Measuring device

Abstract

To provide a measuring device that can enhance both a measuring ability and measurement accuracy.SOLUTION: A measuring device 1 comprises: a feeder 3; a conveyance conveyer 16 that receives and conveys an article A to be discharged from the feeder 3 to a downstream; a mass acquisition unit 25 that acquires a loading mass of the article A on the conveyance conveyer 16, and a total discharge mass of the article A discharged from the conveyance conveyer 16; and a control unit 30 that controls operations of the feeder 3 and conveyance conveyer 16 on the basis of the loading mass of the article A and total discharge mass thereof. The control unit 30 is configured to: monitor a sum mass of the loading mass of the article A and total discharge mass thereof; stop the feeder 3 at a timing at which the sum mass reaches a preliminarily set target mass; and thereafter, cause the article on the conveyance conveyer 16 to discharge.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a weighing device.

Background Art

[0002] For example, as described in Patent Document 1, there is known a device that includes a supply feeder and a conveyor and continuously supplies articles in a fixed quantity. The supply feeder continuously supplies articles onto the conveyor. The belt of the conveyor circulates between the upstream pulley and the downstream pulley. The load sensor supports the weighing table, the conveyor, the two pulleys, and the drive motor of the conveyor, and detects their weights integrally. The control device measures the weight flow rate of the articles on the belt of the conveyor traveling on the weighing table, and controls the drive of the supply feeder so that the measured weight flow rate matches the set target weight flow rate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, as methods for measuring the target weight value in a conventional weighing device, the following two can be mentioned. The first method is to slow down the speed of the conveyor while supplying articles to the conveyor so that the articles are discharged from its discharge end, and when the weight of the articles stored in layers on the conveyor reaches the target weight for one batch, the articles stored on the conveyor are discharged by increasing the conveying speed. The second method is to discharge articles from the discharge end while supplying articles to the conveyor, obtain the flow rate per unit time at that time, and stop the discharge from the conveyor when the integrated value of the obtained flow rate reaches the target weight for one batch.

[0005] The first method described above has the advantage of high weighing accuracy because the items are weighed while being stored on the conveyor belt. However, it has the disadvantage that the amount of items that can be stored is limited, making it difficult to use when weighing large quantities of items. On the other hand, the second method described above can weigh large quantities of items, but it has the problem that the zero point cannot be adjusted when the items are on the conveyor belt at the time of weighing completion. To solve this problem, in the second method, for example, the supply of items to the conveyor belt could be stopped a little before the target weight is reached, thereby removing all the items on the conveyor belt and updating the zero point. However, although this method is superior to the first method in terms of processing capacity, it has the disadvantage that high weighing accuracy cannot be obtained.

[0006] The present invention aims to provide a weighing device that can improve both weighing capacity and weighing accuracy. [Means for solving the problem]

[0007] A weighing device according to one aspect of the present invention comprises an upstream transport unit that receives articles transported from upstream and transports them downstream; a downstream transport unit that receives articles discharged from the upstream transport unit and transports them downstream; a mass acquisition unit that acquires the loaded mass of articles on the downstream transport unit and the total discharged mass of articles discharged from the downstream transport unit; and a control unit that controls the operation of the upstream transport unit and the downstream transport unit based on the loaded mass of articles and the total discharged mass acquired by the mass acquisition unit. The control unit monitors the total mass of the loaded mass of articles and the total discharged mass acquired by the mass acquisition unit while operating the upstream transport unit and the downstream transport unit, and stops the upstream transport unit when the total mass reaches a preset target mass, and then discharges the articles on the downstream transport unit.

