JPH0678930B2 - Platform load measuring device for aerial work platforms - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a workbench load measuring device for an aerial work vehicle that measures the load on the workbench of the aerial work vehicle.

(Prior Art) With regard to an aerial work vehicle, a technique described in Japanese Patent Laid-Open No. 60-232400 is known, and in this type of aerial work vehicle, the workbench is vertically moved up and down. .

The workbench is provided at the tip of a telescopic boom that is driven up and down with respect to the base of the vehicle, and hydraulic actuators are used to drive the boom up and down and hold the workbench in a horizontal position.

(Problems to be solved by the invention) Here, in order to prevent the load applied to the hydraulic actuator, the boom, and the like from being overloaded and ensure work safety, the allowable load applied to the workbench is designed. Has been decided.

The allowable load is generally set to a constant value in consideration of various conditions such as the hoisting angle of the boom.

On the other hand, in reality, the allowable load differs depending on the hoisting angle of the boom, and if the workbench is wide in the length direction of the boom, when a worker or object moves on the workbench, the allowable load will be changed according to the movement position. As a result, the moment of the load acting on the workbench changes, and therefore the allowable load also changes.

Therefore, depending on the hoisting angle of the boom and the like, it may not always 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. Therefore, the limit is not necessarily properly set in the actual site.

Then, in order to properly carry out the restriction, it is desirable that the load applied to the workbench is successively and accurately measured in accordance with the usage situation.

The present invention has been made in view of the above conventional circumstances, and an object thereof is to accurately determine the load applied to a workbench even under various usage conditions such as movement of a worker or an object on a wide workbench (platform). An object is to provide a work platform load measuring device for an aerial work vehicle that can measure at high speed.

(Means for Solving Problems) In order to achieve the above object, a work platform load measuring apparatus for an aerial work vehicle according to the present invention has a base end portion undulating with respect to a base as shown in FIG. A boom moment detecting means a for detecting a value in response to a moment applied from the boom to a boom hoisting hydraulic actuator for hoisting a freely pivoted boom, and a boom hoisting angle detecting means b for detecting a hoisting angle of the boom. And a workbench moment detection for detecting a value in response to a moment applied from the workbench to a workbench horizontal holding hydraulic actuator that holds the workbench attached to the tip of the boom horizontally regardless of the hoisting motion of the boom. Means c, a boom length detecting means d for detecting the length of the boom, a value responsive to the detected boom moment, a hoisting angle of the boom, and a platform table. The workbench load calculating means e for calculating the load applied to the workbench based on the value in response to the boom and the length of the boom. The workbench load detecting means e changes the workbench moment from the value corresponding to the boom moment. Subtract the corresponding value, then subtract the value corresponding to the moment acting around the boom hoisting fulcrum based on the boom's own weight, divide the result by the boom's working radius, and then subtract the worktable's own weight from the result of the work. It is characterized in that it is configured to calculate the load applied to the table.

(Operation) In the work platform load measuring apparatus for an aerial work vehicle according to the present invention, the work platform horizontal holding is performed together with the value responsive to the moment applied from the boom to the boom hoisting drive hydraulic actuator, the boom hoisting angle, the boom length. The value that responds to the moment applied from the workbench to the hydraulic actuator for
The load applied to the workbench is calculated based on the detected values.

(Embodiment) A preferred embodiment of a work platform load measuring apparatus for an aerial work vehicle according to the present invention will be described below with reference to the drawings.

Fig. 2 shows the right side of a so-called boom type aerial work vehicle.
The front view is shown in FIG. A boom 12 is erected on a base 10 provided at the upper part of the body of this aerial work vehicle, and the boom 12 is mounted on both sides of the boom 12 between the boom 12 and the base 10. The hydraulic actuators 14L and 14R are driven up and down.

Then, the boom moment response values in response to the moments applied to the hydraulic actuators 14L and 14R from the boom 12 are respectively detected by the moment detectors 16L and 16R,
The moment detectors 16L and 16R are hydraulic actuators 1
It consists of strain gauges attached to 4L and 14R piston rods.

