JP2557659Y2 - Lifter in aerial work vehicle - Google Patents

Description

[Detailed description of the invention]

In this invention, a telescopic boom is mounted on a bogie so that it can be swiveled and raised, and a work stage on which a worker rides is mounted on the end of the boom. The present invention relates to an aerial work vehicle equipped with a lifter that reciprocates between and. In particular, a drive means for the lifter that moves back and forth between the work stage and the bogie along the boom, and a work floor level for keeping the work floor surface of the lifter horizontal regardless of the boom elevation angle. The present invention relates to an aerial work vehicle in which a holding mechanism and a safety device for a lifter are further assembled.

[0002]

2. Description of the Related Art There are known so-called high-altitude work vehicles used when performing high-altitude work such as construction work for high-rise building structures and maintenance and repair work for various other structures. For example, a boom that can be swiveled and raised on a trolley is provided, and at the tip of this boom is equipped with a gondola where the operator gets in, or a work floor that incorporates a hydraulic operation cylinder on the trolley and lifts it This is the case with tower-type work vehicles.

[0003] However, in these conventional aerial work vehicles, the gondola or work floor is lifted up to a desired height position, and once the work is started, the operator can easily get on and off during the work. There was a difficult disadvantage. For example, if you have forgotten to bring in tools or the size of the replacement part does not fit,
There was a drawback that it was difficult to get off easily. In other words, there has been a problem that it is necessary to shorten the boom that has been lifted up or to lower the work floor. This inconvenience is greater as the height is higher, and not only is it cumbersome, but also has the disadvantage of causing a time loss.

Therefore, as a means for eliminating such inconvenience and time loss, as shown in FIG. 8, a work stage 3 mounted on a tip end of a boom 2 mounted on a carriage 1 and a carriage 1 are provided. An aerial work vehicle with a lifter has been developed which is equipped with a lifter 4 that moves up and down along the boom 2 and is configured to be able to get on and off the work stage 3 using the lifter 4.

[0005] However, the lifting and lowering operation of the lifter 4 in the aerial work vehicle equipped with the lifter generally has the following configuration. That is, FIG.
As shown in FIG. 1, a winch 5 is set on a carriage 1 and a tip 6a of a wire rope 6 of the winch 5 is connected to a lifter 4 via a sheave 7 provided at a tip of the boom 2. , The wire rope 6 is wound up, and the lifter 4 is raised (along arrow) along the boom 2. When the lifter 4 is to be lowered, the lifter 4 is lowered solely by using its own weight.

[0006]

Therefore, the conventional aerial work vehicle with a lifter has the following problems. (1) When the operator gets on the work stage 3, there is no particular problem. However, when the operator gets off, that is, when the lifter 4 is lowered, if the elevation angle of the boom 2 is gentle,
Lifter 4 does not descend smoothly. Therefore, it is necessary to incorporate a counterweight and an auxiliary means for performing a special descending operation into the lifter 4. (2) The lifter 4 is assembled so as to be able to move up and down along a guide rail 2a simply attached to the boom 2. Therefore, when the elevation angle of the boom 2 becomes large or becomes gentle, the work floor surface of the lifter 4 changes accordingly. That is, the work floor is inclined. As a result, there was a disadvantage that the foothold of the worker who got on the lifter 4 became unstable. (3) Safety measures in the event that trouble occurs in the wire work of the wire rope 6, especially when the lifter 4 does not move in the middle of the boom 2, and an operator riding on the lifter 4 Safe evacuation measures were inadequate. In such a case, conventionally, the boom 2 was tilted down, and the height position of the lifter 4 was lowered to descend.

In any case, in the conventional aerial work vehicle with a lifter, there is a problem in the smooth and safe lifting operation of the lifter itself. The present invention has been devised for the purpose of solving such difficulties and providing a lifter for an aerial work vehicle with improved lifter operability, safety, and functionality.

[0008]

According to the present invention, as a means for achieving the above object, first, two winches driven by a hydraulic motor are installed on a bogie as lifting / lowering driving means for a lifter. The tip of the wire rope of one winch is connected to the front end of the lifter via a sheave provided at the tip of the boom, and the tip of the wire rope of another winch is provided on the bogie. And connected to the rear end of the lifter via a sheave.

