JP2021147783A - Work machine - Google Patents

Abstract

To provide a work machine in which the lateral alignment of the back board and the counterweight can be adjusted.SOLUTION: A work machine comprises: a mounting/dismounting system, which includes a connector which consists of a laterally-extending first support shaft / a laterally-extending second support shaft rotatably connected to a counterweight / a connection member rotatably connected to the first support shaft and the second support shaft, a hydraulic cylinder of which one end is rotatably connected to the first support shaft and the other end is rotatably connected to a bracket at a front side of the first support shaft, and a rotating arm of which one end is rotatably connected to the first support shaft and the other end is rotatably supported with the bracket at the front side of the first support shaft; a counterweight (20) having a guide groove (25a, 25b) of which the lateral width gradually narrows downwards from its top; and a back board having a pin (12a, 12b) which abuts to the guide groove (25a, 25b) to be guided during the process of the counterweight (20) being mounted on the back board.SELECTED DRAWING: Figure 5

Description

The present invention relates to a work machine equipped with a removable counterweight.

Generally, in work machines such as hydraulic excavators and hydraulic cranes, front work machines such as excavators and cranes are provided on the front side of the vehicle body, and counterweights are detachably provided on the rear side of the vehicle body in order to balance with the front work machines. .. Further, a work machine provided with a attachment / detachment device for attaching / detaching a counterweight to / from the back plate of a vehicle body is also known (see, for example, Patent Documents 1, 2 and 3).

The attachment / detachment device is, for example, rotatably connected to a support shaft attached to the upper end of a counterweight and extended in the left-right direction at one end and rotatably connected to a bracket of the vehicle body at the other end. Including the link mechanism.

Japanese Unexamined Patent Publication No. 2016-44512 Japanese Unexamined Patent Publication No. 08-319637 JP-A-2007-162454

In the attachment / detachment device having the above configuration, the back plate and the counterweight are displaced in the left-right direction during the attachment operation due to play of the link mechanism or the like. And since the counterweight is very heavy, it is very difficult to align it in the left-right direction.

The present invention has been made in view of the above-mentioned actual conditions, and an object of the present invention is to position the back plate and the counter weight in the left-right direction in a work machine provided with an attachment / detachment device for attaching / detaching the counter weight to / from the back plate. It will provide a technology that can be easily matched.

In order to achieve the above object, the present invention includes a lower traveling body, an upper rotating body rotatably supported by the lower traveling body, a front working machine supported by the upper rotating body and extending forward, and the like. A work machine including a counterweight that is detachably attached to a back plate provided at the rear of the upper swing body and a detachable device that is supported by the upper swing body and attaches / detaches the counter weight to / from the back plate. The attachment / detachment device includes a bracket attached to the lower part of the back plate, a first support shaft extending in the left-right direction, and a second support shaft extending in the left-right direction and rotatably connected to the counterweight. And a connector having a connecting member rotatably connected to each of the first support shaft and the second support shaft, and one end of the first support shaft in a state where the counterweight is attached to the back plate. A state in which the other end is rotatably connected to the bracket in front of the first support shaft, and the hydraulic cylinder expands and contracts by supplying and discharging hydraulic oil, and the counterweight is attached to the back plate. The counterweight is provided with a rotary arm rotatably connected to the first support shaft at one end and rotatably supported by the bracket in front of the first support shaft at the other end. It has a guide groove whose width in the left-right direction gradually narrows from the upper surface to the lower side, the back plate extends rearward from the back surface facing the counter weight, and the counter weight is attached to the back plate. It is characterized by having a pin that comes into contact with the guide groove and is guided in the process.

