Construction machine

Abstract

To provide a hydraulic shovel characterized in that blocking a drop of a cab or canceling the blocking can be achieved with a simple maneuver without a necessity of attaching or detaching work.SOLUTION: A hydraulic shovel 1 includes a lower traveling body 2, a cab 5 located on an upper turning body 3, a cab raise / drop drive cylinder 7 that raises or drops the cab 5, a link mechanism 6 that keeps the cab 5, which is raised or dropped by the cab raise / drop drive cylinder 7, in a predetermined posture, a support tower 8 that supports the link mechanism 6, and a drop restriction mechanism 16 that restricts the drop of the cab 5 at a predetermined drop restriction position. The drop restriction mechanism 16 can move rotationally with respect to the support tower 8 and move in a direction of approaching or receding from the link mechanism 6 in a direction perpendicular to the rotational movement direction, and includes a rotation maneuver member 120 capable of rotating between a first angular position at which the drop restriction mechanism moves toward the link mechanism 6 so as to block the drop of the cab 5 and a second angular position at which the drop restriction mechanism recedes from the link mechanism 6 so as to cancel the blocking of the drop of the cab 5.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a construction machine having a cab that can be raised and lowered. [Background technology]

[0002] Patent Document 1 discloses a work machine having a link mechanism for raising and lowering a cab, a support tower body that supports the link mechanism, and a descent restriction mechanism that restricts the descent of the cab at a predetermined descent restriction position, wherein the descent restriction mechanism has a receiving portion provided at a position corresponding to the descent restriction position of the support tower body, and an engaging member provided on the link mechanism so as to be movable between an engagement position that engages with the receiving portion and a non-engagement position that is spaced apart from the receiving portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-101870 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the technology of Patent Document 1, when preventing and locking the driver's cab from descending, the engaging member must be moved to the mounting position and fixed to the support tower body with a fastening member, and when releasing the lock, the engaging member must be removed from the support tower body, which makes these operations cumbersome.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide a construction machine in which the prevention of descent of the operator's cab and the release of this prevention can be performed with a simple operation, without the need for installation and removal work. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a construction machine having a vehicle body, a driver's cab provided on the vehicle body, a lifting drive unit that raises and lowers the driver's cab, a link mechanism that maintains the driver's cab raised and lowered by the lifting drive unit in a predetermined position, a support body that supports the link mechanism, and a descent restriction mechanism that restricts the descent of the driver's cab at a predetermined descent restriction position, wherein the descent restriction mechanism is rotatable relative to the support body and movable toward and away from the link mechanism along a direction perpendicular to the rotation direction, and is provided with a rotary operating member that can rotate between a first angular position where it moves toward the link mechanism to prevent the descent of the driver's cab, and a second angular position where it moves away from the link mechanism to release the prevention of the descent of the driver's cab. [Effects of the Invention]

[0007] According to the present invention, the prevention of descent of the operator's cab and the release of this prevention can be performed by a simple operation without the need for installation and removal work. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the structure of a hydraulic excavator according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged perspective view showing a detailed structure in the vicinity of a descent restriction mechanism, which is a main part in FIG. 1. [Figure 3] FIG. 3 is a perspective view showing the overall structure of the rotation operation member shown in FIGS. 1 and 2. [Figure 4] FIG. 2 is a perspective view of the hydraulic excavator in a lowering prevention state. [Figure 5] FIG. 10 is a left side view showing a detailed structure in the vicinity of the rotation operating member in a lowering prevention release state. [Figure 6] 10 is a cross-sectional view showing a detailed structure of the vicinity of the rotation operating member in a descent prevention release state. FIG. [Figure 7] FIG. 10 is an enlarged perspective view showing a detailed structure in the vicinity of the descent restriction mechanism in a descent-blocking state. [Figure 8] FIG. 10 is a left side view showing a detailed structure in the vicinity of the rotation operating member in a lowering prevention state. [Figure 9] 10 is a cross-sectional view showing a detailed structure in the vicinity of the rotation operation member in a downward blocking state. FIG. [Figure 10] FIG. 10 is an enlarged perspective view showing a state in which the rotation operation member is in the middle of rotation. [Figure 11] FIG. 10 is a cross-sectional view showing a state in which the rotation operation member is in the middle of rotation. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] <Overview of hydraulic excavators> Fig. 1 shows a hydraulic excavator 1, which is an example of a construction machine according to this embodiment. In the following description, the up-down direction, the front-rear direction, and the left-right direction correspond to the directions of arrows shown appropriately in each drawing such as Fig. 1. In other words, "up," "down," "front," "rear," "left," and "right" shown in the drawing correspond to the up-down, left-right, front-rear directions as seen from an operator seated in a cab 5 (described below).

