Work machine

Abstract

The invention provides a work machine which can properly install a counterweight. This work machine is provided with: a vehicle body; a counterweight disposed at the rear of the vehicle body; a support bracket fixed to the vehicle body; a main arm, the base end of which is rotatably supported by the support bracket and the front end of which is rotatably connected to the counterweight via a connecting member; and a hydraulic cylinder, the base end of which is rotatably supported by the support bracket, the front end of which is rotatably connected to the front end side of the main arm, the main arm being rotated upward by the extension of the hydraulic cylinder to attach the counterweight to the vehicle body, and the main arm being rotated downward by the contraction of the hydraulic cylinder to detach the counterweight from the vehicle body. The support bracket is provided with an auxiliary arm which is driven in conjunction with the upward rotation of the main arm caused by the extension of the hydraulic cylinder, and which pulls the counterweight toward the support bracket side.

Description

Technical Field

[0001] The present invention relates to a working machine equipped with a detachable counterweight. Background Art

[0002] Generally, in a working machine such as a hydraulic excavator, a front working machine is arranged on the front side of the vehicle body, and a counterweight for balancing with the front working machine is arranged on the rear side of the vehicle body. In addition, there is known a working machine equipped with a counterweight loading and unloading device in order to remove the counterweight from the vehicle body during transportation and attach the counterweight to the vehicle body during operation (for example, Patent Document 1).

[0003] The loading and unloading device described in Patent Document 1 rotates the rotating arm by extending a hydraulic cylinder while a counterweight is rotatably mounted on the front end of a rotating arm supported by a back plate, thereby moving the counterweight toward the back plate.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 2922778 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, when the vehicle body is set in an inclined position with a high front and a low rear, if the counterweight is installed using the loading and unloading device of Patent Document 1, the counterweight will tilt around the rotating part of the front end of the rotating arm due to its own weight, and the lower end will be separated from the back plate. Therefore, it is difficult to properly install the counterweight in an inclined position with a high front and a low rear.

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a working machine to which a counterweight can be appropriately mounted.

[0010] Solutions to Solve Problems

[0011] In order to achieve the above-mentioned purpose, the present invention provides a working machine comprising: a vehicle body; a counterweight, which is arranged at the rear of the vehicle body; a support bracket, which is fixed to the vehicle body; a main arm, whose base end is rotatably supported by the support bracket, and whose front end is rotatably connected to the counterweight via a connecting member; and a hydraulic cylinder, whose base end is rotatably supported by the support bracket, and whose front end is rotatably connected to the front end side of the main arm, wherein the main arm is rotated upward by extending the hydraulic cylinder to install the counterweight on the vehicle body, and the main arm is rotated downward by contracting the hydraulic cylinder to remove the counterweight from the vehicle body. The working machine is characterized in that an auxiliary arm is provided on the support bracket, and the auxiliary arm is driven in conjunction with the upward rotation of the main arm caused by the extension of the hydraulic cylinder to pull the counterweight toward the support bracket side.

[0012] Effects of the Invention

[0013] According to the present invention, a working machine to which a counterweight can be appropriately mounted can be obtained. It should be noted that the problems, structures, and effects other than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a side view of a hydraulic excavator.

[0015] Figure 2 It is a rear perspective view of the back plate and the loading and unloading device.

[0016] Figure 3 It is a three-dimensional diagram of the counterweight.

[0017] Figure 4 This is a side view showing a state in which a counterweight placed on an inclined surface with a high front and a low rear is connected to a connecting member.

[0018] Figure 5 It is a side view showing a state before the pin passes through the movement track of the front end portion of the auxiliary arm.

[0019] Figure 6 It is a side view showing a state where the pin is located on the movement trajectory of the front end portion of the auxiliary arm.

[0020] Figure 7 It is a side view showing a state in which the pin has passed the movement trajectory of the front end portion of the auxiliary arm.

[0021] Figure 8 It is a side view showing a state where the mounting of the weight to the back plate has been completed.

[0022] Fig. 9 It is a side view showing a state after the counterweight has been mounted on the back plate and the hydraulic oil has been discharged from the hydraulic cylinder.

[0023] Fig.10 The hydraulic excavator is installed on a sloped land with a low front and a high rear. Figure 8 The corresponding state diagram.

[0024] Fig.11A This is a side view of the auxiliary arm of Modification 1 in a reduced size.

[0025] Fig. 11B This is a perspective view of the auxiliary arm of Modification 1 in a reduced size.

[0026] Fig. 12A This is a side view of the auxiliary arm of Modification 1 in a state where it is extended.

[0027] Fig. 12B This is a perspective view of the auxiliary arm of Modification 1 in a state where it is extended.

[0028] Fig.13A This is a side view of the auxiliary arm of Modification Example 2 in a reduced size.

[0029] Fig. 13B This is a perspective view of the auxiliary arm of Modification Example 2 in a reduced size.

[0030] Fig.14A This is a side view of the auxiliary arm of Modification 2 in a state where it is extended.

[0031] Fig. 14B This is a perspective view of a state in which the auxiliary arm of Modification 2 is extended.

