JP3070284U - Sub-boom load detector for aerial work vehicles - Google Patents

Abstract

(57) Abstract: A vertical lifting load when a sub-boom is used for a winch and a horizontal horizontal pulling load when a sub-boom is used for a temporary support are selectively detected. SOLUTION: Based on the up-and-down angle of the sub-boom 50 detected by an up-and-down angle detector 91, it is determined whether the sub-boom 50 is in a lifting work posture or a temporary support work posture. Here, when it is determined that the sub-boom 50 is in the lifting work posture, the up-down angle of the sub-boom 50 detected by the up-down angle detector 91, the length of the sub-boom 50 detected by the length detector 92, and the load detector Sub-boom hoist cylinder 72 detected by 93
The vertical load acting on the distal end of the sub-boom 50 is calculated based on the load of the sub-boom 50, and when it is determined that the sub-boom 50 is in the temporary support work posture, the vertical load is determined based on the length of the sub-boom 50 and the load of the sub-boom hoist cylinder 72 The horizontal load acting on the tip of the sub-boom 50 is calculated.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a sub-boom load detecting device capable of detecting a load acting on a sub-boom provided in a high-altitude work vehicle.

[0002]

[Prior art]

 Conventionally, there is known an aerial work vehicle capable of moving a workbench by a main boom provided on a vehicle body, but some of such aerial work vehicles are capable of raising and lowering at the tip of the main boom. In some cases, a sub-boom is attached and used as a winch boom or as a temporary support for pushing up and supporting an electric wire upward.

[0003] When the sub-boom is used for temporary support, a horizontal pulling load from the electric wire is applied to the front end of the sub-boom. If the horizontal pulling load becomes excessive, the overturning moment increases. As a result, the vehicle body may become unstable or the sub boom may be damaged. For this reason, the aerial work vehicle for temporary support work is provided with a load detecting device capable of detecting such a lateral pulling load, thereby preventing the vehicle body from tipping over.

When a sub-boom is used for a winch, a vertical lifting load acts on the front end of the sub-boom. There is a possibility that an excessive load may act on the device, resulting in breakage. For this reason, a restricting device is incorporated in the hydraulic circuit for driving the winch in advance, so that anything exceeding the specified weight cannot be lifted. As such a regulating device, for example, there is a device in which a lifting load is detected as a pressure in a hydraulic circuit, and the hydraulic oil is relieved when the pressure exceeds a predetermined pressure.

[0005]

[Problems to be solved by the present invention] However, even in the case of an aerial work vehicle in which a restricting device for restricting the lifting is incorporated, a heavy object is lifted by raising the main boom, not by a winch. In such a case, the above-described regulation does not work, and an excessive load may act on the sub-boom. Here, even if a restricting device that prohibits the operation of the main boom that causes an excessively large overturning moment of the vehicle body is incorporated, if the lifting position is sufficiently close to the center of the vehicle body, Such restrictions do not work because the can be raised freely. Further, since the direction of the load acting on the tip of the sub-boom is different, the above-described load detecting device for detecting the lateral pulling load cannot be used as it is for the lifting load detection.

[0006] The present invention has been made in view of such a problem, and a vertical lifting load when a sub-boom is used for a winch and a horizontal horizontal pulling load when a sub-boom is used for a temporary support. It is an object of the present invention to provide a sub-boom load detection device for an aerial work vehicle capable of selectively detecting a load.

[0007]

[Means for Solving the Problems]

 In order to achieve such an object, the safety device for an aerial work vehicle according to the present invention includes an aerial work vehicle capable of moving a workbench by a main boom provided on a vehicle body, and a leading end portion of the main boom. A sub-boom provided to be able to swing up and down, an actuator for raising and lowering the sub-boom (for example, the sub-boom raising and lowering cylinder 72 in the embodiment), a raising and lowering angle detector for detecting a raising and lowering angle of the sub-boom, and detecting a length of the sub-boom Based on the length detector, the load detector that detects the load on the actuator, and the elevation angle of the sub-boom detected by the elevation angle detector, it is determined whether the sub-boom is in the lifting work posture or the temporary support work posture. The judgment unit (for example, the controller 90 in the embodiment) for making the judgment and the sub-boom are set in the lifting posture by the judgment unit. Is determined based on the sub-boom undulation angle detected by the undulation angle detector, the sub-boom length detected by the length detector, and the actuator load detected by the load detector. The vertical load acting on the sub-boom is calculated and when the sub-boom is judged to be in the temporary support work posture, the length of the sub-boom detected by the length detector and the actuator load detected by the load detector are determined. A computing unit (for example, the controller 90 in the embodiment) for calculating a horizontal load applied to the tip of the sub-boom based on the load.