[0011] The hydraulic excavator 1 has a vehicle body consisting of a self-propelled crawler-type lower running body 2 and an upper rotating body 3 rotatably mounted on the lower running body 2, and a working device 56 attached to the upper rotating body 3 so that it can be raised and lowered.

[0012] The working device 56 is configured as an articulated type that includes a boom 67 that is provided so as to be able to move up and down, and an arm 68 that is rotatably connected to the boom 67. A predetermined attachment 69 is rotatably connected to the tip of the arm 68. The boom 67, arm 68, and attachment 69 are operated by a boom hydraulic cylinder 70, an arm hydraulic cylinder 71, and an attachment hydraulic cylinder 72, which serve as hydraulic actuators, respectively.

[0013] A cab lifting device 4 is provided on the left side of the upper revolving body 3, and this cab lifting device 4 can be used to raise and lower a cab 5 (operator's compartment).

[0014] <Cab lifting device> The cab lifting / lowering device 4 raises and lowers the cab 5 while maintaining the horizontal position (predetermined position) of the cab 5. The cab lifting / lowering device 4 has a link mechanism 6, a support tower body 8 (support body) that supports the link mechanism 6, and a cab lifting / lowering drive cylinder 7 (lifting / lowering drive unit).

[0015] The link mechanism 6 has a base 9, an upper link 10, and a lower link 11. The base 9 is provided below the cab 5 and supports the cab 5 from below. The support towers 8 are erected on the upper rotating body 3 and are provided on the left and right sides of the upper link 10 and the lower link 11. The upper link 10 and the lower link 11 are rotatably connected at their respective ends by pins 12 and 13 on one end and pins 14 and 15 on the other end. Although not shown in FIG. 1, the upper link 10 and the lower link 11 are arranged in pairs on the left and right in the width direction of the cab, similar to the support towers 8.

[0016] The cab lifting drive cylinder 7 has a rod whose tip end is axially supported by the upper revolving body 3 and whose lower end is connected to a connecting member (not shown) disposed on a pair of lower links 11 .

[0017] The cab lifting device 4 drives the link mechanism 6 by extending and retracting the cab lifting drive cylinder 7, thereby raising and lowering the cab 5. Specifically, as the cab lifting drive cylinder 7 extends and retracts, the upper link 10 and the lower link 11 that constitute the link mechanism 6 rotate about pins 12 and 13. As a result, the cab 5 rises and falls while maintaining a horizontal position.

[0018] <Descent regulation mechanism> When maintenance work is performed on the hydraulic excavator 1, maintenance of the cab lifting device 4 is also performed. At that time, it is difficult to perform maintenance with the cab 5 in a lowered state. Therefore, maintenance work on the cab lifting device 4 must be performed with the cab 5 raised to a predetermined position. However, during the maintenance work, there is a possibility that a worker may get under the cab 5, and in order to ensure the safety of the worker, it is necessary to restrict the descent of the cab 5. For this reason, the hydraulic excavator 1 of this embodiment is provided with a descent restriction mechanism 16, as shown in FIG. 2.

[0019] 1 , the above-described support tower 8, upper link 10, and lower link 11 are provided on both the left and right sides of the attitude of the upper rotating body 3, and accordingly, a descent restriction mechanism 16, the details of which will be described below, is also provided on both the left and right sides. That is, two descent restriction mechanisms are provided: a left descent restriction mechanism 16 provided on the left support tower 8 and controlling the descent of the cab 5 via the left upper link 10 and lower link 11, and a right descent restriction mechanism 16 provided on the right support tower 8 and controlling the descent of the cab 5 via the right upper link 10 and lower link 11. The left descent restriction mechanism 16 and the right descent restriction mechanism 16 are essentially identical in configuration, except for the difference in whether they are located on the left or right side (the mutual positional relationship of each component is the same when viewed from the link mechanism 6 side and the opposite side to the link mechanism 6 side). Therefore, hereinafter, unless otherwise specified, they will not be distinguished from each other and will be simply referred to as the "descent restriction mechanism 16."

[0020] In FIG. 2, the downward movement restriction mechanism 16 of this embodiment has a rotation operation member 120 that penetrates the support tower body 8.

