Agricultural implement

Abstract

To provide an agricultural implement that allows a user to perform tension adjusting work of a winding member easily.SOLUTION: An agricultural implement includes a work part and a power transmission part for transmitting power to the work part. The power transmission part includes a plurality of rotation bodies arranged separately, an endless winding member wound between the plurality of rotation bodies, and a tension adjusting mechanism for adjusting tension of the winding member. The tension adjusting mechanism includes a tension imparting member for abutting against the winding member and imparting tension, an energizing member composed of a member whose energizing force changes by expansion and contraction for imparting energizing force to the tension imparting member for imparting tension, and a tension adjusting mechanism for adjusting the energizing force of the energizing member. The tension adjusting mechanism includes an energizing force adjusting member for adjusting the energizing force of the energizing member by adjusting the expansion and contraction length of the energizing member, and an indicator for indicating an adjusting position of the energizing force adjusting member where the energizing member imparts predetermined energizing force.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an agricultural machine, and more particularly to an agricultural machine equipped with a tension adjustment mechanism for adjusting the tension of a wrapping transmission device. [Background technology]

[0002] Conventionally, agricultural machines have been known that include a wrapping transmission device that transmits power to a working part and a tension adjustment mechanism that adjusts the tension of the wrapping transmission device (Patent Document 1). Patent document 1 describes an agricultural work machine equipped with a wrapping transmission device that transmits rotational power to a working part by means of a wrapping member (belt) wrapped around two rotating bodies (a drive pulley and a driven pulley), and a tensioner that applies tension to the wrapping member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-62627 A Summary of the Invention [Problem to be solved by the invention]

[0004] The tensioner has a biasing member for applying tension to the wrapping member, and is configured such that when the biasing member is adjusted to a predetermined length, the biasing force of the biasing member is adjusted and a predetermined tension is applied to the wrapping member. Therefore, when adjusting the tension of the wrapping member, the user needs to measure the length of the biasing member with a ruler or the like, making the task of adjusting the tension of the wrapping member a cumbersome task. Furthermore, this problem is not limited to belt drive mechanisms, but occurs in general in wrap-around transmission devices such as chain drive mechanisms.

[0005] Therefore, an object of the present invention is to solve the above problems and to provide an agricultural work machine that allows the user to easily adjust the tension of the wrapping member. [Means for solving the problem]

[0006] In order to solve such problems, the present invention has the following configuration. An agricultural work machine that is attached to a traveling machine body and performs a predetermined task while traveling together with the traveling machine body, A working unit and a power transmission unit that transmits power to the working unit, the power transmission unit includes a plurality of rotors arranged at a distance from one another, an endless winding member wound around the plurality of rotors, and a tension adjustment mechanism that adjusts the tension of the winding member; The tension adjustment mechanism includes: a tension applying member that applies tension to the wrapping member by contacting the wrapping member; A biasing member configured with a member whose biasing force changes by expansion and contraction and applies a biasing force to the tension applying member in order to apply the tension; a tension adjustment mechanism that adjusts the biasing force of the biasing member, The tension adjustment mechanism includes: A biasing force adjusting member that adjusts the biasing force of the biasing member by adjusting the extension length of the biasing member; and an index that indicates an adjustment position of the biasing force adjustment member at which the biasing member achieves a predetermined biasing force. Effect of the Invention

[0007] In the agricultural work machine of the present invention, the tension adjustment mechanism that adjusts the tension of the wrapping member has an index that indicates the index position of the biasing force adjustment member that adjusts the biasing force of the tensioning member, and when the user aligns the biasing force adjustment member with the index position, the tensioning member applies a predetermined biasing force and can apply an appropriate tension to the wrapping member. Therefore, the user does not need to measure the length of the tensioning member when adjusting the tension of the wrapping member, and convenience and workability for the user when adjusting the tension can be improved. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration of a grass cutter 1 according to an embodiment of the present invention. [Diagram 2] 2 is a diagram showing the wrapping transmission mechanism 22 of the grass mower 1 according to the embodiment of the present invention, in particular, a biasing force adjustment member 237. FIG. [Diagram 3] 2 is a diagram showing the wrapping transmission mechanism 22 of the grass mower 1 according to the embodiment of the present invention, in particular, a biasing force adjustment member 237. FIG. [Figure 4] 1 is a diagram showing a wrapping transmission mechanism 22, in particular an arm member 232, of the grass mower 1 according to an embodiment of the present invention. FIG. [Diagram 5] 1 is a diagram showing a working unit 30 of a grass cutter 1 according to an embodiment of the present invention. [Figure 6] FIG. 11 is a diagram showing an index 35 of a grass cutter 1 according to a modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment] Hereinafter, a grass cutter 1 according to an embodiment of the present invention will be described with reference to the drawings. The agricultural machine is not limited to a grass cutter, but may be any machine having a winding transmission device, such as a rotary cultivator or a harrow. In the following description, the same reference numerals in different drawings indicate parts having the same functions, and duplicated descriptions in each drawing will be omitted as appropriate. For the sake of convenience, terms indicating directions such as up, down, forward, backward, right, and left are used, but the direction in which gravity acts is downward, and the opposite is upward. The direction in which the traveling body moves is forward, and the opposite is backward. Furthermore, when facing forward, the right side is the right side, and the left side is the left side.

