Weighing and packaging system and combination scale used therefor

Abstract

To enable automatic optimization of coordination between a combination scale and a packaging machine.SOLUTION: A combination scale disclosed herein does not require operating speed settings but automatically optimizes a stabilization time of a weighing hopper for weighting articles based on a period of an article discharge request signal transmitted from a packaging machine.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a weighing and packaging system that weighs and packages items, and a combination weigher used therein. [Background technology]

[0002] A typical combination weigher has a dispersion feeder that radially disperses and transports items supplied from above the center, and is configured to have multiple straight feeders arranged around the dispersion feeder to further transport the items dispersed and transported by the dispersion feeder outward, and to supply items to multiple weighing units arranged corresponding to each straight feeder.

[0003] The weighing unit includes a plurality of supply hoppers that temporarily store and discharge items supplied from the linear feeder, and a plurality of weighing hoppers that store the items discharged from each supply hopper and weigh them.

[0004] The combination scale performs a combination calculation to select a combination of weighing hoppers from which an item should be discharged, where the combined weight, which is the total weight of the weights of the items in each weighing hopper, falls within a predetermined weight range based on the target combined weight.

[0005] Items are discharged from the weighing hoppers of the appropriate combination selected by this combination calculation, and the discharged items within a specified weight range are temporarily stored in a collection hopper and then discharged to the packaging device in response to an item discharge request signal from the packaging device.

[0006] In such a weighing and packaging system, in order to enable coordinated operation between the combination scale and the packaging machine, for example, the packaging machine is set as the master device and the combination scale is set as the slave device, and the operating speed of the packaging machine is set to be slower than that of the combination scale, and when the packaging machine is ready to package an item, the packaging machine outputs an item discharge request signal to the combination scale requesting that the item be discharged.

[0007] In a combination weigher, before an item discharge request signal is input from the packaging machine, a predetermined number of weighing hoppers are prepared in which items have been added and the weighing stabilization time has passed, so that combination accuracy can be maintained.When an item discharge request signal is input from the packaging machine, a combination calculation is performed to find a combination of weighing hoppers within a predetermined weight range, and the items are discharged from the weighing hoppers to the packaging machine, and an item discharge signal indicating that the items have been discharged is output to the packaging machine.

[0008] In such a weighing and packaging system, fluctuations occur in the timing at which the control units of the weighing machine and packaging machine recognize the exchanged item discharge signal and item discharge request signal.

[0009] If there is a fluctuation in the timing of recognizing these signals, it becomes difficult to set the operating speeds of both the weighing machine and the packaging machine to the same speed.

[0010] For this reason, for example, Patent Document 1 proposes a control method that allows the combination weigher and packaging machine to be operated at the same operating speed without causing a significant decrease in actual speed. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent Publication No. 2008-175718 Summary of the Invention [Problem to be solved by the invention]

[0012] In the weighing and packaging system of the present invention, when the packaging machine and the combination weigher are operated in conjunction with each other, the packaging machine is set to have a slower operating speed than the combination weigher.

[0013] In a combination weigher, a predetermined number or more weighing hoppers that have completed weighing items are secured before an item discharge request signal is input from the packaging machine, and in response to the item discharge request signal input from the packaging machine, a combination calculation is performed to discharge items from the weighing hoppers selected for the combination and output an item discharge signal to the packaging machine.

[0014] The packaging machine checks the article discharge signal input from the combination weigher and performs packaging operations for the articles discharged from the combination weigher.

[0015] The combination weigher has an operating speed setting and performs combination calculations after receiving an item discharge request signal, but since combination accuracy cannot be maintained unless a predetermined number of weighing hoppers have completed weighing, it is necessary to set the operating speed faster than the input period of the item discharge request signal.

