Working machinery

Abstract

To provide a work machine comprising a cylinder cover preventing rattling of a guard plate and allowing a guard plate to slide smoothly.SOLUTION: A work machine includes a vehicle body, a work device supported by the vehicle body, a hydraulic cylinder operating the work device by extending and retracting a cylinder rod out of and into a cylinder tube, and a cylinder cover protecting the hydraulic cylinder. The cylinder cover comprises: a long, plate-like guard plate attached to a tip of the cylinder rod and sliding as the cylinder rod is extended and retracted; a fixed-side receiving member fixed to the cylinder tube and being in sliding contact with one side surface in a thickness direction of the sliding guard plate; a movable-side receiving member supported by the fixed-side receiving member at an opposite side to the fixed-side receiving member across the guard plate so as to be movable in a thickness direction of the guard plate and being in sliding contact with the other side surface in the thickness direction of the sliding guard plate; and an energizing member energizing the movable-side receiving member against the guard plate.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a working machine provided with a cylinder cover.

Background Art

[0002] Conventionally, a working machine including a vehicle body and a front working machine that operates by expansion and contraction of a hydraulic cylinder has been known. In such a working machine, when the exposed hydraulic cylinder comes into contact with earth and sand, rocks, or other obstacles at the work site, the hydraulic cylinder may be deformed and unable to expand and contract, or the oil seal may be damaged, resulting in oil leakage.

[0003] In order to solve such problems, Patent Document 1 discloses a cylinder protection device including a flat plate-shaped guard member attached to a cylinder rod and a slide guide attached to a cylinder tube for housing the guard member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the cylinder protection device of Patent Document 1, if the gap between the slide guide and the guard member is made too wide, the guard member will rattle due to vibrations of the working machine or the like. On the other hand, if the gap between the slide guide and the guard member is made too narrow, smooth sliding of the guard member will be hindered.

[0006] The present invention has been made in view of the above-described actual situation, and an object thereof is to provide a working machine provided with a cylinder cover that prevents rattling of a guard plate and enables the guard plate to slide smoothly.

Means for Solving the Problems

[0007] To achieve the above objective, the present invention provides a work machine comprising a vehicle body, a work device supported by the vehicle body, a hydraulic cylinder that operates the work device by a cylinder rod extending and retracting relative to a cylinder tube, and a cylinder cover that protects the hydraulic cylinder, wherein the cylinder cover comprises: a long plate-shaped guard plate attached to the tip of the cylinder rod and sliding as the cylinder rod extends and retracts; a fixed-side receiving member fixed to the cylinder tube and sliding against one side surface of the sliding guard plate in the thickness direction; a movable-side receiving member supported by the fixed-side receiving member on the opposite side of the guard plate from the fixed-side receiving member, so as to be movable in the thickness direction of the guard plate, and sliding against the other side surface of the sliding guard plate in the thickness direction; and a biasing member that biases the movable-side receiving member against the guard plate. [Effects of the Invention]

[0008] According to the present invention, it is possible to obtain a work machine equipped with a cylinder cover that prevents rattling of the guard plate and allows the guard plate to slide smoothly. Other problems, configurations, and effects will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of the work machine. [Figure 2] This is a perspective view of the arm cylinder and cylinder cover. [Figure 3] This is a disassembled perspective view of the cylinder cover. [Figure 4] This is a cross-sectional view of the cylinder cover guard plate perpendicular to the width direction. [Figure 5] This is a cross-sectional view perpendicular to the sliding direction of the cylinder cover guard plate. [Figure 6] This figure shows the support pin related to Modification 1. [Figure 7]This figure shows a sliding contact block according to modified example 2. [Figure 8] This figure shows a sliding contact block according to modified example 3. [Figure 9] This is a cross-sectional view of a cylinder cover including a biasing member according to modified example 4. [Figure 10] This is a longitudinal cross-sectional view of a cylinder cover including a biasing member according to modified example 4. [Modes for carrying out the invention]

[0010] Embodiments of the work machine 1 according to the present invention will be described with reference to the drawings. Note that the work machine 1 is not limited to the example in Figure 1, and may be any machine equipped with a work device that operates by the extension and retraction of a hydraulic cylinder, such as a hydraulic excavator, wheel loader, or crane. Furthermore, unless otherwise specified, the terms front, back, left, and right in this specification refer to the viewpoint of the operator riding and operating the work machine 1.