[0010] FIG. 1 is a diagram showing the configuration of the grass cutter 1 of this embodiment, where (a) is an oblique view of the grass cutter 1 seen diagonally from the upper left front, (b) is a view of the grass cutter 1 seen from the left side, and (c) is a view of the grass cutter 1 seen from above, and is an enlarged view of the area around the tension adjustment mechanism 23 with the belt 223 removed.

[0011] [Overall structure] As shown in FIG. 1, the grass cutter 1 of this embodiment performs grass cutting work while moving forward as the traveling body (not shown) travels, and is equipped with an attachment unit 10, a power transmission unit 20, a working unit 30 (see FIG. 5), and a cutting height adjustment unit 40.

[0012] [Installation part] The mounting unit 10 is connected to a three-point link mechanism (not shown) provided between two rear tires of the traveling body. The three-point link mechanism is usually composed of a top link, a lift rod, a lower link, etc. The three-point link mechanism is a well-known mechanism, so a detailed description will be omitted.

[0013] The mounting unit 10 includes a hitch frame 11, a top link connecting portion 12 connected to the top link, and a lower link connecting portion 13 connected to the lower link. The hitch frame 11 is a hollow cylindrical member extending in the left-right direction, which is a direction perpendicular to the traveling direction of the traveling machine body, from a gear box 21 (described later) of the power transmission unit 20. The top link connecting portion 12 is connected to the gear box 21, and the lower link connecting portion 13 is connected to the hitch frame 11. The top link connecting portion 12 and the lower link connecting portion 13 are respectively connected to the three-point link mechanism of the traveling machine body, so that the grass cutter 1 is connected to the rear of the traveling machine body so as to be able to rise and fall. The top link connecting portion 12 and the lower link connecting portion 13 may be connected to the three-point link mechanism of the traveling machine body via a known auto hitch arm.

[0014] [Power transmission section] Figures 2 and 3 both show the wrapping transmission mechanism 22 of the grass cutter 1 of this embodiment, in particular the spring force adjustment member 237, with (a) being a left side view when the belt cover 34 is not attached, and (b) being an explanatory diagram of the tension adjustment mechanism 23, and an enlarged cross-sectional view seen from below around the tension spring 233 (the tension roller 231 is omitted for convenience), with Figure 2 showing a state in which the spring force has not been properly adjusted, and Figure 3 showing a state in which the spring force has been properly adjusted. The power transmission unit 20 transmits power from a PTO shaft (not shown) provided on the running body via a universal joint (not shown) to the working unit 30, and includes a gear box 21, a transmission shaft inserted into the inside of the hitch frame 11 (extending to the left from the gear box 21 in this embodiment, not shown), a wrapping transmission mechanism 22, and a tension adjustment mechanism 23.

[0015] The gear box 21 is located approximately in the center of the hitch frame 11 extending laterally, and has a grass cutter input shaft 211 (see FIG. 1) to which power is transmitted from a PTO shaft provided on the traveling body via a universal joint (not shown), and a bevel gear (not shown) that receives the power of the grass cutter input shaft 211. The transmission shaft is connected to the bevel gear of the gear box 21, and transmits the power to the wrapping transmission mechanism 22.

[0016] [Wrapping transmission mechanism] The winding transmission mechanism 22 is housed in a belt cover 34 (see FIG. 1) fixed to a left side plate 33 (described later) of the working unit 30, and transmits power from the transmission shaft to a working rotor 31 (described later) of the working unit 30. The winding transmission mechanism 22 has a driving pulley 221 (rotating body), a driven pulley 222 (rotating body), and a belt 223 (endless winding member). The belt 223 is composed of three endless V-belts wound between the driving pulley 221 and the driven pulley 222. Power from the transmission shaft is transmitted to the driving pulley 221 via the driving pulley shaft 221a. Power from the driving pulley 221 is transmitted to the driven pulley 222 via the belt 223, and the power is transmitted from the driven pulley shaft 222a to the rotating shaft 311 of the working rotor 31. The driven pulley shaft 222a and the rotating shaft 311 are concentric.

[0017] 2 and 3, in the grass cutter 1 of this embodiment, a cooling fin 224 is fixed to the drive pulley 221 by bolts. The cooling fin 224 has a plurality of rotating blades 225, and when the drive pulley 221 rotates, the rotating blades 225 rotate together with the drive pulley 221 to cool the inside of the belt cover 34. The belt cover 34 is formed with an air vent 341 for releasing air from inside the belt cover 34 (see FIG. 1(b)).

