Work vehicles

Abstract

To provide a work vehicle which enables an engagement state between a quick coupler and an attachment to be visually confirmed easily from inside a cab, irrespective of the specifications of the attachment and the specifications of an arm member.SOLUTION: In a wheel loader 1 as an example of a work vehicle according to the present invention, a bucket 23 is mounted via a quick coupler 22. The wheel loader includes: a display device 4 which is provided further on a cab 12 side than a connection body 212 in a lift arm 21, and which displays an engagement state between the quick coupler 22 and the bucket 23; and a cable 5 in which one end part is connected to a coupler cylinder 33 and the other end part is connected to the display device 4 respectively, and which changes the display on the display device 4 in synchronization with a telescopic motion of the coupler cylinder 33. The display device 4 is mounted further on the cab 12 side than the connection body 212 in the lift arm 21.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a work vehicle to which an attachment is attached via a quick coupler. [Background technology]

[0002] In work vehicles such as wheel loaders, a quick coupler is sometimes provided at the tip of an arm member to easily attach an attachment. The quick coupler is provided with a lock pin that engages with the attached attachment to prevent it from coming off.

[0003] For example, the quick coupler disclosed in Patent Document 1 includes a quick coupler body, a lock pin that moves between an engaged position where it engages with an attachment and a disengaged position where it does not engage with the attachment, a cover located on the back surface of the quick coupler body, and a display that moves as the lock pin moves between a first position where it is hidden by the cover and a second position where it is exposed from the cover. When the display is located in the second position, i.e., when the lock pin is in the disengaged position, it is exposed outside the quick coupler body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6212410 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the quick coupler described in Patent Document 1, because the quick coupler itself is equipped with a display that shows the engagement status of the lock pin with the attachment, the display may be hidden by the attachment or the arm member depending on the specifications of the attachment or the arm member. In such cases, the operator in the cab must either leave the cab and go to a location where the display is visible in order to check it, or move the attachment or the arm member to a position where the display is visible, without knowing whether the lock pin is engaged with the attachment.

[0006] Therefore, an object of the present invention is to provide a work vehicle that allows the engagement state between the quick coupler and the attachment to be easily visually confirmed from inside the driver's cab, regardless of the specifications of the attachment or the arm member. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a work vehicle comprising: a vehicle body provided with a driver's cab; an arm member attached to the front of the vehicle body, the arm member having a pair of side plates arranged side by side at a predetermined interval in the vehicle width direction and extending forward of the driver's cab, and a connector connecting the pair of side plates; a quick coupler attached to the tip of the arm member; and an attachment attached to the arm member via the quick coupler, the quick coupler having a pin member inserted into and removed from a pin hole formed in the attachment, and a hydraulic cylinder for driving the pin member, the pin member being inserted into the pin hole when the hydraulic cylinder is extended and being removed from the pin hole when the hydraulic cylinder is contracted, The arm member is attached to the driver's cab side of the connecting body, a display device that displays whether the quick coupler and the attachment are engaged with each other, and a hydraulic cylinder having one end connected to the hydraulic cylinder and the other end connected to the display device. Cable and the display device comprises: The hydraulic cylinder extends and the other end of the cable is pulled toward the one end, thereby switching the display mode of the window from the non-engaged state display unit to the engaged state display unit. It is characterized by: [Effects of the Invention]

