JPS62261020A - Weight detector for electric platform weighing instrument - Google Patents

Abstract

PURPOSE:To constitute a weighing instrument body by a simple and inexpensive mechanism by horizontally supporting a rigid flat plate by three or more linear springs. CONSTITUTION:An weighing instrument body is constituted by a support mechanism K composed of a platform 1, an upper support mechanism A and a lower support mechanism B and a base plate 9. Since the mechanism K has arms 2 and 6 with thickest distal end portions, when the platform 1 and the plate 9 are mounted to the mechanism K to form a weighing instrument, a weight is distributed to weight points (1)-(4). Thus, when an object to be weighed is placed on the platform 1, springs 5 are deformed and rest in a condition wherein loads and the restoring force of the springs 5 balance each other. Relative positional relationships among planes formed by the weight points (1)-(4) and (1')-(4') and displacement- to-electricity converter mounting points 3 and 7 do not change and a conversion input to displacement-to-electricity converters 3 and 7 is determined in correspondence with the deformation of the springs 5 when loaded. Accordingly, the displacement of the platform 1 is equal to the arithmetic mean of the deformations of the springs 5. When the load is applied to a position apart from a center, the platform 1 is inclined. The inclination of the platform 1 produces no error in a weighed value and, even if the platform 1 is inclined, the displacement of the platform 1 can be neglected.

Description

【発明の詳細な説明】 本発明は電気式台バカリの載せ台支持方法と変位電気変
換器の最適配置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for supporting a stand of an electric stand base and an optimal arrangement of a displacement electric transducer.

従来台バカリは載せ台を３点以上の複数個の点で支持し
、計量物の重量を１組の分銅またはばねの復元力で平衡
させるよう１点に集合させるために、複数個のてこを組
み合わせた機構をもっている。第１図は従来の小型台バ
カリのてこ組みの一例を示しており、さお、長機、短機
は合体てこで、載せ台を支持しているＡ２、Ａ３はそれ
ぞれ紙面の前後に２点づつあり、載せ台は都合４点で支
持されている。荷重は力点Ｂ２において集合され、力は
連結棒を通じてさおＡ１Ｆ１Ｂ１の重点Ａ１に伝達され
る。Conventional platform support supports the platform at three or more points, and uses multiple levers to balance the weight of the object to be measured using a set of weights or the restoring force of a spring. It has a combined mechanism. Figure 1 shows an example of the lever assembly of a conventional small platform.The pole, long machine, and short machine are combined levers, and A2 and A3, which support the platform, each have two points on the front and back of the page. There are two, and the platform is supported at four points. The load is concentrated at the force point B2, and the force is transmitted through the connecting rod to the point A1 of the rod A1F1B1.

載せ台の長いものや大型の台バカリでは支持点も増え、
さらに複雑なてこ組みを必要とする。現状では電気式台
バカリもこれらてこ組み機構をもつものが多い。すなわ
ち一点Ｂ２に集合された力をコイルばね等で変位に変え
、さらに変位電気変換器により電気信号に変換している
。台バカリの計量誤差を小さく押えるには、安定した複
数個の支持点と力を正確に伝達するために、てこ組みの
製作調整に高度の熟練技術と手間を要する欠点があった
。また近年ハカリに電子技術の導入が進んでおり、載せ
台を３〜４個のロードセルによって直接支持するもの等
を除くと、体重計など薄型の台バカリでは、従来のてこ
組み機構により載せ台の安定支持と力の一点集中を図っ
たうえで変換器と結合して目的を達している。このこと
は機械式ハカリの機構と変換器、電子回路が共存するた
め、コストの低減を望めないし、電子化により小型、軽
量、高信頼性などの特長を得難い等の欠点があった。本
発明はこれら機械系から電気系に到る計測量の変換過程
を合理的に極限まで単純化する方法に関するものである
。For items with long platforms or large platform bases, the number of support points increases,
It requires a more complicated lever assembly. At present, many electric stand backers also have these lever mechanisms. That is, the force collected at one point B2 is converted into displacement by a coil spring or the like, and further converted into an electric signal by a displacement electric converter. In order to keep the measurement error of the stand back to a small level, there was a drawback that it required a high level of skill and effort to manufacture and adjust the lever assembly in order to use multiple stable support points and accurately transmit force. In addition, in recent years, electronic technology has been introduced to scales, and with the exception of those in which the platform is directly supported by 3 to 4 load cells, thin platform scales such as scales are supported by the conventional lever assembly mechanism. It achieves its purpose by providing stable support and concentrating force on one point, and then combining it with a transducer. This has drawbacks such as the coexistence of a mechanical peeling mechanism, a converter, and an electronic circuit, making it impossible to reduce costs, and making it difficult to obtain features such as small size, light weight, and high reliability due to electronicization. The present invention relates to a method for rationally simplifying the process of converting measured quantities from mechanical systems to electrical systems to the utmost.