[0018] [Tension adjustment mechanism] The tension adjustment mechanism 23 is a mechanism for adjusting the tension (tensile force) of the belt 223 of the wrapping transmission mechanism 22, and has a tension roller 231 (tension applying member) that applies tension to the belt 223 by urging the belt 223 from the inside to the outside of the belt 223, and an arm member 232 that supports the tension roller 231 so as to be freely rotatable. The tension adjustment mechanism 23 also has a tension spring 233 (biasing member) for applying a biasing force to the tension roller 231 relative to the belt 223, a long spring cover 234 (cylindrical accommodating member) that covers the tension spring 233, a rod member 236 inserted through the tension spring 233, a biasing force adjustment member 237 that is configured to be slidable on the rod member 236 (in the axial direction of the rod member 236) and can abut against one end 233a of the tension spring 233, a connecting member 238 that connects the rod member 236 and the arm member 232, and a support bracket 235 (support member) that supports the tension spring 233 via the spring cover 234 and supports the other end 233b of the tension spring 233.

[0019] The tension roller 231 is configured to come into contact with the inside of the belt 223 and apply tension to the belt 223 from the inside to the outside of the belt 223, and rotates following the rotation of the belt 223. The arm member 232 rotatably supports the tension roller 231 at one end, and the other end opposite to the side supporting the tension roller 231 is connected to the side plate 33 so that the arm member 232 can swing around the swing shaft 2321. A connecting hole (not shown) for connecting the connecting member 238 is formed in the end of the arm member 232 supporting the tension roller 231.

[0020] FIG. 4 is a diagram showing the wrapping transmission mechanism 22 of the grass cutter 1 of this embodiment, in particular the arm member 232, where (a) is a diagram showing the arm member 232 in the middle of being assembled, and (b) is a diagram showing the arm member 232 after assembly is completed. In this embodiment, the arm member 232 is configured to be separable into two members, a first arm member 232a that supports the tension roller 231 and a second arm member 232b that is provided with a swing shaft 2321. As shown in FIG. 4(b), the arm member 232 is configured by overlapping the first arm member 232a and the second arm member 232b and connecting and fixing them with two bolts 232c. When assembling the tension adjustment mechanism 23, first, the bolt holes on the drive pulley 221 side of the first arm member 232a and the second arm member 232b are overlapped with each other and fixed with the bolts 232c. Then, as shown in FIG. 4(a), the first arm member 232a is bent toward the drive pulley 221 to be in an inverted "L" shape (a non-tensioned state in which the tension roller 231 does not substantially apply tension to the belt 223). Next, the positions of the first arm member 232a and the second arm member 232b are adjusted so that the bolt holes on the belt side of the first arm member 232a and the second arm member 232b overlap, and this is fixed with the bolt 232c. As a result, the first arm member 232a and the second arm member 232b are connected in a substantially straight state, and the tension roller 231 is in a state of contact with the belt 223, and the tension roller 231 is in a tension state in which it can apply a strong tension to the belt 223. In this way, by making the arm member 232 a divided structure, when assembling the arm member 232 and the connecting member 238 to be connected to each other, the arm member 232 and the connecting member 238 can be first bent and assembled, and the assembling workability can be improved. This is particularly effective when the distance between the driving pulley 221 and the driven pulley 222 is narrow. It is also possible to configure the arm member 232 with only one member without making it a divided structure. In this case, the number of parts can be reduced compared to when the arm member 232 is divided, which is advantageous in terms of cost. Whether the arm member 232 is divided into a plurality of members or is formed of only one member may be determined appropriately taking into consideration the arrangement of the driving pulley 221 and the driven pulley 222, costs, and the like.

[0021] The tension spring 233 is a coil spring, and in this embodiment, is configured as a compression spring. Note that it is not limited to a compression spring, but may be a tension spring. Also, it is not limited to a coil spring, but may be one using an elastic body such as rubber. The spring cover 234 is configured in a cylindrical shape and accommodates the tension spring 233 therein. The spring cover 234 has a bottom plate portion 234a that abuts against the other end 233b of the tension spring 233 and through which the rod member 236 is inserted, and a cylindrical peripheral surface portion 234b that is connected to the bottom plate portion 234a and covers the outer periphery of the tension spring 233. In this embodiment, the bottom plate portion 234a and the peripheral surface portion 234b are integrally formed, but the bottom plate portion 234a and the peripheral surface portion 234b may be formed separately and then connected by welding or the like to integrally form the spring cover 234.

