Aerial work platform

Abstract

To provide a vehicle for high lift work capable of operating a hydraulic actuator provided at a tip part of a boom from a lower operation device without increasing a cross-sectional area of the boom by adding a new conduit.SOLUTION: A lower controller 12 that controls operations of a plurality of hydraulic actuators based on an operation signal from a lower operating device 11, an oscillating motor 17, a winching motor 23a, a working hydraulic cylinder 35, and a retracting hydraulic cylinder 36 that are operated by hydraulic fluid discharged from a hydraulic pump 51, and a first drain oil passage 23a for returning hydraulic fluid leaked from the oscillating motor 17 and the winching motor LD1 to a hydraulic fluid tank 50, the hydraulic cylinders 36 for storage are operated by switching the upper operation switching valve 55 so that the hydraulic fluid discharged from the hydraulic pumps 51 according to the operation of the lower operation device 11 flows to the first drain oil passage LD1.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a vehicle for working at height that is provided with a work platform at the tip of a boom provided on a vehicle body. [Background technology]

[0002] In a vehicle for aerial work that includes a platform at the tip of the boom and a winch device with a sub-boom, when the vehicle travels on public roads with the sub-boom attached to the winch device, the sub-boom may cause interference when passing through tunnels or under elevated roads. To address this issue, conventional methods have been devised to minimize the vehicle height when the sub-boom and winch device are stowed. For example, in the vehicle for aerial work described in Patent Document 1, when the sub-boom device is stowed, the hoisting member is first activated to raise the sub-boom support member diagonally upward together with the sub-boom member. Next, the sub-boom member is slid rearward relative to the sub-boom support member, which is tilted diagonally upward, and the sub-boom member is secured to the sub-boom support member at a position where the tip of the sub-boom member is adjacent to the sub-boom support member. This causes the base end of the sub-boom member to protrude diagonally downward from the sub-boom support member. In this state, the sub-boom support member is slid rearward relative to the hoisting member and secured with a pin, thereby further moving the sub-boom support member and the sub-boom member diagonally downward. By configuring it in this way, the winch device can be stored at a position lower than the height of the work platform when the sub-boom is attached.

[0003] The aerial work platform described in Patent Document 2 has a work platform attached to the tip of the boom, and the work platform is equipped with an upper control device operated with levers or the like, an upper control device that receives operation signals from the upper control device and controls the operation of the boom, lifting device, etc., a battery for operating the upper control device, etc., and an upper hydraulic control valve that controls the actuators of the lifting device and work platform. Meanwhile, the vehicle body is equipped with a lower control device that receives operation signals from the lower control device and controls the operation of the boom, jack, etc., and a lower hydraulic control valve that controls the actuator that operates the boom via the lower control device. Furthermore, in an aerial work platform that electrically insulates the work platform from the vehicle body to prevent workers on the work platform from getting electric shock or damaging the vehicle when performing electrical installation work, the upper control device and lower control device are connected by optical cable, and signals transmitted and received between them are converted into optical signals at the front and rear of the boom, enabling optical communication at the boom section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-280916 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-326800 Summary of the Invention [Problem to be solved by the invention]

[0005] In the aerial work platform described in Patent Document 1, when viewed from the side, the base end of the sub-boom member overlaps with the side of the boom. Therefore, when attempting to swing the platform with the winch device stored, the sub-boom member and the boom interfere with each other. Therefore, when attempting to move the platform closer to the ground to load materials to be used in the work onto the platform, there is a risk of the sub-boom member and the boom interfering with each other. Therefore, it is necessary to move the winch device from its stored state to a position where the sub-boom member and the boom do not interfere with each other. However, with the aerial work platform described in Patent Document 1, the worker must go to the trouble of getting onto the platform to move the winch device from its stored state, which increases the worker's burden and makes the work of loading materials more complicated.

[0006] Therefore, in order to enable the operation of moving the winch device in a stored state to a position where the sub-boom member and the boom do not interfere with each other to be performed from the ground, it is conceivable to add a hydraulic actuator for sliding the sub-boom member or the winch device, and to configure the added hydraulic actuator so that it can be controlled from a lower operating device mounted on the body of the aerial work vehicle. In this case, it is also necessary to provide a control valve for controlling the hydraulic pressure supplied to the added hydraulic actuator and an upper controller that controls this control valve in response to operation of the lower operating device.

[0007] To achieve the above-described configuration, it is necessary to install an additional hose inside the boom for supplying hydraulic pressure from the vehicle body to the added hydraulic actuator, which poses the problem of requiring a larger cross-sectional area of ​​the boom. Furthermore, in the aerial work platform described in Patent Document 2, when a control signal for controlling the added hydraulic actuator is sent from the lower control device to the upper control device, the optical signal received by the upper control device must be converted into an electrical signal, which requires the power switch of the upper control device to be turned on. Therefore, the worker must get on the work platform to turn on the power switch of the upper control device, making it difficult to reduce the burden on the worker and improve the efficiency of material loading work.

[0008] The present invention has been made in consideration of these problems, and aims to provide an aerial work vehicle that allows the hydraulic actuator provided at the tip of the boom to be operated from the lower operating device without adding a new pipeline and increasing the cross-sectional area of ​​the boom. [Means for solving the problem]

[0009] In order to solve the above problems, the first aspect of the present invention provides a vehicle for working at height comprising a vehicle body, a hydraulic oil tank provided on the vehicle body for storing hydraulic oil, a hydraulic pump that applies pressure to the hydraulic oil stored in the hydraulic oil tank and discharges it, a plurality of lower hydraulic actuators provided on the vehicle body and operated by hydraulic pressure (for example, the jack cylinder 5, the swing motor 7, the derricking cylinder 9, and the telescopic cylinder 10 in the embodiment), a lower operating device provided on the vehicle body, and a control unit for controlling the hydraulic oil discharged from the hydraulic pump in response to an operation performed on the lower operating device. a lower hydraulic oil control device (for example, the lower controller 12, the jack operation valve 52, and the boom operation valve 53 in the embodiments) that controls the amount and direction of supply of hydraulic oil to the hydraulic actuators; a boom that is provided on the vehicle body so as to be able to raise and lower at least; a work platform provided at the tip of the boom; a plurality of upper hydraulic actuators that are provided at the tip of the boom and are operated by hydraulic pressure (for example, the swing motor 17, the winch motor 23a, the working hydraulic cylinder 35, and the storage hydraulic cylinder 36 in the embodiments); an upper operation device provided on the work platform; an upper hydraulic oil control device (for example, the upper operation valve 110 in the embodiments) that controls the amount and direction of supply of hydraulic oil discharged from the hydraulic pump to the plurality of upper hydraulic actuators in accordance with operations performed on the upper operation device; and a drain pipe line (for example, the first drain oil line L in the embodiments) that is disposed through the inside of the boom and that returns hydraulic oil leaked from a predetermined upper hydraulic actuator (for example, the swing motor 17 and the winch motor 23a in the embodiments) among the plurality of upper hydraulic actuators to the hydraulic oil tank. D1), a check valve (e.g., a third check valve 65 in the embodiment) that is provided in a line connecting a specific upper hydraulic actuator (e.g., the storage hydraulic cylinder 36 in the embodiment) among the plurality of upper hydraulic actuators to the drain line, and that blocks the flow of hydraulic oil from the specific upper hydraulic actuator to the drain line, and a switching valve (e.g., an upper operation switching valve 55 in the embodiment) that is provided in the drain line, and that switches whether or not the hydraulic oil discharged from the hydraulic pump is allowed to flow to the drain line, and the lower hydraulic oil control device comprises:The switching valve is switched in response to an operation performed on the lower operating device so that the hydraulic oil discharged from the hydraulic pump flows to the drain line, and the specific upper hydraulic actuator is operated by being supplied with the hydraulic oil discharged from the hydraulic pump via the drain line.