[0021] <Rotation operation member> As shown in FIG. 3 , the rotation operation member 120 includes a plate-shaped plate member 121 (contact portion), a grip portion 122, and a pin portion 123. The pin portion 123 is inserted into a through-hole 8A (see FIG. 6 , etc., described later) of the support tower 8, thereby allowing the rotation operation member 120 to rotate with respect to the support tower 8. The rotation operation member 120 is configured so that an operator can manually grasp the grip portion 122 and rotate it clockwise and counterclockwise. The rotation operation member 120 is also configured so that the depth of insertion into the through-hole 8A of the support tower 8 can be adjusted. That is, the rotation operation member 120 is attached to the support tower 8 so as to rotate about the through-hole 8A provided in the support tower 8 as a rotation axis (center of rotation), and to move toward and away from the link mechanism 6 along the axial direction (direction perpendicular to the direction of rotation) of the rotation axis (central axis of the rotation center).

[0022] <Preventing the driver's cab from descending> For example, when the grip portion 122 is rotated and the entire rotation operation member 120 approaches the link mechanism 6, the pin portion 123 projects from the support tower 8 toward the link mechanism 6 (more specifically, to a state where it can abut against the lower link 11) (a descent-restricted position; see Figures 8 and 9 described below). In this state, the pin portion 123 enters the range of motion of the link mechanism 6. Therefore, the cab 5 gradually descends from the state shown in Figure 1, and the lower link 11 abuts against the pin portion 123, thereby preventing further descent of the cab 5. Figure 4 shows the descent-restricted mechanism 16 in the hydraulic excavator 1 in the descent-blocked state where the pin portion 123 abuts against the lower link 11 as described above.

[0023] <Removing the descent prevention of the driver's cab> From the above-mentioned descent restriction position, for example, by rotating the grip portion 122 in the opposite direction to the above and moving the rotation operation member 120 as a whole in a direction away from the link mechanism 6 (more specifically, the link opposite to the lower link 11), the pin portion 123 is accommodated in the support tower 8 and no longer protrudes from the support tower 8 (descent restriction release position; see FIG. 2 above and FIGS. 5 and 6 below). In this state, the pin portion 123 is located at a position outside the range of motion of the link mechanism 6. Therefore, the lower link 11 no longer interferes with the pin portion 123, and the above-mentioned descent restriction of the cab 5 is released. FIG. 1 above shows the state in the hydraulic excavator 1 in which the descent restriction mechanism 16 is in the descent restriction release state in which the pin portion 123 and the lower link 11 do not interfere with each other as described above.

[0024] A specific structure for realizing the above-described operational behavior of the descent restriction mechanism 16 will be described below in order.

[0025] <Details of the rotation operation part> As shown in Fig. 5, the plate member 121 of the rotation operation member 120 has a generally spindle-shaped (or may have a diamond-shaped or generally elliptical) shape in which the longitudinal dimension L1 in a plan view is greater than the lateral dimension L2. Also, as shown in Fig. 3 above, an elongated engagement hole 125 is provided on one side in the longitudinal direction (the lower left side in Fig. 5) of the rotation center k of the plate member 121. Furthermore, an engagement claw 124 that is engaged by the engagement member 21 is provided on another side in the longitudinal direction (the lower left side in Fig. 5) of the engagement hole 125. The lateral direction of the plate member 121 generally coincides with the long axis direction of the engagement hole 125.

[0026] 3, a stepped portion 126 with a mounting surface 127 is formed at the tip of the pin portion 123 of the rotation operation member 120 on the link mechanism 6 side (more specifically, on the lower link 11 side). This mounting surface 127 is formed on the stepped portion 126 so as to be approximately horizontal when the rotation operation member 120 is at the angle (first angle position) shown in FIGS. 7, 8, and 9 described later (see FIG. 9 described later). The surface direction of this mounting surface 127 is approximately parallel to the minor axis direction of the engagement hole 125 (see FIG. 3).

[0027] As shown in FIGS. 2, 5 and 6, the descent restriction mechanism 16 has, in addition to the rotation operation member 120, support columns 17, 18 and 19 respectively provided on the support tower 8, and an engagement member .

[0028] <Retention and engagement of plate member in descent prevention release state> The support column 17 is provided above the through-hole 8A in the support tower 8, and has a substantially cylindrical shape. The support column 19 is provided below the through-hole 8A in the support tower 8. The support column 19 is composed of a substantially cylindrical support column body 19E, a spacer 19C formed integrally with the tip of the support column body 19E and having a smaller diameter than the support column body 19E, a washer 19B attached to the end of the spacer 19C on the side of the support column body 19D to prevent protrusion, and a washer 19D fixed to the tip of the spacer 19C (the end opposite the support column body 19D) with a bolt 19A to prevent separation. As shown in FIG. 6 and other figures, the combined dimension of the height (length in the left-right direction) of the support column body 19E and the thickness of the washer 19B in the support column 19 is substantially equal to the height (length in the left-right direction) of the support column 17.