[0022] The end of the peripheral surface portion 234b opposite to the bottom plate portion 234a is an opening 234b1. The spring cover 234 protects the tension spring 233 and prevents the tension spring 233 from being significantly bent and deformed (buckling) due to vibrations generated during mowing work, etc. The cushion member 24 is fitted into the outer peripheral surface of the bottom plate portion 234a side of the spring cover 234. In this embodiment, the cushion member 24 is made of a ring-shaped rubber that goes around the outer periphery of the bottom plate portion 234a and the peripheral surface portion 234b of the spring cover 234. In addition, the end of the outer periphery of the cushion member 24 is fitted and fixed in an engagement groove 2351 formed in the support bracket 235. The cushion member 24 and the support bracket 235 may be fixed by adhesion, or conversely, there is no need to fix them to each other. A ring-shaped protrusion 24a protruding in the direction of expansion and contraction of the tension spring 233 is formed on the surface of the cushion member 24 on the bottom plate portion 234a side in order to prevent the washer 25 (described later) from slipping. In addition, a ring-shaped protrusion 234a1 protruding in the direction of expansion and contraction of the tension spring 233 is also formed on the bottom plate portion 234a. The protrusion 234a1 is inserted into a hole in the washer 25. That is, the protrusion 24a and the protrusion 234a1 form a ring-shaped recess, and the washer 25 is engaged and fixed in the recess formed by the protrusion 24a and the protrusion 234a1. The shape of the cushion member 24 is not limited to this. The cushion member 24 may be interposed between the spring cover 234 and the side plate 33 and between the spring cover 234 and the second surface portion 235b (described later) of the support bracket 235, and may be configured to have a plate-shaped rubber member interposed therebetween. The material of the cushion member 24 is not limited to rubber as long as it can maintain its function, and may be other elastic material, such as foamed resin.

[0023] The support bracket 235 is a member bent into a substantially L-shape, and is fixed by welding to the side plate 33 of the working unit 30. The support bracket 235 has a first surface 235a welded to the side plate 33 so as to be substantially perpendicular to the side plate 33, and a second surface 235b connected to the first surface 235a, bent in the extension direction of the tension spring 233 and substantially perpendicular to the first surface 235a, and disposed substantially parallel to the side plate 33. The first surface portion 235a is formed with a long hole (not shown) through which the rod member 236 is inserted. The rod member 236 is connected to the arm member 232 that swings and moves via the connecting member 238. Therefore, when the arm member 232 swings, the rod member 236 moves on a straight line extending in the longitudinal direction (direction parallel to the side plate 33) at the portion where the rod member 236 is inserted through the first surface portion 235a, and therefore a long hole that allows this movement is formed.

[0024] The first surface portion 235a supports the other end 233b of the tension spring 233 at a predetermined position via the bottom plate portion 234a of the spring cover 234. The position of the other end 233b of the tension spring 233 is limited and fixed by the first surface portion 235a. The spring cover 234 and the tension spring 233 housed in the spring cover 234 are disposed in the gap between the second surface portion 235b and the side plate 33. The second surface portion 235b has a function of restricting the movement of the tension spring 233 and the spring cover 234 when they vibrate during grass cutting work, etc. In other words, even if the tension spring 233 and the spring cover 234 vibrate and shake during grass cutting work, etc., the tension spring 233 and the spring cover 234 are configured to fit between the second surface portion 235b and the side plate 33 in the direction perpendicular to the direction in which the tension spring 233 expands and contracts.

[0025] In this embodiment, a washer 25 is interposed between the bottom plate portion 234a and the first surface portion 235a of the spring cover 234. When the rod member 236 moves along the long hole of the first surface portion 235a, the washer 25 can reduce friction when the spring cover 234 moves relative to the bottom plate portion 234a along with the movement of the rod member 236. In addition, a cushion member 24 is interposed between the spring cover 234 and the second surface portion 235b and the side plate 33, so that impact due to vibration or swing of the spring cover 234 (tension spring 233) is not directly transmitted to the second surface portion 235b and the side plate 33. In this embodiment, the spring cover 234 is held between the second surface portion 235b and the side plate 33 by the frictional force between the cushion member 24 and the second surface portion 235b and the side plate 33. The spring cover 234 is not a required component and can be omitted, but in a configuration in which the tension spring 233 protrudes outside the belt cover 34, as in the grass cutter 1 of this embodiment, it is preferable to provide the spring cover 234 so that the user does not directly touch the tension spring 233 during grass cutting work.

[0026] As described above, in this embodiment, the rod member 236 is inserted through the tension spring 233, and also through an elongated hole formed in the first surface portion 235a of the support bracket 235. The rod member 236 has a connecting member 238 attached to one end, and is connected to the arm member 232 via the connecting member 238. A screw groove 236a is formed on the outer circumferential surface on the other end side of the rod member 236, and constitutes a part of the biasing force adjustment member 237 described later.