[0008] In this weighing device, the mass acquisition unit acquires the loaded mass of the items on the downstream conveying unit and the total discharged mass of the items from the downstream conveying unit. The control unit monitors the sum of the loaded mass and the total discharged mass. Conveying and weighing are performed continuously until the sum of the loaded mass and the total discharged mass (total mass) approaches the target mass. When the sum of the loaded mass and the total discharged mass reaches the target mass, the discharge of items from the upstream conveying unit is stopped. At this time, the downstream conveying unit is loaded with items corresponding to the loaded mass at the time the upstream conveying unit stopped. By discharging all of these items, the cumulative mass of the discharged items will correspond to the target mass. This allows the downstream conveying unit to be kept unloaded until the next batch weighing. For example, if the zero point of the downstream conveying unit is taken during this time, the weighing accuracy of the downstream conveying unit can be maintained at a high level. In this respect, it is superior to the second method described above. Furthermore, since this weighing device also calculates the flow rate of goods discharged from the downstream conveying section, it can weigh a larger quantity of goods than the first method described above. Therefore, this weighing device can improve both weighing capacity and weighing accuracy.

[0009] The control unit may reduce the discharge rate of items from the upstream conveying unit when the total mass reaches a predetermined mass that is less than the target mass. With this configuration, when the upstream conveying unit is stopped just before the total mass reaches the target mass from the predetermined mass, the amount of items discharged due to inertia can be minimized. This enables more accurate weighing than the second method described above. Furthermore, the discharge rate of items per unit time from the upstream conveying unit may be set as high as possible until the total mass reaches the predetermined mass. In this way, by switching the discharge rate from the upstream conveying unit in two stages, it is possible to increase weighing capacity while maintaining high weighing accuracy.

[0010] When the control unit stops the upstream transport unit after the total mass reaches the target mass, it may increase the transport speed of the downstream transport unit to discharge the items on the downstream transport unit. With this configuration, as soon as the system recognizes that the total mass has reached the target mass, the items on the downstream transport unit are discharged all at once, thereby further increasing the weighing capacity while maintaining high weighing accuracy.

[0011] The control unit may, after the discharge of items from the downstream transport unit is complete, stop the downstream transport unit and store the tare mass of the downstream transport unit as the zero point. If batch weighing is repeated, the zero point may gradually change, but if zero point adjustment is performed after the discharge of items from the downstream transport unit, the zero point adjustment will be performed, for example, each time, thus maintaining high weighing accuracy. [Effects of the Invention]

[0012] According to the present invention, both weighing capacity and weighing accuracy can be improved. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a side view of a weighing device according to one embodiment. [Figure 2] Figure 2 is a plan view of a weighing device according to one embodiment. [Figure 3] Figure 3 is a block diagram showing the functional configuration of the weighing device shown in Figures 1 and 2. [Figure 4] Figure 4 is a flowchart illustrating the operation of the weighing device. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings.

[0015] First, the schematic configuration of the weighing device 1 according to this embodiment will be described with reference to Figures 1 and 2. The weighing device 1 is a device that quantitatively weighs an item A of a target mass using a weighing conveyor 4. Item A is, for example, food, and includes a large number of constituent pieces that are powders, granules, or the smallest units having some shape. Each constituent piece may include containers or packaging that package or contain the food. Item A may also be any other material (workpiece) other than food that requires quantitative weighing.

[0016] As shown in Figures 1 and 2, the weighing device 1 includes a bucket conveyor 2 that receives and transports article A from a hopper or the like (not shown) located upstream, a feeder (upstream transport section) 3 that receives article A transported from the bucket conveyor 2 and transports it downstream, and a weighing conveyor 4 that receives article A transported from the feeder 3, measures the mass of article A, and transports it downstream. The weighing device 1 further includes a discharge conveyor 5 that receives and transports article A discharged from the weighing conveyor 4 and discharges article A to another line downstream (a line for packaging, etc.) (not shown).

[0017] Furthermore, in the weighing device 1, the configuration other than the feeder 3 and weighing conveyor 4 can be changed as appropriate. The conveying and supplying equipment provided upstream of the feeder 3 is not limited to the bucket conveyor 2. The conveying and supplying equipment provided downstream of the weighing conveyor 4 is not limited to the discharge conveyor 5. Another conveyor may be provided on the conveying surface 22a of the discharge conveyor 5 for introducing and mixing other items. After the quantitative weighing of item A is performed by the feeder 3 and weighing conveyor 4, changes may be made as appropriate depending on the types of item A and other items to be quantitatively weighed, and the overall process and layout of the manufacturing equipment.