[0010] Furthermore, in the aerial work vehicle having the configuration of the first aspect described above, it is preferable that a sub-boom device having a sub-boom member and a hoisting device supporting the sub-boom member so that it can be raised or lowered is provided at the tip of the boom, the specific upper hydraulic actuator raises or lowers the hoisting device, the sub-boom device is placed in a stowed state by rotating the sub-boom member beyond the vertical position in a direction opposite to the direction in which it would be lowered during work, and when hydraulic oil discharged from the hydraulic pump is supplied via the drain line when the sub-boom device is in the stowed state, the specific upper hydraulic actuator rotates the sub-boom member in a direction in which the sub-boom member takes the vertical position.

[0011] Furthermore, in an aerial work vehicle configured as in the first aspect above, it is preferable that a drain check valve (for example, first check valve 61 and second check valve 62 in the embodiment) is provided in a pipeline connecting the specified upper hydraulic actuator and the drain pipeline to prevent the flow of hydraulic oil from the drain pipeline to the specified upper hydraulic actuator, and that the check valve is configured not to be released by the hydraulic pressure of hydraulic oil leaked from the specified upper hydraulic actuator, but to be released by the hydraulic pressure of hydraulic oil discharged from the hydraulic pump.

[0012] Furthermore, in the aerial work vehicle having the configuration of the first aspect described above, it is preferable that a branch line (e.g., a fifth pump oil line LP5 in the embodiments) branch off from a line for supplying hydraulic oil discharged from the hydraulic pump to a specific lower hydraulic actuator (e.g., the telescopic cylinder 10 in the embodiments) among the plurality of lower hydraulic actuators and be connected to the switching valve, and when the branch line is connected to the drain line by the switching valve, the lower operating device operates the operation of the specific lower hydraulic actuator, thereby supplying hydraulic oil via the drain line to operate the specific upper hydraulic actuator.

[0013] Furthermore, a second aspect of the present invention provides a vehicle for working at height comprising a vehicle body, a hydraulic oil tank provided on the vehicle body for storing hydraulic oil, a hydraulic pump that applies pressure to and discharges the hydraulic oil stored in the hydraulic oil tank, a plurality of lower hydraulic actuators provided on the vehicle body and operated by hydraulic pressure (for example, the jack cylinder 5, the swing motor 7, the derricking cylinder 9, and the telescopic cylinder 10 in the embodiment), a lower operating device provided on the vehicle body, and a control device for controlling the hydraulic oil discharged from the hydraulic pump in response to an operation performed on the lower operating device, for the plurality of lower hydraulic actuators. a lower hydraulic oil control device (for example, a lower controller 12′, a jack operation valve 52, and a boom operation valve 53 in the embodiment) that controls the amount and direction of hydraulic oil supplied to the vehicle body; a boom that is provided on the vehicle body so as to be able to raise and lower at least; a work platform provided at the tip of the boom; a plurality of upper hydraulic actuators (for example, a swing motor 17, a winch motor 23a, a working hydraulic cylinder 35, and a storing hydraulic cylinder 36 in the embodiment) that are provided at the tip of the boom and are operated by hydraulic pressure; an upper operating device provided on the work platform; an upper hydraulic oil control device (for example, an upper controller 100′ and an upper operation valve 110′ in the embodiments) that controls the supply amount and supply direction of the hydraulic oil discharged from the hydraulic pump to the plurality of upper hydraulic actuators in accordance with an operation performed on the lower operation device; a battery that supplies power to the upper hydraulic oil control device; a hydraulic switch that is provided between the upper hydraulic oil control device and the battery and is turned on by hydraulic pressure supplied from an external source; a drain pipe line (for example, a first drain oil line LD1 in the embodiments) that is provided through the inside of the boom and that returns hydraulic oil leaked from a predetermined upper hydraulic actuator (for example, a swing motor 17 and a winch motor 23a in the embodiments) among the plurality of upper hydraulic actuators to the hydraulic oil tank; and a switching valve (for example, an upper operation switching valve 55 in the embodiments) that switches whether or not the hydraulic oil discharged from the hydraulic pump is allowed to flow to the drain pipe line, and the lower hydraulic oil control device switches the switching valve in accordance with an operation performed on the lower operation device so that the hydraulic oil discharged from the hydraulic pump flows to the drain pipe line, and the hydraulic switchWhen hydraulic oil discharged from the hydraulic pump is supplied via the drain line, the switch is turned on and supplies power from the battery to the upper hydraulic oil control device.

[0014] In addition, in an aerial work vehicle configured as in the second aspect above, it is preferable to provide a drain check valve (e.g., first check valve 61 and second check valve 62 in the embodiment) that is provided in the pipeline connecting the specified upper hydraulic actuator and the drain pipeline and prevents the flow of hydraulic oil from the drain pipeline to the specified upper hydraulic actuator.

[0015] Furthermore, in an aerial work vehicle having the configuration of the second aspect described above, it is preferable to provide a branch line (for example, a fifth pump oil line LP5 in an embodiment) that branches off from a line for supplying hydraulic oil discharged from the hydraulic pump to a specific lower hydraulic actuator among the plurality of lower hydraulic actuators and is connected to the switching valve, and when the branch line is connected to the drain line by the switching valve, the operation of the specific lower hydraulic actuator is operated by the lower operating device to supply hydraulic oil via the drain line and activate the hydraulic switch. [Effects of the Invention]

[0016] According to the aerial work platform vehicle of the present invention, a plurality of upper hydraulic actuators are provided at the tip of a boom that is movably mounted on the vehicle body, and these plurality of upper hydraulic actuators are operated by hydraulic pressure supplied from a hydraulic pump. A drain line is disposed inside the boom to return hydraulic oil leaking from a specific upper hydraulic actuator to a hydraulic oil tank, and a selector valve is provided to switch whether or not hydraulic oil discharged from the hydraulic pump flows into this drain line. When the selector valve is switched so that hydraulic oil discharged from the hydraulic pump flows into the drain line in response to an operation performed on the lower operating device, the hydraulic oil discharged from the hydraulic pump is supplied via the drain line to a specific upper hydraulic actuator or a hydraulic switch, thereby operating the specific upper hydraulic actuator or hydraulic switch. This allows the specific upper hydraulic actuator at the tip of the boom to be operated from the lower operating device mounted on the vehicle body, or power to the upper hydraulic oil control device, thereby reducing the burden on the work platform and shortening the work time. Furthermore, since the drain line is used as a line for supplying hydraulic pressure to specified upper hydraulic actuators and hydraulic switches, there is no need to add a new line inside the boom, and there is no need to increase the cross-sectional area of ​​the boom.

[0017] Furthermore, in an aerial work platform having the above configuration, a sub-boom device is preferably provided at the tip of the boom, the sub-boom device including a sub-boom member and a hoisting device that raises and lowers the sub-boom member using a specific upper hydraulic actuator. The sub-boom device is stowed in a position by rotating the sub-boom member beyond the vertical position in a direction opposite to the direction in which the sub-boom member is lowered during work by the specific upper hydraulic actuator. When hydraulic oil discharged from the hydraulic pump is supplied to the specific upper hydraulic actuator through a drain line while the sub-boom device is in the stowed position, the specific upper hydraulic actuator rotates the sub-boom member in a direction in which the sub-boom member assumes a vertical position. With this configuration, an operator can move the sub-boom device from the stowed position by operating the lower operating device from the ground without boarding the work platform. This allows the boom to be operated from the ground without the sub-boom device interfering with the boom, thereby reducing the burden on the operator and shortening the work time required for loading materials onto the work platform.

[0018] Furthermore, in an aerial work vehicle having the above configuration, a drain check valve that prevents hydraulic oil from flowing from the drain line to a specific upper hydraulic actuator is preferably provided in the line connecting the specific upper hydraulic actuator and the drain line. Furthermore, if a check valve is provided between a specific upper hydraulic actuator and the drain line, the check valve is preferably configured not to be opened by the hydraulic pressure of hydraulic oil leaked from the specific upper hydraulic actuator, but by the hydraulic pressure of hydraulic oil discharged from the hydraulic pump. This allows the drain line to be used as a line that supplies hydraulic oil to a specific upper hydraulic actuator or a hydraulic switch, while maintaining its original purpose of returning hydraulic oil leaked from the hydraulic actuator to the hydraulic oil tank.