According to the present invention, in a work machine provided with an attachment / detachment device for attaching / detaching a counterweight to / from a back plate, the back plate and the counter weight can be easily aligned in the left-right direction. Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a side view of the hydraulic excavator which is a typical example of the work machine which concerns on this invention. It is a rear view of the back plate and the attachment / detachment device. It is a side view of the back plate and the attachment / detachment device. It is a perspective view of a counterweight. It is a figure which shows the positional relationship between a pin and a guide groove, and the positional relationship between a guide hole and a boss in the process of mounting a counterweight on a back plate.

An embodiment of the working machine according to the present invention will be described with reference to the drawings. FIG. 1 is a side view of a hydraulic excavator 1 which is a typical example of a work machine according to the present invention. The specific example of the work machine is not limited to the hydraulic excavator 1, but is a lower traveling body, an upper swivel body, a front work machine, and any machine having a counterweight (for example, a crane, a demolition work machine, an earth drill, etc.). You may. Further, unless otherwise specified, the front, rear, left and right in the present specification are based on the viewpoint of the operator who operates the hydraulic excavator 1.

The hydraulic excavator 1 includes a lower traveling body 2 and an upper rotating body 3 supported by the lower traveling body 2. The lower traveling body 2 includes a pair of left and right crawlers 8. Then, when the rotation of the traveling motor (not shown) is transmitted and the pair of left and right crawlers 8 rotate, the hydraulic excavator 1 travels. However, the lower traveling body 2 may be a wheeled type instead of the crawler 8.

The upper swivel body 3 is supported by the lower traveling body 2 so as to be swivelable. The upper swivel body 3 includes a swivel frame 5 as a base, a front work machine 4 rotatably attached to the center of the front end of the swivel frame 5, and a cab (operation) arranged on the front left side of the swivel frame 5. The seat) 7, the back plate 10 (see FIGS. 2 and 3) arranged at the rear of the swivel frame 5, the counter weight 20 detachably attached to the back plate 10, and the counter weight 20 with respect to the back plate 10. It is mainly provided with a attachment / detachment device 30 (see FIGS. 2 and 3) for attaching / detaching.

The front working machine 4 includes a boom 4a undulatingly supported by the upper swing body 3, an arm 4b swingably supported by the tip of the boom 4a, and a bucket swingably supported by the tip of the arm 4b. The 4c and the hydraulic cylinders 4d, 4e, and 4f for driving the boom 4a, the arm 4b, and the bucket 4c are included.

The cab 7 is formed with an internal space on which an operator who operates the hydraulic excavator 1 is boarded. Inside the cab 7, a seat on which the operator is seated (not shown) and an operating device (steering, pedals, levers, switches, etc.) operated by the operator seated on the seat are arranged. Then, when the operator on the cab 7 operates the operating device, the lower traveling body 2 travels, the upper rotating body 3 turns, and the front working machine 4 operates.

Next, the configurations of the back plate 10, the counterweight 20, and the attachment / detachment device 30 will be described with reference to FIGS. 2 to 4. FIG. 2 is a rear view of the back plate 10 and the attachment / detachment device 30. FIG. 3 is a side view of the back plate 10 and the attachment / detachment device 30. FIG. 4 is a perspective view of the counterweight 20.

As shown in FIGS. 2 and 3, the back plate 10 is a flat plate-shaped member extending in the vertical direction and the horizontal direction at the rear portion of the upper swivel body 3. Hereinafter, among the surfaces of the back plate 10, the surface facing rearward (the surface facing the mounted counterweight 20) will be referred to as “back surface 11”. The back plate 10 has a pair of pins 12a and 12b, a pair of guide holes 13a and 13b, and a pair of bolt holes 14a and 14b. Further, the back plate 10 supports the attachment / detachment device 30 at the central portion of the back surface 11 in the left-right direction.

The pair of pins 12a and 12b, the pair of guide holes 13a and 13b, and the pair of bolt holes 14a and 14b are formed so as to be separated from each other in the left-right direction. In other words, the pair of pins 12a and 12b, the pair of guide holes 13a and 13b, and the pair of bolt holes 14a and 14b are formed on opposite sides of the attachment / detachment device 30.

