Combination weighing device and method for controlling the combination weighing device

Abstract

To provide a combination weigher capable of improving productivity.SOLUTION: A combination weigher in an embodiment includes: conveyor 3; a combination processing unit 51 that finds the discharge combination including multiple weighing object holders and weighing object holder for the object to be weighed whose total weight is within the target weight range, in which the total weight of the objects to be weighed is within the target weight range; a timing derivation unit 52 that obtains start timing of an ejection operation of each weighing object holder so that the objects to be weighed discharged from each weighing object holder of the discharge combination are positioned at a same position on the transport conveyor 3; an operation control unit 53 that is configured to control the conveyor 3 to start a conveying operation and the weighing object holder to start the discharging operation based on the start timing each time a discharge request signal is input from the downstream device 50, and after starting conveyor 3, to control the conveyor 3 to terminate the conveying operation so that the objects to be weighed discharged from the weighing object holder stop at a conveying termination area of the conveyor 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a combination weigher that combines and discharges objects to be weighed whose total weight falls within a predetermined target weight range, and a method for controlling the combination weigher. [Background technology]

[0002] A combination scale is configured, for example, to weigh each of a number of objects to be weighed, perform a combination calculation using the weight values ​​of the weighed objects, and discharge objects whose total weight is within a predetermined target weight range.

[0003] Patent Documents 1 and 2 disclose a combination weighing scale that includes multiple weighing conveyors for weighing the objects to be weighed, multiple supply conveyors that supply the objects to each weighing conveyor, and one transport conveyor (collective conveyor) that transports the objects to be weighed discharged from each weighing conveyor and discharges them to a downstream device such as a packaging machine. In this combination weighing scale, after inputting a discharge request signal (discharge command signal) from the downstream device, the objects to be weighed whose total weight is within a target weight range are discharged from the multiple weighing conveyors to the transport conveyor, and the objects to be weighed are transported by the transport conveyor and discharged to the downstream device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-120121 A [Patent Document 2] JP 2013-120122 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the configurations of Patent Documents 1 and 2, the objects to be weighed must be discharged from multiple weighing conveyors and then transported by a transport conveyor after receiving a discharge request signal from the subsequent device and before the objects to be weighed are discharged to the subsequent device. Therefore, the time from receiving a discharge request signal to discharging the objects to the subsequent device is long, leaving room for improvement in terms of improving productivity (processing capacity).

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide a combination weigher and a control method for the combination weigher that can improve productivity. [Means for solving the problem]

[0007] In order to achieve the above object, a combination weigher according to one embodiment of the present invention comprises a transport conveyor that transports objects to be weighed in one direction and discharges them to a downstream device; a plurality of object holding sections that temporarily hold the objects to be weighed supplied and then discharge them from a discharge outlet, thereby supplying the objects to the transport conveyor, with each of the discharge outlets being arranged at a respective predetermined position with respect to the transport direction of the transport conveyor; a combination processing unit that repeatedly performs a combination process to find one discharge combination consisting of a combination of the object holding sections that the total weight of the objects held falls within a target weight range; and each time a discharge combination is found by the combination process, a combination processing unit that repeatedly performs a combination process to find one discharge combination consisting of a combination of the object holding sections that the object holding sections selected for the discharge combination have based on the position of the discharge outlet of the object holding sections selected for the discharge combination and the transport speed of the transport conveyor. The system is equipped with a timing derivation unit that determines the start timing of the discharge operation of each of the weighed object holding units so that the weighed objects discharged from each of the weighed object holding units selected for the discharge combination are positioned at the same position on the conveying conveyor, and an operation control unit that causes the conveying conveyor to start a conveying operation and causes the weighed object holding units to start a discharge operation based on the start timing determined by the timing derivation unit each time a discharge request signal is input from the downstream device, and further causes the conveying conveyor to end its conveying operation after starting its conveying operation and transporting the weighed objects discharged from the weighed object holding units so that the weighed objects stop at the conveying terminal area of ​​the conveying conveyor.

[0008] According to this configuration, the objects to be weighed discharged from each of the weighed object holding sections selected for the discharge combination are transported so as to be positioned (concentrated) at the same position on the transport conveyor, and are stopped in a concentrated state at the transport end area of ​​the transport conveyor. As a result, when a discharge request signal is input from the subsequent device, the objects to be weighed can be immediately discharged to the subsequent device, and the objects to be weighed can be discharged in a concentrated state. Therefore, the time from input of a discharge request signal from the subsequent device to the discharge of the objects to be weighed to the subsequent device can be shortened, and productivity can be improved.

[0009] In this specification and claims, the term "transport end area of ​​the transport conveyor" refers to a predetermined transport end of the transport conveyor and a predetermined area in the vicinity thereof.

[0010] The timing derivation unit may be configured to determine, each time a discharge combination is determined by the combination process, an end timing of the conveying operation of the conveying conveyor based on the position of the discharge outlet of the weighed object holding unit that is located furthest upstream in the conveying direction of the conveying conveyor among the weighed object holding units selected for the discharge combination, so that the weighed objects discharged from the weighed object holding units and conveyed by the conveying conveyor stop at the conveying terminal area of ​​the conveying conveyor, and the operation control unit may be configured to cause the conveying conveyor to start its conveying operation, and then cause the conveying conveyor to end its conveying operation based on the end timing determined by the timing derivation unit.

[0011] The conveyor may further include a weighed object detection unit that detects weighed objects present in the conveying terminal area of ​​the conveying conveyor, and the operation control unit may be configured to cause the conveying conveyor to terminate its conveying operation when a new weighed object is detected by the weighed object detection unit while the conveying conveyor is performing its conveying operation.

[0012] The apparatus may further include a collecting hopper that receives the objects to be weighed discharged from the discharge end of the transport conveyor, temporarily holds them, and then discharges them to the downstream device, and the operation control unit may be configured to immediately discharge the objects to be weighed from the collecting hopper when it receives a discharge request signal from the downstream device.

[0013] According to this configuration, the objects to be weighed are discharged from the collecting hopper in a more consolidated state, which makes it easier to coordinate operations with the subsequent device. In this case, when the operation control unit receives a discharge request signal from the subsequent device, it can immediately discharge the objects to be weighed in a consolidated state from the collecting hopper to the subsequent device, thereby shortening the discharge time (the time required to supply the objects to the subsequent device) and further improving productivity.

