JP2001066178A - Electronic force balance having double lever - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic force balance capable of taking a leverage largely, and capable of being miniaturized as a whole. SOLUTION: A first beam 8 is connected to a load receiving part 2 of an integrated Roberval mechanism 1, and the rear end 8b of the first beam 8 is connected to the rear end part 12b of a second beam 12 through a first suspension band 11. The second beam 12 is composed so as to be swung with a fulcrum member 13 as a fulcrum, and the head part of the second beam 12 is connected to an electromagnetic part 14, and a double lever having a high leverage is formed by the first and the second beams 8, 12, and the electromagnetic part 14 is arranged adjacent to the load receiving part 2 to thereby form the whole electronic force balance compactly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic balance, and more particularly, to an electromagnetic balance type electronic balance capable of realizing a high leverage ratio with a small size.

[0002]

2. Description of the Related Art Electromagnetic balance type electronic balance (hereinafter referred to as "electronic balance")
), There is a so-called analytical balance capable of measuring an extremely small amount of about 1 μg, but recently, the weighing is several kg.
From general-purpose products to large devices of several hundred kg.

FIG. 6 shows a structure of a load transmitting mechanism of an electronic balance having a barbal mechanism separately proposed by the inventor.
Since this roberval mechanism is formed from one metal block, the roberval mechanism formed from such a single metal block is hereinafter referred to as an "integrated roberval mechanism" including the present invention.

The integral type roberval mechanism section 51 is fixed to a mechanism section support member 53 so as to be supported in a cantilever manner, and is formed with thin portions 51a to 51d at four upper and lower portions to form a roberval portion. Have been. A load transmitting beam 57 is provided so as to have a fulcrum 59 at a fulcrum mounting portion 55 protruding from the roberval portion, and one end of the beam 57 is connected to a load receiving portion 51B of the roberval mechanism by a suspension band 61. The end is connected to the electromagnetic unit 58.

In other words, the load transmitting beam 57 is
A / b based on the distance a between the support band 59 and the connection point between the fulcrum 59 and the electromagnetic unit 58 is set as a leverage ratio, and the load WA of the weighed object is determined by the load transmitting beam. 57 and the electromagnetic ratio 5 with the leverage ratio a / b.
8.

[0006]

The load transmitting beam in the above configuration has a leverage ratio a / b of about 1 / several hundreds, and is particularly effective for an electronic balance having a relatively small weighing capacity. is there. However, when the weight of the electronic balance is set to be large, the following problem occurs in this configuration, and some countermeasure is required.

First, as a measure to cope with a large weighing, a method to cope with a large weighing by increasing the electromagnetic force of the electromagnetic section and a method to set a large lever ratio of the load transmitting beam can be considered. The method of increasing the electromagnetic force of the unit is not realistic because it causes an increase in the size and weight of the electromagnetic unit and is affected by heat generation due to an increase in power applied to the electromagnetic unit and formation of a strong magnetic field. Therefore, this can be coped with by setting the lever ratio of the load transmitting beam large. To cope with such a large lever ratio, for example, when the electromagnetic force in the electromagnetic unit is 30 g and the weighing of the electronic balance is 60 kg (60,000 g), the lever ratio a / b is 1/2000 or You need to set more.

In order to realize the above leverage ratio, in the configuration of FIG. 6, there is a limit to the reduction of the distance a due to its configuration.
Needs to be set large, that is, the entire length of the load transmitting beam 57 needs to be set long, and the entire load transmitting mechanism becomes large. In other words, in the illustrated configuration, the load portion of the load WA and the electromagnetic portion 58 are located at both ends via the load transmitting beam 57. Therefore, when the load transmitting beam 57 is set to be long, the weighing pan P is included. And the whole electronic balance becomes quite large.