[0029] When the rotation angle of the rotation operation member 120 is the angle (second angle position) that realizes the descent prevention release state shown in Figure 1 etc., the longitudinal direction of the rotation operation member 120 is approximately vertical in this example, as shown in Figures 2, 5, and 6. In this state, as shown in Figures 2 and 5, the pin portion 123 described above is retracted toward the side opposite the link mechanism 6 from the support tower 8, in other words, the plate member 121 is separated from the surface of the support tower 8 on the side opposite the link mechanism 6 and floats up.

[0030] In the state where the plate members 121 are spaced apart as described above, the support pillars 17 come into contact with the rear surface of the plate members 121 on the support tower body 8 side, thereby maintaining the plate members 121 in the spaced apart state. Furthermore, at this time, the support column 19 is engaged with the engagement hole 125 of the plate member 121. More specifically, in the engagement hole 125, the washer 19B engaged with the end of the support column main body 19E on the side opposite to the link mechanism 6 abuts against the back surface of the plate member 121 on the side opposite to the link mechanism 6, and the washer 19D engaged with the end of the spacer 19C on the side opposite to the link mechanism 6 by the bolt 19A abuts against the surface of the plate member 121 on the side opposite to the link mechanism 6. As a result, the spacer 19C located between the washers 19B and 19D is hooked and engaged with the engagement hole 125. As a result, the support column 19 also maintains the separation state of the plate member 121 from the support tower body 8 described above. In other words, the support column 19 and the support column 17 described above function as separation maintaining members. Furthermore, because the support portion 19 functions to limit the rotation of the rotation operation member 120 through the engagement described above, there is no need for a separate fastening member or the like to fix the plate member 121 so that it does not move.

[0031] As shown in Fig. 3, the engagement hole 125 of the plate member 121 has a generally spindle-shaped (or diamond-shaped or generally elliptical) shape in a plan view, with a longitudinal dimension L3 greater than a lateral dimension L4 (see Fig. 10, described later). The lateral dimension L4 decreases toward the longitudinal end of the engagement hole 125. In other words, the opening size (hole diameter) of the engagement hole 125 decreases from the center of the engagement hole 125 toward the longitudinal direction.

[0032] At this time, the outer diameter of the washer 19D in the support portion 19 is smaller than the opening size at the center of the engagement hole 125, but is smaller than the opening size at the longitudinal end of the engagement hole 125. Therefore, as shown in Figures 2, 5 and 6, by setting the rotation angle of the rotation operation member 120 so that the support portion 19 is positioned at the longitudinal end of the engagement hole 125, the washer 19D performs a retaining function that prevents the plate member 121 from slipping out to the side opposite the link mechanism 6. On the other hand, by adjusting the rotation angle of the rotary operating member 120 so that the support portion 19 is positioned in the center of the engagement hole 125 (not shown), the operator can grasp the gripping portion 122 and pull the plate member 121 toward the side opposite the link mechanism 6, thereby disengaging the support portion 19 from the engagement hole 125.

[0033] At this time, the engaging member 21 (holding member) is disposed below the support column 19 of the support tower 8. This engaging member 21 engages with the locked claw 124 located near the bottom of the plate member 121 when the rotation angle of the rotation operating member 120 is the angle (second angle position) shown in Figures 2, 5, and 6. This fixes the rotation operating member 120 to prohibit rotation, and also prevents the rotation operating member 120 from coming off the support columns 17, 19 due to vibrations while the hydraulic excavator 1 is in operation.

[0034] In this descent prevention release state, the support column 17 also serves to prevent the rotation operation member 120 from rotating to an angle (first angle position) that realizes a descent prevention state described below by coming into contact with the plate member 121. Furthermore, the support column 17 also serves to prevent the surface of the plate member 121 from being held in a state in which it is inclined obliquely and not parallel to the surface of the support tower body 8 on the side opposite to the link mechanism 6.

[0035] <Engagement of Plate Members in the Descending Prevention State> On the other hand, the support pillar 18 (engagement protrusion) is provided in front of the through-hole 8A in the support tower 8, and has a substantially cylindrical shape. As shown in Fig. 6 and other figures, the height (length in the left-right direction) of the support pillar 18 is smaller than those of the support pillars 17 and 19, and is spaced apart from the back surface of the rotation operation member 120 (the surface on the link mechanism 6 side) when the rotation operation member 120 is in the second angular position shown in Fig. 5 and other figures.

[0036] The support column 18 is made up of a substantially cylindrical support column body 18C and a washer 18B for preventing separation, which is fixed to the tip end (the end opposite the support column body 18C) of the support column body 18C with a bolt 18A. As shown in Fig. 6 etc., the height (length in the left-right direction) of the support column body 18C in the support column 18 is substantially equal to the thickness of the plate member 121.

