Working machinery

Abstract

In a work machine having a tilt floor configured to be tiltable up and tiltable down, the torsional force of the torsion bar is adjusted as appropriate. [Solution] The shovel 100 has a main body 1 including at least a work implement 10, and a tilt floor 7 disposed on the main body 1, wherein the tilt floor 7 is configured to be tiltable up and down relative to the main body 1. The shovel 100 has a torsion bar 9 having a straight section 9a that generates torsional force, a movable end 9b extending from one end of the straight section 9a and rotatable to tilt the tilt floor 7 up by torsional force, and a fixed end 9c extending from the other end of the straight section 9a and fixed to a fixed frame 12 provided on the main body 1, and a fixed end position adjustment mechanism 20a configured to adjust the position of the fixed end 9c of the torsion bar 9 in a direction intersecting the longitudinal direction of the straight section 9a of the torsion bar 9.

Description

Technical Field

[0001] The present invention relates to a work machine having a tilt floor configured to be tiltable up and down.

Background Art

[0002] Conventionally, in work machines such as hydraulic excavators, in order to secure a space necessary for work such as maintenance and inspection of the inside (engine, etc.), a structure is adopted in which an operator can manually tilt up a tilt floor provided with an operator seat, a cab or a canopy. Further, as a mechanism for assisting the tilting up of such a tilt floor, a torsion bar, a hydraulic cylinder, a gas spring, etc. are used.

[0003] For example, Patent Document 1 discloses a technique for assisting the tilting up of a tilt floor using a torsion bar. This torsion bar includes a straight portion (intermediate portion) that generates torsional force, a movable end (upper edge portion) formed by bending from one end of the straight portion and rotatable so as to tilt up the tilt floor by the torsional force, and a fixed end (lower edge portion) formed by bending from the other end of the straight portion and fixed to the frame.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique disclosed in Patent Document 1 described above, the torsional force of the torsion bar is fixed and cannot be adjusted.

[0006] Therefore, the present invention aims to enable the torsional force of a torsion bar to be appropriately adjusted in a work machine having a tilt floor configured to be tiltable up and tiltable down. [Means for solving the problem]

[0007] In one aspect of the present invention, a work machine having a main body including at least a work machine and a tilt floor disposed on the main body, wherein the tilt floor is configured to be able to tilt up and tilt down relative to the main body, is characterized by having a torsion bar having a straight section that generates a torsional force, a movable end extending from one end of the straight section and in contact with the lower surface of the tilt floor and rotatable to tilt the tilt floor up by torsional force, and a fixed end extending from the other end of the straight section and fixed to a fixed frame provided on the main body, and a fixed end position adjustment mechanism configured to adjust the position of the fixed end of the torsion bar in a direction intersecting the longitudinal direction of the straight section of the torsion bar. [Effects of the Invention]

[0008] According to the above embodiment, in a work machine having a tilt floor configured to be tiltable up and tiltable down, the torsional force of the torsion bar can be adjusted as appropriate, and as a result, it is possible to achieve both tilt-up operation and tilt-down operation of the tilt floor. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of an excavator according to an embodiment of the present invention. [Figure 2] This is a side view showing the tilt floor of an excavator according to an embodiment of the present invention in a tilted-up state. [Figure 3] This is a perspective view of the main part of the tilt floor of an excavator according to an embodiment of the present invention, viewed from below. [Figure 4] This is a side view of the main part below the tilt floor of an excavator according to an embodiment of the present invention. [Figure 5]This is a lower view of the main part below the tilt floor of an excavator according to an embodiment of the present invention. [Figure 6] This is a schematic perspective view illustrating the basic configuration of a torsion bar according to an embodiment of the present invention. [Figure 7] This is a top view of a fixed end position adjustment mechanism according to the first embodiment of the present invention. [Figure 8] This is a partial cross-sectional view along the line VIII-VIII in Figure 7. [Figure 9] This is a perspective view of the main part illustrating the engagement between the contact plate and the guide plate according to the first embodiment of the present invention. [Figure 10] This is a top view of a fixed end position adjustment mechanism according to a second embodiment of the present invention. [Figure 11] This is a partial cross-sectional view along the line XI-XI in Figure 10. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In all drawings used to illustrate the embodiments, the same reference numerals are generally used for the same components, and repeated descriptions of them will be omitted.

[0011] Furthermore, in the following explanation, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," mean not only strictly such arrangements or states, but also include arrangements or states that are relatively displaced by an angle or distance sufficient to achieve tolerances or the same function.

[0012] [Configuration of the work machine] First, referring to FIGS. 1 to 5, the configuration of the working machine according to this embodiment will be described. In this embodiment, as the work vehicle, a small excavator (hydraulic excavator) of about 5 tons or less will be taken as an example. FIG. 1 is a side view of the excavator according to this embodiment, FIG. 2 is a side view showing a state where the tilt floor of the excavator according to this embodiment is tilted up, FIG. 3 is a perspective view of a main part of the excavator according to this embodiment as seen from below the tilt floor, FIG. 4 is a side view of a main part below the tilt floor of the excavator according to this embodiment, and FIG. 5 is a bottom view of a main part below the tilt floor of the excavator according to this embodiment.