The pair of pins 12a and 12b have a cylindrical outer shape. The pins 12a and 12b project rearward from the back surface 11 at the upper part of the back plate 10. The pair of guide holes 13a and 13b extend forward from the back surface 11 at the lower part of the back plate 10. The guide holes 13a and 13b do not have to penetrate the back plate 10 as long as they are open to the back surface 11 side of the back plate 10. The pair of bolt holes 14a, 14b penetrate the back plate 10 in the thickness direction between the pins 12a, 12b and the guide holes 13a, 13b in the vertical direction.

The counterweight 20 is a heavy object for balancing the weight with the front working machine 4. Hereinafter, among the surfaces of the counterweight 20, the surface facing upward is referred to as "upper surface 21", and the surface facing forward (the surface facing the back plate 10 when mounted) is referred to as "ventral surface 22". As shown in FIG. 4, the counterweight 20 includes a recess 23, a pair of mounting brackets 24a and 24b, a pair of guide grooves 25a and 25b, a pair of bosses 26a and 26b, and a pair of bolt holes 27a and 27b. Has.

The recess 23 is a recess extending rearward from the ventral surface 22 at the central portion in the left-right direction of the counterweight 20. The recess 23 is a space in which the attachment / detachment device 30 is accommodated when the counterweight 20 is attached to the back plate 10. The pair of guide grooves 25a and 25b, the pair of bosses 26a and 26b, and the pair of bolt holes 27a and 27b are arranged on opposite sides of the recess 23 in the left-right direction.

The pair of mounting brackets 24a and 24b are provided inside the recess 23. The mounting brackets 24a and 24b are formed with through holes 28a and 28b (reference numbers "28a" are not shown) that penetrate in the left-right direction. The counterweight 20 is rotatably connected to the attachment / detachment device 30 via the support shafts 42a and 42b (see FIG. 2) inserted into the through holes 28a and 28b.

The pair of guide grooves 25a and 25b are recessed downward from the upper surface of the counterweight 20 and extend in the front-rear direction. The widths of the guide grooves 25a and 25b in the left-right direction (hereinafter, referred to as "opening width") are gradually narrowed downward. In other words, the distance between the pair of side walls defining the left and right sides of the guide grooves 25a and 25b is gradually narrowed downward.

The opening width of the upper ends of the guide grooves 25a and 25b is larger than the diameter of the pins 12a and 12b. The opening width of the lower ends of the guide grooves 25a and 25b is slightly larger than the diameter of the pins 12a and 12b. Further, the vertical length (groove depth) of the guide grooves 25a and 25b is longer than the diameter of the pins 12a and 12b.

The pair of bosses 26a and 26b project forward from the ventral surface 22 of the counterweight 20. The diameter of the tip of the bosses 26a and 26b is smaller than the diameter of the base end. That is, the bosses 26a and 26b have a tapered shape. The bosses 26a and 26b enter the guide holes 13a and 13b of the back plate 10 in the process of mounting the counterweight 20 on the back plate 10. Further, the bosses 26a and 26b come into contact with the bottom walls of the guide holes 13a and 13b when the counterweight 20 is attached to the back plate 10.

The pair of bolt holes 27a and 27b penetrate the counterweight 20 in the front-rear direction. The bolt holes 27a and 27b are formed at positions that communicate with the bolt holes 14a and 14b of the back plate 10 when the counterweight 20 is attached to the back plate 10. Then, bolts (not shown) for fixing the counterweight 20 to the back plate 10 are screwed into the communicating bolt holes 14a and 27a and the bolt holes 14b and 27b.

The attachment / detachment device 30 is a device for attaching / detaching the counterweight 20 to / from the back plate 10. The attachment / detachment device 30 is fixed to the back surface 11 at the center of the back plate 10 in the left-right direction. As shown in FIGS. 2 and 3, the attachment / detachment device 30 includes a support bracket (bracket) 31, a connector 32, a hydraulic cylinder 33, and rotating arms 34a and 34b (hereinafter, these are collectively referred to as “rotation”. It may be referred to as "moving arm 34").

