Work Machine

Abstract

To provide a work machine that can appropriately protect a side surface of an attachment cylinder.SOLUTION: A work machine comprises a side guard (21) having plates (23 to 30) which are arranged to face an attachment cylinder (18) in a width direction of a front work machine and mutually connected in a state of being rotatable relatively to each other around a rotation center of a second link rod (19b) such that the amount of overlap therebetween increases or decreases according to the rotation of the second link rod. Among the mutually connected plates (23 to 30), the plate (23) at one end in the rotation direction rotates integrally with the second link rod (19b), and the plate (30) at the other end in the rotation direction is fixed to an arm (13).SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a work machine equipped with an attachment cylinder. [Background technology]

[0002] A work machine used for demolition work at high altitudes, for example, comprises a boom supported on an upper rotating body so that it can be raised and lowered, an arm supported rotatably at the end of the boom, an attachment supported rotatably at the end of the arm, an attachment cylinder that expands and contracts by supplying and discharging hydraulic oil, and a link mechanism that dumps the attachment when the attachment cylinder extends and crowds the attachment when the attachment cylinder retracts.

[0003] Furthermore, in order to protect the attachment cylinder, a cylinder protection cover may be attached to such a work machine (see, for example, Patent Document 1). The cylinder protection cover described in Patent Document 1 protects the attachment cylinder by covering the cylinder rod with a bellows-shaped flexible sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-163958 A Summary of the Invention [Problem to be solved by the invention]

[0005] When demolition work is performed in a narrow space surrounded by obstacles, there is a possibility that the side of the attachment cylinder may come into contact with the obstacles when the upper rotating body rotates. However, the cylinder protective cover described in Patent Document 1 can only protect the attachment cylinder from dust, and cannot protect the attachment cylinder from obstacles such as rebar and concrete.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a work machine that can adequately protect the side surface of an attachment cylinder. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a working machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a front working machine supported and operated by the upper rotating body, the front working machine having a boom supported on the upper rotating body so as to be able to be raised and lowered, an arm rotatably supported on the tip of the boom, an attachment rotatably supported on the tip of the arm, an attachment cylinder which expands and contracts by supplying and discharging hydraulic oil, and a link mechanism which dumps the attachment when the attachment cylinder is extended and crowds the attachment when the attachment cylinder is contracted, the arm having a pair of side surfaces which face each other in a width direction of the front working machine, a ventral surface which is connected to each other at ends of the pair of side surfaces and faces the boom when the arm is folded towards the boom, and a back surface which is connected to each other at ends of the pair of side surfaces and faces the ventral surface in a direction perpendicular to the width direction of the front working machine, the attachment cylinder is disposed on the ventral side of the arm, and the link mechanism comprises, on the rear side of the arm, a first link rod having one end rotatably connected to the attachment, and a second link rod that is rotatably supported on the side of the arm, one end protruding to the rear side of the arm and rotatably connected to the other end of the first link rod, and the other end protruding to the ventral side of the arm and rotatably connected to the attachment cylinder, and a side guard having a plurality of plates connected to each other in a state that they can rotate relatively around a rotation center of the second link rod so that an amount of overlap between them increases and decreases in response to rotation of the second link rod, the side guard being disposed opposite the attachment cylinder in the width direction of the front working machine and Effect of the Invention

[0008] According to the present invention, the side surface of the attachment cylinder can be appropriately protected. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is a side view of a working machine according to the present invention. [Diagram 2] FIG. 13 is a diagram showing the attitude of the cutter when the hydraulic cylinder is contracted. [Diagram 3] FIG. 13 is a diagram showing the attitude of the cutter when the hydraulic cylinder is extended. [Figure 4] FIG. [Diagram 5] FIG. 4 is a perspective view of the periphery of a plate at one end in the rotation direction. [Figure 6] FIG. 13 is an exploded perspective view of adjacent plates. [Figure 7] FIG. 11 is a perspective view of the periphery of the plate at the other end in the rotation direction. [Figure 8] FIG. 13 is a view showing the side guard when the hydraulic cylinder is retracted. [Figure 9] FIG. 13 is a view showing the side guard when the hydraulic cylinder is extended. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of a work machine according to the present invention will be described with reference to the drawings. Fig. 1 is a side view of a work machine 1 according to the present invention. In this specification, front, rear, left and right are based on the viewpoint of an operator who is on board and operates the work machine 1, unless otherwise specified.

