JP3869285B2 - Overturn prevention device for aerial work platforms - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
More specifically, the present invention relates to a boom mounted on a vehicle so that it can turn and undulate, and is supported substantially vertically at the tip of the boom regardless of the angle of undulation of the boom. The present invention relates to a tipping prevention device for an aerial work vehicle that includes a vertical post and a work table that is swingably provided on the vertical post and configured to be extendable.
[0002]
[Prior art]
Such an aerial work vehicle generally uses a boom to move the work table to a desired high position so that an operator on the work table can work at a high place. When the platform is moved to a high place, the falling direction moment acting on the vehicle body increases and the vehicle body support tends to become unstable. For this reason, it has been generally practiced to mount an overturn prevention device for preventing an excessive increase in the overturn direction moment on an aerial work vehicle.
[0003]
This overturn prevention device is configured to regulate an operation in which the overturning direction moment that changes with the operation of the boom exceeds a preset reference value (hereinafter, this reference value is referred to as “allowable overturning moment”). Specifically, the allowable work range of the workbench that allows the tipping direction moment to move without exceeding the permissible overturning moment is set in advance, and the boom operation that restricts the workbench to exceed the permissible work range is regulated. Is configured to do.
[0004]
Here, even if the work platform is extended to the other side in the left-right direction of the vehicle while the boom is pivoted to the left-right side of the vehicle, the moment acting on the vehicle by this extension movement is reduced to the falling direction moment. Therefore, even if the extension amount of the work table is increased, there is no possibility that the vehicle falls.
[0005]
[Problems to be solved by the invention]
However, when the amount of extension of the work table increases, the bending moment and the torsional moment acting on the tip of the boom increase, the boom strength cannot be maintained, and the boom may be damaged. In addition, regardless of the extension amount or swing angle of the work table, the fall prevention device assumes that the work table is at a predetermined swing angle with respect to the boom and in a fully contracted state. When configured to calculate the position of the workbench according to the detected value, the workbench swings in the vehicle longitudinal direction with the workbench tip facing in the width direction of the vehicle and the workbench extended. When the vehicle is moved, there arises a problem that even though the work table position is within the allowable work range, the moment in the overturning direction with respect to the longitudinal direction of the vehicle increases and the vehicle may fall in the longitudinal direction.
[0006]
The present invention has been made in view of such a problem, and when the work table is configured to be able to swing and extend, there is no risk of the boom being damaged by the extension of the work table. An object of the present invention is to provide a fall prevention device configured so that the vehicle does not fall in the front-rear direction even when the vehicle is extended and swung.
[0007]
[Means for Solving the Problems]
  In order to solve the above-described problems, an overturning prevention device for an aerial work vehicle according to the present invention includes a boom provided on a vehicle (for example, the vehicle body 7 in the embodiment) so as to be capable of turning and raising and lowering, and a tip of the boom. It can be swung up and downTheAbbreviated regardless of boom undulation angleVerticalA vertical post (e.g., post 37 in the embodiment) supported byThe base end isProvided at the tip of the vertical post so that it can swing in a horizontal plane; andThe tip side isA fall prevention device for an aerial work vehicle (for example, the overfence work vehicle 1 in the embodiment) having a work table that is configured to extend and contract in a horizontal direction with respect to a vertical post, A swing actuator for swinging (for example, a swing motor 46 in the embodiment), a telescopic actuator for extending and contracting a work table (for example, the extension cylinder 49 in the embodiment),From the swing angle position of the platform relative to the vertical post and the amount of extension of the platform relative to the vertical postWork table position detecting means for detecting the position of the front end of the work table with respect to the vertical post (for example, the work table swing angle sensor 61 and the work table extension sensor 63 in the embodiment), Workbench position calculation circuit 80) And the tip position of the workbench detected by the workbench position detection means is the allowable fall direction moment.And considering the moment acting on the boomThe work table position determination means (for example, the determination circuit 81 in the embodiment) for determining whether or not the preset allowable movement range is exceeded and the work table position determination means cause the tip position of the work table to exceed the allowable movement range. If it is determined, the work table is configured to have an operation restricting means (for example, a restricting drive circuit 82 in the embodiment) that restricts the operation of the swing actuator and the telescopic actuator in a direction exceeding the allowable movement range. .