[0018] The bucket conveyor 2 has multiple buckets 6 that orbit a track, and transports the goods A contained in the buckets 6 in a predetermined direction and discharges them to the feeder 3. Each bucket 6 has a trough-shaped or semi-cylindrical storage space that is long in the width direction. Adjacent buckets 6 are arranged continuously such that the front and rear flanges 6a provided at the upper end of each bucket 6 in the transport direction overlap. In detail, the flange 6a of the rear bucket 6 is tucked under the flange 6a of the bucket 6 located on the front side in the transport direction. The front end of the track is located above the feeder 3, and goods A are supplied to the feeder 3 when the bucket 6 located at the front end of the track reverses. The operation and stopping of the bucket conveyor 2 may be controlled in conjunction with the operation and stopping of the feeder 3, for example, by the control unit 30 of the weighing conveyor 4, which will be described later.

[0019] The feeder 3 has a base portion 11 fixed to the installation surface of the device, and a stock trough 10 provided on the base portion 11 and supported by the base portion 11. An electromagnetic vibrator 14 is provided between the stock trough 10 and the base portion 11. The lower end of the electromagnetic vibrator 14 is fixed to the base portion 11, and the stock trough 10 is fixed to the upper end of the electromagnetic vibrator 14. The base portion 11 includes a plurality of coil springs 12 and a support base 13 supported by the coil springs 12. The feeder 3 is controlled, for example, by the control unit 30 of the weighing conveyor 4, which vibrates the electromagnetic vibrator 14 at a predetermined amplitude. The stock trough 10 supported by the electromagnetic vibrator 14 has a certain (sufficient) storage space, and vibrates in accordance with the vibration of the electromagnetic vibrator 14 to transport article A in the transport direction and discharge article A from an open portion (discharge portion) at the front end in the transport direction.

[0020] The amplitude of the electromagnetic vibrator 14 in the feeder 3 is controlled and adjusted by, for example, the control unit 30. By increasing the amplitude, the discharge amount of the article A from the feeder 3 can be increased. By decreasing the amplitude, the discharge amount of the article A from the feeder 3 can be decreased. The feeder 3 can be switched and controlled for the discharge amount by the control unit 30. In this specification, the "discharge amount" refers to the mass of the article A discharged (supplied to the weighing conveyor 4) per unit time. The discharge amount in the feeder 3 may be switched and controlled in two steps, or may be switched and controlled in three or more steps. The feeder 3 is operable, for example, to realize a rated (standard) discharge amount set to the maximum according to the type of the article A and the target value (target mass) of the quantitative weighing, and one or two or more reduced discharge amounts smaller than the rated discharge amount.

[0021] For example, a chute 20 is provided between the feeder 3 and the weighing conveyor 4. The chute 20 has a width that is longer than the width of the stock trough 10 and shorter than the width of the belt 18 in the width direction orthogonal to the conveying direction D of the weighing conveyor 4. The chute 20 is disposed below the front end in the conveying direction of the stock trough 10, and causes the article A to fall (slide) on a sliding surface having a predetermined angle, and discharges (supplies) the article A onto the conveying surface 18a of the weighing conveyor 4. The pair of side walls 10a of the stock trough 10 and the pair of side guide plates 19 of the conveying conveyor 16 prevent the article A from falling out of the conveying path. Thereby, the article A conveyed by the feeder 3 is received by the weighing conveyor 4 without spilling.

[0022] The weighing conveyor 4 has a conveying conveyor 16 including a belt 18 that circulates on a track and a pair of pulleys 17 provided at the front end and the rear end of the track. The conveying conveyor 16 is controlled by a control unit 30 to convey the article A in the conveying direction D. The conveying speed in the conveying conveyor 16 may be generally set according to the discharge amount by the feeder 3 (for example, the above-mentioned rated discharge amount), and is set at a constant speed, for example. The conveying speed in the conveying conveyor 16 is adjustable. The conveying conveyor 16 can run the belt 18 at a maximum conveying speed greater than the conveying speed set according to the discharge amount by the feeder 3.

