Tail wheel mechanism and agricultural work machine having the same

Abstract

To provide a tail wheel mechanism and an agricultural work machine having the same which can be easily handled while being applied to various ridge heights.SOLUTION: A tail wheel mechanism H provided to a cover body G covering an upper part of a reap blade part F having a plurality of rear blades 23, includes: a first link 43 which is rotatable at a right-left middle part of an upper part of the cover body G; a second link 44 rotationally provided to a lateral side of the cover body G at a lower part of the cover body G; a tail wheel frame 45 provided on a right and left in a travel direction in parallel with the cover body G and connecting the first link 43 and the second link 44; a telescopic means (vertical moving means) 41 which connects the upper side of the cover body G and the first link 43 and which moves the tail wheel frame 45 in a vertical direction by the telescopic movement; and a grounding means 51 for fixing an upper part of the tail wheel frame and grounding the lower part on the ground to be capable of adjusting the reap height of the reap blade part by the telescopic means (vertical moving means) 41.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tail wheel mechanism and an agricultural working machine having a tail wheel mechanism, and more particularly to a tail wheel mechanism provided at the rear of an agricultural working machine and an agricultural working machine having a tail wheel mechanism at the rear. [Background technology]

[0002] Patent Document 1 discloses a working machine capable of cutting the stalks and vines of crops growing above ground while maintaining the cutting blade height relative to the ridges. According to this, a sensor roller that rolls on the top surface of the ridges behind the flail mower body attached to the rear of the tractor is provided, and a detection signal issued in response to the up and down movement of the sensor roller is fed back to a hydraulic control valve of a hydraulic cylinder device of the tractor to move the flail mower body up and down. The height of the flail mower body relative to the ridges is adjusted by raising and lowering a tail wheel supported by a first link arm and a second link arm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-287518 A Summary of the Invention [Problem to be solved by the invention]

[0004] The second link arm, which rotates under the cover plate that covers the entire top surface of the flail blade, is located at the center of the cover plate. In other words, the second link arm is located at the center of the flail blade that rotates on the left-right axis, and is located behind it. The second link arm is prone to vines cut by the flail blade adhering to it, which takes time to remove, making maintenance inefficient. In addition, the ridge height may differ depending on the region, and it is thought that a single positional relationship between the cutting blade and the tail wheel cannot accommodate various ridge heights. In the first place, when the surface of a field is covered with crop stalks and vines growing above ground, it is difficult for workers to judge the correct position of the ridges, and they may end up misjudging the position of the ridges. Therefore, the present invention has been made in consideration of the above-mentioned problems, and has an object to provide a tail wheel mechanism that is adaptable to various ridge heights and easy to handle.

[0005] The present invention has been made with attention to the above-mentioned problems, and aims to provide a ridge height detection device that can properly measure the height of the ridge top surface even if the relative positional relationship in the width direction to the ridge differs. [Means for solving the problem]

[0006] The present invention relates to A tail wheel mechanism provided on a cover body that covers an upper portion of a cutting blade unit having a plurality of cutting blades, a first link that is rotatable at a left-right intermediate portion of an upper portion of the cover body; a second link provided rotatably on a side of the cover body at a lower portion of the cover body; A tail wheel frame is provided on the left and right sides of the traveling direction in parallel with the cover body and connects the first link and the second link; An extension / contraction means for connecting an upper portion of the cover body to the first link and extending / contracting to move the tail wheel frame up and down; a grounding means for fixing an upper part to the tail wheel frame and grounding a lower part to the ground, the grounding means being capable of adjusting the cutting height of the cutting blade portion by the extension and contraction means; A tail wheel mechanism comprising: relates to.

[0007] The present invention further comprises: The grounding means includes a holder fixed to the tail wheel frame; an arm that is movable in a vertical direction relative to the holder and is provided so that its position can be fixed relative to the holder; a wheel rotatably provided at a lower end of the arm and capable of rolling when in contact with the ground; A tail wheel mechanism comprising: relates to.

[0008] The present invention further comprises: The grounding means includes a scraper disposed adjacent to the wheel; A tail wheel mechanism comprising: relates to.

[0009] The present invention further comprises: The wheels are provided so as not to be rotatable in the horizontal direction. A tail wheel mechanism comprising: relates to.

[0010] The present invention further comprises: The wheels are provided so as to be rotatable in a horizontal direction. A tail wheel mechanism comprising: relates to.

[0011] The present invention relates to A tail wheel mechanism provided on a cover body that covers an upper portion of a cutting blade unit having a plurality of cutting blades, a first link that is rotatable at a left-right intermediate portion of an upper portion of the cover body; a second link provided rotatably on a side of the cover body at a lower portion of the cover body; A tail wheel frame is provided on the left and right sides of the traveling direction in parallel with the cover body and connects the first link and the second link; An extension / contraction means for connecting an upper portion of the cover body to the first link and extending / contracting to move the tail wheel frame up and down; a grounding means for fixing an upper part to the tail wheel frame and grounding a lower part to the ground, the grounding means being capable of adjusting the cutting height of the cutting blade portion by the extension and contraction means; An agricultural machine having a tail wheel mechanism, relates to. Effect of the Invention

[0012] According to the present invention, a tail wheel mechanism and an agricultural machine having a tail wheel mechanism are provided that are adaptable to a variety of ridge heights and easy to handle. [Brief description of the drawings]

[0013] [Figure 1] 1 is a side view of an agricultural machine according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a rear view of an agricultural machine according to a first embodiment of the present invention. [Diagram 3] 1 is a plan view of an agricultural machine according to a first embodiment of the present invention. [Figure 4] FIG. 2 is a rear view showing the positional relationship between the cutting blade unit and the ridges of the agricultural machine according to the first embodiment of the present invention. [Diagram 5] 1 is a side cross-sectional view of a main part of an agricultural machine according to a first embodiment of the present invention, showing the right side of a pair of sides. [Figure 6] 1 is an enlarged rear view of a main portion of an agricultural machine according to a first embodiment of the present invention. [Figure 7] 1 is an enlarged rear view of a main part of the agricultural work machine according to the first embodiment of the present invention, showing a case in which the cover body is slightly displaced from the left-right center of the ridge. [Figure 8] 1 is an enlarged rear view of a main part of the agricultural work machine according to the first embodiment of the present invention, showing a case in which the cover body is significantly displaced from the left-right center of the ridge. [Figure 9] 13 is a side cross-sectional view of a main part of an agricultural machine according to a second embodiment of the present invention. [Figure 10] 13 is an enlarged rear view of a main portion of an agricultural machine according to a second embodiment of the present invention. [Figure 11] Fig. 2 is a side view of the agricultural work machine according to the first embodiment of the present invention, showing the operating range of the tail wheel mechanism with the cutting blade unit in the lowest position. [Figure 12] Fig. 2 is a side view of the agricultural work machine according to the first embodiment of the present invention, showing the operating range of the tail wheel mechanism with the cutting blade unit in the raised position. [Figure 13] 13 is a side view of an agricultural machine according to a third embodiment of the present invention, showing a third embodiment of a tail wheel mechanism lifting means. [Figure 14] 13 is a side view of an agricultural machine according to a fourth embodiment of the present invention, showing a fourth embodiment of a ground contact means of a tail wheel mechanism. [Figure 15] 13 is a side view of an agricultural machine according to a fifth embodiment of the present invention, showing a fifth embodiment of a ground contact means of a tail wheel mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A ridge height detecting device B according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 8. The agricultural work machine A to which the present invention is applied places the cutting blade unit F on the ridges, grounds the grounding means of the tail wheel mechanism H against the ridge bottom U2 on the side of the ridge, and moves forward while rotating the cutting blade 23 of the cutting blade unit F, thereby crushing the stalks and vines of sweet potato plants growing in the ridges. The ridges may or may not have mulch film laid on them, and the present invention is applicable to either form.