[0008]
  According to the fall prevention device having the above configuration, the work table can swing and extend and expand in the horizontal plane at the tip of the vertical post, and the extension amount and the swing angle of the work table are detected, and the vertical value is detected from these detected values. Calculate the tip position of the work table with respect to the post, and if the calculated tip position of the work table exceeds the allowable movement range, the operation of the swing actuator and telescopic actuator that causes the work table to move in the direction exceeding the allowable movement range Therefore, even if the workbench moves horizontally with respect to the vertical post and the overturning moment acting on the vehicle increases, the overturning moment does not exceed the allowable overturning moment. For this reason, it is possible to prevent the vehicle from falling over. Also work benchWhen these are stretched or swung, theseBending moment and torsion moment with respect to the boom by horizontal movement ofButActionAlthough,Consider the moment when the allowable movement range acts on the boom.Set to prevent damage to the boomBecauseThus, it is possible to prevent the boom from being damaged by the horizontal movement of the work table.
  A vertical post is provided at the tip of the boom so as to be vertically movable, and the vertical post is extended downward so that the workbench swings and expands and contracts with the workbench positioned below the vehicle. It is preferable to be configured to be movable.
  Further, in a boom posture in which the vertical post is located on the side of the vehicle, it is preferable that the movement allowable range is set narrower in the front-rear direction of the vehicle than in the vehicle width direction of the vehicle.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. This embodiment shows an aspect of an overfence work vehicle that performs maintenance work such as painting repair of bridges. First, before describing the overturn prevention device according to the present invention, an overfence work vehicle equipped with the overturn prevention device will be described.
[0010]
As shown in FIG. 1, the overfence work vehicle 1 is configured to be based on a truck vehicle having front and rear wheels 3 and having a driving cabin 5 at the front. An aerial work device 20 is mounted on the vehicle body 7 of the truck vehicle. The work place 20 has a swivel base 21 that is driven by a swivel motor (not shown) so as to be horizontally swivel. A boom 23 pivotally connected to the base end is attached to the swivel base 21. 23 is configured to be raised and lowered by a raising and lowering cylinder 25. The boom 23 is configured such that the proximal boom 23a and the distal boom 23b are combined in a telescopic manner and can be expanded and contracted by a built-in expansion cylinder (not shown). Although the boom 23 has a two-stage telescopic boom configuration here, this may be a three-stage telescopic boom configuration or a multi-stage telescopic boom configuration of more than that.
[0011]
An extension post 27 is attached to the tip of the tip boom 23b so as to be swingable up and down. A link member 29 is pivotally connected to the base portion of the bending post 27, and one end of a post leveling cylinder 31 is pivotally connected to the tip portion thereof. The other end of the post leveling cylinder 31 is pivotally connected to the tip boom 23b. A bending / stretching cylinder 33 is pivotally connected between the distal end portion of the link member 29 and the front surface of the bending / stretching post 27. A holder 35 is attached to the distal end portion of the bent post 27 and can swing up and down. The holder 35 is formed in a hollow rectangular tube shape, and swinging is controlled by a post leveling cylinder 31 and a bending / stretching cylinder 33. The post-leveling cylinder 31 and the hoisting cylinder 25 expand and contract in conjunction with each other, and when the boom 23 is in a horizontal state, the holder 35 is also expanded and contracted so as to be in a horizontal state. The bending / stretching cylinder 33 is configured to be able to expand and contract independently of the undulation cylinder 25, and is configured to be able to swing the bending / stretching post 27 at a large swing angle. In this manner, the post 37 is inserted and attached so as to be movable in the axial direction in the hollow holder 35 that is swung by the post leveling cylinder 31 and the bending cylinder 33.
[0012]
  The post 37 is formed by assembling a proximal boom 37a, a first intermediate boom 37b, a second intermediate boom 37c, and a distal end boom 37d in a nested manner. The proximal boom 37a is held in the holder 35 so as to be movable in the axial direction, and the first intermediate boom 37b is attached to the proximal boom 37a between the proximal boom 37a and the first intermediate boom 37b shown in FIG. The second intermediate boom 37c and the tip boom 37d can be expanded and contracted by a built-in cylinder (not shown) with respect to the first intermediate boom 37b. The post moving cylinder 38 shown in FIG.Proximal boom 37aThe tip of the rod 38b is pivotally connected to the tip of the first intermediate boom 37b, and the rod 38b is expanded and contracted with respect to the cylinder tube 38a, whereby the first intermediate boom 37b is moved to the base end. The boom 37a can be moved in the axial direction. Here, the post 37 has a four-stage telescopic boom configuration, but it may have a multi-stage telescopic boom configuration such as a two-stage or three-stage telescopic boom.
