Working machine

Abstract

To make an intermediate frame posture suitable for connection between an intermediate frame and a blade housing when the blade housing is mounted on a machine body.SOLUTION: The working machine includes the front coupling part 50C coupled to one end of the front link unit FL, the rear coupling part 6B coupled to one end of the rear link unit RL, the blade housing 40 coupled to the other end of the front link unit FL, the middle frame MF coupled to the other end of the rear link unit RL, the guide member provided on the blade housing 40, the guided member provided on the middle frame MF, and the posture holding link 62 that connects the rear link unit RL and the middle frame MF.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work machine capable of mounting a mower unit between the front and rear wheels below the machine body. [Background technology]

[0002] In the brush cutter described in Patent Document 1, an engaging portion provided on an intermediate structure connected to a lifting link mechanism attached to the machine body and an engaged portion provided on the mower deck come close to each other as the machine body moves forward and backward (for example, when the machine body moves over the mower deck). The machine is stopped when the engaging portion and the engaged portion are in such a close proximity state. When the operator gets off the machine and swings an operating lever located on the side of the mower deck, the connection between the machine body and the mower deck is locked by the locking mechanism, and the connection of the blade power transmission mechanism is also completed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-169507 Summary of the Invention [Problem to be solved by the invention]

[0004] In the brush cutter according to Patent Document 1, when the blade housing, which is the mower deck, is attached to the machine body, the positional relationship between the engaging part and the engaged part required for connecting and locking the intermediate frame, which is the intermediate structure, to the blade housing is prone to misalignment due to factors such as shaking of the lifting link mechanism.

[0005] An object of the present invention is to ensure that when a blade housing is attached to the aircraft body via an intermediate frame provided on a lifting link mechanism, the intermediate frame posture is suitable for connecting the intermediate frame and the blade housing. [Means for solving the problem]

[0006] A working machine according to the present invention includes a lifting link mechanism capable of mounting a mower unit between the front and rear wheels below a machine body, the lifting link mechanism comprising a front link unit and a rear link unit spaced apart in the fore-and-aft direction of the machine body, a front connecting part mounted on the machine body and connecting to one end of the front link unit, a rear connecting part mounted on the machine body and connecting to one end of the rear link unit, a blade housing connected to the other end of the front link unit, an intermediate frame connected to the other end of the rear link unit, a guide member mounted on the blade housing, a guided member mounted on the intermediate frame, and an attitude maintaining link connecting the rear link unit and the intermediate frame, the attitude maintaining link maintaining the intermediate frame in a proper attitude that allows the guide member and the guided member to be aligned. Note that by mounting a mower unit on the working machine, the working machine functions as a brush cutter, and by detaching the mower unit from the brush cutter, the brush cutter functions as a working machine, and therefore the subject of the present invention is a working machine and a brush cutter.

[0007] With this configuration, the swing angle of the rear link unit that constitutes the lifting link mechanism is restricted by the posture maintaining link, and as a result, the posture of the intermediate frame is maintained in a preset proper posture. This proper posture allows the guide members provided on the blade housing and the guided members provided on the intermediate frame to be properly aligned, and through this alignment, the intermediate frame and the blade housing are in a posture suitable for connection.

[0008] The present invention proposes that the posture maintaining link is a bending link that is provided between the rear link unit and the intermediate frame, and that the bending angle of the posture maintaining link is set to create the proper posture. In other words, the posture maintaining link is designed in relation to the structure of the intermediate frame so that it does not open beyond a predetermined bending angle (maximum bending angle), and the proper posture is created at this maximum bending angle. The bending link is preferably composed of two links that are swingably connected. By employing such a simple structure of the bending link, the posture of the intermediate frame can be maintained in the proper posture.

[0009] The present invention proposes that the intermediate frame is introduced into a predetermined position relative to the blade housing by alignment caused by the relative movement of the guiding member and the guided member, and the intermediate frame and the blade housing are automatically locked at the predetermined position. In this configuration, the steady relative movement (displacement) of the guiding member and the guided member is used in the automatic locking process between the intermediate frame and the blade housing, enabling accurate and stable automatic locking between the intermediate frame and the blade housing.

[0010] In the initial stage of engagement and guiding between a guiding member and a guided member, spatial positional errors may occur between the guiding member and the guided member, so it is preferable to provide a large margin for the engagement and guiding. In the final stage of engagement and guiding, accurate engagement and guiding is required by eliminating any gap between the guiding member and the guided member. For this reason, the present invention proposes that the guided member be a guided pin, that the guiding member is formed with a guide groove that guides the guided pin to the predetermined position, and that the guide groove comprises an inclined guide surface region whose groove width decreases from the opening toward the terminal end, and a linear guide surface region whose groove width corresponds to the lateral width of the guided pin.

