JPH031240B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an elevating and lowering stop device for an aerial work vehicle that uses an elevating device to lift a work platform on which a worker is seated and performs work at heights. The present invention relates to a lifting stop device that emergencyly stops lifting when an object collides with the object.

This type of aerial work vehicle is used for various types of work at high places, and among these, work is often performed at high places close to the ceiling of relatively narrow spaces with ceilings, such as tunnels and roads. . In this case, the worker on the workbench climbs up to the target work place while operating the control box himself, but at this time, he must be careful when working, such as checking the stretch of the spray hose. Sometimes. For this reason, the worker may neglect to perform the ascending operation while checking the safety above his/her head, and as a result, the worker's head may end up hitting an obstacle such as the ceiling of the tunnel due to the ascending height being too high. At this time, if you stop the machine immediately, it will not cause any serious problems, but if such a process is delayed or impossible, it may result in serious personal injury.

The present invention assumes such unforeseen accidents caused by obstacles above a worker's head, and has developed an elevated platform that protects the worker and prevents damage to the work vehicle itself in the event of accidental collision with such an obstacle. The purpose of the present invention is to provide a lifting/lowering stop device for a work vehicle.

For this purpose, the configuration of the present invention takes into consideration that the helmet on the worker's head is the highest point on the worker's head, and a pressure-sensitive switch means is attached to the helmet to prevent the helmet from colliding with an overhead obstacle. In such a case, the operation signal of the switch means immediately shuts off the hydraulic circuit for lifting and lowering, and the lifting and lowering of the workbench is automatically brought to an emergency stop.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the entire structure of this embodiment. Reference numeral 1 denotes a pedestal. Wheels 2 are pivotally supported on each of the four sides of the pedestal 1, and a loose rotation table 3 is fixed to the upper center surface of the pedestal 1. There is. A car body 4 housing an engine, a hydraulic system, etc. is mounted on the swivel table 3 so as to be rotatable in the horizontal direction, and a pair of triangular shaft support pieces 5 are fixed to the upper surface of the car body 4. A lower boom 6 in the form of a long and narrow pipe with a hollow interior is connected to the apex of the shaft support piece 5 by a pin 7, and the lower boom 6 is pivoted vertically by the pin 7. It is supported. An elongated, hollow middle boom 8 is telescopically inserted into the lower boom 6, and an upper boom 9, which is hollow inside, is telescopically inserted into the middle boom 8.
8 and 9 can be expanded and contracted in length by hydraulic cylinders provided inside. This boom 6, 8,
9 forms a boom body 16. A rectangular workbench 10 on which a worker rides is connected to the tip of the upper boom 9 by a pin 11, and a correction hydraulic cylinder is installed between the upper boom 9 and the workbench 10 to correct the posture. 12 is interposed therebetween, and a control box 13 is attached to the upper part of the workbench 10. Further, a hydraulic cylinder 14 for elevation is interposed between the vehicle body 4 and the lower boom 6, and the lower boom 6 and the hydraulic cylinder 14 are connected by a pin 15.

In FIG. 2, the telescopic mechanism of the boom body 16 will be explained. A cylinder body 18 of a single telescopic hydraulic cylinder 17 provided at the center of the boom body 16 is fixed to the bottom 19 of the lower boom 6, and the piston rod 20 is connected to the bottom of the middle boom 8 via a connecting member 21. In addition, the lower boom 6
One end of a chain 23 is fixed to the tip of the middle boom 8 by a support piece 22, and this chain 23 meshes with a gear 24 rotatably attached to the tip of the middle boom 8. and is connected to the bottom of the upper boom 9. When the piston rod 20 of the hydraulic cylinder 17 extends and projects the middle boom 8, the pull-out action of the chain 23 causes the upper boom 9 to simultaneously extend in the same stroke; conversely, when the piston rod 20 contracts, the pull-out action of the chain 23 causes the middle and upper booms to move forward. Booms 8 and 9 are retracted simultaneously with the same stroke. In this way, among the three stages of booms 6, 8, and 9, the upper stage booms 8 and 9 extend and contract in synchronization with the same stroke by the extension and contraction of the single hydraulic cylinder 17.

FIG. 3 shows a helmet for a worker according to this embodiment, in which pressure-sensitive strip-shaped switch means 26 are attached to the outside of the helmet 25 in a radial and annular manner over the entire area around the apex. Switch means 26
As shown in FIG.
9 and 30 are arranged facing each other and separated from each other, and a connection 27 from this switch means 26 is connected to the control box 13 on the workbench side.

Furthermore, in FIG. 4, the hydraulic circuit of each hydraulic cylinder will be explained.
A drain oil passage 35 to the hydraulic cylinder 4 communicates with an emergency stop solenoid valve 36, and oil passages 37 and 38 from this solenoid valve 36 communicate with one and the other of the hydraulic cylinders 17 via a manual switching valve 39 for expansion and contraction. . Also,
Oil passages 40 and 41 branching from the oil passages 37 and 38 communicate with one and the other of the hydraulic cylinders 14 and 12 via a manual switching valve 42 for elevation and correction. The switching means 26 is connected to a solenoid 44 of the solenoid valve 36 via a control circuit 43 so as to be automatically switched.