[0013] As shown in FIG. 1, the excavator 100 has a main body 1 including a lower traveling body 2 around which a crawler r for moving and traveling is wound, an upper revolving body 3 rotatably disposed above the lower traveling body 2, and a working machine 10 disposed at the front of the upper revolving body 3.

[0014] The working machine 10 has a hydraulically driven boom 10a and arm 10b, and an excavation bucket 10c attached to the tip of the arm 10b. The working machine 10 is pivotally supported so as to be swingable in the vertical direction and is supported so as to be rotatable in the horizontal direction around a support shaft disposed in the vertical direction. Further, a blade b is swingably disposed at the front of the lower traveling body 2. The blade b can perform a predetermined operation as an earth discharge plate when filling back the soil dug up by the bucket 10c.

[0015] Also, above the main body 1, specifically, above the upper revolving body 3, a canopy 4 mainly including a roof 5 for protecting the driver's seat is disposed. Inside the canopy 4, an operator seat 3a on which an operator sits and works is disposed. A plurality of control levers 3b for controlling the operation of the working machine 10 and the traveling of the excavator 100 are disposed around the operator seat 3a.

[0016] The canopy 4 is provided on the tilt floor 7, and the roof 5 is supported and fixed from the lower surface side by a pair of left and right columns 5a and 5b, and the lower ends of the columns 5a and 5b are connected and fixed by the second mounting seat plate 6b. The second mounting seat plate 6b is fixed to the first mounting seat plate 6a to which the exterior panel 3p is fixed.

[0017] An engine (not shown) is housed in the exterior panel 3p below the operator seat 3a. The tilt floor 7 constitutes the floor of the driver's seat and is supported so as to be tilt-rotatable with respect to the revolve frame R of the upper revolving body 3. The revolve frame R includes an outer wall (outer wall frame) formed so as to cover the outer periphery of the upper revolving body 3. In the lower exterior panel 3p1 below the tilt floor 7, hydraulic valves, a swing motor for swinging the upper revolving body 3 with respect to the lower traveling body 2, pipes, etc. are disposed on the revolve frame R. The excavator 100 operates a hydraulic pump by the driving force of the engine and uses the hydraulic pressure output from the hydraulic pump to operate a traveling hydraulic motor and various actuators for driving the working machine 10, etc.

[0018] Subsequently, as shown in FIG. 2, the tilt floor 7 has a stepped shape in a side view, and a floor plate of the operator seat 3a is formed at the front part thereof, and a central vertical wall plate covering the front side of the engine below the operator seat 3a is formed at the central part. And a rear upper wall plate covering the upper part of the engine is formed at the rear part side.

[0019] The tilt floor 7 is pivotally supported with respect to the revolve frame R by a hinge mechanism Rh formed on the revolve frame R at its front end. Thereby, the tilt floor 7 tilts up and tilts down with respect to the revolve frame R with the hinge mechanism Rh as the rotation center.

[0020] In other words, during normal operation or travel using the shovel 100, the tilt floor 7 is tilted down to a closed position, as shown in Figure 1, while performing work with the work equipment and travel operations. On the other hand, when performing inspection or maintenance work on the shovel 100, the tilt floor 7 is tilted up to its fully open position, as shown in Figure 2, while performing inspection or maintenance work. When the tilt floor 7 is tilted down to a closed position, it is held in the closed position by a locking mechanism (not shown). When the tilt floor 7 is tilted up to its fully open position, it is locked in the fully open position by a stopper (not shown).

[0021] In the excavator 100 according to this embodiment, as shown in Figures 2 to 5, a gas spring 8 and a torsion bar 9 are provided to assist the operator in manually tilting up the tilt floor 7. First, the gas spring 8 will be described. The gas spring 8 is disposed between the back surface 7r of the tilt floor 7 and the Revo frame R. Specifically, one end of the gas spring 8 is rotatably supported by a mounting bracket 7r1 fixed to the back surface 7r of the tilt floor 7 (Figure 3). The other end of the gas spring 8 is rotatably supported by a mounting bracket R1 fixed to the Revo frame R (Figures 4 and 5).

[0022] Next, the torsion bar 9 will be described. To explain the torsion bar 9, please refer to Figure 6 in addition to Figures 2 to 5. Figure 6 is a schematic diagram illustrating the basic configuration of the torsion bar 9, and is a perspective view of the torsion bar 9 seen from diagonally above. Note that in Figure 6 (and similarly in Figure 5), detailed illustrations of the fixed end position adjustment mechanism according to this embodiment, which will be described later, are omitted for the sake of simplicity.

[0023] The torsion bar 9 is formed using, for example, spring steel with a diameter of approximately φ21 mm and is disposed between the Revo frame R and the back surface 7r of the tilt floor 7 (Figures 2 to 5). As shown in Figures 5 and 6, the torsion bar 9 has a straight section 9a, a movable end 9b, and a fixed end 9c integrally formed. The straight section 9a extends in the left-right direction of the shovel 100 and is capable of generating torsional force. The movable end 9b is formed by bending in a direction substantially perpendicular to one end of the straight section 9a and is rotatable so as to tilt the tilt floor 7 upward by torsional force. The fixed end 9c is formed by bending in a direction substantially perpendicular to the other end of the straight section 9a and is fixed to the fixed frame 12 provided on the Revo frame R.

