JPH02154118A - Load weighing device - Google Patents

Abstract

PURPOSE:To obtain a high-accuracy device whose constitution is simple by detecting the change of the resistance value of an amorphous wire which receives the weight of an object to be weighed as tensile load. CONSTITUTION:When the object to be weighed 20 is placed on a pan 1, the weight thereof directly acts to a 1st amorphous wire 6 stretched between a supporting bar 2 and a main body 3 as the tensile load. Thus, the amorphous wire 6 elongates within an elastic range and its resistance value is changed. Off-balance occurs in the bridge circuit of a detection part 15 because of the change of the resistance value and potential difference occurs. The potential difference is amplified by a voltage amplification circuit 16 and inputted in a microcomputer 17. Then, the microcomputer 17 calculates the weight of the object to be weighed 20 based on the change of the potential difference and the load is displayed by a display LED 18.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a load weighing device used for kitchen or commercial pillars.

(Prior art) Conventionally, this type of load measuring device has an elastic body such as a beam to which a strain gauge is attached inside the main body, and the weight of the object to be weighed is directly applied to the elastic body to reduce the strain. There is a device that measures the load by converting it into the resistance change of a strain gauge.

(Problem M to be Solved by the Invention) However, this method requires high accuracy in processing the elastic body and attaching the strain gauge to the elastic body, and has the problem of being expensive. In addition, since the strain gauge has a large change in resistance value due to temperature change, that is, a large temperature coefficient, temperature correction is required at high temperatures, resulting in a problem of reduced measurement accuracy.

The present invention was made in view of such problems, and an object of the present invention is to provide a load measuring device with a simple structure and high accuracy.

(Means for Solving the Problems) As a result of various studies on the premise of simplifying the structure by directly applying a tensile load to the metal resistance wire, the present inventors found that such a metal resistance wire ■It has high tensile strength and can be made as thin as possible to withstand the load, ■It has a wide elastic deformation region, ■It has a small temperature coefficient of resistance, ■It has a large specific resistance, and ■It has a strain gauge that is sensitive to changes in resistance to elongation, that is, strain sensitivity. It has become clear that amorphous wire is the material that best meets this requirement.

Therefore, the load weighing device according to the present invention includes an amorphous wire that receives the weight of an object to be weighed as a tensile load, a detection section that detects a change in the resistance value of the amorphous wire, and a load measurement device that detects a load based on a signal from the detection section. The present invention is configured to include an arithmetic processing section that calculates the load, and a display processing section that displays the load calculated by the arithmetic processing section.

(Function) According to the above configuration, the weight of the object to be measured acts on the amorphous wire as a tensile load. This causes the amorphous wire to stretch and its resistance value to change. This change in resistance value is detected by the detection section, a load is calculated by the arithmetic processing section, and the load is displayed by the display processing section.

(Example) Next, one embodiment of the present invention will be described with reference to the accompanying drawings.

1 and 2 show a load weighing device according to the present invention, in which a support rod 2 protruding from the back surface of a saucer I is inserted into the main body 3 through a hole 4 provided on the top surface, and is inserted into the upper and lower parts of the main body 3. One end of the arm 5.5 is rotatably attached to the main body 3, and the other end of the arm 5.5 is rotatably attached to the main body 3, so that the arm 5.5 can be moved up and down.

The upper end of the first amorphous wire 6 is attached to the main body 3 via a coil spring 7, and the lower end is attached to the lower end of the support rod 2.

Further, in the support rod 2, a second amorphous wire 8, which is made of the same material and has the same wire diameter and length as the first amorphous wire 6, is attached near the first amorphous wire 6.
is installed.

A lower limiter 9 is attached to the back surface of the saucer l so as to be able to come into contact with the upper surface of the main body 3, and restricts the amount of descent of the saucer I. In addition, an upper limiter 10 is attached to the support rod 2.
is attached so as to be able to abut on the inner surface of the main body 3, and the amount of rise of the support rod 2 is regulated.