[0014] The discharge end of the conveyor may further be provided with a path opening / closing section which switches between closing and opening the discharge path of the objects to be weighed, and the path opening / closing section may be configured to open the discharge path to allow the objects to be weighed to be discharged from the conveyor during a period from the start of the conveying operation of the conveyor until a predetermined time has elapsed, and to close the discharge path to prevent the objects to be weighed from the conveyor during other than the said period.

[0015] By providing such a path opening / closing section, even if the object to be weighed is an item that tends to roll, it is possible to prevent the object to be weighed from falling from the discharge end of the conveyor when the conveying operation of the conveyor is terminated (stopped), and the object to be weighed can be reliably stopped in the conveying terminal area of ​​the conveyor.

[0016] The weighed object holding section may be configured as a weighing conveyor which receives the weighed object when the conveying is stopped, temporarily holds and weighs the weighed object, and conveys it for a predetermined period of time, thereby discharging the held weighed object onto the conveying conveyor.

[0017] A control method for a combination weigher according to an embodiment of the present invention is a control method for a combination weigher including a transport conveyor that transports objects to be weighed in one direction and discharges them to a subsequent device, and a plurality of object holding sections that temporarily hold the objects to be weighed supplied and then discharge them from a discharge outlet, thereby supplying the objects to the transport conveyor, and each of the discharge outlets is arranged at a predetermined position relative to the transport direction of the transport conveyor, the control method comprising: repeatedly performing a combination process to find one discharge combination consisting of a combination of the object holding sections such that the total weight of the objects held by them falls within a target weight range, and each time a discharge combination is found by the combination process, a combination process is performed based on the position of the discharge outlet of the object holding section selected for the discharge combination and the transport speed of the transport conveyor. A timing derivation process is performed to determine the start timing of the discharge operation of each of the weighed object holding sections so that the weighed objects discharged from each of the weighed object holding sections selected for the discharge combination are positioned at the same position on the conveying conveyor, and each time a discharge request signal is input from the downstream device, the conveying conveyor is caused to start a conveying operation and the weighed object holding section is caused to start a discharge operation based on the start timing determined by the timing derivation process, and after the conveying conveyor has started its conveying operation, an operation control process is performed to convey the weighed objects discharged from the weighed object holding sections and have the conveying conveyor terminate its conveying operation so that the weighed objects stop at the conveying terminal area of ​​the conveying conveyor.

[0018] According to this control method, the objects to be weighed discharged from each of the object holding sections selected for the discharge combination are transported so as to be positioned at the same position (concentrated) on the transport conveyor, and are stopped in a concentrated state at the transport end area of ​​the transport conveyor. As a result, when a discharge request signal is input from the subsequent device, the objects to be weighed can be immediately discharged to the subsequent device, and the objects to be weighed can be discharged in a concentrated state. Therefore, the time from input of a discharge request signal from the subsequent device to the discharge of the objects to be weighed to the subsequent device can be shortened, and productivity can be improved. Effect of the Invention

[0019] The present invention has the above-described configuration and has an effect of providing a combination weigher and a control method for a combination weigher that can improve productivity. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1(A) is a schematic plan view of a combination weigher according to an example of this embodiment, viewed from above, and FIG. 1(B) is a schematic view showing the main parts of the same combination weigher, viewed from the side. [Diagram 2] FIG. 2 is a block diagram showing a schematic configuration of the combination weigher shown in FIG. [Diagram 3] FIG. 3 is a schematic diagram showing the arrangement of the weighing conveyors and the transport conveyors used to explain the operation of the combination weigher shown in FIG. [Figure 4] FIG. 4 is a flowchart showing an example of the operation of the combination weigher shown in FIG. [Diagram 5] FIG. 5 is a diagram showing a main part of a modified example of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout the drawings, and duplicated descriptions thereof will be omitted. Furthermore, the present invention is not limited to the following embodiments. Furthermore, the numerical values ​​exemplified below are merely examples, and the present invention is not limited to these numerical values.

[0022] (Embodiment) Fig. 1(A) is a schematic plan view of a combination weigher according to an example of the present embodiment as viewed from above, and Fig. 1(B) is a schematic view showing the main parts (weighing unit and transport conveyor) of the combination weigher as viewed from the side. Also, Fig. 2 is a block diagram showing the schematic configuration of the combination weigher shown in Fig. 1.

[0023] This combination weigher includes a plurality of (for example, 12) weighing sections Cw, a transport conveyor 3, an operation display device 4, a control device 5, and the like.

[0024] The transport conveyor 3 is disposed approximately in the center, and six weighing units Cw are disposed on each side of the transport conveyor 3. In this example, each weighing unit Cw is composed of a weighing conveyor 1 made of a belt conveyor supported by a weight sensor 2 such as a load cell. Here, the group consisting of six weighing units Cw on one side of the transport conveyor 3 will be described as weighing group G1, and the group consisting of six weighing units Cw on the other side will be described as weighing group G2.

[0025] The six weighing conveyors 1 of the weighing section Cw of the weighing group G1 are arranged in parallel on one side of the transport conveyor 3, and are arranged so that their respective transport directions (the direction of arrow a) intersect (in this example, perpendicular) with the transport direction (the direction of arrow c) of the transport conveyor 3. The six weighing conveyors 1 of the weighing section Cw of the weighing group G2 are arranged in parallel on the other side of the transport conveyor 3, and are arranged so that their respective transport directions (the direction of arrow b) intersect (in this example, perpendicular) with the transport direction of the transport conveyor 3.

[0026] The transport conveyor 3 is composed of a belt conveyor, and transports the objects to be weighed discharged from each weighing conveyor 1, for example in the direction of the arrow c. The objects to be weighed transported by the transport conveyor 3 are supplied to the subsequent stage device 50, which is installed at the next stage of the combination weigher. In the example of Fig. 1, a funnel 21 is provided near the discharge end 3a of the transport conveyor 3, and the objects to be weighed discharged from the transport conveyor 3 pass through a lower exit 21a of the funnel 21 and are supplied to the subsequent stage device 50.