The support bracket 31 projects rearward from the back surface 11 of the back plate 10. The support bracket 31 is arranged in the central portion of the back plate 10 in the left-right direction (more specifically, between the pair of pins 12a and 12b, the pair of guide holes 13a and 13b, and the pair of bolt holes 14a and 14b). ing. The support bracket 31 supports the hydraulic cylinder 33 and the rotating arm 34.

The support bracket 31 is composed of fixing plates 31a and 31b and support plates 31c, 31d, 31e and 31f. The fixing plates 31a and 31b are fixed to the back surface 11 of the back plate 10 at positions separated in the vertical direction. The support plates 31c, 31d, 31e, and 31f are fixed to the fixing plates 31a and 31b at positions separated in the left-right direction. Further, the support plates 31c, 31d, 31e and 31f project rearward from the fixing plates 31a and 31b and extend in the vertical direction.

The support plates 31c and 31d rotatably support the other end of the hydraulic cylinder 33 via the support shaft 35. The support plates 31c and 31e rotatably support the other end of the rotating arm 34a via the support shaft 36a. The support plates 31d and 31f rotatably support the other end of the rotating arm 34b via the support shaft 36.

The connector 32 connects the counterweight 20, the hydraulic cylinder 33, and the rotating arm 34. More specifically, the connector 32 rotatably connects the counterweight 20 to the hydraulic cylinder 33 and the rotating arm 34 around two orthogonal rotation axes. One of the two orthogonal rotation axes extends in the left-right direction.

The connector 32 includes a support shaft (first support shaft) 41 and support shafts (second support shafts) 42a and 42b (hereinafter, these may be collectively referred to as "support shaft 42"). , 43a, 43b (hereinafter, these may be collectively referred to as "connecting member 43").

The support shaft 41 extends in the left-right direction. Further, one end of the hydraulic cylinder 33 and one ends of the rotating arms 34a and 34b are rotatably connected to the support shaft 41. Further, connecting members 43a and 43b are rotatably connected to the support shaft 41 at both ends outside the rotating arms 34a and 34b.

The support shaft 42 extends in the left-right direction. The support shafts 42a and 42b are inserted into the through holes 28a and 28b of the mounting brackets 24a and 24b. That is, the support shaft 42 is rotatably connected to the counterweight 20 via the mounting brackets 24a and 24b. Further, the connecting members 43a and 43b are rotatably connected to the support shafts 42a and 42b. In other words, the support shaft 42 rotatably connects the connecting member 43 and the counterweight 20.

The connecting member 43 is rotatably connected to each of the support shafts 41 and 42. In other words, the connecting member 43 connects the support shafts 41 and 42. The connecting member 43a includes a first connecting member 44a, a second connecting member 45a, and a support shaft (third support shaft) 46a. The connecting member 43b has the same structure as the connecting member 43a, and includes a first connecting member 44b, a second connecting member 45b, and a support shaft (third support shaft) 46b.

The first connecting member 44a is rotatably connected to the support shaft 41. The second connecting member 45a is rotatably connected to the support shaft 42. The support shaft 46a extends in a direction orthogonal to the support shafts 41 and 42. The extending direction of the support shaft 46a changes depending on the rotation angles of the hydraulic cylinder 33 and the rotation arm 34. The support shaft 46a rotatably connects the first connecting member 44a and the second connecting member 45a.

The hydraulic cylinder 33 is composed of a cylinder tube 33a having a bottom chamber and a rod chamber, and a cylinder rod 33b that appears and disappears from the cylinder tube 33a. The hydraulic cylinder 33 expands and contracts when hydraulic oil is supplied and discharged. More specifically, the hydraulic cylinder 33 is extended by supplying the hydraulic oil to the bottom chamber and discharging the hydraulic oil from the rod chamber. Further, the hydraulic cylinder 33 is reduced by supplying the hydraulic oil to the rod chamber and discharging the hydraulic oil from the bottom chamber.