[0011] Figure 1 is a side view of the work machine 1. As shown in Figure 1, 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 and the upper rotating body 3 are examples of vehicle bodies.

[0012] The lower undercarriage 2 is equipped with a pair of crawlers 4, which are continuous tracks. Driven by the travel motor 5, the pair of crawlers 4 rotate independently. As a result, the work machine 1 moves. However, the lower undercarriage 2 may be wheeled instead of having crawlers 4.

[0013] The upper slewing body 3 is supported by the lower traveling body 2 so as to be rotatable by a slewing device 6. That is, the upper slewing body 3 rotates relative to the lower traveling body 2 by the drive of a slewing motor provided in the slewing device 6. The upper slewing body 3 mainly consists of a base slewing frame 7, a cab (driver's seat) 8 located on the front left side of the slewing frame 7, a counterweight 9 located at the rear of the slewing frame 7, a front work implement 10 (working device) mounted on the front center of the slewing frame 7 so as to be rotatable in the vertical direction, and a cylinder cover 20.

[0014] The front working machine 10 includes a boom 11 supported on the upper swing body 3 so as to be able to rise and fall, an arm 12 supported at the tip of the boom 11 so as to be able to rotate (crowd, dump), an attachment 13 supported at the tip of the arm 12 so as to be able to rotate (crowd, dump), a boom cylinder 14 for driving the boom 11, an arm cylinder 15 for driving the arm 12, and an attachment cylinder 16 for driving the attachment 13. The specific examples of the attachment are not particularly limited, and for example, a bucket, a grapple, a cutter, a crusher, a breaker, etc. may be used. The counterweight 9 is for taking a weight balance with the front working machine 10 and is a heavy object having an arc shape in a top view.

[0015] The cab 8 is arranged adjacent to the front working machine 10 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 10. However, the arrangement of the cab 8 is not limited to the above example, and the cab 8 may be arranged on one side of the front working machine 10 in the left-right direction.

[0016] An internal space for an operator to operate the work machine 1 is formed in the cab 8. Inside the cab 8, a seat for the operator to sit on and an operating device operated by the operator sitting on the seat are installed. The operating device receives the operation of the operator for operating the work machine 1. When the operating device is operated by the operator, the lower traveling body 2 travels, the upper swing body 3 swings, and the front working machine 10 operates. Specific examples of the operating device include a lever, a steering wheel, a pedal, a switch, etc.

[0017] Figure 2 is a perspective view of the arm cylinder 15 and the cylinder cover 20. As shown in Figure 2, the arm cylinder 15 is an example of a hydraulic cylinder including a cylindrical cylinder tube 15a and a cylinder rod 15b that protrudes and retracts with respect to the cylinder tube 15a. Then, as shown in Figure 1, the arm cylinder 15 is attached to the ventral side of the boom 11 and the arm 12 by the proximal end of the cylinder tube 15a being rotatably supported by the boom 11 and the distal end of the cylinder rod 15b being rotatably supported by the arm 12.

[0018] As shown in FIGS. 2(A) and 2(B), when hydraulic oil is supplied to and discharged from the arm cylinder 15, the cylinder rod 15b protrudes and retracts with respect to the cylinder tube 15a (that is, the arm cylinder 15 expands and contracts). Further, as shown in FIG. 2(A), the cylinder rod 15b protruding from the cylinder tube 15a is in an exposed state. Therefore, as shown in FIG. 1, the cylinder cover 20 is disposed on the opposite side of the boom 11 and the arm 12 across the arm cylinder 15 so as to protect the exposed cylinder rod 15b. Note that the hydraulic cylinder protected by the cylinder cover 20 is not limited to the arm cylinder 15, and may be a boom cylinder 14, an attachment cylinder 16, or the like.