Further, the hoisting angle of the boom 12 is detected by the boom hoisting angle detector 18, and the length of the boom 12 that expands and contracts is detected by the boom length detector 20.

A vehicle front side of a workbench 22 is rotatably supported at the tip of the boom 12, and the workbench 22 is wide in the front-rear direction of the vehicle as can be understood from FIGS. 2 and 3. ing.

In addition, hydraulic actuator 24L,
24R are provided respectively, and by these, the substantially central lower portion of the workbench 22 is pressed and driven in the direction of expanding with respect to the boom 12 in FIG.

These hydraulic actuators 24L, 24R are controlled in conjunction with the hydraulic actuators 14L, 14R, and as a result, the workbench 22 is always held in a horizontal posture.

A heavy object 26 (for example, a worker or various types of work equipment) is placed on the workbench 22, and the moment response value in response to the moment applied from the workbench 22 to the hydraulic actuators 24L, 24R is the moment. Each is detected by the detectors 28L and 28R.

The moment detectors 28L and 28R are hydraulic actuator 2
It consists of strain gauges attached to 4L and 24R piston rods.

In addition, the control of each hydraulic actuator 24L, 24R
It is also preferable to carry out the horizontal detection.

FIG. 4 shows an alarm control circuit 30 to which the detection signals of the moment detectors 16L, 16R, 28L, 28R, the boom hoisting angle detector 18, and the boom length detector 20 are given.

The alarm control circuit 30 is mainly composed of a CPU 32, and a program ROM 34 and a data ROM 3 are provided for the CPU 32.
6, work RAM 38 is provided.

The alarm control circuit 30 includes amplifiers 40, 42, 44 and 46 having detection signals from the moment detectors 16L and 16R, a boom hoisting angle detector 18, a boom length detector 20, and a moment detector 28L. , 28R detection signals are respectively supplied, and their amplified signals are taken in through the analog switch 48, the A / D converter 50, and the input gate 52.

Further, an aerial work vehicle in the present embodiment is provided with an outrigger device (not shown) for carrying the vehicle body, and a heavy load that can be placed on the workbench 22 according to the overhang amount of the outrigger device. Since the allowable loads of 26 are different from each other, the state detector 54 for detecting the overhang amount of the outrigger device is provided.

The switching signal of the state detector 54 is given to the input gate 58 through the switch input interface 56, and the switching signal is also given to the input gate 58 from the three display changeover switches 60.

The display changeover switch 60 is provided for the operator to select the display value (for example, the hoisting angle and length of the boom 12) displayed on the single display unit.

Further, the alarm control circuit 30 is provided with a numerical display 62 and a unit display 64 for displaying the numerical unit, and the numerical display 62 displays the numerical value of the output latch 66 by the LED driver 68.
The contents of the output latch 70 are displayed on the unit display 64 by the LED driver 72.
Displayed by.

The drivers 76, 78, 80 are controlled by the output latch 74, and the alarm indicator lamp 82 is turned on, the alarm buzzer 84 is activated, and the solenoid valve 86 is driven.

Note that these controls are performed when the load applied to the workbench 22 becomes excessive, and an alarm is given to the operator by the alarm indicator lamp 82 and the alarm buzzer 84.

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

The alarm buzzer 84 and solenoid valve 85 are alarm control circuits.
The alarm control circuit 30 is provided externally with respect to 30, and an address decoder 49 is provided in the alarm control circuit 30 to perform chip selection and the like.

The present embodiment is configured as described above, and its operation will be described below.