The hydraulic motors of the two winches are connected in parallel to hydraulic power units mounted on the respective trucks via directional control valves. Further, the hydraulic motor inlet and outlet sides of each hydraulic motor are provided. In between,
A bypass circuit that is normally open is provided, and a brake valve including a relief valve is provided in the bypass circuit.

[0010] Further, the lifter is constructed by combining a movable gantry moving along a guide rail attached to the boom and a work floor as follows. First, the movable gantry was configured to move across right and left guide rails attached to the boom. The work floor was mounted on the movable gantry such that the front end was pivotally supported on the front end of the movable gantry with a support shaft, and the rear end could be tilted up and down with the support shaft as a fulcrum. Next, as a horizontal holding mechanism for holding the floor surface of the work floor horizontally, a hydraulic power unit was mounted on a movable gantry, and a horizontal detector was attached to the work floor.

Then, a hydraulically operated operating cylinder is interposed between the rear end of the movable gantry and the work floor, and this operating cylinder is connected to a hydraulic power unit mounted on the movable gantry via a direction switching control valve. According to the present invention, it is possible to control the direction switching control valve of the operation cylinder based on the detection signal of the horizontal detector attached to the work floor, so that the work floor of the lifter can be always kept horizontal regardless of the elevation angle of the boom. Configured.

In the safety device for the lifter, a wire rope connected to the front end of the lifter is linked to an overload meter including a load cell attached to the lifter, and further connected to a gravity hook pivotally supported by the lifter. A load based on the tension generated in the wire rope is set in advance on the overload meter interposed in the wire rope, and when the tension exceeds the set load or becomes zero, the overload meter is broken and the gravity is cut off. The tip of the hook is dropped, and the tip is engaged with a horizontal rail provided at a constant pitch on the guide rail of the lifter. That is, the tip of the gravity hook falls and engages with the guide rail, so that the movement of the lifter itself is locked to the guide rail and stopped.

[0013]

Since the present invention is constructed as described above, one of the hydraulic motors for driving two winches, in other words, by connecting the tip of the wire rope to the front end of the lifter. The winch-side hydraulic motor is operated by opening the direction switching control valve. The lifter will then be lifted along the boom. At that time, the winch hydraulic motor having the wire rope connected to the rear end of the lifter rotates in the reverse direction because the wire rope is pulled out. By the way, since a bypass circuit is connected to the inlet and outlet sides of the hydraulic oil of the counter-rotating hydraulic motor and a brake valve including a relief valve is incorporated, the hydraulic motor has a braking action. As a result, the wire rope is pulled out under tension, and the lifter is raised in a stable state. Conversely, when the lifter is lowered, the hydraulic motor of the winch operated at the time of lifting also has a braking action. Therefore, the wire rope is maintained in a tensioned state when the lifter is lifted or lowered, and the lifting operation of the lifter is smoothly and stably maintained.

Further, even if the boom is raised and the inclination angle of the boom fluctuates, the work floor of the lifter switches the direction switching control valve in accordance with a signal of a horizontal detector mounted on the work floor,
Operate the operation cylinder to keep the work floor horizontal. Also, in the unlikely event that the tension of the wire rope connected to the lifter exceeds a certain value, or in other words, the lifter derails from the guide rail provided along the boom and stops moving, or the wire rope When it breaks and the tension goes to zero, the gravity hook automatically activates. As a result, the lifter is stopped at the position on the boom side. That is, the crash of the lifter is prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in the drawings. First, FIG. 1 is a conceptual diagram showing a drive mechanism of a lifter 40 that moves up and down along a boom 20. Reference numeral 30 denotes a work stage provided at the tip of the boom 20. Reference numeral 50u denotes a hydraulic motor for driving a winch installed on a trolley, which is a hoist hydraulic motor for raising the lifter 40 along the boom 20. Reference numeral 50d denotes a lowering hydraulic motor for lowering the motor.

Numeral 60 denotes each hoisting hydraulic motor 5
0u and the wire rope of the hydraulic motor 50d for lowering. The tip portion 60a of the wire rope 60 on the hydraulic motor 50u side for winding is attached to the front end portion of the lifter 40,
On the right side in FIG. 1, on the other hand, the distal end portion 60 b of the wire rope 60 on the side of the hydraulic motor for lowering 50 d is connected to the lifter 40.
At the rear end, that is, on the left side. Reference numeral 61a denotes a sheave provided at the tip of the boom 40, and 61b denotes a sheave provided on the bogie. Therefore, when raising the lifter 40 in this embodiment, the lifting hydraulic motor 50u may be driven. Conversely, when lowering the lifter 40, the lowering hydraulic motor 50d
Should be driven.

