JP2020023811A - Cab front step structure of construction machine - Google Patents

Abstract

To provide a cab front step structure of a construction machine that can maintain both operator visibility and maintenance workability during excavation work at a high level.SOLUTION: A cab 7 on which an operator rides is installed on a cab head 6 of an excavator 1, and fixed steps 17 are provided as passages on both right and left sides of the cab 7 and extend forward. A guide rail 20 is fixed to a lower surface of an extension 17a of each fixed step 17, and a movable step 18 is guided to the right and left, and can be slid in the contact and separation directions according to the expansion and contraction of an electric cylinder 22. At the time of maintenance work such as cleaning of a front window 15 of the cab 7, the right and left movable steps 18 are moved closer to each other and positioned in front of the cab 7 (deployed position). During excavation work of the excavator 1, the right and left movable steps 18 are separated from each other and overlap the lower side of the fixed step 17 (storage position), so that the operator can easily visually recognize a work place located diagonally downward and forward.SELECTED DRAWING: Figure 4

Description

  TECHNICAL FIELD The present invention relates to a pre-cab step structure of a construction machine serving as a scaffold for maintenance work and the like.

  For example, in a large construction machine such as a hydraulic shovel having an operating mass of 100 t or more, a cab (operating cab) is installed at a high place on a cab bed containing an air conditioner and the like. Therefore, when performing maintenance work such as cleaning the front window of the cab or replacing the front extinction lamp, the worker cannot reach the cab. Therefore, in such a large construction machine, a step is provided below the front window of the cab, and an operator stands on the step to perform a maintenance operation.

  However, as the cab is located at a higher position, the operator in the cab is more likely to look down on the work place, and a part of the operator's line of sight obliquely downward and forward is obstructed by the steps. Is not preferred.

  Therefore, as described in Patent Document 1, for example, while the base end of the step is connected to a rotating portion provided on the cab bed and supported in a horizontal posture, the step is moved upward around the rotating portion by driving a hydraulic cylinder. There has been proposed a hydraulic excavator that can be switched to a storage position that has been rotated. When performing maintenance work, keep the steps in a horizontal position and use them as a scaffold, and during excavation work of the excavator, turn the steps around the turning part to the storage position to secure the operator's line of sight are doing.

JP 2017-88034 A

  However, the step structure before cab of Patent Literature 1 in which the step is a rotary type has room for further improvement in ensuring both visibility of the operator and maintenance workability during excavation work of the hydraulic excavator.

  That is, the steps are switched to the storage position during the excavating operation of the excavator, and the steps at this time are overlapped on the front surface of the cab. For this reason, when the front and rear widths of the steps are wide, the lower part of the front window is covered, and particularly the lower part of the line of sight of the operator is obstructed. If the width before and after the step is reduced with priority given to securing the field of view, the standing position of the worker performing the maintenance work is restricted, so that the maintenance workability is reduced. Accordingly, there is a trade-off between securing the visibility of the operator and maintenance workability, and there has been a demand for a measure that can achieve both.

  The present invention has been made in order to solve such problems, and an object of the present invention is to provide a construction machine capable of achieving both a high level of visibility and maintenance workability of an operator during excavation work. It is to provide a pre-cab step structure.

  In order to achieve the above object, a cab pre-step structure of a construction machine according to the present invention, in a construction machine provided with a cab on which an operator rides, is extended forward by a predetermined dimension on a front side of the cab and a front side of the front side. A fixed step, a movable step guided by a guide rail provided in the fixed step, and slidable between a deployed position located on the front side of the cab and a storage position overlapped with the fixed step; And a driving means for switching between a deployed position and a stored position.

  ADVANTAGE OF THE INVENTION According to the step structure before cab of the construction machine of this invention, the visibility of an operator during excavation work and the maintenance workability can be made compatible at a high level.

It is a side view which shows the hydraulic shovel to which the step structure before cab of embodiment was applied. FIG. 2 is an enlarged side view of FIG. 1 showing details of a cab of the hydraulic excavator. It is a front view of a cab showing the state where a movable step was made into a deployment position. It is a front view of a cab showing the state where a movable step was made into a storage position. FIG. 5 is a sectional view taken along line VV of FIG. 3 showing a relationship between a guide rail and a movable step.

