JPH0358450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention converts the gap between two electrode plates, which are weight sensors, and converts the capacitance change or capacitance value generated in the gap into weight. Regarding capacitive electronic scales.

In conventional electronic scales of this type, one fixed electrode plate, which is the sensor, is fixed to the base, so the weighing cannot be done on an unstable floor, such as a soft surface such as a bench top. As a result, the scale sinks and the center of the base is pushed up, causing the base to become distorted. Along with this, the fixed electrode plate is distorted and the measuring spring is tilted, making the change in capacitance relative to the weight unstable (even under a constant load). When the base warped, the gap between the fixed electrode plate and the movable electrode plate changed), making accurate weight display difficult. The other movable electrode plate has one end freely pivoted to the base and the other end in contact with one end of a lever that moves up and down in response to a load, so that the fixed electrode plate and the movable electrode plate are arranged so as to face each other. Because the fixed electrode plate and the movable electrode plate are each fixed separately (Actual Report 17231-1982)
(No. Publication) The number of parts is large, and assembly is very troublesome, resulting in poor yield and not leading to improved productivity, and also tends to be expensive.

In order to solve the above-mentioned drawbacks, the present invention has been developed by assembling the fixed electrode plate and the movable electrode plate of the sensor into an integral structure, fixing the movable electrode plate to the lever, and deforming a part of the tip of the fixed electrode plate. To provide an electrostatic capacitance type electronic scale which provides an inclined piece with a tilted piece, makes the inclined piece free, corrects distortion with respect to the base, and displays accurate weight with as little error as possible even with respect to the distortion of the base. There is a particular thing.

Embodiments will be described in detail below with reference to the drawings. 1
is the base. Base edges 2, which serve as fulcrums, are erected at the four corners of the base 1.

3 is a long machine lever and 4 is a short machine lever.

The long machine rod 3 has a tip end fixed to a flat part 5a of a long-term fixing plate 5, which will be described later, and has a V-shape, and a rear end part 3.
a is engaged with the base edge 2.

The long machine fixing plate 5 is made of a thick metal plate with a stepped portion at the tip, a claw piece 5b and an escape hole 5c are provided at the tip of the stepped portion, and a hole 5d is provided in the flat portion 5a, as described above. The long machine lever 3 is fixed like that.

The short machine lever 4 has one end 4a engaged with the base edge 2, and the other end 4b suspended from the middle part of the long machine lever 3 via an engagement ring 6.

S is a capacitance type sensor composed of a movable electrode plate 7 and a fixed electrode plate 8, each of which is molded from a single conductive plate. The movable electrode plate 7 has a mounting hole 7a.
and a bearing piece 7b at one end, and the fixed electrode plate 8 has a tip partially deformed to provide an inclined piece 8a, and this inclined piece 8a is centered at the intersection O of the axis H of the metering spring and the base and will be explained later. It is inclined with a curve that is almost the same as the arc of radius R between the apexes Q of the convex portions of the insulating holder. A bearing piece 8b is provided at one end similarly to the movable electrode plate 7, and each bearing piece 7b, 8b
The insulating collars 9 and 10 are mounted on the shaft, and the fixed electrode plate 8 is rotatably mounted on the shaft 11 via the insulating collars 9 and 10 so that the fixed electrode plate 8 faces the movable electrode plate 7, and assembled. has an integral structure.

Movable electrode plate 7 of the sensor S having the above-mentioned integrated structure
The mounting hole 7a is a hole 5 provided in the long machine fixing plate 5.
It is insulated via upper and lower insulating rings 12 and 13, and fixed by caulking with rivets or the like 14.

Therefore, here, the long machine lever 3 fixed to the long machine fixing plate 5 and the movable electrode plate 7 and the fixed electrode plate 8, which are the sensors S fixed to the long machine lever 3, are assembled into integral parts. .

