JPS6199820A - Setting method of body to be measured on measuring conveyor - Google Patents

Abstract

PURPOSE:To shorten an operation stabilization time and improve measurement accuracy and processing ability by stopping the conveyor after the time necessary for the arrival of the calculated center of the body to be measured at the center of the measuring conveyor, after the body passes through a reference point. CONSTITUTION:The time t2 required by the body X to pass through a measurement pint P2 on the carrying-in conveyor 20 is measured when the body X to be measured is conveyed to the measuring conveyor 10 by the carrying-in conveyor 20. The length l of the body X is calculated by a controller 30 from the time t2 and the conveyance speed of the conveyor 20 and the time t1 required by the body to pass through the center reference point P1 of the conveyor 10 by 1/2l is calculated by using the conveyance speed V1 of the conveyor 10. Then, when the front end of the body X passes through the reference point P1 by 1/2l, the controller 30 outputs an operation stop signal C to the motor 17 of a conveying device 12 of the conveyor 10. Consequently, the body X stops while set in the center of the conveyor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for setting objects to be weighed on a weighing conveyor used in a product weighing system, weight inspection system, or the like.

(Conventional technology) For supermarkets, the product packaging center etc. calculates the weight of the packaged product and calculates the price of the product based on the weighed weight value and a preset unit price, tare weight, etc. At the same time, a measurement pricing system is provided that prints the price, weight, etc. on a label and attaches it to the product. In addition, the production lines for various products are equipped with a weight inspection system that inspects the weight of the product in the final process.
Weighing conveyors are commonly used in these systems.

This weighing conveyor combines a belt conveyor-type or roller conveyor-type conveyance device for conveying objects to be weighed delivered from an upstream carry-in conveyor with a weighing device, and the weight of the conveyor and the weight on the conveyor are sent to the weighing device. The weight of the delivered object to be weighed is loaded thereon, but since the weight of the conveyance device is constant, the weight of the object to be weighed is measured.

However, in this type of weighing conveyor, when particularly high weighing accuracy is required, for example,
As shown in Publication No. 5, a so-called static weighing method is adopted in which the conveying device is stopped during weighing. That is, a detection device for detecting the presence of an object to be weighed is provided at a predetermined position on the weighing conveyor, and when the detection device detects that the object to be weighed has been conveyed to a predetermined position on the weighing conveyor, the detection device detects the presence of the object to be weighed at a predetermined position on the weighing conveyor. Then, the conveying device is stopped, and during this time, the weighing device waits for the operation to stabilize before weighing.

However, in the conventional weighing conveyor that performs static weighing as described above, as shown in the above publication,
The transport device is designed to stop when the detection device detects the front end (or "rear end") of the object to be weighed, so depending on the length of the object, the center of the object, that is, the center of gravity, may be transported. The conveyor will be stopped when the conveyor is not aligned with the center of the apparatus.In other words, if the front end of the object to be weighed is detected and the conveyor is stopped, if the object to be weighed is short, bacteria may approach the conveyor. If the object to be weighed is long, it will be set towards the rear.
If the objects to be weighed are set biased toward the front or rear of the conveyor, the stabilization time of the weighing device becomes significantly longer, and the throughput per unit time of the weighing conveyor or the system using the conveyor increases. Otherwise, measurement is performed before the operation of the measuring device becomes completely stable, resulting in a decrease in measurement accuracy. In addition, a moment acts on the weighing device, which also reduces weighing accuracy. In load cell type weighing devices in particular, so-called four-corner adjustment is required to reduce the drop in weighing accuracy caused by this moment. This will require high precision, which will increase costs.

(Object of the invention) The present invention deals with the above-mentioned situation in weighing conveyors that carry out static weighing, and it is possible to
By ensuring that the center of the object to be weighed is always set approximately at the center of the weighing conveyor, the operation stabilization time of the weighing device is shortened and processing capacity is improved without reducing weighing accuracy. When using a weighing device, the purpose is to eliminate the need to adjust the four corners of a load cell with particularly high precision, thereby reducing costs.

(Structure of the invention) A method for setting objects to be weighed on a weighing conveyor according to the present invention includes:
In order to achieve the above purpose, the present invention is characterized by the following configuration.