[0024] Specifically, as shown in Figure 5, the movable end 9b is located near the inner wall surface of the side wall of the Revo frame R and on one end in the left-right direction, while the fixed end 9c is located near the inner wall surface of the side wall of the Revo frame R and on the other end in the left-right direction. In other words, the movable end 9b and the fixed end 9c are located near roughly opposite ends in the left-right direction inside the Revo frame R. Also, as shown in Figure 6, the fixed end 9c is provided to extend approximately vertically (downward) from the straight section 9a. On the other hand, when the tilt floor 7 is in the closed position tilted down, the movable end 9b extends approximately horizontally (rearward) from the straight section 9a (represented by a solid line in Figure 6). Also, when the tilt floor 7 is in the fully open position tilted up, the movable end 9b extends diagonally upward from the straight section 9a (represented by a dashed line in Figure 6).

[0025] In the closed position where the tilt floor 7 is tilted down, the torsion bar 9 is twisted in the direction indicated by arrow A11, as shown in Figure 6. When this twist returns to its original position, it generates a repulsive force (torsional force) in the direction indicated by arrow A12, thereby assisting in the tilt-up of the tilt floor 7. In particular, the torsion bar 9 is twisted in the straight section 9a, and the torsional force is generated from this straight section 9a. The amount of twist in the straight section 9a is determined according to the position of the end of the straight section 9a, and a torsional force proportional to this amount of twist is generated.

[0026] More specifically, the end of the movable end 9b of the torsion bar 9 is attached to a torsion bar support member 7r2 fixed to the back surface 7r of the tilt floor 7 (Figures 3 to 5). This torsion bar support member 7r2 forms a closed space between itself and the back surface 7r of the tilt floor 7. The end of the movable end 9b is freely movable in the front-rear and up-down directions of the shovel 100 within this closed space formed by the torsion bar support member 7r2.

[0027] The straight portion 9a of the torsion bar 9 is rotatably supported on the Revo frame R via torsion bar mounting members 11a and 11b (Figures 5 and 6). The end of the fixed end 9c of the torsion bar 9 is held by a substantially L-shaped contact plate 13, and is fixed to a fixed frame 12 provided on the Revo frame R via this contact plate 13 (Figures 5 and 6). As will be described in detail later, the contact plate 13 constitutes a fixed end position adjustment mechanism according to this embodiment, and is configured to adjust the position of the fixed end 9c relative to the fixed frame 12 by moving relative to the fixed frame 12.

[0028] [Configuration of the fixed end position adjustment mechanism] Next, the fixed end position adjustment mechanism according to this embodiment, for adjusting the position of the fixed end 9c of the torsion bar 9, will be described. First, before describing the fixed end position adjustment mechanism, the reason for using the fixed end position adjustment mechanism will be explained.

[0029] The torsional force of the torsion bar 9 (the repulsive force generated when the torsion bar is twisted) acts as a force that assists the worker in tilting up the tilt floor 7. However, when the worker finishes working with the tilt floor 7 tilted up and wants to tilt it down, the torsional force of the torsion bar 9 acts as a force that hinders the worker's tilt-down operation of the tilt floor 7. Therefore, the torsional force of the torsion bar 9 assists the tilt-up operation when tilting up the tilt floor 7, but hinders the tilt-down operation when tilting down the tilt floor 7.

[0030] Here, since the canopy 4 and other components mounted on the tilt floor 7 are relatively heavy, it is advisable to set a high torsional force on the torsion bar 9 in order to easily tilt up the tilt floor 7. However, setting a high torsional force on the torsion bar 9 makes tilting up easy, but tends to make tilting down difficult. Conversely, if the torsional force on the torsion bar 9 is set low to make tilting down the tilt floor 7 easy, then tends to make tilting up difficult.

[0031] For these reasons, the torsional force of the torsion bar 9 assists in the tilt-up operation of the tilt floor 7, but hinders the tilt-down operation of the tilt floor 7. Therefore, in order to achieve a balance between these two operational needs, it is desirable to be able to appropriately adjust the torsional force of the torsion bar 9. In other words, it would be ideal if the torsional force of the torsion bar 9 could be adjusted so that it is increased when tilting up the tilt floor 7, and decreased when tilting down the tilt floor 7.

[0032] On the other hand, the torsional force of the torsion bar 9 is set according to the position of the fixed end 9c of the torsion bar 9, particularly the position of the fixed end 9c in a direction substantially perpendicular to the longitudinal direction (left-right direction) of the straight section 9a (front-rear direction) (Figures 5 and 6). This is because the torsion of the straight section 9a is caused by the fixed end 9c, and therefore the amount of torsion of the torsion bar 9 changes depending on the position of this fixed end 9c in the front-rear direction. In the technology disclosed in Patent Document 1 mentioned above, since the position of the fixed end is constant (because the fixed end is fixed to the frame, the position of the fixed end is constant), the torsional force of the torsion bar was fixed to a force corresponding to the position of the fixed end.