[0037] When the rotation angle of the rotation operation member 120 is the angle (first angle position) that realizes the descent prevention state shown in Fig. 4 etc., the longitudinal direction of the rotation operation member 120 is approximately horizontal in this example, as shown in Fig. 7, Fig. 8, and Fig. 9. In this state, as shown in Fig. 7 and Fig. 9, the pin portion 123 is pressed toward the link mechanism 6 side relative to the support tower body 8, in other words, the plate member 121 is in contact with the surface of the support tower body 8 on the side opposite to the link mechanism 6.

[0038] When the plate member 121 is in contact as described above, the support portion 18 is engaged with the engagement hole 125 of the plate member 121. More specifically, in the engagement hole 125, the washer 18B, which is locked by the bolt 18A to the end of the support main body 18C on the side opposite to the link mechanism 6, is in contact with the surface of the plate member 121 on the side opposite to the link mechanism 6. As a result, the portion of the support main body 18C that is positioned closer to the link mechanism 6 than the washer 18B is hooked and engaged with the engagement hole 125. As a result, the support portion 18 fulfills the function of limiting the rotation of the rotation operation member 120 through the engagement, and therefore no additional fastening member or the like is required to fix the plate member 121 so as not to move.

[0039] As described above, the opening size (hole diameter) of the engagement hole 125 of the plate member 121 becomes smaller from the center of the engagement hole 125 toward the longitudinal direction. The outer diameter of the washer 18B in the support portion 18 is smaller than the opening size of the engagement hole 125 at the center, but smaller than the opening size of the engagement hole 125 at the longitudinal end portion. Therefore, as shown in Figures 7, 8, and 9, by setting the rotation angle of the rotation operation member 120 so that the support portion 18 is positioned at the longitudinal end portion of the engagement hole 125, the washer 18B performs a retaining function that prevents the plate member 121 from slipping out toward the side opposite the link mechanism 6. On the other hand, by adjusting the rotation angle of the rotary operating member 120 so that the support portion 18 is positioned in the center of the engagement hole 125 (not shown), the operator can grasp the gripping portion 122 and pull the plate member 121 toward the side opposite the link mechanism 6, thereby disengaging the support portion 18 from the engagement hole 125.

[0040] As already mentioned, a mounting surface 127 is provided on the stepped portion 126 located at the tip of the pin portion 123 of the rotation operating member 120 on the link mechanism 6 side (more specifically, on the lower link 11 side). The mounting surface 127 is in a substantially horizontal direction when the rotation operating member 120 is at the angle (first angle position) shown in FIGS. 7, 8, and 9. As shown in FIG. 9, this mounting surface 127 abuts against the lower link 11 from below on the link mechanism 6 side of the support tower 8 (the lower link 11 is mounted on it), thereby preventing the lower link 11 and the cab 5 from descending below the position of the rotation operating member 120.

[0041] <Summary of rotation operation of the rotation operation part> In the above configuration, the flow when the operator rotates the rotary operation member 120 to switch between the above-mentioned lowering restriction position and the lowering restriction release position will be summarized below.

[0042] <Descent restriction position→Descent restriction release position> 7, 8, and 9 (an example of the first angular position), hold the grip portion 122 of the rotation operation member 120, and rotate it a small angle in a predetermined rotation direction (clockwise in the example of FIGS. 7 to 9) until the support portion 19 located at the longitudinal end of the engagement hole 125 is positioned in the center of the engagement hole 125. This releases the engagement between the washer 18B and the engagement hole 125.

[0043] Then, the entire rotation operating member 120 is pulled to the right using the gripping portion 122 so that the plate member 121 is further to the right (i.e., the side opposite the link mechanism 6; the same applies below) by the thickness of the spacer 19C from the left-right position shown in Figure 6.

[0044] Thereafter, the entire rotation operation member 120 is rotated approximately 90° in an appropriate direction (counterclockwise in the examples of FIGS. 7 and 8) using the grip portion 122, so that the bolt 19A and washer 19D of the support portion 19 face the engagement hole 125 of the plate member 121 (a position rotated slightly clockwise from the position shown in FIGS. 2 and 5). The angular position of the rotation operation member 120 at this time is an example of the second angular position described above. Also, FIGS. 10 and 11 show a state midway through the approximately 90° rotation.

[0045] Then, using the grip portion 122, the entire rotation operating member 120 is pushed to the left (i.e., toward the link mechanism 6; the same applies below) to insert the bolt 19A and washer 19D of the support portion 19 into the engagement hole 125 of the plate member 121, while abutting the back surface of the plate member 121 against the support portion 17.