[0027] Each of the weighing conveyors 1 and the transport conveyor 3 may be provided with a pair of guide plates (not shown) on both sides to prevent the objects to be weighed from falling off the sides.

[0028] In addition, the device main body 15 is mounted on a stand (not shown), and the weighing conveyor 1, the transport conveyor 3, etc. are mounted on the device main body 15. In addition, the device main body 15 houses the conveyor drive circuit sections 8a and 8b, the A / D conversion section 9, the control device 5, the I / O circuit section 12, etc. shown in Fig. 2.

[0029] In each weighing section Cw, the weight of the object on the weighing conveyor 1 is measured by the weight sensor 2, and the measured value (analog weight signal) is converted into a digital signal by the A / D conversion section 9 and sent to the control device 5.

[0030] The control device 5 is configured, for example, by a microcontroller, and has an arithmetic control unit 6 consisting of a CPU, etc., and a storage unit 7 consisting of memories such as RAM and ROM. The storage unit 7 stores operation programs, operation parameter data, measurement data, etc. The control device 5 has a timer function, and functions as a combination processing unit 51, a timing derivation unit 52, an operation control unit 53, etc. The control device 5 may be configured by a single control device that performs centralized control, or may be configured by a plurality of control devices that cooperate with each other to perform distributed control.

[0031] The control device 5 controls the entire combination weigher and performs combination processing, etc., as described below, by executing an operation program stored in the storage unit 7 by the calculation control unit 6. For example, the weighing values ​​measured by each weight sensor 2 are acquired as digital values ​​via the A / D conversion unit 9 at any time, and stored in the storage unit 7 if necessary. The control device 5 also controls the conveying operation of each weighing conveyor 1 and the conveying conveyor 3 via the conveyor driving circuits 8a and 8b. The control device 5 can also send and receive signals to and from the subsequent device 50 via the I / O circuit unit 12. In this example, the control device 5 receives a discharge request signal from the subsequent device 50 and outputs a discharge notification signal to the subsequent device 50. The control device 5 also receives a signal from the operation display unit 4 and outputs a signal such as data to be displayed on the operation display unit 4. The A / D conversion unit 9 and the I / O circuit unit 12 may be included in the control device 5.

[0032] The operation display unit 4 is equipped with, for example, a touch screen display (display device), and on the screen of this display, operations such as starting and stopping the operation of the combination weigher and setting operating parameters can be performed, and the results of the combination processing by the control device 5 (combined weight, etc.) can be displayed on the display screen.

[0033] The latter-stage device 50 outputs a discharge request signal to the combination weigher (control device 5) when it is ready to accept the objects to be weighed, or at a predetermined timing immediately before that. Also, when a discharge notification signal is input from the combination weigher (control device 5), it is configured to start a predetermined operation based on the input timing. For example, a bag-feeding packaging machine for bagging the objects to be weighed may be disposed as the latter-stage device 50. Also, for example, a tray conveying device that connects multiple trays (shallow boxes) in a ring shape and moves them horizontally intermittently may be disposed as the latter-stage device 50.

[0034] 1(A) is provided so that the objects to be weighed discharged from the discharge end 3a of the transport conveyor 3 are accurately placed into a bag (in the case of a packaging machine) or a tray (in the case of a tray transport device) of the subsequent device 50. The objects to be weighed discharged from the transport conveyor 3 pass through the lower exit 21a of the funnel 21 and are placed into a bag or tray.

[0035] Next, an example of the operation of the combination weigher of this embodiment will be described. In this embodiment, an operator performs the task of supplying (placing) objects to be weighed to a weighing conveyor 1 that is stopped and has no objects on it at any time. Here, the objects to be weighed supplied to each weighing conveyor 1 at one time may consist of one item or may consist of multiple items. The objects to be weighed are, for example, agricultural products or marine products.

[0036] The control device 5 acquires the weighing values ​​of each weight sensor 2 at regular time intervals from the A / D conversion unit 9, and recognizes the weighing conveyor 1 to which the objects to be weighed are being supplied based on the weighing values ​​of the weight sensors 2, and recognizes the weight values ​​of the objects to be weighed. When recognizing the weighing conveyor 1 to which the objects to be weighed are being supplied, the control device 5 compares the weighing value (weight value) with a preset load detection reference value (e.g., 6 g), and if the weighing value is equal to or greater than the load detection reference value, it determines that the objects to be weighed are being supplied, and if the weighing value is less than the load detection reference value, it determines that the objects to be weighed are not being supplied.

[0037] Here, the combination process by the control device 5 (combination processing unit 51) will be described. In this combination process, a combination calculation is performed based on the weight of the objects to be weighed on each weighing conveyor 1 obtained from the measurement value of each weight sensor 2, and all combinations of the weighing conveyors 1 in which the total weight (combined weight) of the objects to be weighed being supplied falls within a predetermined target weight range (tolerance range for the target weight) are found, and one combination is determined as the discharge combination. Here, if there are multiple combinations that fall within the target weight range, for example, the combination in which the absolute value of the difference between the combined weight and the target weight is the smallest among the multiple combinations is determined as the discharge combination. Note that, although details will be described later, the objects to be weighed on the weighing conveyor 1 selected as the discharge combination by the combination process are transported by the weighing conveyor 1 and discharged from its discharge end 1a onto the transport conveyor 3. In this embodiment, each weighing conveyor 1 is a weighing object holding unit, and its discharge end 1a is a discharge outlet of the weighing object holding unit.

[0038] FIG. 3 is a schematic diagram showing the arrangement of the weighing conveyor 1 and the transport conveyor 3, which is used to explain the operation of the combination weigher shown in FIG.

[0039] In this embodiment, it is assumed that the position where the worker places the objects to be weighed on each weighing conveyor 1 is specified in the operation manual or the like, for example, at the center position in the longitudinal direction of the weighing conveyor 1. The conveying speed of all weighing conveyors 1 is set to be the same, and it is assumed that the time required from the start of the conveying operation of each weighing conveyor 1 until the objects to be weighed on that weighing conveyor 1 are discharged onto the conveying conveyor 3 is the same. Therefore, the relationship between the discharge timing at which the objects to be weighed are discharged from the discharge end 1a of each weighing conveyor 1 to the conveying conveyor 3 (the discharge order and discharge time interval of each weighing conveyor 1) and the relationship between the start timing of the conveying operation of each weighing conveyor 1 (the start order of the conveying operation of each weighing conveyor 1 and the start time interval of the conveying operation) are equal.