[0011] The intermediate frame and the blade housing are automatically locked by relative movement (displacement) between them due to the guiding member and the guided member, and it is preferable that the mower-side power transmission mechanism and the machine-side power transmission mechanism are coupled at this time. Therefore, the present invention proposes providing a power coupling unit that couples the input shaft of the mower-side power transmission mechanism, which transmits engine power to the blades provided in the blade housing, to the machine-side power transmission mechanism, which supplies power to the mower-side power transmission mechanism. The power coupling unit is fixed to the underside of a cover plate attached to the intermediate frame as a cross member of the intermediate frame, and the input shaft (25b) is coupled to the power coupling unit by the relative movement. With this configuration, because the power coupling unit is fixed to the underside of the cover plate, damage to the power coupling unit due to external impact (for example, impact when a vehicle wheel runs over the mower unit) can be suppressed. [Brief explanation of the drawings]

[0012] [Figure 1] 10 is a schematic diagram showing a transition from a state before the mower unit is attached to the work machine to a state after the mower unit is attached to the work machine. FIG. [Figure 2] FIG. 2 is a side view of a work machine equipped with a mower unit. [Figure 3] FIG. 10 is a side view showing the connection between the front link unit and the aircraft body, and the connection between the front link unit and the blade housing. [Figure 4] FIG. 10 is a plan view of the blade housing coupled with the intermediate frame. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 10 is a perspective view of the blade housing before being connected to the front frame unit. [Figure 8] FIG. 10 is a side view of the front frame unit connected to the blade housing before it is connected to the airframe. [Figure 9]FIG. 10 is a side view showing the initial stage of the front frame unit connected to the blade housing being connected to the airframe. [Figure 10] FIG. 10 is a side view of an intermediate stage in which the front frame unit connected to the blade housing is connected to the fuselage. [Figure 11] FIG. 10 is a side view showing the final stage of the front frame unit connected to the blade housing being connected to the airframe. [Figure 12] FIG. 10 is a side view showing the intermediate frame and the blade housing just before they are locked together. [Figure 13] FIG. 10 is a side view of the intermediate frame approaching the blade housing. [Figure 14] FIG. 10 is a plan view of the intermediate frame approaching the blade housing. [Figure 15] FIG. 2 is an exploded perspective view of a rear link unit and an intermediate frame. [Figure 16] FIG. 10 is a side view showing the intermediate frame and the blade housing just before they are locked together. [Figure 17] FIG. 10 is a front view showing the left and right locking mechanisms and the double locking mechanism before locking. [Figure 18] 10A and 10B are side views illustrating the operation of the lock mechanism and the double lock mechanism. [Figure 19] 10A and 10B are side views illustrating the operation of the lock mechanism and the double lock mechanism. [Figure 20] 10A and 10B are side views illustrating the operation of the lock mechanism and the double lock mechanism. [Figure 21] FIG. 10 is a front view showing the left and right locking mechanisms and the double locking mechanism after being locked. [Figure 22] 5 is a perspective view showing another embodiment of the connecting plate shown in FIG. 4. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this specification, unless otherwise specified, "front" means forward in the longitudinal direction (traveling direction) of the aircraft, and "rear" means rearward in the longitudinal direction (traveling direction) of the aircraft. Also, left-right or lateral direction means the transverse direction (width direction) of the aircraft that is perpendicular to the forward direction of the aircraft. "Up" or "down" refers to the positional relationship in the vertical direction (perpendicular direction) of the aircraft, and indicates the relationship in terms of height above ground.

[0014] An embodiment of a work machine according to the present invention will be described below. First, an outline of the installation process for installing the mower unit 4 on this work machine will be described using Figure 1. In this installation process, the work machine before installation drives over the mower unit 4 placed on the ground, and the mower unit 4 is automatically installed between the front wheels 2a and rear wheels 2b in the area below the main frame 10 of the work machine. By installing the mower unit 4 on the work machine, the work machine functions as a brush cutter, and by detaching the mower unit 4 from the brush cutter, the brush cutter functions as a work machine. In this specification, unless a particular distinction is required, the main frame 10 or the basic configuration of the work machine will be referred to as the machine body.

[0015] To enable this installation process, a rear link unit RL is provided, one end of which is connected to the rear connecting portion 6B of the main frame 10. The other end of the rear link unit RL is connected to the intermediate frame MF. The intermediate frame MF is suspended by the rear link unit RL. The intermediate frame MF is provided with a power connection unit 25 at the tip of a machine body power transmission mechanism 25A that transmits rotational power (engine power) from the engine E to the mower unit 4. The intermediate frame MF is also provided with an engagement unit 7A for connecting to the mower unit 4.

[0016] A mower-side connecting unit 5B is connected to the blade housing 40 of the mower unit 4. Furthermore, the blade housing 40 is provided with an engaged unit 7B that can engage with the engaging unit 7A of the intermediate frame MF. During the installation process, the machine-side power transmission mechanism 25A is connected to the input shaft 25b of the mower-side power transmission mechanism 25B via the power connecting unit 25 so that power can be transmitted, and the engaging unit 7A of the intermediate frame MF is connected to the engaged unit 7B of the blade housing 40. Furthermore, at this time, the machine-side connecting body 50C provided at one end of the front link unit FL is connected to the machine-side connecting unit 5C, which is a front connecting portion provided on the main frame 10.