Hereinafter, an embodiment will be described in which the present invention is embodied in a step structure before a cab of an ultra-large hydraulic excavator operating in a mine or the like.
FIG. 1 is a side view showing a hydraulic shovel to which a step structure before a cab according to the present embodiment is applied.

  A crawler 3 is provided on the lower traveling body 2 of the excavator 1, and the crawler 3 is driven by a traveling hydraulic motor (not shown) to cause the excavator 1 to travel. An upper revolving unit 5 is provided on the lower traveling unit 2 via a revolving unit 4, and the upper revolving unit 5 is revolved by driving a revolving hydraulic motor (not shown) of the revolving unit 4. A front portion of the upper revolving unit 5 is constituted by a cab head 6, an air conditioner and the like are accommodated in the cab head 6, and a cab 7 on which an operator rides is installed on the cab head 6. The rear part of the upper swing body 5 is constituted by a machine room 8, and a counterweight 9 is fixed to the rear side of the machine room 8.

  A working device 10 for digging is attached to the right side of the cab 7 of the upper rotating body 5 so as to face forward, and the working device 10 includes a boom 11, an arm 12 and a bucket 13. The angle of the boom 11 is changed by a boom cylinder 11a, the angle of the arm 12 is changed by an arm cylinder 12a, and the angle of the bucket 13 is changed by a bucket cylinder 13a.

  Although not shown, an HST (Hydro Static Transmission) using an engine as a power source is mounted in the machine room 8, and hydraulic oil is discharged from a hydraulic pump of the HST by driving the engine. When various operating devices installed in the cab 7 are operated by the operator, the hydraulic oil from the hydraulic pump is switched to the above-described traveling and turning hydraulic motors and the cylinders 11a to 13a of the working device 10 and the like. The hydraulic excavator 1 is supplied as needed, and the hydraulic excavator 1 operates.

  FIG. 2 is an enlarged side view of FIG. 1 showing details of the cab 7 of the excavator 1, FIG. 3 is a front view of the cab 7 showing a state where the movable step is in a deployed position, and FIG. FIG. 5 is a sectional view taken along the line VV in FIG. 3 showing the relationship between the guide rails and the movable steps.

  In particular, as shown in FIGS. 2 and 3, a front window 15 is provided at an upper portion of a front surface of the cab 7, and a lateral window 16 (only the left side is shown) is provided at an upper portion of left and right side surfaces of the cab 7. The operator riding in the cab 7 can visually recognize the outside through the windows 15 and 16, and in particular, the operator during the excavation work can view the situation of the work site located diagonally downward and forward through the front window 15, such as ore and earth and sand. And the movement of the bucket 13 are visually recognized. In order to carry out maintenance work such as cleaning of the windows 15 and 16 of the cab 7 or replacement of a headlight (not shown), the left and right sides of the cab 7 and the front side of the cab 7 function as passages having handrails 21. Steps 17 and 18 are provided. An elevating device 19 is provided on the left side of the upper revolving unit 5, and an operator or an operator can freely move between the ground surface and the steps 17 and 18 via the elevating device 19.

  The steps 17 and 18 are roughly divided into a fixed step 17 and a movable step 18, and although not shown, each is constituted by grating for the purpose of preventing slippage and preventing sediment accumulation. However, the present invention is not limited to this, and each of the steps 17 and 18 may be made of a steel plate.

  The fixed steps 17 are disposed on the left and right sides of the cab 7 in a horizontal posture, respectively, and extend forward by a predetermined dimension (corresponding to the front-rear width of the movable step 18) from the front surface of the cab 7 (hereinafter referred to as extended). (Referred to as a portion 17a, which corresponds to the fixing step of the present invention). Accordingly, the extending portions 17a of the left and right fixing steps 17 are substantially square in plan view, and are disposed on the front side of the cab 7 and on the left and right sides shifted in the left-right direction (vehicle width direction).

  As shown in FIGS. 3 and 5, guide rails 20 are fixed to the lower surfaces of the extending portions 17a of the left and right fixing steps 17, respectively. The base surface 20a of each guide rail 20 has a substantially square shape corresponding to the extension portion 17a of the fixing step 17 in a plan view, and is superimposed on the extension portion 17a from below. The front edge of each base surface 20a is integrally formed with a wall-shaped toe stopper 20b protruding upward to prevent an operator standing on the extension 17a of the fixing step 17 from inadvertently jumping forward. I have.