本発明は前述の欠点を除去するためになされ、その目的
は簡明で安直な機構によりハカリ本体を構成せしめ、電
子回路との結合によって任意形状の薄型台バカリを実現
することにある。The present invention has been made in order to eliminate the above-mentioned drawbacks, and its purpose is to construct a cutter body using a simple and easy mechanism, and to realize a thin base cutter of any shape by combining it with an electronic circuit.

前記の目的を達成するため、任意形状の載せ台の合理的
支持方法と、変位電気変換器の配置を的確に行なうこと
ができる特徴がある。また本発明の他の特徴は変換器の
種類や電子回路の選択も自由な点にある。In order to achieve the above object, there is a feature that a rational support method for a platform having an arbitrary shape and an accurate arrangement of a displacement electric transducer are provided. Another feature of the present invention is that the type of converter and electronic circuit can be freely selected.

本発明の実施例を第２図によって説明する。第２図は簡
略化した斜視分解図、第３図は断面略図である。台バカ
リは載せ台１と基底板９および１、９に挟まれ収容され
る機構部によって構成される。An embodiment of the present invention will be explained with reference to FIG. FIG. 2 is a simplified perspective exploded view, and FIG. 3 is a schematic cross-sectional view. The base plate is constituted by a platform 1, a base plate 9, and a mechanism section housed between the base plate 1 and 1 and 9.

図においてコイルばね５およびねじ４、８は煩雑を避け
て２個づつしか描かれていないが、腕２および６に対応
してそれぞれ４個づつ必要である。In the figure, only two coil springs 5 and two screws 4 and 8 are shown to avoid complexity, but four each are required for arms 2 and 6.

また腕に設けられた取付ねじ穴（１）、（２）、（３）
、（４）および（１）′、（２）′、（３）′、（４）
′は上から見て反時計回りに４つの力点として配置され
ている。変位電気変換器は上部３および下部７に分解さ
れて描かれ、それぞれ上部支持機構２、３と下部支持機
構６、７に取り付けられているが、これら機構がばね５
を介してねじ４、８により結合されたとき１対となって
変換器を形成する。上部支持機構および下部支持機構が
一体となったものを支持機構と呼ぶことにする。本発明
による台バカリの機構は、載せ台、支持機構および基底
板の３部分よりなっている。There are also mounting screw holes (1), (2), (3) on the arm.
, (4) and (1)', (2)', (3)', (4)
' are arranged as four points of force in a counterclockwise direction when viewed from above. The displacement electrical transducer is shown disassembled into an upper part 3 and a lower part 7, each attached to an upper support mechanism 2, 3 and a lower support mechanism 6, 7, which are attached to a spring 5.
When connected by screws 4 and 8 through the cylindrical screws 4 and 8, they form a pair of transducers. The combination of the upper support mechanism and the lower support mechanism will be referred to as a support mechanism. The mechanism of the base plate according to the present invention consists of three parts: a platform, a support mechanism, and a base plate.

