JPS6232324A - Multi-range load cell scale - Google Patents

Abstract

PURPOSE:To weigh with high accuracy in a weighing range of a high load by connecting a low weighing capacity load cell and a high weighing capacity load cell, and making the Roberval's center of this high weighing capacity load cell coincides roughly with a pan center. CONSTITUTION:A plate-shaped base 10 is provided horizontally, and on this base 10, one end of a high weighing capacity load cell (low weighing capacity LC) 12 is fixed through a spacer 11, and to the other end, one end of a low weighing capacity load cell (low weighing capacity LC) 14 is connected through a connecting frame 13. In such a state, as for a light object, a weighing result by the low weighing capacity LC 14 is displayed, and as for a heavy object, a weighing result by the high weighing capacity LC 12 is displayed. In such a case, as for the weighing result of the light and heavy objects, respectively, the minimum scale value is displayed in a different way. On the other hand, an angular moment generated in the high weighing capacity LC 12 to which a load has been applied is cancelled by a reverse angular moment generated in a pan 17. It is because the Roberval's center A coincides roughly with a pan center B. In this way, a weighing error of the high weighing capacity LC 12 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multi-range load cell scale that changes the minimum scale value in steps according to the magnitude of the load.

BACKGROUND OF THE INVENTION Conventionally, there has been a multi-range load cell scale in which the value of one scale in a display value, that is, the minimum scale value, is changed stepwise in accordance with the magnitude of load. Generally, in such a device, only one load cell is used, and the minimum scale value is changed according to the magnitude of the load by electrically switching the scale. However, multi-range load cell scales have a wide weighing range, and have the disadvantage that it is difficult to accurately weigh the entire weighing range with just one load cell. For example, from 0 (kg) to 35
(kg) using only one load cell, the load cell is required to have an accuracy of 1/35000. For a load cell with such precision, extremely high standards are required in the material of the load cell frame, the selection of strain gauges, the precision of the AD converter, etc. Therefore, it is expensive and has insufficient reliability, making it unsuitable for use in mass-produced multi-range load cell scales.

Therefore, in recent years, multi-range load cell scales that are capable of performing highly accurate weighing over the entire weighing range have been considered. An example of this is shown in FIG.

On the base 1 is a high-basis load cell 2 (hereinafter referred to as a high-basis LC).
One end of the highly popular ff1Lc2 is fixed, and one end of a low-basis load cell 3 (hereinafter referred to as low-basis LC) is connected to the other end of the highly popular ff1Lc2. And its low basis weight L
A saucer 4 is fixed to the other end of C3 and is arranged parallel to the base 1. Here, the high weighing capacity LC2 has a characteristic that enables highly accurate weighing when a large load is applied, and the low weighing capacity LC3 has a characteristic that enables highly accurate weighing when a small load is applied. has. Further, the high rating ff1Lc2 and the low rating 1tLc3 are arranged in the vertical direction.

With such a configuration, if the item placed on the tray 4 is heavy, the weighing result by the high scale LC2 is displayed, and if the item is light, the weighing result by the low scale MLC3 is displayed. Ru. On this occasion.

The minimum scale values are displayed differently for the weighing results based on the high weighing amount LC2 and the weighing results based on the low weighing amount LC3. On the other hand 5
The displayed weighing results are high weight LC2 and low weight LC3.
These are the measurement results within each specific range that allows highly accurate measurement. Therefore, highly accurate measurement can be performed over a wide range without using a particularly high-performance load cell.

However, in the above-mentioned one, since the high scale weight LC2 and the low scale weight tLc3 are arranged in the vertical direction, the height becomes high and the position of the saucer 4 is at a high position.

Therefore, it has been considered that the highly rated IfLLC2 and the low basis weight Lc3 are arranged in parallel in the horizontal direction. Examples of such a device are shown in FIGS. 5 and 6. Parts that are the same as those in FIG. 4 are designated by the same reference numerals and explanations will be omitted. Highly rated f L
C2 and low weight LC3 are arranged in parallel in the horizontal direction. And these highly acclaimed JfLC2 and low weight LC3
The connecting portion is connected by a connecting frame 5 which is a flat plate member formed into a predetermined shape.

