JPH0730626Y2 - Overload prevention device - Google Patents

Description

[Detailed Description of Device] a. The purpose of the invention (industrial field of application) The present invention relates to a work vehicle including a boom, which is capable of undulating, expanding and contracting, and swinging, such as a crane vehicle, aerial work vehicle, and digging column truck. The present invention relates to an overload prevention device that prevents a work vehicle from falling due to a moment generated according to an operation.

(Prior art) For work vehicles that perform work by hoisting and extending the boom, due to the weight of the boom and the suspension load at the boom tip,
A moment is generated around the base end (fulcrum) of the boom, causing the work vehicle to tip over. In order to prevent a fall due to such a moment, generally, for example, a rated moment is set by dividing the overturn moment (a moment of the size that causes the work vehicle to overturn) by a predetermined safety factor, and the moment reaches this rated moment. Then, an overload prevention device that restricts the operation of the boom toward the more dangerous side (in the direction of further increasing the moment) may be used. In many cases, such a device can always be freely operated on the safe side (direction of reducing the moment).

(Problems to be solved by the invention) However, in such a device, when the boom is subjected to the above operation restriction during work in a place where there are many obstacles such as a residential dense area, the safe operation is performed. There may be an obstacle such as a building or an electric wire in the direction, and in such a case, the boom cannot be operated in any direction, and there is a problem in that the boom gets stuck at a regulated position.

In view of the above problems, it is an object of the present invention to provide an overload prevention device capable of selecting the operation toward the dangerous side within a predetermined range when the boom is restricted in operation.

B. Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, in the present invention, a calculator for calculating a moment acting in the direction of overturning the work vehicle according to the operation of the boom and a moment A first operation restriction means for restricting the operation of the boom when the first moment limit set corresponding to the operation status of the boom is reached, and an operation for releasing the boom operation restriction by the first operation restriction means. The regulation release operation means and the boom operation regulation by the first operation regulation means when the regulation release operation means is operated, and the moment reaches the second moment limit, which is larger than the first moment limit. The overload prevention device is composed of the second operation restricting means for restricting the operation of the boom.

(Operation) In such a device, when the deregulation operation means is not normally operated and the moment reaches the first moment limit,
The operation of the boom toward the dangerous side is restricted (blocked). However,
If the boom's operation toward the dangerous side is restricted due to obstacles that prevent the boom from operating toward the safe side, you can operate the restriction release operation means to output a restriction release signal, and Can be temporarily released, and the boom can be operated toward the dangerous side until the moment reaches the second moment limit. Therefore, it is possible to easily get out of the stuck state as described above.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a digging column vehicle equipped with this device.

Outriggers 3 are provided at four positions on the front, rear, left, and right of the body 2 of the digger / columner 1. During work, the outriggers 3 are extended laterally and downward of the body 2 to stabilize the body 2 on the road surface. Support.

A swivel base 4 is attached to the rear portion of the vehicle body 2. The swivel base 4 can be swung freely by rotating a swivel motor 5 which is hydraulically operated. Further, the swivel base 4 includes a base end member 6a, an intermediate member 6b, and a front end member.
The base end of the boom 6 composed of 6c is pivotally attached.
The boom 6 can be freely lifted and retracted by the expansion and contraction operations of the undulation cylinder 7 and the expansion and contraction cylinder 8 that are hydraulically operated.

An auger device 11 is attached to a distal end portion of the base end side member 6a via a connecting member 10. The auger device 11 is for excavating a building hole or the like for the electric pole 12, and is composed of an auger motor 11a and an auger drill 11b connected to the auger motor 11a. In this figure, the auger device 11 is shown in a retracted state. However, when using the auger device 11, the auger device 11 is fixed to the distal end of the distal end side member 6c and moved along with the telescopic operation of the boom 6 to move it vertically. Suspend on the auger motor 11a
To rotate. In this way, the auger drill 11b rotates and drills a hole in the ground.

The hook 13a hung from the tip of the tip side member 6c by the wire 13 is for hanging a load such as a utility pole 12, and the wire 13 is a winch not shown (however, shown as WM in FIG. 1). The hoisting and lowering is performed by.

An operation seat 14 is attached to the swivel base 4, and an operator can operate the operation lever 30 to operate the boom 6, the auger device 11 and the winch described above.

Next, the configuration of the device ML will be described with reference to FIG.

This device ML includes a moment calculation unit 20, a main controller (first and second operation regulating means) MC, a regulation release switch (regulation releasing operation means) RS, and a valve controller VC.
It consists of and.

The moment calculation unit 20 includes a relief angle 21 and an extension amount sensor 22.
And a cylinder axial force sensor 23 and a calculator 24.

The hoisting angle sensor 21 and the extension amount sensor 22 detect the hoisting angle and the extension amount of the boom 6, respectively. Further, the cylinder axial force sensor 23 detects a force acting on the piston rod of the undulating cylinder 7 in the axial direction by the weight of the boom 6 and the weight of the suspended load such as the electric pole 12 suspended on the boom 6.

The computing unit 24 calculates the moment M acting in the direction of inclining the vehicle body 2 based on the signals from the sensors (21, 22, 23).

The restriction release switch RS is turned on / off by a worker, and outputs a restriction release signal when turned on.

The computing unit 24 and the restriction release switch RS are connected to the main controller MC via the moment signal line 25 and the release signal line 26, respectively, and the main controller MC
MC valve controller VC via regulation signal line 27
Connected to.