[0019] Furthermore, in an aerial work vehicle having the above configuration, preferably, a portion of the hydraulic oil supplied from the hydraulic pump to a specific lower hydraulic actuating device among the plurality of lower hydraulic actuating devices is branched off and supplied to a switching valve, and when the switching valve is switched to a path that allows the hydraulic oil supplied from the hydraulic pump to flow to the drain oil line, the operation of the specific lower hydraulic actuator is operated with the lower operating device to operate the operation of the specific upper hydraulic actuator or hydraulic switch. This allows the lower operating device for operating the operation of the specific lower hydraulic actuator to be used as an operating device for operating the operation of the specific upper hydraulic actuator or hydraulic switch, eliminating the need to add a dedicated operating device to the lower operating device and reducing manufacturing costs. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a side view showing the appearance of a vehicle for working at height according to a first embodiment of the present invention. [Figure 2] 2A and 2B are side and rear views showing the appearance of a sub-boom device provided on the aerial work vehicle. [Figure 3] FIG. 2 is an exploded view showing the configuration of the sub-boom raising and lowering device of the sub-boom device. [Figure 4] 10A to 10C are explanatory diagrams for explaining the movements of the various parts when the sub-boom device is stowed. [Figure 5] 10A to 10C are explanatory diagrams for explaining the movements of the various parts when the sub-boom device is stowed. [Figure 6] FIG. 10 is a plan view showing the positional relationship between the sub-boom member and the boom when the sub-boom device is stowed. [Figure 7] FIG. 2 is a diagram showing the configuration of the main hydraulic circuits of the aerial work vehicle and a control system for the hydraulic circuits. [Figure 8] FIG. 4 is a diagram showing the configuration of a main hydraulic circuit and a control system for the hydraulic circuit of an aerial work vehicle according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] [First embodiment] A first embodiment of the present invention will be described below with reference to the drawings. First, the overall configuration of a vehicle for high-altitude work 1 according to the present invention will be described with reference to the side view shown in FIG. 1. The vehicle for high-altitude work 1 has a truck-type vehicle body 2, equipped with tires and wheels 3 (front wheels 3f and rear wheels 3r) on the front and rear of the body 2, and can be driven from a driver's cabin 2a located at the front of the body 2. Outrigger jacks 4 that can be extended and retracted up and down are provided on the front, rear, left, and right sides of the body 2. The outrigger jacks 4 can be extended and retracted by jack cylinders 5 and outrigger cylinders (not shown). When working at height using a boom 8 (described later) or the like, the operator extends and extends each of the left and right outrigger jacks 4 in the vehicle width direction according to the relative position of the vehicle to surrounding obstacles, and extends them downward to lift and support the vehicle body 2, thereby ensuring a stable posture.

[0022] A swivel base 6 is rotatably mounted at the rear of the mounting section located behind the driver's cabin 2a, and is rotated horizontally by a swivel motor 7 mounted on the vehicle body 2. A support column 6a is mounted on the top of the swivel base 6, and the base end of a boom 8 is pivotally supported on the support column 6a by foot pins 6b so that it can be raised and lowered. The boom 8 is composed of a base boom 8a, an intermediate boom 8b, and a tip boom 8c, assembled in this order from the swivel base 6 side. A derrick cylinder 9 is mounted between the base boom 8a and the support column 6a, and the extension and retraction of the derrick cylinder 9 allows the entire boom 8 to be raised and lowered in a vertical plane. A telescopic cylinder 10 is mounted inside the boom 8, and the extension and retraction of the telescopic cylinder 10 moves the intermediate boom 8b and the tip boom 8c relative to the base boom 8a, allowing the entire boom 8 to be extended and retracted in the axial direction. Here, the boom 8 shown in FIG. 1 is in a stored state in which the telescopic cylinder 10 is fully retracted and the boom base end 8a is supported by a boom receiving portion 19 (see FIG. 6) provided on the vehicle body 2.

[0023] A lower operating device 11 is provided at the rear end of the vehicle body 2. The lower operating device 11 is equipped with operating switches for rotating the swivel base 6 and for raising and lowering / extending the boom 8, as well as an operating lever for operating the outrigger jacks 4. The lower operating device 11 is also equipped with an upper operating switch that enables operation of the storage hydraulic cylinder 36, which will be described later. A lower controller 12 is installed at the front end of the mounting section located behind the driver's cabin 2a (behind the driver's cabin 2a). The lower operating device 11 controls the supply direction and amount of hydraulic oil to hydraulic actuators such as the swing motor 7, hoisting cylinder 9, and telescopic cylinder 10, depending on the operation performed on the lower operating device 11.

[0024] A vertical post 13 is pivotally connected to the tip of the tip boom 8c so as to be swingable within the same plane as the boom 8's elevation and hoisting surface. The vertical post 13 is swing-controlled (leveling-controlled) by an upper leveling cylinder 14a mounted between the tip boom 8c and the vertical post 13 and a lower leveling cylinder 14b mounted between the base boom 8a and the support 6a so as to always extend and position vertically regardless of the elevation and hoisting of the boom 8. Note that FIG. 1 shows only the cylinder rod portion of the upper leveling cylinder 14a; the cylinder tube portion is inserted inside the tip boom 8c. A work platform bracket 15 is provided on the top of the vertical post 13, and a work platform 16 is attached to the vertical post 13 via the work platform bracket 15 so as to be swingable around the vertical post 13. By controlling the leveling of the vertical post 13 in this way, the floor surface of the work platform 16 is always kept horizontal regardless of the elevation and hoisting of the boom 8. The work table 16 is swiveled by a swiveling motor 17 built into the work table bracket 15.

[0025] An upper operating device 18 (see FIG. 6) is provided on the work platform 16. This upper operating device 18 is provided with operating levers for rotating the swivel base 6, raising and lowering the boom 8, and swinging the work platform 16. An operator on the work platform 16 can operate the operating levers to operate the swivel base 6, the boom 8, etc. (collectively referred to as "boom operation"). A sub-boom device 20 is attached to the upper end of the vertical post 13. This sub-boom device 20 is composed of a sub-boom member 21 that is a long, rod-shaped member with a rectangular cross section and has a sheave 22 detachably attached to its tip, a boom derrick device 30 that raises and lowers the sub-boom member 21, and a swivel device 40 that swivels the boom derrick device 30. Here, the sub-boom device 20 shown in FIG. 1 is in a stored state.

[0026] Next, the detailed configuration of the sub-boom device 20 will be described with reference to Figures 2 and 3. Figure 2 shows the exterior of the sub-boom device 20, with Figure 2(a) being a side view of the sub-boom device 20 and Figure 2(b) being a rear view seen from the direction of arrow A shown in Figure 2(a). Note that the work platform bracket 15 and oscillating motor 17 shown in Figure 1 are not shown in Figure 2. Figure 3 is an exploded view of the hoisting device 30 that raises and lowers the sub-boom member 21, with the left-hand figure showing the side of the hoisting device 30 and the right-hand figure showing the rear of the hoisting device 30. Furthermore, the vertical post 13, sub-boom member 21, and swivel device 40 shown in Figure 2 are not shown in this figure.

[0027] As shown in FIG. 2, the swivel device 40 is composed of a fixed gear 41, a drive gear 42, and a drive motor 43. The fixed gear 41 is fixed to the vertical post 13. The base 31 is attached to the vertical post 13 in a state where it can swivel relative to the vertical post 13 and the fixed gear 41. The drive gear 42 is attached to a spline shaft (drive shaft) of a drive motor 43 fixed to the base 31, and meshes with the fixed gear 41 to transmit the driving force of the drive motor 43 to the fixed gear 41. This allows the swivel control of the base 31 (and therefore the elevation device 30) to be performed by controlling the drive of the drive motor 43. The drive gear 42 can be disengaged from the fixed gear 41, and when the meshing between the drive gear 42 and the fixed gear 41 is released, the base 31 can be manually rotated.