[0011] The work machine 1 comprises a lower traveling body 2 and an upper rotating body 3 supported by the lower traveling body 2. The lower traveling body 2 is provided with a pair of left and right crawlers 8. When the rotation of a traveling motor (not shown) is transmitted to rotate the pair of left and right crawlers 8, the work machine 1 travels. However, the lower traveling body 2 may be of a wheel type instead of the crawlers 8.

[0012] The upper rotating body 3 is rotatably supported by the lower traveling body 2. The upper rotating body 3 mainly comprises a rotating frame 5 serving as a base, a cab (driver's seat) 7 arranged on the front left side of the rotating frame 5, a front working implement 10 attached to the center of the front end of the rotating frame 5 so as to be rotatable in the vertical direction, and a counterweight 6 arranged at the rear of the rotating frame 5 to balance the weight of the front working implement 10.

[0013] The cab 7 defines an internal space in which an operator who operates the work machine 1 sits. Inside the cab 7, there are arranged a seat (not shown) on which the operator sits, and operation devices (steering wheel, pedals, levers, switches, etc.) operated by the operator seated in the seat. When the operator in the cab 7 operates the operation devices, the lower traveling body 2 travels, the upper rotating body 3 rotates, and the front work implement 10 operates.

[0014] The front working machine 10 operates while being supported by the upper rotating body 3. As shown in Fig. 1, the front working machine 10 mainly comprises a boom 11, a first arm 12, a second arm 13, a cutter (attachment) 14, a boom cylinder 15, a first arm cylinder 16, a second arm cylinder 17, an attachment cylinder 18, a link mechanism 19, and a cylinder guard 20. Note that the front working machine 10 is not limited to a multi-arm type having the first arm 12 and the second arm 13, and may be a single-arm type having only one of the first arm 12 and the second arm 13.

[0015] The boom 11 is supported by the upper rotating body 3 so that it can be raised and lowered. The boom 11 is raised and lowered relative to the upper rotating body 3 by the extension and contraction of a boom cylinder 15. The first arm 12 is rotatably attached to the tip of the boom 11. The first arm 12 is rotated relative to the boom 11 by the extension and contraction of a first arm cylinder 16. The second arm 13 is rotatably attached to the tip of the first arm 12. The second arm 13 is rotated relative to the first arm 12 by the extension and contraction of a second arm cylinder 17.

[0016] The second arm 13 has an abdominal surface 13a, a back surface 13b, a left side surface (side surface) 13c, and a right side surface (not shown). The left side surface 13c and the right side surface (a pair of side surfaces) are surfaces that face each other in the left-right direction (width direction of the front working machine 10). The abdominal surface 13a and the back surface 13b are surfaces that face each other in a direction perpendicular to the left-right direction. Furthermore, the abdominal surface 13a is a surface that faces the boom 11 when the second arm cylinder 17 contracts and the second arm 13 is folded toward the boom 11. Furthermore, the abdominal surface 13a and the back surface 13b are connected to the ends of the left side surface 13c and the right side surface, respectively.

[0017] Fig. 2 is a diagram showing the posture of the cutter 14 when the attachment cylinder 18 is contracted. Fig. 3 is a diagram showing the posture of the cutter 14 when the attachment cylinder 18 is extended. Note that the cylinder guard 20 is omitted from Figs. 2 and 3.

[0018] The cutter 14 is an example of an attachment for grasping and demolishing an object (such as a building). As shown in Fig. 2 and Fig. 3, the cutter 14 mainly includes a mounting bracket 14a, a rotating motor 14b, a pair of blades 14c and 14d, and a pair of hydraulic cylinders 14e and 14f. Note that the attachment is not limited to the cutter 14, and may be a bucket, a hook, a lifting magnet, a breaker, a fork, or the like.

[0019] The mounting bracket 14a is rotatably supported at the tip of the second arm 13 by a pin 14g extending in the left-right direction (the width direction of the front working machine 10). The mounting bracket 14a is also rotatably connected to one end of a first link rod 19a (described later) by a pin 14h extending in the left-right direction. The pin 14h is located closer to the back surface 13b of the second arm 13 than the pin 14g.