[0016] However, in the above configuration, - In order to increase the operating speed, shortening the time it takes for the weighing hopper to stabilize after items are placed in it results in a decrease in weighing accuracy. Furthermore, because the situation on the production line changes, there is the issue that waiting time on the combination weigher side, such as waiting for the input of an item discharge request signal, is a lost opportunity to improve operational capacity and weighing accuracy. Furthermore, it is time-consuming for operators to frequently adjust the operating speed according to the production line situation, and there is also the issue that the fewer operating parameter settings there are and the less adjustment work required, the better.

[0017] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a weighing and packaging system that reduces the loss of opportunities to improve operational capacity and weighing accuracy even when the situation on the production line changes, and that is easy to adjust, as well as a combination weigher for use in such a system. [Means for solving the problem]

[0018] In the weighing and packaging system of the present invention according to claim 1, a combination weigher that combines and measures the weight of articles and discharges them; a packaging machine that packages the items discharged from the combination weigher; Including, The combination weigher has a plurality of weighing hoppers that temporarily store items and weigh the weight of the stored items, and in response to an input of an item discharge request signal from the packaging machine, combines and calculates the weights of the items stored in the plurality of weighing hoppers, selects a weighing hopper that is a combination within a predetermined weight range, and outputs an item discharge signal to the packaging machine indicating that the items should be discharged from the selected weighing hopper to the packaging machine, thereby discharging the items.

[0019] In a weighing and packaging system, the packaging machine outputs the item discharge request signal to the combination weigher as a signal indicating that preparations for packaging the items discharged from the combination weigher have been completed and that the packaging machine requests the combination weigher to discharge the items, The combination weigher is characterized in that the weighing stabilization time after the articles are put into the weighing hopper of the combination weigher is automatically determined and updated at the input period of the article discharge request signal from the packaging machine without setting the operating speed related to the operation of the combination weigher.

[0020] With regard to the above-mentioned features, in a weighing and packaging system in which a packaging machine is used as the master device and a combination weigher is used as the slave device, the speed of the weighing and packaging system is determined by the speed of the packaging machine, making it unnecessary to set the speed of the combination weigher, which is a feature of the present invention.

[0021] The actual weighing speed of the combination weigher is determined by the weighing stabilization time set in step S88 of the flowchart in FIG. 7, which will be described later in the embodiment section.

[0022] In the weighing and packaging system of the present invention, the operating speed of the combination weigher is not set; instead, the control unit automatically determines and updates the weighing stabilization time after an item is placed in the weighing hopper at the period of the item discharge request signal from the packaging machine.

[0023] If the weighing stabilization time is shortened, the weighing speed will be increased because the weighing hopper that can participate in the combination can complete weighing earlier.

[0024] The shorter the weighing stabilization time, the worse the weighing accuracy, so there is an allowable limit. The longer the weighing stabilization time, the better the weighing accuracy. The more weighing hoppers that can participate in the combination, the better the combination accuracy.

[0025] The period of the packaging machine's item discharge request signal may be the average of N number of such item discharge request signals, or may be a moving average. If there is a fluctuation in the period that exceeds the allowable value, the weighing stabilization time is changed. If an item discharge request signal that deviates significantly from the existing stored period is input, it is determined that there is a problem on the packaging machine side, and the input signal is ignored.

[0026] To maintain a predetermined combination accuracy, a predetermined number of weigh hoppers that have completed weighing are required to participate in the combination calculation. Therefore, when performing the combination calculation, it is necessary to determine whether there are any weigh hoppers that have completed weighing.

[0027] In the present invention according to claim 2, the minimum metering stability time at which metering accuracy can be maintained is set as the metering stability time, and if the metering stability time calculated using the input period multiplied by 1 is shorter than the minimum metering stability time, the metering stability time is calculated using the input period multiplied by 2. In this embodiment, this is described in steps S84 to S88 in Fig. 7. If single-shift operation is not possible, the metering stability time is set based on double-shift operation. Furthermore, if double-shift operation is not possible, the metering stability time may be set based on triple-shift operation.

[0028] In the present invention according to claim 3, if there is no weighing hopper for which a predetermined number of stable weighing times have elapsed, no combination calculation is performed. This is described in step S11 in the embodiment. This is to maintain the combination accuracy.

