KR100728880B1 - Apparatus for measuring weight automatically - Google Patents

Abstract

The present invention relates to an automatic cargo weighing apparatus, and more particularly, to an automatic cargo weighing apparatus capable of automatically measuring the weight of an object moving on a conveyor belt.

Automatic cargo weighing apparatus according to the present invention includes a conveyor frame including a conveyor belt for transferring the loaded cargo, and a drive means for driving the conveyor belt; A bad frame installed at a lower end of the conveyor frame to support the conveyor frame; Load cells installed at a mechanical center according to the center of gravity of the conveyor frame and provided between the conveyor frame and the bad frame and outputting a measurement signal according to the weight of the cargo to be transported; A controller for displaying the weight information of the cargo calculated by the apparatus, and a controller for controlling the overall apparatus, receiving a measurement signal output from the load cell to calculate the weight of the cargo and displaying the weight on the display. It is configured to include.

Cargo, Weight, Conveyor, Load Cell

Description

Apparatus for measuring weight automatically

Figure 1a is a perspective view schematically showing an automatic load weighing apparatus according to an embodiment of the present invention.

Figure 1b is a schematic front view of the automatic load weighing apparatus according to an embodiment of the present invention.

FIG. 1C is a main view showing a position where a load cell is installed according to FIGS. 1A to 1B.

2A is a perspective view schematically illustrating a first load cell according to an exemplary embodiment of the present invention.

FIG. 2B is a cross-sectional view of main parts illustrating a state in which the first load cell according to FIG. 2A is coupled to the conveyor frame and the bad frame.

Figure 2c is a perspective view schematically showing a second load cell according to an embodiment of the present invention.

Figure 2d is a cross-sectional view of the main part showing a state in which the second load cell according to Figure 2c is coupled to the conveyor frame and the bad frame.

Figure 3 is a block diagram schematically showing a controller of the automatic cargo weighing apparatus according to an embodiment of the present invention.

4 is a flowchart schematically illustrating a weight calculation process of a control unit according to an exemplary embodiment of the present invention.

The present invention relates to an automatic cargo weighing apparatus, and more particularly, to an automatic cargo weighing apparatus capable of automatically measuring the weight of an object moving on a conveyor belt.

 With the development of mass media such as TVs and the Internet, commerce can be easily handled, and operators such as shopping malls are trying to provide faster and more convenient services to customers. This increase in commerce leads to an increase in the volume of logistics, such as courier and freight, and the operators in charge of logistics management aims to deliver goods to the place where the customer wants the fastest and safest. This demand is made possible by the introduction of fast and accurate automated logistics systems.

Directly related to the profits of the logistics company that manages the logistics is the logistics cost of freight, and the freight billing information imposed on the consumer is the most sensitive and reliable part of both the consumer and the company. The most important information in freight billing is the weight of the cargo. Therefore, many logistics management companies are putting a lot of manpower and expensive equipment in order to accurately weigh the cargo.

 Such a conventional logistics management system has a problem that can not accurately and systematically manage logistics and waste of manpower and time.

In order to prevent this problem, in the related art, a load cell for measuring a weight is mounted on a predetermined portion of a conveyor device for transporting cargo, and the weight of the cargo in motion is measured.

However, the positional structure of the load cell mounted on such a device does not take into account the mechanical calculations that occur when the load cell is subjected to a load, and thus has a disadvantage in that different measurement results are shown depending on the position where the object is placed.

The present invention was devised to solve this problem, and an object thereof is to provide an automatic cargo weighing apparatus for automatically measuring the exact weight of a moving cargo without stopping for weighing.

It is another object of the present invention to provide an automatic cargo weighing apparatus that can be implemented with a low installation cost and a simple configuration.

 Furthermore, by providing an interface with an external device, it can be easily interlocked with the logistics management system without a separate sorting process and arrangement, and to provide an automatic cargo weighing device that can be computerized.