[0033] Based on the above, in this embodiment, a fixed end position adjustment mechanism is used that is configured to adjust the position of the fixed end 9c of the torsion bar 9 so as to appropriately change the magnitude of the torsional force of the torsion bar 9. In particular, in this embodiment, the fixed end position adjustment mechanism is used to move the position of the fixed end 9c in a direction that intersects (approximately orthogonal to) the longitudinal direction of the straight portion 9a of the torsion bar 9, in other words, in a plane that intersects (approximately orthogonal to) the longitudinal direction of the straight portion 9a.Specific embodiments (first and second embodiments) of such a fixed end position adjustment mechanism will be described below.

[0034] (First Embodiment) First, the fixed end position adjustment mechanism according to the first embodiment will be described with reference to Figures 7 to 9. Figure 7 is a top view of the fixed end position adjustment mechanism according to the first embodiment. In particular, Figure 7 is a partially enlarged view of the area around the fixed end 9c of the torsion bar 9. Figure 8 is a partial cross-sectional view taken along the line VIII-VIII in Figure 7, and Figure 9 is a perspective view of the contact plate 13 and the like with the torsion bar 9 removed.

[0035] As shown in Figure 7, the fixed end position adjustment mechanism 20a according to the first embodiment includes, in addition to the L-shaped contact plate 13 that holds the fixed end 9c of the torsion bar 9, a first bolt 14 for fixing the contact plate 13 to the fixed frame 12, a second bolt 15 whose tip abuts against the contact plate 13 to adjust the position of the contact plate 13 relative to the fixed frame 12, and a guide plate 16 that is fixed (welded) to the fixed frame 12 and extends in the direction of movement (front-rear direction) of the contact plate 13, with the contact plate 13 in contact with it.

[0036] The first bolt 14 is designed to fix the contact plate 13 to the fixing frame 12 by passing through holes 12a and 13a (Figure 9) formed in the fixing frame 12 and the contact plate 13, respectively. More specifically, the first bolt 14 passes through these through holes 12a and 13a and screws into a nut 17 (Figure 7) welded to the contact plate 13, thereby fixing the contact plate 13 to the fixing frame 12. Note that threads are not formed in the through holes 12a and 13a; in other words, the through holes 12a and 13a are not screw holes. In the example shown here, because the contact plate 13 is relatively thin, even if the through hole 13a of the contact plate 13 were formed as a screw hole, the contact plate 13 could not be securely fixed by the first bolt 14 using only the through hole 13a. Therefore, instead of making the through hole 13a a screw hole, a nut 17 is provided on the contact plate 13, and the contact plate 13 is fixed by the first bolt 14 using this nut 17. However, in other examples, if the contact plate 13 is made relatively thick, the through hole 13a of the contact plate 13 may be made as a screw hole without using the nut 17 described above, and the first bolt 14 may be screwed into this through hole 13a.

[0037] Next, as shown in Figure 7, the second bolt 15 passes through the fixed frame 12, and the tip of the second bolt 15 abuts against the surface of the contact plate 13 facing the fixed frame 12, thereby adjusting the position of the contact plate 13 relative to the fixed frame 12. The second bolt 15 is screwed into a through hole 12b (Figure 9) formed in the fixed frame 12, which is a threaded hole. When this second bolt 15 is rotated, the second bolt 15 moves relative to the fixed frame 12, or in other words, the amount by which the second bolt 15 protrudes from the fixed frame 12 changes, causing the contact plate 13 that contacts this second bolt 15 to move in the front-rear direction (arrow A31 in Figure 7). As a result, the fixed end 9c of the torsion bar 9 held by the contact plate 13 moves (rotates) in the front-rear direction (arrow A32 in Figure 7).

[0038] Specifically, when the second bolt 15 is tightened, it moves in a direction that protrudes from the fixed frame 12. In this case, the tip of the second bolt 15 pushes against the contact plate 13 (more specifically, it pushes against the torsional force (rebound force) acting forward on the torsion bar 9), causing the contact plate 13 to move backward, and the fixed end 9c also moves (rotates) backward. As a result, the amount of twist of the torsion bar 9 increases, and the torsional force increases. Conversely, when the second bolt 15 is loosened, it moves in a direction that retracts from the fixed frame 12. In this case, the contact plate 13 is pushed by the torsional force (rebound force) acting forward on the torsion bar 9, causing the contact plate 13 to move forward, and the fixed end 9c also moves (rotates) forward. As a result, the amount of twist of the torsion bar 9 decreases, and the torsional force decreases. In one example, moving the contact plate 13 and the fixed end 9c by about 2-3 cm using the second bolt 15 results in a change in torsional force corresponding to about 20-30 kg.

[0039] Here, the procedure for adjusting the torsional force of the torsion bar 9 using the fixed end position adjustment mechanism 20a will be described. First, the worker loosens the first bolt 14 that secures the contact plate 13 to the fixed frame 12. Typically, the worker removes the first bolt 14 from the fixed frame 12 and the contact plate 13. Then, the worker adjusts the position of the contact plate 13 by turning the second bolt 15. After the adjustment of the position of the contact plate 13 is complete, the worker inserts the first bolt 14 into the fixed frame 12 and the contact plate 13 and tightens the first bolt 14 to fix the position of the contact plate 13. For example, the worker can use a spanner, ratchet wrench, or box wrench to perform this adjustment work. In the first embodiment, the worker can access the fixed end position adjustment mechanism 20a from the right, front (arrows A41, A42 in Figure 7), up, and down (arrows A51, A52 in Figure 8) of the shovel 100 to perform the adjustment work. Furthermore, in order to enable adjustment work from the rear of the shovel 100 (arrow A43 in Figure 7), the first and second bolts 14 and 15 should be positioned so that their front-to-back orientations are opposite.

