Electrically powered work machine

Abstract

A cable clamp (26) is provided on an upper swing body (3) of a hydraulic excavator (1). The cable clamp (26) supports a power supply cable (91) connected to a power supply port (12A). The cable clamp (26) is supported on the upper swing body (3) via an arm member (23) mounted to the upper swing body (3). A wire (30) is stretched between the cable clamp (26) and the arm member (23). A tension sensor (29) detects a load applied to the wire (30). A controller (16) notifies when a tension of the tension sensor (29) exceeds a prescribed threshold (T1, T2).

Description

Technical Field

[0001] This invention relates to electric work machinery such as electric hydraulic excavators used in various work sites, such as civil engineering, demolition, and underground engineering. Background Technology

[0002] Most construction machinery, such as hydraulic excavators, uses diesel engines as its power source. Hydraulic excavators use hydraulic oil supplied from a hydraulic pump connected to the diesel engine to operate actuators (such as hydraulic cylinders and hydraulic motors) to perform excavation and other operations.

[0003] Generally speaking, compared to gasoline engines that use gasoline as fuel, diesel engines that use light oil as fuel contain a large amount of particulate matter (PM) and nitrogen oxides (NOx) in their exhaust. Therefore, in order to gradually reduce particulate matter and NOx in exhaust, legal restrictions on diesel engines are being rapidly implemented worldwide. Against this backdrop, it is likely that a large number of work machines that do not emit exhaust gases at the work site—namely, electrically powered work machines—will be introduced in the future.

[0004] As an electric work machine, an electric hydraulic excavator is known, for example, which receives power from an external power source, such as a switchboard located at the work site, via a power cable. The electric hydraulic excavator drives an electric motor using the power supplied via the power cable, which in turn operates a hydraulic pump connected to the electric motor. Here, for example, the case where the power cable travels from the external power source along the ground to the electric hydraulic excavator is considered. In this case, the power cable may be run over during the travel of the electric hydraulic excavator, or it may be entangled during the rotation of the upper rotating body.

[0005] Therefore, allowing an electric hydraulic excavator to operate without restriction could damage the power cable or the power supply port connected to the cable. In other words, to protect power-related equipment, an electric hydraulic excavator operating with the power cable connected needs to limit rotational and travel movements, or prevent overloading of the power cable. In contrast, Patent Document 1 describes a self-propelled work machine that supplies power to the machine body via a power cable hanging from the roof. When the tension of the power cable detected by the load limiter exceeds a threshold, the self-propelled work machine in Patent Document 1 prohibits travel or rotation in the current operating direction, but allows travel or rotation in the opposite direction.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-219461 Summary of the Invention

[0009] In Patent Document 1, a load limiter is provided between a load-bearing trolley that moves along a track on the ceiling of the work site and a power supply cable in the self-propelled work machine. However, factors such as the location, configuration, routing method, and length of the power supply cable from the load limiter to the self-propelled work machine vary greatly depending on the operating environment. Therefore, in the case of the technology in Patent Document 1, it is necessary to modify (adjust) the tension detection value of the load limiter or the threshold value used for control according to the current operating environment, which is a cumbersome operation.

[0010] The purpose of this invention is to provide an electric work machine that can reduce the time required to adjust the overload detection device of the power supply cable corresponding to the operating site.

[0011] The electric work machinery of the present invention has a mobile body and a work device mounted on the body. The body has a power supply port for connecting a power supply cable to a power source. The electric work machinery includes: a cable support member disposed on the body and supporting the power supply cable connected to the power supply port; a load detection sensor that detects a state quantity corresponding to the load applied from the power supply cable to the cable support member; and a controller that notifies when the detection value of the load detection sensor exceeds a predetermined threshold.

[0012] According to the present invention, the time required for adjusting the overload detection device of the power supply cable corresponding to the operating site can be reduced. Attached Figure Description

[0013] Figure 1 This is a right view of an electric hydraulic excavator with the power supply cable connected to the power supply port of the upper rotating body.

[0014] Figure 2 From Figure 1 The rear view of the electric hydraulic excavator as seen from the left.

[0015] Figure 3 It is a magnified 3D view showing the driver's cab, counterweight, cable support device, distribution box, power supply cable, etc.

[0016] Figure 4 It is an enlarged left view showing the cab, counterweight, cable support device, distribution box, power supply cable, etc.

[0017] Figure 5 yes Figure 4 Enlarged view of part (V) in the image.

[0018] Figure 6This indicates the state of the cable clamp (cable support component) after it has been displaced away from the arm component (vehicle side support component), and is related to... Figure 5 This is a magnified view of the same location.

[0019] Figure 7 This is a circuit diagram showing the electric drive system used to drive the hydraulic pump of an electric hydraulic excavator.

[0020] Figure 8 It means by Figure 7 The flowchart shows the processing performed by the controller in the process. Detailed Implementation

[0021] The following example illustrates the application of the implementation method to an electric hydraulic excavator, a representative example of electric work machinery, and will be described in detail with reference to the accompanying drawings.

[0022] It should be noted that, in the following description, the front side of the electric hydraulic excavator 1 is designated as the working device 4 side, and the rear side is designated as the counterweight 7 side, which is opposite to the working device 4 side. Furthermore, the left-right direction of the electric hydraulic excavator 1 is orthogonal to the front-back direction. For example, in... Figure 1 In the diagram, the left-right direction of the paper corresponds to the front-back direction (X-direction) of the electric hydraulic excavator 1, the front-back direction corresponds to the left-right direction (Y-direction) of the electric hydraulic excavator 1, and the top-bottom direction corresponds to the top-bottom direction (Z-direction) of the electric hydraulic excavator 1. Additionally, Figure 8 Each step in the flowchart shown is marked with "S" (e.g., step 1 = "S1").

[0023] The electric hydraulic excavator 1 (hereinafter referred to as hydraulic excavator 1), as an electric work machine, is used, for example, at work sites such as civil engineering, demolition, and underground engineering. The hydraulic excavator 1 of the embodiment is configured, for example, as a small (e.g., with a machine weight of about 1 to 6 tons) hydraulic excavator (electric mini excavator, electric small hydraulic excavator) suitable for operation in confined work sites such as underground engineering projects. Furthermore, the hydraulic excavator 1 of the embodiment is configured as a hydraulic excavator 1 with a cab.