[0013]
A boom moving cylinder 39 for moving the proximal boom 37a shown in FIG. 1 in the axial direction (vertical direction) with respect to the holder 35 is attached to the side of the holder 35 so as to straddle the holder 35 and the proximal boom 37a. Yes. In this boom moving cylinder 39, the cylinder tube 39a is attached to the holder 35, the tip of the rod 39b is pivotally connected to the rear end of the base end boom 37a, and the rod 39b is expanded and contracted with respect to the cylinder tube 39a. The entire post 37 can be moved in the axial direction with respect to the holder 35.
[0014]
A support arm 41 is provided at the tip of the tip boom 37d so as to be swingable forward and backward and up and down of the vehicle. The support arm 41 is provided between the tip of the tip boom 37d and the side surface of the support arm 41. It is supported so as to extend vertically by a pivoted arm turning cylinder 44. As shown in FIG. 2, a swing mechanism 45 is attached to the tip (lower end) of the support arm 41, and a work table 47 is attached thereto. A platform leveling cylinder 43 is disposed on the support arm 41 shown in FIG. 1, and one end of the platform leveling cylinder 43 is pivotally connected to a swing mechanism 45. Therefore, the work table 47 is supported in a horizontal state via the swing mechanism 45 by the expansion and contraction of the platform leveling cylinder 43. The swing mechanism 45 has a built-in swing motor 46 shown in FIG. 3, and is configured such that when the swing motor 46 is driven, the work table 47 rotates horizontally in a horizontal plane. As a result, the work table 47 can be swung while being supported horizontally.
[0015]
As shown in FIG. 4B, the work table 47 is telescopically movable by combining a base end bucket 47a, an intermediate bucket 47b and a front end bucket 47c in a nested manner. It is configured to expand and contract. A handrail 47d surrounding each periphery is attached to the base end bucket 47a, the intermediate bucket 47b, and the front end bucket 47c of the work table 47. As shown in FIG. 3, the work table 47 includes a work table swing operation device 53 for operating the swing motion of the work table 47 shown in FIG. 4B, and a work table for operating the telescopic motion of the work table 47. The telescopic operation device 55 is provided, and each of these operation devices 53 and 55 has operation levers 53a and 55a that can be tilted in the left-right direction or the front-rear direction. When the operation lever 53a is tilted to one side, the work table 47 shown in FIG. 4A is moved to one side of the work table 53 with respect to the post 37 (upper side in FIG. 4A). The work table 47 is configured to swing to the other side (the lower side of FIG. 4A) with respect to the post 37 when tilted to the other side. When the operation lever 55a is tilted to one side, the work table expansion / contraction operation device 55 expands and the work table 47 shown in FIG. 4A is tilted to the other side. The work table 47 shown is configured to be reduced. 4 is provided with a boom operating device (not shown) for operating the turning movement of the boom 23, the raising / lowering movement and the expansion / contraction movement, the vertical movement of the holder 35, and the expansion / contraction movement of the post 37. .
[0016]
As shown in FIG. 1, the boom 23 for moving the work table 47 is stored in a state where it is lying down in a horizontal direction from the rear side to the front side of the vehicle, and is erected from a substantially central portion of the vehicle body 7. Supported by the boom receiver. Further, the post 37 swings so as to overlap the boom 23 stored on the vehicle body 7, extends in the front-rear direction on the vehicle body 7 in a folded state, is stored in a lying manner, and protrudes from the upper surface of the boom 23. It is supported by a post receiver (not shown). The work bench 47 is stored in a position on the left side of the vehicle with respect to the stored boom 23 and post 37.
