JPH0783744A - Electronic balance - Google Patents

Abstract

PURPOSE:To obtain an automatic opening/closing device for the weighing chamber door of an electronic balance which can be automatically opened/closed at an aperture after the aperture is once set at a desired value with a simple constitution. CONSTITUTION:The door 4 of a weighing chamber is opened to a desired aperture by actuating a motor 5 with an opening switch 7a. Upon turning on the switch 7a, a timer 12 is actuated, measures the operating time T of the motor 5 required for opening the door 4 to the desired aperture, and stores the time T in the memory 11 of a control section 6. When the switch 7a is turned on thereafter, the timer 12 is simultaneously actuated and a central processing section 10 operates the motor 5 until the set time T elapses. Therefore, the door 4 can be opened to the same aperture when the switch 7a is turned on without making any special operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic scale having a mechanism for automatically opening and closing a weighing chamber door, and more particularly to an electronic scale having a mechanism for automatically opening and closing the weighing chamber door at a desired opening.

[0002]

2. Description of the Related Art An electronic balance represented by an electromagnetic balance type weighing device has a high measurement accuracy. However, in order to guarantee this accuracy, it is necessary to eliminate disturbance, which is a factor of lowering the measurement accuracy, as much as possible. There is. One of the main disturbances is the flow of air around the weighing pan on which the weighing object is placed. For this reason, a means for separating the space surrounding the weighing dish from the outside as a weighing chamber, or arranging a windshield inside the weighing chamber so as to doubly isolate the space is adopted.

From the above viewpoints, various weighing devices have been proposed. For example, when viewed from the outer shape of the weighing chamber, it has a quadrangular shape (Japanese Patent Publication No. 3-9410, Japanese Utility Model Publication 3-11711).
No.) or a cylindrical shape (Jitsuhei 3-2414, Jitsukaihei 4-57727) and the like are proposed. In addition, the windshield drive system is not only manual
No. 57727, Jikken 2-47460, Japanese Fair 3-2
No. 414, Jpn. Pat. Appln. KOKAI Publication No. 3-11711, etc., there are proposed automatic opening and closing by using a motor as a drive device.

In the above-mentioned construction, in the structure for manually opening and closing the door, if the door is opened and closed carelessly, unnecessary vibration is brought to the weighing device, and it takes time for the device to stabilize, or the measurement system becomes unstable. There is a possibility that the device will be adversely affected, for example, it will decrease. For this reason, particularly in highly accurate weighing devices, devices having an automatic opening / closing mechanism in which the door is opened / closed automatically by push button operation etc. are generally well-received rather than manually. There are the following problems because it is premised on full opening and front closing.

That is, when the door is opened and closed to take in and out the weighing object, it is desirable that the opening degree of the door is set to a necessary minimum in order to minimize the influence of the air flow, and the full opening operation is always performed. Therefore, the time required for opening and closing operation becomes long, and there is a problem in terms of speeding up the measurement work. On the other hand, when sequentially measuring objects that have almost the same shape or similar weight, such as the weight of specific parts, the required opening of the door will of course be almost the same. It is much more efficient if the opening / closing operation of the door is automatically performed at a desired opening degree, rather than manually opening and closing the door each time.

[0006]

From the above viewpoint, a method is conceivable in which the open / closed state of the weighing chamber door is detected and the door is automatically opened / closed at a predetermined opening degree. Limit position switches, photo sensors, and other position measurement sensors can be used as the door position detection means.However, since all of these detect only a specific position, the door opening / closing control depends on the number of these sensors. Only the stepwise control can be performed, and it is not always possible to meet the demands of the weighing device user. Further, basically, it is possible to finely set the opening degree by increasing the number of the installed sensors, but it is necessary to connect each sensor and the storage means to each circuit, which complicates the configuration of the apparatus. To do. In addition, these sensors and control units are usually installed inside the weighing device because of their external appearance or the need to protect parts. In this case, if the number of these sensors installed increases, the heat generated by the sensors causes the weighing device to operate. There is also a problem that there is a high risk of impairing the measurement accuracy as described above.

[0007]

SUMMARY OF THE INVENTION The present invention is constructed to solve the above-mentioned problems, and has a relatively simple structure for freely and automatically opening and closing the door of a weighing chamber and setting the opening thereof. It was made possible. That is, the door of the weighing chamber is configured to be automatically opened and closed by the driving means including the electric motor, and the control unit for controlling the automatic opening and closing is provided with means for storing the required amount of door opening and closing as the driving time of the driving means. The electronic scale is characterized in that the door is automatically opened and closed at a desired opening based on the set driving time.