[0040] On the other hand, as shown in Figure 9, a projection 13b extending in the direction of movement (front-to-back direction) of the contact plate 13 is formed on the surface of the contact plate 13 that contacts the guide plate 16, and a slit 16a extending in the direction of movement (front-to-back direction) of the contact plate 13 is formed on the guide plate 16, which engages (fits) with the projection 13b of the contact plate 13. These projections 13b and slit 16a correspond to examples of the "engaging part" and "engaged part" in the present invention, respectively. The length of the slit 16a of the guide plate 16 is longer in the front-to-back direction than the length of the projection 13b of the contact plate 13 along the front-to-back direction, and is formed to a length corresponding to the range (amount of movement) of the contact plate 13. The contact plate 13 is moved with the projection 13b of the contact plate 13 engaged with the slit 16a of the guide plate 16 (Figure 8). This provides a trajectory for the contact plate 13 as it moves, prevents the contact plate 13 from falling off, and restricts the range of movement of the contact plate 13.

[0041] Next, the operation and effects of the first embodiment described above will be explained. In this embodiment, the shovel 100 has a main body 1 including at least a work implement 10 and a tilt floor 7 disposed on the main body 1, and the tilt floor 7 is configured to be able to tilt up and tilt down relative to the main body 1. The shovel 100 has a torsion bar 9 having a straight section 9a that generates a torsional force, a movable end 9b that extends from one end of the straight section 9a and contacts the lower surface of the tilt floor 7 and is rotatable to tilt the tilt floor 7 up by torsional force, and a fixed end 9c that extends from the other end of the straight section 9a and is fixed to a fixed frame 12 provided on the main body 1. The shovel 100 has a torsion bar 9 having a straight section 9a that generates a torsional force, a movable end 9b that extends from one end of the straight section 9a and is in contact with the lower surface of the tilt floor 7 and is rotatable to tilt the tilt floor 7 up by torsional force, and a fixed end position adjustment mechanism 20a configured to be able to adjust the position of the fixed end 9c of the torsion bar 9 in a direction intersecting the longitudinal direction of the straight section 9a of the torsion bar 9.

[0042] According to this embodiment, the torsional force of the torsion bar 9 can be appropriately adjusted by adjusting the position of the fixed end 9c of the torsion bar 9 using the fixed end position adjustment mechanism 20a. Specifically, the torsional force of the torsion bar 9 can be adjusted so that it is increased when the tilt floor 7 is tilted up, and so that it is decreased when the tilt floor 7 is tilted down. Therefore, according to this embodiment, it is possible to achieve both tilt-up and tilt-down operations of the tilt floor 7.

[0043] Furthermore, according to this embodiment, the straight section 9a of the torsion bar 9 extends in the left-right direction of the shovel 100, and the fixed end position adjustment mechanism 20a is configured to adjust the position of the fixed end 9c of the torsion bar 9 in the front-rear direction of the shovel 100, in a direction intersecting the longitudinal direction of the straight section 9a. As a result, by adjusting the front-rear position of the fixed end 9c, the amount of twist of the straight section 9a can be changed, and the torsional force provided by the torsion bar 9 can be precisely adjusted.

[0044] Furthermore, according to this embodiment, the fixed end position adjustment mechanism 20a has a contact plate 13 that contacts the fixed end 9c of the torsion bar 9 and adjusts the position of the fixed end 9c relative to the fixed frame 12. This makes it possible to adjust the position of the fixed end 9c relative to the fixed frame 12 by utilizing the contact plate 13 interposed between the fixed end 9c and the fixed frame 12.

[0045] Furthermore, according to this embodiment, the fixed end position adjustment mechanism 20a further includes a first bolt 14 for fixing the contact plate 13 to the fixed frame 12, and a second bolt 15 whose tip contacts the contact plate 13 to adjust the position of the contact plate 13 relative to the fixed frame 12. As a result, the position of the contact plate 13 relative to the fixed frame 12 can be appropriately adjusted by rotating the second bolt 15, and the contact plate 13 can be firmly fixed to the fixed frame 12 at the adjusted position by the first bolt 14.

[0046] Furthermore, according to this embodiment, the fixed end position adjustment mechanism 20a is further fixed to the fixed frame 12 and has a guide plate 16 that extends in the direction of movement (front-rear direction) of the contact plate 13 and into contact with the contact plate 13. The contact plate 13 has a projection 13b that extends in the front-rear direction, and the guide plate 16 has a slit 16a that extends in the front-rear direction and engages with the projection 13b. By moving the contact plate 13 with the projection 13b and the slit 16a engaged, the contact plate 13 can be moved along an appropriate trajectory, and the contact plate 13 can be prevented from falling off.