In such a configuration, the load applied to the saucer 4 is applied to the low scale fi L C3, and is further applied to the high rating tLc2 via the connection frame 5. Here, highly accurate weighing is performed over a wide weighing range using the highly praised jtLc2 and the low weighing amount LC3. Moreover.

Due to the arrangement of the high basis weight f, C2 and the low basis weight LC3, the overall height is low and the position of the saucer 4 is at a low position.

Problems to be Solved by the Invention Since a load is applied to one end of the high basis weight LC2 and the low basis weight LC3, a rotational moment is generated when the load is applied. Therefore, a weighing error occurs in the high scale LC2 and the low scale ff1Lc3. This is because the load cell is deformed into an almost arcuate shape when a single rotational moment is generated, so that the expansion and contraction state of the strain gauge formed at the center of the load cell differs from the state assumed in advance.

On the other hand, the weighing errors of the highly rated 1Lc2 and the low weighing T-C3 are as follows:
It increases in proportion to the magnitude of the applied load. This is because as the load increases, the rotational moment also increases.

Therefore, it has the disadvantage that highly accurate measurement cannot be performed in a high load measurement range. This is especially inconvenient for devices that frequently perform heavy-load weighing.

The present invention was made in view of these points.

The purpose of the present invention is to obtain a multi-range load cell scale that can perform highly accurate weighing in a high load weighing range.

Means for Solving the Problems The present invention connects a low-basis load cell and a high-basis load cell, and makes the lobar center of the high-basis load cell substantially coincide with the center of the saucer to convert the saucer into a low-basis load cell or a high-basis load cell. Connected.

As for the objects to be weighed, the weighing results obtained by the low-basis load cell are displayed for light objects, and the weighing results obtained by the high-basis load cell are displayed for heavy objects. At this time, the minimum scale values are displayed differently for the weighing results for light and heavy weights.

On the other hand, the rotational moment generated in the high-basis load cell to which the cart is applied is the opposite rotational moment 1-
is canceled by This is because the center of the hull and the center of the saucer almost coincide. This reduces errors when using a high-basis load cell. Therefore, highly accurate weighing is performed in a high load weighing range.

Embodiment of the Invention An embodiment of the present invention will be described with reference to FIGS. 1 and 3. FIG. A flat board 10 is arranged horizontally. One end of a high-basis load cell 12 (hereinafter referred to as "high-basis LC") is fixed to this base 10'' via a spacer 11. One end of a low basis weight load cell 14 (hereinafter referred to as low basis weight LC) is connected to the other end of the high basis weight 1, C12 via a connection frame 13. Here, the quality rating tLc12 is a hard one with a small amount of distortion,
It has the characteristic of performing highly accurate measurement when a large load is applied. The low scale fLc 14 is a soft one with a large amount of strain, and has a characteristic that it can perform highly accurate weighing when a small load is applied. and.

Soku's highly rated 1Lc12 and low weight LC14 are.

The connecting frames 1 are arranged in parallel in the horizontal direction.
3 is a flat member having a shape capable of connecting the high basis weight Lc 12 and the low basis weight LC 14 arranged in this way.

Thus, a flat saucer 1 is connected to the free end 15 of the unconnected end of the low-basis LC 14 via a mounting body 16.
7 should be installed parallel to the base 10. The mounting body 16 is connected from the free end 15 to the J4+-C1
It has a crank-like shape bent in the direction of the center A of the Roberval 2. and.

The saucer 17 has a portion at the center B of the saucer that is attached to the mounting body 1.
It is fixed at 6. Therefore, the roberval center A and the saucer center B are arranged at almost the same position.

Strictly speaking, the saucer center B is located slightly closer to the free end 15 than the roberval center A.

Here, protrusions 18 are provided at the four corners of the lower surface of the saucer 17. Then, on the base 10, four corner strips 19 and flange 19 are placed at the positions where the protrusions 18 come into contact with each other.
is provided. A gap of a predetermined length is normally provided between the four corner stoppers 19 and the protrusion 18. Further, on the base 10, the high basis weight LC12
A central stopper 20 is also provided at the portion where the end on the tL side contacts when a load is applied. This central stopper 2
0 and the high basis weight LC12, there is usually a gap of a predetermined length.