In the sub-boom load detecting device having such a configuration, first, it is determined whether the sub-boom is in the lifting work posture or the temporary supporting work posture, and here it is determined that the sub-boom is in the lifting work posture. The vertical load acting on the tip of the sub-boom is calculated from the angle of the sub-boom, the length of the sub-boom, and the load on the actuator, and when it is determined that the sub-boom is in the temporary support working posture, The horizontal load acting on the tip of the sub-boom is calculated from the length of the sub-boom and the load on the actuator.

Since the sub-boom load detecting device according to the present invention has such a configuration, a vertical lifting load when the sub-boom is used for a winch and a horizontal lifting load when the sub-boom is used for a temporary support are used. It is possible to selectively detect both loads in different directions of action, that is, lateral pulling loads, depending on the usage of the sub-boom. Here, since the direction of action of the load accompanying the use of the sub-boom is automatically identified, there is no need for the operator to perform the switching operation, so that the workability is excellent and the accidental trouble due to the switching error is prevented.

[0010] Here, when it is determined by the determiner that the sub-boom is in the lifting work posture, the vertical load calculated by the calculator is compared with a predetermined allowable vertical load, and the vertical load is calculated. Outputs a warning signal when the load exceeds the allowable load in the vertical direction, and when the judgment unit judges that the sub-boom is in the temporary support working posture, the horizontal load calculated by the arithmetic unit is calculated in the horizontal direction. The comparator (for example, the controller 90 in the embodiment) that outputs an alarm signal when the horizontal load exceeds the allowable load in the horizontal direction, as compared with the allowable load, and receives the alarm signal from the comparator. It is preferable to have a configuration having an alarm unit (for example, the alarm lamp 44 and the alarm buzzer 45 in the embodiment) for performing an alarm operation.

With such a configuration, an alarm is issued when the calculated vertical load or horizontal load of the sub boom tip exceeds the allowable load in each direction, so that the sub boom is used for the winch. The sub-boom can be prevented from being damaged and the vehicle body can be overturned in both cases where it is used and when it is used for temporary support in wire construction, and high safety is maintained. In the present invention, the lifting load is calculated based on the load of the actuator that raises and lowers the sub-boom, so that it is possible to handle lifting by raising the main boom instead of lifting by a winch. is there.

[0012]

[Embodiment of the invention]

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an example of an aerial work vehicle equipped with the sub-boom load detecting device according to the present invention. The aerial work vehicle 1 includes a vehicle body 10 capable of traveling with tire wheels 11, a swivel 20 provided on the vehicle 10, and a swing pin 20 which is swingable on a top of the swivel 20 by a foot pin 21. The main boom 30 includes a main boom 30, a workbench 40 mounted at a tip of the main boom 30, and a sub boom 50 provided at a tip of the main boom 30.

A jack 12 operated by hydraulic pressure is provided at four lateral sides of the vehicle body 10, and can be extended downward to lift and support the vehicle body 10. The swivel base 20 is attached to the vehicle body 10 so as to be freely rotatable around a vertical axis by 360 degrees, and can be swiveled in a horizontal plane by hydraulically operating a main boom swing motor 13 built in the vehicle body 10. Is possible. The main boom 30 is assembled in a telescoping manner, and can be extended and contracted in the longitudinal direction by hydraulically operating a built-in main boom telescopic cylinder 31, and is provided between the swivel 20. By operating the main boom hoist cylinder 22 hydraulically, the main boom hoist cylinder 22 can be hoisted in the upper and lower surfaces including the central axis of the boom 30.

The workbench 40 is rotatably mounted on a vertical post 32 mounted on the tip of the main boom 30, and the built-in workbench swing motor 41 is hydraulically actuated to rotate the workbench 40 around the vertical post 32. It is possible to swing the head. The vertical post 32 is always kept vertical by a leveling device (not shown), so that the floor surface of the work table 40 is always kept horizontal.