[0032] Fig.15A It is a diagram showing a groove according to Modification 3.

[0033] Fig. 15B It is a diagram showing an auxiliary arm according to Modification 3. DETAILED DESCRIPTION

[0034] The embodiment of the hydraulic excavator 1 (working machine) of the present invention is described using the accompanying drawings. However, the specific example of the working machine is not limited to the hydraulic excavator 1, and any working machine with a counterweight such as a crane truck may be used. In addition, unless otherwise specified, the front, back, left, and right in this specification are based on the perspective of the operator who rides on the hydraulic excavator 1 and operates it.

[0035] Figure 1 is a side view of the hydraulic excavator 1. Figure 1 As shown, the hydraulic excavator 1 includes a lower traveling structure 2 and an upper revolving structure 3 supported by the lower traveling structure 2. The lower traveling structure 2 and the upper revolving structure 3 are examples of a vehicle body.

[0036] The lower traveling body 2 includes a pair of left and right crawler tracks 4 as endless track belts. The pair of left and right crawler tracks 4 rotate independently by driving the traveling motor 5. As a result, the hydraulic excavator 1 travels. However, the lower traveling body 2 may also be wheeled instead of the crawler tracks 4.

[0037] The upper revolving body 3 is supported on the lower traveling body 2 in a manner that allows it to be revolved by the revolving device 6. That is, the upper revolving body 3 rotates relative to the lower traveling body 2 by the rotation of the revolving device 6. The upper revolving body 3 mainly includes: a revolving frame 7 as a base; a cab (driver's seat) 8 arranged on the left side in front of the revolving frame 7; a front working device 9 (working device) installed in the center of the front of the revolving frame 7 in a manner that allows it to rotate in the up-down direction; a back plate 10 (see FIG. 1 ) installed at the rear end of the upper revolving body 3. Figure 2 ); counterweight 20 disposed at the rear of the revolving frame 7; and a loading and unloading device 30 for loading and unloading the counterweight 20 with respect to the back plate 10 (reference Figure 2 ).

[0038] The cab 8 is arranged adjacent to the front working machine 9 in the left-right direction (the width direction of the vehicle body). More specifically, the cab 8 is arranged on the left side (one side in the left-right direction) of the front working machine 9. However, the arrangement of the cab 8 is not limited to the above example, and the cab 8 only needs to be arranged on one side of the front working machine 9 in the left-right direction.

[0039] A space for an operator who operates the hydraulic excavator 1 is formed in the cab 8. A seat for the operator to sit on and an operating device operated by the operator sitting on the seat are arranged inside the cab 8. The operating device receives an operation by the operator for operating the hydraulic excavator 1. When the operator operates the operating device, the lower travel body 2 travels, the upper swing body 3 swings, and the front working device 9 operates. It should be noted that specific examples of the operating device include a lever, a steering wheel, a pedal, a switch, and the like.

[0040] The front working machine 9 includes: a boom 9a supported on the upper rotating body 3 in a manner that allows it to rise and fall; an arm 9b rotatably supported at the front end of the boom 9a; a bucket 9c (ancillary device) rotatably supported at the front end of the arm 9b; a boom cylinder 9d that drives the boom 9a; an arm cylinder 9e that drives the arm 9b; and a bucket cylinder 9f that drives the bucket 9c. It should be noted that the specific example of the ancillary device is not limited to the bucket 9c, and may also be a grab bucket, a cutter, a pulverizer, a crusher, etc.

[0041] Next, refer to Figure 2 and Figure 3 , the structures of the back plate 10, the counterweight 20 and the loading and unloading device 30 are described. Figure 2 It is a rear perspective view of the back plate 10 and the loading and unloading device 30 . Figure 3It is a three-dimensional diagram of the counterweight 20.

[0042] It should be noted that the directions in the following description are defined with reference to the upper rotating body 3. That is, the front side of the operator riding in the cab 8 is set as the "front side of the upper rotating body 3", the opposite side is set as the "rear side of the upper rotating body 3", and the left and right directions when facing the front side are set as the "left and right directions of the upper rotating body 3". However, in the following description, "of the upper rotating body 3" is omitted and only "the front side", "the rear side", and "the left and right directions" are recorded. Similarly, with respect to "the upper side of the upper rotating body 3", "the lower side of the upper rotating body 3", "the front-rear direction of the upper rotating body 3", and "the up-down direction of the upper rotating body 3", "the upper rotating body 3" is also omitted and only "the upper side", "the lower side", "the front-rear direction", and "the up-down direction" are recorded.

[0043] like Figure 2 As shown in FIG. 1 , the back plate 10 is a flat plate-shaped member extending in the vertical direction and the horizontal direction at the rear of the upper rotating body 3 (at the rear end of the upper rotating body 3 in this embodiment) relative to the front working machine 9. Hereinafter, the rearward surface of the back plate 10 (the surface facing the mounted counterweight 20) is referred to as the "back surface 11". The back plate 10 has a pair of first through holes 12L and 12R (at the rear of the upper rotating body 3). Figure 2 12L is omitted in the illustration) and a pair of second through holes 13L and 13R.