[0015] First, an overall outline of the ridge height detection device B of the agricultural machine A will be described. The agricultural machine A has a ridge height detection device B, a mounting section C, a speed change section D, a transmission device E, a cutting blade section F, a cover body G, and a tail wheel mechanism H. For the sake of expression, when written as left or right, it corresponds to the left and right in the width of the traveling direction, and when written as up or down, it is explained that the direction approaching the ground is down, and the direction away from the ground is up. Also, when written as front or rear, it is explained that it corresponds to the front and rear in the traveling direction. Also, regarding the symbols used, L or R may be added to the end of the symbols attached to similar parts to express them as a distinction. On the other hand, by not adding L or R, it may be expressed without distinguishing the parts. For example, in the case of parts XL and part XR, of the pair of left and right parts X, the left part is classified as XL and the right part is classified as XR, and when there is no distinction between left and right, it is expressed as part X.

[0016] The mounting part C will now be described. As shown in FIG. 1, the mounting part C is connected to a lifting device of the traveling body (not shown) to lift the agricultural work machine A. The transmission D is disposed approximately in the center of the mounting part C. The transmission D has an input shaft 11 that obtains power from a traveling machine body such as a tractor, and the agricultural work machine A obtains driving force by rotating the input shaft 11 with the power of the traveling machine body. The transmission D changes the speed of the driving force and outputs it to the transmission device E.

[0017] The transmission device E will now be described. 1 to 3, the transmission device E is disposed on the side of the agricultural work machine A. The transmission device E has a pulley (not shown) and a belt (not shown), and further changes the speed of the power obtained from the speed change unit D and transmits the rotational power to the cutting blade unit F.

[0018] The cutting blade F will now be described. 4, the cutting blade unit F has a rotor shaft 21, a holder 22, and a cutting blade 23, and is located between side plates G1 of a cover body G described below. The rotor shaft 21 is a cylindrical shaft located between the side plates G1 of the cover body G, arranged horizontally and parallel to the width direction of the moving direction, and is supported for free rotation. One end of the rotor shaft 21 is connected to a transmission device E, and can be rotated by power obtained from the traveling machine body. Holders 22 are arranged on the rotor shaft 21 at intervals in the circumferential and axial directions of the rotor shaft 21. A cutting blade 23 capable of cutting vegetation is attached to the holder 22. The cutting blade 23 is rotatable relative to the holder 22, and as the rotor shaft 21 rotates, the cutting blade 23 is pulled in the radial direction by centrifugal force, and cuts vegetation with the blade at the tip. When the cutting blade 23 comes into contact with a foreign object such as an obstacle, the cutting blade 23 rotates backward in the rotational direction, preventing the impact from being transmitted to the rotor shaft 21 and the entire agricultural work machine A.

[0019] As shown in Fig. 4, the cutting blade unit F in this embodiment of the invention is arranged so that the rotational area F1 of the cutting blade 23 at the axial center of the rotor shaft 21 is smaller than the rotational area F1 of the other cutting blades 23. In other words, the cutting blade 23 located on the ridge top surface U1 has a smaller rotational radius, and the cutting blade 23 located outside the ridge top surface U1 has a larger rotational radius. This allows the cutting blade 23 to be aligned with the rotational area F1 from the top surface of the ridge through the shoulder portion U5 of the ridge to the upper portion of the ridge side surface U3. As a result, the stems and vines to be treated that grow from the top of the ridge to the bottom U2 of the ridge can be cut. Furthermore, by providing rotation areas with different rotation radii, it is possible to absorb some deviations of the stalks and vines of sweet potatoes growing from the ridges, even if they shift to the side from the center of the ridges U1. Also, the rotation area F1 does not have to completely match the shape of the ridges U. In this way, even if the cutting blade portion F shifts relatively to the left or right with respect to the traveling direction with respect to the ridges U, the cutting blade 23 is prevented from coming into contact with the upper surface U1 of the ridges.

[0020] The cover body G will be described. The cover body G is disposed so as to cover the upper part of the cutting blade part F, so that the cut vegetation or the cut stems and vines are not scattered around. Also, by guiding the cut stems and vines to the rear lower part, toward the bottom of the ridge U2, the cut stems and vines are not left on the ridge U. The cover body G is equipped with a divider G2. A pair of dividers G2 are provided on the left and right sides of the ridges, and are long members that protrude from the rear of the cover body G to the front of the cover body G. The lower end of the divider G2 moves forward while touching the bottom of the ridge U2 or being slightly buried in it, thereby raising up the stems and vines of vegetation that are growing on the ridges and on both sides of the bottom of the ridge U2, and collecting them while guiding them to the top of the ridge U. The stems and vines collected by the divider G2 are crushed by the cutting blade F.

[0021] The tail wheel mechanism H will now be described. A tail wheel mechanism H is disposed at the rear of the cover body G, and the tail wheel mechanism H is provided on the cover body G which covers the upper part of the cutting blade unit F having a plurality of cutting blades 23. The ground contact means 51, which is made up of wheels provided on the tail wheel mechanism H, comes into contact with the ground, and the ground contact means 51 rolls as the machine moves forward. The ground contact means 51 can be moved up and down relative to the cover body G by the lifting means 41. In other words, by moving the ground contact means 51 up and down while it is in contact with the ground, the cutting blade portion F moves up and down. That is, the cutting height can be adjusted by the ground contact means 51. A detailed description of the tail wheel mechanism H will be given later.

[0022] The ridge height detection device B will now be described. The ridge height detection device B is installed at the rear of the cover body G, as shown in Fig. 1. As shown in Fig. 2 and subsequent figures, the ridge height detection device B has a support base 31 having a slide rail 32, a sensor bracket 33 to which a sensor 36 is fixed, a first arm 34A connected to the support base 31, a second arm 34B connected to the first arm 34A, a third arm 34C connecting the support base 31, the sensor bracket 33 and the second arm 34B, and a guide arm 34D having a guide means 34E connected to the first arm 34A and in contact with the side of the ridge.

[0023] The support base 31 in the ridge height detection device B will be described. 2 and 5 to 10, the support base 31 in the ridge height detection device B is a member attached to the rear center of the cover body G. The support base 31 is fixed to the cover body G by a fixing member 37 located at the front. A slide rail 32, a first arm 34A, and a third arm 34C are attached to the portion of the support base 31 facing rearward. The support base 31 is attached to the rear of a cover body G that covers the upper part of the cutting blade unit F having a plurality of cutting blades 23, and has slide rails 32 fixed thereto with their longitudinal directions arranged parallel to the left and right of the traveling direction. G3 is the rear lower end of the cover body. The rear lower end G3 of the cover body supports the divider G2 and increases the strength of the cover body G.