[0046] Thereafter, the grip portion 122 of the rotation operation member 120 in the above angular position is held, and rotated a small angle in a predetermined rotation direction (counterclockwise in the examples of FIGS. 2 and 5) until the support portion 19 located in the center of the engagement hole 125 is positioned at the longitudinal end of the engagement hole 125. This causes the washers 19B and 19D to engage with the engagement hole 125, as shown in FIGS. 2, 5, and 6.

[0047] <Descent restriction release position→Descent restriction position> The above steps can be reversed, so the explanation will be omitted.

[0048] <Effects of the embodiment> As described above, in this embodiment, the cab 5 is raised and lowered by the cab lifting drive cylinder 7, and is configured to maintain the cab 5 in a horizontal position by the link mechanism 6 during raising and lowering. At that time, the lowering of the cab 5 is restricted at the above-mentioned lowering restricted position by the lowering restricting mechanism 16. For this purpose, the lowering restricting mechanism 16 is provided with a rotation operating member 120 that is rotatable between a first angular position and a second angular position.

[0049] The operator rotates the rotation operation member 120 to a first angular position (see FIGS. 7 to 9) and pushes the rotation operation member 120 to move it toward the link mechanism 6 (to the left in the examples shown in FIGS. 7 to 9), thereby preventing and locking the cab 5 from lowering. The operator rotates the rotation operation member 120 to a second angular position (see FIGS. 2 to 6) and pulls the rotation operation member 120 to move it to the opposite side, away from the link mechanism 6 (to the right in the examples shown in FIGS. 2 to 6), thereby releasing the prevention of the cab 5 from lowering.

[0050] As described above, in this embodiment, the operator can prevent or release the descent of the cab 5 by simply performing the simple operation of rotating the rotation operating member 120 that is pre-installed on the support tower body 8, without having to perform work such as attaching or detaching a separate member. Furthermore, this embodiment is configured to operate the rotation operation member 120, which does not separate from the support tower 8 as described above. Therefore, there is no risk of the operator having to perform heavy operations, as in the case where the support tower side and the movable side are aligned and a pin is inserted to prevent descent. Furthermore, there is no risk of losing the member used to execute the lock, as in the case where a separate member is attached and detached to prevent descent.

[0051] Furthermore, particularly in this embodiment, in the rotation operating member 120, the pin portion 123 that penetrates the support tower body 8 and the plate member 121 provided on the side of the support tower body 8 opposite the link mechanism 6 are integrally constructed. When the operator rotates the rotation operating member 120 to the first angle position and moves it toward the link mechanism 6, the plate member 121 comes into contact with the surface of the support tower 8 on the side opposite to the link mechanism 6, and the pin portion 123 protrudes from the support tower 8 toward the link mechanism 6. This protrusion of the pin portion 123 toward the link mechanism 6 prevents the cab 5 from descending and locks it (see Figure 9, etc.). On the other hand, when the operator rotates the rotation operating member 120 to the second angle position and moves it away from the link mechanism 6, the plate member 121 moves away from the surface of the support tower body 8 on the side opposite to the link mechanism 6, and the pin portion 123 no longer protrudes toward the link mechanism 6 (see FIG. 6, etc.). This allows the cab 5 to be released from the state where it is prevented from descending.

[0052] When the rotation operating member 120 is in the second angular position and the prevention of descent of the cab 5 is released, as described above, the plate member 121 is spaced apart from the surface of the support tower body 8 on the side opposite to the link mechanism 6. In this embodiment, in particular, the support pillars 17, 19 maintain this spaced apart state (see FIG. 6, etc.), so that the release state of the prevention of descent of the cab 5 in the second angular position can be stably maintained.

[0053] Furthermore, in this embodiment in particular, when the rotation operating member 120 is in the second angular position and the prevention of descent of the cab 5 is released, the engaging member 21 engages with the plate member 121 (see Figures 2, 5, etc.). This makes it possible to stably maintain the release state of the prevention of descent of the cab 5 in the second angular position.

[0054] Furthermore, particularly in this embodiment, when the rotation operating member 120 is in the first angular position and the cab 5 is in the descent-prevented state, the plate member 121 abuts against the surface of the support tower 8 on the side opposite to the link mechanism 6, as described above (see FIG. 9). At this time, in this embodiment, the support column 18 provided on the support tower 8 engages with the engagement hole 125 provided in the plate member 121 (see FIGS. 7 and 8). This maintains the abutment state, and the descent-prevented state of the cab 5 in the first angular position can be stably maintained.