[0023] At positions on both sides in the width direction of the belt 18, the pair of side guide plates 19 are fixed to places other than the belt 18 by brackets or the like. The conveying conveyor 16 includes a weighing table disposed below the conveying surface 18a of the belt 18 and a motor (both not shown) that drives the pulley 17 to run the belt 18. The weighing conveyor 4 has a main body portion 15 provided below the belt 18. The main body portion 15 has a detection portion including a load cell or the like having one end connected to the weighing table. The main body portion 15 supports the conveying conveyor 16 and detects the tare weight obtained by combining the mass of the conveying conveyor 16 and the mass of the article A placed on the conveying surface 18a.

[0024] The discharge conveyor 5 has a belt 22 that circulates on a track. A chute 21 is provided, for example, between the weighing conveyor 4 and the discharge conveyor 5. The chute 21 is disposed at the downstream end in the conveying direction D of the belt 18, and causes the article A to fall (slide) on a sliding surface having a predetermined angle, and discharges (supplies) the article A onto the conveying surface 22a of the belt 22 of the discharge conveyor 5. The pair of side guide plates 23 of the discharge conveyor 5 prevent the article A from falling. The discharge conveyor 5 is controlled by, for example, the control unit 30 of the weighing conveyor 4 or another controller and operates continuously.

[0025] Next, with reference to Figure 3, the functional configuration of the weighing device 1 will be described. As shown in Figure 3, the weighing conveyor 4 comprises the transport conveyor 16 described above, a mass acquisition unit 25 that acquires the mass of item A, and a control unit 30 that performs predetermined calculation processing based on the mass of item A acquired by the mass acquisition unit 25 and controls the feeder 3 and the transport conveyor 16. The mass acquisition unit 25 and the control unit 30 are provided, for example, within the main body 15.

[0026] The mass acquisition unit 25 includes a load mass acquisition unit 26 that acquires the load amount of article A on the conveying surface 18a of the conveying conveyor 16, and a total discharge mass acquisition unit 27 that acquires the total discharge mass of article A discharged from the conveying conveyor 16. The load mass acquisition unit 26 acquires the load amount of article A by receiving a detection signal from the detection unit of the weighing conveyor 4. The load mass acquisition unit 26 acquires and stores the load amount of article A, for example, at predetermined intervals. The total discharge mass acquisition unit 27 calculates the discharge mass per unit time (article discharge rate) on the conveying conveyor 16 based on the load mass acquired by the mass acquisition unit 25 and the conveying speed of the conveying conveyor 16. The total discharge mass acquisition unit 27 further calculates the total discharge mass since batch weighing started in the weighing device 1 by integrating the discharge mass per unit time (article discharge rate) over time. Therefore, the calculation begins based on the elapsed time from the moment item A is discharged from the conveyor belt 16.

[0027] For example, if the mass of item A loaded onto the conveyor belt 16 from the starting point to the end point by the supply of items from feeder 3 is W (g), then the mass of item A per unit length on the conveyor belt 16 is W / L (g / m). Also, if the conveying speed of the conveyor belt 16 is V (m / sec), then the mass Q discharged per unit time transported by the conveyor belt 16 is: Q = (W / L) * V (g / sec) And the total mass discharged from feeder 3 at time T (sec) after feeder 3 and conveyor belt 16 have been driven simultaneously is: Total mass = Load mass W + Q·(Tt) on the conveyor belt 16 calculated at time T The formula is as follows: where t(sec) is the transport time required for item A supplied to the transport conveyor 16 to be discharged to the discharge conveyor 5. Also, the loaded mass W is the average value of multiple sampled weighing values.

[0028] The control unit 30 is a device that controls various operations in the weighing device 1, and is a signal processing device equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The control unit 30 may also have the function of the total discharge mass acquisition unit 27 in the mass acquisition unit 25. The control unit 30 includes a total mass calculation unit 31, a judgment unit 32, a conveyor control unit 33, a feeder control unit 34, and a zero-point adjustment unit 35.