[0044] The first through holes 12L, 12R and the second through holes 13L, 13R penetrate the back plate 10 in the thickness direction (front-back direction). The first through holes 12L, 12R are formed at positions separated in the left-right direction across the loading and unloading device 30. The second through holes 13L, 13R are formed at positions separated in the left-right direction across the loading and unloading device 30. The first through holes 12L, 12R and the second through holes 13L, 13R are formed at positions separated in the up-down direction. In more detail, the second through holes 13L, 13R are formed at positions below the first through holes 12L, 12R.

[0045] The counterweight 20 is a heavy object used to achieve a weight balance with the front working machine 9. Hereinafter, the surface of the counterweight 20 facing the front side (the surface facing the back plate 10 when installed) is described as the "belly surface 21". Figure 3 As shown, recesses 22 and 23 are formed on the belly surface 21 of the counterweight 20. The counterweight 20 also includes a pair of first bosses 24L and 24R, a pair of second bosses 25L and 25R, a pair of connecting brackets 26L and 26R, a groove 27 (recess) and a pin 28 (engagement member).

[0046] The recessed portion 22 is a portion that is recessed from the ventral surface 21 toward the rear at the center of the left-right direction and below the recessed portion 23. The recessed portion 23 is a portion that is recessed from the ventral surface 21 toward the rear at the center of the left-right direction and above the recessed portion 22. The width of the recessed portion 23 in the left-right direction is larger than that of the recessed portion 22. In addition, the recessed portions 22 and 23 are connected to each other in the up-down direction. Furthermore, the front surfaces of the recessed portions 22 and 23, the lower surface of the recessed portion 22, and the upper surface of the recessed portion 23 are open.

[0047] The first bosses 24L and 24R are arranged at positions separated in the left-right direction across the recess 22. The second bosses 25L and 25R are arranged at positions separated in the left-right direction across the recess 22. The first bosses 24L and 24R and the second bosses 25L and 25R are arranged at positions separated in the up-down direction. More specifically, the second bosses 25L and 25R are arranged at positions below the first bosses 24L and 24R.

[0048] The first bosses 24L, 24R and the second bosses 25L, 25R protrude forward from the ventral surface 21 of the counterweight 20. In addition, bolt holes are formed on the front surfaces of the first bosses 24L, 24R and the second bosses 25L, 25R. Moreover, when the counterweight 20 is mounted on the back plate 10, the first bosses 24L, 24R and the first through holes 12L, 12R are coaxial in the front-to-back direction, and the second bosses 25L, 25R enter the second through holes 13L, 13R. In this state, the counterweight 20 is fixed to the back plate 10 by screwing bolts from the front surface side of the back plate 10 to the bolt holes of the first bosses 24L, 24R and the second bosses 25L, 25R.

[0049] The connecting brackets 26L and 26R are mounted on the lower surface of the lower end of the defined recessed portion 23 at positions separated in the left-right direction. The connecting brackets 26L and 26R are flat plate-shaped members extending in the front-back direction and the up-down direction. In addition, through holes 29L and 29R that penetrate in the left-right direction are formed in the connecting brackets 26L and 26R. In addition, connecting pins 43L and 43R, which will be described later, of the loading and unloading device 30 are inserted into the through holes 29L and 29R. Thus, the connecting brackets 26L and 26R are connected to the connecting members 36L and 36R, which will be described later, in a rotatable manner.

[0050] The groove 27 is further recessed from the inner wall of the recess 22 toward the rear. In addition, the groove 27 is extended in the vertical direction. More specifically, the groove 27 is defined by the upper wall 27U at the upper end, the side walls 27L and 27R at the left and right ends, and the inner wall 27I (see Figure 5) defines the inner end, and the lower end is determined by the lower wall 27B. In addition, during the process of mounting the counterweight 20 on the back plate 10, the front end of the auxiliary arm 34 of the loading and unloading device 30, which will be described later, enters the groove 27. The groove 27 is an example of a recessed portion that is recessed inward from the ventral surface 21 of the counterweight 20. However, the recessed portion is not limited to a groove shape.

[0051] It should be noted that the pair of side walls 27L and 27R of the present embodiment are parallel. That is, the width of the groove 27 in the left-right direction is the same at all positions. In addition, when the counterweight 20 is installed on the back plate 10, the lower wall 27B of the present embodiment is tilted upward toward the rear (in other words, tilted downward toward the front) to avoid interference with the front end of the auxiliary arm 34.

[0052] The pin 28 has a cylindrical outer shape. The pin 28 is fixed inside the groove 27. That is, the pin 28 is provided on the counterweight 20 at a position lower than the connecting brackets 26L and 26R (the position where the connecting members 36L and 36R are connected). More specifically, both ends of the pin 28 in the axial direction are fixed to a pair of side walls 27L and 27R of the groove 27. Figure 5 As shown, the pin 28 is separated from the upper wall 27U, the inner wall 27I and the lower wall 27B of the recessed groove 27. That is, a space into which the front end of the auxiliary arm 34 can enter is formed between the upper wall 27U, the inner wall 27I and the lower wall 27B of the recessed groove 27 and the pin 28. However, the specific example of the engaging member is not limited to the pin 28.