[0008] According to the present invention, the engagement state between the quick coupler and the attachment can be easily visually confirmed from inside the cab, regardless of the specifications of the attachment or the arm member. Other problems, configurations, and advantages will become clear from the description of the following embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an external side view showing an example of the configuration of a wheel loader according to an embodiment of the present invention. [Figure 2A] 10 is a diagram illustrating a method for locking the quick coupler and the bucket, showing a state in which the pin member has been removed from the pin hole. FIG. [Figure 2B] 10 is a diagram illustrating a method for locking the quick coupler and the bucket, showing a state in which the pin member is inserted into the pin hole. FIG. [Figure 3] FIG. 2 is a side view illustrating the mounting position of the display device and the routing of cables. [Figure 4] FIG. 10 is a perspective view showing the connection configuration between the cable and the coupler cylinder, showing the state in which the coupler cylinder is contracted. [Figure 5] FIG. 10 is a perspective view showing the connection configuration between the cable and the coupler cylinder, illustrating a state in which the coupler cylinder begins to apply tension to the cable. [Figure 6] 6 is a perspective view showing the connection configuration between the cable and the coupler cylinder, showing a state in which the coupler cylinder is further extended than the state shown in FIG. 5. [Figure 7A] FIG. 10 is a diagram illustrating the state of the cable accompanying the operation of the coupler cylinder, showing the state in which the coupler cylinder is contracted. [Figure 7B] 10A and 10B are diagrams illustrating the state of the cable accompanying the operation of the coupler cylinder, showing the state in which the coupler cylinder is operating in the extension direction. [Figure 8] FIG. 1 is a front view showing an example of the configuration of a display device. [Figure 9] FIG. 2 is a cross-sectional side view showing the internal configuration of the display device, showing a state in which the cables are not pulled. [Figure 10] FIG. 2 is a top view showing the internal configuration of the display device, showing a state in which the cables are not pulled. [Figure 11] FIG. 2 is a cross-sectional side view showing the internal configuration of the display device, showing a state in which a cable is pulled. [Figure 12] FIG. 2 is a top view showing the internal configuration of the display device, showing a state in which a cable is pulled. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, as one aspect of a work vehicle according to an embodiment of the present invention, a wheel loader that performs loading and unloading work by excavating work objects such as earth and sand or minerals and loading them onto a loading destination such as a dump truck will be described.

[0011] <Wheel Loader 1 Configuration> First, the configuration of the wheel loader 1 will be described with reference to FIG.

[0012] FIG. 1 is an external side view showing an example of the configuration of a wheel loader 1 according to an embodiment of the present invention.

[0013] The wheel loader 1 is an articulated work vehicle that is steered by bending the vehicle body near the center. Specifically, a front frame 1A, which forms the front part of the vehicle body, and a rear frame 1B, which forms the rear part of the vehicle body, are connected by a center joint 10 so as to be freely rotatable in the left-right direction, and the front frame 1A bends in the left-right direction relative to the rear frame 1B.

[0014] The vehicle body is provided with four wheels 11, two of which are front wheels 11A and are provided on both the left and right sides of the front frame 1A, and the remaining two are rear wheels 11B and are provided on both the left and right sides of the rear frame 1B. Of the four wheels 11, only the front wheel 11A and rear wheel 11B provided on the left side are shown in FIG. 1. There is no particular restriction on the specific number of wheels 11 provided on the vehicle body.

[0015] A hydraulically driven working device 2 for carrying out loading and unloading work is attached to the front of the front frame 1A. The rear frame 1B is provided with a cab 12 where an operator sits, a machinery room 13 that houses various devices required for driving the wheel loader 1, and a counterweight 14 that maintains balance with the working device 2 to prevent the vehicle body from tilting. On the rear frame 1B, the cab 12 is located at the front, the counterweight 14 at the rear, and the machinery room 13 between the cab 12 and the counterweight 14. Therefore, the working device 2 is located in front of the cab 12.

[0016] The working device 2 has a lift arm 21 as an arm member attached to the front frame 1A so as to be rotatable in the vertical direction, two lift arm cylinders (not shown) as hydraulic cylinders that drive the lift arm 21, a quick coupler 22 attached to the tip of the lift arm 21, a bucket 23 attached to the lift arm 21 via the quick coupler 22, a bucket cylinder 24 as a hydraulic cylinder that drives the bucket 23, and a bell crank 25 rotatably connected to the lift arm 21 and that forms a link mechanism between the bucket 23 and the bucket cylinder 24.

[0017] When hydraulic oil is supplied to the bottom chambers of the two lift arm cylinders and the rods extend, the lift arms 21 rotate upward relative to the front frame 1A. On the other hand, when hydraulic oil is supplied to the rod chambers of the two lift arm cylinders and the rods retract, the lift arms 21 rotate downward relative to the front frame 1A.

