JPH0114640Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a safety device for an aerial work vehicle.
As shown in Fig. 1, the aerial work vehicle has a swivel base 1 mounted on a traveling vehicle body A, and a base end of a boom 2 is pivotally connected to the swivel base 1 to form a fulcrum fulcrum 2'. , a workbench 3 is pivotally connected to the tip of this boom 2, and a luffing cylinder 4 is arranged between the swivel table 1 and the boom 2,
An upper leveling cylinder 5 is disposed between the tip of the boom 2 and the workbench 3, and a lower leveling cylinder 6 is disposed between the swivel base 1 and the boom 2. The upper leveling cylinder 5 and the lower leveling cylinder 6
have the same shape, and the extension operation side pressure oil chambers 5', 6'' and the contraction operation side pressure oil chambers 5'', 6' are communicated and connected via oil passages 7, 8. As a result, when the boom 2 is raised and lowered, the lower leveling cylinder 6 is extended and the upper leveling cylinder 5 is contracted, and when the boom 2 is lowered, the lower leveling cylinder 6 is contracted and the upper leveling cylinder 5 is extended, and the work platform 3 is Regardless of whether the boom 2 moves up or down, it can always maintain a constant angle with respect to the ground. In addition, 9 and 10 are
These are pilot check valves installed in oil passages 7 and 8, respectively.

By the way, this type of aerial work vehicle is Boom 2,
The moment in the boom lodging direction that is generated around the lifting fulcrum of the boom 2 due to the weight of the work platform 3, the worker on the work platform, and the equipment is the moment that occurs in each boom state (each state that changes as the boom moves up and down, the boom 2 expands and contracts). In the case of the type, if the predetermined limit value is exceeded for each condition that changes due to the boom's hoisting motion and extension/contraction motion, it will cause an accident of overturning or destruction. A safety device is installed that will alarm or restrict boom movement when the limit value is reached.

A conventional safety device will be explained based on FIG.
In Fig. 3, the safety devices include a load detector a that detects the force F acting in the axial direction of the hoisting cylinder 4; an angle detector b that detects the hoisting angle of the boom 2; The limit value of the load on the cylinder 4 is memorized, the angle signal from the angle detector b is used as a readout signal, the limit value at the boom heave angle at that time is read out, and the read limit value and the load signal from the load detector a are read out. It is comprised of an arithmetic unit c which compares the value and outputs an alarm or a signal to restrict the movement of the boom 2 when the latter value reaches the former value. In addition, when the boom 2 is a telescopic type, a boom length detector d is added, and the calculation device c is made to store each luffing angle of the boom 2 and the limit value for each boom length, and the angle Each detection signal from the detector b and the boom length detector d is used as a readout signal to read out the limit value corresponding to the boom heave angle and boom length at that time, and thereafter processed in the arithmetic unit c in the same manner as above. There is.

The conventional safety device configured in this way takes the corresponding value of the moment in the lodging direction generated around the boom's hoisting fulcrum as the force F acting on the hoisting cylinder that supports the moment and orients the boom 2, and calculates the force F. The safety of work using aerial work vehicles is ensured by checking to see if the limit has been reached.

However, in the case of an aerial work vehicle, the weight of the boom 2, the work platform 3, and the workers and equipment on the work platform 3 maintains the moment in the boom lodging direction that is generated around the boom 2 lifting fulcrum. It is not only the hoisting cylinder 4 that maintains the position, but also the lower leveling cylinder 6 interposed between the swivel base 1 and the boom 2, which also shares the function of holding the moment in the lodging direction and positioning the boom 2. be. That is, the workbench 3 is connected to the upper leveling cylinder 5, which functions to keep the attitude of the workbench 3 constant regardless of the up-and-down movement of the boom 2.
The same force acting from the lower leveling cylinder 6 acts on the boom 2, and this force carries a part of the moment in the direction of lodging the boom. For this reason, the force F acting on the undulating cylinder 4
Conventional safety devices for aerial work vehicles, which measure only the force F and visually check whether this force F reaches a limit value, have a problem in that they cannot accurately monitor the safety of the work of the aerial work vehicle.

An object of the present invention is to provide a new safety device that solves the problems of the conventional safety devices described above and can accurately monitor the safety of work using a vehicle for working at heights.

(Means for Solving the Problems) In order to achieve the above object, the safety device for a high-altitude work vehicle of the present invention is configured as follows.