[0053] The loading and unloading device 30 is a device for loading and unloading the counterweight 20 relative to the back plate 10. Figure 2 As shown, the loading and unloading device 30 is fixed to the back surface 11 of the back plate 10 at the center of the back plate 10 in the left-right direction. The loading and unloading device 30 mainly includes a support bracket 31, a pair of main arms 32L, 32R, a hydraulic cylinder 33, an auxiliary arm 34, a link 35 and a pair of connecting members 36L, 36R.

[0054] The support bracket 31 is arranged at the center of the back plate 10 in the left-right direction (more specifically, between the first through holes 12L, 12R and between the second through holes 13L, 13R). In addition, the support bracket 31 supports the support shafts 37 and 38 extending in the left-right direction. The support shaft 37 (first support shaft) is supported by the support bracket 31 in front of and above the support shaft 38 (second support shaft).

[0055] The main arms 32L and 32R have a long bar-like shape. The main arms 32L and 32R are arranged to be separated in the left-right direction via the hydraulic cylinder 33. The base ends of the main arms 32L and 32R are rotatably supported on the support shaft 37. In addition, the front ends of the main arms 32L and 32R support the support shaft 39 (third support shaft) and the support shaft 40 (fourth support shaft) extending in the left-right direction.

[0056] The hydraulic cylinder 33 includes a cylinder tube 33a and a piston rod 33b, and the cylinder tube 33a has a cylinder bottom chamber and a piston rod chamber inside. The hydraulic cylinder 33 is extended and retracted by supplying and discharging working oil. More specifically, in the hydraulic cylinder 33, the piston rod 33b protrudes (extends) from the cylinder tube 33a by supplying working oil to the cylinder bottom chamber and discharging working oil from the piston rod chamber. On the other hand, in the hydraulic cylinder 33, the piston rod 33b sinks into the cylinder tube 33a (shortens) by discharging working oil from the cylinder bottom chamber and supplying working oil to the piston rod chamber.

[0057] One end of the hydraulic cylinder 33 (the end of the cylinder tube 33a on the cylinder bottom chamber side) is rotatably supported on the support shaft 38. The other end of the hydraulic cylinder 33 (the protruding end of the piston rod 33b) is rotatably supported on the support shaft 39. As a result, the main arms 32L and 32R are extended by the extension of the hydraulic cylinder 33. Figures 4 to 10 On the other hand, the main arms 32L and 32R are rotated in the clockwise direction (upward direction of installing the counterweight 20 on the back plate 10). Figures 4 to 10 The counterclockwise direction (the downward direction to remove the counterweight 20 from the back plate 10) is rotated.

[0058] The auxiliary arm 34 has a long bar-like shape. The base end of the auxiliary arm 34 is rotatably supported on the support shaft 38. Moreover, in the process of installing the counterweight 20 on the back plate 10, the front end of the auxiliary arm 34 enters the groove 27. And, just before the counterweight 20 is installed on the back plate 10, the front end of the auxiliary arm 34 engages with the pin 28 from the rear side, and the pin 28 is pulled in from the rear side to the front side (support bracket 31 side). In more detail, the front end of the auxiliary arm 34 abuts against the pin 28 from the rear side, and the pin 28 is pressed and pulled in from the rear side to the front side. In addition, a locking portion 34a for locking the pin 28 is provided at the front end of the auxiliary arm 34.

[0059] The connecting rod 35 is rotatably connected to the main arm 32R and the auxiliary arm 34 via connecting shafts 41 and 42. More specifically, one end of the connecting rod 35 is rotatably supported by the connecting shaft 41 supported between the base end and the front end of the main arm 32R. In addition, the other end of the connecting rod 35 is rotatably supported by the connecting shaft 42 supported between the base end and the front end of the auxiliary arm 34. The connecting rod 35 rotates (drives) the auxiliary arm 34 in conjunction with the rotation of the main arms 32L and 32R. That is, the auxiliary arm 34 rotates clockwise in conjunction with the clockwise rotation of the main arms 32L and 32R. Figures 4 to 10 In addition, the auxiliary arm 34 rotates in the counterclockwise direction in conjunction with the main arms 32L and 32R. Figures 4 to 10 Rotate counterclockwise.

[0060] The connecting members 36L and 36R are located at positions separated in the left-right direction across the main arms 32L and 32R (at Figure 2 In the example of the support shaft 40, the two ends of the support shaft 40 are supported by the support shaft 40 in a rotatable manner. In addition, the connecting parts 36L and 36R support the connecting pins 43L and 43R in a rotatable manner. And by inserting the connecting pins 43L and 43R into the through holes 29L and 29R of the connecting brackets 26L and 26R, the counterweight 20 is connected to the connecting parts 36L and 36R in a rotatable manner. That is, the counterweight 20 is connected to the front end of the main arm 32L and 32R via the connecting parts 36L and 36R in a rotatable manner.