[0017] The front link unit FL and the rear link unit RL constitute a lifting link mechanism 3. When the link of the lifting link mechanism 3 is displaced, the intermediate frame MF and the blade housing 40 connected to the intermediate frame MF are displaced up and down relative to the ground.

[0018] One embodiment of this work machine is shown in Figure 2. This work machine is a multi-purpose tractor with a mower unit 4 detachably mounted between the front wheels 2a and rear wheels 2b. Therefore, this work machine can also be used as a regular tractor by removing the mower unit 4. A water-cooled engine E covered by a hood 11 is mounted in the front half of a main frame 10, and a driver's seat 12 is located in the rear half of the main frame 10. The front wheels 2a are steered wheels operated by a steering wheel 13 and are also drive wheels. Since this work machine is a four-wheel drive vehicle, the rear wheels 2b are also drive wheels. A transmission case 14 is provided in the rear half of the main frame 10.

[0019] Figures 3 and 4 show the mower unit 4 connected to the front link unit FL and the intermediate frame MF already connected to the rear link unit RL. Figure 5 shows the intermediate frame MF connected to the rear link unit RL, and Figure 6 shows the link unit RL and the intermediate frame MF exploded. Figure 7 shows the blade housing 40 that constitutes the mower unit 4. Figures 8, 9, 10, and 11 show the process of connecting the front link unit FL connected to the blade housing 40 to the machine body connecting unit 5C.

[0020] As shown in FIG. 4, the mower unit 4 includes a blade housing 40 that covers from above the blades BL (see FIG. 12), which rotate using power from the mower-side power transmission mechanism 25B. In this embodiment, three blades BL are arranged side by side in the transverse direction of the machine body in a plan view. The blade housing 40 has a top plate 41 and side plates 42 that extend downward from the periphery of the top plate 41. The mower-side power transmission mechanism 25B, which includes the input shaft 25b and the power distribution mechanism 25c, is provided on top of the top plate 41 of the blade housing 40. A grass clippings conveying path is formed inside the blade housing 40, and grass clippings are discharged from the right end of the blade housing 40.

[0021] As shown in Figure 7, a pair of left and right climbing covers 43 are provided on the top plate 41 to match the tread width of the front and rear wheels 2a and 2b, respectively, so that the work machine can climb over the blade housing 40 (mower unit 4) placed on the ground when climbing over it. These climbing covers protect the components of the mower unit 4 when the front wheels 2a climb over them. A guide rod 43a is provided on the top surface of the left climbing cover 43. In addition, a pair of left and right climbing steps 44 are provided on the side plates 42 (front side plates), to match the tread width of the front and rear wheels 2a and 2b.

[0022] Regarding the connection of the intermediate frame MF to the blade housing 40, an engaged unit 7B that connects with the engaging unit 7A of the intermediate frame MF and a guide member 9B for guiding the intermediate frame MF to an appropriate position relative to the blade housing 40 are provided on the top plate 41. Furthermore, a mower side connecting unit 5B that connects with the front link unit FL is provided on the side plate 42 (front side plate).

[0023] As shown in FIG. 7, the guide member 9B is composed of a pair of left and right angle brackets 91. The angle bracket 91 is composed of a front leg plate 91a, a rear leg plate 91b, and an upper plate 91c connecting the upper ends of the front leg plate 91a and the rear leg plate 91b. A guide groove 92 is formed from the upper region of the rear leg plate 91b to most of the upper plate 91c. A guided pin 90 (see FIG. 6), which is a guided member 9A of the intermediate frame MF, is guided along this guide groove 92. As shown in FIG. 7, a three-dimensional opening 92a for receiving the guided pin 90 is formed in the rear region of the guide groove 92 and has a large area to allow the guided pin 90 to easily enter. The guide groove 92 further includes an inclined guide surface region 92b whose groove width decreases from the three-dimensional opening 92a toward the groove end, and a linear guide surface region 92c whose groove width substantially matches the pin width of the guided pin 90 (see FIG. 14). That is, the guide groove 92 includes a three-dimensional opening 92a, an inclined guide surface region 92b, and a linear guide surface region 92c.

[0024] As shown in FIG. 7 , the engaged unit 7B, which connects the intermediate frame MF to the blade housing 40, is composed of a pair of left and right base brackets 95 and a pair of left and right vertical brackets 96. Bearing holes are provided in the vertical webs on both sides of the base bracket 95, and a lock rod 97 is inserted into these bearing holes. A gap is provided between the lock rod 97 and the top plate 41. This lock rod 97 is used to lock the intermediate frame MF, as described below. The base bracket 95 is fixed to the top plate 41 of the blade housing 40, and the vertical bracket 96 is fixed to a horizontal plate portion of the base bracket 95. The vertical bracket 96 also has a plate-shaped anti-lateral sway member 96a bent rearward and outward. Furthermore, a pressing portion 98, which will be described in detail later, is also fixed to the horizontal plate portion of the base bracket 95.