FIG. 2 is a control circuit diagram of a hydraulic motor for driving the lifting hydraulic motor 50u and the lowering hydraulic motor 50d. As shown, the hydraulic motor for winding 5
0u and the hydraulic motor 50d for lowering are connected to the hydraulic power unit PW mounted on the trolley, respectively, by the direction switching control valve 7.
Connected in parallel via Ou and 70d. Further, bypass circuits 71u and 71d are connected to the hydraulic fluid inlet and outlet sides of the hydraulic motors 50u and 50d, respectively.
1u and 71d have direction switching control valves 72u and 72d.
d, and brake valves 73u and 73d composed of relief valves are provided to maintain a normally open state. In the embodiment, the direction switching control valves 70u and 7u
0d, and the direction switching control valves 72u and 72d provided in the bypass circuits 71u and 71d are each configured by an automatic control system using a solenoid operated valve.

Therefore, for example, when the lifter 40 is raised, the left direction switching control valve 7 in the hydraulic circuit is required.
0u is opened, and the winding hydraulic motor 50u is rotationally driven. Then, with the rotation of the hoist hydraulic motor 50u, the lifter 40 is pulled up along the boom 20, as understood from the configuration shown in FIG. At the same time, the lowering hydraulic motor 50d is rotated in a direction opposite to the rotation direction of the lifting hydraulic motor 50u. This is because the lifting of the lifter 40 causes the wire rope 60 to move from the winch on the hydraulic motor 50 d for lowering.
Is forcibly withdrawn.

However, a bypass circuit 7 having a brake valve 73d formed of a relief valve is provided between the hydraulic oil inlet motor 50d and the hydraulic oil motor 50d.
1d is connected, the lowering hydraulic motor 50
d will be given a braking action. As a result, the drawn wire rope 60 is always kept in a tensioned state.

Conversely, when lowering the lifter 40, the right direction switching control valve 70d shown in FIG. 2 is opened, and the lowering hydraulic motor 50d is driven to rotate. The braking force acts on the rotation of the motor, and the wire rope 60 is pulled out under tension. The operation of the direction switching control valves 70u and 70d is as follows.
Although not shown in the drawing, the operation is performed through operation panels installed on the truck and the work stage 30 side.

Next, the lifter 40 is constituted as shown in FIG.
First, the left and right guide rails 21 provided along the boom 20
The movable gantry 41 was movably mounted on (21). That is, guide rollers 42 are pivotally supported on both the front, rear, left and right sides of the movable base 41, and the guide rollers 42, 42 are slidably engaged with the guide rails 21 (21) and mounted so as to straddle the boom 20. . A support shaft 4 is attached to the front end of the work floor 43, and the left end in FIG.
4 and was mounted on a movable gantry 41 so that the rear end could be tilted up and down.

The horizontal holding mechanism of the work floor 43 constituting the lifter 40 is constructed as follows. First, a hydraulic power unit 45 was mounted on the movable base 41, and a horizontal detector 46 was mounted on the work floor 43 side. Next, between the front end of the movable base 41 and the work floor 43,
A hydraulic operation cylinder 47 was provided. The work floor 43 is provided with a handrail 48 for safety.

Further, as shown in FIG. 4, a hydraulic power unit 45 on the movable gantry 1 is connected to the hydraulic operating cylinder 47 via a solenoid-type directional control valve 49, and the directional control valve 49 is connected to the horizontal detection unit. The vessel 46 was connected.
That is, the direction switching control valve 49 operates based on the detection signal of the horizontal detector 46, and the hydraulic operation cylinder 47 operates based on the operation, and as a result, the work floor 43 is always maintained in a horizontal state. And In the embodiment, as the horizontal detector 46, a pendulum-shaped movable sensor 46a is provided on the work floor 43 side as shown in FIG.
a is a left and right fixed sensor 46 also provided on the work floor 43 side.
When it deviates in either direction b or 46b, a control signal is automatically transmitted, that is, a detection signal is transmitted, and the hydraulic operation cylinder 47 is operated via the direction switching control valve 49.