The cylinder rod 33b (one end of the hydraulic cylinder 33) is rotatably connected to the support shaft 41. The cylinder tube 33a (the other end of the hydraulic cylinder 33) is rotatably connected to the support bracket 31 around the support shaft 35.

The rotating arms 34a and 34b are arranged on opposite sides of the hydraulic cylinder 33 in the left-right direction. One end of the rotating arms 34a and 34b is rotatably connected to the support shaft 41. The other ends of the rotating arms 34a and 34b are rotatably connected to the support bracket 31 around the support shafts 36a and 36b.

Then, with the counterweight 20 attached to the back plate 10, the support shafts 35, 36a, and 36b are located in front of the support shaft 41. Further, the support shafts 36a and 36b are arranged in front of and above the support shaft 35. Further, the support shaft 41 is always located above the virtual line L connecting the centers of the support shafts 35 and 36b regardless of the expansion / contraction state of the hydraulic cylinder 33 (in other words, the position of the counterweight 20).

FIG. 5 is a diagram showing the positional relationship between the pins 12a and 12b and the guide grooves 25a and 25b in the process of mounting the counterweight 20 on the back plate 10, and the positional relationship between the guide holes 13a and 13b and the bosses 26a and 26b. Is.

When the hydraulic cylinder 33 is reduced, the hydraulic cylinder 33 and the rotating arm 34 rotate rearward around the support shafts 35, 36a, 36b, and the counterweight 20 is removed from the back plate 10. Then, when the hydraulic cylinder 33 is reduced to the maximum, the counterweight 20 is placed on the ground behind the hydraulic excavator 1.

On the other hand, when the hydraulic cylinder 33 is extended, the hydraulic cylinder 33 and the rotating arm 34 rotate forward around the support shafts 35, 36a and 36b. At this time, the counterweight 20 advances toward the back plate 10 while rising. Then, when the hydraulic cylinder 33 is extended to the maximum extent, the counterweight 20 comes into contact with the back surface of the back plate 10.

The movement locus when the counterweight 20 is attached to the back plate 10 is an arc shape centered on the support shafts 36a and 36b and having the length of the rotating arm 34 as the radius. The counterweight 20 is located at the bottom when the hydraulic cylinder 33 is maximally contracted, and is located at the top when the hydraulic cylinder 33 is maximally extended.

Here, there is play between the cylinder tube 33a and the support shaft 35, between the cylinder rod 33b and the support shaft 41, and between the rotating arm 34 and the support shafts 36a, 36b, 41. Further, the first connecting members 44a and 44b and the second connecting members 45a and 45b rotate relative to each other around the support shafts 46a and 46b, so that the relative positions of the back plate 10 and the counterweight 20 in the left-right direction change. ..

Therefore, the counterweight 20 may be displaced in the left-right direction from a predetermined position in the process of being attached to the back plate 10. Therefore, as shown in FIG. 5, in the present embodiment, the back plate 10 and the counterweight 20 are aligned in the left-right direction by the pins 12a and 12b and the guide grooves 25a and 25b.

First, when the counterweight 20 advances while rising, the pins 12a and 12b enter the guide grooves 25a and 25b from above. At this time, as shown in FIG. 6A, the positions of the pins 12a and 12b may be deviated from the center of the guide grooves 25a and 25b in the left-right direction. Further, the positions of the bosses 26a and 26b may be deviated from the center of the guide holes 13a and 13b in the left-right direction. Further, the bosses 26a and 26b are located below the guide holes 13a and 13b.

