JPS60115814A - Mass gauge - Google Patents

Abstract

PURPOSE:To measure mass easily and accurately by providing a device which adds and reduces a weight. CONSTITUTION:The output of a processing part 24 is the value w1 obtained by multiplying the current mass m1 by gravitational acceleration during the metering of an optional product with the mass m1, and stored in a memory 26. In this state, when a weight of mass (m) is loaded on a subordinate elastic body by a weight loading and unloading device 22, the tensile force of a force detector 9 decreases and the output of the processing part 24 is the value obtained by subtracting (w), i.e. product of mass (m) and gravitational acceleration (g) from w1 and stored in a memory 28. A subtraction part 30 calculates (w) by subtracting the stored value of the memory 28 from the stored value of the memory 26 and stores it in a memory 32. Then, the output w2 of the processing part 24 when a product whose mass mx is unknown is measured with the weight removed is divided by (w) to obtain the mass mx without the influence of the gravitational acceleration (g).

Description

[Detailed description of the invention] The present invention relates to a mass meter.

Previously, the inventor of the present invention proposed a force measuring device as shown in FIGS. 1 to 3. In Figure 1, l is a donkey.
It is a Pal-type main elastic body, one end 2 of which is attached to a fixed part 3, and the other end 4 of which is attached a platform 5 for applying a load. A secondary elastic body 6 is arranged above the main elastic body 1. One end 7 thereof is formed integrally with one end 2 of the main elastic body 1. A string 9 is stretched between the other end 8 of the auxiliary elastic body 6 and the other end 4 of the main elastic body 1 as a force detector. When an article is placed on the platform 5, tension is generated in the string 9 in proportion to the weight of the article. Therefore, by detecting this tension, the weight can be determined. Therefore, as shown in FIG.
0, and both ends of 'jp9 are connected to an oscillator 11 forming a part of the processing section. When a slight deflection occurs in the string 9 due to tension, a current flows through the string 9 according to Fleming's right-hand rule.The current is amplified by the amplifier 12 in the oscillator 11, and the amplified current passes through the feedback resistor 13. The current fed to the string 9 through the string 9 and deflected more and more according to Fleming's left-hand rule, the current fed to the amplifier 12 increases more and more. Eventually, the energy given by the amplifier 12 and the string 9
The string 9 is deflected to a position where the bending stress is balanced and returns in the opposite direction. As a result, a current flows in the string 9 in the opposite direction to the current direction, and this current is amplified by the amplifier 12.
It is supplied to the string 9, and the string 9 bends in the opposite direction. Thereafter, this process is repeated, and the string 9 vibrates at the frequency f.

This frequency f can be determined. However, n is the harmonic number of vibration, l is the effective length of the string 9, p is the tension of the string 9, g is the gravitational acceleration 7ffi, and r is the mass per unit length of the string 9. Therefore, as shown in FIG. 3, the counter 14 forming the remaining part of the processing section counts the frequency f of the oscillator 12, the calculation section 15 calculates the tension p, and further calculates the weight proportional to the tension p and displays it. Part 16
to be displayed. In addition, 17 is a gate, which is used to cause the opening counter 14 of the 7-4-'' cliff fin to count the frequency. This is only for setting constants for calculation in the calculation section 15.

Such a force measuring device only measures force, not mass.

Therefore, in order to measure mass using this, it is necessary to make corrections according to the gravitational acceleration of the area where it is used, but it is necessary to limit the area where it can be used.

For example, as disclosed in JP-A-52-149154, a weight with a known internal mass is loaded onto a load cell when the load cell is in an unloaded state, and the correction is made according to the gravitational acceleration of the place of use. There is a method that makes corrections based on the detected value at that time and the known mass, but the weight must have a mass close to the weight of the scale, and correction can only be made when there is no load. could not be done and was not practical.

An object of the present invention is to provide a mass meter configured by adding a simple correction device to the force measuring device described above.

Therefore, as shown in FIG. 4, the present invention includes the above-mentioned force measuring device 2o, a device 22 for adding and removing a weight to the auxiliary elastic body,
A first memory 2 that stores the output of the processing unit 24 in the force measuring device f20 when no weight is loaded on the secondary elastic body.
6, and the processing section 2 in a state where the weight is loaded on the auxiliary elastic body.
A second memory 28 that stores the output of 4, a subtraction unit 3o that calculates the difference between the first memory 26 and the second memory 28, and a subtraction unit 3o that stores the output of this subtraction unit 3o. 3 memory 32, and a division section 34 that divides the output of the processing section 24 with the article loaded on the main elastic body by the value stored in the third memory 32.