[0029] The total mass calculation unit 31 calculates the sum of the load on item A on the conveying surface 18a, which is acquired or calculated by the mass acquisition unit 25, and the total discharged mass since the start of batch weighing. The determination unit 32 determines whether the total mass has reached a predetermined mass that has been stored in advance. The determination unit 32 also determines whether the total mass has reached a target mass that has been stored in advance.

[0030] The conveyor control unit 33 controls the operation or stopping of the transport conveyor 16. The conveyor control unit 33 can change the transport speed on the transport conveyor 16. The feeder control unit 34 controls the operation or stopping of the feeder 3. The feeder control unit 34 can change the discharge rate on the feeder 3. The zero-point adjustment unit 35 performs zero-point adjustment by storing the tare mass of the transport conveyor 16 as the zero point while the transport conveyor 16 is stopped.

[0031] Next, with reference to Figure 4, the process (weighing method) when quantitative weighing of item A is performed by the weighing device 1 will be explained. Figure 4 is a flowchart for explaining the operation of the weighing device. First, the weighing device 1 is started, for example, by an operator pressing the start button (step S01). The control unit 30 of the weighing device 1 stores (sets) a target mass corresponding to item A, and a predetermined mass that is slightly smaller than the target mass. The predetermined mass is, for example, a value within the range of 95 to 99% of the target mass.

[0032] Next, the zero-point adjustment unit 35 of the control unit 30, upon receiving the operation start signal, performs zero-point adjustment by storing the tare mass of the conveyor belt 16 as the zero point (step S02). Subsequently, once the zero-point adjustment is complete, the conveyor control unit 33 drives the conveyor belt 16, and the feeder control unit 34 drives the feeder 3 (step S03). The conveyor control unit 33 drives the conveyor belt 16 to travel at a predetermined conveying speed. The feeder control unit 34 drives the feeder 3 to discharge item A at the rated discharge rate. Simultaneously with the driving of the feeder 3, the upstream supply equipment (including the bucket conveyor 2) may also be driven. Once item A is transported and discharged by the feeder 3, item A is placed on the conveying surface 18a of the weighing conveyor 4, and item A begins to be transported by the conveyor belt 16. Batch weighing begins with this step S03.

[0033] Next, the mass acquisition unit 25 acquires the load amount of item A on the conveying surface 18a and the total discharge mass since batch weighing began (step S04). The total mass calculation unit 31 of the control unit 30 calculates the total mass based on the load mass and total discharge mass acquired in step S04 (step S05). In this embodiment, the weighing device 1 monitors the total mass by adding (taking into account) the load mass of item A currently placed on the conveying conveyor 16, as well as the total discharge mass. The calculation of the total mass is performed at predetermined time intervals while this series of processes is being carried out.

[0034] Next, the determination unit 32 of the control unit 30 determines whether the total mass has reached a predetermined mass (step S06). The determination unit 32 determines whether the total mass calculated in step S05 is greater than or equal to a predetermined mass stored in advance, or less than the predetermined mass. If the determination unit 32 determines that the total mass is less than the predetermined mass (step S06; NO), the process in step S04 is performed. If the determination unit 32 determines that the total mass is greater than or equal to the predetermined mass (step S06; YES), the feeder control unit 34 reduces the item transport speed of the feeder 3 by reducing the amplitude of the feeder 3 (step S07). Specifically, the feeder control unit 34 controls the amplitude of the feeder 3 so that the feeder 3 discharges item A at a discharge rate smaller than the previous rated discharge rate. In this way, the weighing device 1 reduces the discharge rate by the feeder 3 when the total mass approaches the target mass.