[0029] A fourth aspect of the present invention provides a combination weigher for use in the weighing and packaging system according to the first aspect. [Effects of the Invention]

[0030] The present invention can automatically maximize the weighing capacity, weighing accuracy, and combination accuracy in accordance with the production status of the line. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic diagram of a weighing and packaging system in which the present invention is implemented. [Figure 2] 1 is a circuit block diagram of a weighing and packaging system in which the present invention is implemented. [Figure 3] 1 is an overall flowchart of the present invention. [Figure 4] 4 is a flowchart of the control of the linear feeder in FIG. 3. [Figure 5] 4 is a flowchart of the supply hopper control of FIG. 3. [Figure 6] 4 is a flowchart of the measurement control in FIG. 3. [Figure 7] 4 is a flowchart of the operation parameter change process of FIG. 3. [Figure 8] 4 is a flowchart of weighing hopper control in FIG. 3. [Figure 9] 10 is a timing chart of a single shift operation. [Figure 10] 10 is a timing chart of double shift operation. DETAILED DESCRIPTION OF THE INVENTION

[0032] A weighing and packaging system and a combination scale used therein according to an embodiment of the present invention will be described in detail below. Fig. 1 is a schematic diagram of a weighing and packaging system according to an embodiment of the present invention.

[0033] In FIG. 1, reference numeral 1 denotes a combination weigher, 2 denotes a packaging machine, 3 denotes a supply device, and 4 denotes an operation setting display device.

[0034] In the combination weigher 1, 11 denotes a level sensor, 12 denotes a dispersion feeder, 13 denotes a linear feeder, 14 denotes a supply hopper, 15 denotes a weighing hopper, 16 denotes the device body, and 17 denotes a collecting chute.

[0035] The level sensor 11 is a sensor, such as an ultrasonic sensor, that detects the amount of articles being fed from the supply device 3 into the dispersion feeder 12. The level sensor 11 detects the layer thickness of the articles on the dispersion feeder 12 to detect the amount of articles present in the dispersion feeder 12, and turns the supply operation of the supply device 3 on and off to control the amount of articles supplied to the dispersion feeder 12. Other methods for detecting the amount of articles present in the dispersion feeder 12 include image recognition using an imaging device, and a method in which the dispersion feeder 12 itself is supported by a load cell, which is a weighing sensor, and the weight of the articles loaded on the trough of the dispersion feeder 12 is measured.

[0036] The dispersion feeder 12 is a cone-shaped feeder that conveys the articles fed from the feeder 3 outward.

[0037] A plurality of linear feeders 13 are arranged radially around the dispersion feeder 12, and are feeders that convey articles conveyed from the dispersion feeder 12 outward by vibration.

[0038] The supply hopper 14 is a hopper that temporarily stores and discharges the articles from the linear feeder 13.

[0039] A plurality of weighing hoppers 15 are arranged below each of the supply hoppers 14 in correspondence with each supply hopper 14, and measure the weight of the articles discharged from each of the supply hoppers 14.

[0040] The device main body 16 includes a weighing sensor 16 a, which detects the weight of the articles in the weighing hopper 15 .

[0041] The collecting chute 17 is disposed below and around each weighing hopper 8 .

[0042] A combination of weighing hoppers 15 is selected from the weighing hoppers 15 such that the combined weight of the articles falls within a predetermined weight range, and the articles discharged from the selected combination of weighing hoppers 15 are slid down to the center below a collecting chute 17 and collected.

[0043] The packaging machine 2 is disposed below the collecting chute 17 and packages the articles discharged from the collecting chute 17.

[0044] FIG. 2 is a circuit block diagram of a weighing and packaging system in which the present invention is implemented.

[0045] In FIG. 2, the combination weigher 1 includes, as a block circuit, a combination weigher main body 1a and a combination weigher control unit 1b.

[0046] The combination weigher main body 1a includes a level sensor 11, a dispersion feeder 12, a linear feeder 13, a supply hopper 14, a weighing hopper 15, and a weighing sensor 16a.