[0020] The swing motor 14b rotates the components 14c to 14f relative to the mounting bracket 14a by supplying and discharging hydraulic oil. The swing motor 14b rotates the components 14c to 14f about a rotation axis extending in a direction perpendicular to the pins 14g and 14h. The hydraulic oil is supplied to the swing motor 14b from a hydraulic pump (not shown) mounted on the upper swing body 3, and flows back from the swing motor 14b to a hydraulic oil tank (not shown) mounted on the upper swing body 3.

[0021] The pair of blades 14c, 14d are opened and closed by supplying and discharging hydraulic oil to the pair of hydraulic cylinders 14e, 14f. More specifically, the pair of blades 14c, 14d are closed by supplying hydraulic oil to the bottom chambers of the hydraulic cylinders 14e, 14f and discharging hydraulic oil from the rod chambers. On the other hand, the pair of blades 14c, 14d are opened by supplying hydraulic oil to the rod chambers of the hydraulic cylinders 14e, 14f and discharging hydraulic oil from the bottom chambers.

[0022] The attachment cylinder 18 expands and contracts by supplying and discharging hydraulic oil. The attachment cylinder 18 has a cylinder tube 18a, a piston (not shown), a cylinder rod 18b, and a cap 18c. The attachment cylinder 18 is disposed on the abdominal surface 13a side of the second arm 13. More specifically, the attachment cylinder 18 extends in the longitudinal direction of the second arm 13 along the abdominal surface 13a of the second arm 13. In addition, the base end of the cylinder tube 18a of the attachment cylinder 18 is rotatably supported on the base end side of the second arm 13, and the tip end of the cylinder rod 18b is rotatably connected to the other end of a second link rod 19b described later.

[0023] The cylinder tube 18a is a cylindrical member capable of supplying and discharging hydraulic oil. The base end side of the cylinder tube 18a is closed and the tip end side is open. The piston reciprocates within the cylinder tube 18a. The piston also divides the internal space of the cylinder tube 18a into a bottom chamber on the base end side and a rod chamber on the cap 18c side.

[0024] One end of the cylinder rod 18b is connected to the piston, and the other end protrudes to the outside of the cylinder tube 18a through a cap 18c. The cap 18c is attached to the tip of the cylinder tube 18a with a bolt (not shown) or the like. A through hole is formed in the cap 18c to allow the cylinder rod 18b to protrude and to prevent the piston from protruding.

[0025] When hydraulic oil is supplied from the hydraulic pump to the bottom chamber and flows back from the rod chamber to the hydraulic oil tank, the piston moves in a direction that causes the cylinder rod 18b to protrude from the cylinder tube 18a (hereinafter, this action is referred to as "extension of the attachment cylinder 18"). On the other hand, when hydraulic oil is supplied from the hydraulic pump to the rod chamber and flows back from the bottom chamber to the hydraulic oil tank, the piston moves in a direction that causes the cylinder rod 18b to retract into the cylinder tube 18a (hereinafter, this action is referred to as "contraction of the attachment cylinder 18").

[0026] The link mechanism 19 is connected to the cutter 14 and the attachment cylinder 18. The link mechanism 19 rotates the cutter 14 relative to the second arm 13 by extension and contraction of the attachment cylinder 18. As shown in Figures 2 and 3, the link mechanism 19 has a long rod-shaped first link rod 19a, a pair of long rod-shaped second link rods 19b, and pins 19c, 19d, and 19e extending in the left-right direction.

[0027] The first link rod 19a is disposed on the rear surface 13b side of the second arm 13. The first link rod 19a extends along the rear surface 13b of the second arm 13. However, the first link rod 19a does not need to be parallel to the rear surface 13b. One end of the first link rod 19a is rotatably connected to the mounting bracket 14a by a pin 14h. The other end of the first link rod 19a is rotatably connected to one end of a pair of second link rods 19b by a pin 19d.

[0028] The pair of second link rods 19b are rotatably supported by pins 19c on the left side surface 13c and the right side surface of the second arm 13. One end of each of the pair of second link rods 19b protrudes toward the back surface 13b of the second arm 13, and the other end protrudes toward the abdominal surface 13a of the second arm 13. One end of each of the pair of second link rods 19b (the end on the back surface 13b side) is rotatably connected to the other end of the first link rod 19a by a pin 19d. The other end of each of the pair of second link rods 19b (the end on the abdominal surface 13a side) is rotatably connected to the tip of the cylinder rod 18b by a pin 19e.