[0025] Next, the rear link unit RL and the intermediate frame MF will be described with reference to FIGS. 5 and 6. The rear link unit RL and the intermediate frame MF include components that are common to each other. The rear link unit RL includes a pair of left and right rear main links 61 and a pair of left and right flat link bases 63. One end of the rear main link 61 is provided with a link connection portion 6A for pivotally connecting to the main frame 10 about a horizontal axis. The link connection portion 6A is formed as a sleeve having a horizontal axis. The main frame 10 is provided with a rear connection portion 6B that is pin-connected to the link connection portion 6A. The other end of the rear main link 61 is connected to the intermediate region of the link base 63. Furthermore, a posture maintaining link 62 is installed in the space between the front end region of the rear main link 61 and the front end of the link base 63, spanning between the front end region of the rear main link 61 and the front end of the link base 63. The posture maintaining link 62 is a bent link consisting of two link members that are pivotally connected to each other. The position maintaining link 62 is designed in relation to the structure of the intermediate frame MF so that it does not open beyond a predetermined bending angle (maximum bending angle), and the appropriate position is created at this maximum bending angle. In other words, the limit to which the intermediate frame MF swings downward due to gravity is determined by the position maintaining link 62 (maximum bending angle of the bending link), and the position of the intermediate frame MF at that point is the appropriate position suitable for connection with the blade housing 40. When the intermediate frame MF is lifted, the position maintaining link 62 bends in that direction, allowing the intermediate frame MF to be lifted freely.

[0026] The intermediate frame MF includes a cover plate 70 that functions as a cross member for the link bases 63, a pair of left and right plate-shaped link bases 63, and a crossbar 65 that connects the rear ends of the link bases 63. The cover plate 70 is made up of an arch-shaped arch portion 70a, a left wing portion 70b connected to the left end of the arch portion 70a, and a right wing portion 70c connected to the right end of the arch portion 70a. The left wing portion 70b is connected to the left link base 63, and the right wing portion 70c is connected to the right link base 63. A power connecting unit 25 that connects the input shaft 25b of the mower-side power transmission mechanism 25B and the output shaft 25a of the machine-side power transmission mechanism 25A is fixed to the underside of the arch portion 70a. One guided pin 90, which is a guided member 9A of the intermediate frame MF, is fixed to the left wing portion 70b of the left link base 63 so as to protrude downward, and two guided pins 90 are fixed to the right wing portion 70c so as to protrude downward and spaced apart in the front-to-rear direction. In addition, a guide plate 64 is provided on the outer surface of the rear end region of the link base 63.

[0027] 12, 13, and 14, due to the proper posture of the rear link unit RL maintained by the posture maintaining link 62, the multiple guided pins 90 are positioned to be received in the guide grooves 92 of the guide members 9B of the blade housing 40, and can face the guide grooves 92. This allows the guided pins 90 to smoothly enter the guide grooves 92, with the result that the intermediate frame MF is connected to the blade housing 40. Furthermore, the lower surfaces of the left wing portion 70b and the right wing portion 70c abut against the upper plate 91c of the angled bracket 91, thereby achieving the proper height relationship of the intermediate frame MF with respect to the blade housing 40.

[0028] As shown in Figures 5, 6, and 15 (exploded views of the locking mechanism LM and double locking mechanism DM), the locking mechanism LM is provided in the corner region defined by the link base 63 and crossbar 65 of the intermediate frame MF. Furthermore, a double locking mechanism DM that maintains the locked state of the locking mechanism LM is attached to the locking mechanism LM. In other words, the double locking mechanism DM double-locks the connection between the intermediate frame MF and the blade housing 40 by maintaining the locked state of the locking mechanism LM. The locking mechanism LM is automatically locked by the relative movement between the engaging unit 7A and the engaged unit 7B when the front wheel 2a passes over the blade housing 40 placed on the ground. The locking mechanism LM is also unlocked by operating the swing lever 85 to disengage the locking body 84 from the through-hole 63b and rotate the rotating member 81 and the rotating body 83. At least a portion of this unlocking process can be achieved by the relative movement between the engaging unit 7A and the engaged unit 7B (when the vehicle is traveling). In other words, the double lock mechanism DM automatically maintains the locked state of the lock mechanism LM due to the movement of the lock mechanism LM (displacement for automatic locking) that occurs when the front wheel 2a passes over the blade housing 40, and releases the maintained locked state due to automatic locking displacement in the opposite direction. In other words, the intermediate frame MF and the blade housing 40 are automatically locked when the intermediate frame MF is in a predetermined position relative to the blade housing 40.