On the other hand, a PC board 21 is attached to the high evaluation amount LC12 and the low weighing amount LC14. These PC boards 21 are attached to the lower end of the high weighing scale LC12, and are attached to the upper end of the low weighing scale ff1Lc14. Further, on the PC board 21, a circuit (not shown) is formed which is connected to the high basis weight Lc12 and the low basis weight LC14, respectively.

Here, FIG. 3 schematically shows the arrangement position of the PC board 21.

In such a configuration, an item (not shown) is weighed by placing the item on the tray 17. At this time, a load is applied to the saucer 17, and this load is transmitted to the low basis weight LC 14 via the attachment body 16. Furthermore, the connecting frame 13
It is transmitted to the high-basis LC12 via. Then, high-basis LC
12 and the low basis weight LC 14 are deformed, and the amount of deformation is electrically transmitted to the circuit of the PC board 21 connected to them.

In the circuit, it is selected by which load cell the weighing result is displayed.If the item is lightweight, the low scale is 1Lc.
14 is displayed.

On the other hand, if the item is heavy, the weighing result using the high weighing capacity LC12 is displayed. Therefore, measurement results that match the characteristics of each load cell are displayed, and highly accurate measurement is performed over a wide measurement range. Also, the value of the minimum scale to be displayed.

That is, the minimum scale value is different between the weighing result obtained by the low weighing capacity LC14 and the weighing result obtained by the high weighing capacity LC12. Specifically, the minimum scale value of the weighing result by the low scale ff1Lc 14 is smaller and displayed more precisely.

Here, the four corner stoppers 19 and the center stopper 20 prevent the two load cells from being deformed and damaged when a large load is suddenly applied to the receiving tray 17.

On the other hand, during weighing, a rotational moment is generated in the high weighing capacity LC12. Further, a rotational moment is also generated in the mounting body 1-6. These rotational moments are in opposite directions. Therefore, the two rotational moments l- cancel each other out, and in reality, no rotational moment is generated in either of them. As a result, the high basis weight LC 12 to which the load is applied is deformed into a predetermined state, and an ideal needle leaf state is obtained here.

Therefore, highly accurate measurement without measurement errors is performed in the measurement range of large loads. Note that the reason why the center B of the saucer is shifted toward the free end 15 side from the center A of the robot is to take into consideration that the mounting body 16 will bend and deform. That is, a member having a large amount of deformation is used for the mounting body 16 in order to reduce the weight, and if the center B of the saucer and the center A of the robot are made to coincide, the rotational moment thereof will become too large. Then, it becomes impossible to match the rotational moment generated in the low-basis LC 14, resulting in a measurement error. In order to prevent such a situation, the center B of the saucer is shifted toward the free end 15 side.

Also, since the PC board 21 is attached to the lower end of the high-basis LC12 and the upper end of the low-basis LC14,
The C plates 21 will no longer collide with each other. This reduces restrictions on the placement of the two load cells,
Parasitic on improving space efficiency.

In addition, in implementation, high reputation 1Lc12 and low scale iLc
14 may be arranged in a row in the downward direction. or.

Three or more load cells having different optimum weighing ranges may be arranged in any desired arrangement and used.

Effects of the Invention The present invention connects a low-basis load cell and a high-basis load cell, makes the lobar center of the high-basis load cell substantially coincide with the center of the saucer, and connects the saucer to the low-basis load cell or the high-basis load cell.
Since it is connected to a load cell, the rotational keyment that occurs in a high-basis load cell is canceled out, eliminating the measurement error of a high-basis load cell.Therefore, it has the effect of being able to carry out weighing at a high 61 degrees in the weighing range of large loads. .

[Brief explanation of the drawing]

FIG. 1 is an overall front view showing one embodiment of the present invention. Fig. 2 is a side view thereof, Fig. 3 is a front view schematically showing how the PC board is installed, Fig. 4 is a front view showing one conventional example, Fig. 5 is a front view showing another example; FIG. 6 is a perspective view of the connection frame. 12...High weighing capacity load cell, 14...Low weighing capacity load cell, 17...Saucer, A...Robbal center, B...
...Saucer center Applicant: Tokyo Electric Co., Ltd. 3" Bi

Claims (1)

[Claims] A multi-range characterized in that a low-basis load cell is connected to a high-basis load cell, and the lobar center of the high-basis load cell is substantially aligned with the center of the saucer, and the saucer is connected to the low-basis load cell or the high-basis load cell. Load cell scale.