[0047] The combination weigher control unit 1b includes a converter b1, feeder drive circuits b2 and b3, a supply hopper discharge gate drive circuit b4, a supply hopper drive circuit b5, an A / D converter b6, and a cPU b7.

[0048] CPU b7 includes memory b8.

[0049] The combination weigher control unit 1b includes interfaces (I / F) b9 and b10.

[0050] 3 is a flowchart showing the overall operation of the weighing and packaging system according to an embodiment of the present invention. The control unit 1b of the combination weigher 1 is the main controller in each step of this flowchart. The control unit 1b controls the entire weighing and packaging system, including the combination weigher 1 and packaging machine 2.

[0051] In step S1, the user selects the type of item to be weighed by the combination weigher 1.

[0052] In step S2, the user operates the operation setting display device 4 to select an operating parameter stored in the memory b8 of the control unit 1b of the combination weigher 1. Operating parameters include, for example, the weighing stabilization time, minimum weighing stabilization time, minimum number of weighing hoppers participating in the combination, linear feeder drive time, and weighing hopper open time. In the present invention, the weighing stabilization time is updated, but when operation begins, the weighing stabilization time used in the previous operation or the default weighing stabilization time is used. The weighing stabilization time varies depending on the item. For items that bounce around in the weighing hopper, the weighing stabilization time is made longer than usual.

[0053] In step S3, it is determined whether the operation setting display device 4 has been operated to turn on the operation.

[0054] In steps S4 to S8, the supply device 3, the dispersion feeder 12, the linear feeder 13, the supply hopper 14, and the weighing hopper 15 are controlled, respectively.

[0055] In step S9, it is determined whether an article discharge request signal has been input from the packaging machine 2.

[0056] In step S10, if it is determined in step S9 that an article discharge request signal has been input from the packaging machine 2 to the combination weigher 1 (YES), an operating parameter change process is performed. The operating parameter change process will be described in detail with reference to the flowchart in FIG.

[0057] In step S11, it is determined whether or not there are a predetermined number or more weighing hoppers 15 that have completed weighing. In order to maintain the combination accuracy, there must be a predetermined number or more weighing hoppers that can participate in the combination.

[0058] In step S12, a calculation is performed to combine the weights of the items in the weighing hoppers 15 to select a weighing hopper 15 that has completed weighing in step S11 and has a weight combination that falls within the appropriate range.

[0059] In step S13, the weighing hoppers 15 are selectively controlled based on the results of the combined calculation of the weights of the articles in the weighing hoppers 15 in step S12.

[0060] In step S14, after selecting multiple weighing hoppers in step S13, it is determined whether or not the operation is OFF. If the control unit 1b determines YES that the operation is OFF, it returns to step S1 and weighs the next item type, and if it determines NO that the operation is not OFF, it returns to step S4.

[0061] 4 is a control flowchart of the linear feeder 13. The main controller in each step of this flowchart is the control unit 1b of the combination weigher 1.

[0062] In step S21, the number k is selected from the numbers 1 to n of the linear feeders 13.

[0063] In step S22, it is determined whether or not there is a drive command for the linear feeder 13 numbered k.

[0064] In step S23, if it is determined in step S22 whether or not there is a drive command from control unit 1b to linear feeder 13 numbered k, a time timer for linear feeder 13 numbered k is set. This time timer is the drive time for linear feeder 13 numbered k.

[0065] In step S24, the linear feeder 13 with the number k is driven and controlled in accordance with the time timer.

[0066] In step S25, the drive command for the linear feeder 13 numbered k is controlled to be OFF.

[0067] In step S26, the flag indicating that the linear feeder 13 of number k is in operation is turned ON.

[0068] Although the drive command for the linear feeder 13 numbered k is controlled to be OFF in step S25, the driving flag for the linear feeder 13 numbered k is turned ON in step S26 for the purpose of timer control.