A display panel 11 is attached to the front surface of the main body 3, and an electronic circuit board 12 on which a weighing display circuit is formed is attached to the back surface thereof.

As shown in FIG. 3, the measurement display circuit includes a first amorphous wire 6 and a second amorphous wire 8 for temperature correction.
It is composed of a detection section 15 in which a bridge circuit is formed by resistors 13 and 14, a voltage amplification circuit 16, a microcomputer 17, and a display LED 18.

Said 1st. The second amorphous wire 6.8 has a wire diameter of 12
It is 5 μm and 10 cm long, and the material is Co-Fe −
The composition of Cr-Si-B system is Co45.0, Fe23
．． 01Cr10.0, Si9.01B13.0 (at%
) (equivalent to AE-10 manufactured by Unitika Co., Ltd.),
The maximum tensile load used is 4 kg.

In addition, (Co75.0, Fe25.0)63.5, Cr12.
5, Si9.0, B13.0, Mo2.0 (Unitika (
(equivalent to AE-20) may also be used. Further, the wire rod is not limited to a wire rod having a circular cross section, but a wire rod having a rectangular cross section obtained by cutting a foil material may also be used.

FIG. 4 shows the above-mentioned 1. The relationship between the load and resistance of the second amorphous wire 6.8 is shown. According to this, the load and resistance are in a proportional relationship, and no hysteresis is observed during loading and unloading.

In the load cell 1 device having the above configuration, the object to be measured 2
0 is placed on the tray 1, its weight 1 acts directly on the first amorphous wire 6 stretched between the support rod 2 and the main body 3 as a tensile load. As a result, the first amorphous wire 6 stretches within its elastic range and its resistance value changes.

This change in resistance value disrupts the balance of the bridge circuit of the detection section 15 shown in FIG. 3, resulting in a potential difference. This potential difference is amplified by the voltage amplification circuit 16 and input to the microcomputer 17. And microcomputer 1
7 calculates the load of the object to be measured 20 based on the change in the potential difference, and this load is displayed by the display LED 18.

The weighing range of this load weighing device is approximately 2 kg, but if a load larger than this is applied, the coil spring 7 will stretch, the support rod 2 will descend, and the lower limiter 9 will come into contact with the container body 3 and stop. The first amorphous wire 6 is never cut.

In addition, when the main body 3 is lifted by holding the saucer 1 or the main body 3 falls down, the upper limiter IO
The support rod 2 does not move unnecessarily.

(Effects of the Invention) As is clear from the above description, according to the present invention, an inexpensive amorphous wire is used, and the amorphous wire itself is an elastic body that receives a direct tensile load, so the structure is simple and the manufacturing process is easy. In this case, parts accuracy and installation accuracy are not required, and it can be produced at low cost.

Furthermore, since it uses an amorphous wire that has a low temperature coefficient and can withstand high temperatures, it can be used with high accuracy even in electric heating devices such as rice cookers.

Furthermore, since amorphous wire with good corrosion resistance is used, it has the effect of stabilizing measurement characteristics over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the load weighing device according to the present invention, Fig. 2 is a sectional view taken along the il line in Fig. 1, Fig. 3 is an electric circuit diagram of the load weighing device, and Fig. 4 is a change in the load of the amorphous wire. FIG. 6... First amorphous wire, 15... Detection section,
17... Microcomputer, 18... Display LED (display processing section), 20... Object to be measured, 21... Arithmetic processing section. Patent Applicant Zojirushi Mapobin Co., Ltd. Agent Patent Attorney Haka Aoyama (Figure 3 + mu) No. 47 (9r)

Claims (1)

[Claims] (1) an amorphous wire that receives the weight of the object to be weighed as a tensile load, a detection section that detects a change in the resistance value of the amorphous wire, and an arithmetic processing section that calculates the load based on a signal from the detection section; A load weighing device comprising: a display processing section that displays the load calculated by the calculation processing section.