  Rail ridges 20c each having an L-shaped cross section project downward from both front and rear edges of each base surface 20a, and the front and rear edges of each base surface 20a approach each other by these rail ridges 20c. A pair of rail grooves 20d that open in the direction in which the rail groove is formed is formed.

  The movable steps 18 are respectively arranged in a horizontal posture below the left and right guide rails 20 configured as described above, and the movable steps 18 are guided in the left-right direction by the guide of the guide rails 20.

  The base surface 18a of each movable step 18 is superimposed on the base surface 20a of the guide rail 20 from below, and its front and rear edges are fitted into front and rear rail grooves 20d. Rail ridges 18c each having an L-shaped cross section project downward from both front and rear edges of the base surface 18a of each movable step 18, and these rail ridges form front and rear edges of each base surface 18a. A pair of rail grooves 18d that open in directions away from each other are formed, and the rail protrusions 20c of the guide rails 20 are fitted therein. As a result, the left and right movable steps 18 can be guided and slid in the left and right directions while being held by the guide rails 20.

  A bracket 23 is fixed to the lower surface of the rail ridge 18 c on the rear side of each movable step 18, and one end of an electric cylinder 22 (corresponding to the driving means of the present invention) is connected to each bracket 23 via a shaft 24. It is connected rotatably. Further, shafts 26 are fixed to both left and right side surfaces of the cab head 6 via bearings 25, and the other ends of the electric cylinders 22 are connected to the respective shafts 26 so as to be relatively rotatable. As is well known, the electric cylinder 22 is an actuator that converts the rotation of a built-in motor into a linear motion by a feed screw and performs an expansion and contraction operation.

  The left and right electric cylinders 22 are always driven in the same direction, and the left and right movable steps 18 slide in the approaching direction when driven in the retracting direction, and move away in the extending direction. At the stroke end of each electric cylinder 22 in the retracting direction, as shown in FIG. 3, the movable steps 18 approaching each other are abutted from the left and right and are located on the front side of the cab 7. Name. At the stroke end of each electric cylinder 22 in the extension direction, as shown in FIG. 4, the movable steps 18 separated from each other overlap the lower side of the fixed step 17, respectively, and this state is hereinafter referred to as a storage position.

  Although details will be described later, maintenance work such as cleaning of the front window 15 and replacement of the headlight is carried out by the worker standing on the movable step 18 in the deployed position, and is movable for the convenience of the worker at that time. Step 18 has a sufficiently wide front and rear width. As the left and right movable steps 18 approach, the left and right overlap between the movable step 18 and the guide rail 20 decreases. However, even in the deployed position, each movable step 18 continues to be held by the guide rail 20 and serves as a step. Perform functions without problems.

  The switching of the movable step 18 is performed by switching switches (not shown) provided on the left and right side surfaces of the cab 7, respectively. Each time the switching switch is pressed, each electric cylinder 22 is driven in a retracting direction or an extending direction to move the movable step. 18 is switched between the development position and the storage position.

  In addition, a wall-shaped toe stop 18b protruding upward is integrally formed with the front edge of the rail ridge 18c on the front side of each movable step 18, so that an operator standing on the movable step 18 in the unfolded position is inadvertently forward. Is prevented from jumping out.

  The handrails 21 of the left and right fixing steps 17 are configured by extending a steel pipe vertically and horizontally, including the extending portions 17a, but the front side of the cab 7, that is, the position corresponding to the movable step 18 in the deployed position is left and right. It consists of only one steel pipe 21a that connects the upper parts of the handrails 21 on the fixing step 17 to each other. Although consideration is given to minimizing the situation in which the line of sight of the operator riding on the cab 7 is blocked by the handrail 21, the function as the handrail 21 can be performed without any problem.

Next, the operation of the pre-cab step structure configured as described above will be described.
Basically, the movable step 18 is switched to the deployed position when performing maintenance work, and is switched to the storage position during excavation work of the excavator 1.