[0018] The quick coupler 22 is a connecting device that allows various attachments, including a bucket 23, to be easily attached to and detached from the lift arm 21.

[0019] When hydraulic oil is supplied to the bottom chamber of the bucket cylinder 24 and the rod 240 extends, the bucket 23 rotates upward relative to the lift arm 21 (tilt operation). On the other hand, when hydraulic oil is supplied to the rod chamber of the bucket cylinder 24 and the rod 240 retracts, the bucket 23 rotates downward relative to the lift arm 21 (dump operation). This allows the bucket 23 to scoop up and discharge (discharge) work objects such as soil and minerals.

[0020] In addition to the bucket 23, various attachments include a log attachment as a timber handling device and a plow for removing snow. In this way, the wheel loader 1 can perform various tasks such as gripping and snow removal in addition to cargo handling tasks using the bucket 23.

[0021] (Configuration and operation of quick coupler 22) Next, the configuration and operation of the quick coupler 22 will be described with reference to FIGS. 2A and 2B, and FIG.

[0022] 2A and 2B are diagrams illustrating a method for locking the quick coupler 22 and the bucket 23, with Fig. 2A showing a state in which the pin member 3 has been removed from the pin hole 23A, and Fig. 2B showing a state in which the pin member 3 has been inserted into the pin hole 23A. Fig. 3 is a side view illustrating the mounting position of the display device 4 and the routing of the cable 5.

[0023] The quick coupler 22 has a pin member 3 that is inserted into and removed from a pin hole 23A formed in the rear portion of the bucket 23, and a coupler cylinder 33 that serves as a hydraulic cylinder that drives the pin member 3. In this embodiment, the pin holes 23A are formed so as to penetrate in the left-right direction at both left-right end portions of the bucket 23. Hereinafter, the pin hole 23A formed on the left side (one side) of the rear portion of the bucket 23 will be referred to as the "left pin hole 231," and the pin hole 23A formed on the right side (the other side) of the rear portion of the bucket 23 will be referred to as the "right pin hole 232." Note that, in the left-right direction that is the vehicle width direction of the vehicle body, the left-hand side when the operator in the cab 12 looks forward will be referred to as the left direction, and the right-hand side will be referred to as the right direction.

[0024] The pin member 3 has a left pin portion 31 that is inserted and removed in the left-right direction into the left pin hole 231, and a right pin portion 32 that is inserted and removed in the right-left pin hole 232. The left pin portion 31 is attached to the base end of a cylinder tube 331 of the coupler cylinder 33. On the other hand, the right pin portion 32 is attached to the tip end of a rod 332 of the coupler cylinder 33. In other words, the coupler cylinder 33 is disposed in the center of the back surface of the bucket 23 so that its axial direction is along the left-right direction, and connects the left pin portion 31 and the right pin portion 32 in the left-right direction.

[0025] When hydraulic oil is supplied to the bottom chamber of the coupler cylinder 33, the rod 332 extends, and when hydraulic oil is supplied to the rod chamber, the rod 332 contracts. This extension and contraction of the coupler cylinder 33 causes the pin member 3 to be inserted into and removed from the pin hole 23A.

[0026] 2A, when the rod 332 of the coupler cylinder 33 is contracted, the left pin portion 31 and the right pin portion 32 are positioned closer to the center in the left-right direction, with the left pin portion 31 removed from the left pin hole 231 and the right pin portion 32 removed from the right pin hole 232. Therefore, the quick coupler 22 and the bucket 23 are in a disengaged state, i.e., an unlocked state.

[0027] 2B, the left pin portion 31 moves leftward and is inserted into the left pin hole 231, and the right pin portion 32 moves rightward and is inserted into the right pin hole 232. This causes the quick coupler 22 and the bucket 23 to enter an engaged state, i.e., a locked state.

[0028] More specifically, in the quick coupler 22, the rod 332 extends to the right, and the right pin portion 32 is inserted into the right pin hole 232. A flange portion 32A serving as a stopper is formed between the right pin portion 32 and the tip end of the rod 332, and the flange portion 32A abuts against the outer periphery of the right pin hole 232.