[0061] Reference Figures 4 to 9 Next, the operation of the loading and unloading device 30 when the counterweight 20 is attached to the back plate 10 in a state where the hydraulic excavator 1 is set on the inclined ground G1 with the front side higher and the rear side lowered will be described. Figure 4 It is a side view showing a state where the counterweight 20 placed on the inclined surface G1 is connected to the connection members 36L and 36R.

[0062] Figure 5 It is a side view showing a state before the pin 28 passes through the movement trajectory T1 of the front end portion of the auxiliary arm 34 .

[0063] Figure 6 It is a side view showing a state in which the pin 28 is located on the movement trajectory T1 of the front end portion of the auxiliary arm 34 .

[0064] Figure 7 It is a side view showing a state where the pin 28 has passed the movement trajectory T1 of the front end portion of the auxiliary arm 34 . Figure 8 1 is a side view showing a state where the mounting of the weight 20 to the back plate 10 has been completed. Fig. 9 It is a side view showing a state after the counterweight 20 has been mounted on the back plate 10 and the hydraulic oil has been discharged from the hydraulic cylinder 33 .

[0065] like Figures 5 to 9 As shown, the front end portion of the auxiliary arm 34 rotates along a moving trajectory T1 in the shape of an arc centered on the support shaft 38. On the other hand, in the process of installing the counterweight 20 on the back plate 10 using the loading and unloading device 30, the pin 28 moves along a moving trajectory T2 that is different from the moving trajectory T1. Moreover, when the hydraulic excavator 1 is viewed from the side, the moving trajectories T1 and T2 intersect at the intersection P (predetermined position). In more detail, in the process of installing the counterweight 20 on the back plate 10, the pin 28 crosses the moving trajectory T1 from the outside (rear side) to the inside (front side) of the arc on the moving trajectory T1. In addition, in the process of installing the counterweight 20 on the back plate 10, after the pin 28 passes through the intersection P, the front end portion of the auxiliary arm 34 passes through the intersection P clockwise.

[0066] First, if Figure 4 As shown in FIG. 1 , a counterweight 20 is placed on the inclined surface G1 at the rear of the hydraulic excavator 1, and the hydraulic cylinder 33 is shortened to connect the connecting members 36L and 36R to the connecting brackets 26L and 26R. Figure 5 As shown in FIG. 1 , the main arms 32L, 32R and the auxiliary arm 34 rotate clockwise in conjunction with each other, and the counterweight 20 connected to the connecting members 36L, 36R moves away from the inclined position G1 with the front being higher and the rear being lower. Figure 6 to Figure 9 As shown, during the process of the counterweight 20 approaching the back plate 10 , the front end portion of the auxiliary arm 34 rotating clockwise enters the groove 27 .

[0067] Here, if Figures 5 to 9 As shown, when the hydraulic excavator 1 is set in the inclined land G1 with the front higher and the rear lower, the back surface 11 of the back plate 10 is inclined in such a way that the upper side is located more rearward and the lower side is located more forward. In other words, the back surface 11 of the back plate 10 is orthogonal to the loading surface of the hydraulic excavator 1. On the other hand, the counterweight 20 is connected to the connecting parts 36L and 36R in a rotatable manner, so the ventral surface 21 is always parallel to the vertical direction due to its own weight. Therefore, the back surface 11 of the back plate 10 and the ventral surface 21 of the counterweight 20 are closer to each other as they are on the upper side, and are separated as they are on the lower side.

[0068] If the hydraulic cylinder 33 is further extended, Figure 6 As shown in FIG. 1 , the pin 28 reaches the moving trajectory T1 (i.e., the intersection P). At this time, the front end of the auxiliary arm 34 is still located below the pin 28 (i.e., upstream of the intersection P in the rotation direction). Figure 6 In the example, the front end of the auxiliary arm 34 is located directly below the pin 28 (in other words, the front end of the auxiliary arm 34 and the pin are located on a straight line extending in the up-down direction), but the specific positional relationship is not limited to this.

[0069] If the hydraulic cylinder 33 is further extended, Figure 7 As shown, after the pin 28 passes through the movement trajectory T1 toward the front side, the front end of the auxiliary arm 34 passes through the intersection point P. In addition, after the front end of the auxiliary arm 34 passes through the intersection point P, the front end of the auxiliary arm 34 contacts the pin 28. More specifically, the auxiliary arm 34 first contacts the rear and lower part of the center of the cylindrical pin 28.

[0070] If the hydraulic cylinder 33 is further extended, Figure 8As shown, the front end of the auxiliary arm 34 rotating clockwise is slidably contacted with the outer peripheral surface of the pin 28 while being wound around (moved) to the rear of the pin 28, pulling the pin 28 to the front side. As a result, the counterweight 20 rotates counterclockwise around the connecting pins 43L and 43R. As a result, the back surface 11 of the back plate 10 is parallel to the ventral surface 21 of the counterweight 20, and the counterweight 20 is attached to the back plate 10 (more specifically, the first protrusions 24L and 24R are coaxial with the first through holes 12L and 12R in the front-back direction, and the second protrusions 25L and 25R enter the second through holes 13L and 13R).