[0024] The slide rail 32 in the ridge height detection device B will be described. A slide rail 32 that enables a sensor bracket 33 (described later) to slide in the left-right direction is fixed to the support base 31. The slide rail 32 has a U-shaped cross section in a side view, and its long dimension is oriented horizontally to the left and right of the traveling direction.

[0025] The sensor bracket 33 in the ridge height detection device B will be described. 5 to 10, the sensor bracket 33 is made up of a plate-shaped mounting plate 331 attached to the slide rail 32 with its movable surface facing forward and backward, and a plate-shaped sensor fixing plate 35 attached to the lower part of the mounting plate 331 with its surface for mounting a sensor 36 facing left and right. The sensor bracket 33 is slidable horizontally left and right relative to the traveling direction by the slide rail 32. By attaching the sensor bracket 33 to the slide rail 32, the sensor 36 is movable in the width direction of the cover body G, which is the travel direction.

[0026] The sensor 36 in the ridge height detection device B will be described. A sensor 36 is attached to the sensor fixing plate 35 as shown in FIG. 5 and subsequent figures. The sensor 36 is capable of measuring the height from the underside of the sensor 36 to the ridge top surface U1 located directly below the sensor 36. In this embodiment of the invention, a photoelectric sensor is used. The photoelectric sensor is configured to be able to measure the distance to the target surface by projecting laser light toward the target surface and receiving the light reflected from the target surface. In this embodiment, the target surface is the ridge top surface U1. That is, the distance from the sensor 36 to the ridge top surface U1 can be measured by projecting light from the sensor 36 downward onto the ridge top surface U1 and receiving the laser light reflected from the ridge top surface U1. In this embodiment of the invention, the sensor 36 is capable of detecting the ridge height, and is fixed to the rear of the cover body G that covers the upper part of the cutting blade unit F having multiple cutting blades 23. Therefore, it is possible to know the state of the ridge U after it has been cut by the cutting blade unit F. Furthermore, the sensor 36 is provided close to the tail wheel mechanism H provided on the cover body G without contacting the tail wheel mechanism H. Therefore, it is possible to know the current state of the ridge U more accurately. Furthermore, since the relative height positional relationship between the sensor 36 and the cover body G and the relative positional relationship between the cover body G and the cutting blade unit F do not change, it is possible to directly measure the relative height between the lower end of the cutting blade unit F and the ridge top surface U1.

[0027] By integrating the sensor 36 with the cover body G, it is possible to directly measure the relative height between the cutting blade 23 and the ridge U. Although the sensor 36 can be installed on the tail wheel mechanism H (the tail wheel frame 45, the tail wheel arm 47, etc.), since a movable part is included between the tail wheel mechanism H and the cover body G, in order to grasp the relative height between the cutting blade 23 and the ridge U, it is necessary to accurately measure and calculate the positional relationship between the cover body G and the tail wheel mechanism H. That is, by integrating the sensor 36 with the cover body G, it is possible to configure the sensor 36 without increasing the number of measurement points. Although vibration of the cover body G is a concern, the cover body G is fixed to pipes (portions to which the fixing members 37 are attached) on the left and right sides of the rear end portion thereof. Therefore, the cover body G has a structure with a certain degree of strength.

[0028] The sensor 36 is movable on the slide rail 32 and is capable of detecting the ridge height. When the guide means 34E comes into contact with the ridge U, the sensor 36 moves along the longitudinal direction of the slide rail 32 so as to be positioned approximately at the center in the width direction of the ridge U. In other words, the sensor 36 can be positioned on the ridge upper surface U1 while moving left and right in the direction of travel by the slide rail 32, regardless of the relative positional relationship between the cover body G and the ridge U. A space is provided between the sensor 36 and the ridge U1 where no other components are placed. In other words, when the sensor continues to be positioned on the ridge top surface U1 while moving left and right, it is possible to prevent interference from other components that would make it impossible to measure. Also, because a space is provided below the non-contact type sensor 36 as in the embodiment where nothing is placed, it is possible to prevent malfunctions and erroneous measurements due to foreign matter scattered from the rear of the cover body G or the adhesion of such foreign matter, unlike sensors that physically contact the target object, such as arm-type sensors.

[0029] The type of the sensor 36 may be any type other than the photoelectric sensor shown as an example, as long as it can measure distance, and may be an optical type as in the embodiment, or a type using radio waves or ultrasonic waves. Also, other than the above, a type that measures distance by directly contacting the ridge U may be used as long as it can prevent malfunction and erroneous measurement due to foreign matter or the adhesion of such foreign matter. The sensor 36 is fixed in a vertical position relative to the cover body G and the cutting blade unit F. Therefore, by measuring the distance from the sensor 36 to the ridge top surface U1, it is possible to calculate the height from the lower end of the rotational area F1 of the cutting blade unit F to the ridge top surface U1. The sensor 36 is configured to be capable of outputting a measurement signal that is a measurement signal. The measurement signal can be transmitted to a control unit (not shown).

[0030] The control unit will now be described. The sensor 36 is connected to the control unit. The control unit can operate the lifting means 41 based on the measurement signal input from the sensor 36, and can automatically change the height of the cutting blade unit F from the ground by moving the ground contact means 51 of the tail wheel mechanism H up and down. The control unit can also be configured to display the measurement signal input from the sensor 36 on a display terminal (not shown) as the height from the ground, and can be configured to allow an operator (not shown) who recognizes the displayed value to manually operate the lifting means 41 to a desired height.

[0031] The first elastic body 332 in the ridge height detection device B will be described. The sensor bracket 33 is biased by a first elastic body 332. The first elastic body 332 constantly biases the sensor bracket 33 toward the center in the width direction of the cover body G. In the embodiment, the first elastic body 332 has two tension springs disposed on the left and right of the sensor bracket 33, and constantly biases the sensor bracket 33 toward the center in the width direction of the cover body G. There are no limitations on the number, biasing direction, or installation method of the first elastic bodies 332, so long as they achieve the purpose of constantly biasing the sensor bracket 33 toward the center in the width direction of the cover body G. The first elastic body 332 biases the sensor bracket 33 toward the center of the slide rail 32. In other words, the sensor 36 is constantly biased toward the center of the cover body G in the left-right width direction.

[0032] The first arm 34A in the ridge height detection device B shown in FIG. 2 and subsequent figures will be described. The first arm 34A is attached to the rear-facing portion of the support base 31 below the slide rail 32. The first arm 34A is a vertically long member in rear view and is U-shaped in plan view. The upper end of the first arm 34A is rotatably connected to the support base 31. A pair of first arms 34A are provided symmetrically with the left and right central portions of the support base 31 as the axis. 34AL is the left first arm and 34AR is the right first arm. The first arm 34A is attached to the support base 31, and is a pair of first arms 34A, namely, a left first arm 34AL and a right first arm 34AR, which are rotatably connected to the support base 31.

