JPS63159723A - Workbench load measuring instrument for high place working car - Google Patents

Abstract

PURPOSE:To accurately measure a load placed on a workbench under various in-use conditions by detecting a value, etc., responding to moment applied from a hydraulic actuator boom for boom hoisting driving. CONSTITUTION:A boom 12 is hoisted by hydraulic actuators 14L and 14R arranged on both sides on a base 10 provided at the upper part of a car body. Then boom moment response values responding to moment applied from the boom 12 to the actuators 14L and 14R are detected by moment detectors 16L and 16R respectively. Further, the hoisting angle of the boom 12 is detected by a boom hoisting angle detector and the length of the boom 12 is detected by a boom length detector respectively. Further, a weight body 26 is mounted on the workbench 22 and moment response values responding to moment applied from this workbench 22 to the hydraulic actuators 24L and 24R are detected by moment detectors 28L and 28R. Then, the load to be measured is calculated from the output values of the detectors.

Description

DETAILED DESCRIPTION OF THE INVENTION (J12 Field of Industrial Application) The present invention relates to a work platform load measuring device for an aerial work vehicle that determines the load of the work platform of an aerial vehicle.

(Prior art) Regarding aerial work vehicles, the technology described in Japanese Patent Application Laid-Open No. 60-232400 is known, and in this type of aerial work vehicles, the work platform is driven up and down in a horizontal position. .

The workbench is provided at the tip of a telescoping boom that is driven to raise and lower with respect to the base of the vehicle, and hydraulic actuators are used to drive the boom to raise and lower and to maintain the horizontal posture of the workbench.

(Problem to be solved by the invention) Here, in order to prevent the load applied to the hydraulic actuator, boom, etc. from becoming overloaded and to ensure work safety, the allowable load applied to the work platform is designed according to the design. It has been decided.

The permissible load is generally set at a constant value in consideration of various conditions such as the boom angle.

On the other hand, in reality, the allowable load differs depending on the boom's elevation angle, and if the work platform is wide in the length direction of the boom, when a worker or object moves on the work platform, it will depend on the movement position. The moment of the load acting on the workbench changes, and therefore the allowable load also changes.

Therefore, depending on the boom angle, etc., it may not be necessary to strictly adhere to the determined allowable load value.

However, in the past, the allowable load was set to a constant value, and the load applied to the workbench was limited based on the allowable load, so this limit was not always properly applied in actual work sites.

In order to appropriately limit this, it is desirable to successively and accurately measure the load applied to the workbench in accordance with the usage situation.

The present invention has been made in view of the above-mentioned conventional circumstances, and its purpose is to accurately control the load applied to the workbench under various usage conditions, such as when workers and objects move on a wide workbench (platform). An object of the present invention is to provide a work platform load measuring device for an aerial work vehicle that can determine a load of 81 g.

(Means for Solving Problem No.) In order to achieve the above object, the work platform load measuring device for an aerial work vehicle according to the present invention has a base end that is undulating with respect to the base, as shown in FIG. boom moment detection means a for detecting a value responsive to a moment applied from the boom to a boom hoisting drive hydraulic actuator for hoisting and hoisting of the freely pivoted boom; and boom hoisting angle detection means for detecting the hoisting angle of the boom. and a work platform moment detection unit that detects a value in response to a moment applied from the work platform to a hydraulic actuator for horizontally holding the work platform, which holds the work platform attached to the tip of the boom horizontally regardless of the up-and-down movement of the boom. means C; boom length detection means d for detecting the length of the boom; and a boom length detection means d for detecting the length of the boom; The present invention is characterized by having a workbench load calculation means C for calculating the load applied to the workbench.

(Function) In the work platform load measuring device for an aerial work vehicle according to the present invention, the value responsive to the moment applied from the boom to the boom hoisting drive hydraulic actuator, the boom hoisting angle, the boom length, and the work platform horizontal A value responsive to the moment applied from the work platform to the holding hydraulic actuator is detected,
The load applied to the workbench is calculated based on these detected values.

(Embodiments) Hereinafter, a preferred embodiment of the work platform load measuring device for an aerial work vehicle according to the present invention will be described based on the drawings.

