as possible, which stably supports the mowing unit 10 and ensures reliable mowing.

[0035] Furthermore, in the above example, the mounting body 24 of the base 20 was attached to the specified mounting part Ta of the work vehicle W via the coupler 21, but it is also possible to attach the mounting body 26 of the base 20 to the specified mounting part Ta of the work vehicle W via the coupler 21. As a result, by selecting either the mounting body 24, 26 on one side or the other side in the front-to-rear direction of the base 20 and attaching the base 20 to the work vehicle W, it becomes possible to selectively position the arm mechanism 30 and the mowing unit 10 on either the left or right side of the work vehicle W depending on the mowing conditions, thereby improving versatility.

[0036] In the above embodiment, the arm mechanism 30 and the grass cutting unit 10 can be selectively positioned on either the left or right side of the work vehicle W by selecting either the front or rear mounting body 24, 26, but this is not necessarily limited to this. For example, as shown in Figure 6, the base 20 can be configured to include a base 80 having a mounting body 24 similar to that described above that can be attached to the work vehicle W, and a movable platform 82 that is rotatably supported on the base 80 around a vertical axis 81, and the above-mentioned arm mechanism 30 and hydraulic drive unit 60 can be mounted on this movable platform 82. The movable platform 82 can be configured to be able to be held in an appropriate rotation position, so that the grass cutting unit 10 can be positioned on either side of the work vehicle W, and modifications can be made as appropriate.

[0037] Furthermore, in the above embodiment, the grass cutting device S is applied to a skid steer loader as the work vehicle W, but this is not necessarily limited to this and may be used with other skid steer loaders having a different shape or size of the specified mounting portion Ta, or with work machines other than skid steer loaders, such as tractors, and modifications may be made as appropriate. The present invention is not limited to the above-described embodiment of the present invention, and those skilled in the art will easily make many modifications to these exemplary embodiments without substantially departing from the novel teachings and effects of the present invention, and these many modifications are within the scope of the present invention. [Explanation of symbols]

[0038] S Grass cutting device W Work Vehicle 1 External hydraulic supply 2 hydraulic pumps 3 Hydraulic tank 4 outlet 5 Return port 6 Connection 10 Grass-cutting unit 11 Foundation 12 Aperture 13 cutter 13a Rotation axis 14 Cover 15 Hydraulic motor 16 Belt transmission mechanism 17 Cutter surface 20 base 21 Connector 22 Foundation 23 Covering member 24 Mounting body 25 Support 26 Mounting body 30 Arm mechanism 31 First Arm 32 Second Arm J1 First rotating axis J2 Second rotating axis J3 3rd rotating axis 40 Hydraulic cylinder device 41 First hydraulic cylinder 42 Second hydraulic cylinder 43 Third hydraulic cylinder 50 Permalink 51 First movable link 52 Second movable link K1 First rotation axis K2 Second rotation axis K3 3rd rotation axis K4 4th rotation axis 60 Hydraulic drive unit 61 Diverter valve 62 Inlet port 63 One output port 64 other output port 70 Control Unit 71 First solenoid valve 72 Second solenoid valve 73 Third solenoid valve 80 foundations 81 Vertical axis 82 Movable platform

Claims

1. A brush cutting device that is attached as one of the implements to the front of a traveling work vehicle and is driven by hydraulic pressure supplied from an external hydraulic pressure supply unit provided on the work vehicle, the work vehicle includes a grass cutting unit having a cutter surface on which a cutter that faces the ground and is rotated by a hydraulic motor to cut grass is exposed; a base that is attached to the front of the work vehicle; an arm mechanism having a base end supported by the base and a tip end to which the grass cutting unit is attached, and having a hydraulic cylinder device that changes the position of the grass cutting unit relative to the work vehicle and changes the angle of the cutter surface of the grass cutting unit; and a hydraulic drive unit that is mounted on the base and operates the hydraulic motor of the grass cutting unit and the hydraulic cylinder device of the arm mechanism based on hydraulic pressure supplied from the external hydraulic supply unit, a hydraulic drive unit configured to divide and supply hydraulic oil supplied from the external hydraulic supply unit to the hydraulic motor and hydraulic cylinder device, and to supply a constant flow rate preferentially to the arm mechanism.

2. The arm mechanism is configured to include a first arm having a base end supported on the base so as to be rotatable around a first rotation axis, and a second arm having a base end supported on the tip end of the first arm so as to be rotatable around a second rotation axis, and having one end side of the grass cutting unit attached to the tip end so as to be rotatable around a third rotation axis, and the first rotation axis, the second rotation axis and the third rotation axis are arranged so that their axes are parallel to each other, The hydraulic cylinder device of the arm mechanism is configured to include a first hydraulic cylinder that is provided between the base and the first arm and that changes the angle between them, a second hydraulic cylinder that is provided between the first arm and the second arm and that changes the angle between them, and a third hydraulic cylinder that is provided between the second arm and the mowing unit and that changes the angle between them, 2. The brush mowing device according to claim 1, wherein the hydraulic drive unit comprises a first solenoid valve, a second solenoid valve and a third solenoid valve provided corresponding to the first hydraulic cylinder, the second hydraulic cylinder and the third hydraulic cylinder, respectively, for selectively supplying the hydraulic oil supplied from the flow dividing valve to each of the hydraulic cylinders.

3. 3. The grass cutting device according to claim 2, wherein the first, second and third rotating shafts are arranged so that their axes are aligned along the fore-and-aft direction of the work vehicle, and the grass cutting unit is operated on the side of the work vehicle in the direction of travel.

4. 4. The brush cutting device according to claim 3, wherein the base is provided with mounting bodies on one side and the other side in the longitudinal direction of the work vehicle, for detachably mounting the base to the front side of the work vehicle.

5. a fixed link having one end fixed to the mowing unit and the other end rotatably supported about the third rotating shaft; a first movable link having one end at the tip of the second arm, near the base end side of the third rotating shaft, so as to be rotatable about a first rotating shaft; and a second movable link having one end rotatably provided about the second rotating shaft on one end side of the fixed link, and the other end rotatably provided about a third rotating shaft at the other end of the first movable link; one end of the third hydraulic cylinder being rotatably provided about a fourth rotating shaft between the third rotating shaft and the third rotating shaft of the first movable link so as to be linked to the fourth rotating shaft, and the forward and backward movement of the third hydraulic cylinder being transmitted to the fixed link via the first movable link and the second movable link to rotate the mowing unit.

Images