[0071] Then, after the counterweight 20 is fixed to the back plate 10 by bolts, the hydraulic oil is discharged from the cylinder 33a (that is, both the cylinder bottom chamber and the piston rod chamber). Fig. 9 As shown, the main arms 32L, 32R and the auxiliary arm 34 rotate counterclockwise. As a result, the front end of the auxiliary arm 34 leaves the pin 28. On the other hand, the counterweight 20 is fixed to the back plate 10, so the counterweight 20 does not move.

[0072] Fig.10 The hydraulic excavator 1 is installed on the inclined land G2 with the front lower and the rear higher. Figure 8 The corresponding state diagram. Fig.10 As shown in FIG. 1 , when the hydraulic excavator 1 is set at the inclined position G2 with the front lower and the rear higher, the back surface 11 of the back plate 10 is inclined so that the upper side is located more forward and the lower side is located more rearward. On the other hand, the counterweight 20 is connected to the connecting parts 36L and 36R in a rotatable manner, so the ventral surface 21 is always parallel to the vertical direction due to its own weight. Therefore, the back surface 11 of the back plate 10 and the ventral surface 21 of the counterweight 20 are separated more toward the upper side and closer toward the lower side.

[0073] Therefore, if the hydraulic cylinder 33 is extended, after the lower end of the counterweight 20 contacts the back plate 10, the upper end of the counterweight 20 approaches the back plate 10, and the counterweight 20 is attached to the back plate 10. Fig.10 As shown, the front end of the auxiliary arm 34 does not contact the pin 28. Furthermore, if the inclination angle of the front low and rear high inclined land G2 increases, the front end of the auxiliary arm 34 contacts the inner wall 27I of the groove 27 before the lower end of the counterweight 20 contacts the back plate 10.

[0074] According to the above-described embodiment, for example, the following effects are achieved.

[0075] According to the above embodiment, when the hydraulic excavator 1 is installed in the inclined land G1 with a high front and a low rear, the front end of the auxiliary arm 34 pulls the pin 28 forward during the process of attaching the counterweight 20 to the back plate 10. Thus, the counterweight 20 can be properly attached to the back plate 10 even in the inclined land G1 with a high front and a low rear.

[0076] In addition, according to the above embodiment, by providing the locking portion 34a at the front end of the auxiliary arm 34, the pin 28 can be prevented from falling off from the front end of the auxiliary arm 34 due to the weight of the counterweight 20. As a result, when the counterweight 20 is attached to the back plate 10, the pin 28 can be reliably pulled forward.

[0077] According to the above embodiment, the lower wall 27B defining the lower end of the groove 27 is tilted upward toward the rear. Thus, when the counterweight 20 is mounted on the back plate 10, the front end of the auxiliary arm 34 can avoid interference with the lower wall 27B while ensuring the weight of the counterweight 20.

[0078] Furthermore, according to the above embodiment, when the hydraulic excavator 1 is installed in the inclined land G2 with a lower front and a higher rear, the front end of the auxiliary arm 34 abuts against the inner wall 27I of the groove 27 during the process of attaching the counterweight 20 to the back plate 10. This prevents the lower end of the counterweight 20 from colliding with the back plate 10.

[0079] It should be noted that the above-mentioned effect is effective between the inclination angle θ1 of the inclined land G1 with a high front and a low rear and the inclination angle θ2 of the inclined land G2 with a low front and a high rear. In addition, the inclination angles θ1 and θ2 vary according to the fixing position of the pin 28, the length of the auxiliary arm 34, the length of the connecting rod 35, the connection position of the connecting shafts 41 and 42, and the like. For example, the longer the length of the auxiliary arm 34, the larger the inclination angle θ1 at which the above-mentioned effect is effective. On the other hand, the shorter the length of the auxiliary arm 34, the larger the inclination angle θ2 at which the above-mentioned effect is effective. In more detail, the longer the length of the auxiliary arm 34, the more the front end of the auxiliary arm 34 enters the groove 27, so it is necessary to set the end of the lower wall 27B further rearward. When the length of the auxiliary arm 34 becomes above a certain level, the groove 27 passes through the counterweight 20, and the inner wall 27I is no longer provided.

[0080] Modifications 1 and 2

[0081] Reference Figures 11A to 14B The auxiliary arms 50 and 60 of Modifications 1 and 2 are described. It should be noted that detailed description of the common points with the above embodiment is omitted, and the description will focus on the differences. The auxiliary arms 50 and 60 of Modifications 1 and 2 are different from the auxiliary arm 34 of the above embodiment in that they are configured to be retractable.

[0082] Fig.11A This is a side view of the auxiliary arm of Modification 1 in a reduced size. Fig. 11B This is a perspective view of the auxiliary arm of Modification 1 in a reduced size. Fig. 12A This is a side view of the auxiliary arm of Modification 1 in a state where it is extended. Fig. 12B 1 is a perspective view of the auxiliary arm of Modification 1 after being extended. Fig.11A , Fig. 11B , Fig. 12A and Fig. 12B As shown, the auxiliary arm 50 of the modification 1 is composed of a base end member 51 and a front end member 52. The base end member 51 and the front end member 52 are each a long rod-shaped member.