[0027] [Force adjustment member] The biasing force adjustment member 237 has a screw groove 236a of the rod member 236, a nut portion 237a, and a collar portion 237b. The nut portion 237a is a grooved nut that screws into the screw groove 236a of the rod member 236. The collar portion 237b has a flange-shaped flange 237b1, one surface of which abuts against one end 233a of the tension spring 233 and the other surface of which abuts against the nut portion 237a. As described above, the position of the other end 233b of tension spring 233 in the expansion / contraction direction (axial direction of rod member 236) is limited by first surface portion 235a of support bracket 235, so that collar portion 237b and nut portion 237a are urged in a direction away from first surface portion 235a by the urging force of tension spring 233, and rod member 236 is urged in a direction pulling arm member 232. Then, urged rod member 236 urges arm member 232 clockwise as viewed from the left side via connecting member 238, and tension roller 231 urges belt 223 from the inside to the outside (in a direction to increase tension).

[0028] The collar portion 237b is formed longer than the spring length of the tension spring 233 adjusted to a predetermined biasing force, and when the tension spring 233 is adjusted to a predetermined biasing force, the tip of the collar portion 237b opposite the flange 237b1 protrudes from the long hole of the support bracket 235 (see FIG. 3(b)). When the nut portion 237a is rotated with a tool or the like, the mounting position of the nut portion 237a relative to the rod member 236 changes, and the collar portion 237b integrated with the nut portion 237a slides relative to the rod member 236. In this embodiment, the maximum outer diameter of the flange 237b1 and the nut portion 237a is configured to be smaller than the inner diameter of the opening 234b1 of the spring cover 234, and the flange 237b1 and the nut portion 237a are configured to be movable in the axial direction within the spring cover 234.

[0029] As described above, the position of the other end 233b of the tension spring 233 in the extension / contraction direction (axial direction of the rod member 236) is limited by the first surface portion 235a of the support bracket 235, so when the collar portion 237b slides, the tension spring 233 expands / contracts in response to the change in position of the flange 237b1. That is, by adjusting the position of the nut portion 237a of the biasing force adjustment member 237, the spring length of the tension spring 233 changes, and the biasing force can be adjusted. As described above, the tension spring 233 of this embodiment is configured as a compression spring, and by adjusting the mounting position of the nut portion 237a relative to the rod member 236 to contract the tension spring 233, the biasing force of the tension spring 233 increases, and by expanding the tension spring 233, the biasing force of the tension spring 233 decreases. In this embodiment, the collar portion 237b and the nut portion 237a of the biasing force adjustment portion 237 are fixed and configured as an integral body, but it is also possible to configure them as separate bodies. Also, the flange 237b1 of the collar portion 237b and the one end 233a of the tension spring 233 do not have to be in constant contact with each other, and it is sufficient that the flange 237b1 is in contact with the one end 233a of the tension spring 233 when the biasing force of the tension spring 233 is adjusted by the biasing force adjustment portion 237.

[0030] In this way, in the tension adjustment mechanism 23 of this embodiment, by adjusting the mounting position of the nut portion 237a of the biasing force adjustment member 237 relative to the rod member 236, the spring length of the tension spring 233 (the expansion and contraction length of the biasing member) can be adjusted, and the biasing force of the tension roller 231 relative to the belt 223 can be adjusted. Note that in the grass cutter 1 of this embodiment, a locking member 239 that screws into the rod member 236 and functions to prevent the nut portion 237a from loosening is provided, and after adjusting the mounting position of the nut portion 237a of the biasing force adjustment member 237 relative to the rod member 236, the locking member 239 is tightened to prevent the nut portion 237a from loosening, thereby allowing the biasing force of the tension roller 231 relative to the belt 223 to be maintained. The configuration of the tension adjustment mechanism 23 is not limited to the above, and it is also possible to adopt a configuration in which the rod member 236 is not inserted through the tension spring 233. Specifically, a rod-shaped member that is (approximately) parallel to the rod member 236 is provided on the support bracket 235, and the tension spring 233 is inserted through the rod-shaped member. In this case, the rod-shaped member and the rod member 236 are connected to one end 233a of the tension spring 233, and a slider that can slide between the rod-shaped member and the rod member 236 in the axial direction of both members is provided. The rod member 236 is provided with a biasing force adjustment member 237 that can slide on the rod member 236 and can come into contact with the slider. The slider is configured to be able to come into contact with one end 233a of the tension spring 233. The slider also slides in the axial direction of the rod member 236 as the position of the biasing force adjustment member 237 relative to the rod member 236 is adjusted. As a result, the slider comes into contact with one end 233a of the tension spring 233 and acts on the tension spring 233, thereby adjusting the spring length of the tension spring 233, that is, the biasing force of the tension spring 233.

[0031] [Working section] 5 is an explanatory diagram of the working unit 30 and the mowing height adjustment unit 40 of the grass cutter 1 of this embodiment, showing a cross section of the working unit 30 and the mowing height adjustment unit 40 cut along a straight line parallel to the traveling direction of the traveling body, viewed from the left. FIG. 5(a) shows a state in which the gap between the scraper body 431 and the gauge roller 41 is narrow, and FIG. 5(b) shows a state in which the gap between the scraper body 431 and the gauge roller 41 is wide. The working unit 30 performs grass cutting work using the power transmitted via the power transmission unit 20. The working unit 30 includes a working rotor 31, a shield cover 32, and a side plate 33.