[0024] The hydraulic excavator 1 comprises a self-propelled tracked lower traveling body 2, a rotatable upper rotating body 3 mounted on the lower traveling body 2, and a working device 4 disposed on the upper rotating body 3. The lower traveling body 2 and the upper rotating body 3 constitute the body of the hydraulic excavator 1. The body is capable of both travel and rotation. A swing-type working device 4 is mounted on the front side of the upper rotating body 3 in a swing-like manner. The hydraulic excavator 1 uses the working device 4 to perform tasks such as excavating sand and soil.

[0025] The lower traveling body 2 is configured, for example, to include a track 2A on which multiple track shoes are mounted on a track chain link formed in a circular shape, and left and right travel hydraulic motors (not shown) that drive the hydraulic excavator 1 to travel (self-propelled) by rotating the track 2A. A rotating device consisting of a rotary bearing and a rotary hydraulic motor is provided between the lower traveling body 2 and the upper rotating body 3.

[0026] The working device 4, referred to as the front device, has a swing post 4A located at the front of the rotating frame 5, which is capable of swinging in the left and right directions. A boom 4B is rotatably mounted on the swing post 4A. A stick 4C is rotatably mounted at the front end of the boom 4B. A bucket 4D, serving as a working tool, is rotatably mounted at the front end of the stick 4C. Furthermore, the working device 4 includes a swing cylinder 4E for swinging the swing post 4A, a boom cylinder 4F for rotating the boom 4B, a stick cylinder 4G for rotating the stick 4C, and a bucket cylinder 4H for rotating the bucket 4D, which serves as a working tool cylinder.

[0027] The upper rotating body 3 rotates on the lower traveling body 2, driven by a hydraulic motor that rotates the rotating device. The upper rotating body 3 has a rotating frame 5 as a supporting structure (base frame). The rotating frame 5 houses a cab 6, a counterweight 7, an outer cover 8, an electric motor 9, a hydraulic pump 10, a battery pack 11, and a control valve device (not shown). In this configuration, a working device 4 is mounted on the front of the rotating frame 5. The counterweight 7 is mounted on the rear of the rotating frame 5.

[0028] The cab 6 is located on the left side of the rotating frame 5. The cab 6 is box-shaped, surrounded by a front surface 6A, a rear surface 6B, a left side surface 6C, a right side surface 6D, and an upper surface 6E. The interior of the cab 6 is the operator's cab. Inside the cab 6 are the operator's seat, a travel lever / pedal, and a working lever for operating the hydraulic excavator 1. By operating the travel lever / pedal and working lever, the operator can move the lower traveling body 2, rotate the upper rotating body 3, and dig with the working device 4.

[0029] The counterweight 7 is located at the rear of the cab 6 and at the rear end of the rotating frame 5 in order to achieve weight balance with the working device 4. The counterweight 7 is formed as an arc-shaped weight that extends in the left and right direction and protrudes rearward from the center in the left and right direction. As a result, the rear surface 7A of the counterweight 7 is formed as an arc-shaped surface that is contained within a virtual circle with a fixed rotation radius when the upper rotating body 3 rotates.

[0030] The counterweight 7 rises upwards from the rear end of the rotating frame 5 and covers the battery pack 11 from the rear. A forward-extending extension 7B is formed at the upper end of the counterweight 7. The rear side of the cab 6 is supported by the extension 7B. A distribution box 12 is located on the left end of the extension 7B. A cable support device 21 is located on the right end of the extension 7B. The power supply cable 91, held by the cable support device 21, is connected to the distribution box 12.

[0031] The outer cover 8 is located in front of the counterweight 7 and is mounted on the rotating frame 5. For example... Figure 1 As shown, the outer cover 8, together with the counterweight 7, covers the electric motor 9, hydraulic pump 10, battery device 11, etc. The outer cover 8 is configured to include a right outer cover 8A that covers the electric motor 9, hydraulic pump 10, battery device 11, etc. from the right and top sides, and a left outer cover 8B that covers the battery device 11, etc. from the left side.

[0032] like Figure 3 As shown, the distribution box 12 is located on the left end of the protrusion 7B of the counterweight 7. The distribution box 12 has a power supply port 12A for connecting the power supply cable 91 (e.g., as an inlet for a female connector). An external power source 92 is connected to the power supply port 12A. Figure 7 The power supply cable 91 extends to a power supply connector 91A (e.g., an inlet plug for a male connector). Thus, the upper rotating body 3 has a power supply port 12A for connecting the power supply cable 91. The power supply cable 91 supplies power to the electric motor 9, which serves as a power source. A signal connector 12B is provided in the distribution box 12, located below the power supply port 12A. A signal cable 33 for connecting the tension sensor 29 (described later) to the controller 16 is connected to the signal connector 12B.

[0033] Inside the outer casing 8, in addition to the electric motor 9, hydraulic pump 10, and battery pack 11, there is also a device described later. Figure 7 The diagram shows a rectifier 13, a switch 14, an inverter 15, and a controller 16. The rectifier 13 converts AC power supplied from an external power source 92 into DC power. The switch 14 switches the power supply state between the rectifier 13, the battery pack 11, and the inverter 15. The inverter 15 converts the DC power supplied from the switch 14 into AC power and supplies it to the electric motor 9. Figure 7 As shown, the power supply port 12A, rectifier 13, switch 14, battery pack 11, inverter 15 and electric motor 9 are connected to each other in a way that allows them to be powered through in-vehicle cables.

[0034] Electric motor 9 is the power source of hydraulic excavator 1. Electric motor 9 is mechanically connected to hydraulic pump 10, i.e., in a manner capable of transmitting power (rotation). Hydraulic pump 10 supplies hydraulic oil to various hydraulic actuators (hydraulic cylinders, hydraulic motors) such as boom cylinder 4F via a control valve device. The control valve device is a control valve group consisting of multiple directional control valves. The control valve device distributes the hydraulic oil ejected from hydraulic pump 10 to multiple hydraulic actuators (hydraulic cylinders, hydraulic motors) such as boom cylinder 4F according to the operation of the travel lever / pedal and the work lever. Thus, hydraulic excavator 1 can perform travel, rotation, digging, etc.

[0035] The hydraulic excavator 1 can operate, for example, with the battery pack 11 fully charged, after disconnecting the power connector 91A of the power supply cable 91 from the power supply port 12A of the distribution box 12 and removing the power supply cable 91 from the cable support 21. In this case, the electric motor 9 is driven by power from the battery pack 11. Alternatively, the hydraulic excavator 1 can also operate with the power connector 91A of the power supply cable 91 connected to the power supply port 12A of the distribution box 12 and the power supply cable 91 mounted on the cable support 21. In this case, the electric motor 9 is driven by power from an external power source 92, with any shortfall being driven by power from the battery pack 11.