[0009]

SUMMARY OF THE INVENTION The present invention is an electronic balance constructed in view of the above-mentioned problems, and comprises two load transmitting beams constituting a double lever, and a fulcrum supporting the two load transmitting beams. And an integrated roberval mechanism configured to guide the operation of each of the load transmitting beams, and a portion of the integrated roberval mechanism that receives the load of the weighing object and the electromagnetic unit are adjacent to each other. The double lever is, for example, with respect to the integrated roberval mechanism,
One end supports the primary fulcrum, and the other end is configured by providing an extended portion adapted to support the secondary fulcrum, thereby realizing a high leverage ratio and installing a weighing dish. An electronic balance characterized in that the entire electronic balance is configured to be formed smaller than the weighed amount.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In an integrally formed roberval mechanism, an electromagnetic section is arranged adjacent to a load receiving section that receives a load of a weighed object. The load receiving portion of the roberval mechanism and one end of the first load transmitting beam are connected by a connecting member called a suspension band, and a fulcrum member made of a leaf spring or the like is provided at a position close to the suspension band. The first load transmitting beam is interposed between the first load transmitting beam and the roberval mechanism, whereby the first load transmitting beam swings around the fulcrum member.

The other end of the first load transmitting beam is connected to the second
Is connected to the second load transmitting beam via the suspension band. A second fulcrum member is interposed between the end of the second load transmitting beam and the roberval mechanism, whereby the second fulcrum member is arranged close to the second suspension band. , The second load transmitting beam is the second load transmitting beam.
Is configured to swing about the fulcrum member.

The other end of the second load transmitting beam is connected to an electromagnetic unit, whereby the load of the weighed object is first transmitted to the first load transmitting beam, and the load of the first load transmitting beam is transmitted to the first load transmitting beam. The load is transmitted to the second load transmitting beam in accordance with the lever ratio, and the transmitted load is further transmitted to the electromagnetic unit in accordance with the lever ratio of the second load transmitting beam. Is transmitted.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. 1 to 4 show an embodiment of the present invention.
FIG. 3 is a diagram showing a simplified function of the present invention. First, an arrow 1 in the drawing indicates a roberval mechanism formed integrally. 2
Is a load receiving portion of the Roberval mechanism that receives the load of the weighed object, and an end facing the load receiving portion 2 is a fixed portion 3, and a supporting portion 4 A connected to the base 4. As a result, the fixed portion 3 is fixed, so that the entire integrated roberval mechanism 1 is supported by the support portion 2A in a cantilever manner. Reference numerals 6a, 6b, 6c, and 6d denote thin portions of the integrated roberval mechanism 1. By forming these thin portions, the integrated roberval mechanism 1 operates as a roberval.

Next, reference numeral 5 denotes the above-mentioned integrated roberval mechanism 1.
, One end of which is extended toward the space 7 constituting the Roberval, and the other end is a pair of support beams 5a,
Reference numeral 5b denotes a position protruding behind the support 4A on the base 4 side.

Reference numeral 8 denotes a first load transmitting beam (hereinafter, referred to as a "first beam") which forms one of the members constituting the double lever. One end of the first beam is located in the space 7 of the integrated Roberval mechanism 1, and the first beam and the beam 5
A fulcrum member 9 made of a leaf spring or the like is interposed between the two (see FIG. 3). Further, one end of a first suspension band 10 is attached to the distal end portion 8a of the first beam 8,
The other end of the suspension band 10 is connected to the load receiver 2 of the integrated roberval mechanism 1, and the displacement of the load receiver 2 due to the weighing object is transmitted to the first beam 8.

The rear end 8b of the first beam 8 is positioned so as to bend at a right angle from the central portion 8c located along the beam 5, and the rear end of the rear end 8b has a second suspension band. 1
One end is attached. Next, reference numeral 12 denotes a second load transmitting beam (hereinafter, referred to as a “second beam”), which is arranged in parallel with the first beam 8 via the beam portion 5. That is, of the rear end portion 12b positioned so as to be bent at a right angle to the central portion 12c similarly to the rear end portion 8b of the first beam, the second suspension band 11 Are connected to each other.

The second suspension band 1 of the rear end 12b
Supporting members 13, 13 such as leaf springs are fixed to the rear end edge of the position opposite to the side edge to which the connecting member 1 is connected. The second beam 12 is fixed to the rear end edges of 5a and 5b, and is configured to swing around a fulcrum member 13 located at the rear end of the second beam. The distal end portion 12a of the second beam 12 is bent at a predetermined angle with respect to the central portion 12c, and is connected to an electromagnetic portion 14 disposed adjacent to the load receiving portion 2 of the integrated roberval mechanism 1.