[0028] As shown in Figure 3, the base 31 is provided with a derrick bracket support shaft 31a and a working hydraulic cylinder mounting shaft 31b. The derrick bracket support shaft 31a is inserted into a derrick bracket mounting hole 32a in the derrick bracket 32, and supports the derrick bracket 32 ​​rotatably around the derrick bracket support shaft 31a. The point at which the base 31 supports the derrick bracket 32 ​​is referred to as the second pivot point (symbol β in Figure 2(a)). The working hydraulic cylinder mounting shaft 31b is inserted into a cylinder mounting hole 35a provided at the base end of the cylinder tube of the working hydraulic cylinder 35, and supports the working hydraulic cylinder 35 rotatably around the working hydraulic cylinder mounting shaft 31b.

[0029] The derrick bracket 32 ​​is provided with a derrick bracket mounting hole 32a, a working hydraulic cylinder mounting shaft 32b, a storage hydraulic cylinder mounting shaft 32c, and a storage bracket support shaft 32d. Of these, the working hydraulic cylinder mounting shaft 32b is inserted into a cylinder mounting hole 35b provided at the rod tip of the working hydraulic cylinder 35, and supports the working hydraulic cylinder 35 rotatably around the working hydraulic cylinder mounting shaft 32b. The storage hydraulic cylinder mounting shaft 32c is inserted into a cylinder mounting hole 36b provided at the base end of the cylinder tube of the storage hydraulic cylinder 36, and supports the storage hydraulic cylinder 36 rotatably around the storage hydraulic cylinder mounting shaft 32c. The storage bracket support shaft 32d is inserted into a storage bracket mounting hole 33a of the storage bracket 33, and supports the storage bracket 33 rotatably around the storage bracket support shaft 32d. Here, the point at which the derrick bracket 32 ​​pivotally supports the stowage bracket 33 is referred to as the first pivot point (symbol α in FIG. 2(a)). The derrick bracket 32 ​​is also provided with an abutment member 37, which abuts against the sub-boom holder 34 and supports the stowage bracket 33 when the angle formed between the derrick bracket 32 ​​and the stowage bracket 33 is 0°. This abutment member 37 functions as a restricting member that restricts the sub-boom member 21 from becoming a depression angle.

[0030] The storage bracket 33 is provided with a storage bracket mounting hole 33a, a storage hydraulic cylinder mounting shaft 33b, and a winch mounting portion 33c. Of these, the storage hydraulic cylinder mounting shaft 33b is inserted into a cylinder mounting hole 36a provided at the rod tip of the storage hydraulic cylinder 36 and supports the storage hydraulic cylinder 36 rotatably around the storage hydraulic cylinder mounting shaft 33b. The winch mounting portion 33c is a plate-shaped member to which the winch 23 (see FIG. 2) can be fixed with a bolt or the like. The winch 23 has a drum around which the winch wire is wound and a winch motor 23a (see FIG. 7), which will be described later. The winch motor 23a is driven to rotate the drum, thereby winding or unwinding the winch wire. A sub-boom holder 34, which holds the sub-boom member 21 and has a rectangular cross section, is provided on the storage bracket 33, allowing the sub-boom member 21 to pass therethrough. The sub-boom holder 34 is provided with a pin hole (not shown) for inserting the fixing pin 24 shown in FIG. 2. By aligning the position of this pin hole with the position of one of the multiple fixing position holes 21a (see FIG. 2(a)) provided in the sub-boom member 21 and inserting the fixing pin 24 into the pin hole and the fixing position hole 21a, the length of the sub-boom member 21 protruding from the sub-boom holder 34 can be adjusted.

[0031] In the hoisting device 30 shown in Figure 3, the hoisting bracket 32 ​​and the storage bracket 33 form a first link mechanism, with the hoisting bracket 32 ​​being the fixed side of the first link mechanism and the storage bracket 33 being the movable side of the first link mechanism. Furthermore, the base 31 and the hoisting bracket 32 ​​form a second link mechanism, with the base 31 being the fixed side of the second link mechanism and the hoisting bracket 32 ​​being the movable side of the second link mechanism. The working hydraulic cylinder 35, the storage hydraulic cylinder 36, and the drive motor 43 shown in Figure 2 can be controlled and driven by the upper operating device 18 (see Figure 6), which will be described later.

[0032] Next, the movement of each part when the sub-boom device 20 is stowing will be described with reference to Figures 4 to 6. Here, Figures 4 and 5 are diagrams showing the movement of each part until the sub-boom device 20 is stowing, and in these figures, the swivel device 40 is not shown, and the portion on the tip side of the sub-boom member 21 is not shown. Also, Figure 6 is a plan view of the aerial work platform vehicle 1 with the sub-boom device 20 stowing, showing the portion around the tip of the boom 8. In Figures 4 to 6, the same parts as those shown in Figures 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0033] FIG. 4(a) shows the state of the derrick device 30 when the sub-boom member 21 is horizontal. In this state, the working hydraulic cylinder 35 and the storage hydraulic cylinder 36 are both fully retracted, and the sub-boom holder 34 is supported by abutment members 37 (see FIG. 3) provided on the derrick bracket 32. Here, the state in which the storage hydraulic cylinder 36 is fully retracted is referred to as the work-ready state. The working hydraulic cylinder 35 is activated when work is performed using the sub-boom device 20, and can raise and lower the derrick bracket 32 ​​relative to the base 31 within a range from horizontal to vertical for the sub-boom member 21. When the working hydraulic cylinder 35 is extended from the state shown in FIG. 4(a), the derrick bracket 32 ​​rises and falls relative to the base 31 around the second pivot point β, as shown in FIG. 4(b). Then, as shown in Figure 4(c), when the sub boom member 21 becomes vertical, part a of the derrick bracket 32, which is surrounded by a dashed line in Figure 4(b), comes into contact with part b of the base 31, which is also surrounded by a dashed line in Figure 4(b), thereby restricting the angle of the sub boom member 21 with respect to the base 31 so that it does not exceed a right angle. In this way, when work is performed using the sub boom device 20, the sub boom member 21 is raised and lowered within a range from horizontal to vertical by extending and retracting the work hydraulic cylinder 35.

[0034] To stow the sub-boom unit 20, with the sub-boom member 21 raised vertically, the storage hydraulic cylinder 36 is extended as shown in FIG. 5(a), and the storage bracket 33 is rotated about the first pivot fulcrum α so that the sub-boom member 21 is lowered (i.e., turned upside down) in the direction opposite to the direction in which it is lowered during operation (clockwise in FIG. 5(a)). When the storage hydraulic cylinder 36 is fully extended, the sub-boom member 21 assumes the stowed position as shown in FIG. 5(b). The fully extended state of the storage hydraulic cylinder 36 is referred to as a stowable state. At this time, the position of the first pivot fulcrum α is lower than the position of the second pivot fulcrum β. This allows the highest position of the storage bracket 33 to be lowered by t1 from the highest position of the derrick bracket 32. Furthermore, as shown by the dashed-dotted line in FIG. 1, when the sub-boom unit 20 is in the stowed state, the derrick bracket 32 ​​is lower than the top surface of the work platform 16. This allows the overall height of the aerial work platform vehicle 1 to be kept low, improving the running stability of the aerial work platform vehicle 1 and expanding the options for routes that can be traveled.

[0035] Furthermore, when the sub-boom device 20 is put into the stowed state, the swivel device 40 is swiveled until the sub-boom member 21, which is in a storable state, is positioned so that it overlaps the boom 8, as shown in the plan view of Fig. 6. By storing the sub-boom device 20 in this state, the sub-boom member 21 does not get in the way when a worker descends from the work platform 16 to the lifting step ST, or when the worker boards the work platform 16 from the lifting step ST, and there is no risk of the sub-boom member 21 coming into contact with vertical structures around the road (for example, utility poles or building walls) when the boom 8 is raised or lowered.

