Patent Description:
<CIT> discloses a work vehicle as specified in the preamble of claim <NUM>.

From <CIT>, there is known a work vehicle in which a front wheel portion that is in contact with ground during work is provided in front of a mower deck, the mower deck is supported so as to be suspended from an arm connected to the front wheel portion, an adjustment unit that adjusts a positional relationship between the front wheel portion in contact with the ground and the mower deck is provided on an upper portion of the mower deck, and a mowing height during the work can be adjusted by manually operating the adjustment unit in a state where the mower deck is raised.

However, in <CIT>, when the mowing height is to be adjusted, it is necessary to temporarily raise the mower deck and then get off the vehicle to manually adjust the mowing height, which is troublesome in operation.

In order to solve this problem, there may be provided a work vehicle including a mower deck in which an electric hydraulic cylinder is provided on the mower deck and is connected to an arm connected to a front wheel portion via a link such that a mowing height can be electrically changed by a switch operation. However, it is difficult to confirm how much the current mowing height is adjusted because of the electric switch operation.

An object of the invention is to provide a work vehicle capable of easily confirming how much a current mowing height is adjusted.

The invention provides a work vehicle according to claim <NUM>. Preferred embodiments are provided in the dependent claims.

Hereinafter, an embodiment of the invention will be described in detail with reference to the drawings. <FIG> shows a lawn mower as an example of a work vehicle according to the embodiment of the invention. In the following description, front-back, left-right, and up-down directions are defined based on a travel direction of the lawn mower.

As shown in <FIG>, the lawn mower according to the present embodiment includes a mower unit <NUM> below a front part of a traveling vehicle body <NUM>. A reference numeral <NUM> denotes a driving seat, and reference numerals <NUM> and <NUM> denote a front wheel and a rear wheel, respectively. In addition, the lawn mower includes, at a rear side thereof, a collector for temporarily accommodating cut grass. G is ground.

A structure of the mower unit <NUM> will be described in detail below with reference to <FIG>.

That is, <FIG> is a perspective view of the mower unit <NUM> according to the present embodiment. As shown in <FIG>, the mower unit <NUM> includes a deck portion <NUM>, a mowing mechanism <NUM>, front wheel portions <NUM> and <NUM>, front wheel arm portions <NUM> and <NUM>, rear arm portions <NUM> and <NUM>, and lifting arms <NUM> and <NUM>.

In the deck portion <NUM>, a cutting blade of the mowing mechanism <NUM> is accommodated below a top surface, and a power unit of the mowing mechanism <NUM>, the front wheel arm portions <NUM>, the rear arm portions <NUM>, the lifting arms <NUM>, and the like are disposed above the top surface in a state of being exposed to an outside.

The mowing mechanism <NUM> includes a power source such as a motor, the motor is operated by power supplied from the traveling vehicle body <NUM>, and thereby the cutting blade is rotated to mow the grass.

The front wheel portion <NUM> is provided on a front side of the deck portion <NUM>, and supports the front wheel arm portion <NUM> when the auxiliary wheel 12a comes into contact with the ground G during the mowing. In addition, the front wheel portion <NUM> includes a rotation mechanism 12b in which a rotation axis along an up-down direction is rotatably provided. The rotation mechanism 12b is connected to the auxiliary wheel 12a, and rotates following traveling of the traveling vehicle body <NUM> in the travel direction, thereby directing a direction of the auxiliary wheel 12a toward the travel direction.

The front wheel arm portion <NUM> is provided above the deck portion <NUM>, and one end (front end side) on a front side is connected to the front wheel portion <NUM>, and the other end (rear end side) on a rear side is connected to the rear arm portion <NUM>. Further, the front wheel arm portion <NUM> swings with respect to the deck portion <NUM> around a first connecting fulcrum <NUM> having a swing shaft along a left-right direction of the traveling vehicle body <NUM>.