[0019] Figure 3 is an exploded perspective view of the cylinder cover 20. Figure 4 is a cross-sectional view orthogonal to the width direction of the guard plate 23 of the cylinder cover 20. Figure 5 is a cross-sectional view orthogonal to the sliding direction of the guard plate 23 of the cylinder cover 20. As shown in Figure 3, the cylinder cover 20 mainly includes a rotating bracket 21, a fixed bracket 22, a guard plate 23, a fixed-side receiving member 24, a movable-side receiving member 25, and a pair of coil springs 26L and 26R (biasing members).

[0020] The rotating bracket 21 is rotatably supported at the distal end portion of the cylinder rod 15b. Further, the rotating bracket 21 supports one end in the longitudinal direction of the guard plate 23. That is, the guard plate 23 is rotatably attached to the distal end portion of the cylinder rod 15b via the rotating bracket 21.

[0021] The fixing bracket 22 is supported by the cylinder tube 15a. The fixing bracket 22 also supports the fixed-side receiving member 24. That is, the fixed-side receiving member 24 is fixed to the cylinder tube 15a via the fixing bracket 22. The fixing bracket 22 comprises, for example, a semicircular first bracket 22a and a second bracket 22b that are mounted to cover the outer circumferential surface of the cylinder tube 15a.

[0022] The guard plate 23 is a long, plate-shaped member. One end of the guard plate 23 in the longitudinal direction is fixed to the rotating bracket 21. The guard plate 23 is mounted with its longitudinal direction facing the direction in which the cylinder rod 15b extends and retracts (the direction in which the arm cylinder 15 extends and retracts). Furthermore, the other end of the guard plate 23 in the longitudinal direction is slidably supported (clamped) by the fixed-side receiving member 24 and the movable-side receiving member 25. The guard plate 23 slides in conjunction with the extension and retraction of the cylinder rod 15b. The sliding direction of the guard plate 23 coincides with the longitudinal direction of the guard plate 23, the direction in which the cylinder rod 15b extends and retracts, and the direction in which the arm cylinder 15 extends and retracts.

[0023] Furthermore, as shown in Figures 4 and 5, the guard plate 23 has a first surface 23a on one side in the thickness direction and a second surface 23b on the other side in the thickness direction. The guard plate 23 is provided with reinforcing ribs 23c that protrude from the first surface 23a and extend in the direction of extension of the guard plate 23. However, the reinforcing ribs 23c are not limited to one, but may be provided at two locations spaced apart in the width direction of the guard plate 23. Also, the reinforcing ribs 23c are optional.

[0024] The fixed-side receiving member 24, while fixed to the cylinder tube 15a, slides against the first surface 23a of the sliding guard plate 23, guiding the sliding of the guard plate 23. The fixed-side receiving member 24 mainly comprises a base 241, a pair of sliding contact plates 242L and 242R, and a pair of support brackets 243L and 243R.

[0025] The base 241 has a generally flat plate shape. One side of the base 241 in the thickness direction is fixed to the fixing bracket 22, and the other side in the thickness direction supports a pair of sliding contact plates 242L, 242R and a pair of support brackets 243L, 243R. In this embodiment, an example is described in which the fixed-side receiving member 24 is composed of three types of parts (base 241, sliding contact plates 242L, 242R, and support brackets 243L, 243R), but all or part of them (for example, the base 241 and support brackets 243L, 243R) may be integrally molded.

[0026] The pair of sliding contact plates 242L and 242R have a generally rectangular shape. The pair of sliding contact plates 242L and 242R are fixed to the surface of the base 241 facing the guard plate 23. More specifically, the pair of sliding contact plates 242L and 242R are positioned spaced apart in the width direction of the guard plate 23, with their longitudinal direction oriented in the sliding direction of the guard plate 23. As shown in Figure 5, the pair of sliding contact plates 242L and 242R slide against the first surface 23a of the sliding guard plate 23 on both sides of the reinforcing rib 23c in the width direction of the guard plate 23. The pair of sliding contact plates 242L and 242R are made of, for example, wear-resistant resin to reduce sliding resistance with the guard plate 23.