[0040] 3, a conveyor number is assigned to each weighing conveyor 1 in order from the one closest to the discharge end 3a of the transport conveyor 3, and the conveyor number for each weighing conveyor 1 is stored in the memory unit 7. Note that, for weighing conveyors 1 that are located at the same position in the transport direction of the transport conveyor 3 and are arranged opposite each other with the transport conveyor 3 in between, a smaller conveyor number is assigned to one of them and the next conveyor number is assigned to the other. Also, the center-to-center distance between adjacent weighing conveyors 1 in the machine length direction (transport direction) of the transport conveyor 3 is defined as L, and the distance from the discharge end 3a of the transport conveyor 3 to the center of the weighing conveyor 1 closest to this discharge end 3a is defined as P.

[0041] In addition, in FIG. 3, the objects to be weighed discharged from the weighing conveyor 1 with the conveyor number (k) are indicated as Mk (k=1 to 12). For example, M12 is an object to be weighed discharged from the weighing conveyor 1 with the conveyor number (12). In addition, the "conveying position" in FIG. 3 indicates the position of the discharge end 1a (center position of the discharge end 1a), which is the discharge port of the weighing conveyor 1, in the conveying direction of the conveying conveyor 3. In FIG. 3, the positions of the discharge ends 1a of the weighing conveyors 1 with the conveyor numbers (1) and (2) are set to 0, and the "conveying positions" are illustrated so that the position value increases toward the upstream side of the conveying conveyor 3, but this is not limiting. The control device 5 stores the "conveying positions" of each weighing conveyor 1 in the memory unit 7 in advance.

[0042] In this embodiment, in order to ensure that the objects to be weighed discharged from each weighing conveyor 1 selected in the discharge combination are transported at the same position on the transport conveyor 3, the control device 5 determines the start timing of the transport operation of each weighing conveyor 1 selected in the discharge combination, and causes each weighing conveyor 1 to start the transport operation based on the start timing. Therefore, among the multiple weighing conveyors 1 selected in the discharge combination, the objects to be weighed are discharged in order from the weighing conveyor 1 closest to the upstream end 3b of the transport conveyor 3 in the transport direction.

[0043] 3, for example, four weighing conveyors 1 with conveyor numbers (3), (4), (7), and (12) are selected as the discharge combination, and the state of transport of the objects to be weighed M3, M4, M7, and M12 discharged from these weighing conveyors 1 on the transport conveyor 3 is shown. In this case, when the transport conveyor 3 starts to transport, first, the object to be weighed M12 is discharged from the weighing conveyor 1 with conveyor number (12), and then this object to be weighed M12 is transported by the transport conveyor 3, and when this object to be weighed M12 passes in front of the weighing conveyor 1 with conveyor number (7), the object to be weighed M7 is discharged from this weighing conveyor 1. Then, the two objects to be weighed M7 and M12 are transported together by the transport conveyor 3, and when they pass in front of the weighing conveyors 1 with conveyor numbers (3) and (4), the objects to be weighed M3 and M4 are discharged from the two weighing conveyors 1. Then, the four objects to be weighed M3, M4, M7, and M12 are conveyed together by the conveyor 3, and the conveyor 3 is caused to terminate (stop) its conveying operation so that the objects stop in the conveying end region R of the conveyor 3.

[0044] The conveyance end region R of the conveyor 3 refers to the conveyance end (discharge end 3a) of the conveyor 3 and a predetermined region in the vicinity thereof, and may be, for example, as shown in Fig. 3, a region from the discharge end 3a of the conveyor 3 to a position on the conveyor 3 corresponding to the center position of the discharge end 1a of the weighing conveyor 1 that is closest to the discharge end 3a of the conveyor 3 (a region corresponding to the distance P). The conveyance end region R shown in the figure indicates a region when it is the maximum region, and may be a predetermined region on the discharge end 3a side of the center position of the discharge end 1a of the weighing conveyor 1 that is closest to the discharge end 3a.

[0045] Here, the timing at which the conveying operations of the multiple weighing conveyors 1 selected in the discharge combination start will be described.

[0046] In this embodiment, in order to position the weighed objects discharged from each weighing conveyor 1 at the same position on the transport conveyor 3, the transport operation is started in order from the weighing conveyor 1 closest to the upstream end 3b of the transport conveyor 3.

[0047] Therefore, for example, as shown in FIG. 3, when four weighing conveyors 1 with conveyor numbers (3), (4), (7), and (12) are selected as a discharge combination, the control device 5 (timing derivation unit 52) ​​calculates a delay time D1 of the start time of the conveying operation of the weighing conveyor 1 with conveyor number (7) and a delay time D2 of the start time of the conveying operation of the weighing conveyors 1 with conveyor numbers (3) and (4) relative to the start time of the conveying operation of the weighing conveyor 1 with conveyor number (12), which will start the conveying operation first.

[0048] Here, the delay time D1 of the weighing conveyor 1 with conveyor number (7) can be calculated based on the center-to-center distance (2×L) between the discharge ends 1a of the weighing conveyors 1 with conveyor numbers (12) and (7) and the conveying speed Vt of the transport conveyor 3. Here, the center-to-center distance (2×L) between the discharge ends 1a of the weighing conveyors 1 with conveyor numbers (12) and (7) can be calculated as the difference between 5L, which is the "conveying position" of the discharge end 1a of the weighing conveyor 1 with conveyor number (12), and 3L, which is the "conveying position" of the discharge end 1a of the weighing conveyor 1 with conveyor number (7). In other words, the delay time D1 can be calculated by the following formula.