Figure 2 shows the right side of a so-called boom-type aerial work vehicle.
Figure 3 shows its front view.

A boom 12 is mounted on a base 10 provided at the top of the vehicle body.
are hydraulic actuators 14L and 1 arranged on both sides thereof.
It is driven up and down by 4R.

Boom moment response values in response to the moment applied from the boom 12 to each hydraulic actuator 14L, 14R are detected by moment detectors 16L, 16R, respectively.
6R consists of strain gauges attached to the piston rods of the hydraulic actuators 14L and 14R.

Furthermore, the boom 12's hoisting angle is determined by the boom hoisting angle detector 1.
8, and the length of the boom 12, which extends and contracts, is detected by the boom length detector 20.

At the tip of this boom 12, a workbench 22 is rotatably supported on the front side of the vehicle, and the workbench 22 is wide in the longitudinal direction of the vehicle, as can be understood from FIGS. 2 and 3. It has become.

In addition, a hydraulic actuator 2 is mounted on the extending side of the boom 12.
4L and 24R are provided respectively, and the second
In the figure, the substantially central lower portion of the workbench 22 is driven to suppress the boom 12 in a direction in which it expands.

These hydraulic actuators 24L, 24R are controlled in conjunction with the hydraulic actuators 14L, 14R.

As a result, the workbench 22 is always held in a horizontal position.

A heavy object 26 (for example, a worker or various work equipment) is placed on one workbench 22, and this workbench 22
Moment response values responsive to the moments applied from the hydraulic actuators 24[4, 24R to the hydraulic actuators 24[4, 24R] are detected by moment detectors 28L, 28R, respectively.

Incidentally, the moment detectors 28L and 28R are constituted by strain gauges attached to the piston ronds of the hydraulic actuators 24L and 24R, respectively.

Furthermore, it is also preferable to control each of the hydraulic actuators 24L and 24R by detecting the horizontal level of the workbench 22.

Figure 4 shows moment detectors 16L, 16R, 28L,
28R.

Boom hoisting angle detector 18. An alarm control circuit 30 is shown to which the detection signal of the boom length detector 20 is applied.

This alarm control circuit 30 is mainly configured with a CPU 32, and a program ROM 3 for the CPU 32.
4. A data ROM 36 and a work RAM 38 are provided.

And amplifiers 40, 42, 44 of this alarm control circuit 30
.

46 is the detection signal of the moment detectors 16L and 16R,
Detection signals from the boom hoisting angle detector 18, boom length detector 7, and moment detectors 28L and 28R are supplied, respectively, and these amplified signals are sent to the analog switch 48 and the A/D converter 50. ．． It is taken in via the input gate 52.

In addition, the aerial work vehicle in this embodiment is provided with an outrigger device (not shown) that supports the vehicle body, and heavy objects that can be placed on the workbench 22 according to the amount of overhang of the outrigger device. Since the allowable loads of the outrigger devices 26 are different from each other, a state detector 54 is provided to detect the amount of overhang of the outrigger device.

A switching signal from the state detector 54 is applied to an input gate 58 via a switch input interface 56, and switching signals from three display changeover switches 60 are also applied to the input gate 58.

Note that the display changeover switch 60 is provided for the operator to select display values (for example, the angle of elevation, length, etc. of the boom 12) displayed on a single display section.

Further, the alarm control circuit 30 is provided with a numerical display @ 62 and a unit display 64 for displaying the numerical unit. The contents of the output latch 70 are displayed by the ED driver 72.

and output latch 74 causes driver 76.78.80
is controlled, the warning indicator light 82 lights up, and the warning buzzer 8
4 and the solenoid valve 86 is driven.

Note that these controls are performed when the load applied to the workbench 22 becomes excessive, and the alarm indicator light 82 and alarm buzzer 8
4 gives a warning to the operator.

Further, the operation of each hydraulic actuator 14L, 14R, 24L, and 24R is controlled to stop by driving the solenoid valve 86, so that the workbench 22 is held in the posture position at that time.

The alarm buzzer 84 and solenoid valve 86 are externally attached to the alarm control circuit 30, and the alarm control circuit 30 is provided with an address decoder 49 for chip selection and the like.