[0029] Meanwhile, a flange portion 31A is also formed between the left pin portion 31 and the base end of the cylinder tube 331. When the cylinder tube 331 moves leftward, the flange portion 31A comes into contact with the outer periphery of the left pin hole 231. This ensures that the left pin portion 31 is securely positioned within the left pin hole 231. The flange portion 32A between the right pin portion 32 and the tip end of the rod 332 has a similar function.

[0030] As shown in Fig. 3, a cable 5 is connected to this coupler cylinder 33. A display device 4 that displays whether or not the quick coupler 22 and the bucket 23 are engaged is connected to the other end of this cable 5. That is, in the wheel loader 1, the engaged state and disengaged state of the quick coupler 22 and the bucket 23 are displayed on the display device 4 via the cable 5.

[0031] Here, the lift arm 21 has a pair of side plates 211 arranged side by side at a predetermined interval in the left-right direction and extending forward of the cab 12, and a connector 212 that connects the pair of side plates 211 in a central region. Note that Fig. 3 shows only the side plate 211 arranged on the left side of the pair of side plates 211, and the connector 212 is shown by a dashed line because it is hidden by the side plate 211 arranged on the left side.

[0032] The display device 4 needs to be placed in a position that is easily visible to the operator inside the cab 12, and in this embodiment, it is provided at the base end of the right side plate 211 of the lift arm 21, which is closer to the cab 12 than the connecting body 212. The specific configuration of the display device 4 will be described later.

[0033] The display device 4 may be provided on either of the pair of side plates 211, and there are no particular restrictions on where it is installed as long as it is on the operator's cab 12 side of the connecting body 212 of the lift arm 21. In Figure 3, the display device 4 is shown by a dashed line because it is hidden by the left side plate 211.

[0034] One end of the cable 5 is connected to the coupler cylinder 33 arranged at the tip end of the pair of side plates 211, and is routed so as to run along the inner surface of the right side plate 211, with the other end connected to the display device 4 arranged at the base end of the right side plate 211. The cable 5 changes the display on the display device 4 in conjunction with the extension and contraction movement of the coupler cylinder 33. Note that the cable 5 is preferably routed, for example, under the connecting body 212 so as not to restrict the field of view of the operator in the cab 12. In FIG. 3, the portion of the cable 5 that is hidden by the left side plate 211 is indicated by a dashed line.

[0035] The cable 5 is one type of connecting member, with one end connected to the coupler cylinder 33 and the other end connected to the display device 4, and changes the display on the display device 4 in conjunction with the extension and contraction movement of the coupler cylinder 33. However, any member other than a cable may be used as the connecting member, as long as it is capable of connecting the coupler cylinder 33 and the display device 4 and changing the display on the display device 4 in conjunction with the extension and contraction movement of the coupler cylinder 33.

[0036] (Connection configuration between cable 5 and coupler cylinder 33) Next, a specific connection configuration between the cable 5 and the coupler cylinder 33 and the movement of the cable 5 accompanying the expansion and contraction movement of the coupler cylinder 33 will be described with reference to FIGS. 4 to 6, 7A and 7B.

[0037] Fig. 4 is a perspective view showing the connection configuration between the cable 5 and the coupler cylinder 33, showing the coupler cylinder 33 in a contracted state. Fig. 5 is a perspective view showing the connection configuration between the cable 5 and the coupler cylinder 33, showing the coupler cylinder 33 starting to apply tension to the cable 5. Fig. 6 is a perspective view showing the connection configuration between the cable 5 and the coupler cylinder 33, showing the coupler cylinder 33 in a state where it is further extended than in the state shown in Fig. 5. Figs. 7A and 7B are diagrams explaining the state of the cable 5 as the coupler cylinder 33 extends and retracts. Fig. 7A shows the coupler cylinder 33 in a contracted state, and Fig. 7B shows the coupler cylinder 33 in an extended state.