[0049] D1=(5L-3L) / Vt In addition, the delay time D2 of the weighing conveyors 1 with conveyor numbers (3) and (4) can be calculated based on the center-to-center distance (4×L) between the discharge ends 1a of the weighing conveyors 1 with conveyor numbers (12) and (3), and (4) and the conveying speed Vt of the conveying conveyor 3. Here, the center-to-center distance (4×L) between the discharge ends 1a of the weighing conveyors 1 with conveyor numbers (12) and (3), and (4) can be calculated as the difference between 5L, which is the "conveying position" of the discharge end 1a of the weighing conveyor 1 with conveyor number (12), and L, which is the "conveying position" of the discharge ends 1a of the weighing conveyors 1 with conveyor numbers (3) and (4). In other words, the delay time D2 can be calculated by the following formula.

[0050] D2=(5L-L) / Vt In addition, when the four weighing conveyors 1 with the above conveyor numbers (3), (4), (7), and (12) are the discharge combination determined in the first combination process since the combination scale started operating, there are no objects to be weighed in the transport terminal area R of the transport conveyor 3. Therefore, when the above discharge combination is determined, the weighing conveyor 1 with the conveyor number (12) may be made to immediately start transport operation.

[0051] As described above, the control device 5 (timing derivation unit 52) ​​determines that, among the weighing conveyors 1 selected for the discharge combination, the weighing conveyor 1 (there may be two) that is closest to the upstream end 3b of the transport conveyor 3 is the first to start its transport operation, and calculates the delay time (the aforementioned D1, D2, etc.) for the start time (start timing) of the transport operation of the other weighing conveyors 1 relative to the start time (start timing) of the transport operation of the weighing conveyor 1 that is to start its transport operation first, thereby determining the start timing of the transport operation (discharge operation of the weighed object holding section) of each weighing conveyor 1 selected for the discharge combination.

[0052] Next, the start and end timings of the transport operation of the transport conveyor 3 will be described.

[0053] When the control device 5 (operation control section 53) receives a discharge request signal from the subsequent device 50, it immediately causes the transport conveyor 3 to start a conveying operation. Immediately thereafter, or at the same time, the control device 5 causes the weighing conveyor 1 selected for the discharge combination to start a conveying operation first to start a conveying operation, and then at an appropriate time causes the weighing conveyors 1 selected for the same discharge combination to start a conveying operation. In the above example, the control device 5 causes the weighing conveyor 1 with conveyor number (12) to start a conveying operation first, and then causes the weighing conveyor 1 with conveyor number (7) to start a conveying operation after a delay time D1, and causes the weighing conveyors 1 with conveyor numbers (3) and (4) to start a conveying operation after a delay time D2.

[0054] In this embodiment, the control device 5 (operation control unit 53) causes the conveying conveyor 3 to terminate (stop) its conveying operation so that the objects to be weighed discharged from the multiple weighing conveyors 1 selected for the discharge combination are conveyed by the conveying conveyor 3 and stopped at the conveying terminal area R of the conveying conveyor 3.

[0055] Therefore, the control device 5 (timing derivation unit 52) ​​determines the end timing of the conveying operation of the conveying conveyor 3, for example, by calculating the delay time De of the end time of the conveying operation of the conveying conveyor 3 relative to the start time of the conveying operation of the weighing conveyor 1, which starts the conveying operation first, using the following formula.

[0056] De=t1+t2 In the above formula, t1 is a predetermined time that is determined in advance as the time required for each weighing conveyor 1 to discharge the objects to be weighed from the start of the conveying operation to the discharge onto the transport conveyor 3, and is stored in the storage unit 7 in advance.

[0057] Furthermore, t2 is the time taken for the object to be weighed (its center) discharged from the weighing conveyor 1 that first starts its conveying operation to be conveyed on the conveying conveyor 3 until it reaches a predetermined position X1 in the conveying terminal area R on the conveying conveyor 3. This time t2 can be calculated based on the distance (Lx) from the center position of the discharge end 1a of the weighing conveyor 1 that first starts its conveying operation to the predetermined position X1 in the conveying terminal area R, and the conveying speed Vt of the conveying conveyor 3, as t2=Lx / Vt.

[0058] Here, the predetermined position X1 is a position that is a predetermined distance P1 away from the center position of the discharge end 1a of the weighing conveyors 1 with conveyor numbers (1) and (2) toward the discharge end 3a of the transport conveyor 3. For example, when the weighing conveyor 1 with conveyor number (12) is to start a transport operation first, the distance Lx to the predetermined position X1 can be calculated as 5L+P1 using 5L, which is the "transport position" of the weighing conveyor 1. In this case, the predetermined distance P1 is stored in the storage unit 7 in advance. The distance Lx may also be stored in the storage unit 7 in advance in association with the conveyor number of each weighing conveyor 1.

[0059] As described above, by ending the conveying operation of the conveying conveyor 3 after the delay time De from the start time of the conveying operation of the weighing conveyor 1, which first starts the conveying operation, the center of the object to be weighed being conveyed on the conveying conveyor 3 stops at a predetermined position X1, and the center of this stopped object to be weighed is located within the conveying terminal area R of the conveying conveyor 3.

[0060] In addition, if the start time of the conveying operation of the weighing conveyor 1, which is the first to start its conveying operation, is set to be the same as the start time of the conveying operation of the conveying conveyor 3, in other words, when a discharge request signal is input from the downstream device 50, the conveying conveyor 3 is immediately caused to start its conveying operation and at the same time the weighing conveyor 1, which is the first to start its conveying operation, is caused to start its conveying operation, then the above-mentioned delay time De becomes the conveying operation time (conveying time) of the conveying conveyor 3.

[0061] Figure 4 is a flowchart showing an example of the operation of the combination weigher shown in Figure 1. The operation of this combination weigher is realized by the processing of the control device 5. All information required to control the operation of the combination weigher is stored in the storage unit 7.

[0062] In step S1, the control device 5 determines whether or not a predetermined condition (execution condition) for executing the combination process is satisfied, and if the condition is satisfied, the control device 5 proceeds to step S2 to execute the combination process described above and obtain one discharge combination. Note that the execution condition for the combination process in step S1 is, for example, that a predetermined number (e.g., seven) of objects to be weighed have been supplied to the weighing conveyor 1 and their weights have been measured.