[0029] As shown in Figures 16, 17, 18, 19, 20, and 21, the locking mechanism LM includes a rotating member 81 that converts the movement (relative movement) of the intermediate frame MF with respect to the blade housing 40 into rotational movement. The left and right rotating members 81 are provided with a long rod 80 that serves as a common support shaft for the left and right rotating members 81 and serves as a connecting rod that connects the left and right rotating members 81. Here, the rotating member 81 is formed in the shape of a bifurcated swing arm. One end of the rotating member 81 has an engaging portion 81a that engages with a locking rod 97 that functions as an engaged body that constitutes the engaged unit 7B of the blade housing 40 through the rotational movement. Here, the engaging portion 81a is formed in a hook shape. When the engaging portion 81a engages with the locking rod 97, the locking mechanism LM is placed in a locked state.

[0030] The double lock mechanism DM includes a slide pin 82, a rotating body 83 interlocked with the rotating member 81 by the slide pin 82, a swing lever 85 connected to the long rod 80, the rotating body 83 interlocked with the rotating member 81 by the slide pin 82, and a locking body 84 that displaces to a locked position to lock the rotating member 81 and the rotating body 83 as the swing lever 85 swings. The slide pin 82 is a pin bent into a U-shape, with one pin portion referred to as a first pin portion 82a and the other pin portion referred to as a second pin portion 82b. The first pin portion 82a passes through an arc-shaped hole 63a in the link base 63 and is connected to the rotating body 83. The second pin portion 82b passes through a through-hole in the link base 63 and connects the rotating member 81 and the rotating body 83 rotatably but immovably in the axial direction. The swing lever 85 is slidable in the axial direction of the second pin portion 82b and the long rod 80 together with the rotating member 81 and the rotating body 83 via the slide pin 82. A first spring 88a, which is a compression spring, is interposed between the rotating body 83 and the link base 63. This first spring 88a elastically biases the locking body 84 in a direction (a direction in which the locking body 84 presses against the outer surface of the link base 63) to lock (maintain the locked state of the locking mechanism LM, i.e., double lock). The first spring 88a and the second spring 88b are fitted onto the outside of the first pin portion 82a (see FIGS. 17 and 21). Furthermore, the rotating member 81 and the rotating body 83 are connected to a second spring 88b, which is a torsion spring, and the second spring 88b applies a biasing force to the rotating member 81 and the rotating body 83. In other words, the rotating member 81 and the rotating body 83 rotate in conjunction with each other via the second spring 88b. The rotating body 83 rotates about the axis of the second pin portion 82b relative to the rotating member 81, which rotates about the axis of the long rod 80. The swing lever 85 rotates about the axis of the long rod 80, and at that time, the swing lever 85, the rotating member 81, and the rotating body 83 rotate together. A notch is formed in the swing lever 85 to avoid interference with the first pin portion 82a of the slide pin 82. The locking body 84 is fixed to the opposite side of the swing lever 85 from the portion through which the second pin portion 82b passes, i.e., to the upper end region.Displacement of the rocking lever 85, i.e., the locking body 84, in the locking direction is prevented by the locking body 84 coming into contact with the link base 63, but when the rotating body 83, i.e., the rocking lever 85, is rotated to a predetermined rotation angle position, the locking body 84 enters the through-hole 63b provided in the link base 63, and slides to the locking position (a position where the locked state of the locking mechanism LM is maintained, i.e., the double locking position).

[0031] Starting from the state shown in Fig. 16, as the intermediate frame MF moves relative to the blade housing 40, the protrusion of the rotating member 81 comes into contact with the pressing portion 98 fixed to the blade housing 40, as shown in Figs. 18 and 19, and this contact causes the rotating member 81 to rotate. As shown in Figs. 19 and 20, as the movement of the intermediate frame MF relative to the blade housing 40 progresses, the locking body 84 slides and the locking mechanism LM and double locking mechanism DM enter the locked state. At the same time, the swing lever 85, the rotating body 83, the rotating member 81, and the long rod 80 slide and displace, releasing the protrusion of the rotating member 81 from the pressing portion 98. More specifically, as the locking body 84 moves laterally (perpendicular to the travel direction) to the locked position, the protrusion of the rotating member 81 moves away from the pressing portion 98.

[0032] Fig. 17 shows the lock mechanism LM and double lock mechanism DM in a state just before they are locked (a state just before the intermediate frame MF and the blade housing 40 are connected), and Fig. 21 shows the lock mechanism LM in a locked state and the double lock mechanism DM in a locked state. As shown in Figs. 17 and 21, the lock mechanism LM and double lock mechanism DM on the left side described above have different configurations from the lock mechanism LM and double lock mechanism DM on the right side. However, in the mower unit 4 shown in Fig. 4, the lock mechanism LM and double lock mechanism DM on the left side and the lock mechanism LM and double lock mechanism DM on the right side have the same configuration. In an embodiment in which the right and left locking mechanisms LM and double locking mechanisms DM have different configurations, the rotational and sliding displacements of the left locking mechanism LM when it is locked, when the double locking mechanism DM is maintained in a locked state (double lock), and when it is released create rotational and sliding displacements of the rotating member 81 of the right locking mechanism LM via the long rod 80, thereby realizing the locking and releasing of the right locking mechanism LM, and the locking and releasing of the right locking mechanism LM and the locking and double locking mechanisms DM in a locked state. Also, the right double locking mechanism DM may be omitted, and only the locking mechanism LM may be used.

