JPS60114718A - Electrostatic capacity type scale - Google Patents

Abstract

PURPOSE:To implement a compact configuration and a thin type, by insulating a movable electrode plate, fixing it to the central part of a beam shaped strain yielding body, insulating a fixed electrode plate, fixing it to both ends of the beam shaped strain yielding body so that the plate becomes in parallel with the movable electrode plate and a unitary body is formed. CONSTITUTION:When a weight is loaded on a cover 29, the weight is transmitted to the central part of a beam shaped strain yielding body 11. A small amount of strain is yielded from the central part, with a sharp edge part 10b as a supporting point. Then, a fixed movable electrode plate 15 is vertically lowered, with a parallel state being kept with respect to a fixed electrode plate 19. A gap g' is formed between the fixed electrode plate 19 and the movable electrode plate 15. The amount of change in electrostatic capacity generated in the gap g' between the fixed electrode plate 19 and the movable electrode plate 15 is converted into the weight by an electronic member and displayed.

Description

[Detailed description of the invention] The present invention relates to capacitive scales.

Conventional capacitive scales generally have the following structure.

In the first example, as shown in FIG. 1, a long lever 2 as a first lever and a lever (not shown) as a second lever are combined on a fulcrum 1 and wound around the end 2a of a long lever 112 as a first lever. By connecting the springs 3, the weight of the weight ff1W1 loaded on the long machine 2 is changed to the displacement of the coiled spring 3, and this displacement is applied to the point 2 of the long machine 2.
b, and this is interlocked with one movable electrode plate 4 of the electrode plate composed of two electrode plates, and the g between these two electrode plates is detected.
A capacitive scale that converts the capacitance generated in 1 into a weight value and displays the weight.

In the second example, as shown in Fig. 2, there is a long lever ll2' as the first lever on the fulcrum 1', and a tankan (not shown) as the second lever.
As a third example, although not shown, there is a platform scale in which the straining body 5 of the donkey pal mechanism is connected to the end 2a of the long machine 2' as a first lever. One side of the strain body 5 is fixed to a base, and the other side has a scale or the like with a plate fixed as a load receiver, but in the scale in the first example, the displacement of the movable electrode plate 4 is caused by parallel motion. Instead, it becomes a scissor-like movement, and the change in capacitance with respect to the load is not linear, resulting in poor accuracy.In particular, in order to guarantee the quality of the melon, it is necessary to increase the area of the two electrode plates. However, as the shape of the electrode plate increases, the weight also increases.

In the second example, the precision is high, but the structure around the strain-generating body 5 is complicated, the strain-generating body itself is expensive, and the assembly cost is high.

In the third example (not shown), both the substrate and the load receiving plate require rigidity, and the shape of the strain-generating body itself becomes large and heavy, resulting in extremely high cost.

Based on the above-mentioned drawbacks, the present invention aims to provide a new weighing scale that forms an extremely simple strain-generating body without using a coiled spring, can be made lightweight and thin, and is easy to assemble and inexpensive.

Examples below are 3-a, 3-b'+4-a,
This will be explained in detail based on FIGS. 4-b and 59.

Reference numeral 10 denotes a support for a beam-like flexure body to be described later. This support 10 is made of a substantially thick metal material by bending both ends of an elongated plate, cutting off the bent piece 10a in the shape of an opening, and providing a sharp edge portion 10b on both sides of the bottom. The rib 10c is installed to make it a reinforced and rigid body.

11 is a beam-like strain body. This beam-like strain body 11 is made of a thick piece of steel having spring properties and is formed into an elongated shape. Both ends are slightly narrow, and a narrow part 11a and a stopper hole 11b are provided on both sides of the middle part. The elastic body 12 has a hanging hole 12a molded with a plate spring, and a fixing plate 13 is attached to the fixing hole 11d, and a rivet 14 or It is fixed with screws.

Reference numeral 15 denotes one of the two electrode plates, which is a relatively small movable electrode plate. This movable electrode plate 15 has a central portion 15
While insulating a with the upper and lower insulation plates 16.17, tighten the set screw 1.
8, it is fixed to a stop hole 11d' provided at the center of the beam-like strain body 11 via a stop hole 15b.

19 is the other electrode plate, which is a fixed electrode plate. A clearance hole 19a for the set screw 18 is provided in the center of the fixed electrode plate 19, and a stop hole Th19b is provided at both ends. One piece 23a of a flexible elastic body 23 molded from a plate spring or the like is fixed by contacting the receiving plate 24 with -22 or a screw, and the other piece 23b of this elastic body 23 is attached to the beam-like strain body 1.
1, and fix it with a rivet 26 or a screw via a stop plate 25. At this time, the movable electrode plate 15 and the fixed electrode plate 19 have their centers coincident with each other so that they are parallel to each other, and the two electrode plates 15 and 19 and the beam-shaped strain body 11 are integrated.