As described above, the automatic load weighing apparatus according to the preferred embodiment of the present invention is a conveyor frame including a conveyor belt for transferring the loaded cargo, a driving means for driving the conveyor belt, and a conveyor frame installed under the conveyor frame. The first frame and the bad frame for supporting the air frame, and is installed in the mechanical center according to the center of gravity of the conveyor frame, is provided between the conveyor frame and the bad frame, the first and outputs the measurement signal by detecting the load according to the weight of the conveyed cargo A display unit for displaying the second load cell, the weight information of the cargo calculated by the automatic load weighing device, and controls the overall device, receiving the measurement signal output from the load cell to calculate the weight of the load and display on the display It is configured to include a controller including a control unit.

Therefore, the automatic cargo weighing apparatus according to the present invention can accurately measure the weight of the cargo being transported by the conveyor, has the advantage that no separate weighing process is required.

According to a characteristic aspect of the present invention, the load cell of the automatic load measuring apparatus according to the present invention has a first load cell having a lower side fixedly coupled to a bad frame, an upper side fixedly coupled to a conveyor frame, and a lower side fixed to a bad frame. And a second load cell having a ball groove formed therein, the ball groove having a plurality of balls mounted thereon to transmit only the vertical load applied by the conveyor frame to the upper other side.

For accurate measurement of cargo weight, it is ideal to detect only the vertical load applied to the load cell. However, the conventional cargo weighing apparatus was not able to measure the exact weight of the cargo due to interference by the lateral load component generated during the movement of the cargo and the lateral load component caused by the conveyor driving.

Therefore, the load cell according to the present invention is equipped with a plurality of balls in point contact with the conveyor frame to the sensing means for detecting the load, it is possible to detect only the load acting perpendicular to all the load to ensure the linearity of the measured value It can be, and has the advantage of reducing the error of the measured value changes according to the external environment.

According to a characteristic aspect of the present invention, the load cells installed in the automatic cargo weighing apparatus according to the present invention are installed parallel to each other on the conveyor frame, and the positions fixed to the conveyor frame and the bad frame relative to the mechanical center of the conveyor frame are different from each other. It is characterized in that the installation in the opposite direction.

Therefore, by installing the load measurement direction of the load of the two load cells installed in the automatic load weighing device in different directions, there is an advantage that can solve the imbalance applied to the two load cells when loading and transporting the cargo. .

According to a characteristic aspect of the present invention, the controller of the controller of the automatic cargo weighing apparatus according to the present invention samples the measurement signals output from the first and second load cells at predetermined time intervals, and the time at which the corresponding cargo is transported to the predetermined number. Divide and group, calculate the average value of the sampling value of each group, extract the two groups with the larger average value among the groups where the average value is calculated, calculate the standard deviation between the sampling values of each group, and standard deviation The weight of the cargo is calculated using the sampling value of the lesser group.

Therefore, by calculating the group having the largest mean value and the smallest deviation among the plurality of groups and applying it to the weight calculation, it contributes to the precision of the measurement result and has the effect of coping with transient input.

According to a further aspect of the present invention, the controller according to the present invention may further include an interface unit for interfacing the cargo weight information calculated by the controller with an external device. Therefore, it can be easily interlocked with the logistics management system without a separate classification process and arrangement work, and has the advantage of computerization.

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand and reproduce the present invention.

Figure 1a is a perspective view schematically showing an automatic load weighing apparatus according to a preferred embodiment of the present invention, Figure 1b is a front view schematically showing an automatic load weighing apparatus according to a preferred embodiment of the present invention. 1C is a main view illustrating a position where load cells are installed according to FIGS. 1A to 1B.