[0027] As shown in Figure 4, the sliding contact plate 242R has a sliding contact surface 244 and a pair of guide surfaces 245F and 245B. The sliding contact surface 244 is a plane that slides against the first surface 23a of the guard plate 23. The pair of guide surfaces 245F and 245B are provided at the front and rear ends of the sliding contact surface 244 (i.e., on both sides of the sliding contact surface 244 in the sliding direction of the guard plate 23). Each of the pair of guide surfaces 245F and 245B is an inclined surface that is tilted in a direction in which the distance from the guard plate 23 increases as it moves away from the sliding contact surface 244. The guide surfaces 245F and 245B may be formed, for example, by chamfering both ends of the sliding contact surface 244 with a C-chamfer or R-chamfer.

[0028] A pair of support brackets 243L and 243R are fixed to the base 241 on both sides of the guard plate 23 in the width direction. That is, the pair of support brackets 243L and 243R are positioned opposite each other on either side of the guard plate 23 in the width direction. Furthermore, the pair of support brackets 243L and 243R extend from the base 241 to the side opposite the arm cylinder 15 (i.e., the side of the guard plate 23 and the movable side receiving member 25). In addition, the support brackets 243L and 243R have elongated holes 246L and 246R that are long in the thickness direction of the guard plate 23.

[0029] The support bracket 243R has a generally crank-shaped (Z-shaped) outer form. More specifically, the support bracket 243R comprises a support portion 247R extending in the thickness direction of the guard plate 23, a fixed portion 248R bent in the thickness direction of the support portion 247R from the end of the support portion 247R on the base 241 side, and a covering portion 249R bent in the opposite direction to the fixed portion 248R from the end of the support portion 247R opposite to the base 241. An elongated hole 246R is formed in the support portion 247R. The fixed portion 248R is attached to the base 241. Furthermore, the covering portion 249R covers the coil springs 26L, 26R. The shape of the support bracket 243L is similar.

[0030] The movable side receiving member 25 is positioned on the opposite side of the fixed side receiving member 24 (more specifically, the sliding contact plates 242L and 242R) with the guard plate 23 in between. The movable side receiving member 25 is also supported by the fixed side receiving member 24 (more specifically, a pair of support brackets 243L and 243R) so as to be movable in the thickness direction of the guard plate 23. Furthermore, the movable side receiving member 25 slides against the second surface 23b of the guard plate 23 to guide the sliding of the guard plate 23. The movable side receiving member 25 mainly comprises a sliding contact block 251 (sliding contact member) and a support pin 252 (supported member).

[0031] The sliding contact block 251 is positioned on the opposite side of the sliding contact plates 242L and 242R, with the guard plate 23 in between. That is, the sliding contact block 251 is positioned facing the second surface 23b of the guard plate 23. The sliding contact block 251 then slides against the second surface 23b of the sliding guard plate 23. The sliding contact block 251 is made of, for example, a wear-resistant resin to reduce sliding resistance with the guard plate 23. In addition, the sliding contact block 251 has a through hole 253 that penetrates through the width direction of the guard plate 23.

[0032] Furthermore, as shown in Figure 4, the sliding contact block 251 has a sliding contact surface 254 and a pair of guide surfaces 255F and 255B. The sliding contact surface 254 is a plane that slides against the second surface 23b of the guard plate 23. The pair of guide surfaces 255F and 255B are provided at the front and rear ends of the sliding contact surface 254 (i.e., on both sides of the sliding contact surface 254 in the sliding direction of the guard plate 23). Each of the pair of guide surfaces 255F and 255B is an inclined surface that is tilted in a direction in which the distance from the guard plate 23 increases as it moves away from the sliding contact surface 254. The guide surfaces 255F and 255B may be formed, for example, by chamfering both ends of the sliding contact surface 254 with a C-chamfer or R-chamfer.

[0033] The support pin 252 is a round bar with a perfectly circular cross-section. The support pin 252 is inserted through a through hole 253 in the sliding contact block 251, with both ends protruding from the sliding contact block 251. Furthermore, each end of the support pin 252 protruding from the sliding contact block 251 is inserted into a pair of elongated holes 246L and 246R, thereby being supported by a pair of support brackets 243L and 243R. As a result, the support pin 252 moves along the elongated holes 246L and 246R in the thickness direction of the guard plate 23 while supporting the sliding contact block 251. In other words, the sliding contact block 251 is supported by the pair of support brackets 243L and 243R via the support pin 252 in a state that allows it to move in the thickness direction of the guard plate 23.