[0083] The base end member 51 is provided with an insertion hole 53 for the support shaft 38, an insertion hole 54 for the connection shaft 42, and three bolt holes 55a, 55b, and 55c. The insertion hole 54 is formed at a position closer to the front end side than the insertion hole 53. The bolt holes 55a, 55b, and 55c are formed separately in the longitudinal direction of the base end member 51 at a position closer to the front end side than the insertion hole 54.

[0084] The front end member 52 is provided with a locking portion 56 and bolt holes 57a, 57b. The locking portion 56 is provided at the front end portion of the front end member 52. The bolt holes 57a, 57b are formed separately in the longitudinal direction of the front end member 52 at a position closer to the base end side than the locking portion 56. In addition, the bolt holes 55a, 55b, 55c and the bolt holes 57a, 57b are formed at the same pitch.

[0085] Then, if Fig.11A and Fig. 11B As shown in FIG. 1 , the auxiliary arm 50 is brought into a contracted state by connecting the two bolt holes 55a and 55b on the base end side to the bolt holes 57a and 57b and screwing the bolts 58a and 58b. Fig. 12A and Fig. 12B As shown, the auxiliary arm 50 is in an extended state by connecting the two bolt holes 55b and 55c on the front end side to the bolt holes 57a and 57b and screwing the bolts 58a and 58b.

[0086] Fig.13A This is a side view of the auxiliary arm of Modification Example 2 in a reduced size. Fig. 13B This is a perspective view of the auxiliary arm of Modification Example 2 in a reduced size. Fig.14A This is a side view of the auxiliary arm of Modification 2 in a state where it is extended. Fig. 14B 2 is a perspective view of the auxiliary arm of Modification Example 2 after being extended. Fig.13A , Fig. 13B , Fig.14A and Fig. 14B As shown, the auxiliary arm 60 of the modification 2 is composed of a base end member 61 and a front end member 62. The base end member 61 and the front end member 62 are respectively long rod-shaped members.

[0087] The base end member 61 is provided with an insertion hole 63 for supporting the shaft 38, an insertion hole 64 for connecting the shaft 42, three bolt holes 65a, 65b, 65c, and a first locking portion 66. The insertion hole 64 is formed at a position closer to the front end side than the insertion hole 63. The bolt holes 65a, 65b, 65c are formed separately in the longitudinal direction of the base end member 61 at a position closer to the front end side than the insertion hole 64. More specifically, the bolt hole 65a is formed at a position closer to the front end side than the bolt hole 65b and closer to the base end side than the bolt hole 65c. The first locking portion 66 is formed at the front end portion of the base end member 61.

[0088] The front end member 62 is provided with a second locking portion 67 and bolt holes 68a, 68b, 68c. The second locking portion 67 is provided at the front end portion of the front end member 62. The bolt holes 68a, 68b, 68c are separately formed in the longitudinal direction of the front end member 62 at a position closer to the base end side than the second locking portion 67. More specifically, the bolt hole 68c is formed at a position closer to the front end side than the bolt hole 68a and closer to the base end side than the bolt hole 68b. In addition, the bolt holes 65a, 65b and the bolt holes 68a, 68b are formed at the same pitch. Furthermore, the bolt holes 65a, 65c and the bolt holes 68a, 68c are formed at the same pitch.

[0089] Then, if Fig.13A and Fig. 13B As shown in FIG. 1 , by connecting the bolt holes 65a and 65b with the bolt holes 68a and 68b and screwing the bolts 69a and 69b, the auxiliary arm 50 is reduced in size. Fig.14A and Fig. 14B As shown, the auxiliary arm 50 is in an extended state by making the bolt holes 65a and 65c communicate with the bolt holes 68a and 68c and screwing the bolts 69a and 69b.

[0090] According to Modifications 1 and 2, the lengths of the auxiliary arms 50 and 60 can be adjusted in accordance with the inclination of the ground on which the hydraulic excavator 1 is installed. Thus, the counterweight 20 can be appropriately attached to the back plate 10 at a wider range of inclination angles θ1 and θ2.

[0091] Modification 3

[0092] Fig.15A It is a diagram showing a groove according to Modification 3. Fig. 15B 2 is a diagram showing an auxiliary arm of Modified Example 3. It should be noted that detailed description of the common points with the above-mentioned embodiment is omitted, and the description will be centered on the differences. In the process of mounting the counterweight 20 on the back plate 10, at least one of the groove 70 and the auxiliary arm 80 of Modified Example 3 has the function of aligning the back plate 10 and the counterweight 20 in the left-right direction, which is different from the groove 27 and the auxiliary arm 34 of the above-mentioned embodiment.

[0093] like Fig.15A More specifically, the pair of side walls 70L and 70R defining the left and right ends of the groove 70 of Modification 3 are spaced wider toward the front and narrower toward the rear.

[0094] like Fig. 15B As shown, the auxiliary arm 80 of the modification 3 has a tapered shape in which the width in the left-right direction narrows toward the front end (towards the rear when entering the groove 70). That is, the auxiliary arm 80 of the modification 3 has a shape that gradually becomes thinner from the base end toward the front end.