A base end of a boom 2 is pivotally connected to the swivel base 1 to form a hoisting fulcrum, a work platform 3 is pivotally connected to the tip of the boom 2, and a hoisting cylinder 4 is connected between the boom 2 and the swivel base 1. , an upper leveling cylinder 5 is disposed between the workbench 3 and the tip of the boom 2, a lower leveling cylinder 6 is disposed between the swivel base 1 and the boom 2, and the upper leveling cylinder 5 and the lower leveling cylinder 6 are extended. This is a safety device used in an aerial work vehicle in which an operating side pressure oil chamber and a contracting operation side pressure oil chamber are connected via oil passages 7 and 8, respectively, and the force acting in the axial direction of the hoisting cylinder 4. a first load detector that detects the force acting in the axial direction of the lower leveling cylinder 6, an angle detector that detects the luffing angle of the boom 2, and a position around the boom hoisting fulcrum. A limit value corresponding to the permissible limit of the boom lodging direction moment acting on the boom is memorized for each boom lofting angle, and the limit value at the boom lofting angle at that time is read out using the angle signal from the angle detector b as a readout signal, This read limit value is
Compare the detected values of both load detectors with the sum of the detected values, and if the latter value reaches the former value, an alarm or boom 2
A safety device for an aerial work vehicle, characterized in that the device is configured to emit a signal to restrict movement of the vehicle.

(Function) According to the above configuration, the value corresponding to the moment in the lodging direction acting on the boom 2 is maintained by the hoisting cylinder 4 that holds the moment and orients the boom 2.
Since this is the added value of the loads of both the lower leveling cylinder 6 and the lower leveling cylinder 6 and is compared with the limit value, the safety of the aerial work vehicle can be monitored extremely accurately.

(Example) A specific example of the present invention will be described in detail below based on FIG. 2.

FIG. 2 shows the safety device of the present invention, in which a first load detector a detects a force F acting in the axial direction of the luffing cylinder 4; a first load detector a detects a force f acting in the axial direction of the lower leveling cylinder 6; 2 load detector e; angle detector b that detects the heave angle θ of the boom 2; boom length detector d that detects the boom length l; and the first load detector a and the second load. It is comprised of a computing device c that receives signals from a detector e, an angle detector b, and a boom length detector d, performs arithmetic processing on the basis of these signals, and outputs an alarm signal or a signal that limits the movement of the boom.

In the figure, 15 to 18 are each detector a,
This is an amplifier that amplifies the outputs of e, b, and d and inputs them to the arithmetic unit c.

The arithmetic unit c will be specifically explained. 19 is
It is an analog switch, and receives a control signal from an address decoder 22, which will be described later, to control each of the amplifiers 15.
18 are periodically selected and sent to the A/D converter 20. Reference numeral 21 denotes an input gate, which passes a signal from the A/D converter 20 to the CPU 23 in response to a control signal from the address decoder 22. 24 is the program ROM
It has a built-in arithmetic program, and the CPU 23 controls arithmetic processing and the address decoder 22 according to this program. Reference numeral 25 is a data ROM, in which limit values for each elevation angle and each length of the boom 2 are stored. This limit value corresponds to the allowable limit value of the moment in the boom lodging direction that is generated around the boom hoisting fulcrum due to the dead weight of the boom 2, the dead weight of the work platform 3, and the dead weight of workers and equipment mounted on the work platform 3. It is. In addition to the above-mentioned limit values, the data ROM 25 also contains the distance of the boom's hoisting fulcrum 2' with respect to the axis of the hoisting cylinder 4 for each hoisting angle of the boom 2 (hereinafter referred to as the moment arm length of the hoisting cylinder 4), and the following leveling information. cylinder 6
The distance (hereinafter referred to as the moment arm length of the lower leveling cylinder 6) of the boom lifting fulcrum 2' with respect to the axis of is stored. 26 is RAM;
The signals from each of the detectors a, e, b, and d are temporarily stored while being continuously updated. 27 is an alarm which is an external device, and an alarm driver 28
controlled by. 29 is alarm driver 2
When a signal to drive the alarm driver 2 is issued from the CPU 23, this signal is held until a new signal is issued from the CPU 23 again.
This is an output latch that continues to drive 8. 30 is a numerical display which is an external device, and indicates the value obtained by dividing the response value of the actual moment by the response value of the limit moment as a percentage. 31 is a latch decoder driver, which transmits the signal from the CPU 23 to the numerical display 30.
The numerical display 30 continues to display the same numerical value until a new signal is sent from the CPU 23.

The arithmetic processing by the arithmetic device c is as follows.