支持機構は第３図によって明らかなように、腕の先端部
がもっとも厚いので、載せ台１および基底板９を取り付
けハカリが形作られたとき、載せ台に計量物が載せられ
ると、重量Ｗは重点（１）、（２）、（３）、（４）に
分散される。支持機構の中央部はやや薄くなっているの
で、載せ台と支持機構および基底板と支持機構はそれぞ
れ（１）、（２）、（３）、（４）および（１）′、（
２）′、（３）′、（４）′点以外で接することはない
。つまり荷重は完全に４点に分散され、４点の荷重を加
算すれば載せ台上の計量物の重量と一致する。いま４個
のばねの変位量（伸縮）をｚｉ（ｉ＝１、２、３、４）
、分散した荷重Ｗｉ、計量物の重量をＷとすると、ばね
定数がｋとすると、Ｗｉ＝ｋｚｉなので…（１） となって、各ばねの変位ｚｉを計測し加算すれば、重量
Ｗを求めたことになる。例えば載せ台が正方形の場合、
つまり重点（１）、（２）、（３）、（４）および（１
）′、（２）′、（３）′、（４）′が正方形の頂点に
あり、正方形の中心に変位電気変換器が置かれ、中心か
ら各力点を結ぶ腕２、６は長さがすべて等しいとする。As shown in Figure 3, the support mechanism is thickest at the tip of the arm, so when the platform 1 and the base plate 9 are attached and the scale is formed, and an object to be weighed is placed on the platform, the weight W will be It is divided into emphasis (1), (2), (3), and (4). The central part of the support mechanism is slightly thinner, so the mounting table and support mechanism and the base plate and support mechanism are (1), (2), (3), (4) and (1)', (
They do not touch at points other than 2)', (3)', and (4)'. In other words, the load is completely distributed at four points, and adding the loads at the four points equals the weight of the object to be weighed on the platform. Now, the displacement (expansion and contraction) of the four springs is zi (i = 1, 2, 3, 4)
, if the distributed load Wi and the weight of the object to be weighed are W, and if the spring constant is k, Wi = kzi, so... (1) Then, by measuring and adding the displacement zi of each spring, the weight W can be found. That means that. For example, if the platform is square,
That is, emphasis (1), (2), (3), (4) and (1)
)', (2)', (3)', and (4)' are at the vertices of the square, the displacement electric transducer is placed at the center of the square, and the arms 2 and 6 connecting each force point from the center are Assume that all are equal.

ばね５はすべてばね定数ｋが等しく、この台バカリは水
平に設置されているとする。載せ台１に計量物を載せる
と、載荷点の位置に応じてばねはそれぞれ変位して、各
荷重とばねの復元力が平衡する点で静止する。支持機構
は充分大きな剛性をもつよう作られているから、重点（
１）、（２）、（３）、（４）および（１）′、（２）
′、（３）′、（４）′が形成する平面と、変位電気変
換器取付点３、６との相対的位置関係は変化しないので
、載荷時の各コイルばね変位に対応して変位電気変換器
３、６への変位入力は決まる。すなわち、本実施例にお
ける形状では、変換器入力変位は各コイルばね変位の相
加平均に等しい。It is assumed that all the springs 5 have the same spring constant k, and that the base plate is installed horizontally. When an object to be weighed is placed on the platform 1, the springs are displaced depending on the position of the loading point, and come to rest at a point where each load and the restoring force of the spring are balanced. The support mechanism is made to have sufficient rigidity, so the emphasis (
1), (2), (3), (4) and (1)', (2)
Since the relative positional relationship between the plane formed by ', (3)', and (4)' and the displacement electric transducer attachment points 3 and 6 does not change, the displacement electric The displacement inputs to the transducers 3, 6 are determined. That is, in the configuration of this example, the transducer input displacement is equal to the arithmetic mean of each coil spring displacement.

…（２） となってさきの（１）式と同様台バカリを作ることがで
きる。...(2) As in the previous equation (1), we can create a stand back.

以上の実施例では４つの重点における変位を、それぞれ
求めて加算する方法と、機構的に集合し加算平均して１
個の変位電気変換器入力とする２通りの場合を述べたが
、本発明による方法につきより詳細に考えてみる。式中
の各記号は下記のととりである。In the above embodiments, the displacements at the four points are determined and added together, and the displacements are mechanically aggregated and averaged.
Having described two cases with displacement electrical transducer inputs, let us now consider the method according to the invention in more detail. Each symbol in the formula has the following meaning.