Next, the operation of this embodiment will be explained.

First, to explain the lifting and lowering action of the workbench 10, a worker gets on the workbench 10 and puts on the helmet 2.
5 and put on the necessary materials. In this case, since the switch means 26 of the helmet 25 is in a free state without being pressed, the
The pressure sensitive body 28 expands due to its elasticity and the contact point 2
Turn off 9,30. Therefore, the solenoid valve 36
is de-energized and in the communicating position as shown in FIG. 4, thereby making it possible to supply oil to each hydraulic cylinder 17, 14, 12.

In this manner, when the operator operates the manual switching valve 42 of the control box 13 to the left in FIG. 4, the hydraulic pressure from the hydraulic pump 32 is supplied to one of the hydraulic cylinders 14, 12, causing it to extend. Therefore, the boom body 16, which had fallen down substantially horizontally, rotates and stands up due to the hydraulic cylinder 14, and at this time, the hydraulic cylinder 12 corrects the work platform so that it always maintains a horizontal state. After this, when the manual switching valve 42 is returned to its original position to stop the above operation, or when the manual switching valve 39 is also operated to the left in FIG. 4, pump hydraulic pressure is supplied to one side of the hydraulic cylinder 17 and it is extended. . Therefore, the hydraulic cylinder 17 causes the upper booms 8 and 9 in the boom body 16 to extend synchronously as described above, and this action causes the work platform 10 to extend.
and the workers aboard it ascend toward their high-altitude destinations. When the destination is reached, both manual switching valves 39 and 42 are returned to the neutral shutoff position, and the extension of each hydraulic cylinder 12, 14, 17 is stopped and the workbench 10 is held at that height position. , workers can perform a variety of high-altitude tasks. On the other hand, when the manual switching valves 39, 42 are operated in the opposite direction, the hydraulic cylinders 12, 14, 17 are contracted, and the work platform 10 descends while maintaining a horizontal state and returns to near the ground surface.

By the way, as long as the worker normally lifts and lowers the work platform 10, there will be no problem as described above, but if the worker neglects to stop the work platform 10 when raising it, the helmet 25 may fall into the tunnel as shown in FIG. 5B. When the helmet 2 collides with an obstacle S such as the ceiling of
The pressure sensitive body 28 in the switch means 26 of No. 5 is crushed to turn on the contacts 29 and 30. Therefore, the control circuit 43 immediately automatically switches the solenoid valve 36 to the cutoff position and stops supplying and discharging oil to the hydraulic cylinder side.
0 means an emergency stop to prevent the vehicle from rising any further.

It should be noted that the return after the emergency stop can be safely carried out in conjunction with the operation to temporarily return the two manual changeover valves 39 and 42 to the cutoff position.

As is clear from the above embodiments, according to the present invention, a pressure-sensitive switch means 26 is attached to the helmet 25 worn by the worker on the work platform 10 of the aerial work vehicle to emergency stop the elevation. This can protect the worker's safety in the event that the worker collides with the ceiling of a tunnel due to poor operation, or if an object falls from above. Furthermore, since the switch means 26 is disposed over substantially the entire area of the helmet 25, it operates effectively against obstacles directly above and on the sides, as well as against various postures of the worker, and there are few malfunctions. Furthermore, since the hydraulic circuit for lifting and lowering is cut off by the operation signal of the switch means 26, the responsiveness of the emergency stop operation is good and the control is easy.

In this embodiment, an elevating device using a multi-stage boom body has been described, but it goes without saying that the present invention can be similarly applied to other elevating devices such as a pantograph type.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing one embodiment of the present invention, FIG. 2 is a sectional view showing the extension and contraction mechanism of the boom body,
FIG. 3 is a perspective view showing the state in which the switch means is installed;
FIG. 4 is a hydraulic circuit diagram for lifting and lowering, and FIGS. 5A and 5B are sectional views showing the configuration and operating state of the switch means. 4... Vehicle body, 10... Workbench, 12, 14, 1
7... Hydraulic cylinder, 13... Control box, 1
6... Boom body, 25... Helmet, 26...
Switch means, 39, 42...Manual switching valve, 36
...Solenoid valve, 33, 35, 37, 38, 4
0,41...Oil road.

Claims (1)

[Claims] 1. In an aerial work vehicle in which a worker on a work platform ascends and descends by operating a switching valve in a hydraulic circuit having a plurality of hydraulic cylinders, a pressure-sensitive switch means is attached to the helmet worn by the worker, and the switch means is activated. 1. A lift stop device for an aerial work vehicle, characterized in that a solenoid valve in a hydraulic circuit is shut off in response to an operation signal to automatically bring a work platform to an emergency stop.