[0008]

When the door is opened to a desired opening by operating the driving means using a push button type switch, the operating time of the driving means during this period is measured as the operating time of the driving means by the time measuring means. The measured time is stored and stored in the storage means. From the next time onward, for example, by simply pressing the open switch, the control unit automatically opens the door to the same opening as the previous time by controlling the drive means based on the stored operation time of the drive means.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a door opening / closing mechanism of a weighing device showing an embodiment of the present invention. In the figure, an arrow 1 indicates a weighing chamber of the weighing device 10, which is formed in a cylindrical shape, and a weighing dish 2 is arranged on the inner floor surface 1 a of the weighing chamber 1. Reference numeral 3 denotes a fixed wall that is vertically fixed to the floor surface 1a of the weighing chamber, and reference numeral 4 denotes a door that is a rotating wall surface that is arranged substantially concentrically with the fixed wall 3. By rotating this door 4, the weighing chamber 1 is opened,
Alternatively, the weighing chamber 1 is engaged with the fixed wall 3 to form a closed space.

Reference numeral 5 is an electric motor (hereinafter simply referred to as a motor) as a driving means for rotating (opening / closing) the door 4, 6 is a control section for controlling the motor 5, and 7 is connected to the control section 6. The input unit 9 is a sensor that detects the closed position of the door 4 (hereinafter referred to as "closed position sensor").

The configuration of the control unit 6 among the above units will be described first. Reference numeral 10 is a central processing unit that performs a central function of the control unit 6, 11 is a memory that stores various data, and 12
Is a time measuring means (hereinafter referred to as “timer”) for measuring the operating time of the motor 5, and the measured value by the timer 12 is stored in the memory 11 via the central processing unit 10.

Next, the input section 7 is connected to the control section 6 and is usually formed as a part of the operation panel of the electronic scale in which the present apparatus is incorporated. Reference numeral 7a is an open switch for performing the opening operation of the door 4, 7b is a close switch for performing the closing operation, 7c is a cancel switch for erasing the data stored in the memory 11 of the control unit 6, 7
Reference numeral d denotes a selection switch, which selects the data stored in the memory 11, that is, the opening of the door 4, and deletes the data when the cancel switch 7c deletes the data. A switch used to select data.

Next, the operating state of this apparatus will be described with reference to FIG. 1 and a flow chart. Here, the present device basically stores the initially set opening degree of the door as the operating time of the driving means,
After that, the door is automatically opened and closed at the opening degree set based on the stored time data. Therefore, it is necessary to first set a desired door opening.

FIG. 2 shows an example of setting the door opening. First, the open switch 7a of the input unit 7 shown in FIG. 1 is pressed, whereby the central processing unit 10 of the control unit 6 issues an operation signal to the motor 5 and simultaneously turns on the timer 12. As a result, the motor 5 starts operating (A2) and at the same time, the timer 12
Starts measuring the motor operating time (A3). When the door 4 reaches the desired opening, let go of the open switch 7a,
The switch 7a is turned off, the timer 12 is stopped by this off signal (A4), the timer 12 stops time measurement (A5), and the motor 5 also stops (A6). The time T from the start to the stop of the motor is stored in the memory of the control unit 6 (A7), and the motor 5 operates based on this time T as described later.

FIG. 3 shows another method for setting the door opening. Figure 2
The method shown in (1) is based on the premise that the door is opened by using the driving device, whereas in this case, the setting method when the door is first opened manually is shown. That is, the closed door 4 is manually opened (B1), and when the desired opening is reached, the manual opening operation is stopped (B2). In this state, the closing switch 7b of the input unit 7 is turned on, and at the same time, the timer 12 is started (B3), the motor 5 is operated (B4), and the door 4 is operated to be closed. At the same time, the measurement of the time required for the closing operation is started. When the door 4 reaches the closed position, a signal is issued by the closed position sensor 9. Therefore, the presence or absence of this signal is judged (B5), the door closing operation is continued until the closed position signal is issued, and the time is measured (B6). ) Is performed, and the motor 5 is stopped by the close signal when the closed position is reached (B7).
To do. Along with this, the timer 12 is also stopped and the time T
Is stored (B8). That is, in this case, the time for closing the door 4 is measured, and this measured time is used as a reference for subsequent door opening / closing operations.

In each of the above flows, it is premised that the opening of the door is set to one, and once the opening is set to a predetermined value, the automatic opening and closing is performed at this opening thereafter. By way of example, it is also possible to set some kinds of door openings in advance in addition to this and automatically open and close them at a desired opening. In this case, means for putting the device in the storage mode, such as a storage mode switch, is arranged in the input section of FIG.
In this state, using the method shown in FIG. 2 or 3, the operation time of the door opening / closing mechanism is measured and stored for each desired opening of the door. As a result, after that, a desired opening is selected from the stored door openings to open and close the door.