[0069] In step S27, the linear feeder 13 to be controlled is changed from the linear feeder 13 with the number k to the linear feeder 13 with the number k+1.

[0070] In step S28, it is determined whether the number of control targets of the linear feeder 13 numbered k is n+1. If it is not n+1 or more, the process returns to step S22; if it is n+1 or more, the process returns, i.e., the linear feeder control program is exited.

[0071] Again, in step S22, it is determined whether or not there is a drive command for the linear feeder 13 numbered k. If it is determined to be negative (NO) in step S22, the process proceeds to step S29.

[0072] In step S29, it is determined whether or not the driving flag of the number k straight feeder 13 is ON. If it is determined that the driving flag of the number k straight feeder 13 is ON, the process proceeds to step S30.

[0073] In step S30, the drive time timer of the number k linear feeder 13 is decremented. The drive time timer of the number k linear feeder 13 is decremented for timer control.

[0074] In step S31, it is determined whether or not the drive time timer of the linear feeder 13 numbered k has timed out. If it is determined in step S31 that the drive time timer has timed out and YES, the process proceeds to step S32.

[0075] In step S32, the driving of the linear feeder 13 numbered k is controlled to stop.

[0076] In step S33, the driving flag of the linear feeder 13 numbered k is turned OFF, and the process proceeds to step S27.

[0077] Fig. 5 is a detailed flowchart of the supply hopper control in Fig. 3. The control unit 1b of the combination weigher 1 is the main controller in each step of this flowchart.

[0078] In step S40, the supply hopper control program sets the linear feeder 13 with the number k as the control target.

[0079] In step S41, it is determined whether or not an open / close command flag for the discharge gate of the number k supply hopper 14 is set. The open / close command flag for the discharge gate of the number k supply hopper 14 is a flag that is set when the discharge gate of the weighing hopper k is opened or closed.

[0080] In step S42, the control unit 1b of the combination weigher 1 controls the opening and closing of the discharge gate of the supply hopper 14 numbered k, since it determined in step S41 that the open / close command flag for the discharge gate of the supply hopper 14 numbered k exists.

[0081] In step S43, the control unit 1b of the combination weigher 1 turns OFF the discharge command gate open / close command flag of the supply hopper 14 numbered k.

[0082] In step S44, the flag for starting to feed articles to the number k weigh hopper 14 is turned ON. Turning ON the flag for starting to feed articles to the number k weigh hopper 14 means that the weighing stabilization time has started.

[0083] In step S45, the drive command for the linear feeder 13 numbered k is turned ON. Here, turning ON the drive command for the linear feeder 13 means that the supply hopper 14 has become empty and an article is to be supplied from the linear feeder 13.

[0084] In step S46, the number of the linear feeder 13 to be controlled is incremented from k to k+1.

[0085] In step S47, it is determined whether the number of the linear feeder 13 to be controlled is n+1, which means that linear feeders with numbers up to n are processed.

[0086] Fig. 6 is a flowchart of the weighing control in Fig. 3. The main controller in each step of this flowchart is the control unit 1b of the combination weigher 1.

[0087] In step S50, the weighing hopper 15 with the number k is set as the control object.

[0088] In step S51, it is determined whether or not the start flag for putting goods into the number k weigh hopper 15 is ON. If it is determined in step S51 that the start flag for putting goods into the number k weigh hopper 15 is ON, the process proceeds to step S52.

[0089] In step S52, a timer is set for the weighing stabilization time of the weighing hopper 15 numbered k. In step S53, the weighing stabilization waiting time flag of the weighing hopper 15 numbered k is turned ON. In step S54, the flag for starting to feed articles to the weighing hopper 15 numbered k is turned OFF.

[0090] In step S55, the number of the weighing hopper is set to (k+1).

[0091] In step S56, it is determined whether the weighing hopper number is n+1, YES, or NO. If NO, the process returns to step S51, and if YES, the process returns.

[0092] In step S57, it is determined whether the weighing stabilization waiting flag of the weighing hopper k is ON (yes or no). If the determination in step S57 is YES, the process proceeds to step S58.