The integrated beam-like strain body 11 has narrow width portions 1 at both ends.
1a can be placed on the sharp edge portion 10b provided on the support 10, and can be attached to and removed from the support 10.

27 is a base, 28 is a stack, and 29 is a cover.

Base edges 30, which are fulcrums, are provided at the four corners of the base 27, a support 10 is fixed at the center, and a beam on which the two electrode plates 15 and 19 are arranged is mounted on the support 10. A state strain body 11 is placed. At this time, the elastic body 12
The directions of the hanging holes 12a provided in the base 27 are respectively directed toward the base edges 30, which are fulcrums provided at the four corners of the base 27.

The stacking rod 28 has four pieces of the same shape, and has a fulcrum engaging portion 28a.
, a force point engaging part 28b, and an action point engaging part 28c, and the respective fulcrum engaging parts 28a are engaged with base edges 30, which are fulcrums at the four corners provided on the base 27, to achieve a point of action engagement. The portion 28c is engaged with the hanging hole 12a of the elastic body 12.

The cover 29 is a part on which weight is loaded, and the base 27
Similarly, cover edges 31, which are the focus points, are fixed at the four corners,
This cover edge 31 is freely engaged with each of the force point engagement portions 28b provided on the stacking rod 28 described above via an intermediate edge 32.

When weight is loaded on the cover 29 with the above configuration, this weight is concentrated on the action point engagement portion 28c of the stack rod 28 from four directions with a low ratio of the stack rod 28, and is transmitted through the elastic body 12 to the beam-like The beam-like strain body 11 is transmitted to the center of the strain body 11, and the beam-like strain body 11
Using the sharp edge portion 10b provided at 0 as a fulcrum, a slight distortion occurs from the center in proportion to the 1ffl.

When the beam-like flexure body 11 is strained, this beam-like flexure body 11
The movable electrode plate 15 fixed to the fixed electrode plate 19 descends vertically while remaining parallel to the fixed electrode plate 19.
A gap g' is formed between the movable electrode plate 15 and the movable electrode plate 15. At this time, the elastic body 12 has a mechanical precision or a base edge 30, for example.
The fulcrum engagement part 2 is due to deviation due to the dimensional accuracy and dimensional accuracy.
8a is absorbed and corrected, and the low ratio of the stacking rod 28 is always kept constant. Further, the flexible elastic body 23 absorbs the warping of the fixed electrode plate 19 caused by the distortion caused by the load on the beam-like flexural body 11, and always maintains the fixed electrode plate 19 in a flat state. In this way, the fixed electrode plate 19 and the movable electrode plate 1! ), the amount of change in capacitance that occurs in the gap 0' between the two is converted into weight using an electronic component, and the heavy lifting display is covered.

As mentioned above, the strain body for detecting weight is usually made of general steel material, and is small and thin, so as mentioned at the beginning, it is possible to provide a small, lightweight, and thin scale. 15. Sensor part and beam-like strain body 11 composed of 19
The parts are integrated, and the integrated beam-like flexure body 11 can be attached to and detached from the support body 10, so the number of assembled T is reduced, which leads to improved productivity. Since it automatically absorbs and corrects the bias of the j-method, extra distortion, etc., it has various effects such as being able to provide a scale with higher accuracy.

[Brief explanation of drawings]

FIG. 1 is a simplified side view of a first example of conventional implantation. FIG. 2 is a simplified side view of a second example of the conventional configuration. The following are drawings in the present invention. Figure 3-a is a plan view of the combined support body 10 and beam-like strain body 11, and Figure 3-b is a side view of Figure 3-a with the base 21 and cover 29 added. . Figure 4-a is a plan view of the support 10, the fixed electrode plate 19, and the movable electrode plate 15 attached to the beam-like flexure element 11, and Figure 4-b is a side view of Figure 4-a. be. FIG. 5 is an exploded perspective view of the waist. 10... Support body 10b... Sharp blade part 11...
Beam-like strain body 15...Movable electrode plate 19...Fixed electrode plate 12, 23...Elastic body.

Claims (1)

[Claims] 1) In a capacitive scale, a support, a beam-shaped flexural body, and two electrode plates are provided, and one movable electrode plate 15 is connected to the beam-shaped flexural body. is insulated and fixed to the center of the other fixed electrode plate 19.
are insulated and fixed to both ends of the beam-like strain body through an elastic body 23 so as to be parallel to the one movable electrode plate 15, and are integrally formed. 2) The capacitive scale according to claim 1, wherein the support has sharp blades at both ends, and the support and the beam-like flexure body are detachable. 3) The beam-like flexure body 3. The capacitive scale according to claim 1, wherein the load is transmitted to the elastic body 12 via an elastic body 12 fixed to the beam-like flexure body.