JPS60238722A - Quantity scale - Google Patents

Abstract

PURPOSE:To shorten a measuring time and to improve accuracy by transmitting a feeding signal from a comparing part every time passing through numerous set weights set up in advance and by measuring with the control of the feed from a feeding device by the size of a signal. CONSTITUTION:A driving shaft 18 to open and close the lower end of a storage hopper 12 of a feeding device 10 is connected to a servomotor 22 and potentiometer 24 and the outputs of the potentiometer 24 and of D/A convertor are inputted to a servo amplifier 26. The motor 22 is also driven by the amplifier 26 so as to make the potential difference of both inputs zero and the quantity according to the output of the convertor 28 only is thrown into a measuring hopper 30 from a throwing-in gate 14. The measuring signal is then functioned as a comparing part by its being fed to a microcomputer 40 via A/D convertor 38 and also is made to control the opening and closing of the gate 14 and a discharging gate 42 as a controlling part. The vibration of a signal at the time of changing a throwing-in can be thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metering scale that, for example, charges a fixed amount of an article into a container and discharges a fixed amount of the article from a container containing the article.

Conventionally, the type of metering scale that charges a fixed amount of goods into the container described above has a hopper into which the goods are placed below a storage hopper that stores the goods, and this hopper weighs the goods put into the hopper. A measuring section is provided to initially charge the articles into the hopper at a large flow rate, and this is hereinafter referred to as large loading. ), when the weighing signal of the weighing section becomes equal to or higher than the first set weight W11,
When the flow rate is decreased (hereinafter referred to as "medium loading") and the metering signal reaches the second set weight W2 or more, the flow rate is further decreased (hereinafter referred to as "small loading"), and the metering signal is set to the second set weight W2. There were some products that stopped feeding when the weight exceeded the set weight W3.

In such a quantitative scale, the number of switching points for the input flow rate is two: switching from large input to medium input, and switching from medium input to small input.
Since there is only one turn, the flow rate change when switching is large.
As shown by reference numeral 1.2 in the figure, vibrations were occurring in the weighing signal. Such vibrations adversely affect the measurement and make it impossible to obtain satisfactory accuracy, so it is necessary to wait until the vibrations subside, prolonging the measurement time and causing a decrease in performance.

In addition, the flow rate of goods input from the storage hopper can be adjusted by
For example, a plurality of sheets 7-r Ic provided at the lower end of the storage hopper
;h l'J fl m m D CI X 5 A
Line 191' In other words, it was performed in stages and no accumulation was made, making it troublesome to adjust the flow rate change.

The object of the present invention is to provide a quantitative weighing machine that solves both of the above problems.

Therefore, as shown in FIG. 2, the present invention includes a supply device 4 that controls the supply amount of articles to be continuously supplied according to the magnitude of a supply control signal, and a metering device for weighing the articles supplied from the supply device 4. a weighing section 6 that compares the weighing signal of the weighing section 6 with a large number of predetermined set weights, and generates the supply control signal having a different magnitude each time the weighing signal exceeds each of the set weights. The configuration includes a section 8.

In the quantitative scale configured in this way, the weighing signal from the weighing section 6 is compared with a large number of set weights in the comparing section 8, and each time the weighing signal exceeds each set weight, the comparing section 8 generates a feed control signal based on the supply control signal. The amount of articles supplied from the article supply device 4 is controlled. Therefore, the number of switching points in the supply amount can be increased compared to conventional systems, and the change in the supply amount at the time of switching can be reduced.
No vibrations occur in the weighing signal. Therefore, there is no need to wait until the vibrations subside, and the measuring time can be shortened.

Furthermore, since the supply device 4 adjusts the supply amount according to the magnitude of the supply control signal, even when the type of article stored in the supply device is changed and the supply flow rate is changed, the supply amount is adjusted according to the magnitude of the supply control signal. This is very easy to do, just by changing the magnitude of the control signal.

Hereinafter, this invention will be explained in detail based on one embodiment shown in FIGS. 3 to 5. In FIG. 3, supply device]0
has a sump hopper 12. At the lower end opening of this storage hopper 12, a charging material 14 is provided so as to be rotatable about a drive shaft 18 in the direction of arrow 16 so as to open and close the lower end opening. The drive shaft 18 of this input gate 14 is
It is coupled to a rotating shaft of a servo motor 22 via a speed change gear 20, and a potentiometer 24 is also coupled to this rotating shaft. The output of this potentiometer 24 is input to a servo amplifier 26. The servo amplifier 26 is also supplied with an output from the D/A converter 2. The servo amplifier 26 drives the servo motor 22 so that the potential difference between the two human forces becomes zero. As a result, the input gate 14 is opened by an amount corresponding to the output of the VA converter on the second day.

Due to the opening of the input gate 14, the storage hopper 12
Items fall from the ground. This fallen article is thrown into a weighing hopper 30 provided below the storage hopper 12. This weighing hopper 30 has load cells 32 and 32 as a weighing section.
is provided. The analog weighing signals from these load cells 32 and 32 are added by an adder 34, then amplified by an amplifier 36, converted to a digital weighing signal by an A/D converter 38, and supplied to a microcomputer 40.