[0047] Furthermore, according to this embodiment, the slit 16a of the guide plate 16 is formed to receive the projection 13b of the contact plate 13, and the length of the slit 16a is longer than the length of the projection 13b and is formed to a length corresponding to the range of movement of the contact plate 13. This makes it possible to restrict the range of movement of the contact plate 13. Therefore, it is possible to prevent the amount of twist of the torsion bar 9 from becoming too large or too small, thereby preventing the torsional force from being set to be extremely strong or extremely weak.

[0048] Furthermore, according to this embodiment, the shovel 100 has a revo frame R provided on the main body 1, the movable end 9b of the torsion bar 9 is located near the inner wall surface of the revo frame R and on one end in the left-right direction, and the fixed end 9c of the torsion bar 9 is located near the inner wall surface of the revo frame R and on the other end in the left-right direction. This allows the straight portion 9a of the torsion bar 9 to be configured to be of sufficient length, and ensures that the magnitude of the torsional force provided by the torsion bar 9 is secured.

[0049] Furthermore, according to this embodiment, in the torsion bar 9, the movable end 9b and the fixed end 9c are formed by bending from one end and the other end of the straight section 9a, respectively. This generates a torsional force by twisting the straight section 9a at the fixed end 9c, and this torsional force can be used to accurately tilt up the tilt floor 7 by the movable end 9b.

[0050] (Second Embodiment) Next, the fixed end position adjustment mechanism according to the second embodiment will be described with reference to Figures 10 and 11. Note that the same configurations, operations, and effects as those of the first embodiment described above will be omitted from this description as appropriate. In other words, configurations, operations, and effects not specifically described here are assumed to be the same as those of the first embodiment.

[0051] Figure 10 is a top view of the fixed end position adjustment mechanism according to the second embodiment. In particular, Figure 10 is a partially enlarged view of the area around the fixed end 9c of the torsion bar 9. Figure 11 is a partially cross-sectional view taken along the line XI-XI in Figure 10.

[0052] As shown in Figure 10, the fixed end position adjustment mechanism 20b according to the second embodiment has a contact plate 13 and a guide plate 16, similar to the fixed end position adjustment mechanism 20a according to the first embodiment. However, the fixed end position adjustment mechanism 20b according to the second embodiment has a bolt 18 and first and second nuts 19a, 19b instead of the first bolt 14 and second bolt 15 of the fixed end position adjustment mechanism 20a according to the first embodiment. The bolt 18 penetrates the fixed frame 12 and the contact plate 13. For example, the bolt 18 penetrates through holes 12a, 13a (Figure 9) formed in the fixed frame 12 and the contact plate 13, respectively, as shown in the first embodiment. The first and second nuts 19a, 19b are screwed onto such a bolt 18 and sandwich the contact plate 13 from both sides.

[0053] Specifically, the first nut 19a abuts against the surface of the contact plate 13 that holds the fixed end 9c, thereby fixing the contact plate 13 to the fixing frame 12. More precisely, the first nut 19a, together with the second nut 19b, secures the contact plate 13 by sandwiching it from both sides.

[0054] Furthermore, the second nut 19b adjusts the position of the contact plate 13 relative to the fixed frame 12 by contacting the surface of the contact plate 13 facing the fixed frame 12. Specifically, when the first nut 19a is loosened, turning the second nut 19b causes the contact plate 13 that contacts the second nut 19b to move in the front-rear direction (arrow A61 in Figure 10). As a result, the fixed end 9c of the torsion bar 9 held by the contact plate 13 moves (rotates) in the front-rear direction (arrow A62 in Figure 10).

[0055] More specifically, when the second nut 19b is rotated so that it moves backward, the second nut 19b pushes against the contact plate 13 (more specifically, it pushes against the torsional force (repulsive force) acting forward on the torsion bar 9), causing the contact plate 13 to move backward and the fixed end 9c to also move (rotate) backward. As a result, the amount of twisting of the torsion bar 9 increases, and the torsional force increases. Conversely, when the second nut 19b is rotated so that it moves forward, the contact plate 13 is pushed by the torsional force (repulsive force) acting forward on the torsion bar 9, causing the contact plate 13 to move forward and the fixed end 9c to also move (rotate) forward. As a result, the amount of twisting of the torsion bar 9 decreases, and the torsional force decreases.

[0056] Here, the procedure for adjusting the torsional force of the torsion bar 9 using the fixed end position adjustment mechanism 20b will be described. First, the worker loosens the first nut 19a for fixing the contact plate 13 to the fixed frame 12. Then, the worker adjusts the position of the contact plate 13 by turning the second nut 19b. After the adjustment of the position of the contact plate 13 is complete, the worker fixes the position of the contact plate 13 by tightening the first nut 19a. For example, the worker can use a wrench or the like to perform this adjustment work. In the second embodiment, the worker can access the fixed end position adjustment mechanism 20b from the right side of the shovel 100 (arrow A71 in Figure 10), the upward direction, and the downward direction (arrows A81 and A82 in Figure 11) to perform the adjustment work.

[0057] Next, the operation and effects of the second embodiment described above will be explained. In this embodiment, the fixed end position adjustment mechanism 20b has a bolt 18 that passes through the fixed frame 12 and the contact plate 13, and first and second nuts 19a and 19b that are screwed onto the bolt 18 and sandwich the contact plate 13 from both sides. By using such a bolt 18 and first and second nuts 19a and 19b, the position of the contact plate 13 and the fixing of the contact plate 13 can be appropriately achieved.