[0017]
Outriggers 13 and 14 configured to be movable in the vertical and horizontal directions are provided on the left and right sides of the front and rear of the vehicle body 7. The outriggers 13 and 14 have grounding rollers 13a and 14a at their lower ends, respectively, and when working at a high place, the outriggers 13 and 14 are projected while the front and rear wheels 3 are grounded to ground the grounding rollers 13a and 14a. Thus, the vehicle body 7 is supported. Further, by driving the wheel 3 while supporting the vehicle body 7 as described above, the vehicle can be driven at a low speed and a predetermined height work (such as a bridge inspection work) can be performed. .
[0018]
As shown in FIG. 3, the overfence work vehicle 1 configured in this way prevents the vehicle from falling over due to the swinging and extending movements of the work table 47 shown in FIG. 4B. The fall prevention device 60 is provided. The fall prevention device 60 detects a work table swing angle sensor 61 that detects a swing angle of the work table 47 with respect to the post 37 in the vertical state shown in FIG. In addition to controlling the operation of the swing motor 46 and the telescopic cylinder 49 in accordance with the operation of the work table extension sensor 63, the work table swing operation device 53, and the work table expansion / contraction operation device 55, the work table swing angle sensor 61 and When the controller 65 that restricts the operation of the swing motor 46 and the telescopic cylinder 49 according to the detection value from the work table extension sensor 63 and the operation of at least one of the swing motor 46 and the telescopic cylinder 49 are restricted. And an alarm buzzer 73 for generating a sound.
[0019]
The controller 65 is electrically connected to the work table swing operation device 53 and the work table expansion / contraction operation device 55, and has operation control valves 75 and 76 for controlling the operations of the swing motor 46 and the extension cylinder 49. They are electrically connected via a signal transmission line 77.
[0020]
The controller 65 includes an operation control circuit 79, a work table position calculation circuit 80, a determination circuit 81, and a regulation drive circuit 82. When the operation control circuit 79 receives the operation signals from the work table swing operation device 53 and the work table expansion / contraction operation device 55, the operation control circuit 79 outputs a control signal for controlling the operation of the operation control valves 75 and 76 corresponding thereto. The workbench position calculation circuit 80 corresponds to the detected values from the workbench swing angle sensor 61 and the workbench extension sensor 63 (hereinafter collectively referred to as “workbench position sensors 61, 63”). The tip position of the work table 47 with respect to the post 37 shown in a) is calculated. The determination circuit 81 determines whether or not the tip position of the work table 47 shown in FIG. 4A detected by the work table position sensors 61 and 63 exceeds the allowable movement range H. Here, the allowable movement range H is a movable range of the work table 47 set in advance so that the overturning direction moment acting on the vehicle does not exceed the allowable overturning direction moment.
[0021]
  As shown in FIG. 4 (a), this allowable movement range H is the right allowable line.L1, A range surrounded by the front permissible line L2, the rear permissible line L3, and the left permissible line L4. Here, as shown in FIG. 6, the right tolerance line L <b> 1 is a work table 47 extending in the vehicle front-rear direction by an extension amount X in a substantially right angle direction with respect to the overfence work vehicle 1 extending forward and backward from the post 37 extending vertically. Is a movement locus of the center position of the tip of the work table 47 when the head is swung at an angle θ (in the case of FIG. 4, θ = 15 °), and the front allowable line L2 extends from the post 37 extending vertically. This is a line connecting the tip position of the work table 47 and the end of the right permissible line L1 on the front side of the vehicle when the work table 47 is swung to the front side of the vehicle in a fully contracted state substantially parallel to the vehicle. The rear permissible line L3 is the front end position and the right side of the work table 47 when the work table 47 is swung to the rear side of the vehicle in a fully contracted state substantially parallel to the vehicle extending forward and backward from the vertically extending post 37. The left side allowance line L4 is a line connecting the end of the allowance line L1 on the rear side of the vehicle, and the left allowance line L4 is substantially parallel to the vehicle extending in the front-rear direction from the post 37 extending vertically. This is a line passing through the left end of the work table 47 when the head is swung. In addition, you may make it change the right side tolerance line L1, the front side tolerance line L2, and the rear side tolerance line L3 mentioned above according to the turning position of the boom 23 shown in FIG.