This embodiment has the above configuration, and its operation will be explained below.

As shown in Figure 2, everyone FW (load applied to the workbench 22),
RP (distance from the fulcrum of the boom 12 to the center of gravity of the work platform 22), RW (distance from the fulcrum of the boom 12 to the center of gravity of the heavy object 26), FP (self-weight of the work platform 22), R (boom 1
2), R8 (distance from the fulcrum of the boom 12 to the center of gravity of the boom 12), BL (length of the boom 12), FB (boom 12's own weight), C11 (boom 1z)
) is determined, the moment EIIIOM is applied from the boom 12 to the hydraulic actuators 14L and 14R.

It is expressed as EMOM=Rw-FW+RP-FP+RB-FB.

In addition, the workbench 22 is attached to the hydraulic actuators 24L and 24R.
The moment LON applied from is: LMOM= (R-Rw) ・FW+ (R-RP)
- Represented by FP.

When those moments EMOM and LMOM are added.

EMOM+LMOM=Rw-FW+RP-FP1RB
-FB+ (R-R1/) -FW+ (R-RP)
-FP=l(-Fv+R-FP+RB -FB・(1)
Therefore, EMOM+LMOM=R-(FW+FP) +RB-
FB・(2) is obtained.

As understood from this equation (2), it is possible to always handle the one-heavy object 26 on the workbench 22 as being located at the right end indicated by the broken line in FIG.

Further transforming equation (1), R-F%l=HMOM+LMOM-R-FP-RB −
Since it becomes FB, the value FW is shown by the following formula (3).

FW= (EMOM+LMOM-(R-FP+RB-
FB)) /R-(3) And in the above formula (3).

IEMOI, the moment response values detected from the moment detectors 16L and 16R, and the moment arm (this moment arm is a function that uses the heave angle of the boom 12 as a variable, and the calculation formula of the function is stored in advance in the program ROM.
34) can be calculated as an integrated value.

On the other hand, LMOM can be calculated as an integrated value of the moment response values detected from the moment detectors 26L and 26R, respectively, and the moment arm.

Also, between the value (R-FP+RB-FB) and the value R, the value R
is calculated based on the surface output values from the boom lifting angle detector 18 and the boom length detector 20, and the value FP and the value FB are constants.

Furthermore, the value RB is a function that uses the boom 12's heave angle and length as variables, and the calculation formula for the function is stored in the program ROM 34 in advance. It can be calculated based on the surface output value from the device 20.

From the above explanation, the load Fit to be measured is a function whose variables are the values detected by the moment detectors 16L, 16R, 28L, 28R, the boom heave angle detector 18, and the boom length detector 20, and therefore the load It is understood that FW can be calculated based on the output value of each detector.

Fig. 5 schematically shows the aerial work vehicle shown in Fig. 2, and as shown in the figure, the values Ml (EMOM) and M2 (LMOM) are
, x (RP), y (R-RP), FW, and θ (θB) are determined.

The boom moment M1 detected by the moment detectors 16L and 16R is expressed as: Old = (boom dead weight moment) + (work platform dead weight moment) + FW・X, and the work platform moment M2 is.

It is expressed as M2=(workbench weight moment)+FW-y.

Therefore, the sum of those moments Ml and M2 is Ml + M2
=F11- (x+y) + (sum of self-weight moments) =FW- (boom length)・C08O+ (sum of self-weight moments), so moments Ml, M2, boom length (
BL), it is possible to always accurately determine the load FW of the heavy object 26 from the boom elevation angle θ regardless of its position.

In addition, when the work platform 22 is extended to the right by the tip of the boom 12 as shown in Fig. 6, M1 = Dead weight moment (boom, work platform) + FW・XM
2 = Dead weight moment (workbench) + Fw-y old - M2 = F
W・(x−y)+(difference in self-weight moment)=Fw・(boom length)・cosθ+(difference in self-weight moment) is established, and the load FllI is obtained in the same way as in the case of FIG.