[0036] When the power supply cable 91 is connected to the power supply port 12A, the hydraulic excavator 1 is maintained in this state for driving, rotating, digging, etc. At this time, the middle part of the power supply cable 91 connected to the power supply port 12A is supported by the cable support device 21. That is, the power supply cable 91 supported by the cable support device 21 is connected to the power supply port 12A of the distribution box 12. The cable support device 21, which is called a cable bracket, has a shaft component 22 and an arm component 23.

[0037] The shaft component 22 is mounted on the upper rotating body 3 (the upper surface of the counterweight 7) with its axis extending vertically. The arm component 23 is mounted on the shaft component 22 in a manner that allows it to rotate about the axis of the shaft component 22 in the vertical direction. The arm component 23 is configured to include a covered cylindrical portion 24 that rotatably engages with the shaft component 22, and a rod portion 25 that extends horizontally from the covered cylindrical portion 24. A cable clamp 26 for holding the power supply cable 91 is provided at the front end of the arm component 23, i.e., at the front end of the rod portion 25.

[0038] The arm component 23 can be fixed to the shaft component 22 at multiple positions in the rotational direction via a locking mechanism (not shown). For example, the arm component 23 is fixed to... Figures 1 to 6The cable holding position is shown. Additionally, although not shown in the diagram, the boom member 23 is fixed in a cab-side receiving position arranged along the right side 6D of the cab 6. Also, although not shown in the diagram, the boom member 23 is fixed in a cab-rear receiving position arranged along the rear surface 6B of the cab 6. The boom member 23 can be selectively fixed in any one of the three positions: the cable holding position, the cab-side receiving position, and the cab-rear receiving position.

[0039] When the hydraulic excavator 1 is operating with the power supply cable 91 connected to the power supply port 12A, the boom component 23 is fixed in... Figures 1 to 6 The cable holding position is shown. That is, the arm component 23 is fixed at the position where the front end of the arm component 23 (rod portion 25) extends from the upper rotating body 3 (rear surface 7A of the counterweight 7). As a result, it is possible to prevent the power supply cable 91 from getting tangled when the hydraulic excavator 1 rotates, and to prevent the power supply cable 91 from being crushed when the hydraulic excavator 1 is traveling.

[0040] exist Figure 5 and Figure 6 The enlarged view shows cable clamp 26, etc. Cable clamp 26 has a pair of clamping parts 26A and 26B that can be opened and closed via a hinge mechanism 26D, and a lock 26C that fixes the clamping parts 26A and 26B in the closed state. The pair of clamping parts 26A and 26B, with the hinge mechanism 26D as the fulcrum, open and close between a closed position where they clamp the power supply cable 91 from the outer periphery and an open position where they release the power supply cable 91. Lock 26C fixes it in the closed position, at the midpoint of holding the power supply cable 91, by locking the pair of clamping parts 26A and 26B.

[0041] like Figure 3 As shown, the power supply cable 91 is held by a cable clamp 26 at the front end of the arm member 23 (rod 25) extending horizontally from the shaft member 22 of the cable support device 21. In this state, the power supply connector 91A, which is the end of the power supply cable 91, is connected to the power supply port 12A of the distribution box 12. Power from the external power source 92 is supplied to the hydraulic excavator 1 via the power supply cable 91, the power supply connector 91A, and the power supply port 12A of the distribution box 12.

[0042] The cable clamp 26 is supported by a bracket 27 located at the front end of the arm member 23 (bar 25). In this case, the cable clamp 26 can be directed relative to the bracket 27 in a predetermined direction (e.g., by means of a spring member 28, which is an elastic member, and a guide member not shown). Figures 4 to 6 It is installed in a manner that allows for displacement in the left and right directions. Additionally, a tension sensor 29, serving as a load detection sensor, is provided on the arm component 23 (rod 25) of the cable support device 21. The tension sensor 29 detects the tension S applied to the steel wire 30.

[0043] The steel wire 30 is positioned between the clamping-side steel wire support 31 fixed to the cable clamp 26 and the vehicle-side steel wire support 32 fixed to the arm component 23 (more specifically, the covered cylindrical portion 24). Thus, the steel wire 30 is fixed to both the cable clamp 26 on the power supply cable 91 side and the arm component 23 (covered cylindrical portion 24) on the vehicle-side.

[0044] The tension of the steel wire 30 varies according to the displacement of the cable clamp 26 relative to the arm member 23 (bar 25). That is, the tension of the steel wire 30 changes as the cable clamp 26 moves away from the arm member 23 (bar 25). Figures 4 to 6 The tension of the wire 30 increases as the cable clamp 26 moves away from the vehicle body. The tension sensor 29 detects the change (tightening, slackening) of the wire 30 according to the displacement of the cable clamp 26. Therefore, the tension sensor 29 can detect not only the load applied to the cable clamp 26, but also the load applied to the power supply cable 91.

[0045] That is, the tension sensor 29 detects the displacement of the cable clamp 26 corresponding to the load applied to the power supply cable 91, based on the tension applied to the steel wire 30. The tension sensor 29 is connected to the controller 16 via the signal cable 33. The tension sensor 29 outputs a signal (tension signal) corresponding to the detected tension to the controller 16. Figure 3 As shown, the signal cable 33 extending from the tension sensor 29 to the controller 16 is provided (introduced) from the vehicle-side wire support 32 fixed to the arm component 23 (covered cylindrical part 24) via the signal connector 12B of the distribution box 12 into the upper rotating body 3. The wire 30, the tension sensor 29, and the controller 16 constitute a cable load detection device (overload detection device) for detecting the load of the power supply cable 91.

[0046] A spring member 28 and a guide member are provided between the cable clamp 26 and the bracket 27 fixed to the arm member 23 (rod 25). The guide member guides the cable clamp 26 relative to the bracket 27 (rod 25). That is, the guide member restricts the displacement of the cable clamp 26 so that the displacement is a linear displacement in one direction (the direction in which the rod 25 extends) relative to the bracket 27. Figures 4 to 6 (in the left and right directions). The guide component may, for example, consist of a convex track (straight component) provided on the bracket 27 and a recess provided on the cable clamp 26 that engages with the track of the bracket 27.

