JPS623697Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electronic scale that measures a load by converting it into an electrical signal.

Conventionally, there are electronic platform scales that measure weight by the movement of a lever that receives the load from a tray on which the object to be measured is placed. uses a V-shaped blade and a blade holder. Machining these blades and blade holders requires high precision, and since the blades have sharp tips, it is difficult to temper their hardness, making them extremely difficult to manufacture.

This invention was made in view of these points, and the purpose is to provide an electronic scale that is easy to manufacture and can perform precise measurements.

In this invention, a saucer frame is provided by connecting the inner ends of a plurality of radially arranged flexible arms to each other by a flexible part, and the outer ends of the flexible arms are supported on a base via a leaf spring. The flexible arm is provided with a pressure-receiving part that supports the saucer, and therefore the load of the saucer is transmitted to the pressure-receiving part, and the unbalanced load is corrected to a vertical load by the deformation action of the saucer frame, which is then transmitted from one load transmission part to the transducer. In particular, by changing the attachment position of the leaf spring to the base,
For each flexible arm, the position of the pressure receiving part that bisects the entire length from the load transmitting part to the attachment part of the leaf spring can be easily finely adjusted to a position where an equal leverage ratio can be obtained. The structure is such that a tray frame that exhibits an important load transfer function can be easily manufactured.

An embodiment of this invention will be described based on the drawings. Reference numeral 1 denotes a base formed by a manufacturing method such as sheet metal processing or aluminum alloy casting, and a thin electric resistance type load cell 2, which is a transducer, is fixed to the bottom of this base 1. Then,
A saucer frame 4 that supports the saucer 3 is provided. This saucer frame 4 has a plurality of flexible arms 5,
6, 7, and 8 are arranged radially and are integrally pressed by a stainless steel plate. That is, flexible portions 9 that elastically bend in the vertical direction are formed at the inner ends of the flexible arms 5, 6, 7, and 8 and are connected to each other, and ribs 10 are bent on both sides of the intermediate portions, and the outer ends are bent. A plate spring 11 made of steel plate or phosphor bronze is installed at one end.
are fixed by means such as spot welding.
The lower ends of these leaf springs 11 are connected to the saucer frame 4.
A load transmission rod 12 which is a load transmission section provided at the center of
The spacer 14 is formed in a substantially “2” shape extending in the radial direction with the center at the center.
is fixed. Then, by screwing the screw 16 inserted into the elongated hole 15 formed in the extending portion 13 and the spacer 14 into the base 1, the leaf spring 11 is centered on the load transmission rod 12 with respect to the base 1. It is attached so that it can slide freely in the radial direction and can be fixed at any position.

Further, the flexible arms 5, 6, 7, and 8 are formed with hemispherical recesses 17 that serve as pressure receiving portions. In addition, the ring 1 facing these recesses 17
8 is fixed to the inner surface of the saucer 3. A steel ball 19 having a diameter smaller than the radius of the spherical surface of the recess 17 and the radius of the ring 18 is held by the ring 18 as a pressurizing part of the saucer 3. In addition, the saucer 3
is urged upward by a spring 20, but the amount of upward movement is limited by the head 22 of the bolt 21. That is, the bolts 21 are screwed into the base 1 through holes 23 formed in the saucer 3, and the interference portions 24 facing each other below the heads 22 of these bolts 21 are formed by a separate member and fixed to the lower surface of the saucer 3. has been done. Of course, the interference portion 24 may be formed integrally with the saucer 3. The distance between this interference portion 24 and the head 22 of the bolt 21 is set to a dimension A when the saucer 3 is pushed downward, as shown in FIG. This dimension A is set to a value smaller than the depth B of the recess 17 and the thickness C of the ring 18 shown in FIG. Note that the saucer 3
is a display mounted on the base 1 (not shown).
A display window 25 corresponding to the above is formed.

In such a configuration, when an object to be measured is placed on the tray 3, the tray frame 4 deforms downward and transmits the load from the load transmission rod 12 to the load cell 2, and the load cell 2 responds to the magnitude of the transmitted load. It deforms and emits electrical signals. That is, each flexible arm 5, 6, 7, 8 distributes the load of the object to be measured according to the position of the object on the saucer 3 and supports the support plate spring 1.
1 and the flexible portion 9 are deflected downward, and the load transmission rod 12 combines the loads distributed and received by the flexible arms 5, 6, 7, and 8 and transmits the combined loads to the load cell 2. At this time, the steel ball 19 vertically transmits the load to the recess 17 having a larger radius. Also, leaf spring 1
1 is slidable on the base 1 and can be fixed at any position, so the ratio of the distance a from the attachment part of the leaf spring 11 to the base 1 to the recess 17 and the distance b from the recess 17 to the load transmission rod 12 ( The adjustment work to set the lever ratios equally can be easily performed. Therefore, each flexible arm 5, 6, 7, 8 deforms in proportion to the load received in a distributed manner and accurately transmits the load to the load transfer rod 7.