[0038] The cylinder tube 331 of the coupler cylinder 33 is provided with an attachment member 34 for attaching one end of the cable 5. The attachment member 34 has a plate 341 provided to protrude from the outer circumferential surface of the cylinder tube 331, a pair of fasteners 342 attached to the outer periphery of the cylinder tube 331, and a pair of bolts 343 that fasten the plate 341 and the pair of fasteners 342 together.

[0039] The plate 341 is formed from a rectangular metal plate having a long side in the axial direction (extension / contraction direction) of the coupler cylinder 33 and a short side in a direction extending beyond the outer circumferential surface of the cylinder tube 331. In this embodiment, the plate 341 is provided at its right end with a protrusion 341A that protrudes upward from the top surface.

[0040] Each of the pair of fasteners 342 is formed by bending a strip-shaped metal plate into a circular shape. One end and the other end of the metal plate are each bent so as to extend radially outward, forming a pair of extending portions 342A. Each of the pair of fasteners 342 is attached to the outer periphery of the cylinder tube 331, and then fixed by fastening the pair of extending portions 342A to both ends of the plate 341 in the long side direction using a pair of bolts 343, with the pair of extending portions 342A in contact with each other.

[0041] The cable 5 includes a cable main body 50 and a bellows-shaped first tube 51 and a second tube 52 attached to both ends of the cable main body 50. The first tube 51 and the second tube 52 each expand and contract in the extension direction of the cable 5. The first tube 51 is provided at one end of the cable 5 that serves as a connection portion with the coupler cylinder 33. The second tube 52 is provided at the other end of the cable 5 that serves as a connection portion with the display device 4 (see FIGS. 9 to 12).

[0042] A relay plate 6 is attached to the tip of the first tube 51 as a relay member that relays the connection with the coupler cylinder 33. The relay plate 6 is a rectangular plate with long sides in the extension direction of the cable 5, and has an upper plate 61 and a lower plate 62 arranged with a predetermined gap in the thickness direction, and a connecting portion 63 that connects the upper plate 61 and the lower plate 62 at their right end portions (the ends on the first tube 51 side).

[0043] The relay plate 6 is attached to the mounting member 34 so that the plate 341 of the mounting member 34 is inserted into the gap between the upper plate 61 and the lower plate 62. That is, the upper plate 61 is disposed on the upper surface side of the plate 341 of the mounting member 34, and the lower plate 62 is disposed on the lower surface side of the plate 341 of the mounting member 34. The relay plate 6 and the plate 341 are not fixed to each other, and the relay plate 6 is slidable relative to the plate 341.

[0044] In this embodiment, the connecting portion 63 of the relay plate 6 is disposed at the right end of the plate 341 of the mounting member 34. Therefore, the cable 5 is attached to the mounting member 34 from the rod 332 side (right side). In other words, the cable 5 extends from the mounting member 34 along the coupler cylinder 33 toward the rod 332 side (right side), and is then routed along the right side plate 211 to extend to the display device 4, as described above.

[0045] A guide groove 61A is formed in the upper plate 61 along the long side direction (i.e., the extension / contraction direction of the coupler cylinder 33) into which a protrusion 341A formed on the plate 341 of the mounting member 34 fits. This allows the plate 341 to move by the length of the guide groove 61A along the extension / contraction direction of the coupler cylinder 33. The length of the guide groove 61A is set according to the extension / contraction length of the rod 332 of the coupler cylinder 33, and in this embodiment, it is shorter than the length when the rod 332 is fully extended.

[0046] A protrusion 341A having a tip formed larger than the width of the guide groove 61A is fitted into the guide groove 61A, thereby preventing the intermediate plate 6 and the plate 341 of the mounting member 34 from separating from each other.

[0047] 4 and 7A, the rod 332 of the coupler cylinder 33 is in a contracted state, and in this state, the protrusion 341A is located at the right end of the guide groove 61A. When hydraulic oil is supplied to the bottom chamber from the state shown in FIGS. 4 and 7A, the rod 332 of the coupler cylinder 33 extends, and the flange portion 32A located on the right side abuts against the outer peripheral surface of the right pin hole 232.