[0032] The work rotor 31 includes a rotating shaft 311 having one end connected to the driven pulley 222 (driven pulley shaft 222a), disposed between the side plates 33 at both ends and extending in the left-right direction, and multiple grass-cutting blades 313 radially arranged on the rotating shaft 311. A plurality of brackets 312, each having a pair of support parts, are provided on the circumferential surface of the rotating shaft 311, and a grass cutting blade 313 is attached to the bracket 312. Note that Fig. 5 shows a state in which the work rotor 31 is rotating and the grass cutting blade 313 is extended outward by centrifugal force. Incidentally, instead of providing a plurality of brackets 312 each having a pair of support portions on the circumferential surface of rotating shaft 311, a plurality of pairs of protruding portions may be provided on the circumferential surface of rotating shaft 311. The grass cutting blade 313 is not limited to two overlapping bent blades as shown in Fig. 5, but may have any other shape or structure. Furthermore, the grass cutting blade 313 may be attached via a separate member such as a shackle or ring, rather than being directly attached to the bracket 312. In addition, the work rotor 31 in this embodiment rotates clockwise when viewed from the left, that is, in the same direction as the traveling direction of the traveling machine body.

[0033] The shield cover 32 is a cover member disposed to cover the front and the top of the work rotor 31. The shield cover 32 has the effect of preventing the scattering of weeds cut by the grass cutting blade 313, soil adhering to the weeds, and pebbles that have fallen to the work surface (ground surface), and also returns the cut weeds to the grass cutting blade 313 to crush them finely.

[0034] The side plates 33 are connected to and supported on both the left and right ends of the hitch frame 11. The side plates 33 rotatably support the rotating shaft 311 via ball bearings or the like, and also support the shield cover 32. In this embodiment, the wrapping transmission mechanism 22 is supported on the outer side of the left-end side plate 33. The hitch frame 11, the shield cover 32, and the side plates 33 function as a machine frame for the grass cutter 1.

[0035] [Mowing height adjustment section] The cutting height adjustment unit 40 is disposed behind the working unit 30 and adjusts the cutting height during grass cutting work. In this embodiment, the cutting height adjustment unit 40 includes a gauge roller 41, a roller support member 42, and a scraper 43. However, the configuration of the cutting height adjustment unit 40 is not limited to this example, and for example, the scraper 43 may be omitted.

[0036] The gauge roller 41 is a rotating body rotatably supported at both ends by the roller support member 42. The gauge roller 41 is in contact with the work area (ground) to be mowed, and rotates (rotates passively) following the progress of the mower 1 during mowing work. The roller support member 42 is supported on the left and right side plates 33 of the working unit 30 so as to be swingable about a swing fulcrum 421 (see FIG. 1(b)). An expandable member 44 (see FIG. 1(b)) is interposed between a scraper 43 (to be described later) and the upper part of the hitch frame 11 (a frame attached to the upper part of the gear box 21), and the height of the gauge roller 41 relative to the work rotor 31 can be adjusted by expanding and contracting the expandable member 44.

[0037] A scraper 43 for removing grass and soil adhering to the surface of the gauge roller 41 is fixed to the roller support member 42 so as to run along the gauge roller 41 while maintaining a predetermined gap therebetween. The scraper 43 has a scraper body 431 and scraper attachment parts 432 provided at both ends of the scraper body 431 for attaching and fixing the scraper body 431 to the roller support member 42. The scraper body 431 is made of a hollow square pipe. The gauge roller 41 is disposed so that one corner of the hollow square pipe is located at the lowest end in a side view (or rear view), and the one corner located at the lowest end of the hollow square pipe faces the gauge roller 41 closest to the gauge roller 41 and removes grass and soil adhering to the surface of the gauge roller 41. The scraper attachment parts 432 are flange-shaped members attached to both ends of the scraper body 431 by welding, and are fixed to the roller support member 42 by bolts 434. In this embodiment, the roller support member 42 is formed with a plurality of (two) long mounting holes 433 for adjusting the mounting position of the scraper mounting part 432, and as shown in Fig. 5, by changing the mounting hole 433 for fixing the scraper mounting part 432, the gap between the scraper 43 (scraper body 431) and the gauge roller 41 can be adjusted. Regardless of which mounting hole 433 is used for fixing, the corner of the square pipe is located at the lowest end.