Let us now assume that the boom angle in any working state is θ, and the boom length at this time is l. At this time, the first load detector a and the second load detector e detect the force acting in the axial direction of the hoisting cylinder 4 and the force acting in the axial direction of the lower leveling cylinder 6, respectively.
Also, the angle detector b and the boom length detector d are connected to the above-mentioned θ,
1 is converted into a signal and sent to the analog switch 19 of the arithmetic unit c. The address decoder 22 outputs a signal to the analog switch 19 to sequentially send the signals to the A/D converter 20 side. Then, among the signals taken into the CPU 23 via the A/D converter 20, limit values corresponding to the boom heave angle θ and the boom length l are determined from the data ROM 25 based on the θ signal and l signal. Read out. Furthermore, based on the boom hoisting angle θ signal, data on the moment arm length of the hoisting cylinder 4 and the lower leveling cylinder 6 are output from the data ROM 25.
The moment arm length data of is read out. The read moment arm length data of the undulation cylinder 4 is multiplied by the detection signal from the first load detector. This multiplication result is a value corresponding to the moment shared by the undulation cylinder 4. Further, the read moment arm length data of the lower leveling cylinder 6 is multiplied by the detection signal from the second load detector. This multiplication result is a value corresponding to the moment shared by the lower leveling cylinder 6. Next, the CPU 23 adds up the multiplication results to determine the response value of the moment carried by both the undulating cylinder 4 and the lower leveling cylinder 6. The value obtained in this way is a value that responds to the actual moment generated around the boom hoisting fulcrum due to the dead weight of the boom 2, the dead weight of the work platform 3, and the dead weight of the worker and equipment on the work platform 3. be. A signal obtained by dividing the actual moment response value by the limit moment response value is sent from the CPU 23 to the latch decoder driver 31, and the numerical display 30 displays this value as a percentage. When this value reaches 100%, the CPU 23 issues a signal to activate the alarm 27, and the alarm 27 issues an alarm.

In this embodiment, the calculation device c stores the limit value corresponding to the permissible limit of the boom lodging direction moment used around the boom hoisting fulcrum for each boom length and for each boom hoisting angle, and the angle detector b and The angle signal and length signal from the boom length detector d are used as readout signals to read out the limit values for the boom heave angle and boom length at that time, and the read limit values are used as the sum of the first and second load detectors. The structure is such that a signal is emitted when the latter value reaches the former value. In addition,
In the above embodiment, an example has been described in which the alarm 27 is activated, but a solenoid valve may be activated at the same time to stop the actuator of the aerial work vehicle.

In addition, in the above embodiment, an example was shown in which the boom 2 is extendable and retractable, but when it is applied to a boom 2 that is not extendable and retractable, the boom length detector d is eliminated and the arithmetic unit c is The stored limit value may be set to a specific boom length stored for each boom angle.

Furthermore, aerial work vehicles generally have outrigger devices on the front and rear of the vehicle body, and the work performance differs depending on the amount of overhang of this outrigger device and the swivel angle of the swivel platform. , the data ROM stores the response value of the critical moment in response to the turning angle and the amount of extension of the outrigger device, and the stored value is retrieved based on the input signals from the outrigger extension amount detector and the turning angle detector. This is especially effective in making the most of the capabilities of the aerial work vehicle.

(Effects) The safety device for the aerial work vehicle of the present invention, which is constructed and operates as described above, calculates the value corresponding to the boom lodging direction moment generated around the boom's hoisting fulcrum, not only the force acting on the hoisting cylinder but also the Since it is also detected from the force acting on the leveling cylinder, its accuracy is improved compared to conventional ones, which makes it possible to accurately check the safety of work with aerial work vehicles, and to ensure safe operation. It is a great contribution to the work.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an aerial work vehicle to which the safety device of the present invention is applied, FIG. 2 is an explanatory diagram of the safety device according to the present invention, and FIG. 3 is an explanatory diagram of a conventional safety device.

Claims (1)

[Scope of utility model registration request] A base end of a boom 2 is pivotally connected to the swivel base 1 to form a levitation fulcrum, a work platform 3 is pivotally connected to the tip of the boom 2, and a levitation cylinder 4 is connected between the boom 2 and the swivel base 4. An upper leveling cylinder 5 is disposed between the workbench 3 and the tip of the boom 2, and a lower leveling cylinder 6 is disposed between the swivel base 1 and the boom 2, and the upper leveling cylinder 5 and the lower leveling cylinder 6 are extended. This is a safety device used in an aerial work vehicle in which an operating side pressure oil chamber and a contracting operation side pressure oil chamber are connected via oil passages 7 and 8, respectively, and the force acting in the axial direction of the hoisting cylinder 4. a first load detector a that detects the force acting in the axial direction of the lower leveling cylinder 6, a second load detector e that detects the force acting in the axial direction of the lower leveling cylinder 6, an angle detector b that detects the up-and-down angle of the boom 2, and A limit value corresponding to the permissible limit of the boom lodging direction moment acting around the boom hoisting fulcrum is stored for each boom hoisting angle, and the angle signal from the angle detector b is used as a readout signal to determine the limit at the boom hoisting angle at that time. The readout limit value is compared with the sum of the detection values of both load detectors a and e, and when the latter value reaches the former value, an alarm or a signal to limit the movement of the boom 2 is issued. A safety device for an aerial work vehicle characterized by the following configurations.