[0048] As shown by the arrow in Fig. 5, the plate 341 of the mounting member 34 attached to the cylinder tube 331 also moves leftward, so the protruding piece 341A moves to the left end of the guide groove 61A. Until the protruding piece 341A reaches the left end, only the plate 341 of the mounting member 34 moves leftward, and the relay plate 6 remains stationary at the position shown in Fig. 4.

[0049] As mentioned above, the guide groove 61A is set to a length shorter than the length of the rod 332 of the coupler cylinder 33 when it is fully extended, so in the state shown in Figure 5, the left pin portion 31 is not fully inserted into the left pin hole 231, and the flange portion 31A does not abut against the outer peripheral surface of the left pin hole 231. Therefore, the rod 332 of the coupler cylinder 33 extends further from the state shown in Figure 5, and the cylinder tube 331 moves further leftward.

[0050] In this case, the protrusion 341A is already positioned at the left end of the guide groove 61A and cannot move further leftward. Therefore, as shown by the arrows in Figures 6 and 7B, the protrusion 341A gets caught on the other end of the guide groove 61A, and the relay plate 6 is pulled leftward. This causes the contracted first tube 51 (see Figures 4, 5, and 7A) to expand, and as shown in Figure 7B, the cable main 50 is pulled toward the first tube 51.

[0051] (Configuration of display device 4) Next, the configuration of the display device 4 will be described with reference to FIGS.

[0052] Fig. 8 is a front view showing an example of the configuration of the display device 4. Fig. 9 is a cross-sectional side view showing the internal configuration of the display device 4, showing a state in which the cable 5 is not pulled. Fig. 10 is a top view showing the internal configuration of the display device 4, showing a state in which the cable 5 is not pulled. Fig. 11 is a cross-sectional side view showing the internal configuration of the display device 4, showing a state in which the cable 5 is pulled. Fig. 12 is a top view showing the internal configuration of the display device 4, showing a state in which the cable 5 is pulled.

[0053] The display device 4 includes a rotating member 41 that rotates about a rotating shaft 410 that extends in the left-right direction (vehicle width direction) of the vehicle body, and a case 42 that houses the rotating member 41. As shown in Figures 9 to 12, the rotating member 41 includes a rotating plate 411 rotatably attached to the rotating shaft 410, an engagement state display unit 412 that displays an engaged state in which the pin member 3 is inserted into the pin hole 23A and the quick coupler 22 and the bucket 23 are engaged, a disengagement state display unit 413 that displays a disengaged state in which the pin member 3 is removed from the pin hole 23A and the quick coupler 22 and the bucket 23 are not engaged, and an attachment portion 414 that is provided on the rotating plate 411 and to which a second tube 52 that is the other end of the cable 5 is attached.

[0054] When the cable main body 50 is pulled toward the first tube 51, the second tube 52 is also pulled toward the first tube 51 (see the arrow in FIG. 11), and tension acts on the attachment portion 414, causing the rotation plate 411 to rotate clockwise in FIGS. 9 and 11. On the other hand, when the tension on the attachment portion 414 weakens, the rotation plate 411 rotates counterclockwise in FIGS. 9 and 11.

[0055] In this embodiment, a spring member 410A having a predetermined biasing force is provided on the rotation shaft 410 of the rotation plate 411. Therefore, the rotation plate 411 will not rotate clockwise in Figures 9 and 11 unless a tension that resists the biasing force of the spring member 410A acts on the attachment portion 414. On the other hand, when the tension acting on the attachment portion 414 is no longer applied or the tension weakens, the rotation plate 411 will return to its original rotation due to the biasing force of the spring member 410A.

[0056] The engaged state display portion 412 and the disengaged state display portion 413 are each formed of a rectangular plate and are provided so as to be perpendicular to the rotating plate 411. The engaged state display portion 412 and the disengaged state display portion 413 are arranged adjacent to each other along the outer edge of the rotating plate 411 on the side opposite the attached portion 414, with the rotating shaft 410 sandwiched between them. As shown in FIGS. 9 and 11 , the angle formed by the engaged state display portion 412 and the disengaged state display portion 413 is set to about 120°, but is not limited to this and can be changed as appropriate depending on the specifications of the display device 4.