[0034] A pair of coil springs 26L and 26R bias the movable receiving member 25 (more specifically, the sliding contact block 251) toward the second surface 23b of the guard plate 23. As a result, the fixed receiving member 24 and the movable receiving member 25 (more specifically, the sliding contact plates 242L, 242R and the sliding contact block 251) clamp the guard plate 23 with appropriate pressure.

[0035] Each of the pair of coil springs 26L and 26R is connected to the fixed-side receiving member 24 and the movable-side receiving member 25 in an extended state compared to its natural state. The pair of coil springs 26L and 26R then bias the movable-side receiving member 25 against the guard plate 23 with a force that tries to return them to their natural state (i.e., a contraction force).

[0036] More specifically, the pair of coil springs 26L and 26R are positioned on both sides of the guard plate 23 in the width direction. Furthermore, one end of each coil spring 26L and 26R is fixed to the base 241, and the other end is attached to the support pin 252. As a result, the pair of coil springs 26L and 26R independently bias the sliding contact block 251 against the guard plate 23 on both sides of the guard plate 23 in the width direction.

[0037] Furthermore, each component of the cylinder cover 20 is attached detachably by bolts or the like. Specifically, the sliding contact plates 242L and 242R are detachably supported on the base 241. Similarly, the sliding contact block 251 is detachably supported on the support pin 252. In other words, the sliding contact plates 242L and 242R and the sliding contact block 251 are configured to be replaceable. However, the method of attaching each component of the cylinder cover 20 is not limited to bolts; welding, rivets, etc., may also be used.

[0038] According to the above embodiment, for example, the following effects are achieved.

[0039] According to the above embodiment, by biasing the movable receiving member 25 against the guard plate 23, the guard plate 23 can be clamped with appropriate pressure by the fixed receiving member 24 and the movable receiving member 25. This prevents the guard plate 23 from rattling due to vibrations during the operation of the work machine 1. On the other hand, even if the guard plate 23 is plastically deformed by an external force, the pressure applied by the fixed receiving member 24 and the movable receiving member 25 is adjusted by the coil springs 26L and 26R, allowing the guard plate 23 to slide smoothly.

[0040] In addition to the form of curving in the longitudinal direction, a specific example of plastic deformation of the guard plate 23 is also a form of twisting around the longitudinal axis. Therefore, according to the above embodiment, the movable side receiving member 25 is biased against the guard plate 23 by a pair of coil springs 26L and 26R that expand and contract independently on both sides in the width direction of the guard plate 23, so that even if the guard plate 23 twists, the pressing force by the fixed side receiving member 24 and the movable side receiving member 25 can be appropriately adjusted.

[0041] Furthermore, according to the above embodiment, by providing guide surfaces 245F, 245B, 255F, and 255B on both sides of the sliding contact surfaces 244 and 254, it is possible to prevent the sliding guard plate 23 from getting caught on the sliding contact plates 242L, 242R or the sliding contact block 251. As a result, the sliding of the guard plate 23 becomes even smoother.

[0042] Furthermore, according to the above embodiment, by configuring the sliding contact plates 242L, 242R and sliding contact block 251 to be detachable, the sliding contact plates 242L, 242R and sliding contact block 251 that have worn down due to sliding contact with the guard plate 23 can be easily replaced. This reduces the downtime of the work machine 1 compared to replacing the entire cylinder cover 20, and also contributes to reducing waste.

[0043] Furthermore, according to the above embodiment, the strength of the guard plate 23 is improved by providing reinforcing ribs 23c to the guard plate 23. This prevents plastic deformation of the guard plate 23 that exceeds the adjustment capacity of the coil springs 26L and 26R.

[0044] The specific configuration of the cylinder cover 20 is not limited to the examples described above. Hereinafter, modifications 1 to 4 of the cylinder cover 20 according to the above embodiment will be described with reference to Figures 6 to 10. Detailed explanations of commonalities with the above embodiment will be omitted, and the differences will be the focus of the explanation. Furthermore, the above embodiment and the following modifications 1 to 4 can be combined in whole or in part without violating the spirit of the present invention.