The microcomputer 40 functions as a comparison unit and also functions as a control unit for the discharge gate 42 that opens and closes the upper end opening of the weighing hopper 30. Note that 44 is an air cylinder for driving the discharge gate 42.

Next, each function of the microcomputer 40 will be explained based on the flowchart shown in FIG. First, in step 46, the key switch 48 is used to set the flow rates GA to GE,
The switching weights WA to WE are set respectively.

Next, in step 50, it is determined whether a closing start signal has been input from the key switch 48 or from the outside. If no input has been made, step 50 is repeated. Once input, the process moves to step 52, where the flow rate GA is input to the D/A converter 2.
Supply to 8. As a result, the input gate 14 is opened in response to the output from the flow converter 28 as described above, and the article is loaded from the storage hopper 12 into the weighing hopper 30 at a flow rate G'A.

Next, in step 54, it is determined whether the digital weighing signal W of the A/D converter 38 is equal to or greater than the set weight WA. CB is supplied to the D/A converter 28. This changes the opening degree of the input gate 14,
The flow rate becomes GB. Then, in step 58, it is determined whether or not the digital weighing signal W is equal to or greater than the set weight WB. If not, step 5 is repeated, and if it is equal to or greater, the process moves to step 6o, and the flow rate GC is switched to the converter 2. supply This changes the opening degree of the input gate, and the flow rate reaches the GC. Then, in step 62, it is determined whether the digital meter Ji signal W is greater than or equal to the set weight WC,
If not, repeat step 62; if not, proceed to step 64, and supply the flow rate GD to the D/A converter 28. As a result, the opening degree of the injector 14 changes, and the flow rate becomes GD. Next, in step 66, it is determined whether the digital weighing signal W is greater than or equal to the set weight WD,
If not, repeat step 6, and if it is, move to step 6 and supply the flow rate GE to the D/A converter on day 2. As a result, the opening degree of the input gate 14 changes, and the flow rate becomes GE. Then, in step 70, it is determined whether the digital weighing signal W is greater than or equal to the set weight WE, and if it is not greater than the set weight, step 70 is repeated, and if it is greater than the set weight, a supply stop signal is supplied to the D/A converter 28 in the step match. do. As a result, the input gate 14 is closed,
Supply of goods will be stopped.

Everything up to this point functions as a comparison section. FIG. 5 shows the changes in the weighing signal up to this point. As can be seen from this, no vibration is caused by the multistage switching.

Next, in step 74, an open signal is provided to the air cylinder 44 to open the discharge gate 42. And step 76
It is determined whether the discharge time has elapsed or not. If the discharge time has not elapsed, step 76 is repeated, and if it has elapsed, step '7 is performed.
At B, a close signal is supplied to the air cylinder 44 to close the discharge gate 42. Everything up to this point functions as a discharge gate control section.

Next, in step 80, it is determined whether or not the input is to be continued, and if it is to be continued, the process returns to step 50, and if not, it is stopped.

In the above embodiment, the flow rate was switched in five stages, but it may be switched in more stages. In the above example, GA
All of GEXWA to WE are set, but as shown in Figure 6, the first and last flow rates GA, GE and the first, second to last, and last switching weights WA, WD.

The flow rate and switching weight between these may be calculated by the microcomputer 40 by setting the WE da i. In that case, the set weight increases by △W (WD-WA/n) in order,
The switching weight increases in turn by ΔG(GA-CB/?Z+1). However, n is the number of sections between WA, WD.

In the above embodiment, the load cell (load cell) v32.32 is provided on the weighing hole 30, but it may be provided on the sump hopper 12 side.

In that case, since the weighing signal decreases as the articles are loaded, the switching weights WA to WE need to be set to decrease in this order. In addition, in the above embodiment, this invention was applied to a type of metering scale that allows articles to fall naturally, but it can also be implemented to a type of metering scale that feeds articles using a screw tweeter or an electromagnetic feeder. Good too. Further, in this embodiment, a servo motor is used as the drive unit, but a noclune motor positioner, a multi-point positioning cylinder, etc. may be used instead.

[Brief explanation of drawings]

Figure 1 is a diagram showing changes in the weighing signal of a conventional quantitative scale, Figure 2
3 is a block diagram of an embodiment of the quantitative scale according to the present invention, FIG. 4 is a flowchart of the embodiment, and FIG. 5 is a diagram of the weighing signal of the embodiment. FIG. 6 is a diagram showing changes in the weighing signal of another embodiment. 4... Article supply device, 6... Measuring section, 8... Comparison section. Patent applicant: Daiwa Seiko Co., Ltd. Representative: Satoshi Shimizu and two other talented people. 1 year old 4 [! 1 No. 6 Figure

Claims (1)

[Claims] (1) A feeding device that controls the amount of articles to be continuously supplied according to the magnitude of a supply control signal, a measuring section that weighs the articles supplied from this feeding device, and a measuring section that controls the measuring signal of this measuring section. A quantitative weigher comprising: a comparison unit that compares a large number of predetermined set weights and generates the supply control signal having a different magnitude each time the weighing signal exceeds each of the set weights.