[0055] Furthermore, particularly in this embodiment, when the substantially spindle-shaped or substantially elliptical plate member 121 is oriented horizontally (with its longitudinal direction oriented substantially horizontally) at the first angular position, the long axis direction of the engagement hole 125 is oriented substantially vertically. As a result, as shown in FIG. 7 and other figures, the vertically oriented engagement hole 125 is located on one side (the front side in the illustrated example) of the rotation center of the rotation operating member 120 in the horizontally oriented plate member 121, and the support column 18 of the support tower 8 engages with the vertically oriented engagement hole 125. In this case, even when the operator releases his / her hand from the grip portion 122 and assumes a natural position, the support column 18 is pressed against one end (upper end) of the vertically oriented engagement hole 125 due to slight rotation (tilt) caused by the weight of the plate member 121 (see FIGS. 7 and 8 ). Therefore, the engagement state between the support column 18 and the engagement hole 125 is reliably maintained. As a result, the cab 5 can be stably prevented from descending at the first angular position.

[0056] Furthermore, particularly in this embodiment, when the rotation operating member 120 is in the first angular position and the cab 5 is in a state where it is prevented from lowering, the support surface 127 provided on the stepped portion 126 of the pin portion 123 is in a substantially horizontal direction (see FIG. 9). As a result, the support surface 127 extending in the horizontal direction abuts from below against the link mechanism 6 (more specifically, the lower link 11), which operates as the cab 5 lowers (in other words, the abutment surface of the link mechanism 6 is placed on the support surface 127), and after the abutment, further lowering of the cab 5 can be prevented. Because the descent is prevented by the abutment of the link mechanism 6 with a substantially horizontal surface, the cab 5 can be kept in a state where it is prevented from lowering with high reliability.

[0057] Furthermore, particularly in this embodiment, as described above, when the rotation operating member 120 is in the first angular position to prevent the cab 5 from lowering, the surface direction of the mounting surface 127 of the pin portion 123, which is in the substantially horizontal direction, is substantially parallel to the minor axis direction of the engagement hole 125 (see FIG. 3). That is, in the first angular position, the engagement hole 125 is disposed vertically with its major axis direction being substantially vertical, and the substantially spindle-shaped or substantially elliptical plate member 121 is disposed horizontally with its longitudinal direction being substantially horizontal (see FIGS. 7, 8, etc.). The horizontally oriented plate member 121 is provided with a vertically oriented engagement hole 125 on one side (the front side in the illustrated example) from the rotation center, and the support column portion 18 of the support tower body 8 is configured to engage with the vertically oriented engagement hole 125. In this case, even when the operator releases the grip portion 122 and assumes a natural position, the slight rotation (tilt) of the plate member 121 due to its own weight presses the support portion 18 against one end (upper end) of the vertically oriented engagement hole 125 (see FIGS. 7 and 8), and the engagement state between the support portion 18 and the engagement hole 125 is stably maintained. As a result, the orientation of the plate member 121 is also stably maintained in the horizontal position, and the mounting surface 127 is stably maintained in a substantially horizontal direction. This allows the abutment surface of the link mechanism 6 (more specifically, the lower link 11) to be stably placed on the mounting surface 127.

[0058] (4) Other The present invention is not limited to the above-described embodiment, and various modifications and substitutions are possible within the scope of the spirit and technical concept of the present invention.

[0059] For example, the support pillars 18, 19 provided on the support tower 8 are constructed by combining bolts and washers, but the configuration, shape and number of the support parts are not limited to this, and it is sufficient if they can limit the distance between the rotation operating member 120 and the support tower 8. Furthermore, although the above description has been given using an example in which the support tower 8 constitutes the support, if a separate member is interposed between the support tower 8 and the link mechanism 6, the support can be constituted by the support tower 8 and that separate member.

[0060] Furthermore, the rotation center k of the rotation operation member 120 is located on the straight line connecting the support columns 17 and 19 provided on the support tower 8, and this straight line is perpendicular to the straight line connecting the rotation center k and the support column 18, but this is not limited to this. In other words, the arrangement of the support columns 17, 18, and 19 is sufficient as long as the rotation operation member 120 can be inserted and removed by rotating the rotation operation member 120.

[0061] Furthermore, the shape of the plate member 121 of the rotation operation member 120 is generally spindle-shaped, diamond-shaped, or generally elliptical, but is not limited to this and any shape that can limit separation by the support pillars 17, 18, and 19 of the support tower body 8 will suffice. Furthermore, the structure and position of the engaging member 21 are not limited to the above-mentioned embodiment as long as it can restrict unintentional separation between the rotation operation member 120 and the support tower body 8.

