JPH0469324B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to weighing devices such as platform scales, hoppers, tanks, and conveyors that use a plurality of multi-beam type load cells.

[Prior art]

Ordinary beam type load cell L for load measurement on platform scales, etc.
are often used. FIG. 1 is an explanatory diagram of such an ordinary beam-type load cell L, in which the dotted line shows the beam when no load is applied, and the solid line shows the displacement when the load is applied.

Such a beam-shaped load cell L applies a force to be measured perpendicular to the axis and a supporting force in the opposite direction to both ends of the beam 1, and the beam 1 is applied with a shearing force or a bending force in a direction perpendicular to the longitudinal axis of the beam 1. Displace. The above-mentioned force to be measured, that is, the load, is measured by detecting such strain by changing the electrical resistance of the strain gauge.

[The problem that the idea aims to solve]

However, if the beam 1 is displaced by a force perpendicular to its axis and its axis is tilted, the axial length l will not change, so
The original distance between the shaft ends in the horizontal direction is shortened by the displacement Δl, which corresponds to the inclination. For example, in the beam 1 shown in the first diagram, which has a thick hole 2 at both ends in the center, it is bilaterally symmetrical, strong at both ends, flexible at the middle, and supported at both ends A.
When a force P in the opposite direction is applied to the receiving end B, the beam 1 deforms into a parallelogram shape and the receiving end B moves in parallel,
The horizontal length l of the unloaded beam 1 becomes shorter in the longitudinal axis direction, that is, in the horizontal direction, by a displacement Δl in proportion to the load as the beam 1 deforms in the direction perpendicular to its axis.
If this displacement Δl in the axial direction is not free but regulated, the displacement in the direction perpendicular to the axis will also be interfered with, causing an error in force measurement.

For this reason, conventionally, when a large number of beam-type load cells were used on one load receiving plate, one end of each load cell L was slidable relative to the other end, and each load cell L was able to be freely displaced in the longitudinal beam axis direction. Not only was the mechanism complicated and expensive, but the receiving plate was unstable and vibrated, requiring a damper to stop the vibrations.

In addition, in such arrangement of beam-type load cells L, if the direction of the two beam-type load cells L from the supporting end A fixed to the support base 10 to the receiving end B is opposite, the direction of each beam-type load cell L is The forces that try to cause a displacement Δl in the longitudinal axis direction due to the load are opposed and balanced, so the displacement Δl becomes impossible, so the displacement Δl in the direction perpendicular to the axis is no longer proportional to the load,
Two beam-type load cells arranged in opposite directions will interfere with each other and cause errors as described above.

[Means to solve the problem]

The present invention eliminates such drawbacks and relates to an arrangement that prevents errors in the combination of multiple beam-type load cells.

When using multiple beam type load cells L ₁ , L ₂ ......
In order to prevent the above-mentioned error at low cost, each load cell is made of the same type and installed on the weighing device, and when installing it, from the load receiving end B which is fixed to the load receiving plate 12, to the supporting end which is fixed to the support base 10. The direction of the longitudinal axis toward A is set in a fixed direction, for example, parallel or in the same circumferential direction, so that the axis of each beam-type load cell L is allowed to freely perform the same displacement Δl in that direction.

[Effect]

As a result, when a load is applied, the load receiving plate 12 freely displaces only the displacement Δl of each beam-type load cell L ₁ , L _{2 .} . . , or rotates around its center by an angle corresponding to the displacement Δl. Type load cell L ₁ , L ₂
...Prevent mutual interference and eliminate errors.

〔Example〕

Preferred embodiments of the present invention will be described below with reference to the drawings.

As shown in the first figure, a support base 10 is fixed to the bottom surface of the support end A at one end of a plurality of beam-type load cells L, and a load receiving plate 12 is fixed to the top surface of the load receiving end B at the other end.
As shown in the figure, the four corners of the load receiving plate 12 are supported within the weighing frame 14, and the lines connecting the supporting end A and the load receiving end B are aligned in parallel directions to constitute a weighing device.

If the load receiving plate 12 is loaded, each of the beam-type load cells L ₁ and L ₂ will be displaced by Δl to the right in FIG. Displaced to. On the other hand, each beam-type load cell along the other side edge 4 of the load receiving plate 12
Similarly, L ₃ and L ₄ are also displaced by Δl to the right in FIG. 2, so the load receiving plate 12 is displaced by Δl in the direction of the support end A. Therefore, each beam type load cell L ₁ ,
L ₂ , L ₃ , and L ₄ do not interfere with each other and accurately detect the load.

FIG. 3 shows another embodiment of the invention. Each beam type load cell L ₁ , L ₂ , L ₃ , L ₄ is located at the center 0 of the receiving plate 12.
They are arranged in a clockwise or counterclockwise direction along the circumference of a radius R centered on . In this device, when a load is applied, the receiving plate 12 freely rotates clockwise or counterclockwise by an angle corresponding to the displacement Δl of the beam-type load cells, so that errors due to mutual interference between the beam-type load cells do not occur.

As described above, in the above embodiment, the beam type load cell L ₁ ,
This can be achieved by simply selecting the arrangement and direction when fixing L ₂ , L ₃ , and L ₄ to the receiving plate 12 and the support base 10, so it is very inexpensive and has great advantages.