[0045] [Example 1] Figure 6 shows the support pin 252a according to Modified Example 1. As shown in Figure 6, the support pin 252a according to Modified Example 1 is composed of a pair of parallel parts 256a and 256b that are parallel to each other in a cross section perpendicular to the width direction of the guard plate 23, and a pair of arc parts 257a and 257b that connect the ends of the pair of parallel parts 256a and 256b. In other words, the support pin 252a according to Modified Example 3 corresponds to a shape obtained by cutting a round bar parallel to each other along the axial direction at two points equidistant from the center.

[0046] Furthermore, the distance D1 between the pair of parallel sections 256a and 256b is smaller than the width W in the shorter direction of the elongated holes 246L and 246R (only the elongated hole 246R is shown in Figure 6). On the other hand, the diameter D2 of the virtual circle containing the pair of arc sections 257a and 257b is larger than the width W in the shorter direction of the elongated holes 246L and 246R. As a result, the support pin 252a is inserted into the elongated holes 246L and 246R of the pair of support brackets 243L and 243R, respectively, in a state where it is movable in the thickness direction of the guard plate 23 but cannot rotate around an axis extending in the width direction of the guard plate 23.

[0047] According to Modification 1, the sliding contact block 251 can be prevented from rotating by sliding contact with the sliding guard plate 23. As a result, the sliding contact surface 254 can be stably brought into surface contact with the second surface 23b of the guard plate 23.

[0048] [Differentiation 2] Figure 7 shows a sliding contact block 251a according to Modification 2. As shown in Figure 7, the sliding contact block 251a according to Modification 2 has a sliding contact surface 254a with a circular arc shape in cross-section perpendicular to the width direction of the guard plate 23, instead of the sliding contact surface 254 and guide surfaces 255F and 255B of the sliding contact block 251. That is, the sliding contact surface 254a according to Modification 2 corresponds to a part of the outer surface of the cylinder in the circumferential direction.

[0049] According to Modification 2, the contact area between the guard plate 23 and the sliding contact block 251a is reduced. As a result, the guard plate 23 can slide even more smoothly.

[0050] [Difference 3] Figure 8 shows a sliding contact block 251b according to Modification 3. As shown in Figure 8, the sliding contact block 251b according to Modification 3 is a cylindrical member externally fitted onto a support pin 252. The sliding contact block 251b is supported on a fixed-side receiving member 24 so as to be rotatable around an axis extending in the width direction of the guard plate 23. As an example, the sliding contact block 251b may rotate relative to the support pin 252. As another example, the support pin 252 supporting the sliding contact block 251b may rotate relative to the support brackets 243L and 243R.

[0051] According to Modification 3, the sliding contact block 251b rotates as the guard plate 23 slides. This reduces the contact area and sliding resistance between the guard plate 23 and the sliding contact block 251b. As a result, the guard plate 23 can slide even more smoothly.

[0052] [Differentiation Example 4] Figure 9 is a cross-sectional view of the cylinder cover 20 including the biasing member according to Modification 4. Figure 10 is a longitudinal cross-sectional view of the cylinder cover 20 including the biasing member according to Modification 4. As shown in Figure 9, the cylinder cover 20 according to Modification 4 is equipped with a leaf spring 26 (biasing member) instead of a pair of coil springs 26L and 26R. The support bracket 243 according to Modification 4 is an integral structure that covers the side of the guard plate 23 opposite to the sliding contact plates 242L and 242R. The guard plate 23 is equipped with a sliding plate 23d (another example of a movable side receiving member) made of, for example, wear-resistant resin on the second surface 23b side of the guard plate 23, instead of the movable side receiving member 25. The leaf spring 26 is positioned between the support bracket 243 and the sliding plate 23d in a contracted state from its natural state. As a result, the leaf spring 26 biases the sliding contact plates 242L and 242R to the guard plate 23 by the force that tries to return to its natural state.

[0053] As shown in Modification 4, by using a leaf spring 26 as a biasing member, the cylinder cover 20 can be made smaller in both the thickness and width directions of the guard plate 23 compared to the case where a pair of coil springs 26L and 26R are used.