  The worker performing the maintenance work climbs from the surface of the cab 7 via the elevating device 19 onto the fixed step 17 on either side of the cab 7, and presses the changeover switch when the movable step 18 is in the storage position shown in FIG. . The movable step 18 is switched to the unfolded position shown in FIG. 3 by driving the electric cylinder 22 in the retracted direction, and the operator stands on the movable step 18 to clean the front window 15 of the cab 7 and perform maintenance such as exchanging the front light off. Perform the work.

  As described above, since the movable step 18 has a sufficiently wide front and rear width, the worker can easily perform the work at the optimum position according to the work content without restricting the standing position. Maintenance workability can be improved. When the operation is completed, the operator presses the changeover switch again, and the movable step 18 is switched to the storage position shown in FIG. 4 by driving the electric cylinder 22 in the extending direction.

  On the other hand, the operator who performs the excavation work of the excavator 1 gets on the cab 7 through the fixing step 17 from the elevating device 19. Although the movable step 18 should have been returned to the storage position after the maintenance work as described above, the operator may forget the movable step 18 in the deployed position. Is operated by pressing the changeover switch. The movable step 18 is switched to the storage position by driving the electric cylinder 22, whereby the space on the front side of the cab 7 is opened downward as shown by the phantom line in FIG.

  In the technique of Patent Literature 1 in which the step is rotated, if the front and rear widths of the step are enlarged, the lower part of the front window is covered by the step that is rotated upward. On the other hand, since the movable step 18 of the present embodiment is superimposed on the lower side of the fixed step 17 in the storage position, even if the front-rear width of the movable step 18 is enlarged, the front window is not affected at all. 15 is kept in good visibility. Therefore, the operator can easily visually recognize the situation of the work place located diagonally forward and downward through the front window 15, for example, the state of excavation of ore, earth and sand, the movement of the bucket 13, and the like, and efficiently perform excavation work. Can be.

  As a result, according to the pre-cab step structure of the present embodiment, it is possible to achieve both a high level of operator visibility and maintenance workability during excavation work.

  On the other hand, in the present embodiment, the pair of movable steps 18 are slid in the approaching / separating direction. For example, the single movable step 18 is moved to the storage position overlapping the right or left fixed step 17 and the front side of the cab 7. Can be slid to and from the deployed position. The present invention includes such a configuration, and as in the embodiment, it is possible to ensure both visibility of the operator and maintenance workability. However, since a long movable step 18 corresponding to the left and right width of the cab 7 is required, when the movable step 18 is overlaid on the fixed step 17 in the storage position, it protrudes to the side and the electric cylinder 22 as a drive source has a long stroke. Is required.

  Generally, lateral windows 16 are provided on the left and right side surfaces of the cab 7 of the excavator 1, and fixing steps 17 are provided on both sides of the cab 7 for maintenance work. For this reason, if the movable step 18 is divided into right and left as in the present embodiment and is individually overlapped with the left and right fixed steps 17 in the storage position, the movable step 18 is prevented from protruding and the influence on peripheral devices is reduced. In addition to this, it is possible to obtain an effect that the stroke of the electric cylinder 22 can be shortened to realize a smooth operation of the movable step.

  The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the electric cylinder 22 is used as the driving source, but the driving source is not limited to this. For example, a rack extending in the left-right direction is formed on the movable step 18 to mesh with the pinion, and the pinion is rotated and driven by a motor instead of the electric cylinder 22 so that the movable step 18 slides through the rack. Is also good.

1 Hydraulic excavator (construction equipment)
6 Cab head 7 Cab 17a Extension location (fixing step)
18 Movable step 20 Guide rail 22 Electric cylinder (drive means)

Claims (3)

In a construction machine with a cab on which an operator rides,
A fixing step extending forward by a predetermined dimension from the front side of the cab and from the front side,
A movable step slidable between a deployed position located on the front side of the cab and a storage position overlapped with the fixing step, guided by a guide rail provided in the fixing step,
And a drive means for switching the movable step between an unfolded position and a stored position. The movable step is a pair of movable steps slidable in the approaching / separating direction. The cab pre-step structure of a construction machine according to claim 1, wherein the cab is superimposed on a pair of fixing steps disposed on both sides of the cab. The driving means is a cylinder having one end connected to the movable step and the other end connected to a cab head on which the cab is installed, and switches the movable step between a deployed position and a stored position by a telescopic operation. The step structure before a cab of a construction machine according to claim 1, wherein:

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