[0047] The spring component 28 extends or shortens according to the displacement of the cable clamp 26. When the hydraulic excavator 1 is operating, the cable clamp 26 extends or shortens according to the load applied to the power supply cable 91. Figures 4 to 6 The cable clamp 26 moves in the left or right direction, and the spring component 28 extends or shortens. For example, when the cable clamp 26... Figure 6As shown, when the cable clamp 26 shifts to the right (away from the vehicle body), the steel wire 30 tightens, and the detection value of the tension sensor 29 increases. Conversely, when the cable clamp 26 shifts to the right (away from the vehicle body), the cable 30 tightens, and the detection value of the tension sensor 29 increases. Figure 5 When the wire 30 shifts to the left (towards the vehicle body), the wire 30 becomes slack, and the detection value of the tension sensor 29 decreases.

[0048] Next, refer to Figure 7 Explain the electric drive system of hydraulic excavator 1.

[0049] like Figure 7 As shown, an external power source 92, such as a commercial power supply located away from the hydraulic excavator 1, supplies power to the electric drive system of the hydraulic excavator 1 via a power supply cable 91. The electric drive system of the hydraulic excavator 1 has the function of supplying power from the external power source 92 to the battery device 11 (charging function) and the function of supplying power from the external power source 92 and / or the battery device 11 to the electric motor 9 (drive function). The power supply to the battery device 11 (charging) and the power supply to the inverter 15 are performed by relays connected to the internal circuit of the switch 14 based on instructions from the controller 16.

[0050] The external power source 92 is, for example, three-phase alternating current (AC). The rectifier 13 converts the three-phase AC power into direct current (DC). When the power connector 91A of the power supply cable 91 is connected to the power supply port 12A of the distribution box 12, power from the external power source 92 can be supplied to the hydraulic excavator 1 via the power supply cable 91 and the power supply port 12A. In this case, power from the external power source 92 can be supplied (charged) to the battery pack 11 via the power supply cable 91, the power supply port 12A, the rectifier 13, and the switch 14. Additionally, power from the external power source 92 can be supplied to the electric motor 9 via the power supply cable 91, the power supply port 12A, the rectifier 13, the switch 14, and the inverter 15. Furthermore, power from the battery pack 11 can be supplied to the electric motor 9 via the switch 14 and the inverter 15.

[0051] The input side of controller 16 is connected to tension sensor 29, monitoring device 34, key switch 35, tachometer 36, charging switch 37, locking switch 38, and battery device 11. The output side of controller 16 is connected to monitoring device 34, alarm 39, battery device 11, switcher 14, and inverter 15. Controller 16 is a vehicle body control controller that controls the movement of hydraulic excavator 1. Controller 16 controls switcher 14 and inverter 15 based on signals (input signals) from key switch 35, tachometer 36, locking switch 38, charging switch 37, monitoring device 34, tension sensor 29, and battery device 11. Thus, controller 16 controls the drive of electric motor 9, which is the drive source of hydraulic excavator 1.

[0052] In addition, the controller 16 controls the monitoring device 34 (information display control) and the alarm (alarm output control). Furthermore, the controller 16 performs necessary control (notification) based on the detected value (tension) from the tension sensor 29. For this purpose, the controller 16 is configured to include a microcomputer. The controller 16 has a memory composed of flash memory, ROM, RAM, EEPROM, etc., and an arithmetic circuit (CPU). The memory stores a control program for performing necessary notifications based on the detected value (tension) from the tension sensor 29, i.e., for executing the functions described later. Figure 8 The processing procedure shown is the processing flow.

[0053] A battery monitoring device is provided in the battery assembly 11. The controller 16 is connected to the battery monitoring device. The battery monitoring device monitors the status of the battery assembly 11 (battery status), such as SOC (state of charge), temperature, and abnormalities. The battery monitoring device outputs signals corresponding to the battery status to the controller 16.

[0054] The monitoring device 34 is a vehicle-mounted monitor. For example, the monitoring device 34 is installed in the cab 6 of the hydraulic excavator 1. The monitoring device 34 displays information that should be conveyed to the operator of the hydraulic excavator 1. For example, the monitoring device 34 displays the operating status of the hydraulic excavator 1, the state of charge (SOC) corresponding to the remaining power of the battery 11, fault information of various equipment, warning messages, the current time, etc. The monitoring device 34 is an information notification device that uses a screen to notify the operator of information.

[0055] The key switch 35 is located, for example, inside the cab 6 of the hydraulic excavator 1. The key switch 35 is a start / stop switch for starting (power on) and stopping (power off) the hydraulic excavator 1. Signals (on signal, off signal) from the key switch 35 are output to the controller 16. The operator can start and stop the hydraulic excavator 1, for example, by inserting a key into the key switch 35 and turning the key.

[0056] The charging switch 37 is located, for example, in the cab 6 of the hydraulic excavator 1 or in the distribution box 12. The charging switch 37 is a switch that selects whether to supply power from the external power source 92 to the battery pack 11 when the power supply cable 91 is connected to the power supply port 12A. That is, the charging switch 37 is a switch that selects whether to charge the battery pack 11. The signals from the charging switch 37 (charging on signal, charging off signal) are input to the controller 16. When the power supply cable 91 is connected to the power supply port 12A, the operator can charge the battery pack 11 by turning on the charging switch 37.

[0057] Locking switch 38 is a detection switch that detects the position of the door lock lever (not shown). Specifically, locking switch 38 detects whether the door lock lever is in a locked position (lifted position) that prohibits the hydraulic actuator of the hydraulic excavator 1 from being driven, or in a locked-out position (lowered position) that allows the hydraulic actuator to be driven. Signals from locking switch 38 (locking signal, locking-out signal) are output to controller 16. The door lock lever is operated by the operator to either the passenger / landing restriction position (lock-out position) that closes (closes) the passenger / landing opening of the cab 6, or the passenger / landing permission position (locked position) that opens (opens) the passenger / landing opening. When the door lock lever is operated to the locked-out position, the hydraulic excavator 1 can drive the hydraulic actuator.

[0058] Based on the judgment of the controller 16, the alarm 39 outputs an alarm sound and a warning voice to the operator. The alarm 39 is an information notification device that notifies the operator of information through sound.