Specifically, the first connecting fulcrum <NUM> is disposed close to a rear side between the front wheel portion <NUM> and the rear arm portion <NUM>.

The rear arm portion <NUM> is disposed on a rearward extension line of the front wheel arm portion <NUM> in a front-rear direction. Specifically, a front end side of the rear arm portion <NUM> is connected to the rear end side of the front wheel arm portion <NUM> via a rotation connecting portion <NUM>.

The rear arm portion <NUM> is swingably connected to the deck portion <NUM> at a second connecting fulcrum <NUM> located rearward than the front end side of the rear arm portion <NUM>. Further, a rear end side of the rear arm portion <NUM> is connected to the lifting arm <NUM> so as to be rotatable with the left-right direction as a rotation axis. Accordingly, the rear arm portion <NUM> swings in conjunction with the swing of the front wheel arm portion <NUM>.

Meanwhile, the lifting arm <NUM> is connected to the traveling vehicle body <NUM>, and raises and lowers the deck portion <NUM> by power supplied from the traveling vehicle body <NUM>. Specifically, a front end portion <NUM> of the lifting arm <NUM> is rotatably connected to the deck portion <NUM>, and the lifting arm <NUM> is rotatably connected to the rear arm portion <NUM> via a horizontal mechanism <NUM> on a rear side. Accordingly, the deck portion <NUM> is raised and lowered in accordance with raising and lowering of the lifting arm <NUM>.

When the lifting arm <NUM> is raised, a front portion of the deck portion <NUM> and the front wheel arm portion <NUM> are lifted up, and the front wheel portion <NUM> is separated from the ground G. At this time, the front wheel arm portion <NUM> and the rear arm portion <NUM> are in a posture of being protruded upward at the rotation connecting portion <NUM>.

On the other hand, when the lifting arm <NUM> is lowered from such a state, the front wheel portion <NUM> comes into contact with the ground G first. Then, at the same time that the front wheel portion <NUM> comes into contact with the ground G, the protruding shape formed by the front wheel arm portion <NUM> and the rear arm portion <NUM> becomes gentle.

In this way, a height on the front side of the deck portion <NUM> is substantially fixed. Then, when the lifting arm <NUM> is further lowered after the height of the deck portion <NUM> is substantially fixed, the horizontal mechanism <NUM> and the front end portion <NUM> of the lifting arm <NUM> are rotated to release energy generated in the deck portion <NUM> by the lowering.

At this time, when the horizontal mechanism <NUM> is a screw type, an angle of the deck portion <NUM> with respect to the ground G is determined by a degree of fastening of a screw.

Next, a mechanism for changing a mowing height will be described. That is, mowing height cylinders <NUM> that change a positional relationship between lower ends of the front wheel portions <NUM> and <NUM> and a lower end of the deck portion <NUM> are connected to the front wheel arm portions <NUM> and <NUM> via link mechanisms <NUM> and <NUM>, respectively. The mowing height cylinders <NUM> are provided at the front portion of the deck portion <NUM>.

<FIG> are views showing a right side of the mower unit <NUM>. <FIG> are views showing the right side of the mower unit <NUM> from which a right cylinder cover <NUM> is removed, and <FIG> are views showing the right side of the mower unit <NUM> to which the right cylinder cover <NUM> is attached. Reference numeral <NUM> denotes a left cylinder cover located on a left side.

<FIG> is a perspective view when viewed from a rear side to a front side. <FIG> is a perspective view when viewed from substantially an inside to the right side. <FIG> is an enlarged view of a part of <FIG>. <FIG> is a plan view, and <FIG> is a perspective view when viewed from a front outside to the rear side.

In these drawings, the link mechanism <NUM> will be described mainly with reference to <FIG>. The link mechanisms <NUM> have the same structure on left and right sides of the front portion the deck portion <NUM>, and each includes a first connecting fitting 16a, a connecting shaft 16c, a bracket 16b, a first connecting metal fitting 16d, a first connecting bolt 16e, a second connecting metal fitting 16f, a second connecting bolt <NUM>, and a third connecting metal fitting <NUM>.