[0054] The embodiments described above are illustrative for explaining the present invention and are not intended to limit the scope of the invention to those embodiments only. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the invention. [Explanation of symbols]

[0055] 1. Working Machinery 2 Lower running body 3. Upper rotating body 4 Crawler 5. Driving motor 6. Swivel device 7. Swivel Frame 8 Cab 9 Counterweight 10 Front work equipment 11 Boom 12 arms 13 Attachments 14 Boom Cylinder 15 Arm Cylinder 15a Cylinder tube 15b Cylinder rod 16 Attachment Cylinder 20 Cylinder Cover 21 Rotating Bracket 22 Fixing brackets 22a First Bracket 22b Second bracket 23 Guard plate 23a 1st page 23b 2nd side 23c Reinforcement Rib 23d Sliding plate (movable side receiving member) 24 Fixed side receiving member 25 Movable side receiving member 26 Leaf springs 26L, 26R Coil Springs 241 base 242L, 242R sliding contact plates 243, 243L, 243R Support Brackets 244,254,254a Sliding surface 245B, 245F, 255B, 255F Guide surface 246L,246R long hole 247R Support part 248R Fixed part 249R Covering 251, 251a, 251b sliding contact blocks 252,252a Support pins 253 Through hole 256a,256b Parallel part 257a, 257b Arc section

Claims

1. A work machine comprising a vehicle body, a work device supported by the vehicle body, a hydraulic cylinder that operates the work device by a cylinder rod extending and retracting in and out of a cylinder tube, and a cylinder cover that protects the hydraulic cylinder, The cylinder cover is A long, plate-shaped guard plate is attached to the tip of the cylinder rod and slides as the cylinder rod extends and retracts, A fixed receiving member is fixed to the cylinder tube and slides against one side of the thickness direction of the sliding guard plate, On the side opposite the fixed receiving member, with the guard plate in between, a movable receiving member is supported by the fixed receiving member so as to be movable in the thickness direction of the guard plate, and slides against the other side surface of the sliding guard plate in the thickness direction, A work machine characterized by comprising a biasing member that biases the movable side receiving member toward the guard plate.

2. In the work machine described in claim 1, The biasing member is a pair of coil springs connected to the fixed-side receiving member and the movable-side receiving member on both sides in the width direction of the guard plate, in an extended state from its natural state, and biasing the movable-side receiving member to the guard plate with a force that attempts to return to the natural state.

3. In the work machine described in claim 1, The fixed-side receiving member and the movable-side receiving member are, A sliding contact surface that slides against the guard plate, A working machine characterized by having a pair of guide surfaces on both sides of the sliding contact surface of the guard plate in the sliding direction, which are inclined in a direction that increases the distance from the guard plate as it moves away from the sliding contact surface.

4. In the work machine described in claim 3, The fixed-side receiving member has a pair of support portions on both sides of the guard plate in the width direction, each having an elongated hole extending in the thickness direction of the guard plate. The working machine is characterized in that the movable side receiving member has a supported member inserted through the elongated holes of each of the pair of support parts, such that it is movable in the thickness direction of the guard plate and cannot rotate around an axis extending in the width direction of the guard plate.

5. In the work machine described in claim 1, The movable side receiving member is characterized in that its cross-section perpendicular to the width direction of the guard plate is arc-shaped and has a sliding contact surface that slides against the sliding guard plate.

6. In the work machine described in claim 1, The movable side receiving member is supported by the fixed side receiving member so as to be rotatable about an axis extending in the width direction of the guard plate, and has a cylindrical member that rotates in sliding contact with the sliding guard plate.

7. In the work machine described in claim 1, The aforementioned movable side receiving member is A supported member is supported by the fixed receiving member so as to be movable in the thickness direction of the guard plate, A work machine characterized by comprising a sliding contact member that is detachably supported by the supported member and slides against the sliding guard plate.

8. In the work machine described in claim 1, The work machine is characterized in that the guard plate protrudes toward the fixed-side receiving member from the surface facing the fixed-side receiving member and has reinforcing ribs extending in the sliding direction of the guard plate.

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