Referring to Figures 1a to 1c, as shown in the automatic cargo weighing apparatus according to the present invention is a conveyor belt 110 for transporting the loaded cargo, drive means for driving the conveyor belt 110 (not shown) Conveyor frame 100 including a), the bad frame 200 is installed on the bottom of the conveyor frame 100 to support the conveyor frame 100, and coincident with the mechanical center of the center of gravity of the conveyor frame 100 It is installed so that the center is located, the load cells 300-1, 300-2 are provided between the conveyor frame 100 and the bad frame 200, and outputs a measurement signal according to the weight of the cargo to be transported, The display unit 410 for displaying the weight information of the cargo calculated by the device, and controls the overall device, receives the measurement signal output from the load cell to calculate the weight of the cargo and display on the display unit 410 Which consists of a controller (not shown), the controller (400) including a.

Conveyor frame 100 refers to the frame on which the conveyor is installed. Conveyor frame 100 has a metal material as a basic skeleton is installed a conveyor for cargo transfer. Conveyors are the main machinery used in industrial sites to transport goods loaded on belts using wide belts and multiple rollers. The conveyor is composed of a conveyor belt for transferring the loaded cargo, a drive motor for driving the conveyor belt, a drive motor controller 400 for controlling the drive motor and a drive means composed of a plurality of rollers. The conveyor automatically moves continuously between a certain distance by moving the belt by the drive motor and the rollers.

The bad frame 200 is coupled to the lower end of the conveyor frame 100 and is a kind of support means for supporting the conveyor frame 100 so that it can be installed more stably.

A load cell is an essential weighing element for electronic balances that numerically represent the applied load. When the load cell receives the weight, it is compressed or stretched, and the deformation is detected. When the amount of deformation is detected as an electric signal and then converted into a digital signal by a computer device, the weight is displayed as a number.

The load cells 300-1 and 300-2 according to the present invention are disposed on the lower side of the other side of the conveyor frame 100 so as to be parallel to the first load cell 310 installed at the portion where the load is loaded below the conveyor frame 100. It includes a second load cell 320 is installed.

According to a characteristic aspect of the present invention, a load cell according to the present invention will be described in more detail with reference to FIGS. 2A to 2C. 2A is a cross-sectional view illustrating main parts of a first load cell coupled to a conveyor frame and a bad frame according to a preferred embodiment of the present invention, and FIG. 2B schematically illustrates a second load cell according to a preferred embodiment of the present invention. Figure 2c is a perspective view, Figure 2c is a cross-sectional view of the main portion showing a state in which the second load cell according to Figure 2b coupled to the conveyor frame and the bad frame.

One side of the first load cell 310 is fixedly coupled to the bad frame 200, the other side is fixedly coupled to the conveyor frame (100). The combination of the first load cell 310 and the conveyor frame 100 and the bad frame 200 will be described in more detail with reference to FIG. 2A. As shown, the first load cell 310 according to the present invention is fixed by the lower one side is fixed to the rear frame, for example by a fixing means such as a screw or an anchor. A metal plate F is inserted and coupled between the rear frame and the first load cell 310. In addition, the upper other side of the first load cell 310 coupled with the conveyor frame 100 is also coupled through the metal plate (F).

Inserting and coupling the metal plate F to the lower one side of the first load cell 310 and the upper other side of the first load cell 310 is a load cell to which the load cell used in the present invention senses distortion caused by load. Because. When the cargo is loaded on the conveyor belt, the load cell is warped in accordance with the load applied by the cargo. The sensing means of the load cell outputs different measurement signals according to the degree of distortion of the load cell by the load. The measurement signal output from the load cell is used as data for calculating the weight of the controller.

For accurate measurement of cargo weight, it is ideal to detect only the vertical load applied to the load cell. However, the conventional cargo weighing apparatus was not able to measure the exact weight of the cargo due to interference by the lateral load component generated during the movement of the cargo and the lateral load component caused by the conveyor driving.

Accordingly, the second load cell 320 according to the present invention is the second load cell 320 is point contact to measure only the vertical load of the cargo transmitted from the conveyor frame 100 to measure only the vertical load applied by the cargo. A plurality of balls 322 are included.