[0033] The second arm 34B in the ridge height detection device B will be described. The second arm 34B is connected to the first arm 34A. The second arm 34B is a rectangular plate member that is long in the left-right direction when viewed from behind, and the outer end of the second arm 34B in the width direction in the traveling direction is rotatably connected to the middle part of the first arm 34A. Similar to the first arm 34A, the second arm 34B also has a pair of left second arms 34BL and right second arms 34BR that are symmetrical on the left and right sides, with their inner ends in the width direction of the traveling direction rotatably connected to each other by a connecting member 38. The second arm 34B consists of a pair that is rotatably connected to the first arm 34A. In the embodiment, the connecting member 38 is formed of a bolt and a nut, and in this case, by not completely fastening, the second arm 34B can rotate around the connecting member 38. Besides being formed of a bolt and a nut, the connecting member 38 may be formed of a pin-shaped member, and there is no limitation on its configuration as long as it can rotatably connect the second arms 34B to each other.

[0034] The third arm 34C in the ridge height detection device B will be described. The third arm 34C is provided at the bottom of the support base 31. The third arm 34C is a member that is long in the vertical direction. The lower end of the third arm 34C is inserted into a rotation shaft provided at the bottom of the support base 31, and the third arm 34C is freely rotatable around this rotation shaft as a fulcrum. The middle part of the third arm 34C in the longitudinal direction is connected to the connecting member 38. In other words, the middle part of the third arm 34C is commonly connected to the inner end of the second arm 34B by the connecting member 38. The third arm 34C is rotatably connected to the support base 31 and is also connected to the sensor bracket 33 and the second arm 34B.

[0035] With the above configuration, for example, when the lower end of the left first arm 34AL of the pair of arms rotates to the left in the traveling direction, the upper end of the third arm 34C rotates to the left in the traveling direction via the left second arm 34BL of the pair of arms. Then, in response to the rotation of the third arm 34C, the lower end of the right first arm 34AR of the pair of arms rotates to the left in the traveling direction via the right second arm 34BR of the pair of arms. That is, the pair of first arms 34A rotate in the same direction by being connected to the second arm 34B and the third arm 34C. Even if the left and right rotation directions of the first arms 34A are different, they rotate in the same direction in a similar manner in conjunction with each other according to the above action.

[0036] The upper end portion of the third arm 34C will now be described. The upper end of the third arm 34C reaches the front of the mounting plate 331 of the sensor bracket 33. As shown in Figs. 5 to 10, a long hole 39 is provided at the upper end of the third arm 34C. A guide pin 391 protruding forward from the mounting plate 331 is positioned in this long hole 39. On the other hand, the upper end side of the third arm 34C swings left and right as the third arm 34C rotates about the lower part of the support base 31 as a fulcrum. Therefore, as the third arm 34C swings left and right, it pushes the sensor bracket 33 toward the left and right in the longitudinal direction of the slide rail 32 via the long hole 39 and the guide pin 391, thereby moving it horizontally left and right. A guide pin 391 in an elongated hole 39 provided in the third arm 34C changes its position relatively in accordance with the amount of swing of the third arm 34C, thereby allowing the sensor bracket 33 to move smoothly along the slide rail 32.

[0037] The guide arm 34D in the ridge height detection device B will be described. The guide arm 34D is connected to the first arm 34A. The guide arm 34D is a vertically long member, with its upper end connected to the lower end of the first arm 34A and provided so as to be rotatable left and right. The guide arms 34D are attached to the first arms 34A arranged on the left and right sides as a pair of left guide arms 34DL and right guide arms 34DR, provided symmetrically to each other. The lower end of the guide arm 34D can swing left and right in the traveling direction. The guide arm 34D is rotatably connected to the lower end of the first arm 34A, and has a guide means 34E that contacts the side surface of the ridge U. The guide arm 34D is provided with a rotation restricting portion J that allows the guide arm 34D to rotate within a determined rotation range relative to the first arm 34A.

[0038] The rotation restricting portion J will be described. A rotation restricting portion J is provided at the upper end of the guide arm 34D in a position close to the connection portion with the first arm 34A. The rotation restricting portion J is composed of an arc-shaped restricting hole J1 provided at the upper end of the guide arm 34D and a restricting pin J2 fixed to the lower end side of the first arm 34A. The restricting pin J2 is located in the restricting hole J1 and is provided so as to be relatively movable within the restricting hole J1. The guide arm 34D is freely rotatable within a range in which the restricting pin J2 can be located within the restricting hole J1. In other words, the rotation range of the guide arm 34D is limited by the rotation restricting portion J. In the illustration of FIG. 2, it is shown that the guide arm 34D and the guide means 34E can be rotated from the position indicated by the solid line to the position indicated by the two-dot chain line.

[0039] The second elastic body 333 in the ridge height detection device B will be described. A second elastic body 333 is disposed at the upper end of the guide arm 34D and at the middle of the first arm 34A. The second elastic body 333 biases the lower end side of the guide arm 34D inward in the width direction of the travel direction. In other words, it biases the lower end side of the guide arm 34D toward the center in the width direction of the ridge U. Also, in the embodiment, a tension spring is used as the second elastic body 333, but there are no limitations on the type of elastic body or the position where the elastic body is installed as long as the direction of biasing the guide arm 34D is the direction described above. The biasing force of the second elastic body 333 is configured to be greater than the biasing force of the first elastic body 332. This will be described later. The second elastic body 333 biases the guide arm 34D so as to constantly press against the side surface of the ridge U.

[0040] The guide means 34E in the ridge height detection device B will be described. Guide means 34E is attached to the lower end of the guide arm 34D. The guide means 34E is a member that contacts the ridge side surface U3, and is fixed to each of the guide arms 34D arranged on the left and right in a symmetrical shape. The guide means 34E is composed of left guide means 34EL and right guide means 34ER. Guide means 34E in contact with ridge U swings guide arm 34D, thereby swinging sensor bracket 33 via first arm 34A, second arm 34B, and third arm 34C. In other words, guide means 34E in contact with ridge side surface U3 is configured to be able to swing sensor 36 left and right in the traveling direction.

[0041] In the first embodiment, the guide means 34E shown in Fig. 2 and subsequent figures is configured as a sled, and is configured so as to be able to come into contact with the ridge side U3. The sled-shaped guide means 34E is inclined relative to the contact surface so as it moves downward from the contact surface with the ridge U and widens outward in the width direction. In addition, the front end of the sled-shaped guide means 34E is inclined relative to the contact surface so as it moves forward from the contact surface and widens outward in the width direction in the traveling direction. This configuration prevents the guide means 34E from being buried in the ridge U when it is advanced while in contact with the ridge side U3. The guide means 34E contacts both sides of the ridge U as shown in Fig. 2. In this embodiment, the guide means 34E is positioned so as to contact the shoulder portion U5 of the ridge. Since it is sufficient for the guide means 34E to detect the position of the ridge U by abutting the left and right positions of the ridge, it may also be positioned so as to contact the ridge side surface U3 below the shoulder portion U5.