As shown in FIG. 3, a sub-boom turning member 51 is attached to the upper part of the vertical post 32 so as to be rotatable around the vertical axis by 360 degrees, and a sub-boom turning motor 71 built in the vertical post 32 is operated. By hydraulically operating, it is possible to perform turning operation in the horizontal plane. A sub-boom mounting bracket 52 is swingably attached to the sub-boom turning member 51, and can be raised and lowered in the upper and lower surfaces by hydraulic operation of a sub-boom raising / lowering cylinder 72 provided between the sub-boom turning member 51. It is possible. The sub-boom 50 is attached to the sub-boom mounting bracket 52 so as to be slidable in the longitudinal direction, and one of a plurality of pin holes 53 provided on the side surface of the sub-boom 50 is attached to the sub-boom mounting bracket 52. By inserting the fixing pin 54 in a state where the pin is aligned with the formed pin hole (not shown), the sub-boom 50 can be fixed to the sub-boom mounting bracket 52 with the length thereof being adjusted as desired.

A winch 55 is provided on the sub-boom mounting bracket 52, and the winch 55 can be driven to rotate by hydraulic operation of a winch drive motor 73. A rope 56 wound up and fed by a winch 55 is hung over a sheave 58 that is supported by a rotation itself on a sheave bracket 57 that can be detachably attached to the tip of the sub-boom 50, and hangs down from the sheave 58. A hook 59 for suspension is attached to the tip of the rope 56.

As shown in FIG. 1, the hydraulic operation of the main boom raising / lowering cylinder 22, the main boom telescopic cylinder 31, the main boom swing motor 13, and the worktable swing motor 41 is performed by a hydraulic pump P provided in the vehicle body 10. The supply of the supplied hydraulic oil is controlled by supplying the hydraulic oil to the hydraulic cylinders and the motors. The operation is performed by driving the hydraulic valves V1, V2, V3 and V4 via the controller 90 by operating the worktable swing operation lever L2. Therefore, the operator can move the main boom 30 up and down, extend and retract, turn, and swing the work table 40 to a desired position by operating the lever.

The hydraulic operation of the sub-boom raising / lowering cylinder 72, the sub-boom swing motor 71, and the winch drive motor 73 is also performed by controlling the supply of hydraulic oil supplied from the hydraulic pump P. The hydraulic oil is supplied to the control box 42 by operating the sub-boom operation lever L3 and the winch operation lever L4 provided on the operation box 42 to drive the hydraulic valves V5, V6 and V7 via the controller 90. Therefore, the operator can position the sub-boom 50 at the desired turning angle and the up-and-down angle by operating the sub-boom operation lever L3, and rotate the winch 55 in the desired direction by operating the winch operation lever L4. Then, it is possible to lift a heavy object.

The sub-boom 50 can also be used for temporary support in electric wire construction. In this case, as shown in FIG. 4, the sheave bracket 57 is detached from the distal end of the sub-boom 50, the temporary support device 80 is attached, the hook 59 is hooked on the hook metal fitting 60 below the sub-boom 50, and the sub-boom 50 Then, the fixing pin 54 for fastening the sub-boom mounting bracket 51 is removed so that the sub-boom 50 is slidable, and the sub-boom 50 is raised and held in a vertical state (a state in which the undulation angle is 90 degrees). Then, the electric wire D (shown in cross section in FIG. 4) is held by the electric wire holder 81 of the temporary support device 80 as shown in the figure, the winch 55 is driven to wind the rope 56, and the sub boom 50 is slid upward. By doing so, it is possible to push up the electric wire D upward while the work table 40 is fixed.

The sub-boom 50 can be used for a winch or a temporary support as described above. In the present invention, in these cases, the load acting on the tip of the sub-boom 50 is larger than the allowable load. In order to prevent a situation in which the sub boom 50 is damaged and the vehicle body 10 falls over, the following load detecting device is provided. Hereinafter, this device will be described.

As shown in FIG. 3, the sub-boom 50 detects the undulation angle of the sub-boom 50 (for example, the angle formed by the center axis of the sub-boom 50 and the horizontal plane, which is indicated by θ in FIG. 3). 91 and a length detector 92 for detecting the length of the sub-boom 50 (for example, the distance between the fixing pin 54 and the center of the sheave 58; this is indicated by L in FIG. 3). A load detector 93 is provided in the sub-boom hoist cylinder 72 to detect the load of the sub-boom hoist cylinder 72 as pressure on the bottom side (or on the rod side). Here, the length detector 92 is configured to detect the length of the sub-boom 50 by taking up and feeding out a wire 92a extending from the lower part of the sub-boom 50 and detecting the amount thereof. Another configuration may be used as long as the length can be detected.