Further, as the counterweight 20 approaches the back plate 10, the pins 12a and 12b move downward in the guide grooves 25a and 25b. At this time, the pins 12a and 12b approach the center of the guide grooves 25a and 25b in the left-right direction while being guided by the side walls of the guide grooves 25a and 25b whose opening width gradually narrows downward. As a result, the guide holes 13a and 13b and the bosses 26a and 26b come close to each other in the vertical and horizontal directions.

When the hydraulic cylinder 33 is extended to the maximum extent, the pins 12a and 12b come into contact with the bottom walls of the guide grooves 25a and 25b, as shown in FIG. 6B. As a result, the back plate 10 and the counterweight 20 are aligned in the left-right direction. Further, the lower ends of the guide holes 13a and 13b and the lower ends of the bosses 26a and 26b have the same height position.

At this time, the back plate 10 and the counterweight 20 are separated from each other by a predetermined distance in the front-rear direction. However, the bolt holes 14a and 27a are aligned and the bolt holes 14b and 27b are aligned in the vertical and horizontal directions. That is, the bolt holes 14a and 27a communicate with each other, and the bolt holes 14b and 27b communicate with each other.

Next, when the bolts are screwed into the communicating bolt holes 14a and 27a and the bolt holes 14b and 27b, the counterweight 20 moves in parallel in the direction approaching the back plate 10. As a result, the bosses 26a and 26b enter the guide holes 13a and 13b. Further, the bosses 26a and 26b abut on the bottom walls of the guide holes 13a and 13b.

Then, the counterweight 20 is attached to the back plate 10 by screwing the bolts until the back plate 10 and the counterweight 20 come into contact with each other. Further, when the bottom chamber and the rod chamber of the hydraulic cylinder 33 are communicated with the hydraulic oil tank, the weight of the counterweight 20 is supported by the bottom walls of the guide holes 13a and 13b.

According to the above embodiment, for example, the following effects are exhibited.

According to the above embodiment, by arranging the other ends of the hydraulic cylinder 33 and the rotating arm 34 (that is, the support shafts 35, 36a, 36b) in front of the support shaft 41, the counterweight 20 is raised while being backed up. Advance toward the plate 10.

Then, in the process of advancing while the counterweight 20 rises, the pins 12a and 12b enter the guide grooves 25a and 25b from above and move downward along the guide grooves 25a and 25b. Here, if the counterweight 20 is displaced in the left-right direction, the pins 12a and 12b move downward while being guided by abutting the side walls of the guide grooves 25a and 25b.

Since the opening widths of the guide grooves 25a and 25b are narrowed downward, the back plate 10 and the counterweight 20 are automatically aligned in the left-right direction in the process of the pins 12a and 12b moving downward. Will be done. Further, when the pins 12a and 12b come into contact with the bottom walls of the guide grooves 25a and 25b, the back plate 10 and the counterweight 20 are automatically aligned in the vertical direction.

Further, according to the above embodiment, the support shaft 41 is always located above the virtual line L. As a result, the attachment / detachment device 30 can remove the counterweight 20 from the back plate 10 only by reducing the hydraulic cylinder 33, and attach the counterweight 20 to the back plate 10 only by extending the hydraulic cylinder 33. In other words, in the process of removing (or mounting) the counterweight 20 from the back plate 10, it is not necessary to combine the expansion and contraction of the hydraulic cylinder 33. As a result, the configuration of the attachment / detachment device 30 can be simplified.

Further, according to the above embodiment, the weight of the counterweight 20 is screwed into the bolt holes 14a, 14b, 27a, 27b by bringing the bosses 26a, 26b into contact with the bottom walls of the guide holes 13a, 13b. It can be supported by bolts and bosses 26a and 26b that are in contact with the bottom walls of the guide holes 13a and 13b. This allows thinner bolts to be used to support the counterweight 20 of the same weight. Further, bolts having the same diameter can support a heavier counterweight 20.