ｎ：ばねの取付総数 ■：載せ台上の載荷点の位置ベクトル、　　■（ｘ、ｙ
） ■：載せ台の傾きが零となる載荷点の位置　　ベクトル
、■（ｘ０、ｙ０） △■：■−■、△■（△ｘ、△ｙ） ■：載せ台を支持するｎ個のばねのうちｉ　　番目のば
ねの取付位置、■（ｘｉ、ｙｉ）ｋｉ：ｉ番目のばねの
ばね定数 ｋ０： ｚｉ：載荷時■点の変位（ばねの伸縮量）ｚ０：■点に
載荷したときの載せ台の変位△ｚｉ：ｚｉ−ｚ０ θ：載せ台の傾斜角 …（３） …（４） まづ計量物を載せたとき、載せ台が傾斜することなく一
様にｚ０だけ沈下変位するためには、■＝■より、Ｗｉ
＝ｚ０ｋｉを（３）、（４）式に代入整理すると…（４
）′ …（５） またｋｉがすべて等しいときには（ｋｉ＝ｋ０）…（５
）′ つぎに計量物が■から△■隔たった位置に載せられたと
きは、△■＝■−■であるから（４）式より より …（４）′′ Ｗｉ＝ｋｉｚｉ、ｚｉ＝ｚ０＋△ｚｉを（４）′′に代
入整理し、（５）式を使って、 △ｚｉは各々ばねｋｉが載せ台（平面）に拘束されてい
るので、傾斜角をθとして△ｚｉ＝θ（■−■）と代入
整理してθを求めると …（６） さきと同様ｋｉ＝ｋ０のとき …（６）′ ■は変位電気変換器の最適取付位置であり、載せ台上の
任意の点に載荷しても、■における変位は常にｚ０であ
るから、この変位を電気信号に変換すれば、偏置による
計量誤差を生じない。n: Total number of springs installed■: Position vector of the loading point on the platform, ■(x, y
) ■: Position vector of the loading point where the tilt of the platform is zero, ■ (x0, y0) △■: ■−■, △■ (△x, △y) ■: n springs that support the platform The installation position of the i-th spring, ■(xi, yi) ki: Spring constant of the i-th spring k0: zi: Displacement at point ■ when loaded (amount of expansion and contraction of the spring) z0: When loaded at point ■ Displacement of the platform △zi: zi - z0 θ: Inclination angle of the platform...(3) ...(4) First, when an object to be weighed is placed on the platform, the platform uniformly sinks by z0 without tilting. From ■=■, Wi
Substituting =z0ki into equations (3) and (4)...(4
)'...(5) Also, when all ki are equal, (ki=k0)...(5
)' Next, when the object to be weighed is placed at a position △■ away from ■, △■ = ■ - ■, so from equation (4)... (4)'' Wi = kizi, zi = z0 + △ Substituting zi into (4)'' and rearranging it, using equation (5), △zi has each spring ki restrained to the platform (plane), so assuming the inclination angle θ, △zi=θ(■ −■) and find θ...(6) As before, when ki=k0...(6)' ■ is the optimal mounting position of the displacement electric converter, and it can be placed at any point on the platform. Even when loaded, the displacement at ■ is always z0, so if this displacement is converted into an electrical signal, measurement errors due to eccentricity will not occur.

載せ台の傾斜については傾斜角をθで表わし、ばね定数
がそれぞれ異なる場合と等しい場合とを、示すと、θ、
ｚ０はそれぞれ（５）、（６）式および（５）′、（６
）′式のようになる。Regarding the inclination of the platform, the inclination angle is expressed as θ, and the cases where the spring constants are different and the same are shown as θ,
z0 is expressed by equations (5) and (6), and (5)' and (6), respectively.
)′ expression.

偏荷重により載せ台が変位する様子は第５図および第６
図に示すとおりである。第５図は計量物を載せてない状
態で載せ台は水平に保たれている。Figures 5 and 6 show how the platform is displaced due to unbalanced loads.
As shown in the figure. In Figure 5, the platform is kept horizontal with no object to be weighed.