[0038] [Adjusting the biasing force] In the grass cutter 1, the biasing force of the tension roller 231 against the belt 223 is not arbitrarily determined by the user, but is a predetermined biasing force that is suitable for design purposes and is determined in advance. In other words, by adjusting the biasing force of the tension spring 233 so as to achieve the predetermined biasing force, it is possible to apply an appropriate tension to the belt 223. As described above, the biasing force of the tension roller 231 against the belt 223 can be changed by adjusting the mounting position of the nut portion 237a of the biasing force adjustment member 237 relative to the rod member 236, and by adjusting the position of the flange 237b1 of the collar portion 237b on the rod member 236 to adjust the spring length of the tension spring 233. Therefore, in order to set the biasing force of the tension roller 231 against the belt 223 to a predetermined biasing force, it is sufficient to adjust the position of the flange 237b1 of the collar portion 237b and adjust the spring length of the tension spring 233 to correspond to the predetermined biasing force.

[0039] In the grass cutter 1 of this embodiment, the tension spring 233 is configured to correspond to a spring length corresponding to a predetermined spring force, and an indicator is provided to indicate the optimal position of the flange 237b1 relative to the rod member 236, so that the user can easily and quickly adjust the spring force of the tension spring 233.

[0040] Specifically, when the flange 237b1 is in an optimal position corresponding to the position of the index, for example, the abutment surface of the flange 237b1 with one end 233a of the tension spring 233 coincides with the position of the opening end 234b2, or the abutment surface of the flange 237b1 with the nut portion 237a coincides with the position of the opening end 234b2, the length of the spring cover 234 is designed so that the position of the flange 237b1 matches the position of the opening end 234b2 of the opening 234b1 of the spring cover 234. When the flange 237b1 is aligned with the opening end 234b2 (see FIG. 3), the spring length of the tension spring 233 is adjusted to a predetermined biasing force. That is, the open end 234b2 of the spring cover 234 functions as an indicator showing the adjustment position of the biasing force adjustment member 237, and the user can adjust the biasing force of the tension spring 233 to a predetermined biasing force simply by rotating the nut portion 237a to align the position of the flange 237b1 with the position of the open end 234b2 of the spring cover 234. At this time, it is preferable to color the open end 234b2 and the flange 237b1 so that they are easily visible. In this embodiment, the tension spring 233 is adjusted to have a predetermined biasing force by aligning the flange 237b1 with the opening end 234b2 of the spring cover 234, which serves as an index. However, it is also possible to configure the tension spring 233 to have a predetermined biasing force by aligning the nut portion 237a (end face of the nut portion 237a) with the opening end 234b2 of the spring cover 234, which serves as an index.

[0041] [Modification of indicators] FIG. 6 is a diagram showing an index 35 of the grass cutter 1 according to modified examples, with (a) and (b) showing two modified examples. In the above embodiment, the open end 234b2 of the tension spring 233 is used as a position indicator for adjusting the biasing force of the tension spring 233, but other aspects are also possible. For example, as shown in FIGS. 6(a) and 6(b), a triangle mark (.DELTA.) is provided on the side plate 33 as the indicator 35. As shown in FIG. The △ mark of this indicator 35 is provided by forming a triangular protrusion on the side plate 33. Note that the configuration is not limited to forming a protrusion, and a recess may be formed, a △-shaped paint may be applied, or a △-shaped sticker may be attached, and any other shape that can form an indicator may be used. The shape of the indicator 35 is also not limited to a △, and may be an arrow, a line, or any other shape that can clearly indicate the position. The indicator 35 may also be colored to improve visibility.

[0042] In FIG. 6(a), a long hole 234b3 is provided in the axial direction in part of the spring cover 234 so that the internal tension spring 233, collar portion 237b, and nut portion 237a can be seen, and the position of the flange 237b1 of the collar portion 237b visible from the long hole 234b3 is aligned with the position of the indicator 35, thereby adjusting the biasing force of the tension spring 233 to a predetermined biasing force. 6(b) shows a configuration in which the spring cover 234 is not provided, and the biasing force of the tension spring 233 is adjusted to a predetermined biasing force by aligning the position of the flange 237b1 of the collar portion 237b with the position of the index 35. In this configuration, since the spring cover 234 is not provided, the support bracket 235 is made up only of the first surface portion 235a, and the cushion member 24 is not used.

[0043] In addition, a mark indicating the position of the flange 237b1 where the biasing force of the tension spring 233 becomes a predetermined biasing force may be provided on the rod member 236 and used as a position index. Also, a notch or a protrusion may be provided on the open end 234b2 of the spring cover 234, and the tip of the notch or the protrusion may be used as a position indicator. Furthermore, in the above-mentioned modified example, the flange 237b1 is used to adjust the biasing force of the tension spring 233, but this is not limited to this, and for example, a position indicator that indicates the position of the nut portion 237a may be used to adjust the biasing force of the tension spring 233. In addition to this, any member that is correlated with the spring length of the tension spring 233 can be used as a means for adjusting the biasing force of the tension spring 233.