[0029] As shown in Fig. 2, when the attachment cylinder 18 is contracted, the second link rod 19b rotates about the pin 19c in the counterclockwise direction in Fig. 2. In other words, the second link rod 19b rotates about the pin 19c such that the end on the back surface 13b side moves to the tip side of the second arm 13 and the end on the abdominal surface 13a side moves to the base end side of the second arm 13.

[0030] As a result, the first link rod 19a moves at the position of the pin 14h in a direction pushing the cutter 14. As a result, the cutter 14 rotates in the direction shown by the arrow in Fig. 2 (i.e., a crowding motion). Note that the "crowding motion" is a motion that rotates the cutter 14 toward the abdominal surface 13a of the second arm 13.

[0031] On the other hand, as shown in Fig. 3, when the attachment cylinder 18 is extended, the second link rod 19b rotates about the pin 19c in the clockwise direction in Fig. 3. In other words, the second link rod 19b rotates about the pin 19c such that the end on the back surface 13b side moves toward the base end side of the second arm 13 and the end on the abdominal surface 13a side moves toward the tip side of the second arm 13.

[0032] As a result, the first link rod 19a moves at the position of the pin 14h in a direction to pull the cutter 14. As a result, the cutter 14 rotates in the direction shown by the arrow in Fig. 3 (i.e., performs a dumping operation). Note that the "dumping operation" refers to an operation of rotating the cutter 14 toward the back surface 13b of the second arm 13.

[0033] Fig. 4 is a perspective view of the front guard 21. Fig. 5 is a perspective view of the periphery of the plate 23 at one end in the rotation direction. Fig. 6 is an exploded perspective view of the adjacent plates 23, 24, and 25. Fig. 7 is a perspective view of the periphery of the plate 30 at the other end in the rotation direction. Fig. 8 is a view showing the side guard 22 when the attachment cylinder 18 is contracted. Fig. 9 is a view showing the side guard 22 when the attachment cylinder 18 is extended.

[0034] The cylinder guard 20 serves to protect the attachment cylinder 18 from objects to be dismantled by the work machine 1 and from obstacles present around the objects to be dismantled. When the work machine 1 is used at a demolition site, "obstacles" include, for example, concrete ceilings, walls, and floors, as well as rebar exposed therefrom. As shown in Figs. 4 to 8, the cylinder guard 20 includes a front guard 21 and a pair of side guards 22.

[0035] The front guard 21 is fixed to the other end of the second link rod 19b on the side of the abdominal surface 13a of the second arm 13 (i.e., the side of the pin 19e) that is closer to the pin 19c. The front guard 21 also protrudes from the second link rod 19b on the side opposite the pin 19c. Furthermore, the front guard 21 rotates together with the second link rod 19b as the attachment cylinder 18 expands and contracts. The rotating tip of the front guard 21 is a free end.

[0036] More specifically, the front guard 21 rotates in a direction approaching the attachment cylinder 18 as the attachment cylinder 18 contracts. Meanwhile, as shown in Fig. 9, the front guard 21 rotates in a direction away from the attachment cylinder 18 as the attachment cylinder 18 extends. Furthermore, as shown in Figs. 8 and 9, the front guard 21 is interposed between the cutter 14 and the attachment cylinder 18 on the abdominal surface 13a side of the second arm 13. The front guard 21 protects the attachment cylinder 18 from pieces of the object to be dismantled (e.g., a ceiling, a wall) dismantled by the cutter 14.

[0037] The pair of side guards 22 are disposed opposite the attachment cylinder 18 in the left-right direction. Below, the configuration of the side guard 22 located to the left of the attachment cylinder 18 will be described, but the configuration of the side guard 22 located to the right of the attachment cylinder 18 is also similar. As shown in Figures 8 and 9, the side guard 22 has a plurality of plates 23, 24, 25, 26, 27, 28, 29, and 30. The number of plates 23 to 30 is not limited to eight.