[0022]
Here, the allowable movement range H is considered. As described above, the allowable movement range H is a movable range of the work table 47 such that the overturning direction moment acting on the vehicle does not exceed the allowable overturning direction moment, but on the vehicle front side with respect to the swivel base 21 shown in FIG. Since the outrigger 13 is provided, as shown in FIG. 5, even if the work table 47 having the extension amount X is swung to the front side of the vehicle, the center of gravity G of the work table 47 is higher than that of the outrigger 13 on the front side of the vehicle. Since the vehicle does not move greatly to the front side and the weight of the vehicle itself is large, there is no possibility of the vehicle falling over to the front side. Further, when the outrigger 14 is disposed on the rear side of the vehicle shown in FIG. 6 and the outrigger 14 is disposed on the rear side of the vehicle body with respect to the turning center position of the turntable 21, the rear permissible line is provided. Even if L3 is moved to a position having a predetermined distance on the rear side of the vehicle, there is no possibility that the vehicle falls to the rear side. For this reason, it is considered that the allowable movement range H shown in FIG. 5 may be a range H ′ indicated by a broken line.
[0023]
However, as shown in FIG. 6, when the work table 47 extends in the same direction as the extending direction of the boom 23, a bending moment acts on the distal end portion of the boom 23. Further, when the work table 47 in the fully contracted state is positioned in a direction perpendicular to the extending direction of the boom 23, a torsional moment acts on the tip end portion of the boom 23. Further, if the work table 47 swings or extends in these states, the bending moment or the torsional moment acting on the tip of the boom 23 is further increased, and the boom 23 may be damaged. Therefore, the allowable movement range H is set to a range as shown in FIG. 4A in consideration of the strength of the boom 23 in addition to the possibility of the vehicle falling.
[0024]
In addition, since the boom 23 can turn, undulate and extend and retract, when the boom 23 is driven, there is a risk that the overturning direction moment acting on the vehicle increases and the vehicle falls. For this reason, the over fence work vehicle 1 is provided with a work range restricting device (not shown) related to the boom 23 according to the overturn prevention device 60 shown in FIG. The boom 23 is configured to be restricted from operating beyond a set allowable work range (not shown).
[0025]
Next, the operation of the overturn prevention device 60 according to the present invention will be described. FIG. 4B shows an example of the work by the overfence work vehicle 1 and shows a state where the work table 47 is moved below the bridge B. As shown in the figure, in order to perform work at a work position below the bridge B, first, the vehicle is substantially parallel to the fence F on the bridge B above the work position, and at a predetermined distance from the fence F to the inside. Is moved to a position having Subsequently, the outriggers 13 and 14 on the front and rear sides of the vehicle disposed on the fence F side are projected to support the vehicle while the wheels 3 remain in a grounded state. Subsequently, a boom operating device (not shown) is operated, the boom 23 swings, undulates and extends, the holder 35 swings up and down to bring the post 37 into a vertical state, and the post 37 extends. Further, the work table swing operation device 53 shown in FIG. 3 provided on the work table 47 is operated, and the work table 47 in the fully contracted state swings and moves in a state of extending to the vehicle side with respect to the post 37. To do.
[0026]
  Here, simultaneously with the operation of the boom 23, the work range restricting device (not shown) of the boom 23 and the overturn prevention device 60 shown in FIG. 3 of the work table 47 are operated, and the tip of the boom 23 is moved by the work range restricting device. The operation of the boom 23 exceeding the work regulation range (not shown) is regulated, and the work table 47 whose tip end portion exceeds the allowable movement range H shown in FIG. 4A by the fall prevention device 60 shown in FIG. Regulate the swing of the head. More specifically, when the boom 23 is operated and the post 37 is in a vertical state (the vertical state detection of the post 37 is performed by a vertical determination unit of a work range regulating device (not shown), the hoisting cylinder 25, the post leveling cylinder 31, and the bending / extending cylinder 33). 3), as shown in FIG. 3, the workbench position calculation circuit 80 uses the post 37 shown in FIG. 4 (b) based on the detection values from the workbench position sensors 61 and 63. The tip position of the tip portion of the work table 47 is calculated. Subsequently, the determination circuit 81 determines whether or not the calculated tip position is within the allowable movement range H shown in FIG. 4A. If the tip position exceeds the allowable movement range H, the determination circuit 81 is determined. Activates the regulation drive circuit 82, and the regulation drive circuit 82 does not transmit the control signal sent from the operation control circuit 79 to the operation control valve 75 that controls the operation of the oscillation motor 46. Thus, the signal transmission line 77 is cut off. Also,Regulatory driveWhen the circuit 82 receives a signal from the determination circuit 81 that the tip position exceeds the allowable movement range H, the circuit buzzes the alarm buzzer 73.