[0093] In step S58, the weighing stabilization time timer of the weighing hopper k is decremented.

[0094] In step S59, it is determined whether the weighing stabilization time timer of the weighing hopper k has timed out (yes, no). If the determination is YES, the process proceeds to step S60.

[0095] In step S60, the weighed value of weigh hopper k is set. In step S61, the weighing stabilization time waiting flag of weigh hopper k is turned OFF, and the process proceeds to step S62.

[0096] In step S62, weighing hopper k is set as a valid weighing hopper (a weighing hopper that can participate in the combination calculation).

[0097] The process proceeds from step S62 to step S55. If the determination in step S57 is NO, the process proceeds to step S55.

[0098] Fig. 7 is a detailed flowchart of the operation parameter change process of Fig. 3. The main control unit in each step of this flowchart is the control unit 1b of the combination weigher 1.

[0099] In step S71, it is determined whether the flag indicating that the time interval of the item discharge request signal is being measured is ON. If the flag is not ON, that is, if the time interval of the item discharge request signal is not being measured, the determination is NO, and the process proceeds to step S72.

[0100] In step S72, a flag indicating that the time interval of the article discharge request signal is being measured is turned ON.

[0101] In step S73, a timer for a flag for detecting the time interval between input of an article discharge request signal from the packaging machine to the combination weigher is started.

[0102] In step S74, the first detection time value of the article discharge request signal is set to "0".

[0103] In step S75, the number of times the time interval between the article discharge request signals is measured and detected is set.

[0104] In step S76, the interval storage point for the article discharge request signal is initialized.

[0105] Step S77 is a step to which the process proceeds if it is determined in step S71 that the flag for measuring the time interval of the article discharge request signal is ON. In step S77, the detection timer value of the current article discharge request signal is recorded.

[0106] In step S78, the initial timer value is subtracted from the current timer value for detecting the article discharge request signal, which corresponds to the interval time between article discharge request signals.

[0107] In step S79, it is determined whether the interval between the item discharge request signals is within a predetermined time. If the interval between the item discharge request signals is within the predetermined time, the determination is YES and the process proceeds to step S80.

[0108] In step S80, the number of times the article discharge request signal has been detected is incremented by +1, and the process proceeds to step S81.

[0109] In step S81, the interval time of the current article discharge request signal is stored, and the next storage point is set.

[0110] In step S82, it is determined whether the number of times the article discharge request signal has been detected has reached a predetermined number. If the number of times the article discharge request signal has been detected has not reached the predetermined number, the process determines NO and returns, but if the number of times has reached the predetermined number, the process determines YES and proceeds to step S83.

[0111] In step S83, the stored N article discharge request signals are averaged over N.

[0112] In step S84, the temporary weighing stabilization time is determined by subtracting the weighing hopper gate opening time from the cycle time (the time interval between input of an article discharge request signal from the packaging machine to the combination weigher).

[0113] In step S85, it is determined whether the provisional weighing stabilization time is equal to or greater than the minimum weighing stabilization time. The determination in step S85 is a branching point between single-shift operation and double-shift operation, which will be described later. If the provisional weighing stabilization time is not equal to or greater than the minimum weighing stabilization time, the answer is NO, and the process proceeds to step S86. If the provisional weighing stabilization time is equal to or greater than the minimum weighing stabilization time, the answer is YES, and the process proceeds to step S88.

[0114] In step S86, the temporary weighing stabilization time is determined by subtracting the weighing hopper gate open time from the cycle time (input period) X2. The cycle time x 1 is single-shift operation, but the cycle time x 2 is a situation where double-shift operation is unavoidable.

[0115] In step S87, it is determined whether the provisional metering stabilization time is equal to or greater than the minimum metering stabilization time. If it is equal to or greater than the minimum metering stabilization time, the process proceeds to step S88, and if it is not equal to or greater than the minimum metering stabilization time, the process proceeds to step S90.