The valve controller VC is an operation signal from the operation lever 30 attached to the operation seat 14 and the main controller MC.
Based on the regulation signal from the valve unit VU, the solenoids of the undulating cylinder switching valve 7a, the telescopic cylinder switching valve 8a, the swing motor switching valve 5a, and the winch motor valve WM (not shown) are arranged in the valve unit VU. ) To the switch control signal. Each of these valves (5a, 7a, 8a, WM
In a), the supply / discharge control of the hydraulic oil from the hydraulic pressure source OP to each actuator (5, 7, 8, WM) is performed by energizing and de-energizing the solenoid.

Next, the operation of this device ML will be described using the control flow shown in FIG.

First, FIG. 2 shows a state in which the boom 6 is extended while the electric pole 12 that has been laid on the ground is being lifted by the raising operation of the boom 6 and the winding of the wire 13.

When the boom 6 operates in this way, step S in FIG.
In step 1 and step S2, the calculator 24 determines that each sensor (21, 2
The moment M is calculated based on the detection signal from (2, 23). Next, in step S3, the main controller
MC, the calculated moment M is the first moment limit M1
It is determined whether it is less than. Here, the first moment limit M1 is set to be smaller than the second moment limit (rated moment) M2 which is a limit value for stably supporting the vehicle body 2. These moment limits M
Fig. 4 shows the relationship between the working radius of the boom 6 and the hoisting load, which causes 1 and M2. Curve A in the figure corresponds to the first moment limit M1, and curve B is the second moment limit M2.
Corresponding to. When the moment M is less than the first moment limit M1 (M <M1), the process proceeds to step S4 and the operation lever 30
The valves (5a, 7a, 8a, WMa) are switched based on the operation of, and the boom 6 and the winch are freely operated. When the moment M reaches the first moment limit M (M =
M ₁ ) proceeds to step S5, and determines whether or not the restriction release switch RS is turned on, that is, whether or not the restriction release signal is input to the main controller MC. When the restriction release switch RS is off, the process proceeds to step S6 and the boom 6
To the dangerous side (in this case, the fall and extension movements)
Regulate (prevent) In this case, the boom 6 can be freely operated (standing and shortening) toward the safe side.

In this state where the operation of the boom 6 toward the dangerous side is restricted, as shown in FIG. 2, the tips of the boom 6 and the electric pole 12 approach the electric wire 15 above the work site. When it is in this state, the boom 6 is further operated to the safe side from this state,
That is, if the boom 6 or the utility pole 12 is actuated upright or shortened, the tip of the boom 6 or the utility pole 12 may come into contact with the wire 15. Therefore, as it is, the boom 6 cannot be operated to the dangerous side or the safe side. Therefore, in such a case, the operator turns on the restriction release switch RS. At this time,
The flow proceeds from step S5 to step S7.

In step S7, it is determined whether or not the moment M is greater than or equal to the first moment limit M1 and less than the second moment limit M2. Moment M is the second moment limit
When less than M2 (M <M _2), the process proceeds to step S8, thereby freely operating the boom 6 as in step S4. Therefore, the boom 6 can be operated further to the dangerous side from the state shown in FIG. Thus, for example, the boom 6 can be laid down to lower the tip of the electric pole 12 to a position lower than the electric wire 15 and then the boom 6 can be shortened.

Incidentally, moment M when it reaches the second moment limit M2 (M = M _2), the process proceeds from step S7 to step S9, to regulate the operation of the dangerous No more boom 6. Therefore, the fall of the vehicle body 2 is reliably prevented. In this case as well, the boom 6 can be operated to the safe side.

The overload prevention device described above can be used not only in a digging column truck, but also in a crane vehicle or an aerial work vehicle.

C. Effect of the Invention As described above, the use of the present overload prevention device normally restricts (blocks) the operation of the boom when the moment reaches the first moment limit, and after this restriction, the operator performs the selection operation. Based on the above, the regulation can be released and the operation of the boom can be allowed until the moment reaches the second moment limit. Therefore, even in a situation where the boom is restricted to the dangerous side due to the first moment limit and the safe side cannot be operated due to an obstacle or the like, the boom can be operated to the dangerous side to some extent by the above operation. It is possible to easily get out of the stuck state and improve work efficiency.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an overload prevention device according to the present invention, FIG. 2 is a perspective view showing a digging column vehicle equipped with the above device, and FIG. 3 is a control flow of the device. FIG. 4 is a graph showing the first and second allowable operating range limits. 5 ... Slewing motor, 6 ... Boom 7 ... Elevating cylinder, 8 ... Telescopic cylinder 12 ... Utility pole, 15 ... Electric wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Takeya Suzuki, Saitama Prefecture, Ageo City, Ryoke, Yamanashi 1152, 10 Aichi Vehicle Co., Ltd. Ageo Plant (72) Masaru Ishii, Saitama Prefecture, Ageo, Ryoke, Yamashita 1152 Address No. 10 Aichi Vehicle Co., Ltd. Ageo Factory (56) References Actually open 57-77294 (JP, U) Actually open 58-16800 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An overload prevention device which is attached to a work vehicle equipped with a boom capable of expanding, contracting, undulating, and turning, and which prevents the work vehicle from falling over by restricting the operation of the boom. A computing unit that calculates a moment acting in a direction of overturning the work vehicle in accordance with an operation, and an operation of the boom when the moment reaches a first moment limit set corresponding to an operating state of the boom. A first operation restricting means for restricting the operation of the boom, a restriction releasing operation means operated to release the operation restriction of the boom by the first operation restricting means, and a first operation restriction means for operating the restriction releasing operation means. When the operation restriction of the boom by the first operation restriction means is released and the moment reaches the second moment limit larger than the first moment limit, the boom is stopped. An overload preventing device comprising: a second operation restricting means for restricting operation of the boom.