That is, the first connecting fitting 16a having a <NUM>-shaped cross section (an upper portion has a box shape and a lower portion is a plate portion) is provided on a mowing height cylinder <NUM> side. The connecting shaft 16c penetrates the plate portion as the lower portion of the first connecting fitting 16a. The connecting shaft 16c is mounted on the front portion of the deck portion <NUM> so as to extend between the left and right sides, and is shared by the left and right link mechanisms <NUM> and <NUM>.

Left and right ends of the connecting shaft 16c are rotatably supported by the brackets 16b and 16b on the left and right sides of the deck portion <NUM>, respectively.

The first connecting metal fittings 16d are fixed to the connecting shaft 16c at positions close to the both ends of the connecting shaft 16c. Further, the second connecting metal fitting 16f is rotatably connected to the first connecting metal fitting 16d via the first connecting bolt 16e, and the third connecting metal fitting <NUM> is rotatably connected to the second connecting metal fitting 16f via the second connecting bolt <NUM>.

The third connecting metal fitting <NUM> is fixed to the front wheel arm portion <NUM>. Meanwhile, a front end of a rod 17a of the mowing height cylinder <NUM> is rotatably connected to the first connecting fitting 16a. That is, the front end of the rod 17a is inserted into the box-shaped portion at the upper portion of the <NUM>-shaped cross section, and is rotatably connected to a shaft 16a1 in the box-shaped portion.

A reference numeral <NUM> denotes a DC motor that drives the mowing height cylinder <NUM>, and a reference numeral <NUM> denotes an oil tank.

Here, a mechanism for adjusting the height of the deck portion <NUM> with respect to the ground G using the mowing height cylinder <NUM> will be described.

When the motor <NUM> is driven by a predetermined amount by a mowing height adjustment switch <NUM> (see <FIG>), the rod 17a of the mowing height cylinder <NUM> extends and contracts to a predetermined position. As a result, the shaft 16a1 in the box-shaped portion connected to the front end of the rod 17a moves, and the first connecting fitting 16a rotates to a predetermined position. Since the first connecting fitting 16a is fixed to the connecting shaft 16c, the connecting shaft 16c rotates by a predetermined amount. As a result, the first connecting metal fittings 16d fixed to both ends of the connecting shaft 16c are rotated. Due to the rotation, the second connecting metal fitting 16f is rotated via the first connecting bolt 16e. Due to the rotation, the third connecting metal fitting <NUM> is rotated via the second connecting bolt <NUM> and moves to a predetermined position. The rotational movement of the third connecting metal fitting <NUM> causes the front wheel arm portion <NUM> to move.

For example, when the rod 17a of the mowing height cylinder <NUM> extends, the first connecting fitting 16a rotates as indicated by an arrow A. Due to the rotation, the fixed connecting shaft 16c rotates in a direction of an arrow B. Due to the rotation, the first connecting metal fitting 16d rotates downward. Accordingly, the second connecting metal fitting 16f is pulled downward, and the third connecting metal fitting <NUM> also moves downward. As a result, the front wheel arm portion <NUM> moves downward as indicated by an arrow C. As a result, the front wheel portions <NUM> and <NUM> also move downward.

Herein, the connecting shaft 16c is rotatably supported on the deck portion <NUM> by the bracket 16b, and a fact that the front wheel portion <NUM> is moved downward due to the rotation of the members described above means that a deck portion <NUM> side is moved upward with respect to a front wheel portion <NUM> side. That is, when a lower end of the front wheel portion <NUM> is in contact with the ground G, the lower end of the deck portion <NUM> is at a high position with respect to the ground G, and the mowing height increases.

On the other hand, when the rod 17a of the mowing height cylinder <NUM> is contracted, the front wheel arm portion <NUM> moves upward due to the reverse rotation, and the lower end of the deck portion <NUM> is at a low position with respect to the ground G.