[0057] The engaged state display section 412 is shown in blue, for example, because the quick coupler 22 and the bucket 23 are engaged and there is no problem in operating the work implement 2. On the other hand, the disengaged state display section 413 is shown in red, for example, to call attention to the fact that the quick coupler 22 and the bucket 23 are disengaged and there is a risk that the bucket 23 will come off the quick coupler 22 if the work implement 2 is operated. Note that in Figures 8 and 12, the disengaged state display section 413 is shown hatched to easily distinguish between the engaged state display section 412 and the disengaged state display section 413.

[0058] As shown in Fig. 8, the case 42 is configured by forming a U-shaped cross section, and includes a right side wall 421 attached to the right side plate 211, a left side wall 422 disposed opposite the right side wall 421, and a bottom wall 423 connecting the right side wall 421 and the left side wall 422, and has a window portion 43 opening at a position facing the operator's cab 12. Either an engagement state display portion 412 or a disengagement state display portion 413 is disposed in the window portion 43. Fig. 8 shows a state in which the disengagement state display portion 413 is disposed in the window portion 43.

[0059] 9 and 10 , when the cable main body 50 is not pulled toward the first tube 51, the coupler cylinder 33 contracts, the quick coupler 22 and the bucket 23 are disengaged, and a disengagement state display unit 413 is positioned in the window 43. An operator in the cab 12 can confirm that the quick coupler 22 and the bucket 23 are disengaged by visually checking the disengagement state display unit 413 displayed in the window 43. At this time, the engagement state display unit 412 is positioned opposite the bottom wall 423.

[0060] 9 and 10, when the coupler cylinder 33 extends and the cable main body 50 is pulled toward the first tube 51, the second tube 52 is also pulled toward the first tube 51 and contracts, as shown by the arrows in FIGS. 11 and 12. At this time, a tension directed toward the second tube 52 side (in this embodiment, a tension that resists the biasing force of the spring member 410A) acts on the attached portion 414, causing the rotating plate 411 to rotate clockwise in FIGS. 9 and 11, and the display mode of the window 43 switches from the disengagement state display portion 413 to the engagement state display portion 412. As a result, the engagement state display portion 412 is disposed in the window 43, and the operator in the cab 12 can confirm that the quick coupler 22 and the bucket 23 are engaged.

[0061] Furthermore, when the coupler cylinder 33 contracts from the state shown in Figures 11 and 12 to return to the state shown in Figures 9 and 10, the tension acting on the attached portion 414 weakens, and the spring force of the spring member 410A causes it to rotate back counterclockwise in Figures 9 and 11.

[0062] Even if the cable 5 breaks while the coupler cylinder 33 is extending and the cable main body 50 is being pulled toward the first tube 51, the rotating plate 411 will rotate back to the state shown in Figures 9 and 11 due to the biasing force of the spring member 410A, and the disengagement state display section 413 will be displayed in the window 43. Therefore, the display device 4 will not display the engagement state display section 412 in the window 43 even if there is a possibility that the quick coupler 22 and the bucket 23 are not engaged.

[0063] In this way, the display device 4, which indicates whether the quick coupler 22 and bucket 23 are engaged or not, is provided on the side of the cab 12 rather than the connecting body 212 of the lift arm 21, and the engagement status display section 412 and the non-engagement status display section 413 are displayed in the window section 43 formed facing the cab 12. Therefore, regardless of the specifications of the bucket 23 or the lift arm 21, the engagement status of the quick coupler 22 and bucket 23 can be easily visually confirmed from inside the cab 12.

[0064] In addition, in this embodiment, the coupler cylinder 33 and one end of the cable 5 are connected via an intermediate plate 6 in which a guide groove 61A is formed, so that it is possible to prevent the cable 5 from being pulled with excessive force when the stroke amount of the coupler cylinder 33 (the amount of extension and contraction of the rod 332) is large.