The mass meter configured in this manner operates as follows. now,
Assume that this mass meter weighs an article without loading a weight on the auxiliary elastic body, and that it is currently weighing an article having a mass m1. At this time, the output of the processing unit 24 is ml
The value W1 is obtained by multiplying the gravitational acceleration g by the gravitational acceleration g, and the first memory 26 stores this. In this state, when a weight with a mass m is loaded onto the secondary elastic body by the weight addition/removal device 22,
The tension of the force detector 9 decreases, and the output of the processing unit 24 becomes Wl-W, which is obtained by subtracting W obtained by multiplying the mass m by the gravitational acceleration g from wl, and this is stored in the second memory 28. The subtraction unit 30 subtracts the value wi-w stored in the second memory 28 from the value W stored in the first memory 26 to calculate W. W is stored in the third memory 32. Processing section 2 when an article with unknown mass mx is picked up with the weight removed.
Dividing the output W2 (mx - g) of 4 by W gives 1
2/W=mX-g/rn-g=mx/m, and the mass mx can be known without being affected by the gravitational acceleration g.

Alternatively, a weight may be loaded onto the auxiliary elastic body during measurement, and the weight may be removed from the auxiliary elastic body when making adjustments. As described above, according to the present invention, mass can be easily and accurately measured simply by adding or subtracting a weight.

Hereinafter, this invention will be explained in detail based on one embodiment shown in FIGS. 5 to 7. It should be noted that since the force measurement neck is the same as the conventional one, the same parts are given the same reference numerals and the explanation will be omitted. In FIG. 5, the weight adding/removing device 22 consists of a plate-shaped body 4 whose base end is connected to one end of the auxiliary elastic body 6 with a hinge 38.
A weight 42 is provided at the tip of the plate member 40, a cam 44 is brought into contact with the lower surface of the plate member 40, and the cam 44 is rotated by a motor 46 so that the convex portion of the cam 44 contacts the plate member 40. In the state where the weight 42 is not loaded on the other end 8 of the secondary elastic body 6, and in the state where the convex part of the cam 44 is not in contact with the plate-shaped body 40, the weight 42 is not loaded on the other end 8 of the secondary elastic body 6. A weight 42 is loaded thereon. Although not shown in the figures, the motor 46 is attached to the fixed part 3 by suitable fittings. The thermal cam 44 is arranged so that it does not come into contact with the secondary elastic body 6 no matter how it rotates. For example, the mass of the weight 42 is 1 kg when the force measuring device weighs 1 kg, and the mass of the main elastic body 1 is 900 kg.
If the secondary elastic body 6 receives a force of 100y, the secondary elastic body 6 should be selected to be capable of applying a force of approximately 1002y.

Processing unit 24 excluding oscillator 11, first to third memories 2
As shown in FIG.
It is realized by a microcomputer consisting of 2.

Further, this microcomputer displays the mass data obtained by the division section 34 on the display section 54, and also controls the mode 46 of the weight addition/subtraction device 22.

Next, the functions implemented by the microcomputer will be explained with reference to FIG. It is assumed that an appropriate article is placed on the platform 5 and the weight data WO has already been obtained from the frequency f of the oscillator 11. Further, it is assumed that suitable correction data has already been stored in the third memory and that the weight 42 has not been loaded. In the figure, the weight data WO is read in step 60, and it is determined in step 62 whether or not the weight 42 is loaded. Since there is no loading type at present, the process moves to step 64 and the weight data WO
is divided by the data in the third memory, and the divided value is displayed on the display section 54 as qualitative data. And step 66
The mass data is processed in step 68, and it is determined whether a certain period of time has elapsed or not, and if it has not elapsed, steps 60.62, 64, 66.6
Repeat steps 8 in order.

When a certain period of time has elapsed, the process moves to step 70, and the M amount data WO that has just been read is stored in the first memory.

Then, in step 72, the motor 46 is controlled and the weight 4!
i is loaded onto the secondary elastic body 6. Then, the process returns to step 60. At this time, the tension of the first string 9 is reduced to the same degree as when the article is removed from the platform 5. Therefore, the weight data WO also decreases considerably. Then, in step 62, it is determined again whether or not the weight 42 is loaded, but since it is loaded this time, the process moves to step 74, and the reduced weight data WO is stored in the second memory. The motor 46 is controlled to remove the weight 42 from the auxiliary elastic body 6.