[0063] Next, in step S3, the control device 5 calculates the start timing of the conveying operation of each weighing conveyor 1 selected in the discharge combination (e.g., the aforementioned delay time D1, D2), and in step S4, calculates the end timing of the conveying operation of the conveying conveyor 3 (e.g., the aforementioned delay time De).

[0064] Next, in step S5, the control device 5 determines whether or not a discharge request signal has been input from the downstream device 50, and if not, the process returns to step S1, and if a discharge request signal has been input, the process proceeds to step S6. Here, when returning to step S1, if the discharge combination determined in step S2 this time (the time when the process has returned) is different from the discharge combination determined in step S2 the previous time, the discharge combination is updated to the discharge combination determined in step S2 this time, and the results of steps S3 and S4 calculated based on this are also updated.

[0065] Then, when the control device 5 receives a discharge request signal from the subsequent device 50, in step S6, it causes the transport conveyor 3 to start a transport operation, and in step S7, it causes each weighing conveyor 1 selected in the discharge combination to operate for a predetermined transport time based on the start timing of the transport operation of each weighing conveyor 1 selected in the discharge combination. This predetermined transport time is a time for operating the weighing conveyor 1 to discharge the objects to be weighed on the weighing conveyor 1 to the transport conveyor 3, which is determined in advance.

[0066] Next, in step S8, the control device 5 causes the transport conveyor 3 to end the transport operation based on the end timing of the transport operation of the transport conveyor 3 calculated in step S4.

[0067] When the conveying operation of the conveyor 3 is started in step S6, the objects to be weighed on the weighing conveyor 1 selected for the previous discharge combination that was stopped in the conveying terminal area R of the conveyor 3 are supplied to the subsequent device 50 from the discharge end 3a of the conveyor 3 via the funnel 21. Although not shown in FIG. 4, the control device 5 outputs a discharge notification signal to the subsequent device 50 when a predetermined time has elapsed since the conveyor 3 was caused to start its conveying operation in step S6. The predetermined time here is a time that is predetermined as the time required from the start of the conveying operation of the conveyor 3 until the objects to be weighed that were stopped in the conveying terminal area R of the conveyor 3 are discharged from the discharge end 3a.

[0068] The above operations are repeated. The order of steps S3 and S4 may be reversed. Steps S3 and S4 may also be performed between steps S5 and S6.

[0069] In this embodiment, the objects to be weighed discharged from each weighing conveyor 1 selected in the discharge combination are transported so as to be positioned (concentrated) at the same position on the transport conveyor 3, and are stopped in a concentrated state in the transport terminal area R of the transport conveyor 3. This allows the objects to be immediately discharged to the subsequent stage device 50 when a discharge request signal is input from the subsequent stage device 50, and allows the objects to be discharged in a concentrated state. This makes it possible to shorten the time from input of a discharge request signal from the subsequent stage device 50 to discharge of the objects to be weighed to the subsequent stage device 50, thereby improving productivity.

[0070] (Modification) FIG. 5 is a diagram showing a main part of a modified example of this embodiment.

[0071] 5, in this embodiment, a collecting hopper 31 may be provided instead of the funnel 21. This collecting hopper 31 has a discharge gate 31g, and can accommodate and temporarily hold the objects M to be weighed discharged from the discharge end 3a of the transport conveyor 3, and then open the discharge gate 31g to discharge the objects M downward to the subsequent device 50. The operation of the collecting hopper 31 (opening and closing operation of the discharge gate 31g) is controlled by the control device 5.

[0072] When such a collecting hopper 31 is provided, the objects to be weighed discharged from the weighing conveyors 1 selected for the discharge combination determined the kth time (k is a positive integer) after the operation of the combination weigher is started can be held in the collecting hopper 31, while the objects to be weighed discharged from the weighing conveyors 1 selected for the next (k+1)th discharge combination can be held in the transport terminal area R of the transport conveyor 3. In this case, when the control device 5 receives a discharge request signal from the subsequent device 50, it immediately opens and closes (opens and closes) the discharge gate 31g, thereby discharging the objects to be weighed from the collecting hopper 31 and outputting a discharge notification signal to the subsequent device 50. In this case, when the control device 5 receives a discharge request signal from the downstream device 50, it immediately opens and closes the discharge gate 31g to discharge the objects to be weighed held in the collecting hopper 31. At this time, the control device 5 may be configured to cause the conveying conveyor 3 to start a conveying operation just before, simultaneously with, or just after the discharge gate 31g is closed so that the objects to be weighed held in the conveying terminal area R of the conveying conveyor 3 can be stored in the collecting hopper 31.

[0073] By providing the collecting hopper 31 in this manner, the objects to be weighed are discharged from the collecting hopper 31 in a more consolidated state, which makes it easier to coordinate operations with the subsequent stage device 50. In this case, when the control device 5 inputs a discharge request signal from the subsequent stage device 50, it can instantly discharge the objects to be weighed in a consolidated state from the collecting hopper 31 to the subsequent stage device 50, which shortens the discharge time (the time required to supply the objects to the subsequent stage device 50) and further improves productivity.

[0074] 5, in this embodiment, a path opening / closing unit 41 for switching between closing and opening the discharge path of the objects to be weighed M may be provided at the discharge end 3a of the conveyor 3. The operation of this path opening / closing unit 41 is controlled by the control device 5. This path opening / closing unit 41 is configured to open the discharge path of the objects to be weighed M to enable discharge of the objects to be weighed M from the conveyor 3 during a period from the start of the conveying operation of the conveyor 3 until a predetermined time (ta) has elapsed (referred to as period Ta), and to close the discharge path of the objects to be weighed M to prevent discharge of the objects to be weighed M from the discharge end 3a of the conveyor 3 during periods other than this period Ta. The predetermined time (ta) is preset as the time required for all of the objects to be weighed present in the conveying terminal region R to be discharged from the discharge end 3a of the conveyor 3 after the conveyor 3 starts its conveying operation.

[0075] The path opening / closing unit 41 may, for example, include a vertical plate 41a formed by placing a flat plate vertically and a drive device (not shown) for moving the vertical plate 41a up and down, and may close the discharge path for the objects to be weighed on the transport conveyor 3 by lowering the vertical plate 41a to a predetermined lowered position, and open the discharge path for the objects to be weighed M on the transport conveyor 3 by raising the vertical plate 41a to a predetermined raised position. The path opening / closing unit 41 may, for example, include double doors and a drive device for opening and closing the doors.