[0035] By the time step S07 is performed, the total mass of item A, which is the sum of the amount already discharged from the transport conveyor 16 to the discharge conveyor 5 and the load mass on the transport conveyor 16, is approaching the target mass. In this state, the determination unit 32 of the control unit 30 determines whether the total mass has reached the target mass (step S08). The determination unit 32 determines whether the total mass is greater than or equal to a pre-stored target mass, or less than the target mass. If the determination unit 32 determines that the total mass is less than the target mass (step S08; NO), it repeats the determination in step S08. If the determination unit 32 determines that the total mass is greater than or equal to the target mass (step S08; YES), the feeder control unit 34 stops the feeder 3 (step S09).

[0036] Next, the conveyor control unit 33 increases the transport speed of the transport conveyor 16 (step S10). For example, the conveyor control unit 33 controls the transport conveyor 16 to run the belt 18 at a maximum transport speed that is faster than the transport speed in step S03. This control in step S10 causes the item A on the transport conveyor 16 to be discharged all at once onto the discharge conveyor 5. The conveyor control unit 33 stops the transport conveyor 16 when the discharge of item A is complete (step S11). The "discharge completion timing" between steps S10 and S11 may be determined according to the time determined based on the transport speed (maximum transport speed) of the transport conveyor 16, or it may be determined when the load mass detected by the load mass acquisition unit 26 has stabilized at a sufficiently low value.

[0037] The series of processes described above completes one batch weighing operation in the weighing device 1. After the conveyor belt 16 stops, the zero-point adjustment in step S02 is performed, and the next batch weighing operation begins. In the weighing method of this embodiment, the total mass of the items A discharged from the feeder 3 is monitored, and the feeder 3 stops when the total mass reaches the target mass, after which the items on the conveyor belt 16 are discharged.

[0038] According to the weighing device 1 and weighing method of this embodiment, the mass acquisition unit 25 acquires the loaded mass of article A on the conveyor belt 16 and the total discharged mass of article A from the conveyor belt 16, and the control unit 30 monitors the sum of the loaded mass and the total discharged mass. Then, conveying and weighing are carried out continuously until the sum of the loaded mass and the total discharged mass (total mass) approaches the target mass, and the discharge of article A from the feeder 3 is stopped at the timing when the sum of the loaded mass and the total discharged mass reaches the target mass. At this timing, the conveyor belt 16 is loaded with article A corresponding to the loaded mass at the time the feeder 3 stopped, so by discharging all of it, the cumulative mass of the discharged article A will correspond to the target mass. As a result, the conveyor belt 16 can be kept in an unloaded state until the next batch weighing, so if the zero point of the conveyor belt 16 is taken during that time, the weighing accuracy of the conveyor belt 16 can be maintained at a high accuracy. Furthermore, since this weighing device 1 also calculates the flow rate of item A discharged from the conveyor belt 16, it can weigh a large quantity of item A. Therefore, this weighing device 1 can improve both weighing capacity and weighing accuracy.

[0039] The control unit 30 reduces the discharge rate of item A from the feeder 3 when the total mass reaches a predetermined mass that is less than the target mass. This minimizes the amount of item A discharged due to inertia when the feeder 3 is stopped just before the total mass reaches the target mass from the predetermined mass. This enables more accurate weighing. Furthermore, until the total mass reaches the predetermined mass, the amount of item discharged per unit time from the feeder 3 is set to be as high as possible. In this way, by switching the discharge rate from the feeder 3 in two stages, it is possible to increase weighing capacity while maintaining high weighing accuracy.

[0040] When the control unit 30 stops the feeder 3 after the total mass reaches the target mass, it increases the transport speed of the transport conveyor 16 and discharges the items A on the transport conveyor 16. As a result, as soon as the system recognizes that the total mass has reached the target mass, the items on the transport conveyor 16 are discharged all at once, which further enhances the weighing capacity while maintaining high weighing accuracy.

[0041] When the discharge of item A from the conveyor belt 16 is complete, the control unit 30 stops the conveyor belt 16 and stores the tare mass of the conveyor belt 16 as the zero point. If batch weighing is repeated, the zero point may gradually change, but if zero point adjustment is performed after the discharge of item A from the conveyor belt 16, zero point adjustment is performed each time, thus maintaining high weighing accuracy.