[0038] The plates 23 to 30 have a long, plate-like shape. The plates 23 to 30 are connected in a state where adjacent plates partially overlap each other. The plates 23 to 30 are connected to be relatively rotatable about the pin 19c (the rotation center of the second link rod 19b). The plates 23 to 30 rotate relatively to each other so that the amount of overlap increases or decreases according to the expansion and contraction of the attachment cylinder 18 (in other words, the rotation of the second link rod 19b). Hereinafter, the circumferential direction of a circle centered on the pin 19c on a plane perpendicular to the extension direction of the pin 19c (i.e., the direction of the arrow in Figures 8 and 9) is referred to as the "rotation direction of the plates 23 to 30".

[0039] The length of each of the plates 23 to 30 is set to be longer than the length of the attachment cylinder 18 when fully extended. The longitudinal direction of the plate 30 is arranged along the longitudinal direction of the attachment cylinder 18. The width of the plates 23 to 30 is greater than the diameter of the attachment cylinder 18. The width of the plate 23 is smaller toward the rotation base end side (i.e., the pin 19c side) and larger toward the rotation tip end side. However, the specific shapes of the plates 23 to 30 are not limited to the examples in FIGS. 5 to 9.

[0040] 5, of the multiple plates 23 to 30, plate 23 at one end in the rotation direction is fixed (for example, welded) to front guard 21. That is, plate 23 is indirectly fixed to second link rod 19b on the abdominal surface 13a side of second arm 13 relative to pin 19c. Plate 23 rotates in the rotation direction together with second arm 13 and front guard 21 about pin 19c.

[0041] As shown in Fig. 6, guide holes 24a and 24b are formed in the plate 24. The guide holes 24a and 24b penetrate the plate 24 in the thickness direction. The guide hole 24a extends in the rotation direction. The guide holes 24a and 24b are formed at positions with different distances from the pin 19c. That is, the guide holes 24a and 24b are formed along parts of the circumference of a concentric circle centered on the pin 19c.

[0042] Furthermore, protrusions 24c and 24d are provided on plate 24. Protrusions 24c and 24d are provided on extensions of guide holes 24a and 24b in the rotation direction. Protrusions 24c and 24d protrude in the thickness direction from the surface of plate 24 toward adjacent plate 25. Protrusions 24c and 24d have a cylindrical outer shape with a size (diameter) that allows them to be inserted into guide holes 25a and 25b of plate 25.

[0043] 6, guide holes 23a, 23b, 25a, and 25b are formed in plates 23 and 25 adjacent to plate 24, and protrusions 23c, 23d, 25c, and 25d are provided in the plates. The other plates 26, 27, 28, 29, and 30 have the same configuration.

[0044] The two adjacent plates 24, 25 are connected to each other so as to be capable of relative rotation by guide holes 25a, 25b of plate 25 (one plate), protrusions 24c, 24d of plate 24 (the other plate), spacers 24e, 24f, and anti-slip pins 24g, 24h (anti-slip members).

[0045] The spacers 24e and 24f have a ring-shaped outer shape with an inner diameter larger than the outer diameter of the protrusions 24c and 25d and an outer diameter larger than the opening width of the guide holes 25a and 25b. The thickness of the spacers 24e and 24f is set to be shorter than the protruding length of the protrusions 24c and 24d. The spacers 24e and 24f are extrapolated onto the protrusions 24c and 24d.

[0046] The projections 24c, 24d with the spacers 24e, 24f fitted thereon are inserted into the guide holes 25a, 25b. At this time, the spacers 24e, 24f are interposed between the plates 24, 25 without passing through the guide holes 25a, 25b. That is, the plates 24, 25 overlap each other with a space therebetween of the thickness of the spacers 24e, 24f.

[0047] The retaining pins 24g and 24h are detachably attached to the tip ends of the projections 24c and 24d that have passed through the guide holes 25a and 25b. More specifically, the projections 24c and 24d have through holes that penetrate radially through the projections 24c and 24d at positions that pass through the guide holes 25a and 25b. The retaining pins 24g and 24h are inserted into the through holes of the projections 24c and 24d that have passed through the guide holes 25a and 25b.

[0048] This mutually connects the adjacent plates 24, 25. Furthermore, the projections 24c, 24d move along the guide holes 25a, 25b, thereby rotating the plates 24, 25 relative to each other. However, the method of connecting the two adjacent plates 24, 25 to be capable of rotating relative to each other is not limited to the above-mentioned example.