[0076] By providing such a path opening / closing section 41, even if the object to be weighed is an item that tends to roll, it is possible to prevent the object to be weighed from falling from the discharge end 3a of the conveying conveyor 3 when the conveying operation of the conveying conveyor 3 is terminated (stopped), and the object to be weighed can be reliably stopped in the conveying terminal area R.

[0077] In the above example, the control device 5 calculates the end timing of the conveying operation by the conveyor 3 (for example, the above-mentioned delay time De) and causes the conveyor 3 to end the conveying operation based on the calculated timing. Alternatively, as shown in FIG. 5, an object detection unit 11 may be provided for detecting the object M to be weighed that has reached the conveying end region R of the conveyor 3. The object detection unit 11 is configured using, for example, a photoelectric sensor, and outputs an object detection signal when it detects the object M to be weighed. This object detection signal is input to the control device 5. In this case, after the control device 5 causes the conveyor 3 to start the conveying operation, it causes the conveyor 3 to end the conveying operation when the object detection unit 11 detects a new object to be weighed. Note that the object detection unit 11 may be any device capable of detecting the object to be weighed, and may be, in addition to a photoelectric sensor, for example, an ultrasonic sensor, a capacitance type proximity sensor, or a camera and an image processing device.

[0078] In this embodiment, the weighing units Cw are arranged on both sides of the transport conveyor 3, but the weighing units Cw may be arranged only on one side of the transport conveyor 3. In this embodiment, a flat belt conveyor with a flat transport surface is used as the transport conveyor 3, but instead of this, a trough-type belt conveyor with a recessed central portion of the transport surface may be used. In addition, the transport conveyor 3 may be two belt conveyors having endless flat belts arranged in parallel so that the transport surfaces have a V-shaped cross section.

[0079] In addition, in this embodiment, belt conveyors are used for the weighing conveyor 1 and the transport conveyor 3, but roller conveyors or the like may be used depending on the type of objects to be weighed.

[0080] Furthermore, in this embodiment, the objects to be weighed are manually supplied to the weighing conveyor 1 by an operator. However, the objects may be automatically supplied to the weighing conveyor 1 by a supplying device such as a separately provided conveyor.

[0081] Furthermore, in this embodiment, the objects to be weighed are discharged directly from each weighing conveyor 1 to the transport conveyor 3, but it is also possible to provide another conveyor (hereinafter referred to as a "standby conveyor") between each weighing conveyor 1 and the transport conveyor 3, transport the objects to be weighed on each weighing conveyor 1 to each standby conveyor, perform a combination process based on the weight of the objects to be weighed held on the standby conveyor, and discharge the objects to be weighed from the standby conveyor selected for the discharge combination to the transport conveyor 3. Here, the weight of the objects to be weighed held on the standby conveyor is the weight measured when they were held on the weighing conveyor 1. In this case, the standby conveyor serves as the object holding section.

[0082] In this embodiment, the weighing conveyor 1 is used as the weighed object holding section, but instead of this, a configuration may be used in which a hopper to which the weighed objects are supplied from above is used. For example, instead of a plurality of weighing conveyors 1, a configuration may be used in which a plurality of hoppers are arranged in one or two straight rows in the conveying direction (direction of arrow c) above the transport conveyor 3, each arranged at a predetermined position. In this case, one combination of hoppers (discharge combination) in which the total weight of the supplied weighed objects falls within the target weight range is obtained, the weighed objects are discharged from the hopper selected for that discharge combination, and the discharged weighed objects are transported by the transport conveyor 3. The hopper has a discharge gate, temporarily holds the weighed objects supplied from above, and discharges the weighed objects by opening and closing the discharge gate, which serves as a discharge outlet.

[0083] In this case, the start timing of the discharge operation of the hopper, ie, the start timing of the opening and closing operation of the discharge gate of the hopper, can be obtained in the same manner as in the case of obtaining the start timing of the transport operation of the weighing conveyor 1.

[0084] In addition, the hopper is supported by a weight sensor so that the weight of the objects to be weighed can be measured, and the objects to be weighed may be supplied to the hopper automatically or manually by an operator.

[0085] Also, a second hopper for supplying the objects to be weighed to the hopper may be provided above the hopper, and the second hopper may be supported by a weight sensor to measure the weight of the objects to be weighed. In this case, the objects to be weighed may be supplied to the second hopper automatically or manually by an operator.

[0086] From the above description, many improvements and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present invention. [Industrial Applicability]

[0087] INDUSTRIAL APPLICABILITY The present invention is useful as a combination weigher and a control method for a combination weigher that can improve productivity. [Explanation of symbols]

[0088] 1 Weighing conveyor 3. Conveyor 5. Control device 11 Weighing object detection section 31 Collection Hopper 41 Route opening and closing section

Claims

1. a transport conveyor that transports the objects to be weighed in one direction and discharges them to a downstream device; a plurality of object holding sections for temporarily holding the objects to be weighed and then discharging the objects from discharge ports to supply the objects to the transport conveyor, the discharge ports being disposed at respective predetermined positions with respect to a transport direction of the transport conveyor; a combination processing unit that repeatedly performs a combination process to find one discharge combination consisting of a combination of the object holding units whose total weight of the objects held therein falls within a target weight range; a timing derivation unit which determines a start timing of a discharge operation of each of the object holding units based on the positions of the discharge ports of the object holding units selected for the discharge combination and the conveying speed of the conveyor each time the discharge combination is determined by the combination process, so that the objects to be discharged from each of the object holding units selected for the discharge combination are positioned at the same position on the conveyor; an operation control unit that causes the transport conveyor to start a transport operation and causes the weighed object holding unit to start a discharge operation based on the start timing determined by the timing derivation unit every time a discharge request signal is input from the subsequent stage device, and further causes the transport conveyor to finish its transport operation after causing the transport conveyor to start a transport operation and transport the objects to be discharged from the weighed object holding unit so that the objects to be weighed stop in a transport terminal area of ​​the transport conveyor, In this combination weigher, the combination processing unit performs combination processing and the operation control unit does not cause the conveying conveyor to start a conveying operation until the discharge request signal is input when the object to be weighed discharged from the object to be weighed holding unit is transported by the conveying conveyor and stopped at the conveying terminal area of ​​the conveying conveyor.