[0042] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the upstream conveying section may have a different configuration from the vibrating feeder 3 of the above embodiment. For example, it may be a belt conveyor that conveys articles while leveling them to a certain thickness. In this case, the conveyor speed is switched from high speed to low speed to reduce the amount of material being conveyed. Furthermore, the downstream conveying section was a weighing conveyor 4 in which the entire conveying conveyor 16 including the motor is supported by load sensors such as load cells, but it is not limited to this. As the downstream conveying section, for example, a belt scale may be used in which the moving belt is directly supported by load sensors to determine the amount of material being conveyed per unit time, and the total discharge mass is determined by integrating the determined amount of material being conveyed over time.

[0043] In the above embodiment, a two-stage switching control was performed to reduce the discharge amount from the feeder 3 when the total mass approached the target mass (when it reached a predetermined mass), but the invention is not limited to this example. The feeder 3 may be driven at a predetermined discharge amount until the total mass reaches the target mass, or a multi-stage (three or more stages) switching control may be performed to reduce the discharge amount from the feeder 3 in multiple stages. Furthermore, a gradual reduction control may be performed to gradually decrease the discharge amount from the feeder 3 from the point when the total mass reaches a predetermined mass.

[0044] The control in step S10 after feeder 3 stops (maximum speed discharge control of conveyor 16) may be omitted.

[0045] Zero-point adjustment does not have to be performed after each batch weighing is completed; it may be performed after a certain number of batch weighings have been completed. A higher frequency of zero-point adjustment helps maintain higher weighing accuracy. For example, when weighing item A, which tends to adhere to the belt 18, the frequency of zero-point adjustment should be increased (performed every time), while when weighing item A, which does not tend to adhere to the belt 18, the frequency of zero-point adjustment may be decreased.

[0046] In the above embodiment, an example was described in which the control unit 30 is provided on the weighing conveyor 4, but the control unit may be provided outside the weighing conveyor 4. The control unit only needs to be able to control the feeder 3 and the transport conveyor 16 by wired communication or wireless communication. [Explanation of Symbols]

[0047] 1...Weighing device, 2...Bucket conveyor, 3...Feeder (upstream conveying section), 4...Weighing conveyor, 5...Discharge conveyor, 16...Conveying conveyor (downstream conveying section), 17...Pulley, 18...Belt, 18a...Conveying surface, 25...Mass acquisition unit, 30...Control unit, 31...Total mass calculation unit, 33...Conveyor control unit, 34...Feeder control unit, 35...Zero point adjustment unit, A...Item, D...Conveying direction.

Claims

1. The upstream transport unit receives food transported from upstream and transports it downstream, A downstream conveying unit receives the food discharged from the upstream conveying unit and conveys it downstream, A load mass acquisition unit that acquires the load mass of the food placed on the conveying surface of the downstream conveying unit, A total discharge mass acquisition unit calculates the total discharge mass of the food discharged from the downstream transport unit based on the load mass acquired by the load mass acquisition unit and the transport speed of the downstream transport unit, The system includes a control unit that controls the operation of the upstream transport unit and the downstream transport unit based on the load mass obtained by the load mass acquisition unit and the total discharge mass calculated by the total discharge mass acquisition unit, The control unit operates the upstream transport unit and the downstream transport unit while monitoring the total mass of the load mass obtained by the load mass acquisition unit and the total discharge mass calculated by the total discharge mass acquisition unit, stops the upstream transport unit when the total mass reaches a preset target mass, then discharges the food on the downstream transport unit, and when the discharge of the food on the downstream transport unit is completed, stores the tare mass of the downstream transport unit as the zero point while the downstream transport unit is stopped, in a weighing device.

2. The weighing device according to claim 1, wherein the control unit reduces the amount of food discharged from the upstream conveying unit when the total mass reaches a predetermined mass that is less than the target mass.

3. The weighing device according to claim 1 or 2, wherein when the total mass reaches the target mass and the upstream transport unit stops, the control unit increases the transport speed of the downstream transport unit to discharge the food on the downstream transport unit.

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