[0049] Similarly, the plates 23 and 24 are connected to each other so as to be capable of rotating relative to each other by inserting the projections 23c and 23d, onto which the spacers 23e and 23f are inserted, into the guide holes 24a and 24b, and attaching the retaining pins 23g and 23h to the projections 23c and 23d that have passed through the guide holes 24a and 24b. The same is true for the other adjacent plates 25&26, 26&27, 27&28, 28&29, and 29&30.

[0050] As shown in FIG. 7, of the multiple plates 23 to 30, the plate 30 at the other end in the rotation direction is fixed to the second arm 13. More specifically, a bracket 31 is fixed (for example, welded) to the abdominal surface 13a of the second arm 13. The bracket 31 has a pair of pillars 32, 33 protruding from positions spaced apart in the extension direction of the second arm 13. A projection 30c of the plate 30 is inserted between the pair of pillars 32, 33. Then, a beam member 34 is fixed to the tips of the pillars 32, 33 with bolts, thereby fixing the plate 30 to the second arm 13. However, the method of fixing the plate 30 to the second arm 13 is not limited to the above example.

[0051] As shown in FIG. 8, when the attachment cylinder 18 is contracted, the second link rod 19b rotates counterclockwise around the pin 19c, and the front guard 21 also rotates counterclockwise. As a result, the plate 23 fixed to the front guard 21 also rotates in a direction approaching the plate 30 (in other words, the abdominal surface 13a of the second arm 13). Then, the protrusions 23c and 23d of the plate 23 reach the sides of the guide holes 24a and 24b of the plate 24 that are closer to the plate 30, and push the plate 24 toward the plate 30. As a result, the plate 24 also rotates in a direction approaching the plate 30. Furthermore, the plates 25 to 29 also rotate in a direction approaching the plate 30. As a result, the plates 23 to 30 rotate relatively to the adjacent plates 23 to 30 so that the overlapping amount between the plates 23 to 30 increases.

[0052] On the other hand, as shown in FIG. 9, when the attachment cylinder 18 is extended, the second link rod 19b rotates clockwise around the pin 19c, and the front guard 21 also rotates clockwise. As a result, the plate 23 fixed to the front guard 21 also rotates in a direction away from the plate 30 (in other words, the abdominal surface 13a of the second arm 13). Then, the protrusions 23c and 23d of the plate 23 reach the sides of the guide holes 24a and 24b of the plate 24 that are far from the plate 30, and push the plate 24 to the opposite side to the plate 30. As a result, the plate 24 also rotates in a direction away from the plate 30. Furthermore, the plates 25 to 29 also rotate in a direction away from the plate 30. As a result, the plates 23 to 30 rotate relatively to the adjacent plates 23 to 30 so that the amount of overlap between the plates 23 to 30 decreases.

[0053] 8 and 9, the side of the attachment cylinder 18 is covered by the side guard 22 regardless of the position of the cutter 14 relative to the second arm 13. This makes it possible to prevent the side of the attachment cylinder 18 from coming into contact with the obstacles even when the upper rotating body 3 is rotated when dismantling work is performed in a narrow space surrounded by obstacles.

[0054] Furthermore, according to the above embodiment, by interposing the front guard 21 between the cutter 14 and the attachment cylinder 18 on the abdominal surface 13a side of the second arm 13, it is possible to prevent pieces of the object to be dismantled (e.g., a ceiling or a wall) dismantled by the cutter 14 from contacting the attachment cylinder 18. However, the front guard 21 can be omitted.

[0055] Furthermore, according to the above embodiment, the front guard 21 is used as a bracket for fixing the plate 23 to the second link rod 19b. This makes it possible to support the side of the plate 23 closer to the rotation tip, compared to the case where the plate 23 is directly fixed to the second link rod 19b, and therefore allows the plate 23 to rotate stably.

[0056] Furthermore, plates 23-30 need to be replaced if they come into contact with an obstacle around the work machine 1 and are damaged. Therefore, according to the above embodiment, adjacent plates 24, 25 are connected using guide holes 25a, 25b, projections 24c, 24d, spacers 24e, 24f, and retaining pins 24g, 24h, so that plates 24, 25 can be easily attached and detached. In other words, damaged plates 24, 25 can be easily replaced. The same applies to the other plates 23, 26-30.