[0116] In step S88, the provisional measurement stabilization time is set as the formal measurement stabilization time, and the process proceeds to step S89.

[0117] In step S89, the packaging machine ready signal interval measurement flag is turned OFF.

[0118] In step S90, it is determined that the provisional stabilization time in step S87 is not equal to or greater than the minimum stabilization time, and an alarm is displayed.

[0119] In the above description, One cycle time is the interval between item discharge request signals. Weighing stabilization time = 1 cycle time - weighing hopper open time, but in reality this is the time minus the system clock of the CPU in the control unit 1b of the combination weigher, the combination calculation time (several ms), etc. The minimum stabilization time is the time it takes for the weighing to stabilize, and a shorter time means that there is unacceptable fluctuation. The longer the weighing stabilization time, the better the weighing accuracy.

[0120] The cycle period is measured and the stabilization time is automatically updated right at the start of each shift, until the very end of the cycle, in order to maximize weighing accuracy.

[0121] FIG. 8 is a flowchart of the weighing hopper control of FIG.

[0122] Step S91 is similar to step S50.

[0123] In step S92, it is determined whether or not there is a command to open or close the discharge gate of weighing hopper k. If it is determined that there is a command to open or close the discharge gate, the process proceeds to step S93.

[0124] In step S93, the opening and closing of the discharge gate of the weighing hopper 15 numbered k is controlled.

[0125] In step S94, the discharge gate open / close command for the weighing hopper 15 numbered k is turned OFF.

[0126] In step S95, the discharge gate open / close command flag of the supply hopper 14 numbered k is turned ON.

[0127] In step S96, the number of the supply hopper 14 is incremented by k+1.

[0128] In step S97, it is determined whether the number k of the supply hopper 14 is n+1, and if the number k is not n+1, the process returns to step S92.

[0129] FIG. 9 is a timing chart for single-shift operation.

[0130] Single shift operation is an operation in which combination processing is performed once during one weighing cycle. When the combination weigher has a large number of rows (heads), combination processing is performed r times during one operation cycle time (one weighing cycle time) while maintaining combination accuracy, allowing the weighed objects to be discharged r times, enabling high-speed discharge operation.

[0131] When r=1, the configuration is for so-called single shift operation, when r=2, the configuration is for so-called double shift operation, and when r=3, the configuration is for so-called triple shift operation.

[0132] Figure 9(a) is a waveform diagram of the item discharge request signal input from the packaging machine 2 to the control unit 1b of the combination weigher 1, Figure 9(b) is a waveform diagram of the combination calculation of the weighing hopper 15 in the control unit 1b of the combination weigher 1, Figure 9(c) is a waveform diagram of the weighing hopper open time indicating that the gate of the weighing hopper 15 is open, which is the time required from when the gate of the weighing hopper 15 starts to open until it starts to close, Figure 9(d) is a waveform diagram of the supply hopper open time indicating that the gate of the supply hopper 14 is open, which is the time required from when the gate of the supply hopper 14 starts to open until it starts to close, Figure 9(e) is a waveform diagram indicating the drive time of the straight feeder 13, and Figure 9(f) is a waveform diagram indicating the weighing stabilization time.

[0133] 9(f) is the time from when the items put into the weighing hopper 15 from the supply hopper 14 have passed the weighing stabilization time and the weighed value has become accurate, to when an item discharge request signal is input from the packaging machine 2 to the combination weigher 1 and combination calculation begins. The longer the weighing stabilization time, the more stable the weighed value becomes, so α should be set as short as possible.

[0134] where: Weighing The stabilization time is the time required for the weighing signal from the weighing sensor 16a to stabilize, and starts from the point when the supply hopper 14 starts to open. As shown in the flowchart in Figure 6, the weighing hopper 15 that has passed the weighing stabilization time can participate in the combination calculation as an active hopper.

[0135] FIG. 10 is a timing chart of double shift operation.