[0065] The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of the above-described embodiments with configurations of other embodiments, and it is also possible to add configurations of other embodiments to the configuration of the above-described embodiments. Furthermore, it is also possible to add, delete, or replace part of the configuration of the above-described embodiments with other configurations.

[0066] For example, in the above embodiment, a wheel loader 1 was used as an example of a work vehicle, but the present invention is not limited to this, and there are no particular restrictions on the work vehicle as long as an attachment can be attached via a quick coupler 22.

[0067] Furthermore, in the above embodiment, the display device 4 has a display form in which the window portion 43 is switched between the engagement state display portion 412 and the non-engagement state display portion 413 when the tension of the cable 5 acts to rotate the rotating plate 411, but this is not limited to this, and there are no particular restrictions on the display form as long as the display form is one in which the engagement state display portion 412 and the non-engagement state display portion 413 can be switched.

[0068] Furthermore, in the above embodiment, the plate 341 of the mounting member 34 attached to the coupler cylinder 33 is provided with a protrusion 341A, and the relay plate 6 is provided on the cable 5 side, but this is not limited to this, and for example, the protrusion 341A may be provided on the cable 5 side, and the relay plate 6 may be provided on the coupler cylinder 33 side.

[0069] Furthermore, the mounting position and mounting direction between the coupler cylinder 33, the cable 5, and the display device 4 are not limited to the configuration described in the above embodiment, as long as the relationship between the extension and contraction direction of the coupler cylinder 33 and the display method on the display device 4 is correct. [Explanation of symbols]

[0070] 1: Wheel loader (work vehicle) 3: Pin material 4:Display device 5: Cable (connecting part) 6: Relay plate (relay component) 12: Driver's cab 21: Lift arm (arm component) 22: Quick Coupler 23: Bucket (attachment) 23A: Pin hole 33: Coupler cylinder (hydraulic cylinder) 41: Rotating member 43: Window 61A: Guide groove 211: Side panel 212: Connector 341A: Projection piece 412: Engagement status display unit 413: Non-engagement state display unit 414: Mounting part

Claims

1. A vehicle body provided with a driver's cab; an arm member attached to a front portion of the vehicle body, the arm member having a pair of side plates arranged side by side at a predetermined interval in the vehicle width direction and extending forward of the driver's cab, and a connector connecting the pair of side plates; a quick coupler attached to a tip end of the arm member; an attachment attached to the arm member via the quick coupler, The quick coupler is a pin member inserted into a pin hole formed in the attachment; a hydraulic cylinder that drives the pin member, The pin member is The hydraulic cylinder is inserted into the pin hole by extending, and is removed from the pin hole by contracting. In work vehicles, a display device attached to the arm member closer to the cab than the connecting body, the display device indicating whether the quick coupler and the attachment are engaged with each other; a cable having one end connected to the hydraulic cylinder and the other end connected to the display device, The display device includes: an engagement state indicator that indicates an engagement state in which the pin member is inserted into the pin hole and the quick coupler and the attachment are engaged; a disengagement state display unit that displays a disengagement state in which the pin member is removed from the pin hole and the quick coupler and the attachment are not engaged with each other; a window portion that is opened at a position facing the driver's cab and in which either the engagement state display portion or the disengagement state display portion is disposed; and The cable When the hydraulic cylinder is extended and the other end is pulled toward the one end, the display mode in the window is switched from the non-engaged state display portion to the engaged state display portion. A work vehicle characterized by:

2. The work vehicle according to claim 1, The display device includes: the engagement state indicator and the disengagement state indicator are provided, and the vehicle further includes a rotation member that rotates around a rotation axis extending in the vehicle width direction, The cable The hydraulic cylinder extends and pulls the other end toward the one end, thereby rotating the rotary member and switching the display mode in the window from the non-engaged state display section to the engaged state display section. A work vehicle characterized by:

3. The work vehicle according to claim 2, The rotating member is A spring member provided on the rotating shaft and having a predetermined biasing force is provided. A work vehicle characterized by:

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