Thereafter, in step 78, the pattern needle data WO is read, and in step 80, it is compared with the data in the first memory. If they are the same, it means that there was no change in the item on the platform 5'' while the weight 42 was being placed on and taken off.

1 [The change in tension caused by the weight can be seen in the pain. Therefore, in step 82, the difference between the values stored in the first memory and the second memory is calculated and stored in the third memory, and the process returns to step 60, and thereafter proceeds to steps 62, 64, and 66.

Further, in step 80, when the weight data WO read in step 78 is compared with the data in the first memory, if the two are not equal, it means that there was a change in the article on the platform 5 while the weight 42 was being placed and taken down. Therefore, the change in tension due to the weight cannot be read accurately, so step 6
Returns to 0 and moves to steps 62, 64, and 66.

The reason for repeating such correction at predetermined time intervals is to take into account the use in places with severe temperature changes or installation in cars or ships that tend to tilt. When the twisted weight 42 is loaded on the auxiliary elastic body 6, the tension on the string 9 is reduced to the same level as when no article is placed on the platform 5. In order to increase the tension, the initial tension must be four to six times the change in tension that occurs in the string 9 when the load changes the most, so the tension in one string 9 will not be close to zero and can be corrected. can. For the same reason, correction can be made even if the weight 42 is placed on and taken off from the platform 5 with no article placed on it.

In the above embodiment, the weight 42 was loaded on the secondary elastic body 6 when making the correction, but the weight 42 was always loaded on the secondary elastic body 6,
The weight 42 may be removed from the auxiliary elastic body 6 when making the correction. Although the cam 44 and the motor 46 are used to add/remove the weight 42, any structure that can add/remove the weight 42 may be used, for example, an electromagnetic solenoid may be used. Also,
A weight 42 is provided at the tip of the plate-shaped body 40, and the base end is attached to the hinge 3.
8 to the one end 7 of the secondary elastic body 6, the present invention is not limited to this, and any structure can be used as long as the force is accurately applied to the one end 8 of the secondary elastic body 6. Further, although the secondary elastic body 6 is placed above the main elastic body 1 to apply tension to the string 9, the secondary elastic body 6 may be placed below the main elastic body 1 to apply compressive force to the string 9.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional force measuring device, Fig. 2 is a circuit diagram of an oscillator used in the conventional force measuring device, Fig. 3 is an electric circuit diagram of the conventional force measuring device, and Fig. 4 is a diagram according to the present invention. FIG. 5 is a perspective view of an embodiment of the mass meter according to the present invention, FIG. 6 is a block diagram of the embodiment, and FIG. 7 is a flowchart of the embodiment. 20...force measuring device, 22...weight addition/removal device, 26
・・1st memory, 28・・2nd memo 'J, 30・
... Subtraction section, 32... Third memory, 34... Division section. Patent applicant Yamato Seiko Co., Ltd. Agent Satoshi Shimizu and two others21 Figure) 1. Indication of the case No. 19 Japanese Patent Application No. 58-225073 2. Title of the invention Mass meter 5 "Detailed description of the invention" column of the specification to be amended. 6 Contents of the amendment (]) "Memorized value W" on page 6, line 5 of the specification is corrected to "memory value WI J." (2) 1 multiplied by 1 on page 11, line 16 of the specification. ” is corrected as follows. You may write it down. In the above example, the tension P
Alternatively, any device that can sense force can be used, such as a crystal force detector or a tuning fork force detector. that's all

Claims (1)

[Claims] (1) A force detector stretched between the action part of the main elastic body and a sub-elastic body that is distorted more than the main elastic body in response to the same input is detected by the mold needle of the article loaded on the main elastic body. a force measuring device for calculating the load in the processing section based on the generated tension or compression force; a device for adding or subtracting a weight from the secondary elastic body; and a force measuring device for calculating the load in the processing section based on the generated tension or compression force; A first memory that stores the output, a second memory that stores the output of the processing section in a state where the weight is loaded on the auxiliary elastic body, and a difference in stored values between the first memory and the second memory is calculated. A mass meter comprising a subtraction section, a third memory that stores the output of the subtraction section, and a division section that divides the output of the processing section with an article loaded on the main elastic body by the value stored in the third memory. .