第６図は載荷時であるが、載荷点が■であれば載せ台は
水平のまま一様に沈下変位するが、■から離れた位置に
載荷すると、偏荷重による力のモーメントを平衡させる
ために載せ台は傾く。つまり載せ台の変位は単純力によ
る一様な変位成分と、載荷点の偏りによる傾斜とを重ね
合わせたものとなる。載せ台の傾斜は見掛けの重力加速
度が変化するが直接計量値に誤差を生ずることはないし
、かりに傾斜誤差が１／３０００としても傾斜角は約１
．４８度（２５．８ミリラジアン）であり、載せ台の一
辺が１００ｍｍとしても前後左右の変位の差は２．６ｍ
ｍ程度が許容されるのに対し、載せ台の変位は１ｍｍ以
下であるから無視してよい。載荷による載せ台の姿勢変
化を単純にモデル化すると第７図のようになり、（５）
、（５）′式を満足する■（ｘ０、ｙ０）は変位電気変
換器を設置すれば、載せ台の如何なる位置に計量物を載
せても載荷による変位電気変換器への変位入力はｚ０と
なって荷重にのみ対応し偏りには無関係となる。（４）
、（４）′式より（４）式左辺はＷ■＝Ｗ（■＋△■）
と表わすことができ右辺第一項による変位ｚ０は第７図
のばね２５が支持して変位電気変換への入力となり、第
２項は第７図のヒンジ２５‐１により傾斜角θで平衡す
ると考えることができる。Figure 6 shows the state of loading. If the loading point is ■, the platform will remain horizontal and will sink uniformly, but if the loading point is placed away from ■, the moment of force due to the unbalanced load will be balanced. The loading table tilts. In other words, the displacement of the platform is a combination of a uniform displacement component due to a simple force and an inclination due to a bias in the loading point. Although the tilt of the platform changes the apparent gravitational acceleration, it does not directly cause an error in the measured value, and even if the tilt error is 1/3000, the tilt angle is approximately 1
．． 48 degrees (25.8 milliradians), and even if one side of the platform is 100 mm, the difference in displacement from front to back and left to right is 2.6 m.
m is allowed, whereas the displacement of the platform is less than 1 mm and can be ignored. If we simply model the change in the posture of the platform due to loading, it will look like Figure 7, (5)
, (5)' satisfies Equation (x0, y0) If a displacement electric converter is installed, the displacement input to the displacement electric converter due to loading will be z0 no matter where the weighing object is placed on the platform. Therefore, it corresponds only to the load and has nothing to do with bias. (4)
, From equation (4)', the left side of equation (4) is W■=W(■+△■)
The displacement z0 due to the first term on the right side is supported by the spring 25 in Fig. 7 and becomes an input to the displacement electrical conversion, and the second term is balanced at the inclination angle θ by the hinge 25-1 in Fig. 7. I can think about it.

一般的にばねｋ１、ｋ２、ｋ３、…、ｋｎはばね定数に
少しづつ個別差があり、また取付位置■１、■２、■３
、…、■ｎも製作上取付誤差を生じる。このための偏置
誤差は変換器の取付位置を■（ｘ０、ｙ０）の近辺でｘ
軸方向、ｙ軸方向にわずかにずらせて調整することによ
り取り除くことができる。Generally, springs k1, k2, k3, ..., kn have individual differences in spring constant, and the mounting positions ■1, ■2, ■3
,..., ■n also causes installation errors due to manufacturing. The eccentricity error for this is the mounting position of the converter in the vicinity of (x0, y0) x
It can be removed by adjusting it by slightly shifting it in the axial and y-axis directions.

以上の説明から明らかなように、本発明によれば次のよ
うな効果がえられる。As is clear from the above description, the following effects can be obtained according to the present invention.

（１）電気式台バカリのてこ等による荷重の支持、伝達
機構を省略単純化できる。(1) It is possible to simplify the load support and transmission mechanism by levers, etc. of the electric platform backer.