In the storage unit of the controller 90, whether the current sub-boom 50 is used for a winch based on the up-and-down angle of the sub-boom 50 detected by the up-and-down angle detector 91 (that is, the Is stored, or data for determining whether it is used for temporary support (that is, whether it is in a temporary support work posture). FIG. 5 shows an example of this data. The undulation angle θ of the sub-boom 50 detected by the undulation angle detector 91 is θ ≦ θ ₁ (θ ₁ is the upper limit suitable for using the sub-boom 50 for a winch). If the angle is, for example, θ ₁ = 45 degrees, it is recognized that the sub-boom 50 is in the lifting work posture, and the undulation angle θ of the sub-boom 50 is θ ≧ θ ₂ (θ ₂ satisfies θ ₁ ≦ θ ₂₎ . The angle is approximately 90 degrees, but is preferably 90 degrees or less. For example, in the case of θ ₂ = 87 degrees, the sub boom 50 is recognized as being in the temporary support working posture. .

Here, when the controller 90 determines that the current sub-boom 50 is in the lifting work posture based on the up-down angle of the sub-boom 50 detected by the up-down angle detector 91, the controller 90 uses the up-down angle detector 91. At the tip of the sub-boom 50, based on the detected angle of the sub-boom 50, the length of the sub-boom 50 detected by the length detector 92, and the load of the sub-boom up / down cylinder 72 detected by the load detector 93. The acting vertical load W is calculated, and its value is displayed on a load indicator 43 provided on the operation box 42 (the vertical load W corresponds to the lifting load by the winch 55).

The controller 90 displays the calculated value of the vertical load W on the load display 43 as described above, and compares the vertical load W with a predetermined allowable load in the vertical direction. When the vertical load W exceeds the allowable load in the vertical direction, an alarm signal is output to turn on an alarm lamp 44 provided on the operation box 42 and to generate a buzzer sound from an alarm buzzer 45. Further, the operation of the hydraulic valve V7 is regulated to prohibit the rotation of the rope 56 of the winch drive motor 73 in the lifting direction. Thus, when the sub-boom 50 is used for a winch (lifting work), there is no risk of lifting an object having a weight larger than the allowable lifting weight, and the sub-boom 50 is not damaged and the vehicle body is not damaged. 10 falls are prevented beforehand. In the present invention, the lifting load is calculated based on the load of the actuator (the sub-boom raising / lowering cylinder 72) that raises and lowers the sub-boom 50. Therefore, the lifting is performed by raising the main boom 30 instead of raising the winch 55. In this case, the operation of the main boom 30 is regulated so that an excessive load is not applied to the sub-boom 50.

On the other hand, if the controller 90 determines that the current sub-boom 50 is in the temporary supporting work posture based on the up-and-down angle of the sub-boom 50 detected by the up-and-down angle detector 91, the length detector 92 The horizontal load F acting on the distal end of the sub-boom 50 is calculated from the length of the sub-boom 50 detected by the sub-boom 50 and the load of the sub-boom hoisting cylinder 72 detected by the load detector 93 (the load detector 93 detects the sub-boom). Since the load on the undulating cylinder 72 is detected as the pressure on the bottom side or the rod side, the direction of the load can also be detected.) The value is displayed on the load indicator 43 (the horizontal load F is (Corresponds to the lateral pull load received from the wire D). At the same time, the horizontal load F is compared with a predetermined allowable load in the horizontal direction. When the horizontal load F exceeds the allowable load in the horizontal direction, an alarm signal is output and the alarm lamp 44 is output. Is turned on, and a buzzer sound is generated from the alarm buzzer 45. In this case, in order not to further increase the lateral pulling load received from the electric wire D, the operation of the hydraulic valves V1 to V3 is regulated, and the boom 30 is moved in a direction in which the lateral pulling load from the electric wire D is increased. Is preferably prohibited. Accordingly, when the work using the sub-boom 50 for temporary support (temporary support work) is performed, there is no possibility that the lateral pulling load from the electric wire D becomes excessive, and the sub-boom 50 is not damaged and the vehicle body 10 is not damaged. Is prevented from falling down.