[0036] Furthermore, in the sub boom device 20 described above, the sub boom holder 34 is disposed between the first pivot fulcrum α and the second pivot fulcrum β, and when the sub boom member 21 is raised vertically, the sub boom holder 34 abuts against the abutment member 37, which is the fixed side of the first link mechanism. Therefore, for example, during temporary support work for electric wires performed with the sub boom member 21 raised vertically, the load and moment acting on the sub boom member 21 are borne by the first pivot fulcrum α and the abutment member 37, and no load is applied to the storage hydraulic cylinder 36. As a result, the storage hydraulic cylinder 36 only needs to have a thrust sufficient to rotate the storage bracket 33 and the sub boom member 21 until they assume the storage position, and therefore a hydraulic cylinder with a low thrust can be used for the storage hydraulic cylinder 36.

[0037] Next, the configuration of the main hydraulic circuits and the configuration of the control system that controls each hydraulic actuator in this embodiment will be described with reference to Figure 7. Figure 7 is a schematic diagram of the main hydraulic circuits extending from the vehicle body 2, via the swivel base 6 and boom 8, to the work platform 16, and also shows the configuration of the control system that controls the various hydraulic actuators included in the hydraulic circuits. Note that the same reference numerals are used to designate the same parts as those shown in Figures 1 to 6, and detailed description thereof will be omitted.

[0038] The vehicle body 2 is provided with a hydraulic oil tank 50 that stores hydraulic oil, and the hydraulic oil stored in the hydraulic oil tank 50 is pressurized by a hydraulic pump 51 and supplied to a jack operating valve 52 via a first pump oil passage LP1. The jack operating valve 52 is an electromagnetic proportional control valve that electromagnetically drives an internal spool based on a control signal from the lower controller 12 to control the supply direction and amount of hydraulic oil to the jack cylinder 5. This causes the jack cylinder 5 to extend and retract according to the supply direction and amount of hydraulic oil. The lower operating device 11 is provided with an operating lever for operating the jack cylinder 5, and the lower controller 12 generates a control signal according to operation of the operating lever of the lower operating device 11 and outputs it to the jack operating valve 52.

[0039] The hydraulic oil supplied to the jack operation valve 52 is also supplied to the boom operation valve 53 through the second pump oil line LP2. The boom operation valve 53 is composed of electromagnetic proportional control valves corresponding to the swing motor 7, derrick cylinder 9, and telescopic cylinder 10. Each of these electromagnetic proportional control valves electromagnetically drives an internal spool based on a valve control signal from the lower controller 12, controlling the direction and amount of hydraulic oil supplied to the swing motor 7, derrick cylinder 9, and telescopic cylinder 10. This causes the derrick cylinder 9 and telescopic cylinder 10 to extend and retract, and the swing motor 7 to rotate forward or reverse. Note that because the derrick cylinder 9 and telescopic cylinder 10 are mounted on the swivel base 6, hydraulic oil is supplied to these cylinders via a swivel joint 54. Also, Figure 7 does not show the return oil lines (oil lines through which hydraulic oil supplied to each hydraulic actuator returns to the hydraulic oil tank 50) in the hydraulic circuit inside the vehicle body 2.

[0040] The lower operating device 11 is provided with a boom rotation switch for instructing the rotation direction (forward rotation or reverse rotation) of the swivel base 6, a boom hoist switch for instructing the raising and lowering movement of the boom 8 (raising or lowering), and a boom extension / retraction switch for instructing the telescopic movement of the boom 8 (extending or retracting). As a result, when the boom rotation switch is operated, for example, the lower controller 12 outputs a control signal to the electromagnetic proportional control valve corresponding to the swing motor 7 to rotate the swing motor 7 in the instructed swing direction. Furthermore, when the boom hoist switch is operated, the lower controller 12 outputs a control signal to the electromagnetic proportional control valve corresponding to the boom hoist cylinder 9 to extend the boom hoist cylinder 9 (when "raising" is instructed) or a control signal to retract the boom hoist cylinder 9 (when "lowering" is instructed). Furthermore, when the boom extension / retraction switch is operated, the lower controller 12 outputs a control signal to the electromagnetic proportional control valve corresponding to the telescopic cylinder 10 to extend the telescopic cylinder 10 (when "extending" is instructed) or a control signal to retract the boom 8 (when "retracting" is instructed).

[0041] The hydraulic oil supplied to the boom operation valve 53 is also supplied to the upper operation valve 110 through the third pump oil passage LP3, via the swivel joint 54, and the fourth pump oil passage LP4 arranged inside the boom 8. The upper operation valve 110 is composed of manual control valves corresponding to each of the various hydraulic actuators (swing motor 17, winch motor 23a, working hydraulic cylinder 35, and retracting hydraulic cylinder 36) provided on the work platform 16 and its surrounding area (hereinafter also referred to as the "upper part"). Each of the manual control valves described above controls the supply direction and amount of hydraulic oil to the swing motor 17, winch motor 23a, working hydraulic cylinder 35, and retracting hydraulic cylinder 36 by moving an internal spool in accordance with the tilt direction of various operation levers provided on the upper operation device 18.

[0042] The upper operating device 18 is provided with a swing lever for commanding the swing direction (right or left) of the platform 16, a winch lever for commanding the operation of the winch 23 (winding or paying out), a sub-boom hoist lever for commanding the raising and lowering movement of the sub-boom member 21 (raising or lowering), and a sub-boom stowage lever for commanding whether the storage hydraulic cylinder 36 is in the above-mentioned work-ready state or retractable state (working or retracting). As a result, for example, when the swing lever is tilted, the manual control valve corresponding to the swing motor 17 supplies hydraulic oil to the swing motor 17 so that the platform 16 swings in the swing direction corresponding to the tilt direction of the lever. Also, when the winch lever is tilted, the manual control valve corresponding to the winch motor 23a supplies hydraulic oil to the winch motor 23a so that the winch 23 performs a winding or paying out movement depending on the tilt direction of the lever.

[0043] The oscillating motor 17 and the winch motor 23a are each connected to a first drain oil passage LD1 for returning hydraulic oil leaked from inside to the hydraulic oil tank 50. Check valves are provided between these hydraulic actuators and the first drain oil passage LD1 to prevent backflow of hydraulic oil from the first drain oil passage LD1. Specifically, a first check valve 61 is provided between the oscillating motor 17 and the first drain oil passage LD1, and a second check valve 62 is provided between the winch motor 23a and the first drain oil passage LD1.

[0044] When the sub-boom hoist lever of the upper operating device 18 is operated, the manual control valve corresponding to the working hydraulic cylinder 35 supplies hydraulic oil to the working hydraulic cylinder 35 so that the sub-boom member 21 raises or lowers depending on the tilt direction of the lever. As a result, when the sub-boom hoist lever is tilted to the "raise" side, for example, hydraulic oil is supplied to the bottom side of the working hydraulic cylinder 35, extending the rod of the working hydraulic cylinder 35. As a result, the sub-boom member 21 raises or lowers as shown in Figure 4(a) → (b) → (c).

[0045] When the sub-boom stow lever of the upper operating device 18 is operated, the manual control valve corresponding to the stowage hydraulic cylinder 36 supplies hydraulic oil to the stowage hydraulic cylinder 36 so that the sub-boom member 21 moves up or down from a vertically raised state toward a storable state, depending on the tilt direction of the lever. As a result, when the sub-boom stowage lever is tilted to the "storage" side, for example, hydraulic oil is supplied to the bottom side of the stowage hydraulic cylinder 36, extending the rod of the stowage hydraulic cylinder 36. As a result, the sub-boom member 21 moves down as shown in Figure 4(c) → Figure 5(a) → (b). On the other hand, when the sub-boom stowage lever is tilted to the "operation" side, hydraulic oil is supplied to the rod side of the stowage hydraulic cylinder 36, retracting the rod of the stowage hydraulic cylinder 36. 7, an oil passage connected to the first oil drain passage LD1 is provided between the single pilot check valve 64 and the rod side of the storage hydraulic cylinder 36, and a third check valve 65 is provided in this oil passage. This prevents hydraulic oil flowing between the single pilot check valve 64 and the rod side of the storage hydraulic cylinder 36 from flowing into the first oil drain passage LD1.