In other words, using the length of the object to be weighed which is known or determined in the previous step and the conveyance speed of the 1' conveyor in total, the measurement starts from the point at which the front or rear end of the object to be weighed passes a predetermined reference point. The measuring conveyor is configured to calculate the time required for the center of the object to reach approximately the center of the weighing conveyor, and to stop the weighing conveyor when this required time has elapsed from the time of passing the reference point. In short, if the length of the object to be weighed is 1, the transport speed of the weighing conveyor is vl, and the distance from the reference point to the center of the weighing conveyor is fo, then from the time to when the front end of the object to be weighed passes the reference point The time t1 required for the center to reach the center of the weighing conveyor is t1= (flo + f/2)
/V 1 (1), so if the weighing conveyor is stopped when the required time t1 has passed from the above point to, the weighing conveyor will always be on the weighing conveyor regardless of the length of the object to be weighed. It will be set in the center of

In this case, when the length of the object to be measured is unknown,
The length 1 of the object to be weighed is determined by measuring the time it takes for the object to be weighed to pass from the front end to the rear end at a predetermined measurement point provided on the carry-in conveyor disposed upstream of the weighing conveyor. In other words, if the measured passing time is t2 and the transport speed of the incoming conveyor is V2, then the length 1 of the object to be weighed is 1=v2・t2 (calculated in 21, and therefore the object to be weighed is the distance from the reference point. The time t1 until the center reaches the center of the weighing conveyor is the above (1
), From equation [2], t1=(fo+v2·tz/2)/Vt (3).

Also, if the reference point is set at the center of the weighing conveyor, J2
o-0, the required time t1 is t1=(V
2・t2)/2V1 (4).

Furthermore, when the length 1 of the object to be weighed is unknown, the conveyance speed v1 of the weighing conveyor and the conveyance speed v2 of the carry-in conveyor are
If they are equal, the required time t1 is calculated from the above equation (3) as t 1 = flo /v 1 +t 2 /2
[5] becomes. Here, when the time when the rear end of the object to be weighed passes the reference point, the required time 11' is t 1
'=j! o/v 1-t 2/2 (5'
).

After the front end or rear end of the object to be weighed passes the reference point, the required time t1. calculated by the above formula. t1'
If the weighing conveyor is stopped after , the object to be weighed will be set in the center of the weighing conveyor regardless of its length.

(Example) Examples of the present invention will be described below.

FIG. 1 shows a weighing conveyor system to which a first embodiment of the present invention is applied, and the system includes a weighing conveyor 10,
A carry-in conveyor 20 arranged upstream of the conveyor 10
and has. Further, the weighing conveyor 10 is composed of a weighing device 11 and a conveying device 12 installed on the weighing device 11. Furthermore, this conveying device 12 includes drive rollers 14 that are pivotally supported at both ends of a frame 13. and driven roller 15
A conveyor belt 16 is wound between the frame 1 and the frame 1.
The drive roller 14 is configured to be rotated by a motor 17 installed in the drive roller 3 via a transmission belt 18.

In addition, the carry-in conveyor 20 has a conveyor belt 23 wound between a drive roller 22 and a driven roller (not shown) which are respectively pivotally supported at both ends of the frame 21.
The drive roller 22 is configured to be rotated by a motor 24 attached to the drive roller 22 via a transmission belt 25.

On the other hand, this weighing and conveying system is equipped with a control device 30, and the control device 30 receives a signal from a first sensor 31 installed at the center (reference point P1) of the weighing conveyor 10 to determine a predetermined position of the carrying-in conveyor 20. A signal B from the second sensor 32 installed at the position (measurement point P2) is input. The first sensor 31 (the same applies to the second sensor 32) is connected to the weighing conveyor 10 (as shown in FIG.
It is composed of a pair of light emitters 31a and a light receiver 31b arranged oppositely on both sides of the carry-in conveyor 20), and the light emitter 31
When the light output from a is not input to the light receiver 31b,
That is, when an object to be measured exists between the light projector 31a and the light receiver 31b, the ON signal A (B) is output. Then, the control device 30 receives these signals A and B.
Based on this, the length of the object to be weighed and the timing to stop the weighing conveyor 10 are calculated, and signals C and D are sent to the motors 17 and 24 of the weighing conveyor 10 and the carry-in conveyor 20 to instruct them to stop and operate. is configured to output. In addition, the control device 30 includes a conveyor 10.20.
Input device 3 for inputting known numerical values such as the conveyance speed of
3 is connected, and also inputs the weight signal E from the weighing device 11 of the weighing conveyor 10 and sends it to the signal F.
It is designed to be sent to other devices as .

Next, the specific operation of this embodiment will be explained. still,
In this embodiment, the control device 30 is constituted by a microcomputer and operates according to the flowchart shown in FIGS. 3-4, so the explanation will be based on this flowchart.