[0058] Furthermore, in this embodiment, the first nut 19a can fix the contact plate 13 to the fixed frame 12, and the second nut 19b can adjust the position of the contact plate 13 relative to the fixed frame 12. As a result, by rotating the second nut 19b, the position of the contact plate 13 relative to the fixed frame 12 can be adjusted as appropriate, and the first nut 19a can firmly fix the contact plate 13 to the fixed frame 12 in the adjusted position.

[0059] In the embodiment described above, one first nut 19a was shown as the nut for fixing the contact plate 13 to the fixed frame 12, but two or more first nuts 19a may be used to fix the contact plate 13 to the fixed frame 12. Similarly, two or more second nuts 19b may be used to adjust the position of the contact plate 13 relative to the fixed frame 12.

[0060] [Differentiation] Next, a modified example of the above-described embodiment will be explained.

[0061] In the embodiment described above, a projection 13b was formed on the contact plate 13 and a slit 16a that engages with the projection 13b was formed on the guide plate 16. However, in other examples, a projection may be formed on the guide plate 16 and a slit that engages with this projection may be formed on the contact plate 13. Furthermore, in yet another example, instead of a through-slit, a recessed portion (recess) may be formed in the wall surface of the contact plate 13 or the guide plate 16.

[0062] Furthermore, in the above-described embodiment, a gas spring 8 was used in addition to the torsion bar 9 to assist in the tilt-up operation of the tilt floor 7, but in other examples, the gas spring 8 may not be used. In yet another example, a compression spring or a hydraulically operated hydraulic cylinder may be used instead of the gas spring 8.

[0063] Furthermore, in the embodiments described above, an example was shown in which the present invention is applied to an excavator 100 having a canopy 4 that mainly provides a roof 5 to protect the driver's seat. However, in other examples, the present invention may be applied to an excavator that is composed of a cab instead of a canopy 4. The cab is a room-like driver's seat equipped with a door, glass windows, etc., and, like the canopy 4, is configured to be tilted up and tilted down by rotating the tilt floor. In such other examples, it is preferable to provide a grip on the front of the cab. This allows the operator to apply force to the cab to tilt up and tilt down the tilt floor by grasping the grip and pushing or pulling it.

[0064] Furthermore, although the above-described embodiment shows an example of applying the present invention to a shovel 100, the present invention is not limited to application to a shovel 100, but can be applied to various work machines in which the tilt floor is configured to be able to tilt up and tilt down.

[0065] As described above, the embodiments and modifications described are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments and modifications. The present invention can be implemented in various forms without departing from its spirit.

[0066] (Note 1) A work machine comprising at least a main body including a work implement, and a tilt floor disposed on the main body, wherein the tilt floor is configured to be tiltable up and tiltable down relative to the main body, A torsion bar comprising: a straight section that generates a torsional force; a movable end extending from one end of the straight section and contacting the lower surface of the tilt floor, which is rotatable to tilt the tilt floor upward by the torsional force; and a fixed end extending from the other end of the straight section and fixed to a fixed frame provided on the main body; A fixed end position adjustment mechanism is configured to adjust the position of the fixed end of the torsion bar in a direction intersecting the longitudinal direction of the straight portion of the torsion bar, A work machine characterized by having (Note 2) The straight portion of the torsion bar extends in the left-right direction of the work machine, The fixed end position adjustment mechanism is configured to adjust the position of the fixed end of the torsion bar in the front-to-back direction of the work machine, which is a direction intersecting the longitudinal direction. The work machines described in Appendix 1. (Note 3) The working machine according to Appendix 1 or 2, wherein the fixed end position adjustment mechanism has a contact plate that contacts the fixed end of the torsion bar and adjusts the position of the fixed end relative to the fixed frame. (Note 4) The working machine as described in Appendix 3, wherein the fixed end position adjustment mechanism further comprises a first bolt for fixing the contact plate to the fixed frame, and a second bolt whose tip contacts the contact plate to adjust the position of the contact plate relative to the fixed frame. (Note 5) The working machine as described in Appendix 3, wherein the fixed end position adjustment mechanism further comprises a bolt that penetrates the fixed frame and the contact plate, and first and second nuts that are screwed with the bolt and sandwich the contact plate from both sides. (Note 6) The working machine according to Appendix 5, wherein the first nut can fix the contact plate to the fixed frame, and the second nut can adjust the position of the contact plate relative to the fixed frame. (Note 7) The fixed end position adjustment mechanism further has a guide plate that is fixed to the fixed frame and extends in the direction of movement of the contact plate, and into contact with the contact plate, An engaging portion extending in the direction of movement is formed on one of the guide plate and the contact plate, and an engaged portion extending in the direction of movement and engaging with the engaging portion is formed on the other of the guide plate and the contact plate. A work machine as described in any of the appendices 3 to 6. (Note 8) The working machine according to Appendix 7, wherein the engaged portion is formed to receive the engaging portion, and the length of the engaged portion along the direction of movement is longer than the length of the engaging portion along the direction of movement, and is formed to a length corresponding to the range over which the contact plate is moved. (Note 9) The aforementioned work machine has an outer wall frame provided on the main body, The movable end of the torsion bar is located near the inner wall surface of the outer wall frame and on one end side in a predetermined direction of the work machine, and the fixed end of the torsion bar is located near the inner wall surface of the outer wall frame and on the other end side in the predetermined direction. A work machine as described in any of the appendices 1 to 8. (Note 10) The working machine according to any one of the appendices 1 to 9, wherein the movable end and the fixed end of the torsion bar are formed by bending from one end and the other end of the straight section, respectively. (Note 11) A work machine comprising at least a main body including a work implement, and a tilt floor disposed on the main body, wherein the tilt floor is configured to be tiltable up and tiltable down relative to the main body, A torsion bar comprising: a straight section that generates a torsional force; a movable end formed by bending from one end of the straight section and contacting the lower surface of the tilt floor, allowing it to rotate so as to tilt the tilt floor upward by the torsional force; and a fixed end formed by bending from the other end of the straight section and fixed to a fixed frame provided on the main body; A fixed end position adjustment mechanism is configured to adjust the position of the fixed end of the torsion bar so as to change the magnitude of the torsional force generated by the straight portion of the torsion bar, A work machine characterized by having [Explanation of symbols]