FIG. 5 shows the lifter 40 which is moved up and down.
FIG. 6 is a side view showing a configuration of the safety device of FIG. First, the lifter 40 itself includes the movable gantry 41 and the working floor 43 as described above. The movable gantry is formed of a frame having a quadrangular shape as shown in the figure, and the guide rollers 42 are pivotally supported on both sides in the longitudinal direction, and the guide rollers 42 on both sides are indicated by imaginary lines. , Guide rail 2 provided in the longitudinal direction of boom 20
1 and 21 so as to be able to run freely. Hoisting hydraulic motor 5 for raising lifter 40 itself
As described above, the wire rope 60 on the 0u side has its distal end 60a connected to the front end of the movable gantry 41 constituting the lifter 40, to the right as shown in FIGS. Wire rope 6 on hydraulic motor 50d for lowering side
The leading end portions 60b of 0 are connected to the left side, respectively.

As a safety device of the lifter 40,
An overload meter 62 composed of a load cell and two gravity hooks 63 and 63 were attached to the movable base 41 of the lifter 40 so as to be tiltable. That is, it was pivoted. Next, the operating body 62a of the overload meter 62
And the gravity hook 63 on the left side are connected by a wire 64, and are connected such that the tip 63a of the gravity hook 63 is held in a state of protruding upward on the movable gantry 41 as shown in FIG.

The other gravity hook 63, that is, the right gravity hook 63, was connected to the wire 64 so that the tip 63a was held upward, similarly to the left gravity hook 63. The tip 60a of the wire rope 60 on the winding hydraulic motor 50u side.
Was connected to the front end of the movable base 41 via a lever-like lever 66 as shown in FIG. First, the distal end portion 60a was connected to an intermediate portion of a lever-like lever 66, and one free end portion 66a of the lever 66 was connected to the overload meter 62. The other free end 66 b is connected to the opposite left-side gravity hook 63 via a wire 64 and a sheave 65. When the tension of the wire rope 60 pre-loaded by the lifter 40 reaches a certain value or more, or when the wire rope 60 is cut off for some reason, the overload meter 62 displays the overload meter 6.
The two operating bodies 62a are released, that is, are broken, and the leading ends 63 of the left and right gravity hooks 63 and 63
Each of a and 63a was configured to be tilted and dropped by its own weight.

The left and right gravity hooks 6
When the tip portions 63a and 63a of 3 and 63 are tilted and dropped, the respective tip portions 63a and 63a are fixed to guide rails 21 and 21 attached to both sides of the boom 20 at a constant pitch, as shown in FIGS. It was configured to be locked to any of the horizontal rails 22.
That is, the horizontal rails 22 are attached to the guide rails 21 and 21 on both sides at a predetermined pitch in advance, and the left and right gravity hooks 63 are locked to this. Then, if an excessive load is applied to the wire rope 60 on the side of the hydraulic motor 50u for lifting, which lifts the lifter 40, or if the wire rope 60 is cut, the lifter 40 will move to the overload meter 62 and the gravity at that time. The safety device including the hooks 63, 63 is operated to be locked on the guide rail 21 side fixed to the boom 20, so that it does not fall down. FIG. 7 is a side view showing a state where the gravity hooks 63 and 63 are locked on the horizontal rail 22 of the guide rail 21.

[0028]

[Effects of the Invention] The present invention is constructed as described in the above embodiments, and therefore the following functions and effects can be exhibited as an aerial work vehicle with a lifter. (1) In both cases of lifting and lowering the lifter, the lifting operation is performed by lifting or lowering by a hydraulic winch, so that the lifting operation can be performed without being affected by the elevation angle of the boom as in the related art. For example, the lifter can be operated even when the boom is in a horizontal state. as a result,
The use of this lifter has made it possible to work at relatively flat heights. In any case, the lifter can be moved smoothly and safely, so that the operator can easily and quickly get on and off the work stage at the end of the boom, and can improve the efficiency of work at high places. (2) Since the work floor of the lifter is always kept horizontal regardless of the boom lowering angle, when the operator gets on and off the vehicle, it is safe and stable work can be performed. (3) If an unreasonable load is applied to the wire rope that moves the lifter up or down, or if it is cut, the safety device consisting of the overload meter and the gravity hook will be activated immediately, and the crash of the lifter itself may occur. Is prevented. (4) Since the gravity hook constituting the safety device is configured to be locked to a horizontal rail provided at a constant pitch on a guide rail for guiding the lifter, the lifter stopped in the middle of the boom due to an accident. In such a case, the worker riding on the lifter can use the horizontal rail of the guide rail laid at the predetermined pitch as an evacuation ladder in an emergency, and get down on the bogie.