In addition, the conveyor frame 100 has a ball groove (F-1) corresponding to the ball 322 mounted on the ball groove 321 of the second load cell 320 is cut. Therefore, the ball 322 can be prevented from being separated by disturbance by the ball groove 321 of the second load cell 320 and the ball groove (F-1) of the conveyor frame 100, it is taken more stably cargo Only the vertical load applied by

The coupling structure of the second load cell 320 and the conveyor frame 100 and the bad frame 200 will be described in more detail with reference to FIGS. 2B and 2C. As shown, the second load cell 320 according to the present invention is a plurality of balls fixedly coupled to the lower side of the bad frame 200, and transmits only the vertical load applied by the conveyor frame 100 to the other side of the upper ( 322 is a ball groove 321 is characterized in that it is formed.

Like the first load cell 310, the second load cell 320 is fixedly coupled to the bad frame 200 through the metal plate F. However, the upper other side is formed with a ball groove 321 that can be in point contact with the conveyor frame 100. In the present invention, four ball grooves 321 are formed, each ball 322 is mounted on the ball groove 321 and the conveyor frame 100 is loaded thereon. That is, the second load cell 320 is fixedly coupled to the lower side by the coupling means such as the bad frame 200, for example, a screw or an anchor, on the contrary, the upper other side of the ball mounted on the ball groove 321 Conveyor frame 100 is loaded above 322.

Accordingly, the second load cell 320 according to the present invention is equipped with a plurality of balls 322 in point contact with the conveyor frame 100 in the sensing means for detecting the load, thereby detecting only the load acting vertically for all loads This ensures the linearity of the measured values.

In addition, the second load cell 320 and the conveyor frame 100 is not fixedly coupled, but by point contact of the ball 322, for example, an error of a measured value changed according to an external environment such as a place where an apparatus is installed. Has the advantage of reducing.

According to another aspect of the present invention, the second load cell 320 according to the present invention has a ball groove F-1 corresponding to the ball 322 mounted to the ball groove 321 of the second load cell 320 formed thereon. The conveyor frame 100 to which the metal plate F is fixedly coupled may be mounted. The reason why the conveyor frame 100 is loaded on the second load cell 320 by inserting the metal play having the ball groove F-1 formed thereon is that the conveyor frame 100 is easily worn on the ball 322 by the ball 322. This is because it is possible to prevent, and by inserting the metal plate (F) to adjust the separation interval between the load cell and the conveyor frame 100.

According to another aspect of the present invention, the load cell according to the present invention is installed parallel to each other between the conveyor frame 100 and the bad frame 200, it is installed so that the position of the sensing means of the load cell facing each other direction It is done. Referring to FIG. 1C, the center of the first load cell 310 is fixedly coupled to the mechanical center rather than the geometric center of the conveyor frame 100. For example, if the bottom frame of the first load cell 310 is fixedly coupled to the bad frame 200 through the metal plate F on the basis of FIG. 1C, the upper right side of the first log cell is connected to the conveyor frame 100. Fixedly coupled.

The second load cell 320 is fixedly coupled to the lower right side through the metal plate (F) as opposed to the coupling of the first load cell 310, the ball groove 321 in which the ball 322 is mounted is formed on the upper left side, The ball 322 is mounted to the formed ball groove 321. A ball groove F-1 formed in the conveyor frame 100 or a ball groove F-1 formed in the metal plate F is coupled to a position corresponding to the ball 322 mounted to the ball groove 321.

For example, when the installation directions of the first and second load cells 310 and 320 are the same, they may have a measurement value biased to one side. Therefore, the installation direction of the first and second load cells has the advantage of eliminating the imbalance applied to the two load cells when loading and transporting the cargo and at the same time the center of mass of the transported cargo and the load cell upper structure Minimizing away from the center of the instrument contributes to the accuracy of the measurement results.

Figure 3 is a block diagram schematically showing a controller of the automatic cargo weighing apparatus according to an embodiment of the present invention. As shown, the automatic cargo measuring apparatus according to the present invention, the conveyor frame 100 and the bad frame 200 for transferring the loaded cargo according to the operation command input from the user, and the load of the cargo transported by the conveyor Load cells 300-1 and 300-2 for sensing and outputting a measurement signal, and a controller 400 for controlling the overall device. Since the conveyor and the load cell have been described with reference to FIGS. 1A to 1C and FIGS. 2A to 2D, detailed descriptions thereof will be omitted.