[0067] 1…Main body, 2…Lower running body, 3…Upper rotating body, 4…Canopy, 7…Tilt floor, 9…Torsion bar, 9a…Straight section, 9b…Movable end, 9c…Fixed end, 10…Work implement, 12…Fixed frame, 13…Contact plate, 13b…Protrusion, 14…First bolt, 15…Second bolt, 16…Guide plate, 16a…Slit, 18…Bolt, 19a…First nut, 19b…Second nut, 20a, 20b…Fixed end position adjustment mechanism, R…Revo frame (outer wall frame)

Claims

1. A work machine comprising at least a main body including a work implement, and a tilt floor disposed on the main body, wherein the tilt floor is configured to be tiltable up and tiltable down relative to the main body, A torsion bar comprising: a straight section that generates a torsional force; a movable end extending from one end of the straight section and contacting the lower surface of the tilt floor, which is rotatable to tilt the tilt floor upward by the torsional force; and a fixed end extending from the other end of the straight section and fixed to a fixed frame provided on the main body; A fixed end position adjustment mechanism is configured to adjust the position of the fixed end of the torsion bar in a direction intersecting the longitudinal direction of the straight portion of the torsion bar, A work machine characterized by having

2. The straight portion of the torsion bar extends in the left-right direction of the work machine, The fixed end position adjustment mechanism is configured to adjust the position of the fixed end of the torsion bar in the front-to-back direction of the work machine, which is a direction intersecting the longitudinal direction. The work machine according to claim 1.

3. The working machine according to claim 1, wherein the fixed end position adjustment mechanism has a contact plate that contacts the fixed end of the torsion bar and adjusts the position of the fixed end relative to the fixed frame.

4. The working machine according to claim 3, wherein the fixed end position adjustment mechanism further comprises a first bolt for fixing the contact plate to the fixed frame, and a second bolt whose tip contacts the contact plate to adjust the position of the contact plate with respect to the fixed frame.

5. The working machine according to claim 3, wherein the fixed end position adjustment mechanism further comprises a bolt that penetrates the fixed frame and the contact plate, and first and second nuts that are screwed with the bolt and sandwich the contact plate from both sides.

6. The working machine according to claim 5, wherein the first nut is capable of fixing the contact plate to the fixed frame, and the second nut is capable of adjusting the position of the contact plate with respect to the fixed frame.

7. The fixed end position adjustment mechanism further has a guide plate that is fixed to the fixed frame and extends in the direction of movement of the contact plate, and into contact with the contact plate, An engaging portion extending in the direction of movement is formed on one of the guide plate and the contact plate, and an engaged portion extending in the direction of movement and engaging with the engaging portion is formed on the other of the guide plate and the contact plate. The work machine according to claim 3.

8. The working machine according to claim 7, wherein the engaged portion is formed to receive the engaging portion, and the length of the engaged portion along the direction of movement is longer than the length of the engaging portion along the direction of movement, and is formed to a length corresponding to the range over which the contact plate is moved.

9. The aforementioned work machine has an outer wall frame provided on the main body, The movable end of the torsion bar is located near the inner wall surface of the outer wall frame and on one end side in a predetermined direction of the work machine, and the fixed end of the torsion bar is located near the inner wall surface of the outer wall frame and on the other end side in the predetermined direction. The work machine according to claim 1.

10. The work machine according to claim 1, wherein the movable end and the fixed end of the torsion bar are formed by bending from one end and the other end of the straight section, respectively.

11. A work machine comprising at least a main body including a work implement, and a tilt floor disposed on the main body, wherein the tilt floor is configured to be tiltable up and tiltable down relative to the main body, A torsion bar comprising: a straight section that generates a torsional force; a movable end extending from one end of the straight section and contacting the lower surface of the tilt floor, which is rotatable to tilt the tilt floor upward by the torsional force; and a fixed end extending from the other end of the straight section and fixed to a fixed frame provided on the main body; A fixed end position adjustment mechanism is configured to adjust the position of the fixed end of the torsion bar so as to change the magnitude of the torsional force generated by the straight portion of the torsion bar, A work machine characterized by having

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