[0046] When the sub-boom hoist lever is tilted to the "lowering" side, the manual control valve corresponding to the working hydraulic cylinder 35 supplies hydraulic oil to the rod side of the working hydraulic cylinder 35, causing the rod of the working hydraulic cylinder 35 to retract. As a result, the sub-boom member 21 lowers as shown in Figure 4(c) -> (b) -> (a).

[0047] Hydraulic oil returning from each of the hydraulic actuators to the upper operation valve 110 is discharged to a first return oil passage LR1. The first return oil passage LR1 passes through the interior of the boom 8 and is connected to a second return oil passage LR2 that leads to the hydraulic oil tank 50 via a swivel joint 54. The first drain oil passage LD1 also passes through the interior of the boom 8 and is connected to an upper operation changeover valve 55 provided on the swivel base 6. The upper operation changeover valve 55 is an electromagnetic changeover valve that connects the first drain oil passage LD1 to either the second drain oil passage LD2 or the fifth pump oil passage LP5 in accordance with a changeover signal output from a swivel base controller 56 provided on the swivel base 6. One end of the second drain oil passage LD2 is connected to port a of the upper operation changeover valve 55, and the other end is connected to a third drain oil passage LD3 that leads to the hydraulic oil tank 50 via the swivel joint 54. One end of the fifth pump oil passage LP5 is connected to the b port of the upper operation changeover valve 55, and the other end is connected to an oil passage that connects the boom operation valve 53 and the rod side of the telescopic cylinder 10.

[0048] The upper actuation switching valve 55 is configured so that, when no switching signal is output from the swivel controller 56, the spool is held by the biasing force of a spring in a position where it connects the first drain oil line LD1 to the second drain oil line LD2. When a switching signal is output from the swivel controller 56, the spool is moved by the suction force of the solenoid to a position where it connects the first drain oil line LD1 to the fifth pump oil line LP5. The swivel controller 56 is electrically connected to the lower controller 12 via a slip ring 57, and outputs the above-mentioned switching signal to the upper actuation switching valve 55 when an upper actuation signal is output from the lower controller 12. Furthermore, when no upper actuation signal is output from the lower controller 12, the output of the above-mentioned switching signal is stopped. The lower actuation device 11 is provided with an upper actuation switch that enables the storage hydraulic cylinder 36 to be operated from the lower actuation device 11. When this upper operation switch is turned on, the lower controller 12 outputs an upper operation signal to the swivel controller 56, and when the upper operation switch is turned off, the output of the upper operation signal is stopped.

[0049] In addition to the first return oil passage LR1, a total of five oil passages are arranged inside the boom 8: the fourth pump oil passage LP and the first drain oil passage LD1 described above, and two oil passages connecting the upper leveling cylinder 14a and the lower leveling cylinder 14b. One of these two oil passages connects the bottom side of the upper leveling cylinder 14a to the bottom side of the lower leveling cylinder 14b. The remaining oil passage connects the rod side of the upper leveling cylinder 14a to the rod side of the lower leveling cylinder 14b. As a result, when the boom 8 is raised, the rod of the lower leveling cylinder 14b extends, supplying hydraulic oil to the rod side of the upper leveling cylinder 14a and causing the rod of the upper leveling cylinder 14a to retract. Furthermore, when the boom 8 is lowered, the rod of the lower leveling cylinder 14b contracts, supplying hydraulic oil to the bottom side of the upper leveling cylinder 14a and causing the rod of the upper leveling cylinder 14a to extend.

[0050] Furthermore, in addition to the above-mentioned oil passages, an optical fiber cable Fb is arranged inside the boom 8. This optical fiber cable Fb connects the swivel controller 56 and the upper controller 100. The upper controller 100 receives detection signals from various sensors 101 that detect the swing angle of the work platform 16, the load of materials and other items loaded on the work platform 16, and the suspended load of the winch 23, and the like. The upper controller 100 converts these detection signals into optical signals and sends them to the swivel controller 56. When the swivel controller 56 receives various detection signals from the upper controller 100, it converts them into electrical signals and outputs them to the lower controller 12. Based on the various detection signals received, the lower controller 12 controls the swivel motor 7, the derrick cylinder 9, and the telescopic cylinder 10 so that the aerial work vehicle moves the work platform 16 within a safe area.

[0051] Next, a method for operating the storage hydraulic cylinder 36 from the lower operating device 11 when the sub-boom device 20 and the boom 8 are in the stored state as shown in FIG. 1 in the above-described hydraulic circuit will be described. First, when the above-described upper operation switch is turned on in the lower operating device 11, the lower controller 12 outputs an upper operation signal to the swivel base controller 56. This causes the swivel base controller 56 to output a switching signal to the upper operation switchover valve 55, which moves the spool of the upper operation switchover valve 55 and connects the first drain oil line LD1 to the fifth pump oil line LP5. Then, when an operation to retract the boom 8 is performed in the lower operating device 11, since the boom 8 is in the fully retracted state, hydraulic oil is supplied to the b port of the upper operation switchover valve 55 and discharged to the first drain oil line LD1. Alternatively, when the above-described upper operation switch is turned on in the lower operating device 11, the lower controller 12 may output an upper operation signal to the swivel base controller 56 and simultaneously output a retraction operation signal for the boom 8.

[0052] As a result, when the pressure of the hydraulic oil discharged into the first drain oil passage LD1 exceeds the cracking pressure of the third check valve 65, the hydraulic oil passes through the third check valve 65 and is supplied to the rod side of the storage hydraulic cylinder 36. At this time, the first check valve 61 and the second check valve 62 prevent backflow of hydraulic oil to the swing motor 17 and the winch motor 23a, preventing the drain ports of these hydraulic actuators from being damaged by excessive hydraulic pressure. As a result, the rod of the storage hydraulic cylinder 36 contracts, causing the storage bracket 33 and the sub-boom member 21 to rise and fall. As a result, even if the platform 16 is lowered to the ground by swinging the swivel base 6 and then lowering the boom 8 to load materials to be used for high-altitude work onto the platform 16, there is no risk of the tip of the sub-boom member 21 hitting the boom 8.

[0053] In this way, because the sub-boom device 20 can be operated from the lower operating device 11, there is no need for the operator to climb onto the work platform 16 to operate the sub-boom device 20. This reduces the burden on the operator and the amount of work required, and shortens the operation time. Furthermore, because the existing drain oil passage is used as the oil passage for operating the storage hydraulic cylinder 36, there is no need to add a new oil passage, and there is no need to expand the internal space of the boom 8 or increase manufacturing costs.

[0054] In this embodiment, the hydraulic actuator operable from the lower operating device 11 is the storage hydraulic cylinder 36, but it is not limited to this and may be another hydraulic actuator. For example, it may be the working hydraulic cylinder 35, or in the case of an aerial work vehicle in which a swivel arm is interposed between the work platform and the tip of the boom, the swivel movement of this swivel arm may be operable from the lower operating device 11.