Each value FW (load applied to the workbench 22), RP as shown in Fig. 2
(Distance from the fulcrum of boom 12 to the center of gravity of work table 22), RW
(Distance from the fulcrum of boom 12 to the center of gravity of heavy object 26), FP
(Body 22 own weight), R (horizontal length when boom 12 is raised or lowered, that is, working radius of boom), RB (distance from fulcrum of boom 12 to center of gravity of boom 12), BL (boom 12 length ), FB (the weight of the boom 12), and θ _B (the hoisting angle of the boom 12) are set, the hydraulic actuator 14
The moment EMOM applied to the L and 14R from the boom 12 is expressed as EMOM = RW ・ FW + RP ・ FP + RB ・ FB.

The moment LMOM applied to the hydraulic actuators 24L and 24R from the workbench 22 is represented by LMOM = (R−RW) · FW + (R−RP) · FP.

When added as a result of subtraction considering the directions of those moments EMOM and LMOM, EMOM + LMOM = RW ・ FW + RP ・ FP + RB ・ FB + (R−RW) ・ FW + (R−RP) ・ FP = R ・ FW + R ・ FP + RB・ FB becomes (1), so EMOM + LMOM = R · (FW + FP) + RB · FB (2) is obtained.

As understood from the formula (2), the heavy object 26 is a workbench.
It is possible to always handle 22 as being positioned at the right end shown by the broken line in FIG.

Further, if the equation (1) is modified, R · FW = EMOM + LMOM−R · FP−RB · FB, so the value FW is expressed by the following equation (3).

FW = {EMOM + LMOM- (R · FP + RB · FB)} / R (3) Then, in the above formula (3), EMOM is the moment response value and moment arm detected by the moment detectors 16L and 16R (this moment The arm is a function having the undulation angle of the boom 12 as a variable, and the arithmetic expression of the function can be calculated as an integrated value with () stored in the program ROM 34 in advance).

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

Further, of the value (R · FP + RB · FB) and the value R, the value R is calculated based on both output values from the boom hoisting angle detector 18 and the boom length detector 20, and the value FP and the value FB are constants. Is.

Further, the value RB is a function whose variables are the undulation angle and the length of the boom 12, and the arithmetic expression of the function is previously stored in the program ROM 3
The value RB is stored in 4, so the boom undulation angle detector 1
It can be calculated based on both output values from 8 and the boom length detector 20.

From the above explanation, the load FW to be measured is the moment detector.
16L, 16R, 28L, 28R, boom hoisting angle detector 18, boom length detector 20 is a function with each value detected as a variable, so the load FW can be calculated based on the output value of each detector. It is understood that there is.

FIG. 5 schematically shows the aerial work vehicle of FIG. 2, and as shown in the figure, the values M1 (EMOM), M2 (LMOM), x (R
When W), y (R-RW), FW, and θ (θ _B ) are determined,
The boom moment M1 detected by the moment detectors 16L and 16R is expressed by M1 = (boom own weight moment) + (work bench own weight moment) + FW · x, and the work bench moment M2 is M2 = (work bench own weight moment) ) + FW · y

Therefore, the sum of those moments M1 and M2 is expressed as M1 + M2 = FW · (x + y) + (sum of self-weight moments) = FW · (boom length) · cosθ + (sum of self-weight moments). Length (B
L), the load FW of the heavy object 26 can always be accurately calculated from the boom hoisting angle θ regardless of the position.

When the workbench 22 extends rightward by the tip of the boom 12 as shown in FIG. 6, the moment M ₂ is in the opposite direction to the above, so M1 = moment of gravity (boom, workbench) + FW · x M2 = moment of gravity (workbench) + FW · y M1−M2 = FW (x−y) + (difference of moment of gravity) = FW · (boom length) · cosθ + (difference of moment of gravity) is established and Fig. 5 The load FW is required as in the case of.

In the alarm control circuit 30 of FIG. 4, the moment detectors 16L, 16R,
28L, 28R, boom up / down angle detector 18, boom length detector 20
The characteristic of the load FW as a function with the detected value of the variable as data is RO
It is prepared in advance on the table of M36, and as shown in FIG. 7, the CPU 32 uses the detected values to search and calculate the load FW from the table (steps 100 to 103).