15 is a support frame. This support frame 15 is fixed to the base 1, and a support plate 16 is fixed to its upper part.A metering pull 17 is suspended from the support plate 16 via an adjustment nut 18, and the lower end 17a of this metering pull 17 is It is engaged and suspended between the claw piece 5b of the long machine fixing plate 5 and the escape hole 5c.

19 is an insulating holder. As shown in FIG. 3, this insulating holder 19 is an integrally molded product made of a resin material with an extremely low coefficient of friction, and includes a mounting hole 19a, a convex portion 19b, and a stopper portion 19c.
The mounting hole 19a is aligned and fixed to the support plate 16 so that the convex portion 19b is located on the center line P of the metering pull 17, and the above-described fixed electrode plate 8 is mounted on the convex portion 19b. The intermediate part of the inclined piece 8a provided in the slanted piece 8a is placed and abutted in a free state,
Further, the stopper portion 1 is provided on the upper part of this inclined piece 8a.
9c is positioned to prevent the fixed electrode plate 8 from coming off due to vibration or impact of the scale. Furthermore, insulation holder 1
9 may be attached not only to the support plate 16 but also to a separate body (not shown) provided on the base 1 and fixed to this separate body.

20 is a cover. Cover edges 21 are fixed to the four corners of this cover 20, and these cover edges 21 are engaged with the force points f of the long machine lever 3 and short machine lever 4 via intermediate edges 22.

With the above configuration, when a load (body weight) is applied to the cover 20, the load is applied to the force point f of the long machine lever 3 and the short machine lever 4, and depending on the lever ratio, the long machine fixing plate 5 which is the point of action is applied.
The claw 5b of the long machine lever 3 moves down around the base edge 2 against the metering pull 17. Then, the tip of the movable electrode plate 7 descends together with the shaft 11, determines the gap G between the fixed electrode 8 and the movable electrode plate 7 corresponding to the load, and determines the amount of change in capacitance or capacitance generated in this gap G. The value is electrically converted into weight by the converting section 23 and displayed digitally on the display section 24.

In this way, the fixed electrode plate 8 is attached to the base 1 like the conventional product.
The fixed electrode plate 8 and the movable electrode plate 7 are assembled together as described above, and the movable electrode plate 7 is fixed to the long machine lever 4, and at the same time, an inclined piece 8a is provided at the tip of the fixed electrode plate 8. Since this inclined piece 8a is in free contact with the convex portion 19b of the insulating holder 19, the measurement surface is particularly unstable as mentioned at the beginning, for example, on a soft surface such as a jutan, etc. Even if the base 1 is slightly distorted, it will not directly distort the fixed electrode plate 8, and even if the center of the base is pushed up and curved, the abutting part of the inclined piece 8a (point Q) ) escapes and corrects accordingly, the gap G caused by the distortion of the base 1 hardly changes, making it possible to accurately display the weight relative to the load.

In addition, as mentioned above, the fixed electrode plate 8 and the movable electrode plate 7, which are the sensor S, are integrally attached to the long machine lever 4 and become a single component, so as mentioned at the beginning, the number of parts is small. Moreover, it is easy to assemble, has a good yield, and has many effects, such as improving productivity.

[Brief explanation of drawings]

Figure 1 is a plan view, Figure 2 is a sectional view along A-A',
FIG. 3 is an enlarged perspective view of the waist. 3... Long machine lever, 7... Movable electrode plate, 8... Fixed electrode plate, 8a... Inclined piece, 19... Insulating holder.

Claims (1)

[Scope of Claims] 1. In a capacitive electronic balance, a movable electrode plate is insulated and fixed to a long lever, and one end of the movable electrode plate and one end of the fixed electrode plate are connected to the movable electrode plate. It is insulated and attached to the shaft so that it can rotate freely, so that it faces opposite to the
A capacitance type electronic balance characterized in that the tip of a fixed electrode plate is brought into contact with an insulating holder fixed to a support plate. 2. The capacitive electronic balance according to claim 1, wherein the tip of the fixed electrode plate is provided with an inclined piece that is partially inclined.