[0057] Furthermore, according to the above embodiment, two guide holes 25a, 25b are provided in plate 25, so that plate 24 can rotate smoothly relative to plate 25. The number of guide holes 25a, 25b provided in plate 25 is not limited to two, and may be one, or three or more. The same applies to the other plates 23, 24, 26 to 30.

[0058] The above-described embodiments are illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the gist of the present invention. [Explanation of symbols]

[0059] 1. Work Machinery 2 Undercarriage 3. Upper rotating body 5 Swivel Frame 6 Counterweight 7 Cab 8. Crawler 10 Front work machine 11. Boom 12 First Arm 13 Second Arm 13a ventral surface 13b Back 13c Left side 14 Cutter 14a Mounting bracket 14b Swivel motor 14c,14d blade 14e, 14f Hydraulic cylinder 14g,14h,19c,19d,19e Pin 15 Boom cylinder 16 First arm cylinder 17 Second arm cylinder 18 Attachment cylinder 18a Cylinder tube 18b Cylinder rod 18c Cap 19 Link mechanism 19a First link rod 19b Second link rod 20 Cylinder guard 21 Front guard 22 Side guard 23~30 Plate 23a, 23b, 24a, 24b, 25a, 25b Guide holes 23c,23d,24c,24d,25c,25d,30c protrusion 23e, 23f, 24e, 24f, 25e, 25f Spacer 23g, 23h, 24g, 24h Anti-slip pin (anti-slip member) 31 Bracket 32,33 Pillar part 34 Beam member

Claims

1. A lower running body; An upper rotating body rotatably supported on the lower traveling body; a front working machine that is supported by the upper rotating body and operates, The front working machine is A boom supported on the upper rotating body so as to be capable of being raised and lowered; An arm rotatably supported at the tip of the boom; an attachment rotatably supported at a tip of the arm; an attachment cylinder that expands and contracts by supplying and discharging hydraulic oil; a link mechanism that dumps the attachment when the attachment cylinder is extended and that crowds the attachment when the attachment cylinder is contracted, The arm is A pair of side surfaces facing each other in a width direction of the front working machine; a ventral surface that is connected to the ends of the pair of side surfaces and faces the boom when the arm is folded toward the boom; a back surface connected to the end portions of the pair of side surfaces and facing the abdominal surface in a direction perpendicular to the width direction of the front working machine, The attachment cylinder is disposed on the ventral surface side of the arm, The link mechanism includes: a first link rod having one end rotatably connected to the attachment on the rear side of the arm; a second link rod that is rotatably supported on the side surface of the arm, has one end that protrudes toward the back surface side of the arm and is rotatably connected to the other end of the first link rod, and has the other end that protrudes toward the ventral surface side of the arm and is rotatably connected to the attachment cylinder, a side guard having a plurality of plates connected to each other and relatively rotatable about a rotation center of the second link rod such that an overlapping amount between the plates increases and decreases in response to rotation of the second link rod, the side guard being disposed opposite the attachment cylinder in a width direction of the front working machine, a second link rod having a first end and a second end connected to each other, the second link rod being disposed on the second end of the first link rod and the second link rod being disposed on the second end of the first link rod, the second link rod being disposed on the second end of the first link rod and the second link rod being disposed on the second end of the first link rod.

2. 2. The work machine according to claim 1, a front guard fixed to the other end of the second link rod and interposed between the attachment and the attachment cylinder on the ventral side of the arm.

3. 3. The work machine according to claim 2, A work machine, characterized in that the plate at one end in the rotation direction is fixed to the front guard.

4. 2. The work machine according to claim 1, Each of the two adjacent plates of the side guard is a guide hole penetrating one of the plates in a thickness direction and extending in the rotation direction; a protrusion protruding from the other plate in a thickness direction and inserted into the guide hole; a spacer that is fitted onto the protrusion and is interposed between two adjacent plates; a retaining member that is removably attached to the tip side of the protrusion that passes through the guide hole and prevents the protrusion from coming out of the guide hole, and is connected to the protrusion so as to be capable of rotating relative to the guide hole.

5. 5. The working machine according to claim 4, a second link rod that is disposed in a first direction and a second direction in a direction perpendicular to the first direction of the second link rod;

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