That is, when the detection values from the respective detectors are input in step 100, in the next step 102, the average value of the detection values of the moment detector 16L and the moment detector 16R, and the moment detector. An average value of the detection value of 28L and the detection value of moment detector 28R is calculated.

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

Therefore, the load FW can be accurately obtained regardless of the position of the heavy object 26 on the work table 22 in the vehicle width direction.

When the load FW is obtained in this manner, whether or not the load FW is excessive is stored in advance as a limit value (boom
It is judged by comparing it with a function having the undulation angle and the length of 12 as variables) (step 104), and when it is excessive, the alarm indicator lamp 82 is turned on, the alarm buzzer 84 is sounded, and the solenoid valve 86 is also activated. Is driven (step
105).

Then, in the next step 106, the load FW is displayed on the numerical display 6
2. Displayed by the unit display 64.

As described above, in the present embodiment, when the heavy load 26 moves on the workbench 22 to any position in the front-rear direction and the width direction of the vehicle, the heavy load does not depend on the position.
The load FW of 26 is accurately measured.

Therefore, despite the moving position of the heavy load 26, the alarm indicator light
Workbench with 82, alarm buzzer 84, solenoid valve 86
It is possible to drive the load accurately with the load limit of 22, and therefore, it is possible to ensure extremely high safety.

(Effects) As can be understood from the above description, in the work platform load measuring apparatus for an aerial work vehicle according to the present invention, even when an operator or the like moves on the wide work platform in the longitudinal direction of the boom, the movement thereof does not occur. Accurately measure the load applied to the workbench regardless of position.

As a result, it is possible to properly limit the load on the workbench, and it is possible to ensure extremely high safety.

[Brief description of drawings]

FIG. 1 is a diagram for responding to complaints, FIG. 2 is a right side view of an aerial work vehicle, FIG. 3 is a front view of FIG. 2, and FIG. 4 is a constitutional explanation of an alarm control circuit for measuring a load applied to a workbench. FIG. 5, FIG. 5 and FIG. 6 are explanatory diagrams for explaining the calculation operation of the load applied to the work table, and FIG.
The figure is a flow chart for 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 22 ... Workbench, 26 ... Heavy load 30 ... Alarm Control circuit, 32 ... CPU 34 ... Program ROM, 36 ... Data ROM 38 ... Work RAM, 82 ... Alarm indicator 84 ... Alarm buzzer, 86 ... Solenoid valve 62 ... Numerical indicator, 64 ... Unit indicator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Bibliographic references Sho 56-74321 (JP, U)

Claims (2)

[Claims] 1. A boom moment detection for detecting a value in response to a moment applied from a boom to a hydraulic actuator interposed between a boom whose base end is rotatably supported by a base and a base. Means, a boom hoisting angle detecting means for detecting a hoisting angle of the boom, and a work table horizontal holding hydraulic actuator for horizontally holding the work table attached to the tip of the boom regardless of the hoisting motion of the boom. Workbench moment detecting means for detecting a value responding to a moment applied from the workbench, boom length detecting means for detecting a length of the boom, a value responding to the detected boom moment, a hoisting angle of the boom, and a workbench A workbench load calculating means for calculating a load applied to the workbench based on a value responding to the moment and the length of the boom. The means subtracts the value corresponding to the work platform moment from the value corresponding to the boom moment, and further subtracts the value corresponding to the moment acting around the boom undulation fulcrum based on the boom's own weight, and the result is divided by the boom working radius. A work platform load measuring device for an aerial work vehicle, wherein the load on the work platform is calculated by subtracting the weight of the work platform from the division result. 2. The boom moment detection means is provided for each of the boom up-and-down drive hydraulic actuators arranged on both sides of the boom, and the workbench moment detection means is arranged on each side of the boom. The workbench load measuring device for an aerial work vehicle according to claim 1, wherein each of the holding hydraulic actuators is provided.