[0055] [Second embodiment] Next, the configuration of the main hydraulic circuits and the configuration of the control system for controlling each hydraulic actuator in a second embodiment of the present invention will be described with reference to Figure 8. The structures of each part of the aerial work vehicle 1 described with reference to Figures 1 to 6 in the first embodiment are the same in the second embodiment. The configurations of the hydraulic circuits and their control systems in the vehicle body 2, swivel base 6, and boom 8 in Figure 8 are the same as the configurations of the hydraulic circuits and their control systems in the vehicle body 2, swivel base 6, and boom 8 shown in Figure 7. Below, the configurations of the hydraulic circuits and their control systems in the work platform 16 and its surrounding area (upper part) will be described with reference to Figure 8. In Figure 8, the same components as those shown in Figures 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0056] In Figure 8, the upper operation valve 110' is composed of multiple electromagnetic proportional control valves, and each electromagnetic proportional control valve is provided in a one-to-one correspondence with the swing motor 17, winch motor 23a, working hydraulic cylinder 35, and storage hydraulic cylinder 36. The upper controller 100' outputs valve control signals to each electromagnetic proportional control valve constituting the upper operation valve 110' based on operation signals output from the upper operation device 18'. As a result, each electromagnetic proportional control valve of the upper operation valve 110' electromagnetically drives its internal spool based on the valve control signal, controlling the direction and amount of hydraulic oil supplied to the swing motor 17, winch motor 23a, working hydraulic cylinder 35, and storage hydraulic cylinder 36. As a result, the swing motor 17 swings left or right, the winch motor 23a rotates forward or reverse, and the working hydraulic cylinder 35 and storage hydraulic cylinder 36 extend or retract.

[0057] The upper operating device 18' is provided with a swing switch for instructing the swing direction (right or left) of the swing motor 17, a winch switch for instructing the operation (winding or paying out) of the winch 23, a sub-boom hoist switch for instructing the raising and lowering movement (raising or lowering) of the sub-boom member 21, and a sub-boom stowing switch for instructing whether the storage hydraulic cylinder 36 is in the above-mentioned work ready state or retractable state (working or retracting). Thus, when the swing switch is operated, for example, the upper controller 100' outputs a valve control signal to the electromagnetic proportional control valve corresponding to the swing motor 17 to swing the work platform 16 in the swing direction specified by the swing switch. Also, when the winch switch is operated, it outputs a valve control signal to the electromagnetic proportional control valve corresponding to the winch motor 23a to cause the winch motor 23a to perform the operation (winding or paying out) specified by the winch switch. Furthermore, when the sub-boom hoist switch is operated, a valve control signal is output to the electromagnetic proportional control valve corresponding to the working hydraulic cylinder 35, causing the sub-boom member 21 to perform the operation (raising or lowering) specified by the sub-boom hoist switch. Furthermore, when the sub-boom stowing switch is operated, a valve control signal is output to the electromagnetic proportional control valve corresponding to the storage hydraulic cylinder 36, causing the storage bracket 33 to perform the operation (working or storage) specified by the sub-boom stowing switch.

[0058] In this embodiment, a sub-boom retraction switch is provided in the lower operating device 11', and an operation signal from this switch is output to the upper controller 100' via the lower controller 12' and the swivel base controller 56'. As a result, the upper controller 100' outputs a valve control signal to the electromagnetic proportional control valve corresponding to the retraction hydraulic cylinder 36 of the upper operating valve 110' in accordance with the operation signal from the sub-boom retraction switch provided in the lower operating device 11'. In addition, the lower operating device 11' is provided with an upper power switch to enable power supply from the lower operating device 11' to the upper controller 100'.

[0059] Like the upper controller 100 of the first embodiment, the upper controller 100' receives detection signals from the various sensors 101 and is also equipped with various power-related terminals, as described below. The BTT1 terminal, the BTT2 terminal, and the A terminal are all power input terminals. When power is supplied from the battery 102 to any one of these terminals, the upper controller 100' enters an operating state. A power relay 70 is provided between the BTT1 terminal and the battery 102. When an excitation signal is output from the C port of the upper controller 100' to an internal coil, the power relay 70 closes its contacts to supply power from the battery 102 to the BTT1 terminal. When no excitation signal is output from the C port, the contacts are opened, cutting off the power supplied to the BTT1 terminal. A power switch 71 is provided between the BTT2 terminal and the battery 102. When the power switch 71 is turned on, the contacts are closed, supplying power from the battery 102 to the BTT2 terminal. When the power switch 71 is turned off, the contacts are opened, cutting off the power supplied to the BTT2 terminal.

[0060] A timer relay 72 that performs an off-delay operation is provided between the A port of the upper controller 100′ and the battery 102. When the coil of the timer relay 72 is excited, the contacts close and power from the battery 102 is supplied to the A port of the upper controller 100′. In addition, the contacts remain closed even after the coil of the timer relay 72 is no longer excited, and after a predetermined time has passed, the contacts of the timer relay 72 open and the power supplied to the A port of the upper controller 100′ is cut off. A hydraulic switch 73 is provided between the coil of the timer relay 72 and the battery 102. When the pressure of the hydraulic oil supplied from the first drain oil passage LD1 is applied to the pressure receiving portion of the hydraulic switch 73, the contacts of the hydraulic switch 73 close and power from the battery 102 is supplied to the coil of the timer relay 72. In addition, when the pressure of the hydraulic oil is no longer applied to the pressure receiving portion of the hydraulic switch 73, the contacts of the hydraulic switch 73 open and the power to the coil of the timer relay 72 is cut off.

[0061] 8 having the above configuration, a method for turning on the power to the upper controller 100' from the lower operating device 11' will be described. First, when the above-mentioned upper power switch is turned on in the lower operating device 11', the lower controller 12' outputs an upper operating signal to the swivel base controller 56. This causes the swivel base controller 56 to output a switching signal to the upper operation switchover valve 55, and as a result, the spool of the upper operation switchover valve 55 moves and the first drain oil line LD1 is connected to the fifth pump oil line LP5. Then, when an operation to retract the boom 8 is performed in the lower operating device 11', the boom 8 is in a fully retracted state, so hydraulic oil is supplied to the b port of the upper operation switchover valve 55 and discharged into the first drain oil line LD1. As a result, hydraulic oil pressure is applied to the pressure receiving part of the hydraulic switch 73, but the first check valve 61 and the second check valve 62 prevent backflow of hydraulic oil to the oscillating motor 17 and the winch motor 23a, so there is no risk of excessive hydraulic pressure being applied to the drain ports of these hydraulic actuators, causing them to malfunction.

[0062] When the pressure of the hydraulic oil is applied to the pressure receiving part of the hydraulic switch 73, the contact of the hydraulic switch 73 is closed, and power from the battery 102 is supplied to the coil of the timer relay 72, and the contact of the timer relay 72 is closed. When power from the battery 102 is supplied to the A port of the upper controller 100' as a result of the closure of the contact of the timer relay 72, the upper controller 100' starts up its internal CPU and then enters an operating state. When the upper controller 100' enters an operating state, an excitation signal is output from the C port to the coil of the power supply relay 70. Here, in the timer relay 72, the time from when the excitation signal is no longer supplied to the coil to when the contact is broken is set to be at least longer than the time from when power is supplied to the A port of the upper controller 100', the internal CPU starts up, and then the excitation signal is output from the C port.

[0063] As a result, the contacts of the power relay 70 close, and power from the battery 102 is supplied to the BTT1 terminal of the upper controller 100'. When power is supplied to the BTT1 terminal, the upper controller 100' enters an operating state. Furthermore, while power from the battery 102 is supplied to the BTT1 terminal, the excitation signal output from the C port is maintained, so even if the power supply from the battery 102 to the A port of the upper controller 100' is cut off, the operating state of the upper controller 100' is maintained. Furthermore, when the power switch 71 provided between the BTT2 terminal and the battery 102 is turned on, power from the battery 102 is supplied to the BTT2 terminal. When power is supplied to the BTT2 terminal, output from the C port stops and the power supply from BTT1 stops. As a result, power is supplied to the upper controller 100' only to the BTT2 terminal, and therefore when the power switch 71 is turned off, the power supply to the upper controller 100' is cut off and the upper controller 100' stops operating.