The controller 400 controls an operation unit 420 such as a keypad or an input button, a display unit 410 for displaying an operation state of the device and measured weight information, and an overall device of the automatic cargo weighing device according to a user's operation command. And a control unit 430 which receives the measurement signal output from the load cell, calculates the weight of the corresponding cargo and displays it on the display unit 410.

The operation unit 420 is a well-known configuration including a plurality of input buttons. The user may drive the automatic load weighing apparatus through the operation unit 420.

For example, the display unit 410 includes a display device such as a liquid crystal display, and displays an operating state of the device and a weight of a cargo calculated by the controller 430. According to another exemplary embodiment, the operation unit 420 and the display unit 410 may be implemented as a touch panel capable of simultaneously inputting and displaying an operation command.

The control unit 430 calculates the weight of the cargo being transported by the conveyor belt using the measurement signal detected and output by the load cell, and displays the calculated weight through the display unit 410.

According to a characteristic aspect of the present invention, the control unit 430 according to the present invention samples and groups the measured signals output from the load cells at a fixed interval at predetermined time intervals, calculates an average value of the sampling values of each group, and calculates an average value. Minimum standard deviation & Maximum mean for calculating the standard deviation between the sampling values of each group by extracting two groups with the average size among the groups, and calculating the weight of the cargo using the sampling value of the group with the smallest standard deviation It is implemented through an algorithm (hereinafter referred to as 'MDMM algorithm').

Hereinafter, the configuration of the control unit 430 according to the present invention will be described in more detail. The control unit 430 may output a low pass filter 431 for removing noise of a measurement signal detected by the first and second load cells 310 and 320, and a dynamic measurement signal output from the low pass filter 431. A sampling unit 433 for digitally sampling and grouping each time by a predetermined period, and calculating an individual average value of each group sampled by the sampling unit 433, and calculating two groups having the highest value among the calculated average values of the group. By the average calculating unit 435 to extract, the standard deviation calculating unit 437 for calculating the standard deviation of the measurement data of the two groups extracted by the average calculating unit 435, and the standard deviation calculating unit 437 The weight calculation unit 439 selects a group having a small standard deviation through the calculated standard deviation and calculates the weight data.

Cargo weight measurement process of the control unit 430 will be described in more detail with reference to FIG. 4 is a flowchart schematically illustrating a weight calculation process of a control unit according to an exemplary embodiment of the present invention. As shown, when the user loads the load on the conveyor belt, and inputs a drive command of the automatic load weighing device through the operation unit 420, the drive motor of the conveyor is driven while the conveyor belt is driven to transfer the loaded cargo Let's do it.

Meanwhile, the first and second load cells 310 and 320 detect the load generated by the cargo loaded on the conveyor and output the measurement signal to the low pass filter 431 of the controller 430. The low pass filter 431 removes and outputs noise of the measurement signals output from the first and second load cells 310 and 320. The measurement signal output by the low pass filter 431 is dynamic analog data that changes with time.

The control unit 430 composed of digital logic cannot calculate this. Accordingly, the sampling unit 433 of the control unit 430 samples the dynamic analog signals output from the low pass filter 431 into digital data at predetermined intervals and groups them. For example, the sampling unit 433 is sampled at a period of 2 kHZ, and each of the sampled data is output to the average calculation unit 435 by grouping at 1/20 intervals of the time that the cargo is transported by the conveyor for grouping. The average calculator 435 calculates an average value of the data measured for each group, compares the calculated average values, and extracts and outputs two groups having the largest average values.