[0042] Illustrated in Figures 9 and 10 is a second embodiment of the guide means 34E. The guide means 34E is not limited to a sled shape as shown in FIG. 2, FIG. 5 to FIG. 9. For example, as in the second embodiment of the guide means 34E shown in FIG. 9 and FIG. 10, the guide means 34E may be configured as a cylindrical, rotatable roller. In this case, the guide means 34E may be formed as a roller that is long in the axial direction so as to extend in the direction of the rotation axis and suppress the ground pressure. In this case, the guide means 34E moves while rolling on the ridge side U3 and the ridge shoulder U5, so that friction with the ridge U can be reduced. This embodiment is particularly effective when the ridge U is covered with a mulch film (not shown). In other words, the friction when pressing against the ridge is reduced, so the risk of damage to the mulch film is reduced and the subsequent recovery work is facilitated. Of course, the second embodiment can also be used for the ridge U where no mulch film is laid.

[0043] The function and effect of each part during operation will be explained. First, the agricultural work machine A is positioned above the upper surface U1 of the ridge. At this time, as shown in Fig. 2, the cover body G is positioned so that its left-right central portion is located above the left-right central portion of the ridge U. In other words, the left-right central portion of the cutting blade portion F is located above the left-right central portion of the ridge U. At this time, the sensor bracket 33 is urged toward the left-right central portion of the cover body G by the first elastic body 332, and the sensor 36 located in the left-right central portion of the cover body G can also be positioned above the left-right central portion of the ridge U.

[0044] The height of the agricultural work machine A is adjusted by raising and lowering the lifting device of the traveling body so that the cutting blade F located directly above the center of the ridge U can be at any desired height. In this embodiment of the present invention, the cutting blade F is positioned so that it contacts the ridge U or is located slightly above it. More specifically, in the case of ridges U covered with mulch film, the cutting blade F is positioned slightly above the ridges U covered with the mulch film so as not to crush the mulch film. In the case of ridges U not covered with mulch film, the cutting blade F is positioned at a height that does not damage the harvested crop underground, so that the cutting blade F comes into contact with the ridge top surface U1 or is positioned slightly above the ridge top surface U1.

[0045] After the height of the agricultural work machine A is roughly determined by the lifting device of the traveling body, the height is adjusted so that the ground contact means 51 of the tail wheel mechanism H is placed at the ridge bottom U2. By doing this, the height of the cutting blade F will not move below at least the height at which the ground contact means 51 of the tail wheel mechanism H touches the ground. After the adjustment, the tail wheel mechanism H is raised and lowered to move the main body of the agricultural work machine A up and down to adjust the cutting blade height. Also, by adjusting the tail wheel mechanism H during work, the ridge height, which is the relative distance between the cutting blade F and the ridge U, can be fine-tuned.

[0046] As the height of the agricultural work machine A is adjusted, the guide means 34E eventually comes into contact with the shoulder U5 of the ridge U from the side. In this embodiment of the invention, the cross-sectional shape of the ridge U is formed into a trapezoid, and the ridge side U3 is illustrated as inclining toward the center of the left-right width of the ridge U as it moves upward from the ridge bottom U2. As the height of the agricultural work machine A is gradually lowered, the guide means 34E is pushed outward in the width direction along the inclination of the side of the ridge U. In other words, the lower end of the guide arm 34D rotates outward in the width direction along the side of the ridge U.

[0047] The lower end side of the guide arm 34D is biased toward the center of the ridge U by the second elastic body 333. Therefore, in contrast to the above, when the height of the agricultural work machine A is raised with the guide means 34E in contact with the side surface of the ridge U, the guide arm 34D rotates toward the ridge side surface U3 until it is restricted by the rotation restricting part J. Therefore, even when the agricultural work machine A is raised or lowered relative to the ridge U, the guide means 34E can come into contact with the ridge side surface U3 until it is restricted by the rotation restricting portion J.

[0048] The movement of the agricultural work machine A will be described with reference to Figs. With the guide means 34E in contact with the ridge side U3, the cutting blade F is driven to rotate and move forward. The top of the ridge and the ridge base U2 are covered with vines growing from the harvested crop underground. The operator operating the traveling machine moves the traveling machine forward while predicting or estimating the vine-covered ridge U. Therefore, it is possible that the traveling machine and the agricultural work machine A may deviate relatively to the left or right in the direction of travel with respect to the ridge U. In the explanation, an example is shown in which the cover body G is shifted to the right in the direction of travel with respect to the ridge U, but if the cover body G is shifted to the left in the direction of travel with respect to the ridge U, the opposite operation will be performed and therefore this explanation will be omitted.

[0049] Fig. 7 shows a case where the cover body G is slightly deviated to the right in the direction of travel relative to the ridges U, and Fig. 8 shows a case where the cover body G is significantly deviated to the right in the direction of travel relative to the ridges U. Fig. 6 shows a state where the left-right center of the cover body G is not deviated at all from the left-right center of the ridges U.

[0050] The pressing side during operation will be described. When the agricultural work machine A deviates from the ridge U and the cover body G shifts relatively to the right side of the ridge U in the traveling direction, the ridge side U3 on the left side of the traveling direction or the left shoulder U5 of the ridge U presses the guide means 34E toward the left side of the traveling direction. The left guide arm 34DL arranged on the left side of the guide arm 34D tries to move relatively to the left side of the traveling direction with respect to the cover body G. In response to this, the lower end side of the first arm 34A also tries to move relatively to the left in the traveling direction with respect to the cover body G, and rotates about the support base 31 as a fulcrum. That is, the lower end side of the left first arm 34AL on the left side of the first arm 34A rotates so as to move relatively to the left with respect to the cover body G. At this time, the guide arm 34D is biased by the second elastic body 333, so that the guide means 34E continues to contact the ridge side U3 or the ridge shoulder U5.

[0051] By the rotation of the left first arm 34AL on the left side, the left second arm 34BL connected to the left first arm 34AL on the left side also moves to the left in the traveling direction. The upper end side of the third arm 34C connected to the second arm 34B rotates to the left in the traveling direction as shown in Fig. 7 which shows a case where the cover body is slightly displaced from the left-right center of the ridge, and Fig. 8 which shows a case where the cover body is significantly displaced from the left-right center of the ridge. In Figs. 7 and 8, 36A is a virtual line showing the position of the sensor, 36B is the amount of deviation of the position of the sensor 36 from the center position of the cover body G, and 36C is a virtual line showing the left-right center of the cover body G. That is, the long hole 39 at the upper end of the third arm 34C moves leftward in the traveling direction. The long hole 39 presses the guide pin 391 provided on the mounting plate 331 of the sensor bracket 33 leftward in the traveling direction, whereby the sensor bracket 33 moves leftward along the slide rail 32 relative to the cover body G. As a result, as shown in Figures 7 and 8, the sensor 36 mounted on the sensor bracket 33 moves leftward relative to the cover body G, but does not move relative to the ridge U, as can be seen by comparing with Figure 6. Alternatively, the sensor 36 moves leftward relative to the cover body G, but does not move significantly relative to the ridge U. The sensor 36 can always be positioned above the center of the left and right of the ridge U. In other words, the sensor 36 can remain positioned on the ridge top surface U1 regardless of the relative positional relationship of the cover body G to the ridge U in the width direction.

[0052] The non-pressing side during operation will be described. Of the pair of left and right second arms 34BL and 34BR, the third arm 34C is connected to the right second arm 34BR on the right side, which is the direction in which the machine is shifted. The right second arm 34BR on the right side also moves leftward in the traveling direction, like the left second arm 34BL on the left side, as shown in Figures 7 and 8. The right first arm 34AR on the right side connected to the right second arm 34BR on the right side rotates about the support base 31 side as a fulcrum so that the lower end side moves leftward in the traveling direction, similar to the left first arm 34AL on the left side.