<FIG> is a schematic side view showing the low position, and a frame of each portion is schematically shown by a thick line. <FIG> is a schematic side view showing the lower end of the deck portion <NUM> is at the high position. As shown in <FIG> and <FIG>, even when the mowing height is changed by the cylinders <NUM>, a horizontal state of the deck portion <NUM> is maintained by the rotation and the movement of the members such as the lifting arms <NUM>, the front end portions <NUM> of the lifting arms <NUM>, the horizontal mechanisms <NUM>, the rear arm portions <NUM>, the second connecting fulcrums <NUM>, the rotation connecting portions <NUM>, the first connecting fulcrums <NUM>, and the front wheel arm portions <NUM>.

That is, the positional relationship between the lower ends of the front wheel portions <NUM> and the lower end of the deck portion <NUM>, specifically, a height of the lower end of the deck portion <NUM> is uniquely determined even when the mowing height is changed and adjusted.

Next, a mechanism in which how much the mowing height changed by the mowing height cylinder <NUM> as described above is adjusted can be easily confirmed will be described.

As shown in <FIG>, an indicator mechanism <NUM> is provided on a right side above the deck portion <NUM>. The indicator mechanism <NUM> includes a first connecting portion 25a, a first connecting screw 25b, a second connecting portion 25c, a second connecting screw 25d, a third connecting portion 25e, a third connecting screw 25f, a fourth connecting portion <NUM>, a fourth connecting screw <NUM>, a rotation shaft 25i, an indicator 25j, and a support plate <NUM>.

That is, the first connecting portion 25a is a plate piece fixed to the connecting shaft 16c, and the second connecting portion 25c is rotatably connected to the first connecting portion 25a by the first connecting screw 25b. The second connecting portion 25c is an L-shaped metal fitting, and is connected to one end of the rod-shaped third connecting portion 25e by the second connecting screw 25d. Further, the other end of the third connecting portion 25e is rotatably connected to the plate-shaped fourth connecting portion <NUM> by the third connecting screw 25f.

Further, the plate-shaped fourth connecting portion <NUM> is fixed to the plate-shaped indicator 25j by the fourth connecting screw <NUM>. The indicator 25j is supported by the rotation shaft 25i so as to be rotatable with respect to the support plate <NUM>. The support plate <NUM> is erected on the deck portion <NUM>.

Here, an upper end of the indicator 25j is bent outward in a right direction, and a front end 25j1 has a triangular shape.

The indicator 25j moves as follows. As described above, when the rod 17a of the mowing height cylinder <NUM> extends, the connecting shaft 16c rotates in the direction of the arrow B. As a result, the first connecting portion 25a fixed to the connecting shaft 16c rotates in a direction of an arrow (counterclockwise direction in the drawing), and the second connecting portion 25c and the third connecting portion 25e are pulled by the first connecting portion 25a and move in directions of arrows.

Accordingly, the fourth connecting portion <NUM> rotates clockwise with the rotation shaft 25i as a fulcrum. As a result, the indicator 25j also rotates in the clockwise direction as indicated by an arrow D. That is, the front end 25j1 of the indicator 25j moves rearward.

On the other hand, when the rod 17a of the mowing height cylinder <NUM> is contracted, the front end 25j1 of the indicator 25j moves forward due to the reverse rotation.

Next, the right cylinder cover <NUM> as shown in <FIG> will be described. The right cylinder cover <NUM> has a box shape, and is fixed to the deck portion <NUM> by a screw 24b in a state of covering an outer side portion of the mowing height cylinder <NUM>, an upper side of the front wheel arm portion <NUM>, and the indicator mechanism <NUM>. The left cylinder cover <NUM> covers the outer side portion of the mowing height cylinder <NUM> and the upper side of the front wheel arm portion <NUM>.