In the above embodiment, an example in which the guide holes 13a and 13b are formed in the back plate 10 and the bosses 26a and 26b are formed in the counterweight 20 has been described, but the arrangement of the guide holes and the bosses is limited to the above example. Not done. That is, one of the boss and the guide hole may be formed on the back surface 11 of the back plate 10, and the other of the boss and the guide hole may be formed on the ventral surface 22 of the counterweight 20.

The above-described embodiments are examples for the purpose of explaining the present invention, and the scope of the present invention is not limited to those embodiments. One of ordinary skill in the art can practice the present invention in various other aspects without departing from the gist of the present invention.

1 Hydraulic excavator 2 Lower traveling body 3 Upper swing body 4 Front work machine 4a Boom 4b Arm 4c Bucket 4d, 4e, 4f, 33 Hydraulic cylinder 5 Swing frame 7 Cab (driver's seat)
8 Crawler 10 Back plate 11 Back surface 12a, 12b Pin 13a, 13b Guide hole 14a, 14b, 27a, 27b Bolt hole 20 Counterweight 21 Top surface 22 Abdominal surface 23 Recession 24a, 24b Mounting bracket 25a, 25b Guide groove 26a, 26b Boss 28a, 28b Through hole 30 Detachable device 31 Support bracket (bracket)
31a, 31b Fixed plate 31c, 31d, 31e, 31f Support plate 32 Connector 34a, 34b Rotating arm 35, 36a, 36b Support shaft 41 Support shaft (first support shaft)
42a, 42b support shaft (second support shaft)
43a, 43b Connecting members 44a, 44b First connecting members 45a, 45b Second connecting members 46a, 46b Support shaft (third support shaft)

Claims (5)

With the lower running body,
An upper swivel body rotatably supported by the lower traveling body and
A front work machine supported by the upper swing body and extending forward,
A counterweight that is detachably attached to the back plate provided at the rear of the upper swing body, and
A work machine provided with an attachment / detachment device that is supported by the upper swing body and attaches / detaches the counterweight to / from the back plate.
The attachment / detachment device is
With the bracket attached to the bottom of the back plate,
A first support shaft extending in the left-right direction, a second support shaft extending in the left-right direction and rotatably connected to the counterweight, and rotatably connected to the first support shaft and the second support shaft, respectively. A connecting tool having a connecting member and a connecting member
With the counterweight attached to the back plate, one end is rotatably connected to the bracket in front of the first support shaft, and the other end is rotatably connected to the bracket in front of the first support shaft. A hydraulic cylinder that expands and contracts depending on supply and discharge,
With the counterweight attached to the back plate, one end was rotatably connected to the first support shaft, and the other end was rotatably supported by the bracket in front of the first support shaft. Equipped with a rotating arm
The counterweight has a guide groove whose width in the left-right direction gradually narrows from the upper surface to the lower side.
The back plate extends rearward from the back surface facing the counter weight, and has a pin that comes into contact with the guide groove and is guided in the process of mounting the counter weight on the back plate. Work machine. In the work machine according to claim 1,
The connecting member
A first connecting member rotatably connected to the first support shaft,
A second connecting member rotatably connected to the second support shaft,
It is characterized by having a third support shaft extending in a direction orthogonal to the first support shaft and the second support shaft and rotatably connected to each of the first connecting member and the second connecting member. Work machine to do. In the work machine according to claim 1,
On the back surface of the back plate, one of a boss and a guide hole into which the boss enters during the process of attaching the counterweight to the back plate is formed.
The other side of the boss and the guide hole is formed on the ventral surface of the counterweight facing the back plate.
A working machine characterized in that the lower end of the boss and the lower end of the guide hole have the same height position when the pin abuts on the bottom wall of the guide groove. In the work machine according to claim 3,
The boss is a work machine characterized by having a tapered shape. In the work machine according to claim 1,
A work machine characterized in that the other end of the rotating arm is rotatably supported by the bracket in front of and above the other end of the hydraulic cylinder.

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