[0053] Therefore, the right guide arm 34DR and the right guide means 34ER on the right side can move leftward in the traveling direction. As a result, as shown in Figures 7 and 8, the right guide means 34ER on the right side away from the ridge side surface U3 can move leftward in the traveling direction in the same way as the left guide means 34EL on the left side, and can be brought into contact with the right side surface of the ridge U. That is, during operation, the left and right guide means 34E can always come into contact with the ridge side surface U3 regardless of the direction in which the sensor 36 swings left and right.

[0054] For this reason, even if the cover body G and the cutting blade section F move alternately left and right or randomly left and right from the ridge center U4 as the traveling machine body advances in a zigzag pattern relative to the ridge U, the sensor 36 can immediately capture the ridge side surface U3 and move toward the ridge center U4 as shown in Figures 7 and 8. Therefore, the sensor 36 does not deviate significantly to the side from the ridge center U4, and can accurately measure the height of the ridge top surface U1.

[0055] The sensor 36, which is always located above the center U4 of the ridge, is connected to the control unit. The sensor 36 can accurately measure the height of the ridge U and output a measurement signal of the measured ridge height. Therefore, when the control unit automatically raises and lowers the tail wheel mechanism H, it can operate based on the measurement signal, which is information on the correct height of the ridge U, so that the tail wheel mechanism H can be raised and lowered with higher precision to adjust the height of the cutting blade 23.

[0056] Furthermore, even when the tail wheel mechanism H is raised and lowered manually, the control unit displays the ridge height on the display terminal based on the measurement signal, which is information on the correct height of the ridge U, so the worker can operate the lifting means 41 to raise and lower the tail wheel mechanism H based on the highly accurate and reliable display. The first arm 34A, the second arm 34B, and the guide arm 34D on the side moving away from the ridge side U3 so as to move from the ridge center U4 toward the outside in the width direction also swing in conjunction with the first arm 34A, the second arm 34B, and the guide arm 34D on the side approaching the ridge center U4 so as to move from the ridge side U3 toward the ridge center U4.

[0057] In this embodiment of the present invention, the biasing force of the second elastic body 333 is greater than that of the first elastic body 332. By providing a difference in the biasing forces, when the guide means 34E is pressed from the ridge side surface U3, the sensor bracket 33 can quickly swing against the biasing force of the first elastic body 332 without causing the guide arm 34D to rotate due to the biasing force of the second elastic body 333. Therefore, when the cover body G is shifted relatively in the left-right direction with respect to the ridge U, the sensor 36 can be quickly moved left-right with respect to the cover body G and positioned above the center of the ridge U.

[0058] The second elastic body 333 is effective when the sensor 36 reaches the limit of its left-right movement range but the cover body G attempts to deviate further in the left-right direction relative to the ridge U. Assuming that the guide arm 34D is fixed to the first arm 34A, when the cover body G deviates from the ridge U beyond the limit of the left-right movement range of the sensor 36, an abnormal state may occur in which the guide arm 34D and the guide means 34E pierce the ridge center U4 from the ridge side U3.

[0059] However, in this embodiment of the present invention, the guide arm 34D is freely rotatable relative to the first arm 34A and is biased toward the ridge U by the second elastic body 333, so that even if the above-mentioned abnormal condition occurs, the guide means 34E rotates while maintaining contact with the ridge U, thereby preventing damage to the ridge U. As the abnormal state is resolved, the guide arm 34D rotates so that the longitudinal direction of the guide arm 34D faces the vertical direction. After the abnormal state is resolved, the sensor 36 is again biased by the first elastic body 332, and the guide means 34E comes into contact with the ridge side surface U3 and moves left and right.

[0060] Therefore, by making the biasing force of the second elastic body 333 stronger than that of the first elastic body 332, it is possible to prevent damage to the ridges U without impeding the left-right movement of the sensor 36 relative to the cover body G. Furthermore, when the sensor 36 returns from the abnormal state to the normal state as shown in Figures 6 to 8, the sensor 36 can start moving left-right again as usual. Furthermore, it is assumed that the second elastic body 333 is such that the cover body G is not shifted left or right relative to the ridge U, and the cover body G approaches the ridge U. In this case, the sensor 36 does not move, and the left and right guide means 34E are pressed to spread along the slope of the ridge side surface U3 while resisting the biasing force of the second elastic body 333. When the cover body G is released from its proximity to the ridges U, the guide means 34E returns to its original position while in contact with the ridges U and is biased by the second elastic body 333. Even in a situation where the guide means 34E pierces the ridges U from above, it can return to its original position without damaging the ridges U. In addition, since the guide means 34E maintains a constant state of contact with the ridges U, immediate action can be taken if the cover body G and the ridges U are misaligned to the left or right.

[0061] The configuration of the tail wheel mechanism H and the agricultural machine A operated using the ridge height detection device B of the present invention is not limited to the form of the embodiment. Since the ridge height can be measured with high accuracy as the machine progresses, it is expected to be useful for the agricultural machine A working on the ridges U. In the embodiment described above, the first arm 34A, the second arm 34B, the guide arm 34D, and the guide means 34E are provided in pairs on the left and right sides, respectively. However, even if the first arm 34A, the second arm 34B, the guide arm 34D, and the guide means 34E are arranged on only one side, the sensor 36 can still follow the ridge top surface U1. When left-right misalignment occurs between the cover body G and the ridge U, the immediate response performance is slightly inferior to when a pair is provided, but the configuration of the ridge height detection device B can be simplified. Therefore, the number of processes related to manufacturing and machine maintenance can be reduced. Furthermore, the shape of the ridge U to which the ridge height detection device B of the present invention can be applied is not limited to that shown in the figure, and the shapes of each part of the ridge height detection device B can be appropriately changed depending on the shape of the ridge U.

[0062] The tail wheel mechanism H will now be further explained. The first link 43 will be described. The first link 43 is rotatable at a left-right intermediate portion of the upper portion of the cover body G in the width direction. A first link 43 is rotatably provided at the rear of the cover body G near the left-right center of the cover body G. The first link 43 is a member that is long in the front-to-rear direction, and its front end is rotatably provided relative to the cover body G. In this embodiment, two first links 43 are provided with a gap between them near the left-right center of the width of the cover body G. The first links 43 are positioned so that there is no ridge U below them. In other words, the first links 43 are positioned so that they are located on the ridge bottom U2. The rotation fulcrum of the first link 43 relative to the cover body G is positioned above the rear end of the cover body G.

[0063] The second link 44 will now be described. The second link 44 is provided at the lower part of the cover body G at the side of the cover body G so as to be rotatable. The second links 44 are rotatably provided at the left and right ends of the cover body G, at the rear of the cover body G. The second links 44 are members that are long in the front-to-rear direction, and their front ends are rotatably provided on side plates G1 located at the left and right ends of the cover body G. It can also be said that the second links 44 are located outside the working width of the cutting blade unit F. In the embodiment, two second links 44 are located at both outer ends of the cover body G. The longitudinal length of the second links 44 is set to be the same as that of the first links 43.