Since the sub-boom load detecting device according to the present invention has such a configuration, the vertical lifting load when the sub-boom 50 is used for a winch and the vertical lifting load when the sub-boom 50 is used for a temporary support are used. Both loads having different acting directions, that is, horizontal pulling loads, can be selectively detected in accordance with the use condition of the sub-boom 50. Here, the direction of action of the load associated with the usage of the sub-boom 50 is automatically identified, so that there is no need for the operator to perform the switching operation, so that the workability is excellent and the accidental trouble due to the switching error is prevented. You.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above. For example, the actuator for raising and lowering the sub-boom 50 is a hydraulic cylinder (the sub-boom raising and lowering cylinder 72) in the above embodiment, but this is not necessarily a hydraulic cylinder, and may be a hydraulic motor or an electrically driven electric actuator (for example, It may be a DC servo motor). In this case, the load detector that detects the load of the actuator has a configuration that detects the pressure in the oil passage connected to the hydraulic motor, or detects the electric power or the like of the electric actuator. Further, in the above embodiment, the length of the sub-boom 50 can be adjusted only at a position where the plurality of pin holes 53 provided on the side surface of the sub-boom 50, and the length cannot be continuously adjusted. Alternatively, the length of the sub-boom 50 may be continuously changed by using a hydraulic cylinder or the like that can be extended and contracted in the length direction of the sub-boom 50.

Further, based on the elevation angle of the sub-boom 50 detected by the elevation angle detector 91 stored in the controller 90, it is determined whether the current sub-boom 50 is in the lifting work posture or the temporary support work posture. Since the data for determination is θ ₁ <θ ₂ in the above embodiment, the range of the undulation angle θ (θ ₁ <θ <θ ₂₎ in which the sub-boom 50 is neither the working posture nor the temporary support working posture is set. ), But it is possible to eliminate the range that is neither the lifting work posture nor the temporary support work posture by setting θ ₁ = θ ₂ .

[0029]

[Effect of the invention]

 As described above, in the sub-boom load detecting device according to the present invention, first, it is determined whether the sub-boom is in the lifting work posture or the temporary supporting work posture, and here it is determined that the sub-boom is in the lifting work posture. The vertical load acting on the tip of the sub-boom is calculated from the sub-boom undulation angle, the sub-boom length, and the actuator load when the sub-boom is in the temporary support working posture. The horizontal load acting on the tip of the sub-boom is calculated from the load of the sub-boom, so the vertical lifting load when the sub-boom is used for the winch and the vertical lifting load when the sub-boom is used for temporary support are used. Loads in different directions of action called horizontal pulling loads It can be selectively detected according to the usage status of Bubumu. Here, the direction of action of the load associated with the use of these sub-booms is automatically identified, so there is no need for the operator to perform the switching operation, so that the workability is excellent and accidental switching due to switching mistakes is prevented. .

An alarm is issued when the calculated vertical load or horizontal load at the tip of the sub-boom exceeds the allowable load in each direction. Therefore, when the sub-boom is used for a winch and in wire construction, Corresponding to either case of temporary use, damage to the sub-boom and tipping of the vehicle body can be prevented beforehand, and high safety is maintained. In addition, in the present invention, the lifting load is calculated based on the load of the actuator that raises and lowers the sub boom, so that the lifting can be performed by raising the main boom rather than by a winch. .

[Submission date] March 9, 2000 (200.3.9)

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

[Means for Solving the Problems]