[0064] When the upper controller 100' is in an operating state, it converts the detection signals output from the various sensors 101 into optical signals and sends them to the swivel controller 56', and can also control the operation of the storage hydraulic cylinder 36 from the lower operating device 11'. Furthermore, if there is no change in the detection signals output from the various sensors 101 for a predetermined time after power from the battery 102 is supplied to the BTT1 terminal and no operating signal is output from the upper operating device 18' or the lower operating device 11', the excitation signal that has been output from the C port to the power relay 70 is stopped, and the power supply to the upper controller 100' is stopped, so-called an auto-off function may be provided.

[0065] In this way, since various hydraulic actuators provided on the upper part can be operated from the lower operating device 11', there is no need for the operator to board the work platform 16 to operate the sub-boom device 20. This reduces the operator's burden and the amount of work required, and shortens the work time. Furthermore, when the upper controller 100' is in an operating state, detection signals such as the swing angle of the work platform 16 detected by the various sensors 101, the load of materials and the like placed on the work platform 16, and the suspended load of the winch 23 are transmitted to the lower controller 12'. This allows the lower controller 12' to determine the attitude and load of the work platform 16, so that the work platform can be safely moved close to the ground without disabling the operation of the boom 8 by the lower operating device 11'.

[0066] In the above-described embodiments, the oil passage branching off from the oil passage connected to the rod side of the telescopic cylinder 10 is connected to the b port of the upper actuation changeover valve 55. However, this is not limiting. If there is an oil passage that can supply enough oil pressure to raise or lower the sub-boom member 21 and the storage bracket 33 by the storage hydraulic cylinder 36, or enough oil pressure to turn on the hydraulic switch 73, the oil passage may be branched off and connected to the b port of the upper actuation changeover valve 55. [Explanation of symbols]

[0067] 1. Aerial work platform 8. Boom 9. Drilling cylinder 10 Telescopic cylinder 11,11' Lower operating device 12,12' Lower Controller 16 Workbench 17 Oscillating motor 18,18' Upper operating device 20 Sub-boom device 21 Sub-boom member 33 Storage bracket 34 Sub-boom holder 35 Hydraulic cylinder for work 36 Storage hydraulic cylinder 55 Top-acting switching valve 61 First check valve 62 Second check valve 65 Third check valve 73 Oil pressure switch 100,100' Upper Controller 110,110' Top-operated valve 102 Battery

Claims

1. The car body and a hydraulic oil tank provided on the vehicle body and configured to store hydraulic oil; a hydraulic pump that applies pressure to the hydraulic oil stored in the hydraulic oil tank and discharges it; a plurality of lower hydraulic actuators provided on the vehicle body and actuated by hydraulic pressure; a lower operating device provided on the vehicle body; a lower hydraulic oil control device that controls the amount and direction of supply of hydraulic oil discharged from the hydraulic pump to the plurality of lower hydraulic actuators in accordance with an operation performed on the lower operating device; a boom provided on the vehicle body so as to be at least capable of being raised and lowered; a work platform provided at the tip of the boom; a plurality of upper hydraulic actuators provided at the tip of the boom and operated by hydraulic pressure; an upper operating device provided on the workbench; an upper hydraulic oil control device that controls the supply amount and supply direction of the hydraulic oil discharged from the hydraulic pump to the plurality of upper hydraulic actuators in accordance with an operation performed on the upper operating device; a drain line disposed through the interior of the boom for returning hydraulic oil leaked from a predetermined upper hydraulic actuator among the plurality of upper hydraulic actuators to the hydraulic oil tank; a check valve provided in a line connecting a specific upper hydraulic actuator among the plurality of upper hydraulic actuators to the drain line, the check valve preventing the flow of hydraulic oil from the specific upper hydraulic actuator to the drain line; a switching valve that is provided in the drain line and switches whether or not the hydraulic oil discharged from the hydraulic pump is allowed to flow into the drain line, the lower hydraulic oil control device switches the switching valve in response to an operation performed on the lower operating device so that the hydraulic oil discharged from the hydraulic pump flows to the drain line, The specific upper hydraulic actuator is operated by being supplied with hydraulic oil discharged from the hydraulic pump via the drain pipe.

2. a sub-boom device including a sub-boom member and a boom hoisting device that supports the sub-boom member so that the sub-boom member can be raised and lowered; the specific upper hydraulic actuator raises or lowers the boom hoisting device that raises or lowers the sub-boom member; the sub-boom device is placed in a stowed state by rotating the sub-boom member beyond the vertical position in a direction opposite to the direction in which the sub-boom member is lowered during work, 2. The aerial work vehicle according to claim 1, wherein when hydraulic oil discharged from the hydraulic pump is supplied via the drain line while the sub-boom device is in a stored state, the specific upper hydraulic actuator rotates the sub-boom member in a direction in which the sub-boom member assumes a vertical position.

3. a drain check valve provided in a line connecting the predetermined upper hydraulic actuator and the drain line, the drain check valve preventing the flow of hydraulic oil from the drain line to the predetermined upper hydraulic actuator; 3. The aerial work platform according to claim 2, wherein the check valve is configured not to be released by the hydraulic pressure of hydraulic oil leaking from the specified upper hydraulic actuator, but to be released by the hydraulic pressure of hydraulic oil discharged from the hydraulic pump.

4. a branch line branching from a line for supplying hydraulic oil discharged from the hydraulic pump to a specific lower hydraulic actuator among the plurality of lower hydraulic actuators and connected to the switching valve; A high-altitude work vehicle as described in any one of claims 1 to 3, characterized in that when the branch pipeline is connected to the drain pipeline by the switching valve, the operation of the specific lower hydraulic actuator is operated by the lower operating device, thereby supplying hydraulic oil via the drain pipeline and operating the specific upper hydraulic actuator.

5. The car body and a hydraulic oil tank provided on the vehicle body and configured to store hydraulic oil; a hydraulic pump that applies pressure to the hydraulic oil stored in the hydraulic oil tank and discharges it; a plurality of lower hydraulic actuators provided on the vehicle body and actuated by hydraulic pressure; a lower operating device provided on the vehicle body; a lower hydraulic oil control device that controls the amount and direction of supply of hydraulic oil discharged from the hydraulic pump to the plurality of lower hydraulic actuators in accordance with an operation performed on the lower operating device; a boom provided on the vehicle body so as to be at least capable of being raised and lowered; a work platform provided at the tip of the boom; a plurality of upper hydraulic actuators provided at the tip of the boom and operated by hydraulic pressure; an upper operating device provided on the workbench; an upper hydraulic oil control device that controls the supply amount and supply direction of the hydraulic oil discharged from the hydraulic pump to the plurality of upper hydraulic actuators in accordance with an operation performed on the upper operating device; a battery for powering the upper hydraulic control device; a hydraulic switch that is provided between the upper hydraulic oil control device and the battery and is turned on by hydraulic pressure supplied from an external source; a drain line disposed through the interior of the boom for returning hydraulic oil leaked from a predetermined upper hydraulic actuator among the plurality of upper hydraulic actuators to the hydraulic oil tank; a switching valve that switches whether or not the hydraulic oil discharged from the hydraulic pump is allowed to flow to the drain line, the lower hydraulic oil control device switches the switching valve in response to an operation performed on the lower operating device so that the hydraulic oil discharged from the hydraulic pump flows to the drain line, The hydraulic switch is turned on when hydraulic oil discharged from the hydraulic pump is supplied through the drain pipe, and supplies power from the battery to the upper hydraulic oil control device.

6. 6. The aerial work platform according to claim 5, further comprising a drain check valve provided in a line connecting the specified upper hydraulic actuator and the drain line, for preventing the flow of hydraulic oil from the drain line to the specified upper hydraulic actuator.

7. a branch line branching from a line for supplying hydraulic oil discharged from the hydraulic pump to a specific lower hydraulic actuator among the plurality of lower hydraulic actuators and connected to the switching valve; 7. A high-altitude work vehicle as described in claim 5 or 6, characterized in that when the branch pipeline is connected to the drain pipeline by the switching valve, the operation of the specific lower hydraulic actuator is operated by the lower operating device to supply hydraulic oil through the drain pipeline and activate the hydraulic switch.

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