[0044] In the above-described embodiment, a belt drive mechanism composed of a drive pulley, a driven pulley, and an endless V-belt is used as the winding transmission mechanism, but it is not limited to a V-belt and may be a flat belt, a hexagonal belt, a toothed belt, etc. Furthermore, it is not limited to a belt drive mechanism and may be a chain drive mechanism composed of a drive sprocket, a driven sprocket, and an endless chain, etc.

[0045] As described above, the grass cutter 1 according to the embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to these embodiments and modifications, and the present invention includes design changes and the like that do not deviate from the gist of the present invention. In addition, the above-mentioned embodiments and modifications can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0046] 1. Grass trimmer 10. Mounting Part 11 Hitch frame 12 Top link connection 13 Lower link connection 20 Power transmission section 21 Gearbox 211 Grass trimmer input shaft 22 Winding transmission mechanism 221 Drive pulley 221a Drive pulley shaft 222 Driven pulley 222a Driven pulley shaft 223 Belt 224 Cooling fin 225 Rotating Blade 23 Tension adjustment mechanism 231 Tension roller 232 Arm member 232a First arm member 232b Second arm member 232c Bolt 2321 Swing shaft 233 Tension Spring 233a one end 233b other end 234 Spring cover 234a Bottom plate part 234a1 Convex 234b Peripheral part 234b1 opening 234b2 Open end 234b3 long hole 235 Support bracket 235a First side 235b 2nd side 2351 Engagement groove 236 Rod member 236a Thread groove 237 Force adjustment member 237a Nut 237b Color section 237b1 Brim 238 Connecting members 239 Anti-loosening material 24 Cushioning material 24a Convex 25 Washer 30 Working Section 31 Working rotor 311 Rotational axis 312 Bracket 313 Grass cutting blade 32 Shield cover 33 Side Panel 34 Belt cover 341 Vent 35 indicators 40 Mowing height adjustment unit 41 Gauge roller 42 Roller support member 421 Swing Support Point 43 Scraper 431 Scraper body 432 Scraper attachment part 433 Mounting hole 434 Volts 44 Elastic member

Claims

1. An agricultural work machine that is attached to a traveling machine body and performs a predetermined task while traveling together with the traveling machine body, A working unit and a power transmission unit that transmits power to the working unit, the power transmission unit includes a plurality of rotors arranged at a distance from one another, an endless winding member wound around the plurality of rotors, and a tension adjustment mechanism that adjusts the tension of the winding member; The tension adjustment mechanism includes: a tension applying member that applies tension to the wrapping member by contacting the wrapping member; A biasing member configured with a member whose biasing force changes by expansion and contraction and applies a biasing force to the tension applying member in order to apply the tension; a tension adjustment mechanism that adjusts the biasing force of the biasing member, The tension adjustment mechanism includes: A biasing force adjusting member that adjusts the biasing force of the biasing member by adjusting the extension length of the biasing member; and an index that indicates an adjustment position of the biasing force adjustment member at which the biasing member achieves a predetermined biasing force.

2. The tension adjustment mechanism further includes a rod member that applies a biasing force of the biasing member to the tension applying member, the biasing force adjustment member is attached to the rod member and abuts against one end of the biasing member, and the biasing force of the biasing member is adjusted by adjusting an attachment position of the biasing force adjustment member; 2. The agricultural machine according to claim 1, wherein the index indicates a mounting position of the biasing force adjustment member.

3. Further equipped with a fuselage frame, the tension adjustment mechanism further includes a support member fixed to the aircraft frame and supporting an end of the urging member opposite to the one end, The support member includes a first surface portion that supports the other end at a predetermined position in the extension / contraction direction of the biasing member; 3. The agricultural machine according to claim 2, further comprising: a second surface portion that limits movement of the urging member in a direction perpendicular to the extension / contraction direction of the urging member.

4. 4. The agricultural machine according to claim 3, wherein a washer is interposed between the biasing member and the first surface portion.

5. The tension adjustment mechanism further includes a cylindrical housing member that houses at least a portion of the biasing member, 5. The agricultural machine according to claim 1, wherein the biasing force adjustment member is configured to be movable within the housing member.

6. The tension adjustment mechanism further includes a housing member that houses at least a portion of the biasing member, 5. An agricultural machine according to claim 1, wherein the index is provided on the storage member.

7. The housing member is configured in an elongated shape, 7. The agricultural machine according to claim 6, wherein one end of the storage member functions as the indicator.

8. the biasing member is disposed between the aircraft frame and the second surface portion, 4. The agricultural machine according to claim 3, wherein cushion members are interposed between the biasing member and the machine body frame, and between the biasing member and the second surface portion.

9. The tension adjustment mechanism further includes a cylindrical housing member that houses at least a portion of the biasing member, 9. The agricultural machine according to claim 8, wherein the cushion member is configured in a ring shape that goes around the accommodating member.

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