[0062] <About the problem to be solved and the effects of the invention> The problems to be solved by the invention and the effects of the invention are not limited to those described above. That is, the present invention may solve problems or achieve effects not described above, or may solve only some of the problems or achieve only some of the effects described above.

[0063] <About shape, numbers, structure, and time series> The components illustrated in the embodiments and drawings may be modified and improved as desired within the scope of the technical concept of the present invention in terms of shape, numerical value, or the structure or chronological relationship of multiple components.

[0064] <Vertical / Plumb> Furthermore, the terms "vertical" and "plumb" in the above explanation do not mean "vertical" in the strict sense. In other words, "vertical" means "substantially vertical" or "substantially plumb," allowing for design and manufacturing tolerances and errors.

[0065] <parallel> Furthermore, "parallel" in the above description does not mean parallel in the strict sense. In other words, "parallel" means "substantially parallel," allowing for tolerances and errors in design and manufacturing.

[0066] <equal to> Furthermore, the term "equal" in the above description does not have a strict meaning. In other words, "equal" means "substantially equal," allowing for tolerances and errors in design and manufacturing.

[0067] In addition to the above, the methods according to the above embodiments and modifications may be used in appropriate combination.

[0068] Although not specifically illustrated, the present invention can be implemented with various modifications within the scope of the invention. [Explanation of symbols]

[0069] 1. Hydraulic excavator (construction machinery) 2 Undercarriage (car body) 3 Upper rotating body (car body) 5 Cab (operator's compartment) 6 Link mechanism 7 Cab lift drive cylinder (lift drive unit) 8 Support tower body (support body) 10 Top Link 11 Link below 16 Lowering regulation mechanism 17 Support part (spacing member) 18 Support column (engaging protrusion) 19 Support part (spacing member) 21 Engagement member 120 Rotation operating member 121 Plate member (contact part) 122 Gripping part 123 Pin section 124 Locking claw 125 engagement hole 126 Stepped section 127 Placement surface k rotation center

Claims

1. The car body and a driver's cab provided on the vehicle body; a lifting drive unit that lifts and lowers the operator cab; a link mechanism for maintaining the operator's cab, which is raised and lowered by the lift drive unit, in a predetermined position; a support body that supports the link mechanism; a descent restriction mechanism that restricts the descent of the operator cab at a predetermined descent restriction position; In construction machinery having The downward restriction mechanism is The rotary operating member is provided so as to be rotatable relative to the support and so as to be movable in a direction perpendicular to the rotation direction toward and away from the link mechanism, and is rotatable between a first angular position where the rotary operating member moves toward the link mechanism to prevent the lowering of the cab, and a second angular position where the rotary operating member moves away from the link mechanism to release the prevention of the lowering of the cab. Construction machinery characterized by:

2. 2. The construction machine according to claim 1, The rotation operation member is a protruding pin portion that is inserted into the support body, that protrudes from the support body toward the link mechanism at the first angular position, and that is released from the protruding state at the second angular position; an abutment portion that is integrally formed with the protruding pin portion and is provided on the opposite side of the support body from the link mechanism, the abutment portion abutting the support body at the first angular position and being separated from the support body at the second angular position; have Construction machinery characterized by:

3. 3. The construction machine according to claim 2, The second angular position is defined by a distance maintaining member that maintains the contact portion spaced from the support body. Construction machinery characterized by:

4. 3. The construction machine according to claim 2, The rotary operating member further includes an engaging member configured to be engageable with and disengageable from the contact portion, and which engages with the contact portion at the second angular position to prohibit rotation of the rotary operating member. Construction machinery characterized by:

5. 3. The construction machine according to claim 2, The abutment portion is The locking mechanism has a generally spindle-like or generally elliptical shape in which the longitudinal dimension is greater than the lateral dimension in a plan view, and has an elongated engagement hole on one side of the rotation center in the longitudinal direction, The support body is provided with an engagement protrusion that engages with the engagement hole at the first angular position. Construction machinery characterized by:

6. 6. The construction machine according to claim 5, A construction machine characterized in that the long axis direction of the engagement hole and the short side direction of the abutment portion are approximately aligned.

7. 6. The construction machine according to claim 5, The protruding pin portion is a stepped portion that forms a mounting surface that is substantially horizontal when the rotation operation member is in a first angular position; The placement surface is At the first angular position, the support member abuts against the link mechanism from below on the link mechanism side. Construction machinery characterized by:

8. The construction machine according to claim 7, A construction machine characterized in that the minor axis direction of the engagement hole and the surface direction of the mounting surface are approximately parallel.

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