2. The timing derivation unit includes: each time the discharge combination is determined by the combination process, a timing to end the conveying operation of the conveyor is determined based on the position of the discharge port of the weighed object holding unit that is located furthest upstream in the conveying direction of the conveyor among the weighed object holding units selected for the discharge combination, so that the weighed objects discharged from the weighed object holding units and conveyed by the conveyor will stop in a conveying terminal area of ​​the conveyor; The operation control unit is After the transport conveyor starts a transport operation, the transport conveyor is caused to end the transport operation based on the end timing calculated by the timing derivation unit. The combination weigher according to claim 1.

3. A transport conveyor that transports the objects to be weighed in one direction and discharges them to a downstream device; a plurality of object holding sections for temporarily holding the objects to be weighed and then discharging the objects from discharge ports to supply the objects to the transport conveyor, the discharge ports being disposed at respective predetermined positions with respect to a transport direction of the transport conveyor; a combination processing unit that repeatedly performs a combination process to find one discharge combination consisting of a combination of the object holding units whose total weight of the objects held therein falls within a target weight range; a timing derivation unit which determines a start timing of a discharge operation of each of the object holding units based on the positions of the discharge ports of the object holding units selected for the discharge combination and the conveying speed of the conveyor each time the discharge combination is determined by the combination process, so that the objects to be discharged from each of the object holding units selected for the discharge combination are positioned at the same position on the conveyor; an operation control unit that causes the transport conveyor to start a transport operation and causes the weighed object holding unit to start a discharge operation based on the start timing determined by the timing derivation unit every time a discharge request signal is input from the subsequent stage device, and further causes the transport conveyor to finish its transport operation after causing the transport conveyor to start a transport operation and transport the objects to be discharged from the weighed object holding unit so that the objects to be weighed stop in a transport terminal area of ​​the transport conveyor; a weighing object detection unit that detects weighing objects present in a transport end area of ​​the transport conveyor, The operation control unit is The apparatus is configured to cause the transport conveyor to end the transport operation when an object to be weighed is newly detected by the object to be weighed detection unit while the transport conveyor is performing the transport operation. Combination scale.

4. a collecting hopper for receiving the objects to be weighed discharged from the discharge end of the transport conveyor, temporarily holding the objects, and then discharging the objects to the downstream device; The operation control unit is When a discharge request signal is input from the subsequent device, the objects to be weighed are immediately discharged from the collecting hopper. The combination weigher according to any one of claims 1 to 3.

5. A transport conveyor that transports the objects to be weighed in one direction and discharges them to a subsequent device; a plurality of object holding sections for temporarily holding the objects to be weighed and then discharging the objects from discharge ports to supply the objects to the transport conveyor, the discharge ports being disposed at respective predetermined positions with respect to a transport direction of the transport conveyor; a combination processing unit that repeatedly performs a combination process to find one discharge combination consisting of a combination of the object holding units whose total weight of the objects held therein falls within a target weight range; a timing derivation unit which determines a start timing of a discharge operation of each of the object holding units based on the positions of the discharge ports of the object holding units selected for the discharge combination and the conveying speed of the conveyor each time the discharge combination is determined by the combination process, so that the objects to be discharged from each of the object holding units selected for the discharge combination are positioned at the same position on the conveyor; an operation control unit that causes the transport conveyor to start a transport operation and causes the weighed object holding unit to start a discharge operation based on the start timing determined by the timing derivation unit every time a discharge request signal is input from the subsequent stage device, and further causes the transport conveyor to finish its transport operation after causing the transport conveyor to start a transport operation and transport the objects to be discharged from the weighed object holding unit so that the objects to be weighed stop in a transport terminal area of ​​the transport conveyor; a path opening / closing unit that switches between closing and opening a discharge path for the objects to be weighed, at a discharge end of the transport conveyor; The path opening / closing unit is configured to open the discharge path to enable discharge of the objects to be weighed from the conveyor during a period from the start of the conveying operation of the conveyor until a predetermined time has elapsed, and to close the discharge path to prevent discharge of the objects to be weighed from the conveyor during periods other than the period. Combination scale.

6. The object to be weighed holding unit is The weighing conveyor is configured such that, when the conveyance is stopped, the objects to be weighed are supplied, the objects are temporarily held and weighed, and the objects are conveyed for a predetermined period of time, thereby discharging the held objects to the conveying conveyor. The combination weigher according to any one of claims 1 to 5.

7. a transport conveyor that transports the objects to be weighed in one direction and discharges them to a downstream device; a plurality of object holding sections for temporarily holding the objects to be weighed and then discharging the objects from discharge ports to supply the objects to the transport conveyor, the discharge ports being disposed at respective predetermined positions with respect to a transport direction of the transport conveyor; A method for controlling a combination weigher comprising: repeating a combination process for determining one discharge combination consisting of a combination of the object holding parts, the total weight of the objects held by the object holding parts being within a target weight range; each time the discharge combination is determined by the combination process, a timing derivation process is performed to determine the start timing of the discharge operation of each of the object holding units based on the positions of the discharge outlets of the object holding units selected for the discharge combination and the conveying speed of the conveyor so that the objects to be discharged from each of the object holding units selected for the discharge combination are positioned at the same position on the conveyor; each time a discharge request signal is input from the subsequent stage device, the transport conveyor is caused to start a transport operation and the weighed object holding section is caused to start a discharge operation based on the start timing determined by the timing derivation process, and further, after the transport conveyor is caused to start a transport operation, an operation control process is performed in which the transport conveyor is caused to end its transport operation by transporting the objects to be discharged from the weighed object holding section and causing the objects to stop in a transport terminal area of ​​the transport conveyor; the combination process is performed and the conveyor is not caused to start a conveying operation until the discharge request signal is input when the objects to be weighed discharged from the object holding section are conveyed by the conveyor and stopped at a conveying end area of ​​the conveyor. A method for controlling a combination weigher.

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