[0033] Next, the connection of the front link unit FL to the machine body connecting unit 5C and the connection of the front link unit FL to the blade housing 40 will be described with reference to Figures 7, 8, 9, 10, and 11. As shown in Figure 7, a mower body connecting unit 5B is provided on the forward-facing side plate 42 of the blade housing 40 in order to connect the front link unit FL to the blade housing 40, and as shown in Figure 8, a machine body connecting unit 5C is provided near the front end of the main frame 10 in order to connect the front link unit FL to the main frame 10.

[0034] The front link unit FL is composed of a link body 50, a mower connector 50B attached to one end of the link body 50, and a machine body connector 50C attached to the other end of the link body 50. The mower connector 50B is connected to the mower-side connecting unit 5B, and the machine body connector 50C is connected to the machine body-side connecting unit 5C. The link body 50 has a left front link 51a made of a round bar or round pipe that is bent in two places, a right front link 51b that has the same shape as the left front link 51a, and a plate-shaped link cross material 51c that connects the left front link 51a and the right front link 51b.

[0035] The process shown in the flow from Figure 8 to Figure 11 shows the connection process for connecting the machine body connecting body 50C of the front link unit FL to the machine body side connecting unit 5C, and the reverse flow from Figure 11 to Figure 8 shows the detachment process for detaching the machine body connecting body 50C from the machine body side connecting unit 5C.

[0036] The mower-side connecting unit 5B has a pair of left and right plate-shaped front stays 54 bolted to the side plates 42 of the blade housing 40. The mower connecting body 50B has a U-shaped support bracket 53a and a cross pin 53b supported at both ends by both leg pieces of the support bracket 53a. An end of the left front link 51a (right front link 51b) is fixed to the outer surface of the bottom piece of the support bracket 53a.

[0037] Upward protrusions are formed on the tips of the left and right front stays 54, and these protrusions are used to form upwardly opening retaining recesses 54a on the upper surfaces of the tip regions. A connecting module 56 is provided to swingably connect the receiving bracket 53a, which is the mower connector 50B, to the front stays 54. The connecting module 56 consists of an arc-shaped stay guide groove 56b provided in the central region of the front stay 54, and a connecting shaft 56a that is detachably inserted into this stay guide groove 56b and holes provided in both leg pieces of the receiving bracket 53a.

[0038] A hole is formed in the tip region of the front stay 54 to insert a roller support shaft 55a, both ends of which are supported by the left and right front stays 54. An anti-scalp roller 55b is provided in the center of the roller support shaft 55a. Each front stay 54 is received in the internal space of each support bracket 53a, with the anti-scalp roller 55b positioned between the left and right support brackets 53a. A notch is machined into the lower part of the leg piece of the support bracket 53a to avoid interference with the roller support shaft 55a.

[0039] The ground angle (vertical displacement angle) of the mower connecting body 50B, i.e., the front link unit FL, is limited by the position of the connecting shaft 56a in the stay guide groove 56b. Furthermore, the shape of the stay guide groove 56b is designed so that the cross pin 53b of the support bracket 53a can be positioned in the retaining recess 54a of the front stay 54. When the cross pin 53b is positioned in the retaining recess 54a of the front stay 54 (proper swing angle), the machine body connecting body 50C of the front link unit FL is positioned in the proper position suitable for connection to the machine body-side connecting unit 5C. Connection between the machine body-side connecting unit 5C and the front link unit FL (machine body connecting body 50C) is achieved through the over-riding movement of the work machine when the front wheels 2a climb over the blade housing 40 placed on the ground. The posture of the machine body connecting body 50C (the posture of the front link unit FL) during this connection process and release process is determined by the position of the connecting shaft 56a in the stay guide groove 56b.

[0040] The vehicle body connecting body 50C, which is the tip of the front link unit FL, is composed of a cross member 52 that connects the tip of the left front link 51a and the right front link 51b. The vehicle body connecting unit 5C is composed of a pair of left and right connecting plates 57 that are bolted to the main frame 10. The connecting plate 57 has a front-rear guide groove 57c formed by cutouts that create an upper edge portion 57a ​​and a lower edge portion 57b. An opening 57d of the front-rear guide groove 57c faces forward, and the front-rear guide groove 57c extends in the fore-and-aft direction of the vehicle body. The lower edge portion 57b has a downward extension piece 57e that extends further from the lower edge portion 57b. The downward extension piece 57e has a triangular shape with an upper surface that is inclined downward, and this upper surface functions as an inclined guide surface 57f that guides the cross member 52 into the opening 57d. The left downward extension piece 57e bends rightward along the connecting line with the lower side 57b, and the right downward extension piece 57e bends leftward along the connecting line with the lower side 57b, so that the distance between the left and right downward extension pieces 57e in the fore-and-aft direction of the vehicle becomes narrower toward the tip. As a result, the front-and-aft guide groove 57c guides the cross member 52 from the opening 57d to the back of the front-and-aft guide groove 57c and restricts it to a predetermined position when the front wheel 2a moves over the blade housing 40 placed on the ground.