First, the control device 30 resets the count value t of the built-in timer counter to 0 in step S1 in the flowchart of FIG. wait. This second sensor 32 is installed at a predetermined measurement point P2 on the loading conveyor 20 shown in FIG.
As shown in , when the front end X' of the object to be measured X reaches the measurement point P1, the signal B turns ON. From this point on, step S3. According to S4, the above signal B is turned off.
1 is repeatedly added to the count value t until the rear end of the object to be weighed The passage time t2 required for the entirety of X to pass through the measurement point P2 is obtained.

Next, in step S5, the control device 30 controls the passing time [
2, the time t1 required for the object to be weighed X to pass from the center reference point P1 of the weighing conveyor 10 to 1/2 of its total length is calculated according to the following formula % formula % (). This equation (a) is the above-mentioned equation (4), and calculates the length 1 of the object to be weighed from the passage time t2 of the measurement point P2 and the conveyance speed v2 of the carry-in conveyor 20,
Further, the time t1 required for 1/2 of this length 1 to pass through the reference point P1 at the center of the weighing conveyor 10 is calculated using the conveying speed v1 of the weighing conveyor 10.

Then, in step S6, the control device 30 sets the required time t1 to the count value t of the timer counter, and further, in step S7, the output signal A of the first sensor 31 is set to O.
Wait until it becomes N. This first sensor 31 is installed at a reference point P1 in the center of the weighing conveyor 10, and when the front end X' of the object to be weighed X reaches the reference point P1 as shown by the chain line (C) in FIG. At this point, the signal A is turned ON. Until the signal A turns ON, that is, until the front end X' of the object to be weighed X reaches the reference point P1, the object to be weighed after the object to be weighed In order to prevent this, a double riding prevention process is controlled in step S8. This control is performed in step S as shown in FIG.
1', when it is determined that the output signal B of the second sensor 32 on the carry-in conveyor 20 is turned ON, that is, when the conveyor 2
When the subsequent object to be weighed reaches measurement point P2 on 0, the carrying-in conveyor 20 is stopped in step 82'. Therefore, the subsequent object to be weighed waits in the state shown by the chain line (A) in FIG. 1 until the processing for the preceding object to be weighed X is completed.

However, the front end X' of the object to be weighed
When the control device 30 reaches the central reference point P1 and the output signal A of the first sensor 31 turns ON, the control device 30 performs step S9.
According to S10, 1 is subtracted from the count value (required time) 11 set in the timer counter in step S6, and this is continued in step S until the count value t1 becomes O.
11 is repeated while controlling the above-mentioned double-riding prevention process. Then, when the count value t1 becomes O, in other words, when the front end of the object to be weighed
2, the motor 1 of the conveying device 12 in the weighing conveyor 10
7, a signal C is output to stop the operation. As a result, the conveying device 12 is stopped, and the object to be weighed X is stopped in a state set in the center of the weighing conveyor 10, as shown by the chain line (D) in FIG.

Then, step 813. According to S14, while performing the double weighing prevention process, the amplitude of the signal E indicating the weight of the object to be weighed After waiting for the device 11 to become stationary and stable, the weight value indicated by the signal E is input. This weight value is used, for example, in a weighing system to calculate a price together with a unit price, a tare, etc., and is used in a weight inspection system to determine whether the weight is correct or not. When the weighing operation is completed as described above, the control device 30 outputs signals C and D to operate the motors 17 and 24 of the weighing conveyor 10 and the carry-in conveyor 20. Activate to weigh the next object to be weighed.

This embodiment is for the case where the length 1 of the object to be measured is unknown or not constant, and when the length 1 of the object to be measured is known, the second sensor 32 shown in FIG. It is not necessary to measure the length of the object to be weighed. In that case, the control device 3
0, it is sufficient to set t 1 = 1/2V 1 as the counter value (required time) tl of the timer counter in step S6 of FIG. 3, and execute only steps from step 86 onwards.

Next, a second embodiment of the present invention will be described.

In this embodiment, the conveyance speed of the weighing conveyor 40 and the conveyance speed of the carry-in conveyor 50 shown in FIG. has been done. The installation position P1' of this sensor 61 serves as both the reference point P1 and the measurement point P2 in the above embodiment, and is located at a distance of 1! from the center point PO' of the weighing conveyor 40. It is considered O. Then, the output signal A' from the sensor 61 is input to the control device 60, and the signal C',
D' is output.

Note that the other configurations are the same as those in the previous embodiment.

