JPH11344389A - Strain detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and accurately detect a load by inserting a load cell into a circular hole provided for a member to be measured. SOLUTION: Load cells 3d to 3f are respectively inserted into circular holes 6 provided on a base 5, and their annular contact parts are respectively brought into close contact with inner walls of the holes 6. When a load of a crane or the like is applied to the base 5, the base 5 is deformed corresponding to the change of the load, and hence the holes 6 are deformed. Thus, the cells 3d to 3f are distorted corresponding to the deformations of the walls. Strain amounts of the respective cells are taken out as electric amounts via output cables 4a to 4d connected to the respective cells. When the electric amounts are converted into load weights, the change state of the load applied to the base 5 can be accurately detected. Thus, the danger of overloading can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a distortion generated in an inner wall of a circular hole of a member to be measured, in which a load cell portion is formed so as to be inserted into the circular hole, and the distortion of the inner wall of the circular hole is detected. Further, the present invention relates to a strain detecting device for calculating a load from the amount of strain and measuring a load applied to the member to be measured.

[0002]

2. Description of the Related Art Conventionally, a load cell is interposed between a base supporting a machine or the like and a base on a foundation to change a change in load applied to the base into a change in strain of the load cell. The load was calculated and the change in the load applied to the machine was detected.
In addition, in order to detect the load of the plate member for load measurement,
An invention in which a strain gauge is attached to a hole of a plate-like member is known (Japanese Patent Application Laid-Open No. 9-311084).

[0003]

The above-mentioned conventional load cell is mainly interposed between the base and the support, and therefore, there is a problem in that the entire apparatus becomes higher only by installing the support. In addition, when a horizontal sliding force is applied to the support, the load cell sandwiched between the support and the base may be broken (for example, a torsional force is applied under a strong pressurized state).

[0004] Further, in the invention in which a strain gauge is attached to a hole of a plate-shaped member, there are severe restrictions in relation to a bolt hole.
There is a problem that cannot be applied to load detection of various machines.

[0005]

SUMMARY OF THE INVENTION The present invention has developed a load cell in which a circular hole is provided in a member to be measured (for example, a board supporting a load), and the load cell is attached to a circular carrier that can be inserted into the circular hole. The load cell is fitted into the circular hole of the member to be measured, and the load can be measured by the distortion of the circular hole, thereby solving the above-mentioned conventional problems.

In other words, the present invention provides a method for dividing a circular carrier into a plurality of parts in the axial direction, attaching a load cell to each of the divided parts and inserting the load cell into a circular hole of a member to be measured. An annular contact portion protrudes from the outer wall of the distal end of the load cell, a mounting plate is fixed to the base end side of the load cell, and an output cable is connected to each of the load cells. The contact portion is an annular ridge having an arc-shaped cross section. In another invention, the circular carrier is obtained by attaching a load cell to a cylinder or cylinder divided into six equal parts,
The holding cylinder is fitted to the base end side of the circular carrier, and the end surface of the holding cylinder is fixed to the mounting plate by abutting on the mounting plate to fix the load cell to the mounting plate.

The circular carrier (including the columnar carrier and the cylindrical carrier) of the present invention has its tip divided into a plurality of parts in the axial direction. Therefore, when a load is applied to the member to be measured, the circular hole is distorted.
Since the load cell attached to the circular carrier is distorted in response to the distortion, if the amount of the distortion is detected and the load is calculated, the accurate load applied to the member to be measured can be measured. In the present invention, since the distortion over the entire circumference of the circular hole can be detected, unlike the case of detecting only a part of the distortion of the circular hole, even if there is a deviation with respect to the load transmission of the measured member, There is no danger of erroneous measurement of the authentic load due to the deviation. For example, when a circular hole is provided in a base such as a crane and the load cell of the present invention is set in the circular hole, the load applied to the contact portion between the crane and the base changes depending on the direction and angle of the arm of the crane, Depending on the distance and the fixing means with respect to the fixing portion of the base, although the distortion of the circular hole is not always equal, the distortion of the circumferential wall of the circular hole is detected, and a plurality of circular holes are provided, and a plurality of load cells are provided. By setting, it is possible to detect the change in distortion of each part due to the change in load, so
If the correction is made based on the numerical value of the preliminary measurement (preliminarily measuring a change in strain due to a known load in advance), the load can be accurately detected, and harm or the like due to excessive load can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is intended to divide a tip portion of a circular carrier into a plurality of portions in an axial direction, attach a load cell to each of the divided portions, and insert the load cells into a circular hole of a member to be measured. An annular contact portion protrudes from an outer wall of a distal end portion of a circular carrier, a mounting plate is fixed to a base end side of the circular carrier, and an output cable is connected to each of the load cells.