FIG. 5 is a view conceptually showing a double lever structure using the first beam 8 and the second beam 12 described above. In the figure, the lever ratio of the first beam 8 is a / b,
Although the lever ratio of the beam 12 is c / d, it is easy to realize a lever ratio of about 1 / several hundreds in each beam. Therefore, the lever ratio a / b × c of the double lever is used. It is easily feasible to make the leverage ratio 1 / several thousands in / d. Further, in the present configuration, the first beam 8 and the second beam 12 are arranged as shown in the drawing, so that the load receiving portion 2 of the integrated roberval mechanism 1 and the electromagnetic portion 14 are adjacent to each other. For this reason, the weighing dish P is arranged so as to be located substantially at the center of the weighing mechanism.

[0019]

According to the present invention, the load receiving portion for receiving the load of the weighing object and the electromagnetic portion are arranged adjacent to each other, so that the load receiving portion is located at the center of the mechanism constituting the electronic balance. Since the positions are close to each other, a high leverage ratio can be realized, and the entire electronic balance including the weighing dish can be configured to be compact.

[Brief description of the drawings]

FIG. 1 is a perspective view of a load transmitting mechanism of an electronic balance showing one embodiment of the present invention.

FIG. 2 is a plan view of the load transmitting mechanism shown in FIG.

FIG. 3 is a sectional view of the load transmitting mechanism shown in FIGS. 1 and 2;

FIG. 4 is a view as viewed in a direction A in FIG. 1;

FIG. 5 is a conceptual diagram of a mechanism according to the present invention.

FIG. 6 is a side view of a load transmission mechanism separately proposed by the inventor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Integrated roberval mechanism 2 Load receiving part 3 Fixed part 4A Support part 5 Beam part 5a, 5b Support beam 6a, 6b, 6c, 6d (at the rear end of beam part) Thin part 7 Space part 8 First load transmitting beam 8a 1st load transmitting beam front end 8b 1st load transmitting beam rear end 8c 1st load transmitting beam center 9 fulcrum member 10 first suspension band 11 second suspension band 12 second load transmission Beam 12a second load transmitting beam tip 12b second load transmitting beam rear end 12c second load transmitting beam center 13 fulcrum member 14 electromagnetic unit

Claims (3)

[Claims] 1. An electronic balance configured to transmit a load of a weighed object to an electromagnetic unit via a load transmitting beam, wherein the electromagnetic unit is disposed in proximity to a load receiving unit that receives the load of the weighed object. A first load transmitting beam connected to the load receiving portion with a leverage ratio, and a second load transmitting beam connected to the first load transmitting beam with a predetermined leverage ratio; The load of the weighing object applied to the load receiving portion is transmitted to the electromagnetic portion located close to the load receiving portion via the first and second load transmitting beams. Electronic balance having. 2. The first and second load transmitting beams are both supported by an integrated roberval mechanism, which is opposed to the load receiving section via a load receiving section and a roberval operating section. A first fixed part, a first part and a second part, which are extended from the fixed part toward the load receiving part and the other end is configured to protrude toward a member supporting the integrated roberval mechanism. The second load transmitting beam is vertically arranged in parallel through this beam portion, and one end of the first load transmitting beam is connected to the load receiving portion via a fulcrum supported by the beam portion, And the other end is connected to a second load transmitting beam, the second load transmitting beam is supported by the integrated roberval mechanism via a fulcrum provided at a rear end of the beam portion, and Is the load receiving part of the integrated Roberval mechanism. 2. The electronic balance having a double lever according to claim 1, wherein the electronic balance is configured to be connected to an electromagnetic unit located in the vicinity. 3. The first and second load transmitting beams are configured to have one central portion, and a front end portion and a rear end portion bent and located with respect to the central portion. 3. The electronic balance with double levers according to claim 1, wherein a central portion of the beam is located along either side of the beam portion of the integrated Roberval mechanism.