US-12624520-B2 - Construction machine

Abstract

A construction machine is capable of returning the posture of an earth removal plate (blade) from a rocking posture to a predetermined normal posture. A stay is mounted on the construction machine body to move in upward and downward directions. The earth removal plate is mounted on the distal end portion of the stay, and is rockably movable in forward and rearward directions by an angle cylinder controlled by a flow of hydraulic fluid in response to receiving an instruction about rocking the earth removal plate. A normalization switch gives an instruction to set the posture of the earth removal plate to a predetermined normal posture from the rocking posture. The posture of the earth removal plate is set to the predetermined normal posture from the rocking posture in response to the instruction from the normalization switch.

Inventors

• Keisuke SAKISAKA
• Masayuki Yunoue
• Masaya HARADA
• Takuya Nomura

Assignees

• HITACHI CONSTRUCTION MACHINERY TIERRA CO., LTD.

Dates

Publication Date

20260512

Application Date

20220118

Priority Date

20210311

Claims (2)

1. 1 . A construction machine comprising: a stay mounted, on a machine body, turnably in upward and downward directions; an earth removal plate mounted, on a distal end portion of the stay, rockably in forward and rearward directions; an angle cylinder for rocking the earth removal plate in forward and rearward directions; a control valve for controlling a flow of hydraulic fluid flowing from a hydraulic pump to the angle cylinder; an operation unit for giving an instruction about rocking action of the earth removal plate in forward and rearward directions; and a controller for controlling the control valve in response to the instruction from the operation unit, wherein the construction machine includes a normalization switch for giving an instruction to the controller to set a posture of the earth removal plate to a predetermined normal posture from a rocking posture for rocking the earth removal plate in forward and rearward directions, a pressure sensor for sensing a load pressure on the angle cylinder, and a buzzer, the controller is configured to: compute a stroke of the angle cylinder and store the computed stroke on a basis of an instruction signal from the operation unit; control the control valve to set a stroke of the angle cylinder to a preset normal stroke in response to the instruction from the normalization switch; and stop controlling the control valve and energize the buzzer when the load pressure sensed by the pressure sensor is higher than a predetermined threshold value in controlling the control valve in response to the instruction from the normalization switch.
2. 2 . The construction machine according to claim 1 , wherein the operation unit includes a pushbutton-type first operation switch for giving instruction about rocking one side of the earth removal plate when pressed shortly, and a pushbutton-type second operation switch for giving instruction about rocking another side of the earth removal plate when pressed shortly, and at least one of the first operation switch and the second operation switch doubles as the normalization switch for setting the posture of the earth removal plate, from the rocking posture, to the predetermined normal posture when pressed long.

Description

TECHNICAL FIELD The present invention relates to a construction machine including an earth removal apparatus. BACKGROUND ART Hydraulic excavators that belong to a category of construction machines generally include a lower track structure that is able to travel on its own and an upper swing structure swingably mounted on an upper side of the lower track structure. The lower track structure and the upper swing structure jointly make up a machine body. The upper swing structure includes a work implement for performing an earth excavation work or the like. The lower track structure includes an earth removal apparatus for performing an earth removal work or the like. For example, Patent Document 1 discloses an earth removal apparatus that includes a stay disposed, on a front side of a lower track structure, turnably in upward and downward directions, an earth removal plate (blade) mounted, on a distal end portion of the stay, rockably in forward and rearward directions about a pin shaft (joint pin) extending in upward and downward directions, a lifting and lowering cylinder (blade cylinder) for turning the stay in the upward and downward directions to lift and lower the earth removal plate, and an angle cylinder for rocking the earth removal plate in the forward and rearward directions. While the stay is turned downwardly to keep the earth removal plate in contact with the ground, the hydraulic excavator is driven to travel, enabling the earth removal plate to push soil on the ground for leveling the land. At this time, if the posture of the earth removal plate is set to a predetermined normal posture (stated in detail, a posture in which the earth removal plate has its longitudinal directions oriented perpendicularly to the direction in which the hydraulic excavator moves straight ahead), then it is possible for the earth removal plate to level the land by discharging soil to both left and right sides thereof. If the earth removal plate is rocked to one side to have such a rocking posture that the earth removal plate has a left end portion positioned rearwardly and has a right end portion positioned forwardly, then it is possible for the earth removal plate to level the land while discharging soil to the left side thereof. Alternatively, if the earth removal plate is rocked to the other side to have such a rocking posture that the earth removal plate has the left end portion positioned forwardly and the right end portion positioned rearwardly, then it is possible for the earth removal plate to level the land while discharging soil to the right side thereof. PRIOR ART DOCUMENT Patent Document Patent Document 1: JP-2013-181274-A SUMMARY OF THE INVENTION Problem to be Solved by the Invention However, the prior art described above has room left for improvement as follows. According to the prior art, when the posture of the earth removal plate is to be returned from the rocking posture to the predetermined normal posture depending on the progress of the land leveling work, it has been customary for the operator to adjust the posture of the earth removal plate by operating an operation unit while confirming the posture of the earth removal plate. Therefore, it has not been easy to return the posture of the earth removal plate from the rocking posture to the predetermined normal posture. It is an object of the present invention to provide a construction machine that makes it possible to easily return the posture of an earth removal plate from a rocking posture to a predetermined normal posture. Means for Solving the Problem In order to achieve the above object, there is provided in accordance with the present invention, there is provided a construction machine including a stay mounted, on a machine body, turnably in upward and downward directions, an earth removal plate mounted, on a distal end portion of the stay, rockably in forward and rearward directions, an angle cylinder for rocking the earth removal plate in forward and rearward directions, a control valve for controlling a flow of hydraulic fluid flowing from a hydraulic pump to the angle cylinder, an operation unit for giving an instruction about rocking action of the earth removal plate in forward and rearward directions, and a controller for controlling the control valve in response to the instruction from the operation unit, in which the construction machine includes a normalization switch for giving an instruction to the controller to set a posture of the earth removal plate to a predetermined normal posture from a rocking posture for rocking the earth removal plate in forward and rearward directions, and the controller controls the control valve to set the posture of the earth removal plate to the predetermined normal posture from a rocking posture for rocking the earth removal plate in forward and rearward directions, in response to the instruction from the normalization switch. Advantage of the Invention According to the present invention, it is easy