[0064] The tail wheel frame 45 will now be described. A tail wheel frame 45 is provided to connect the rear end of the first link 43 and the rear end of the second link 44. The tail wheel frame 45 has a frame that is long in the left-right direction, a first link connecting portion 431 that connects the first link 43, and a second link connecting portion 441 that connects the second link 44. In the embodiment, the first link connection portions 431 are provided at two locations near the left and right central portions of the frame to connect the respective rear ends of the two first links 43, and the second link connection portions 441 are provided at both left and right ends of the frame to connect the respective rear ends of the two second links 44.

[0065] The first link 43 and the second link 44 are connected to the cover body G and the tail wheel frame 45 to form parallel links in a side view. When the first link 43 and the second link 44 move up and down with the cover body G as a fulcrum, the tail wheel frame 45 located at the rear end moves up and down relative to the cover body G. As described above, the front-to-rear lengths, which are the lengths in the longitudinal direction of the first link 43 and the second link 44, are set to be the same, so when the tail wheel frame 45 moves up and down, it moves up and down without tilting, while maintaining an angle relative to the cover body G.

[0066] The advantages of the arrangement of the tail wheel mechanism H will now be explained. The first link 43, the second link 44 and the tail wheel frame 45, which move up and down, are cover body G and are not located below the lower end of the cover main body that covers the cutting blade F. Stems and vines cut or severed by the cutting blade F may fly backward from the lower end of the cover main body that does not cover the blade. However, the first link 43, the second link 44, and the tail wheel frame 45, which move up and down, are located above the rear lower end G3 of the cover body at any position, so that scattered stems and vines do not adhere to them. Fig. 11 shows the state in which the tail wheel frame 45 is located at the uppermost position relative to the cover body G, and Fig. 12 shows the state in which the tail wheel frame 45 is located at the lowermost position relative to the cover body G. As shown in the figures, the first link 43, the second link 44, and the tail wheel frame 45 rotate and move above the rear lower end G3 of the cover body. Moreover, the second link 44 is disposed further outboard than the working width of the cutting blade unit F, further reducing the possibility of scattered stems and vines adhering to them. Therefore, the first link 43, the second link 44, and the tail wheel frame 45 are disposed in a configuration that can prevent foreign objects from adhering to them, so that the operator can be prevented from removing foreign objects from the first link 43, the second link 44, and the tail wheel frame 45. Also, although the first link 43 has been described as being disposed on the cover body G, it can also be rotatably mounted on the side plate G1, similar to the second link 44. In this case, the first link 43 can further reduce the possibility of scattered stems and vines attaching to it.

[0067] The holder 46 of the tail wheel frame 45 of the tail wheel mechanism H will be described. A holder 46 is provided on the tail wheel frame 45. The holder 46 can hold and fix a tail wheel arm 47, which will be described later. In this embodiment, the holder 46 is made of a square pipe with its elongated direction facing up and down.

[0068] The grounding means 51 includes a holder 46 fixed to the rear of the tail wheel frame 45. The tail wheel frame 45 is provided parallel to the cover body G on the left and right in the traveling direction, and connects the first link 43 and the second link 44. An explanation will be given of the tail wheel arm 47 of the tail wheel mechanism H. The tail wheel arm 47 of the tail wheel mechanism H is provided so as to be vertically movable relative to the holder 46 and so as to be able to be fixed in position relative to the holder 46. The tail wheel arm 47 is inserted into the holder 46. The tail wheel arm 47 is a vertically long member, and has multiple adjustment holes at its upper end. The adjustment holes can be aligned with the fixing holes 461 that penetrate the holder 46, and a fixing member 462 made of a pin-shaped member can be inserted into them. The tail wheel arm 47 and the holder 46 are fixed together by inserting the fixing member 462. Since multiple adjustment holes are provided in the vertical direction, the lower end position of the tail wheel arm 47 relative to the holder 46 can be selectively adjusted by selecting an adjustment hole at any position and inserting the fixing member 462 into the fixing hole 461. The tail wheel arm 47 can be adjusted in stages from the position represented by the solid line in FIG. 1 to the position represented by the two-dot chain line together with the grounding means 51 described later. Although it is difficult to change the position adjustment of the tail wheel arm 47 relative to the holder 46 during work, the tail wheel arm 47 can be moved up and down by the lifting means 41 during work. Also, as in this embodiment, the position of the tail wheel arm 47 can be adjusted relative to the holder 46, but it is also possible to omit the holder 46 and attach the tail wheel arm 47 directly to the tail wheel frame 45. In this case, the position adjustment between the tail wheel arm 47 and the holder 46 is omitted, but the configuration of the tail wheel mechanism H can be simplified, making it easier to manufacture and to inspect during operation.

[0069] Since the tail wheel frame 45 of the tail wheel mechanism H is configured to be able to rise and fall while maintaining a relative angle with respect to the cover body G, the tail wheel arm 47 is also able to rise and fall while maintaining a relative angle with respect to the cover body G. Therefore, the lower end of the tail wheel arm 47 does not move back and forth relative to the cover body G when it is raised and lowered, so the overall length of the agricultural work machine A does not change significantly. In other words, even when the tail wheel arm 47 moves up and down, the overall length of the agricultural work machine A can be almost maintained, so a worker aboard the traveling body can work without feeling a change in the sense of distance to the rear end of the agricultural work machine A.

[0070] The lifting means 41, which is the extension and contraction means of the tail wheel mechanism H, connects the upper part of the cover body G to the first link 43, and moves the tail wheel frame 45, the tail wheel arm 47, and the ground contact means 51 up and down by extending and contracting. The grounding means 51 of the tail wheel mechanism H will be described. A ground contact means 51 is provided at the lower end of the tail wheel arm 47. In this embodiment, the ground contact means 51 is a wheel, and while the wheel is in contact with and rolling on the ground at the ridge bottom U2, the tail wheel frame 45 is moved up and down by the lifting means 41, which is an extension means, so that the cutting height of the cutting blade portion F can be adjusted while working. The wheels, which are the ground contact means 51 shown in this embodiment, are provided on the tail wheel arm 47 so as not to be rotatable in the horizontal direction. Ground contact means 51 consisting of wheels provided on the tail wheel mechanism H is brought into contact with the ground, and the ground contact means 51 rolls as the machine moves forward. The ground contact means 51 can move up and down relative to the cover body G by the lifting means 41, which is an extension and contraction means. In other words, by moving the tail wheel frame 45 up and down with the ground contact means 51 in contact with the ground, the cutting blade section F moves up and down. In other words, the cutting height can be adjusted by the ground contact means 51.

[0071] The ground contact means 51 moves forward while in contact with the ridge bottom U2, thereby making it possible to maintain a constant mowing height, which is the height of the cover body G and the cutting blade F from the ridge bottom U2. In addition, the mowing height can be changed by moving the tail wheel arm 47 up and down. The ground contact means 51 is formed of wheels and is rotatably mounted on a horizontal axis at the lower end of the tail wheel arm 47. The wheels touch the ground on the ridge bottom U2 and move forward while rolling on the ridge bottom U2, allowing the agricultural work machine A located on the ridge U to move smoothly. The wheels may be made of any material, such as rubber, resin, or metal, and may be made of a composite of these materials. In the embodiment, the ground contact means 51 is formed of metal wheels. In the embodiment, the ground contact means 51 located at the ridge bottom U2 is located slightly inward in the vehicle width direction with respect to the cover body G from the side plate G1.