[0095] According to the third modification, the opening of the groove 70 is wider and the front end of the auxiliary arm 80 is thinner, so even if the position of the counterweight 20 in the left-right direction is slightly offset, the front end of the auxiliary arm 80 can enter the groove 70. On the other hand, since the inner side of the groove 70 is narrower and the base end of the auxiliary arm 80 is thicker, if the position of the counterweight 20 in the left-right direction is offset, the auxiliary arm 80 contacts the side walls 70L and 70R of the groove 70 during the process of the auxiliary arm 80 entering the inner side of the groove 70, and the counterweight 20 can be corrected to the original position. It should be noted that the shapes of the groove 70 and the auxiliary arm 80 of the third modification can be both or either one.

[0096] The above-mentioned embodiments are merely examples for explaining the present invention, and are not intended to limit the scope of the present invention to these embodiments. A person skilled in the art can implement the present invention in various other forms without departing from the gist of the present invention.

[0097] Explanation of symbols

[0098] 1—hydraulic excavator, 2—lower traveling body (body), 3—upper rotating body (body), 4—crawler, 5—travel motor, 6—rotating device, 7—rotating frame, 8—operating cab, 9—front working machine, 9a—boom, 9b—arm, 9c—bucket, 9d—boom cylinder, 9e—arm cylinder, 9f—bucket cylinder, 10—back plate, 11—back surface, 12L, 12R—first through hole, 13L, 13R—second through hole, 20—counterweight, 21—ventral surface, 22, 23—recess, 24L, 24R—first boss, 25L, 25R—second boss, 26L, 26R—connecting bracket, 27, 70—groove (recess), 27B—lower wall, 27I—inner wall, 27L, 27R , 70L, 70R—side wall, 27U—upper wall, 28—pin (engaging component), 29L, 29R—through hole, 30—loading and unloading device, 31—support bracket, 32L, 32R—main arm, 33—hydraulic cylinder, 33a—cylinder barrel, 33b—piston rod, 34, 50, 60, 80—auxiliary arm, 34a, 56, 66, 67—locking part, 35—connecting rod, 36L, 36R—connecting component, 37, 38, 39, 40—support shaft, 41, 42—connecting shaft, 43L, 43R—connecting pin, 51, 61—base end component, 52, 62—front end component, 53, 54, 63, 64—insertion hole, 55, 57, 65, 68—bolt hole, 58, 69—bolt.

Claims

1. A working machine having: Car body; a counterweight disposed at the rear of the vehicle body; a support bracket fixed to the vehicle body; a main arm, the base end of which is rotatably supported by the support bracket and the front end of which is rotatably connected to the counterweight via a connecting member; as well as A hydraulic cylinder, a base end portion of which is rotatably supported by the support bracket and a front end portion of which is rotatably connected to the front end side of the main arm, The main arm is rotated upward by extending the hydraulic cylinder to install the counterweight on the vehicle body, and the main arm is rotated downward by contracting the hydraulic cylinder to remove the counterweight from the vehicle body. The working machine is characterized in that The supporting bracket is provided with an auxiliary arm, which is driven in conjunction with the upward rotation of the main arm caused by the extension of the hydraulic cylinder to pull the counterweight toward the supporting bracket.

2. The working machine according to claim 1, characterized in that: The auxiliary arm is rotatably connected to the main arm via a link, and a base end portion thereof is rotatably supported by the support bracket.

3. The working machine according to claim 2, characterized in that: The counterweight is provided with a locking component, The auxiliary arm engages with the engaging member at the front end thereof in response to the upward rotation of the main arm caused by the extension of the hydraulic cylinder, thereby pulling the counterweight toward the supporting bracket.

4. The working machine according to claim 3, characterized in that: The engaging member is provided on the counterweight at a position lower than a position at which the connecting member is connected.

5. The working machine according to claim 3, characterized in that: The counterweight is provided with a recessed portion recessed inwardly, The engaging component is disposed in the recess.

6. The working machine according to claim 3, characterized in that: The engaging component is a pin.

7. The working machine according to claim 3, characterized in that: When the main arm is rotated upward by the extension of the hydraulic cylinder, the movement trajectory of the front end of the auxiliary arm intersects the movement trajectory of the engaging member at a predetermined position. When the engaging member is located at the predetermined position, the front end of the auxiliary arm is located below the engaging member. The front end of the auxiliary arm pulls the engaging member from the rear side toward the front side of the engaging member.

8. The working machine according to claim 5, characterized in that: The recessed portion is formed in a groove shape, At least one of the auxiliary arm and the recessed portion is formed in a tapered shape.

9. The working machine according to claim 4, characterized in that: The auxiliary arm is configured to be retractable.

10. The working machine according to claim 4, characterized in that: A locking portion for locking the locking member is provided at the front end portion of the auxiliary arm.

11. The working machine according to claim 5, characterized in that: The recessed portion is formed in a groove shape, The lower wall of the lower end of the recessed portion defining the groove shape is inclined upward toward the rear to avoid interference with the front end of the auxiliary arm during installation of the counterweight.

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