[0059] The speed dial 36 is a dial that variably sets the speed of the electric motor 9. The speed dial 36 is operated by the operator. The speed dial 36 outputs a motor speed command (signal) corresponding to the operator's operation to the controller 16. The controller 16 controls the inverter 15 according to the command from the speed dial. That is, the inverter 15 controls the frequency of the voltage supplied to the electric motor 9 and controls the speed of the electric motor 9 according to the motor speed command from the controller 16.

[0060] A hydraulic pump 10 is connected to an electric motor 9. The hydraulic excavator 1 is driven by supplying working hydraulic oil injected from the hydraulic pump 10 to various hydraulic actuators via a control valve device. The amount of working hydraulic oil injected from the hydraulic pump 10 corresponds to the rotational speed of the hydraulic pump 10. Therefore, the higher the rotational speed of the electric motor 9, the higher the speed of the hydraulic actuators; the lower the rotational speed, the lower the speed of the hydraulic actuators. Furthermore, the hydraulic excavator 1 can be stopped by stopping the rotation of the electric motor 9.

[0061] However, the self-propelled operating machinery described in Patent Document 1 has a load limiter between the load-bearing trolley moving along a track on the ceiling of the work site and the power supply cable. Therefore, in the case of the technology in Patent Document 1, it is necessary to correct (adjust) the tension detection value or control threshold of the load limiter according to the current operating environment. In contrast, the hydraulic excavator 1 of the embodiment includes a cable load detection device (overload detection device) for detecting the load of the power supply cable 91. In this case, in the embodiment, the load of the power supply cable 91 is detected using a cable support device 21, which serves as a support on the vehicle body side. As a result, in the embodiment, the time required to adjust the overload detection device of the power supply cable 91 according to the operating environment can be reduced.

[0062] That is, according to the embodiment, the hydraulic excavator 1 is powered by an external power source 92 via a power supply cable 91. In other words, the hydraulic excavator 1 is charged and driven by power supplied from outside the hydraulic excavator 1. The hydraulic excavator 1 includes a power supply port 12A (cable connector) for connecting the power supply cable 91, a cable support device 21 for supporting the power supply cable 91 guided to the power supply port 12A, a tension sensor 29 serving as a load detection sensor for detecting the load applied to the power supply cable 91, and a controller 16 serving as a control device for inputting the detection value of the tension sensor 29. The detection value of the tension sensor 29 corresponds to the load on the power supply cable 91. The controller 16 limits or controls the drive of the hydraulic excavator 1 based on the detection value (load) of the tension sensor 29.

[0063] Here, the cable support device 21 is supported on the vehicle body in a manner that allows it to extend from its mounting position on the vehicle body. That is, the cable support device 21 extends from the side or rear of the cab location of the arm component 23 towards the vehicle body. Figures 1 to 6 Rotating the cable holding position as shown allows the front end of the arm component 23 to extend from the upper rotating body 3. Tension sensor 29 detects the load applied to the cable support device 21. Specifically, the power supply cable 91 is supported by a cable clamp 26 located at the front end of the arm component 23. The load on the cable clamp 26 directly corresponds to the load on the power supply cable 91. Tension sensor 29 detects the tension (change) of the wire 30 (variable component) corresponding to the load on the cable clamp 26.

[0064] like Figure 5 and Figure 6 As shown, the detection value of tension sensor 29 is set to S, and the displacement of cable clamp 26 mounted on arm assembly 23 via spring assembly 28 from its initial position is set to X. The tension of wire 30 varies according to the displacement X of cable clamp 26. That is, the detection value S of tension sensor 29 is proportional to the displacement X of cable clamp 26; the greater the displacement X of cable clamp 26 (displacement X in the direction away from the vehicle body), the greater the tension (detection value S) of wire 30. Controller 16 issues a notification (warning to the operator, restriction of operation of hydraulic excavator 1) when the tension (detection value S) of wire 30 exceeds a predetermined value (first threshold T1, second threshold T2).

[0065] In this embodiment, the displacement X1 of the cable clamp 26 is set as a first allowable value, and the detection value S of the tension sensor 29 when the displacement X of the cable clamp 26 is the first allowable value X1 is set as T1. Furthermore, the displacement X2 of the cable clamp 26 is set as a second allowable value, and the detection value S of the tension sensor 29 when the displacement X of the cable clamp 26 is the second allowable value X2 is set as T2. The tension T1 corresponding to the first allowable value X1 serves as a threshold (first threshold T1) for whether to issue an alarm and limit the rotational speed of the electric motor 9. The tension T2 corresponding to the second allowable value X2 serves as a threshold (second threshold T2) for issuing an alarm and stopping the rotation of the electric motor 9.

[0066] When the displacement X of the cable clamp 26 is less than X1 (X < X1), that is, when the detection value S of the tension sensor 29 is lower than the first threshold T1 (S < T1), the load applied to the power supply cable 91 is small. In this case, the controller 16 does not issue an alarm. In addition, the controller 16 does not limit the speed of the electric motor 9. In contrast, when the displacement X of the cable clamp 26 is greater than or equal to X1 and less than X2 (X1 ≤ X < X2), that is, when the detection value S of the tension sensor 29 is greater than or equal to the first threshold T1 and lower than the second threshold T2 (T1 ≤ S < T2), the load applied to the power supply cable 91 is large.

[0067] In this case, the controller 16 issues an alarm via the alarm 39 and the monitoring device 34, and limits the rotational speed of the electric motor 9. Furthermore, when the displacement X of the cable clamp 26 is X2 or greater (X2 ≤ X), that is, when the detection value S of the tension sensor 29 is a second threshold T2 or greater (T2 ≤ S), the load applied to the power supply cable 91 becomes larger. In this case, the controller 16 issues an alarm via the alarm 39 and the monitoring device 34, and simultaneously stops the rotation of the electric motor 9.

[0068] The first threshold T1 and the second threshold T2 are determined in advance through experiments, calculations, simulations, etc., to be values ​​that can suppress damage to the power supply cable 91 and the power supply port 12A. In this case, the first threshold T1 can be set, for example, to 70 to 80% of the maximum permissible tension corresponding to the maximum permissible load of the power supply cable 91 or the power supply port 12A, and the second threshold T2 can be set, for example, to 90 to 95% of the maximum permissible tension corresponding to the maximum permissible load of the power supply cable 91 or the power supply port 12A.