Further, a rectangular cutout window 24a is provided on an upper surface of the right cylinder cover <NUM>, and the front end 25j1 of the indicator 25j protrudes from a left half portion of the window 24a. Further, a scale plate <NUM> curved in an upward protruding shape is attached to a right half portion of the window 24a. That is, a front end 26a and a rear end 26b of the scale plate <NUM> are fixed to the right cylinder cover <NUM>, and the scale plate <NUM> is integrated with the right cylinder cover <NUM> (see <FIG>). Accordingly, the scale plate <NUM> can protect the mowing height cylinder <NUM> and the indicator mechanism <NUM>.

<FIG> are plan views of the scale plate <NUM>. A scale (in units of mm) indicating the height of the deck portion <NUM> from the ground G is marked. In the present embodiment, the scale is indicated in units of <NUM>. An adjustment of less than <NUM> is made by an operator by sense. Further, in a state where the scale plate <NUM> is mounted, a numerical value of a memo become smaller (lower) toward a front side and become larger toward a rear side.

As described above, since a movement of the front end 25j1 of the indicator 25j corresponds to the adjustment change of the mowing height of the deck portion <NUM> caused by the expansion and contraction of the rod 17a of the mowing height cylinder <NUM>, the current mowing height can be visually recognized at a glance by adjusting each connecting portion and the scale itself such that a scale value of the scale plate <NUM> pointed to by the front end 25j1 of the indicator 25j indicates the mowing height at that time.

The scale plate <NUM> will be further described below.

As shown in <FIG>, display intervals DS, DS, DS,. of the scale increase as the mowing height decreases. Accordingly, the closer to the ground G, the more finely the height can be adjusted.

Further, a movement direction (front-rear direction) of the front end 25j1 of the indicator 25j corresponds to a direction of a switch operation of the mowing height adjustment switch <NUM> (an example of a mowing height operation tool of the invention). That is, when the mowing height adjustment switch <NUM> is pushed forward, the front end 25j1 also moves forward, and when the mowing height adjustment switch <NUM> is pushed backward, the front end 25j1 also moves backward. The mowing height adjustment switch <NUM> is provided on an operation panel of the driving seat <NUM> of the traveling vehicle body <NUM>.

The indicator mechanism <NUM> can adjust the movement of the front end 25j1 of the indicator 25j, which is to accurately adjust a welding tolerance and an assembly tolerance between the deck portion <NUM> and the cylinder <NUM> or the link mechanism <NUM>.

That is, as shown in <FIG>, the indicator 25j and the fourth connecting portion <NUM> are connected to each other by the fourth connecting screw <NUM>. A long hole 25g1 is bored in the fourth connecting portion <NUM>, and a stroke of the indicator 25j can be adjusted by adjusting a position at which the fourth connecting screw <NUM> is screwed. <FIG> shows a front view and a side view of the fourth connecting portion <NUM>, and <FIG> shows the stroke.

Further, as shown in <FIG>, by adjusting the second connecting screw 25d, an initial position of the indicator 25j can be adjusted to coincide with the scale of the scale plate <NUM>. <FIG> shows the third connecting portion 25e and the second connecting screw 25d, and <FIG> shows an initial position (P) of the indicator 25j.

Further, as shown in <FIG>, a size of characters of the scale of the scale plate <NUM> is set such that a scale on a far side, that is, a scale of a lower mowing height in the present embodiment, is larger in size than that of a scale of a high mowing height in consideration of a line of sight (S) from the driving seat <NUM>. It is possible to make it easier to see a position far from the driving seat <NUM>, and in particular, to make it easier to adjust the lower mowing height.

Further, as shown in <FIG>, it is preferable that the upper surfaces of the right cylinder cover <NUM> and the left cylinder cover <NUM> are inclined obliquely downward from a front side to a rear side. Accordingly, when the grass rides on the covers <NUM> and <NUM> during the operation, the grass can slip down to a rear side of the traveling vehicle body <NUM>.