[0027]
Therefore, in the process of moving the work table 47 to the work position, the tip of the boom 23 does not exceed the work regulation range (not shown), and the work table 47 does not exceed the allowable movement range H. As a result, the work table 47 can be moved from the storage position of the vehicle to the work position in a state where there is no possibility that the vehicle will fall down.
[0028]
  Next, a case where the work table 47 moved to the work position swings and extends will be described. As shown in FIGS. 4A and 4B, first, work is performed by the work table extension / contraction operation device 55 shown in FIG. A case where the table 47 is operated to extend will be described. When the work table expansion / contraction operation device 55 is operated as described above, the operation control circuit 79 shown in FIG. 3 converts the operation signal sent from the work table expansion / contraction operation device 55 into an operation control signal, and the operation control signal expands. The operation of the operation control valve 76 that controls the operation of the cylinder 49 is controlled. As a result, the extension cylinder 49 extends and the work table 47 extends. Here, when the extension operation by the work table extension / contraction operation device 55 is continued, the extension amount of the work table 47 increases, and the tip of the work table 47 exceeds the right allowable line L1 of the allowable work range H. And However, if the work table 47 tries to exceed the right allowable line L1 of the allowable work range H, as shown in FIG.Regulatory driveCircuit 82 is activated and thisRegulatory driveThe circuit 82 cuts off the signal transmission line 77 so that the control signal of the expansion cylinder 49 sent from the operation control circuit 79 is not transmitted to the operation control valve 76. Also,Regulatory drivecircuit82Sounds the alarm buzzer 73. For this reason, it is possible to prevent an excessive bending moment acting on the boom 23 due to the extension movement of the work table 47 and to prevent the boom 23 from being damaged.
[0029]
  Further, the work table 47 is moved to the vehicle in a state where the front end portion of the work table 47 is extended to a position in front of the right allowable line L1 of the allowable work range H (a position where the extension amount of the work table 47 is X). When the head is swung to the front side, the tip of the work table 47 tends to exceed the front allowable line L2 of the allowable work range H. However, as described above, the tip of the work table 47 is shown in FIG. 3 so as to exceed the front allowable line L2.Regulatory driveCircuit 82 is activated and thisRegulatory driveThe circuit 82 blocks the signal transmission line 77 so that the control signal of the swing motor 46 sent from the operation control circuit 79 is not transmitted to the operation control valve 75,Regulatory driveThe circuit 82 sounds the alarm buzzer 73. For this reason, the bending moment and the torsional moment that act on the boom 23 due to the swinging motion of the work table 47 can be prevented, and the situation in which the boom 23 is damaged can be prevented. Further, when the work table 47 is swung to the rear side of the vehicle, if the tip of the work table 47 tries to exceed the rear allowable line L3 of the allowable work range H, as shown in FIG.Regulatory driveThe circuit 82 operates to regulate the operation of the swing motor 46,Regulatory driveThe circuit 82 sounds the alarm buzzer 73. For this reason, it is possible to prevent the vehicle 23 from falling to the rear side due to an increase in bending moment and torsional moment acting on the boom 23 due to the swing of the work table 47, and to prevent the boom 23 from being damaged. be able to.
[0030]
  FIG. 3 also shows the case where the work table 47 is extended and moved in a state where the work table 47 is fully contracted and oriented in the same direction as the front-rear direction of the vehicle.Regulatory driveThe circuit 82 is activated and the operation of the extension cylinder 49 is restricted;Regulatory driveCircuit 82 sounds alarm buzzer 73. Therefore, it is possible to prevent the boom 23 from being damaged due to an increase in the torsional moment acting on the boom 23 due to the extension movement of the work table 47, and the work table 47 is swung to the rear side of the vehicle. In this case, it is possible to prevent the vehicle from falling further toward the rear side.