In order to achieve such an object, a sub-boom load detection device for an aerial work vehicle according to the present invention includes an aerial work vehicle capable of moving a workbench by a main boom provided on a vehicle body, and a main boom. A sub-boom provided at the tip of the sub-boom so as to be able to swing up and down, an actuator for raising and lowering the sub-boom (for example, the sub-boom raising and lowering cylinder 72 in the embodiment), a raising and lowering angle detector for detecting the sub-boom raising and lowering angle, A length detector for detecting the height of the sub-boom, a load detector for detecting the load on the actuator, and a first predetermined angle at which the elevation angle of the sub-boom detected by the elevation angle detector corresponds to a predetermined lifting posture of the sub-boom. range (e.g., within the angle range of theta ≦ theta ₁ in the embodiment) first determining means for determining whether or not the (eg example, embodiments Definitive controller 90), the undulations in the second predetermined angular range angle detector derricking angle of Sabubumu detected by corresponding to the temporary support Ergonomics Sabubumu a predetermined (e.g., an angle range of theta ≧ theta ₂ in the embodiment And the second determining means (for example, the controller 90 in the embodiment) for determining whether or not the sub-boom angle is within the first predetermined angle range by the first determining means. The vertical direction acting on the tip of the sub-boom based on the sub-boom undulation angle detected by the undulation angle detector, the length of the sub-boom detected by the length detector, and the load on the actuator detected by the load detector The first calculating means for calculating the load (for example, the controller 90 in the embodiment) and the second judging means make the sub boom undulate. When it is determined that the degree is within the second predetermined angle range, it acts on the tip of the sub-boom based on the length of the sub-boom detected by the length detector and the load of the actuator detected by the load detector. And a second calculating means (for example, the controller 90 in the embodiment) for calculating a horizontal load to be applied.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Here, the vertical load calculated by the first calculating means is compared with a predetermined allowable load in the vertical direction, and when the vertical load exceeds the allowable load in the vertical direction, a first alarm signal is issued. Is compared with the horizontal load calculated by the second calculating means and a predetermined allowable load in the horizontal direction, and the horizontal load is calculated by the first comparing means (for example, the controller 90 in the embodiment). A second comparing means (for example, the controller 90 in the embodiment) for outputting a second alarm signal when the load exceeds a horizontal allowable load, and the first alarm signal or the second ratio output from the first comparator. Alarm means (for example, an alarm lamp 44 or an alarm buzzer 45 in the embodiment) for performing an alarm operation in response to the second alarm signal output from the comparator. Is preferred.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a sub-boom load detecting device according to the present invention.

FIG. 2 is a side view of an aerial work vehicle equipped with the sub-boom load detecting device.

FIG. 3 is a diagram showing a case where a sub-boom in the aerial work vehicle is used for a winch.

FIG. 4 is a diagram showing a case where a sub-boom in the aerial work vehicle is used for temporary support.

FIG. 5 is a diagram showing an example of data for determining whether the current sub-boom is in a lifting work posture or in a temporary support work posture, based on a sub-boom up / down angle stored in a controller.

[Explanation of symbols]

 Reference Signs List 1 aerial work vehicle 10 body 30 main boom 40 work bench 44 alarm lamp (alarm means) 45 alarm buzzer (alarm means) 50 sub-boom 72 sub-boom up / down cylinder (actuator) 90 controller (judgment unit, arithmetic unit, comparator) 91 up / down Angle detector 92 Length detector 93 Load detector

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 9, 2000 (200.3.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims for utility model registration

[Correction method] Change

[Correction contents]

[Utility model registration claims]

Continued on the front page (72) Inventor Yoshito Nohara 41-1 Higashimine Sugawa, Shinji-mura, Tone-gun, Gunma Prefecture Aichi Corporation Shinji Factory

Claims (2)

[Utility model registration claims] 1. An aerial work vehicle capable of moving a workbench by a main boom provided on a vehicle body, a sub-boom provided at a tip end of the main boom so as to be swingable up and down, and raising and lowering the sub-boom An actuator to be moved, an up-and-down angle detector that detects an up-down angle of the sub-boom, a length detector that detects the length of the sub-boom, a load detector that detects a load of the actuator, and the up-down angle detector A judging device for judging whether the sub-boom is in the lifting work posture or the temporary supporting work posture based on the detected undulation angle of the sub-boom, and judging that the sub-boom is in the lifting work posture by the judging device. The sub-boom undulation angle detected by the undulation angle detector, detected by the length detector The vertical load acting on the tip of the sub-boom is calculated based on the length of the sub-boom and the load on the actuator detected by the load detector, and the sub-boom is set to the temporary support working posture by the determiner. When it is determined that there is, a horizontal load acting on the tip of the sub-boom is calculated based on the length of the sub-boom detected by the length detector and the load on the actuator detected by the load detector. A sub-boom load detection device for an aerial work vehicle, comprising: 2. When the sub-boom is determined to be in the lifting work posture by the determiner, the vertical load calculated by the calculator is compared with a predetermined allowable vertical load, and A warning signal is output when the vertical load exceeds the allowable load in the vertical direction, and when the sub-boom is determined to be in the temporary supporting work posture by the determiner, the horizontal calculated by the calculator is calculated. Comparing the directional load with a predetermined allowable load in the horizontal direction, a comparator that outputs an alarm signal when the horizontal load exceeds the allowable load in the horizontal direction, and the alarm signal from the comparator. The sub-boom load detecting device for an aerial work vehicle according to claim 1, further comprising alarm means for receiving and performing an alarm operation.