The standard deviation calculator 437 calculates the standard deviation of the measurement data of the two groups extracted and calculated by the average calculator 435, and the weight calculator 439 is calculated by the standard deviation calculator 437. Through the standard deviation, a group having a small standard deviation is selected to calculate the weight of the cargo by linking the average value of the group with the conveying speed of the conveyor and displaying the calculated weight of the cargo through the display unit 410. .

According to an additional aspect of the present invention, the controller 400 of the automatic cargo weighing apparatus according to the present invention may further include an interface unit for transmitting and receiving the calculated weight information of the cargo with an external device. For example, the interface unit may be connected to a computer or a logistics management system provided in the logistics management system and connected to an external device such as a PDA possessed by the logistics manager to the weight calculator 439 according to a control signal of the controller 430. The weight information of the cargo calculated by this is transmitted. The interface unit 450 is a kind of communication modem. For example, RS-232, RS-485, TCP / IP, and Bluetooth communication methods used in a general network may be used.

Therefore, it can be easily interlocked with the logistics management system without a separate classification process and arrangement work, and has the advantage of computerization.

As described above, the automatic cargo weighing apparatus according to the present invention has an advantage that can be easily used for logistics management by automatically measuring and providing the weight of the cargo moving fast on the conveyor belt.

In addition, by mounting a plurality of balls in point contact with the conveyor frame in the load cell, it is possible to detect only the load acting vertically for all loads to ensure the linearity of the measured value, the measured value changed according to the external environment Has the advantage of reducing the error of.

In addition, by placing the two load cells sensing means installed in the automatic cargo weighing device in the opposite direction to each other, there is an advantage that can solve the imbalance applied to each load cell when loading the cargo.

In addition, by grouping the sampled measurement data, by calculating the group with the largest mean value and the smallest deviation among each group and applying it to the weight calculation, it contributes to the precision of the measurement result and can cope with transient input Has

In addition, by having an interface unit for interfacing the external device and the dimension information, it can be easily interlocked with the logistics management system without a separate classification process and arrangement work, and has the advantage of computerization.

The present invention has been described above with reference to preferred embodiments, but is not limited thereto, and is interpreted by the appended claims, which are intended to cover many modifications that will be apparent to those skilled in the art without departing from the scope of the present invention. Should be done.

Claims (5)

delete In the automatic cargo weighing device, A conveyor frame including a conveyor belt for transferring the loaded cargo and a driving means for driving the conveyor belt; A bad frame installed at a lower end of the conveyor frame to support the conveyor frame;  The center is installed so as to correspond to the mechanical center according to the center of gravity of the conveyor frame, and is provided between the conveyor frame and the bad frame, and outputs a measurement signal according to the weight of the cargo to be transported. A plurality of balls fixedly coupled to the bad frame, the first load cell having the upper other side fixedly coupled to the conveyor frame, and the lower one side fixedly coupled to the bad frame, and transferring only the vertical load applied by the conveyor frame to the upper other side A second load cell in which the ball groove is mounted; A display unit for displaying the weight information of the cargo calculated by the device, and controls the overall device, receives the measurement signal output from the first load cell and the second load cell to calculate the weight of the cargo and display on the display unit A controller including a control unit; Automatic cargo weighing apparatus comprising a. The method of claim 2, wherein the first and second load cells are: Automatic cargo weighing apparatus is installed in parallel to each other, the position fixed to the conveyor frame and the bad frame relative to the mechanical center of the conveyor frame is installed in the opposite direction to each other. The method of claim 2, wherein the control unit: A low pass filter for removing noise of measurement signals sensed and output by the first and second load cells; A sampling unit configured to digitally sample and group the dynamic measurement signal output from the low pass filter by a time divided by a predetermined period; An average calculating unit calculating an individual average value of each of the groups sampled by the sampling unit, and extracting two groups having the highest value among the calculated average values of the groups; A standard deviation calculator for calculating a standard deviation of two groups of measurement data extracted by the average calculator; A weight calculator configured to select a group having a small standard deviation from the standard deviation calculated by the standard deviation calculator and calculate weight data; Automatic cargo weighing apparatus comprising a. delete

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