[0069] In this embodiment, the load of the power supply cable 91 is detected within a specific section of the vehicle. Specifically, the load of the power supply cable 91 is detected by detecting changes in the tension of the wire 30 between the clamping side wire support 31 and the vehicle body side wire support 32. Therefore, in this embodiment, it is possible to eliminate the need to adjust the threshold and detection value based on differences in cable length, installation location, etc., depending on the operating environment. It should be noted that the control of the controller 16 in issuing notifications corresponding to the detection value of the tension sensor 29 will be described in detail later. Figure 8 The control process is shown.

[0070] The hydraulic excavator 1 of the embodiment has the structure described above, and its operation will be explained next.

[0071] For example, if an external power source 92 is available at the work site, a power supply cable 91 extending from the external power source 92 is connected to the power supply port 12A of the hydraulic excavator 1. Power from the external power source 92 is then supplied to the electric motor 9 via a rectifier 13, a switch 14, and an inverter 15. Additionally, power from the external power source 92 can also charge the battery pack 11. The electric motor 9 drives the hydraulic pump 10 using power from the external power source 92 and / or the battery pack 11.

[0072] Here, when the hydraulic excavator 1 is driven by electricity from an external power source 92, such as Figures 1 to 6 As shown, the hydraulic excavator 1 is operated with the power cable 91 supported at its midpoint by the cable support device 21. That is, in this state, the hydraulic excavator 1 is moved by the operator operating the travel lever / pedal. Additionally, the operator operates the work lever to rotate the upper rotating body 3 while simultaneously performing excavation work such as digging sand or soil using the work device 4. At this time, depending on the direction of the hydraulic excavator 1's movement and the relationship between the length of the power cable 91 and the position of the external power source 92, a relatively large force may sometimes be applied to the power cable 91. The controller 16 of the hydraulic excavator 1 issues a notification corresponding to threshold T1 or threshold T2 when the detection value S of the tension sensor 29 exceeds a predetermined threshold T1 or threshold T2.

[0073] Next, refer to Figure 8 This explains the control processing performed by controller 16, specifically the control processing that notifies the system based on the detection value S from tension sensor 29. It should be noted that... Figure 8 The control processing is repeated at a specified control cycle (e.g., 10 ms) during the period when the controller 16 is powered on.

[0074] For example, when the controller 16 is activated by turning on the key switch, Figure 8The control process begins. Controller 16 reads the detection value S from tension sensor 29 in S1. Next, in S2, the detection value S read in S1 is compared with a first threshold T1. That is, it is determined whether the detection value S is greater than or equal to the first threshold T1 (T1≤S). If the determination in S2 is "yes," meaning the detection value S is greater than or equal to the first threshold T1 (T1≤S), the process proceeds to S3. In S3, an alarm is activated. For example, in S3, a warning is displayed on the monitor 34 and / or an alarm sound or warning voice is emitted from alarm 39 to notify the operator.

[0075] In S4, following S3, the speed of the electric motor 9 is limited to a low speed. That is, the controller 16 reduces the speed command to the inverter 15 and decreases the drive speed of the hydraulic excavator 1. In this case, the speed (rotational speed) of the electric motor 9 is limited to a value that will not cause a sharp increase in the load on the power supply cable 91 or the power supply port 12A even if the hydraulic excavator 1 continues to be driven. For example, this speed is limited to 20 to 50% of the speed set by the speed dial 36.

[0076] If the speed of electric motor 9 is limited to a low speed in S4, then proceed to S5. In S5, the detection value S read in S1 is compared with the second threshold T2. That is, it is determined whether the detection value S is greater than or equal to the second threshold T2 (T2≤S). If the determination in S5 is "no", that is, the detection value S is less than the second threshold T2 (T2>S), then proceed to the end step. That is, after the end step, proceed to the start step and repeat the processing after S1.

[0077] In contrast, when the judgment in S5 is "yes," meaning the detected value S is above the second threshold T2 (T2≤S), proceed to S6. In this case, it can be considered that the load on the power supply cable 91 or the power supply port 12A has reached or exceeded the allowable value. Therefore, the electric motor 9 is stopped in S6. That is, the controller 16 sets the speed command for the inverter 15 to 0 and stops the drive of the hydraulic excavator 1. Thus, as long as the detected value S is not lower than the second threshold T2, the drive of the hydraulic excavator 1 is prohibited, thereby preventing damage to the power supply cable 91 and the power supply port 12A.

[0078] On the other hand, if the determination in S2 is "no," that is, the detected value S is less than the first threshold T1 (T1 > S), proceed to S7. In S7, the alarm is turned off. That is, in S7, if a warning is displayed on the monitor 34, the display is stopped; if an alarm sound or warning voice is being output from the alarm 39, the output is stopped. Following S7, in S8, the output restriction of the electric motor 9 is turned off. That is, in S8, if the speed of the electric motor 9 is restricted, the restriction is lifted, and the speed returns to the speed set by the speed dial 36. If the restriction of the electric motor 9 is lifted in S8, the process proceeds to the start step via the end step and repeats the processing after S1.

[0079] As described above, the hydraulic excavator 1 of the embodiment includes a cable clamp 26 as a cable support component, a tension sensor 29 as a load detection sensor, and a controller 16 as a control device. The cable clamp 26 is provided on the upper rotating body 3 constituting the vehicle body. The cable clamp 26 supports a power cable 91 connected to a power supply port 12A. The tension sensor 29 detects a state quantity (tension) corresponding to the load applied from the power supply cable 91 to the cable clamp 26. The controller 16 issues a notification when the detected value of the tension sensor 29 (i.e., the state quantity detected by the tension sensor 29) exceeds a predetermined threshold (threshold T1, threshold T2).

[0080] Thus, according to the embodiment, the cable clamp 26 supporting the power supply cable 91 connected to the power supply port 12A of the upper rotating body 3 is provided on the upper rotating body 3 constituting the vehicle body. Therefore, the detection value of the tension sensor 29, that is, the state quantity (tension) corresponding to the load applied from the power supply cable 91 to the cable clamp 26, can be made to correspond approximately directly to the load applied to the power supply cable 91. Moreover, this correspondence hardly changes even if the operating environment changes. Therefore, regardless of the operating environment, the thresholds (threshold T1, threshold T2) used for notification, that is, the thresholds (threshold T1, threshold T2) used in the notification process to suppress damage to the power supply cable 91 and the power supply port 12A, can be set to be the same. As a result, the time required for adjusting the overload detection device (cable load detection device) of the power supply cable 91 corresponding to the operating environment can be reduced.