Next, the operation of this second embodiment will be explained according to the flowchart of FIG. 6. In step 81'', the control device 60 resets the count value t' of the timer counter to O, and then in steps S2 to $4''. According to the above count value t
' by repeatedly adding 1 to determine the time during which the sensor 61 is ON, that is, the reference point (measurement point) P on the loading conveyor 50.
Time t2 for the object to be measured X to pass through 1' from the front end to the rear end
Find ′. Then, in step S5'', according to the following formula % formula % (), the object to be weighed
After the rear end passes the reference point P1', its center reaches the center point Pa of the weighing conveyor 40, as shown by the chain line (to).
The time t1' required to reach ' is calculated, and this value is set as the count value of the timer counter in step 86''.

Then, the control device 60 next performs steps 87'' to 89''.
Accordingly, 1 is subtracted from the count value 11', and
This is repeated while performing the double loading prevention process until the count value t1' becomes O, and when t1'=o, a signal C is sent to stop the motor 41 of the weighing conveyor 40.
′ is output.

As a result, the weighing conveyor 40 is stopped, and the weighing object is set at the center of the conveyor 40 as shown by the chain line in FIG.

Then, in accordance with steps 8111 to 314'', as in the previous embodiment, wait until the weighing device 42 is stable and input the signal E' indicating the weight of the object to be weighed from the weighing device 42,
Move on to the next weighing operation.

(Effects of the Invention) As described above, according to the present invention, when an object to be weighed is set on a weighing conveyor used in a system or a weight inspection system, the measurement value is attached to the object to be weighed depending on its length. Regardless of the situation, it will always be set in the center of the weighing conveyor. As a result, the time required for the operation of the weighing device on the conveyor to stabilize is shortened, the throughput per unit time of the weighing conveyor or the above-mentioned system is improved, weighing accuracy is improved, and load cell type weighing When the device is used, the generation of moment due to the load of the object to be measured is prevented or reduced, so there is no need to adjust the four corners of the load cell with particularly high precision, and therefore costs are reduced. .

[Brief explanation of the drawing]

Figures 1 to 4 show a first embodiment of the present invention, where Figure 1 is a control system diagram, Figure 2 is a schematic plan view showing a sensor used in this embodiment, and Figures 3-4. is a flowchart diagram showing the operation. 5-6 show a second embodiment of the present invention, FIG. 5 is a control system diagram, and FIG. 6 is a flow chart diagram showing the operation. 10.40... Meter conveyor, 20.50... Loading conveyor, 30.60... Control device, Pl, P1'.
...Reference point, P2...Measurement point, X...Object to be measured. Applicant Goda Kouki Seisakusho Co., Ltd. 1itfmtIa61-Ra8Zυ(l) Figure 4

Claims (4)

[Claims] (1) Using the length of the object to be weighed which is known or determined in the previous step and the transport speed of the weighing conveyor, the object to be weighed is determined from the time when the front end or rear end of the object to be weighed passes a predetermined reference point. The object to be weighed on a weighing conveyor is characterized in that the time required for the center of the object to reach the center of the weighing conveyor is calculated, and the weighing conveyor is stopped when the required time has elapsed from the time of passing the reference point. How to set. (2) A measurement point is set up on the carry-in conveyor placed upstream of the weighing conveyor, and the time taken for the object to be weighed to pass through this measurement point from the front end to the rear end is measured, and this passing time and the conveyance of the carry-in conveyor are measured. A method for setting objects to be weighed on a weighing conveyor according to claim 1, characterized in that the length of the objects to be weighed is determined from the speed. (3) While the reference point is set approximately at the center of the weighing conveyor, the time required for conveying 1/2 of the length of the object to be weighed is determined based on the conveyance speed of the weighing conveyor and the length of the object to be weighed. The weighing conveyor according to claim 1 or 2, characterized in that the weighing conveyor is stopped when the required time has elapsed after the front end of the object to be weighed passes the reference point. How to set the object to be weighed. (4) When the transport speeds of the carry-in conveyor and the weighing conveyor are equal, calculate the length of the object to be weighed from the passing time of the measurement point on the carry-in conveyor, and using this measurement point as a reference point, move the weighing conveyor from the reference point. From the distance to the approximate center of the weighing object, the length of the object to be weighed, and the transport speed of the conveyor, it is determined that the center of the object to be weighed will be at the approximate center of the weighing conveyor from the time when the front or rear end of the object to be weighed passes the reference point. The weighing conveyor according to claim 2, characterized in that the time required to reach the center is calculated, and the weighing conveyor is stopped when this required time has elapsed from the time when the weighing conveyor passes the reference point. How to set the object to be weighed.