To explain this effect using a diagram, W = W ₁ + W ₂ + W ₃ + W ₄ ...... (1) As shown in equation (1), the load W applied to the saucer 3 is reduced by W ₁ due to each recess 17. , W ₂ , W ₃ , and W ₄ . Input load to these recesses 17
W ₁ , W ₂ , W ₃ , W ₄ are flexible arms 5,
By the deformation operations 6, 7, and 8, W ₀₁ , W ₀₂ , W ₀₃ ,
The output load is corrected to W ₀₄ and transmitted to the load transmission rod 12 . That is, if the resultant force of the output load transmitted from the load transmission rod 12 to the load cell 2 is W ₀ , then the following equation is derived: W ₀ =W ₀₁ +W ₀₂ +W ₀₃ +W ₀₄ (2). Also, as shown in Figure 8,
When an input load is applied to each concave portion 17, the inner ends of each flexible arm 5, 6, 7, and 8 are deflected by an amount of deflection δ, and the deflection forces generated as reaction forces at this time are F ₁ and F ₂ , respectively. , F ₃ , F ₄ , the distance from the load transmission rod 12 to the recess 17 is b, and the distance from the recess 17 to the attachment point of the leaf spring 11 to the base 1 is a, then W ₀₁ =a/a+bW ₁ −F ₁ ………(3) W ₀₂ =a/a+bW ₂ −F ₂ ………(4) W ₀₃ =a/a+bW ₃ −F ₃ ………(5) W ₀₄ =a/a+bW ₄ − The formula F ₄ ......(6) is derived. Therefore, W ₀ =a/a+b(W ₁ +W ₂ +W ₃ +W ₄ )−(F ₁ +F ₂ +F ₃ +F ₄ )……(7) W=a/a+bW−F(W)…… (8) The following formula holds true.

FIG. 9 shows the relationship between the deflection amount δ of the tray frame 4 and the load W applied to the tray ₃ , as determined by an experiment.
The amount of deflection δ at the center of the tray frame 4 when W ₂ , W ₃ , and W ₄ are applied to each recess 17 is measured with a dial gauge and plotted with circles.
Also, assuming that the object to be measured is placed in the corner of the tray 3, the full load is applied to a specific recess 17. In other words, the deflection δ when _W1 = W, _W2 = _W3 = _W4 = 0 is plotted with x marks. Therefore, the deflection δ of the load cell 2 is also small at a maximum of 0.5 mm, and within this range, W and δ are proportional to the theoretical value regardless of where the object to be measured is placed on the tray 3.
This proves that extremely accurate measurements can be performed. The load cell 2 is thin and the height of the receiving pan frame 4 is also extremely low, so the overall shape is flat and compact, making it easy to carry as a lightweight range scale for weighing mail and the like. The important part for load transmission is the receiving pan frame 4.
It can be produced very easily by pressing.

Furthermore, since the lower end of each leaf spring 11 has an extending portion 13 extending in the radial direction, a work space is formed above the screw 16 when tightening and fixing with the screw 16, making assembly work easier. I can do it. Of course, as shown in Fig. 10, the U-shaped leaf spring 2
6 may also be used. In this case, it is preferable to insert the screw 16 from below and fix the leaf spring 26 with the screw 16 and nut 27. Further, the spacer 14 is not essential, and a washer may be substituted or omitted.

Note that the saucer frame 4 has four flexible arms 5,
However, the number of flexible arms is not limited to four, and may be set to three, five, six, etc., for example. In addition, the flexible arm 5,
The lengths of 6, 7, and 8 may be different from each other as long as the lever ratio at which they are divided into two by the recess 17 is equal. Furthermore, a plurality of single flexible arms or a plurality of pairs of flexible arms may be formed and these may be combined to form the saucer frame.

Since this device is constructed as described above, the load of the receiving tray can be transmitted to the pressure receiving section, and the unbalanced load can be corrected to a vertical load by the deformation action of the receiving tray frame, and can be transmitted from the load transmitting section at one point to the transducer. In addition, by adjusting the attachment position of the leaf spring to the base, the position of the pressure receiving part that bisects the length from the leaf spring to the load transmission part of each flexible arm can be easily adjusted to a position where an equal leverage ratio can be obtained. This allows accurate weight measurement, and has the advantage that it is also possible to easily manufacture a saucer frame that performs the main function of load transmission.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is a perspective view, Figure 2 is a plan view with the saucer removed, Figure 3 is a longitudinal side view taken along the - line in Figure 2 including the saucer, and Figure 4 is a perspective view of the saucer frame. , Figure 5 is a partially enlarged longitudinal side view showing the load transmission structure between the saucer and saucer frame, Figure 6 is a partially enlarged vertical side view showing the stopper structure of the saucer, and Figure 7 is the saucer frame. An action explanatory diagram three-dimensionally showing the load transfer action to the 8th
The figure is an explanatory diagram showing the load transmission effect to the saucer frame from the side, Figure 9 is a graph showing the relationship between the amount of deflection of the load cell and the load, and Figure 10 is a partial longitudinal section showing a modification of the leaf spring. FIG. 1...Base, 2...Load cell (transducer), 3...Saucer, 4...Saucer frame, 5
~8... Flexible arm, 9... Flexible part, 11... Leaf spring, 12... Load transmission rod (load transmission part), 17
... recess (pressure receiving part), 26 ... plate spring.

Claims (1)

[Claims for Utility Model Registration] 1. A transducer that converts and detects a load into an electrical signal is provided on the base, and the inner ends of a plurality of radially arranged flexible arms are elastically deformed in the vertical direction. A saucer frame connected via a flexible portion is provided, a load transmitting portion for transmitting a vertical load to the transducer is provided at the center of the saucer frame, and a pressure receiving portion for receiving the load of the saucer is provided at an intermediate portion of the flexible arm. A leaf spring integrally formed or a leaf spring formed as a separate member is provided at the outer end of the flexible arm, and these leaf springs are slidable in a radial direction centering on the load transmission part and at any position. An electronic scale characterized in that it is fixedly connected to the base. 2. Utility model registration claim No. 1, characterized in that the shape of the leaf springs is set such that the lower ends thereof extend in a radial direction centered on the load transmitting part, and the lower ends of the leaf springs are connected to the base. The electronic scale described in item 1.