[0072] In the first embodiment of the present invention, the ground contact means 51 is configured with wheels, but as in the fourth embodiment shown in Fig. 14, the ground contact means 51 may be sled-shaped. In this case, the configurations of the ground contact means 51 and the lower end of the tail wheel arm 47 can be significantly simplified, thereby reducing the workload associated with maintenance.

[0073] The scraper 52 of the tail wheel mechanism H will now be described. The ground contact means 51 in the first embodiment comprises a scraper 52 arranged adjacent to the wheel. The grounding means 51 may have a scraper 52. The scraper 52 scrapes off the soil, stems, and vines adhering to the grounding portion of the wheel, which is the grounding means 51, so that the grounding means 51 can be grounded in an appropriate state. In other words, the rotational diameter of the wheel does not increase due to the adhesion of soil, stems, and vines, so the mowing height can be maintained at an appropriate height.

[0074] The lifting means 41 will now be described. Lifting means 41 is provided to lift and lower the grounding means 51. In this embodiment of the invention, a cylinder, which is an expandable means, is used as the lifting means 41. One end of the cylinder is connected to the cover body G, and the other end, which is a rod side, is connected to a connecting member 42 fixed to a first link 43. The extension and contraction of the cylinder causes the rear end side of the first link 43 to move up and down relative to the cover body G via the connecting member 42. As a result, the tail wheel frame 45 connected to the first link 43 also moves up and down, and the ground contact means 51 moves up and down relative to the cover body G. Since the ground contact means 51 can be raised and lowered by the cylinder, the operator can easily adjust the mowing height.

[0075] The lower end of the connecting member 42 is fixed by a long member 421 such as a square pipe so as to be connected to the two first links 43. In other words, the thrust of the cylinder can be distributed to the two first links 43, so that the tail wheel arm 47 can move up and down smoothly without being subjected to an unbalanced load.

[0076] A third embodiment, which is another example of the lifting means 41 of the tail wheel mechanism H shown in FIG. 13, will be described. The lifting means 41 for lifting and lowering the grounding means 51 is not limited to a cylinder. As shown in FIG. 13, instead of a cylinder, it is also possible to move the grounding means 51 up and down by rotating a rod 411 having a thread. One end of the rod 411 is provided on the cover so as to rotatably hold the handle 412, and a male thread is formed on the other end. A female thread is provided on the upper part of the connecting member 42, and the other end of the rod 411 is inserted into the female thread. In this state, by rotating the rod 411 in either direction using the handle 412, the grounding means 51 can be lifted and lowered. By configuring the lifting means 41 with the rod 411, the lifting means 41 can be made extremely simple.

[0077] A fifth embodiment shown in FIG. 15, which is another example of the grounding means 51, will be described. It has been stated that the ground contact means 51 in the first embodiment of the present invention is configured with wheels. The wheels are configured so as not to rotate horizontally relative to the tail wheel arm 47, but as shown in the fifth embodiment, they can be configured so as to be freely rotatable horizontally. In this case, if the ground contact means 51 is in a situation where it meanders in the width direction of the traveling direction relative to the ground on which it is in contact, the wheels will rotate horizontally in response to the meandering while touching the ground and rolling, allowing the tail wheel mechanism H to move more smoothly relative to the ground. As a result, excessive load is not placed on the tail wheel mechanism H in the width direction, and damage to the tail wheel mechanism H including the ground contact means 51 can be reduced.

[0078] The agricultural work machine A according to the embodiment of the present invention crushes the stalks and vines of sweet potato plants growing in the ridges U. If mulch film has been laid on the ridges U, the mulch film is removed and the potatoes are dug up. For this reason, the stalks and vines of sweet potato plants growing in the ridges U need to be cut short, right up to the vines. If the sensor 36 is lower than the apex U4 of the ridge U, the measured value will be inaccurate. For example, if the sensor 36 is located at the shoulder U5 of the ridge or at the top of the side U3 of the ridge, the relative height between the cover body G and the ridge top surface U1, which is used to measure the height of the ridge U, cannot be accurately measured. Therefore, it is important that the sensor 36 is located above the apex U4 of the ridge U or above a position near the apex U4. The ridge height detection device B of the present invention allows the sensor 36 to be located above the apex U4 of the ridge U. In addition, when cutting the vines and stems of sweet potatoes with the agricultural machine A, vines and stems grow thickly on the ridge U and the ridge bottom U2 in front of the cover body G, and if the sensor 36 is placed in front of the cover body G, accurate measurement will not be possible. Therefore, the sensor 36 needs to be brought to the rear of the agricultural machine A, since the measurement will be inaccurate unless the stalks and vines of sweet potatoes are cut. [Explanation of symbols]

[0079] 23 cutting blade 31 Support Base 41 Telescopic means (lifting means) 43 First link 44 Second Link 51 Grounding means F Cutting blade part G Cover body H Tail wheel mechanism

Claims

1. A tail wheel mechanism provided on a cover body that covers an upper portion of a cutting blade unit having a plurality of cutting blades, a first link that is rotatable at a left-right intermediate portion of an upper portion of the cover body; a second link provided rotatably on a side of the cover body at a lower portion of the cover body; a tail wheel frame provided on the left and right sides of the traveling direction in parallel with the cover body and connecting the first link and the second link; an extension / contraction means for connecting an upper portion of the cover body to the first link and extending / contracting to move the tail wheel frame up and down; a grounding means for fixing an upper part of the grounding means to the tail wheel frame and grounding a lower part of the ground to adjust the cutting height of the cutting blade by the extending and contracting means; A tail wheel mechanism comprising:

2. The grounding means includes a holder fixed to the tail wheel frame; an arm that is movable in a vertical direction relative to the holder and is provided so that its position can be fixed relative to the holder; a wheel rotatably provided at a lower end of the arm and capable of rolling when in contact with the ground; 2. The tail wheel mechanism according to claim 1, further comprising:

3. The grounding means includes a scraper disposed adjacent to the wheel; 3. The tail wheel mechanism according to claim 2, further comprising:

4. The grounding means is provided so as not to be rotatable in the horizontal direction.

3. A tail wheel mechanism as claimed in claim 1 or 2.

5. The grounding means is provided so as to be rotatable in a horizontal direction.

3. A tail wheel mechanism as claimed in claim 1 or 2.

6. A tail wheel mechanism provided on a cover body that covers an upper portion of a cutting blade unit having a plurality of cutting blades, a first link that is rotatable at a left-right intermediate portion of an upper portion of the cover body; a second link provided rotatably on a side of the cover body at a lower portion of the cover body; a tail wheel frame provided on the left and right sides of the traveling direction in parallel with the cover body and connecting the first link and the second link; an extension / contraction means for connecting an upper portion of the cover body to the first link and extending / contracting to move the tail wheel frame up and down; a grounding means for fixing an upper part of the grounding means to the tail wheel frame and grounding a lower part of the ground to adjust the cutting height of the cutting blade by the extending and contracting means; An agricultural machine having a tail wheel mechanism, comprising:

Images