（２）任意の形状の載せ台をもつ電気式台バカリをつく
ることができる。(2) It is possible to create an electric stand base with a stand of any shape.

（３）非常に薄い形状の電気式台バカリを実現できる。(3) It is possible to realize a very thin electric base cover.

（４）載せ台の如何なる位置に載荷しても偏置誤差を生
じない。(4) An eccentricity error will not occur no matter where the load is placed on the platform.

（５）偏置誤差を取り除くための調整が容易である。(5) Adjustment to remove eccentricity errors is easy.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来の小型台バカリのてこ組みの一例を示して
いる。第２図は本発明による電気式台バカリ機構の簡単
な斜視分解図、第３図は正面（側面）断面略図である。 第４図は本発明を原理的に説明するための図で、ばねの
取付位置■、最適変換器取付位置■、載せ台をＳとして
水平面をｘｙ座標上にとって表わしている。第５図は本
発明による無載荷時の側面の概念図、同じく第６図は載
荷時を示す。第７図は第５図、第６図を単純にモデル化
した図である。 １…載せ台 ２…上部支持機構の腕 ３…変位電気変換器の上部 ４…ばね取付上部ねじ ５…計量コイルばね ６…下部支持機構の腕 ７…変位電気変換器の下部 ８…ばね取付下部ねじ ９…基底板 １１…さお（Ａ１重点、Ｆ１支点、Ｂ１力点）１２…長
機（Ａｉ、Ａｃ、Ｆ２、Ｂ２は１１に準ずる）１３…短
機（Ａ３、Ｂ３、Ｆ３は１１に準ずる）１４…載せ台 １５、１６…連結棒 ２５…計量ばね ２５‐１…ヒン■FIG. 1 shows an example of a lever assembly of a conventional small-sized stand backer. FIG. 2 is a simple perspective exploded view of the electric platform backing mechanism according to the present invention, and FIG. 3 is a schematic front (side) sectional view. FIG. 4 is a diagram for explaining the principle of the present invention, and shows the spring mounting position (2), the optimum transducer mounting position (2), the platform S, and the horizontal plane on the xy coordinates. FIG. 5 is a conceptual diagram of the side view when no load is applied according to the present invention, and FIG. 6 is a side view when the present invention is loaded. FIG. 7 is a simple model of FIGS. 5 and 6. 1... Mounting platform 2... Arm of upper support mechanism 3... Upper part of displacement electrical converter 4... Upper spring mounting screw 5... Metering coil spring 6... Arm of lower support mechanism 7... Lower part of displacement electrical converter 8... Lower part of spring mounting Screw 9... Base plate 11... Rod (A1 point, F1 fulcrum, B1 force point) 12... Long machine (Ai, Ac, F2, B2 are in accordance with 11) 13... Short machine (A3, B3, F3 are in accordance with 11) )14...Place 15, 16...Connecting rod 25...Measuring spring 25-1...Hin■

Claims (1)

【特許請求の範囲】 電気式台バカリにおける変位電気変換器の最適な配置法
に関連して、 ３個以上任意個の直線性の良好なばねにより剛体平板を
水平に支持し、 前記平板上に計量物を載せたとき、変位電気変換器の入
力となる載荷時の重直方向の変位が載荷点の位置に係ら
ず、重量にのみ比例して偏載誤差を生じない前記平板上
の位置を、 前記ばねの取付位置とばね定数とにより、変位電気変換
器の最適取付位置として決定することを特徴とする電気
式台バカリの重量検出装置。[Claims] In relation to the optimal arrangement method of displacement electric transducers in an electric platform backer, a rigid flat plate is supported horizontally by three or more arbitrary springs with good linearity, and a rigid flat plate is supported horizontally on the flat plate. When an object to be weighed is placed on it, the displacement in the vertical direction during loading, which is the input to the displacement electric converter, is proportional to the weight, regardless of the position of the loading point, and the position on the flat plate is such that no unbalanced loading error occurs. . A weight detecting device for an electric platform backer, characterized in that the optimum mounting position of the displacement electric converter is determined based on the mounting position of the spring and the spring constant.