[0081] According to the embodiment, the cable clamp 26 is supported on the upper rotating body 3 via an arm member 23 mounted on the upper rotating body 3 as a vehicle body side support member. Furthermore, as a state quantity, the tension sensor 29 detects the change in tension corresponding to the displacement of the cable clamp 26 relative to the arm member 23. That is, the tension sensor 29 detects the change in tension corresponding to the displacement of the cable clamp 26 relative to the arm member 23 mounted on the upper rotating body 3. Therefore, based on the correspondence between the "change in tension corresponding to the displacement of the cable clamp 26" and the "load applied to the power supply cable 91," a threshold for determining whether to issue a notification can be set.

[0082] According to the embodiment, the end (front end) of the arm member 23 extends from the upper rotating body 3, and the cable clamp 26 is supported at the end (front end) of the arm member 23 in a displaceable manner. That is, the cable clamp 26 is supported at the end (front end) of the arm member 23, which is the part extending from the upper rotating body 3, in a displaceable manner. Therefore, for example, the distance between the part of the power cable 91 supported (held) by the cable clamp 26 and the power supply port 12A can be increased, and the degree of freedom in handling the power cable 91 can be improved. In addition, since the power cable 91 is supported by the part extending from the upper rotating body 3, the possibility of the power cable 91 being crushed by the lower traveling body 2 and the possibility of the power cable 91 being wound up as the upper rotating body 3 rotates can be further reduced.

[0083] According to the embodiment, a guide member (not shown) is provided between the cable clamp 26 and the arm member 23 (bracket 27) to limit the displacement direction of the cable clamp 26 relative to the arm member 23 (bracket 27). Additionally, a spring member 28, which is an elastic member, is provided between the cable clamp 26 and the arm member 23 (bracket 27) and elastically deforms with the displacement of the cable clamp 26. Therefore, the displacement direction of the cable clamp 26 can be limited, and the situation where the cable clamp 26 displaces significantly despite a small load applied to the power supply cable 91 can be suppressed. Thus, the correspondence between the "change in displacement of the cable clamp 26 relative to the arm member 23" and the "load applied to the power supply cable 91" can be obtained with high accuracy. At the same time, the situation where the controller 16 issues a notification can be suppressed even when the load applied to the power supply cable 91 is small. Therefore, unnecessary notifications from the controller 16 can be suppressed, and the accuracy of the notification can be improved.

[0084] According to the embodiment, a variable component is provided that varies according to the displacement of the cable clamp 26 relative to the arm member 23. Based on this, a tension sensor 29, which serves as a load detection sensor, detects the change in tension of the wire 30, which serves as the variable component. Therefore, based on the correspondence between the "change in tension of the wire 30" and the "load applied to the power supply cable 91", a threshold for determining whether to issue a notification can be set.

[0085] According to the embodiment, the steel wire 30, as a variable component, is fixed to both the vehicle body side (vehicle body side steel wire support 32) and the cable clamp 26 side (vehicle body side steel wire support 32). Furthermore, as a state quantity, the tension sensor 29 detects the load applied to the steel wire 30. That is, the tension sensor 29 detects the load (tension) applied to the steel wire 30 fixed to both the vehicle body side (vehicle body side steel wire support 32) and the cable clamp 26 side (vehicle body side steel wire support 32). Therefore, based on the correspondence between the "load (tension) applied to the steel wire 30" and the "load applied to the power supply cable 91," a threshold for determining whether to issue a notification can be set.

[0086] More specifically, according to the embodiment, a steel wire 30 is used as a variable component that changes according to the displacement of the cable clamp 26 relative to the arm member 23. The steel wire 30 is installed between the vehicle body side (vehicle side steel wire support 32) and the cable clamp 26 side (clamping side steel wire support 31). The tension of the steel wire 30 changes according to the displacement of the cable clamp 26. A tension sensor 29 detects the tension of the steel wire 30. Therefore, based on the correspondence between "tension of the steel wire 30" and "load applied to the power supply cable 91", a threshold for determining whether to issue a notification can be set.

[0087] According to the embodiment, the controller 16 provides notification by emitting an alarm sound from the alarm 39 and / or by displaying a warning on the screen of the monitoring device 34, which serves as a monitor. In addition, the controller 16 also provides notification by restricting the movement of the hydraulic excavator 1 (restricting the rotation of the electric motor 9). Therefore, the operator can perform necessary operations (operations to restrict movement) based on the notification from the controller 16. Furthermore, the movement of the hydraulic excavator 1 is automatically restricted based on the notification from the controller 16 (restricting the output of the electric motor 9 and even the hydraulic pump 10). This helps to prevent damage to the power supply cable 91. It should be noted that the controller 16 may also provide notification, for example, by illuminating a warning light located in the cab 6. That is, as a method of notification, the controller 16 provides an alarm sound, a warning light, a warning display on the monitor, or movement restriction.

[0088] Regardless of the implementation method, even if the operating environment changes, the positional relationship of the shaft component 22, arm component 23, cable clamp 26, spring component 28, and steel wire 30 fixed on the upper rotating body 3 remains almost unchanged. Furthermore, the controller 16 uses the detection value S of the tension sensor 29, which corresponds to the displacement of the cable clamp 26, to determine the load on the power supply cable 91. Therefore, it is not necessary to adjust the threshold values ​​T1 and T2 used to determine the load on the power supply cable 91. That is, the time required to adjust the threshold values ​​T1 and T2 according to the operating environment can be reduced, and control (action control) for protecting the power supply cable 91 can be easily performed.

[0089] It should be noted that, in this embodiment, the example given is that the variable component, which changes according to the displacement of the cable clamp 26 relative to the arm member 23, is a steel wire 30, and the load detection sensor, which detects the change (load) corresponding to the displacement of the cable clamp 26 relative to the arm member 23, is a tension sensor 29. However, this is not a limitation. For example, the variable component could be a spring member located between the arm member (vehicle side support member) and the cable clamp (cable support member), and the load detection sensor could be a load sensor, i.e., a load sensor that detects the load applied to the spring member. Alternatively, a displacement sensor that detects the length of the spring member could also be used as the load detection sensor.