As described above, the aerial work vehicle with a lifter according to the present invention is constructed so that the lifter itself can be moved even when the boom is horizontal, and the lifter horizontal holding means and the safety device are incorporated. As a result, the efficiency, functionality, and safety of working at heights can be improved, and the utility as a workplace at high places, which has never been achieved before, can be exhibited.

[0030]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a lifter driving device for a lifter according to the present invention.

FIG. 2 is a control circuit diagram of a hydraulic motor included in a lift drive device of the lifter.

FIG. 3 is a side view showing a configuration of a lifter.

FIG. 4 is a hydraulic control circuit diagram showing a horizontal holding mechanism of the lifter.

FIG. 5 is a plan view showing a configuration of a safety device of the lifter.

FIG. 6 is a side view of FIG. 5;

FIG. 7 is a side view showing the relationship between the gravity hook and the guide rail when the gravity hook in the lifter safety device operates and the lifter is stopped in the middle of the boom.

FIG. 8 is a side view showing a schematic configuration of a conventional aerial work vehicle with a lifter.

[Explanation of symbols]

 20 boom 21 guide rail 22 side rail 30 work stage 40 lifter 41 moving base 42 guide roller 43 work floor 44 support shaft 45 hydraulic power unit 46 … Horizontal detector 47… Hydraulic operation cylinder 48… Handrail 49… Direction switching control valve 50u… Lifter lifting hydraulic motor 50d… Lifter lowering hydraulic motor 60… Wire rope 61a, 61b ... Sheave 62 ... Overload meter 63 ... Gravity hook 64 ... Wire 65 ... Sheave 66 ... Lever lever PW ... Hydraulic power unit 70u, 70d ... Direction switching control valve 71u, 71d ... Bypass circuit 72u, 72d: Switching control valve 73u, 73d: Brake valve

Claims (3)

(57) [Scope of request for utility model registration] A telescopic boom is mounted on a bogie so that it can be swiveled and raised, a work stage is mounted at the tip of the boom, and the boom is equipped with a lifter that can move up and down along the boom. In the aerial work vehicle, two winches driven by a hydraulic motor are installed on the bogie, and the tip of a wire rope of one winch is connected to a lifter via a sheave provided at the tip of the boom. The leading end of the wire rope of the other winch is connected to the rear end of the lifter via a sheave provided on the truck, and the hydraulic motors of the two winches are connected to the truck. Connected in parallel to the equipped hydraulic power units via respective directional control valves,
A normally open bypass circuit is provided between the hydraulic oil inlet and outlet of each hydraulic motor, and the bypass circuit is provided with a brake valve comprising a relief valve. Lifter in work vehicle. 2. The lifter includes a movable platform that moves along a guide rail attached to a boom, and a work floor. A hydraulic power unit is mounted on the movable platform, and the work floor has a floor. Attach the horizontal detector of the surface,
The front end of the work floor is pivotally supported on the front end of the movable gantry with a support shaft, and a hydraulically operated operating cylinder is interposed between the rear end of the movable gantry and the work floor. A lifter working floor connected to a hydraulic power unit mounted on a gantry via a direction switching control valve, and switching control of the direction switching control valve of the operating cylinder based on a detection signal of a horizontal detector assembled to the work floor. The lifter according to claim 1, further comprising a horizontal holding mechanism. 3. The front end of the wire rope connected to the front end of the lifter is connected via an overload meter assembled to the lifter, and the overload meter is further connected to a gravity hook pivotally supported by the lifter. Then, when the tension of the wire rope becomes equal to or more than the set load previously set in the overload meter or becomes zero, the overload meter is activated, and the gravity hook is engaged with the horizontal rail provided on the guide rail of the lifter at a constant pitch. The lifter according to claim 1, further comprising a safety device configured to stop and stop engagement of the lifter on the guide rail.