Further, as shown in <FIG>, the scale plate <NUM> is formed in an upwardly protruding arc shape. Accordingly, it can be expected that the grass slides down even when the grass rides on the scale plate <NUM>. The scale can be easily seen from the driving seat <NUM>.

Further, as shown in <FIG>, a rotation pitch M of the first connecting portion 25a is set to be constant, a rotation pitch N of the indicator 25j is set to a rotation pitch that is not constant. For example, even if the rotation pitch M is set to be constant, the rotation pitch N can be gradually changed from a large state to a small state. That is, when the first connecting screw 25b moves in an upper portion of a circular path U drawn by the first connecting screw 25b in a state where the rotation pitch M is constant, the movement of the fourth connecting portion <NUM>, that is, the movement of the indicator 25j is also large, and when the first connecting screw 25b is directed downward, the movement of the fourth connecting portion <NUM> starts to decrease, that is, the movement of the indicator 25j also decreases. In this way, the rotation pitch N can be set to the rotation pitch that is not constant.

By this contrivance, it is possible to implement the scale of the scale plate <NUM> in which when a pitch interval is small, the mowing height is high, and when the pitch interval is large, the mowing height is low as shown in <FIG>. That is, the indicator 25j is configured to move more at a position where a mowing height adjustment position is low than at a position where the mowing height adjustment position is high, and the interval of the scales pointed to by the indicator 25j is set to be larger at a position where the mowing height adjustment position is low than at a position where the mowing height adjustment position is high. In this way, the indicator 25j is set to move more at the position where the mowing height adjustment position is low than at the position where the mowing height adjustment position is high, and it is possible to easily confirm how much the mowing height is adjusted in fine adjustment at the position where the mowing height adjustment position is low.

Further, as shown in <FIG>, the two support plates <NUM>, which are L-shaped plates, are erected on the deck portion <NUM> so as to face each other. An interval space between the two support plates <NUM> is filled with the front wheel arm portion <NUM> in a free state. The support plate <NUM> functions to prevent the front wheel arm portion <NUM> from shaking in the left-right direction.

As described above, the indicator 25j is rotatably attached to the inner support plate <NUM> by the rotation shaft 25i. Therefore, the scale plate <NUM> can be disposed above the front wheel arm portion <NUM>, and can be disposed at a position that can be easily seen from the driving seat <NUM>. In addition, with such a configuration, the cylinders <NUM> and the link mechanisms <NUM> can be accommodated in the cylinder covers <NUM> and <NUM>, and both can be protected.

The cylinder <NUM> is not limited to being driven by a motor.

The invention can provide a work vehicle in which how much a current mowing height is adjusted can be easily confirmed, and therefore is optimal for a mower.

Claim 1:
A work vehicle comprising:
a traveling vehicle body (<NUM>); and
a mower unit (<NUM>) provided at the traveling vehicle body (<NUM>), wherein
the mower unit (<NUM>) includes: a deck portion (<NUM>) on which a mowing mechanism (<NUM>) that mows grass is provided, and a front wheel portion (<NUM>) provided in front of the deck portion (<NUM>) and configured to be in contact with ground during mowing work, and
the traveling vehicle body (<NUM>) includes a mowing height operation tool (<NUM>),
characterized in that
the mower unit (<NUM>) further includes:
a front wheel arm portion (<NUM>) connected, on a front end side thereof, to the front wheel portion (<NUM>) and swingably provided on the deck portion (<NUM>),
a mowing height cylinder (<NUM>) connected to the front wheel arm portion (<NUM>) via a link mechanism (<NUM>) and configured to change a positional relationship between a lower end of the front wheel portion (<NUM>) and a lower end of the deck portion (<NUM>), and
an indicator (25j) configured to move in conjunction with the mowing height cylinder (<NUM>),
wherein the mowing height operation tool (<NUM>) is configured to operate the mowing height cylinder (<NUM>).