In the alarm control circuit 30 of FIG. 4, the moment detector 16L
, 16R, 28L, 28R, boom elevation angle detector 18
Characteristics in which the detected value of the boom length detector 20 is used as a variable and the load FW as a function are prepared in advance on the table of the data ROM 36, and as shown in FIG. 7, the CPU 32 uses these detected values to calculate the load FW. A search operation is performed from the table (step 1oo-103).

That is, when the detected values from each of the above-mentioned detectors are input in step 1oo, in the first step 102, the detected values by the moment detector 16L and the moment detector 16 are inputted.
The average value with the detected value by R, and the moment detector 28
The average value of the value detected by L and the value detected by the moment detector 28R is calculated.

Then, these calculated values are used in the search calculation of the load Fll in the next step 103.

Therefore, the load FW can be accurately determined no matter where the heavy object 26 is located on the workbench 22 in the vehicle width direction.

When the load FW is determined in this way, the load Fv
It is determined whether or not the amount is excessive by comparing it with a pre-stored limit value (a function whose variables are the heave angle and length of the boom 12) (step 104), and if it is excessive, a warning is displayed. The light 82 is turned on and the alarm buzzer 8 is activated.
4 is sounded, and the solenoid valve 86 is further driven (step 105).

Then, in the next step 106, the load FW is displayed on the numerical display 62 and unit display 64.

In this embodiment, the safety device such as the warning indicator light 82 is activated by comparing the load FW with the limit value in step 104, but step 10
4, the above moment EMOM and the above moment LMOM
and a limit value (a limit value of moment response values stored in advance as a function of the undulation angle and length of the boom 12), the safety device is configured to operate. Also good.

As explained above, in this embodiment, even when the heavy object 26 is moved to any position in the longitudinal direction or width direction of the vehicle on the first workbench 22, the load Fit of the heavy object 26 is accurate regardless of the position. is measured.

Therefore, regardless of the moving position of the heavy object 26, it is possible to use the alarm indicator light 82, alarm buzzer 84, and solenoid valve 86 to accurately limit the load on the workbench 22, thereby achieving extremely high safety. It becomes possible to secure it.

(Effects) As can be understood from the above explanation, in the work platform load measuring device for an aerial work vehicle according to the present invention, even if a worker or the like moves in the longitudinal direction of the boom on a wide work platform.

The load applied to the workbench is accurately measured regardless of its moving position.

As a result, it is possible to appropriately limit the load on the workbench, thereby ensuring extremely high safety.

[Brief explanation of the drawing]

Figure 1 is a complaint response diagram, Figure 2 is a right side view of the aerial work vehicle, Figure 3 is a front view of Figure 2, and Figure 4 is an explanation of the configuration of the alarm control circuit that measures the load applied to the workbench. Figures 5 and 6 are diagrams explaining the calculation effect of the load applied to the workbench.
The figure is a flowchart explaining the operation of the embodiment. 12...Boom 18...Boom hoisting angle detector 14L, 14R, 24L, 24R...Hydraulic actuator 16L, 16R, 28L, 28R...Moment detector 20...Boom length detector

Claims (2)

[Claims] (1) A boom moment detection means for detecting a value responsive to a moment applied from the boom to a boom hoisting hydraulic actuator for hoisting a boom whose base end is pivotably supported to a base so that the boom can be hoisted, and the boom a boom elevation angle detection means for detecting the elevation angle of the boom; and a moment applied from the work platform to a hydraulic actuator for horizontally holding the work platform, which holds the work platform installed at the tip of the boom horizontally regardless of whether the boom moves up or down. a work platform moment detection means for detecting a value responsive to the boom length; a boom length detection means for detecting the length of the boom; a value responsive to the detected boom moment, a boom luffing angle, and a value responsive to the work platform moment. and a work platform load calculation means for calculating the load applied to the work platform based on the length of the boom. (2) The boom moment detection means is provided for each of the boom hoisting drive hydraulic actuators disposed on both sides of the boom, and the work platform moment detection means is provided for each of the boom hoisting drive hydraulic actuators disposed on both sides of the boom for horizontally maintaining the work platform. The work platform load measuring device for an aerial work vehicle according to claim 1, wherein the device is provided for each hydraulic actuator.