[0090] In this embodiment, an example is given where a variable component (wire 30) is provided that changes according to the displacement of the cable clamp 26 relative to the arm member 23. However, this is not a limitation. For example, the embodiment may be configured without the variable component and instead use a displacement sensor as a load detection sensor to detect the displacement of the cable clamp (cable support member) relative to the arm member (vehicle side support member). Furthermore, a load sensor may be provided between the arm member (vehicle side support member) and the cable clamp (cable support member) as a load detection sensor, and the load (state quantity) applied between the arm member (vehicle side support member) and the cable clamp (cable support member) may be detected by the load sensor. The state quantity detected by the load detection sensor is only required to be a state quantity corresponding to the load applied to the cable clamp (cable support member) via the power supply cable, and is not limited to displacement or load; other state quantities may also be used.

[0091] The implementation example illustrates the following scenario: two thresholds, T1 and T2, are set. If threshold T1 is exceeded, a warning notification and a notification regarding the operation limitation of the hydraulic excavator 1 are issued. If threshold T2, which is a value greater than threshold T1, a warning notification and a notification indicating that the hydraulic excavator 1 has stopped operating are issued. However, this is not a limitation. For example, a warning notification can be issued if threshold T1 is exceeded, a notification regarding the operation limitation of the hydraulic excavator 1 can be issued if threshold T2, which is a value greater than threshold T1, and a notification indicating that the hydraulic excavator 1 has stopped operating can be issued if threshold T3, which is a value greater than threshold T2, is exceeded. Alternatively, a single threshold can be set, and a notification indicating that the hydraulic excavator 1 has stopped operating can be issued if this threshold is exceeded. The "threshold" and the "notification" when the threshold is exceeded can be set (selected) to suppress damage to the power supply cable and power port.

[0092] In this embodiment, a hydraulic excavator 1 equipped with a swing-type working device 4 is used as an example for explanation. However, it is not limited to this, and can also be applied to hydraulic excavators equipped with a single-arm working device, hydraulic excavators equipped with an offset working device, or other types of working devices (front devices). In addition, the case where the working tool of the working device 4 is set as a bucket 4D is used as an example for explanation, but working devices equipped with other working tools such as a crusher can also be used, for example.

[0093] In this embodiment, a hydraulic excavator 1 equipped with a battery storage device 11 mounted on the upper rotating body 3 is used as an example for explanation. That is, in this embodiment, an electric hydraulic excavator 1 that is driven by electricity from an external power source 92 and also by electricity charged to the battery storage device 11 is used as an example for explanation. However, it is not limited to this, for example, an electric work machine that does not have a battery storage device and is driven by electricity from an external power source only can also be used.

[0094] In this embodiment, a hydraulic excavator 1 with a cab 6 is used as an example for explanation. However, it is not limited to this; for example, a hydraulic excavator with a canopy can also be used.

[0095] In this embodiment, a small hydraulic excavator 1 is used as an example for explanation, but it can also be applied to medium and large hydraulic excavators, for example. In addition, the case in which the body is composed of a lower traveling body 2 and an upper rotating body 3 is used as an example for explanation, but it can also be a body without a rotating body (for example, an articulated body in which a front body with front wheels and a rear body with rear wheels are connected in a flexible manner via a connecting shaft).

[0096] In the implementation, a hydraulic excavator 1 is cited as an example of a working machine, but it is not limited to this. For example, it can be widely used in various working machines such as wheel loaders, forklifts, tractors, and combine harvesters.

[0097] Explanation of reference numerals in the attached figures

[0098] 1. Electric hydraulic excavator (electric work machinery)

[0099] 2. Lower running body (vehicle body)

[0100] 3. Upper rotating body (vehicle body)

[0101] 4. Operating device

[0102] 9. Electric motor (power source)

[0103] 12A power supply port

[0104] 16 Controllers

[0105] 23. Arm assembly (vehicle side support assembly)

[0106] 26. Cable clamp (cable support component)

[0107] 28. Spring components (elastic components)

[0108] 29. Tension sensor (load detection sensor)

[0109] 30 Steel wire (variable component)

[0110] 34. Monitoring device (monitor)

[0111] 39. Alarm

[0112] 91 Power supply cable.

Claims

1. An electric work machine, comprising a mobile body and a work device mounted on said body, The vehicle body is equipped with a power supply port for connecting a power cable to the power source. The electric work machinery is characterized by having: A shaft component, which is mounted on the vehicle body with its axis extending vertically along its axis; A vehicle body side support component is mounted on the shaft component in a manner that allows it to rotate about the axis center in the vertical direction of the shaft component; A locking mechanism that can fix the vehicle body side support member to the shaft member at multiple positions in the rotational direction; A cable support component is displaceably disposed on the vehicle side support component and holds the power supply cable connected to the power supply port; A guiding component, disposed between the cable support component and the vehicle body side support component, restricts the displacement of the cable support component relative to the vehicle body side support component to a linear displacement in the horizontal direction; A load detection sensor that detects the amount of change corresponding to the displacement of the cable support member relative to the vehicle body side support member; and The controller notifies the system when the load detection sensor's value exceeds a predetermined threshold. The locking mechanism secures the vehicle body side support component at the following positions: the cable holding position where the end of the vehicle body side support component extends from the vehicle body. The cable support member is supported at the end of the vehicle body side support member via the guide member in a manner that allows displacement only in the horizontal direction.

2. The electric operating machinery according to claim 1, characterized in that, The vehicle body has a cab, which is formed in a box shape by being surrounded by a front surface, a rear surface, a left side surface, a right side surface, and a top surface. The locking mechanism secures the vehicle side support member in two positions: a cab-side receiving position where the vehicle side support member is positioned along the right side of the cab, and a cab-rear receiving position where the vehicle side support member is positioned along the rear surface of the cab.

3. The electric operating machinery according to claim 1, characterized in that, It includes a variable component that adapts to the displacement of the cable support member relative to the vehicle body side support member. The variable component is fixed to both the vehicle body side and the cable support component side. As the change, the load detection sensor detects the load applied to the changing component.

4. The electric operating machinery according to claim 1, characterized in that, It includes a variable component that adapts to the displacement of the cable support member relative to the vehicle body side support member. The variable component is a steel wire that is laid between the vehicle body side and the cable support component side. As the change, the load detection sensor detects the tension of the steel wire.

5. The electric operating machinery according to claim 1, characterized in that, The vehicle body has a self-propelled lower driving body and an upper rotating body rotatably mounted on the lower driving body. A counterweight is installed on the rear side of the rotating frame of the upper rotating body. The cable holding position is the position where the end of the vehicle body side support component extends from the rear surface of the counterweight.

Images