[0136] Double shift operation is an operation in which combination processing is performed twice during one weighing cycle. When the combination weigher has a large number of rows (heads), combination processing is performed r times during one operation cycle time (one weighing cycle time) while maintaining combination accuracy, allowing the weighed objects to be discharged r times, enabling high-speed discharge operation.

[0137] 10(a) is a waveform diagram of an article discharge request signal input from the packaging machine 2 to the control unit 1b of the combination weigher 1, FIG. 10(b) is a waveform diagram of the combination calculation of the weighing hopper 15 in the control unit 1b of the combination weigher 1, FIG. 10(c) is a waveform diagram of the gate open time of group 1 of the weighing hopper 15, FIG. 10(d) is a waveform diagram of the gate open time of group 2 of the weighing hopper 15, FIG. 10(e) is a waveform diagram of the weighing stabilization time of group 1 of the weighing hopper 15, FIG. 10(f) is a waveform diagram of the weighing stabilization time of group 2 of the weighing hopper 15, FIG. 10(g) is a waveform diagram of the supply hopper open time, which indicates the time required from when the gate of the supply hopper 14 starts to open until it starts to close, i.e., the time required for the gate of the supply hopper 14 to open, and FIG. 10(h) is a waveform diagram showing the drive time of the straight feeder 13. Here, the stabilization time is the time required for the weighing signal from the weighing sensor 16a to stabilize, and is calculated from the time when the supply hopper 14 starts to open.

[0138] The discharge gate of the weighing hopper is controlled by a pulse motor. The discharge gate opens and closes. The opening and closing times are separate. When the combination weigher has a large number of rows (number of heads), the combination process is carried out r times during one operation cycle time (one weighing cycle time) while maintaining combination accuracy, allowing items to be discharged r times, enabling high-speed discharge operations. When r=2, this is a configuration that performs so-called double shift operation, and when r=3, this is a configuration that performs so-called triple shift operation. [Explanation of symbols]

[0139] 1 Combination weigher 11 Level Sensor 12 Dispersion Feeder 13 Straight feeder 14 Supply hopper 15 Weighing hopper 17 Group Shootout 2 Packaging machine 3 Feeding device 4 Operation setting display device

Claims

1. a combination weigher that combines and measures the weight of articles and discharges them; a packaging machine that packages the items discharged from the combination weigher; Including, the packaging machine outputs an article discharge request signal to the combination weigher, indicating that preparation for packaging the articles discharged from the combination weigher has been completed and that the packaging machine requests the combination weigher to discharge the articles; the combination weigher has a plurality of weighing hoppers that temporarily store articles and measure the weight of the stored articles; In a weighing and packaging system, the combination weigher, in response to an input of the item discharge request signal from the packaging machine, combines and calculates weights of items stored in the plurality of weighing hoppers, selects a weighing hopper from the plurality of weighing hoppers that has a combination within a predetermined weight range, and outputs an item discharge signal to the packaging machine indicating that the items are to be discharged from the selected weighing hopper to the packaging machine, thereby discharging the items, A weighing and packaging system characterized in that the weighing stabilization time after the items are placed in the weighing hopper of the combination weigher is automatically determined and updated in accordance with the input period of the item discharge request signal from the packaging machine, without setting the operating speed of the combination weigher.

2. The weighing and packaging system of claim 1, characterized in that a minimum weighing stabilization time at which weighing accuracy can be maintained is set for the weighing stabilization time, and if the weighing stabilization time calculated using the input period multiplied by 1 is shorter than the minimum weighing stabilization time, the weighing stabilization time is calculated using the input period multiplied by 2.

3. 3. The weighing and packaging system according to claim 1, wherein if there is no weighing hopper for which a predetermined number of stable weighing times have elapsed, the combination calculation is not performed.

4. A weighing and packaging system according to any one of claims 1 to 3, wherein the cycle time is the average value of the time intervals for N detections of the item discharge request signal, and the weighing stabilization time is the value obtained by subtracting the gate open time of the weighing hopper from the cycle time.

5. A combination weigher used in the weighing and packaging system according to any one of claims 1 to 4.

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