JPS63205522A - Live load detector for workbench of high-place working vehicle - Google Patents

Abstract

PURPOSE:To accurately detect the live load on a workbench regardless of its loading position by providing strain detectors to the workbench at two front and rear separate positions and detecting a value according to the bending moment at the two positions due to variations in the load of and loading position on the workbench. CONSTITUTION:Assuming that an optional live load is placed on the workbench 4 which is moment arm length (x) away from a strain detector 11 in a figure (a), the bending moment at the position of the strain detector 11 is denoted as M1 and the bending moment at the position of a strain detector 10 at a distance (x) from the detector 11 is denoted as M2; and bending moment values based upon the weight components of the workbench 4 and a support frame 8 are denotes as M1' and M2', and they are stored in a storage device 12 in a figure (b). Then when a load is placed on the workbench 4 and strain signals from the detectors 10 and 11 are inputted to the storage device 12, bending moment values corresponding to the strain signals and the bending moment values based upon the weight components are outputted and processed by a computing element 13 to accurately detect the load weight W regardless of the loading position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a work platform load detection system 9 &
Regarding location.

(Prior Art and Problems) In an aerial work vehicle, a worker rides on the workbench and performs various tasks, and the load that can be loaded on the workbench is determined as the rated load. Therefore, it is necessary to determine whether the payload loaded on the workbench is within the rated load, but conventional aerial work vehicles generally do not have a means to detect the payload JIr. Met. In addition, even if this means is provided, the means is to place a plurality of load cells on the floor of the workbench, place a flat plate that spans the entire floor on top of the load cells, and calculate the load based on the total value of the loads acting on the load cells. Since this method was used to detect , the device became large-scale, and the rated load of the workbench was reduced by the amount of the flat plate i.

(Means for Solving the Problems of the Conventional Problems) This invention provides a device for detecting the live load of a work platform of an aerial work vehicle in two positions spaced apart from each other in the front and back relative to the work platform. a detection means for detecting a value corresponding to the bending moment at a second position whose bending moment changes due to a change in the load position; The above-mentioned problem f is solved by calculating the bending moment difference and dividing this bending moment difference by the moment arm length between the front and rear positions to obtain the live load.

(Function) With this configuration, when a live load is placed at an arbitrary position on the workbench, the detection means detects a value corresponding to the bending moment caused by this live load. The calculating means obtains the bending moment difference between the two positions based on the detection signal from the detecting means, and divides this bending moment difference by the moment arm length of the front 82-fold position to obtain the live load.

(Example) Next, the present invention will be explained in detail based on a specific example.

In Fig. 1, %A is an aerial work vehicle, 1 is a traveling base, 2 is a nine-swivel platform that is rotatably mounted on the traveling base L, and 3
is a boom whose base end is pivotally supported by a swivel base 2, and a workbench 4 is disposed at its tip via a support frame 8, which will be described later. Reference numeral 5 denotes a hoisting cylinder located between the poom 3 and the swivel base 2 to control the hoisting of the boom 3. Reference numerals 6 and 7 are leveling cylinders, and the up and down movement of the boom 3 is reflected in the expansion and contraction movement of the leveling cylinder 6 so that the work platform 4 always maintains a horizontal posture regardless of the up and down movement of the boom 3. The expansion and contraction motion is transmitted to the leveling cylinder 7. Reference numeral 8 denotes a support frame pivotally supported at the tip of the pool 3 via a bottle 9 pipe, and is connected to the work table 41! i
rSupport. This support frame 8 is provided with strain detectors 10 and 11 at two positions, front and rear, spaced apart from each other in the front and rear directions with respect to the workbench 4, separated by a distance t, for detecting strain occurring in the support frame 8. Reference numeral 12 denotes a storage device in which a bending moment corresponding to the strain generated in the strain detector 10.11 and a bending moment (described later) Mu', M, /2 are stored in advance.

Now, in FIG. 1, assuming that a live load W acts on the workbench 4 which is separated by moment arm length X from the strain detector 11, the bending moment at the position of φ detection ill is M
Bending moment at the location of IThM detector 10? M
-, and of the bending moment Mt, the bending moment due to the dead weight component of the workbench 4 and the support frame 8 is M*'
If the bending moment due to the weight component of the workbench 4 and the support frame 8 is f Me' in the above-mentioned song Me, then the bending moments M* and Me can be expressed by the following formulas, respectively.

Me: Ms' + W X X...
” (1) Me: 1B + W X (j + 1
) """ (2) Also, the private load wfi can be expressed by the following formula.

In the above equation (3), 1M1' and calm are constants, and after all, the live load W can be calculated if the bending moments (Mm and M-) are known.

Next, the procedure of the calculation will be explained.

When the distortion signal is input, the memory 12 stores the corresponding φ
The bending moment theory ′ and M, / based on the self-weight component are output together with Mu and Ms. These bending moments are input to the calculator 13, which calculates the load weight wf by calculating the above-mentioned equation (3). q1 means is formed.

The load W is displayed on the display 14. Incidentally, the bending moments M1 and M・ were each stored in a memory device, but since a certain relational expression holds between the bending moment and the bending moment, the bending moment was calculated based on the equation. It's okay.

Further, in the above embodiment, the strain detectors 10 and 11 provided on the support frame 8 detected values corresponding to the bending moment caused by the live load, but the leveling cylinder 7 carries the moment around the pin 9. A detector for detecting the load acting on the leveling cylinder 7 may be provided, and either one of the strain detectors 10 and 11 may be removed.

Next, the output value of the arithmetic unit 13 is input to a comparator (not shown), and the comparator compares the output value with the rated load value, and when the output value exceeds the rated load value M*', the workbench is 4 may be stopped. Alternatively, the difference between the detection results of the strain detector IO and the strain detector 11 may be determined, and a bending moment signal corresponding to this difference may be stored in the memory. Furthermore, in the above embodiments, the workbench was placed at the tip of a straight-extending boom, but the present invention can of course be applied to an arrangement where the workbench is placed at the tip of a retractable boom. . Also, the distortion detectors 10.11.

It may be provided at the base end of the boom 30, and in this case, the moment arm length between the rain detectors changes as the moment arm length between the strain detectors changes in accordance with changes in the boom undulation angle θ. In other words, the distance between the distortion detectors 10 and 11 should be multiplied by the coa and J values at the boom heave angle of 0.

In addition, if it is sufficient to detect and alarm only when the live load exceeds the rated load X, it is also possible to set the alarm at the rated load.

(Effects of the Invention) The present invention has the advantage that the load on five workbenches can be accurately detected regardless of the loading position, and the space of one workbench can be used effectively, so that the device does not become large-scale.

[Brief explanation of the drawing]

FIG. 1 is a side view of an aerial work vehicle implementing the present invention,
FIG. 2 is a block diagram showing one embodiment of the present invention. A: Aerial work vehicle, 4: Work platform.

Claims (1)

[Scope of Claims] A work platform load detection device for an aerial work vehicle equipped with a work platform whose working position can be arbitrarily changed via a boom, the work platform payload detection device being installed on the work platform. Detecting means for detecting values corresponding to the bending moments at two positions spaced apart from each other in the front and back, the bending moments of which change due to changes in the live load of the workbench and the live load position; The present invention is characterized by comprising calculation means for obtaining a bending moment difference between the two positions based on a detection signal from the detection means, and dividing this bending moment difference by a moment arm length between the front and rear two positions to obtain a live load. A work platform load detection device for aerial work vehicles.