[0009] A load cell is attached to the outer or inner surface of the circular carrier. In short, the object is achieved if the amount of distortion of the inner peripheral wall of the circular hole for setting the load cell can be accurately detected. Therefore, it is sufficient if a plurality of slits are provided, but it is preferable to divide the circular carrier into four or more divisions in order to accurately detect the amount of distortion from up, down, left, and right.

According to the present invention, since the load cell is divided into a plurality of parts, even if the distortion of the inner wall of the circular hole to be set is unequal depending on the position, the total distortion amount obtained by integrating the distortion of each part is as described above. This is considered to be proportional to the total energy of deformation of the inner wall of the circular hole. Therefore, if the change in the amount of strain in the circular hole due to the change in the known load is measured in each part and the conversion value (correction value) from the amount of strain to the load is obtained, the change in the amount of strain due to the unknown load can be calculated. The change of the unknown load can be accurately calculated.

[0011]

An embodiment of the present invention will be described with reference to the drawings.

The tip of the columnar carrier 1 is divided into six equal parts in parallel with the axial direction into divided parts 2a, 2b, 2c, 2d, 2e, 2f, and the load cells 3a, 3b, 3c, 3d,
3e, 3f attached, output cable 4 to each load cell
a, 4b, 4c, 4d, 4e, and 4f are connected (FIG. 4,
5, 6). A member to be measured (for example, a platform on which a crane or the like is placed,
) Is provided so as to protrude in close contact with the inner wall of the circular hole 6). A strain detecting device is fitted and fixed to the base end side of the columnar carrier 1 (fixed with screws 8), and the end surface of the holding cylinder 7 is fixed in contact with the mounting plate 9 (fixed with screws 10). 12 (FIG. 1,
2, 3). In FIG. 2, reference numeral 14 denotes a mounting hole provided in the mounting plate 9. In the above-described embodiment, the load cell is adhered to the columnar carrier 1. However, the same applies to the case where the load cell is adhered to the inner wall of each divided portion of the cylindrical carrier 1a as shown in FIG.

A load cell is inserted into a circular hole 6 provided in the base 5 of the distortion detecting device 12 and its annular contact portion 11 is inserted.
Is brought into close contact with the inner wall of the circular hole 6 (FIG. 1). In the above, when the load W of the crane 13 is applied to the base 5, the base 5
Is deformed in response to the change in the load W, so that the circular hole 6
The load cells 3a, 3b, 3c, 3d, 3e, and 3f are distorted in accordance with the deformation of the inner wall of the circular hole 6 (FIG. 9).
Therefore, each of the load cells 3a, 3b, 3c, 3d, 3e, 3
If the amount of strain f is taken out as an electric quantity and converted into a load, the fluctuation state of the load applied to the base can be accurately detected. Can be prevented from occurring.

[0014]

According to the present invention, since the load cell can be set in the circular hole, a circular hole having a predetermined size is provided in the member to be measured, and the load cell is set easily and securely. Has the effect of being able to detect

Most conventional load cells are provided between a base and a support or adopt a set method unique to each machine. Therefore, an installation place for a machine and the like by the base and the support is required, and the whole is high. However, the load cell may be damaged, or a specific load cell may be required for each machine. However, if the present invention is used, it can be applied to almost any machine. There are various effects such as easy setting of the machine.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment of the present invention.

FIG. 2 is a right side view of the same.

FIG. 3 is a left side view of the same.

FIG. 4 is a left side view of the load cell.

FIG. 5 is a sectional view taken along the line AA in FIG. 4;

FIG. 6 is a right side view of the load cell.

FIG. 7 is a partial cross-sectional view of another embodiment.

FIG. 8 is an explanatory view showing an attached state.

FIG. 9 is a partial sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Columnar carrier 2a, 2b, 2c, 2d, 2e, 2f Division part 3a, 3b, 3c, 3d, 3e, 3f Load cell 4a, 4b, 4c, 4d, 4e, 4f Output cable 5 Base 6 Circular hole 7 Holding cylinder 8, 10 Screw 9 Mounting plate 11 Annular contact part 12 Strain detector 13 Crane, etc. 14 Mounting hole

Claims (4)

[Claims] An end portion of the circular carrier is divided into a plurality of portions in the axial direction, a load cell is attached to each of the divided portions, and inserted into a circular hole of a member to be measured. A distortion detecting device, wherein an annular contact portion protrudes from an outer wall, a mounting plate is fixed to a base end side of the load cell, and an output cable is connected to each of the load cells. 2. The distortion detecting device according to claim 1, wherein the annular contact portion is an annular ridge having an arc-shaped cross section. 3. The distortion detecting device according to claim 1, wherein the circular carrier has a load cell attached to a column or cylinder divided into six equal parts. 4. A holding cylinder is fitted to the base end of the circular carrier,
2. The distortion detecting device according to claim 1, wherein an end surface of the holding cylinder is fixedly abutted on a mounting plate to fix the circular carrier and the mounting plate.