[0031]
In this manner, the allowable work range H of the work table 47 is set separately from the work control range (not shown) of the boom 23, and the swinging and extending movements of the work table 47 exceeding the allowable work range H are restricted. By doing so, it is possible to prevent the vehicle from falling over due to an increase in the falling direction moment acting on the vehicle as the work table 47 extends and swings, and to prevent the boom 23 from being damaged. be able to.
[0032]
【The invention's effect】
  According to the fall prevention device of the present invention, the work table can swing and extend and contract in the horizontal plane at the tip of the vertical post, and the extension amount and the swing angle of the work table.Detected fromTip position of workbenchButActuation of the swing actuator and telescopic actuator that causes the work table to move in a direction exceeding the allowable movement range if the allowable movement range is exceededIs regulated. For this reasonEven if the work table moves horizontally with respect to the vertical post and the overturning moment acting on the vehicle increases, the overturning moment does not exceed the allowable overturning moment, and the vehicle can be prevented from falling over. be able to. In addition, even if the moment generated by the horizontal movement of the platform acts as a bending moment or torsional moment on the boom, the allowable movement range does not damage the boom.Is setThus, it is possible to prevent the boom from being damaged by the horizontal movement of the work table.
[Brief description of the drawings]
FIG. 1 is a perspective view of an overfence work vehicle equipped with a fall prevention device according to an embodiment of the present invention.
FIG. 2 is a perspective view when the overfence work vehicle equipped with the overturn prevention device according to the embodiment of the present invention is in a working state.
FIG. 3 is a block diagram of a fall prevention device according to an embodiment of the present invention.
FIG. 4 shows an overfence work vehicle for explaining the operation of the overturn prevention device according to the embodiment of the present invention. FIG. 4 (a) is a plan view of a work table that moves within an allowable movement range; FIG. 4B is a rear side view when the overfence work vehicle is in a working state.
FIG. 5 is a plan view for explaining an allowable work range in one embodiment of the present invention.
FIG. 6 is a plan view of an overfence work vehicle for explaining the operation of the overturn prevention device according to the embodiment of the present invention.
[Explanation of symbols]
1 Overfence work vehicle (aerial work vehicle)
7 Body (vehicle)
23 Boom
37 posts (vertical posts)
46 Swing motor (swing actuator)
47 workbench
49 Extension cylinder (extension actuator)
60 Fall prevention device
61 Work table swing angle sensor (work table position detection means)
63 Work table extension sensor (work table position detecting means)
81 determination circuit (workbench position determination means)
82 Regulation drive circuit (operation regulation means)
H Allowable movement range

Claims (3)

A boom provided to the vehicle so as to be capable of turning and raising and lowering; a vertical post provided at the distal end portion of the boom so as to be swingable up and down and supported substantially vertically regardless of the raising and lowering angle of the boom; and a base end An aerial work vehicle having a workbench provided with a workbench that is swingable in a horizontal plane at the front end of the vertical post and whose front end side is configured to expand and contract in the horizontal direction with respect to the vertical post. The fall prevention device of
A swing actuator for swinging the work table;
A telescopic actuator for expanding and contracting the work table;
A work table position detecting means for detecting a tip position of the work table with respect to the vertical post from a swing angle position of the work table with respect to the vertical post and an extension amount of the work table with respect to the vertical post;
Work to determine whether the tip position of the workbench detected by the workbench position detection means exceeds a preset allowable movement range in consideration of an allowable fall direction moment and a moment acting on the boom. Table position determination means;
When the work table position determining means determines that the tip position of the work table exceeds the allowable movement range, the operation of the swing actuator and the telescopic actuator in a direction in which the work table exceeds the allowable movement range is performed. An apparatus for preventing overturning of an aerial work vehicle, characterized in that it comprises an operation restricting means for restricting. The vertical post is provided at the front end of the boom so as to be vertically movable,
2. The structure according to claim 1, wherein the vertical post is extended downward and the work table is positioned below the vehicle so that the work table can swing and expand and contract. The fall prevention device of the aerial work vehicle described. 2. The boom allowable position in which the vertical post is located on the side of the vehicle, wherein the allowable movement range is set narrower in the front-rear direction of the vehicle than in the vehicle width direction of the vehicle. 2. A device for preventing overturning of an aerial work vehicle described in 2.

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