FIG. 4 shows an example of a door opening / closing operation (operation) when one door opening is set. First open switch 7
The timer 12 is also started by turning on a (C
1) When the open switch is turned on, the motor 5 starts operating (C2), and the door 4 is opened. During this time timer 1
2, the central processing unit 10 compares the set time T stored in the memory 11 with the count time and judges whether or not the time T has been reached (C3). If so, the motor 5 is stopped (C4). Since the position of the door stopped at the set time T corresponds to the door opening preset with time as a parameter,
The door 4 will stop at a preset opening. In this case, even if the open switch 7a is pressed once, the door 4 automatically opens up to a predetermined opening even if the switch is released, and on the contrary, the open switch 7a is continuously pressed unless a cancel switch or the like described later is operated. Also, when the opening degree reaches a preset value, the motor 5 stops and does not open any more.

When the work of measuring the weight of the object in the weighing device is completed, the closing switch 7b of the input unit 7 is turned on, and at the same time, the timer 12 is started (C5),
The motor 5 operates in the reverse direction (C6) to close the door 4.
During this time, the timer 12 counts the time of the closing operation, the central processing unit 10 compares the time T used for the opening operation with the time of the closing operation (C7), and stops the motor 5 when the time T elapses (C8). To do. Since the time required for the opening operation and the time required for the closing operation are the same, the door 4 is closed and the weighing chamber 1 is closed.

It is of course possible to stop the closing operation by the output signal of the closed position sensor 9 regardless of the time T. Further, as described above, by rotating the motor 5 in the reverse direction, the door 4 is rotated in the opposite direction to the opening operation to return to the original position and the closing operation is performed. It is also possible to open and close this. In this case, in addition to stopping the closing operation by the signal from the closed position sensor 9, it is possible to use the measurement time T without using the closed position sensor 9. That is, when the door is rotated in a certain direction, the time from fully closed to fully open can be measured in advance. Therefore, this time T1 is stored in the memory 11, and the difference T2 between this time T1 and the set time T remains. Therefore, if the central processing unit 11 controls the motor 5 to stop when the time T2 elapses after the door closing operation starts, the central processing unit 11 rotates in the same direction without using the closed position sensor 9. The door 4 can be opened and closed with.

Next, the case where a plurality of door openings are set will be described. As described above, by setting the device in the storage mode, the memory 11 of the control unit 6 is set for each desired opening of the door.
It is possible to store the operation time of the door opening / closing mechanism in. For example, there are multiple types of objects to be measured, one of which has a small mass but a large volume and therefore requires a large opening of the door, and the other one is a powder having a small bulk, Since it is easy to be scattered by the wind, it is necessary to reduce the opening of the door and take it in and out, and when these are appropriately replaced and measured, the desired opening is set using the selection switch 7d of the input unit. For example, if one of the selection switches 7d is set to a large opening and 2 is set to a small opening, the selection switch 7d's 1 is pressed in the case of the bulky object. As a result, the central processing unit 10 of the control unit 6 retrieves the data corresponding to the large opening degree out of the data stored in the memory 11 to perform the door opening / closing control, and conversely, when the opening degree is small, the opening degree is small. The data corresponding to is retrieved and controlled. Therefore, in this case, even if the type of the measurement target changes, the door can be automatically opened and closed at the optimum opening for the measurement target by appropriately operating the selection switch.

On the other hand, the data stored in the memory 11 can be erased by using the cancel switch 7c. In this case, when a plurality of data are stored in the memory 11, it is possible to select specific data by using the selection switch 7d and erase only the selected data.

[0023]

As described in detail above, the present invention is constructed so that the door of the weighing chamber is automatically opened and closed by the drive means.
The control unit for opening and closing the door is provided with means for storing the required amount of opening and closing of the door for the operating time of the drive means, and is configured so that the opening and closing operation of the door can be automatically performed at a desired opening based on the stored operating time. Therefore, the opening and closing of the door can be set to a desired opening completely steplessly, and since the control is performed only for the driving means that opens and closes the door, the configuration is relatively simple. The reliability of the device is high, and the device can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a door opening / closing control mechanism showing an embodiment of the present invention.

FIG. 2 is a flow chart showing an example of measurement of an operation amount of a door opening / closing drive means.

FIG. 3 is a flowchart showing another example of measurement of the operation amount of the door opening / closing drive means.

FIG. 4 is a flowchart showing an example of an operating state of a door opening / closing mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Weighing chamber 4 Door 5 Motor (driving means for door opening / closing) 6 Control section 7 Input section 7a Open switch 7b Close switch 7c Cancel switch 7d Select switch 9 Closed position sensor 10 Central processing section 11 Memory 12 Timer 15 Weighing device

Claims (1)

[Claims] 1. A weighing device having a weighing chamber configured to open and close a door by a driving means, wherein a time measuring means for measuring an operating time of the driving means corresponding to an opening of the door, and the time measuring means By having a means for storing the measured operating time of the driving means and a control means for operating the driving means in correspondence with the stored operating time of the driving means, the weighing chamber of the weighing chamber can be opened at a preset opening degree. An electronic scale characterized by automatically opening and closing the door.