[0041] Furthermore, a downward step 57g is formed in the front / rear guide groove 57c so that the groove bottom is lower than the opening 57d. The step 57g passes from the opening 57d of the horizontal member 52 to the groove bottom, thereby creating a proper connection position for the receiving bracket 53a, which is the mower connector 50B, to the front stay 54, which is the mower side connecting unit 5B. The step 57g passes from the groove bottom of the horizontal member 52 to the opening 57d, thereby creating a proper release position for the receiving bracket 53a, which is the mower connector 50B, to the front stay 54, which is the mower side connecting unit 5B.

[0042] As described above, the connection between the machine body side connection unit 5C and the machine body connecting body 50C is achieved by the forward movement of the work machine, and the machine body connecting body 50C is automatically detached from the machine body side connection unit 5C by the backward movement of the work machine (brush cutter).

[0043] During the installation process in which the mower unit 4 is automatically installed in the lower region of the main frame 10 of the work machine, the engaging unit 7A of the intermediate frame MF automatically engages with the engaged unit 7B of the blade housing 40. This automatic engagement movement substantially coincides with the movement of the locking mechanism LM and the double locking mechanism DM.

[0044] 16 to 21, the operation of the locking mechanism LM and the double locking mechanism DM during the process of attaching the intermediate frame MF to the blade housing 40 will be described below.

[0045] (Installation Step #1) Before attaching the mower unit 4 to the underside of the work machine, lower the intermediate frame MF of the mower unit 4 to its lowest position. As shown in Figure 16, set the swing lever 85 to a position where it is almost upright. This positions the protrusion of the rotating member 81 so that it can interfere with the pressing portion 98.

[0046] (Installation Step #2) As shown in Figure 18, when the work machine moves forward and the protrusion of the rotating member 81 comes into contact with the pressing portion 98, the rotating member 81 begins to rotate around the axis of the long rod 80. As the rotating member 81 rotates, the rotating body 83 and slide pin 82 also rotate in conjunction. As the swing lever 85 rotates, the first pin portion 82a of the slide pin 82 clears the alignment step 63c formed in the arc-shaped hole 63a that guides the first pin portion 82a. This alignment step 63c is formed to align the difference between the rotation axis of the rotating member 81 and the rotation axis of the slide pin 82.

[0047] (Installation Step #3) When the first pin portion 82a passes over the alignment step 63c, the rotating body 83 and the slide pin 82 rotate around the axis of the second pin portion 82b of the slide pin 82 by the biasing force of the second spring 88b.

[0048] (Installation Step #4) The hook-shaped engaging portion 81a of the rotating rotating member 81 and the rotating body 83 pinch the lock rod 97, and the lock mechanism LM enters a locked state. At the same time, when the swing lever 85 rotates around the axis of the long rod 80 to a predetermined swing angle, the position of the lock body 84 coincides with the through-hole 63b of the link base 63, and the lock body 84 enters the through-hole 63b due to the biasing force of the first spring 88a, and at the same time, the swing lever 85 slides axially. This locks the swing lever 85, and as a result, the rotation of the long rod 80, the rotating member 81, and the rotating body 83 is locked, and the double lock mechanism DM maintains the locked state of the lock mechanism LM, i.e., the double lock state.

[0049] (Installation Step #5) As the swing lever 85 slides in the axial direction, the rotating member 81 also slides in the axial direction. This sliding displacement of the rotating member 81 causes the engagement portion 81a of the rotating member 81 to disengage from the pressing portion 98, completing the installation process. Simultaneously with this installation process, the aforementioned connecting process is also performed, in which the machine body connecting body 50C of the front link unit FL is connected to the machine body side connecting unit 5C, completing the installation of the mower unit 4 to the machine body.

[0050] Next, the operation of the locking mechanism LM and the double locking mechanism DM in the process of separating the intermediate frame MF from the blade housing 40 will be described.

[0051] (Exit Step #1) First, the swing lever 85 is rotated counterclockwise to create a lateral gap between the engaging portion 81 a of the rotating member 81 and the pressing portion 98 . (Exit step #2) Furthermore, the swing lever 85 is pulled out until the engaging portion 81 a of the rotating member 81 comes to the left side of the pressing portion 98 . (Exit step #3) Rotating the swing lever 85 clockwise releases the engagement between the lock rod 97 of the rotating member 81 and the rotating body 83. This releases the locked state of the double lock mechanism DM and unlocks the lock mechanism LM. Furthermore, the lateral sliding displacement of the long rod 80 accompanying the rotation of the swing lever 85 causes the engagement portion 81a of the rotating member 81 and the pressing portion 98 to become misaligned in the vehicle travel direction, and the engagement portion 81a and the pressing portion 98 no longer interfere with each other in the vehicle travel direction.