However, in the device shown in FIG. 2 or 3, the load receiving end B of each beam-type load cell is placed at a fixed position at each corner of the load receiving plate 12, so the supporting ends A are two on the right side and the third on the right in FIG. In the figure, all of the parts protrude outside the area of the load receiving plate 12, and the area of the support base 10 is considerably larger than the load receiving plate 12. However, in each of the beam-type load cells L ₁ , L ₂ , L ₃ , and L ₄ , the displacement of the strain-receiving body, that is, the beam 1, is so small that it can be ignored, so the displacement l is, of course, very small.

In the above embodiment, each beam type load cell L ₁ , L ₂ ,
This is a device that eliminates errors in L ₃ and L ₄ , but the load cell is characterized by using hardened steel for its strain-receiving body, that is, beam 1, so that it can be measured while ignoring displacement. The displacement in the longitudinal axis direction is even more minute, and it does not have to be parallel to a strictly constant line or in the circumferential direction around the center of the receiving plate, or even if the axial direction is constant along the edge at each corner of the receiving plate 12. Errors are largely eliminated.

FIG. 4 shows an example of this, in which the receiving plate 12
Even if the receiving end B is placed at each corner of the receiving plate 12, and the supporting end A is placed along the contour line of the receiving plate 12 in a clockwise or counterclockwise direction, the receiving end B will not be reached from each supporting end A. Since the lines are arranged in the same circumferential direction, interference between the beam-type load cells L ₁ , L ₂ , L ₃ , and L ₄ can be largely prevented. According to this arrangement, it is not necessary to make the area of the support base 10 significantly larger than that of the load receiving plate 12.

That is, according to this device, even if the receiving end B is placed at the predetermined four corner positions of the receiving plate 12, the supporting end A will not go outside the area of the receiving plate 12 as in the embodiment shown in FIGS. 2 and 3. , therefore the supporting base 10
This prevents the disadvantage that the area of the load receiving plate 12 is significantly larger than that of the receiving plate 12, and the cost can be reduced.

In any of the cases shown in Figs _{. 2 ,} 3, and 4 above, the load receiving plate 12 and its outer side are arranged so that the receiving plate 12 can be freely displaced in the direction of the displacement Δl of each beam type load cell L ₁ , L 2 , L 3 , L ₄ . It is necessary that the displacement be unrestricted with sufficient play 16 between the scale frame frames 14. Further, in the above embodiment, an example is shown in which two or more load cells are used, but the same applies if two or more load cells are used.

〔Effect of the invention〕

As described above, in the present invention, each beam type load cell L ₁ ,
L ₂ . . . The direction from the load cell receiving end B to the supporting end A in the longitudinal axis direction is parallel to a fixed straight line or along a fixed circumferential direction around the center of the receiving plate 12, and each beam type load cell L ₁ , L ₂ ... Each beam type load cell L ₁ , L ₂ ... with free displacement in the longitudinal axis direction
Errors can be eliminated by preventing mutual interference between... Therefore, the beam type load cell L ₁ of the present invention,
According to the arrangement of L ₂ ..., each beam type load cell L ₁ ,
L ₂ ...There is no need to support the end so that it can slide or to take a complicated and expensive structure to suspend it, the structure is simple and inexpensive, and the receiving plate 12 is stable, and each beam type load cell L ₁ , L ₂ ... Since the directions of the longitudinal axes are the same, interference errors in the longitudinal axis direction of each beam type load cell L ₁ , L ₂ ... are prevented, so accuracy is improved.

[Brief explanation of the drawing]

In Figure 1, the dotted line is an elevation view of a beam-type load cell showing the displacement under no load, and the solid line is the displacement under load. Figure 2 is a plan view of an embodiment of a platform scale in which four beam-type load cells are arranged in a fixed direction. Figure 3 is a plan view of another embodiment of a platform scale in which four of these beam-type load cells are arranged in a fixed direction around the center of the load receiving plate, and Figure 4 is a plan view of another embodiment of the platform scale in which four of these beam-type load cells are arranged around the edge of the load receiving plate. FIG. 7 is a plan view of still another embodiment of a platform scale arranged in a certain direction along the FIG. L ₁ , L ₂ , L ₃ , L ₄ ...beam type load cell, 10...
...Supporting base, 12... Load receiving plate, A... Supporting end, B
...Consignment receiving end.

Claims (1)

[Claims] 1. Two or more beam-type load cells of the same type (L ₁ ,
L ₂ ...), one end of each beam-type load cell (L ₁ , L ₂ ...) is fixed to the support base 10, and the other end of the load cell is connected to the load receiving plate. 12, each beam-type load cell (L ₁ , L ₂ ...)
The lines from supporting _end A to receiving end _B of A weighing device using a multi-beam type load cell characterized by being able to contract by Δl. 2 Each of the above beam type load cells (L ₁ , L ₂ and L ₃ , L ₄ )
A weighing device using a multi-beam type load cell according to claim 1, wherein the lines connecting the supporting end A and the receiving end B of the load cell are arranged in parallel directions. 3. The multi-beam type load cell according to claim 1, wherein the lines connecting the supporting end A and the load receiving end B of each of the beam type load cells (L ₁ , L ₂ . . . ) are aligned in substantially the same circumferential direction. Weighing device using.