[0052] In order to detach the machine body connecting body 50C of the front link unit FL from the machine body side connecting unit 5C, the mower unit 4 is placed on the ground, the double lock mechanism DM is released from its locked state, and the lock mechanism LM is released from its locked state, and the machine is then moved backwards with the connection between the intermediate frame MF and the blade housing 40 released.

[0053] [Another embodiment] (1) In the above-described embodiment, the guide member 9B provided on the blade housing 40 is the guide groove 92, and the guided member 9A provided on the intermediate frame MF is the guided pin 90 guided by the guide groove 92. Alternatively, the guided member 9A may be provided on the blade housing 40, and the guide member 9B may be provided on the intermediate frame MF. Furthermore, the guide member 9B and the guided member 9A may not be formed by the guide groove 92 and the guided pin 90, but may be formed by other interengaging members, such as a mating sleeve, a ball and a conical hole, etc.

[0054] (2) In the above-described embodiment, the position-maintaining link 62 is configured as a bent link, but it may be configured as a link structure or a slide structure other than the bent link structure.

[0055] (3) In the above-described embodiment, the power connecting unit 25 is fixed to the cover plate 70 serving as the cross member of the intermediate frame MF, but the cover plate 70 and the cross member of the intermediate frame MF may be formed as separate members.

[0056] (4) Figure 22 shows another embodiment of the connecting plate 57 shown in Figure 4. In this embodiment, a connecting plate 57h is provided to connect the inner surfaces of the downward extension pieces 57e. This improves the strength of the left and right connecting plates 57. The upper surface of the connecting plate 57h can also be formed as a guide surface for the cross member 52 of the machine body linkage 50C.

[0057] The configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction arises. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0058] The working machine according to the present invention is not limited to engine-driven types, but can also be applied to various other types of working machines. [Explanation of symbols]

[0059] 3: Lifting link mechanism 4:Moore Unit 5B: Mower side connecting unit 5C: Aircraft side connection unit 6A: Link connection part 6B: Rear connection part 7A: Engagement unit 7B: Engaged unit 9A:Guided member 9B: Guide member 10: Mainframe 25: Power coupling unit 25A: Aircraft side power transmission mechanism 25B: Mower side power transmission mechanism 40: Blade housing 50: Link body 50B: Moore connection 50C: Aircraft connection unit 61: Later main link 62: Posture maintenance link 63: Linkbase 63a: arcuate hole 63b: Through hole 63c: Matching step 64: Guide plate 65: Crossbar 70: Cover plate 70a: Arch 70b: Left wing 70c: Right wing 80: Long rod 81: Rotating member 81a: Engagement part 82: Slide pin 82a: First pin 82b: Second pin section 83: Rotating body 84: Locked 85: Oscillating lever 88a: First spring 88b: Second spring 90: Guided pin 91: Angle bracket 91a: Front leg plate 91b: Hind leg plate 91c: Upper board 92: Guide groove 92a: Three-dimensional aperture 92b: Inclined guideway area 92c: Linear guideway area 95: Base bracket 96: Vertical bracket 96a: Anti-roll member 97: Lock Rod 98: Pressing part DM: Double lock mechanism E: Engine FL: Front link unit LM: Locking mechanism MF: Intermediate frame RL: Rear link unit

Claims

1. A work machine in which a mower unit can be attached between the front and rear wheels below the machine body, a lifting link mechanism including a front link unit and a rear link unit arranged at an interval in the longitudinal direction of the machine body; a front connecting portion provided on the airframe and connected to one end of the front link unit; a rear connecting portion provided on the airframe and connected to one end of the rear link unit; a blade housing connected to the other end of the front link unit; an intermediate frame connected to the other end of the rear link unit; a guide member provided on the blade housing; a guided member provided on the intermediate frame; a posture maintaining link connecting the rear link unit and the intermediate frame, The posture maintaining link maintains the intermediate frame in a proper posture that allows the guiding member and the guided member to be aligned with each other.

2. 2. The work machine according to claim 1, wherein the posture maintaining link is a bent link provided between the rear link unit and the intermediate frame, and the bent angle of the posture maintaining link is set so as to create the proper posture.

3. 2. The work machine according to claim 1, wherein the intermediate frame is introduced into a predetermined position relative to the blade housing by alignment caused by relative movement between the guide member and the guided member, and the intermediate frame and the blade housing are automatically locked at the predetermined position.

4. 4. The work machine according to claim 3, wherein the guided member is a guided pin, the guide member has a guide groove formed therein for guiding the guided pin to the predetermined position, and the guide groove comprises an inclined guide surface region whose groove width decreases from the opening toward the terminal end, and a linear guide surface region whose groove width corresponds to the lateral width of the guided pin.

5. 5. The work machine according to claim 3 or 4, further comprising a power coupling unit that couples an input shaft of a mower-side power transmission mechanism that transmits engine power to a blade provided in the blade housing with a machine-side power transmission mechanism that supplies power to the mower-side power transmission mechanism, the power coupling unit being fixed to the underside of a cover plate attached to the intermediate frame as a cross member of the intermediate frame, and the input shaft and the power coupling unit being coupled by the relative movement.

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