JP7628376B2 - Fixed quantity supply device - Google Patents

Description

The present invention relates to a quantitative supply device that supplies a quantitative amount of a measured object, and in particular to a quantitative supply device that is suitable for supplying a quantitative amount of powder or granular material.

For example, Patent Document 1 discloses a cut gate for an automatic supply device as a fixed quantity supply device. In this patent document, a cut gate (electric shutter) that can be opened and closed is installed at the outlet of a hopper that contains a large amount of objects to be weighed, a weighing bucket is placed below the outlet, and a predetermined amount of objects to be weighed is placed in the weighing bucket by controlling the opening of the cut gate based on the weight of the objects to be weighed in the weighing bucket detected by a load cell, and a predetermined amount of objects to be weighed is supplied from the weighing bucket.

Japanese Utility Model Application Publication No. 62-18627

The above-mentioned Patent Document 1 employs a servo mechanism that uses a position detector to detect the opening of the cut gate and feedback-controls the servo motor that drives the cut gate.

The problem with such servo mechanisms is that they are complicated to configure and expensive to use.

The present invention was developed with this in mind, and its main objective is to reduce the cost of the constant-volume supply device.

In order to achieve the above objective, the present invention is configured as follows:

(1) A quantitative supply device according to the present invention is a quantitative supply device comprising a storage hopper which stores objects to be weighed and discharges the objects from a discharge outlet at a lower portion thereof and feeds the objects into a weighing hopper, the weighing hopper which stores the objects to be weighed fed from the storage hopper and weighs them, and a control means which controls the amount of the objects to be weighed fed from the storage hopper into the weighing hopper,
The weighing hopper is provided with a cut gate provided at the discharge outlet of the storage hopper and a stepping motor for driving the cut gate, and the control means controls the amount of the objects to be weighed that are discharged from the storage hopper to the weighing hopper by controlling the stepping motor to adjust the opening of the cut gate, and the control means switches between a first input stage in which the opening of the cut gate is maintained at a first set opening and the objects to be weighed are input until the input weight of the objects to be weighed that are input from the storage hopper to the weighing hopper becomes a first set weight, a second input stage in which the opening of the cut gate is reduced from the first set opening to a second set opening over a predetermined set time while controlling the input amount based on a set time, and the objects to be weighed are input while the opening of the cut gate is reduced from the first set opening to a second set opening over a predetermined set time, and a third input stage in which the opening of the cut gate is maintained at the second set opening and the objects to be weighed are input until the input weight of the objects to be weighed becomes a second set weight that is larger than the first set weight.

In the quantitative supply device according to the present invention, the cut gate installed at the discharge outlet of the storage hopper is driven by a stepping motor, which simplifies the configuration and reduces costs compared to conventional examples in which the cut gate is driven by a servo mechanism.

When the cut gate is driven by a stepping motor, which has a smaller output torque than a servo motor, when the opening of the cut gate is switched to feed the objects to be weighed into the weighing hopper, a wavy vibration component may be generated in the weight of the objects to be weighed that are fed into the weighing hopper and weighed due to factors such as the difference in the amount fed before and after the switch.

According to the present invention, in the second feeding stage, which is transitioned from the first feeding stage in which the objects to be weighed are fed at a relatively large first set opening, the opening of the cut gate is reduced from the first set opening to the second set opening over a pre-set time while the objects to be weighed are fed, and this is done by controlling the feed amount based on a set time. Therefore, unlike the case where the opening of the cut gate is controlled based on the feed weight of the objects to be weighed fed from the storage hopper to the weighing hopper, even if the feed weight of the objects to be weighed fed from the storage hopper to the weighing hopper contains vibration components, it is not affected, and highly accurate weighing is possible.

(2) In a preferred embodiment of the present invention, the control means drives the stepping motor in microsteps.

In this embodiment, the stepping motor can be rotated at fine step angles using microstep drive, reducing vibration and enabling highly accurate weighing.

(3) In one embodiment of the present invention, the control means can selectively switch to input amount control based on input weight in the second input stage, instead of input amount control based on the set time, in which the objects to be weighed are input while decreasing the opening of the cut gate based on the input weight of the objects to be weighed input into the weighing hopper and weighed, and in the input amount control based on the input weight, the control means inputs the objects to be weighed while decreasing the opening of the cut gate from the first set opening until the input weight of the objects to be weighed becomes a third set weight that is smaller than the second set weight.

In this embodiment, in the second input stage, instead of input amount control based on a set time, it is possible to select input amount control based on input weight, in which the items to be weighed are input while reducing the opening of the cut gate based on the input weight of the items to be weighed. Therefore, for example, depending on the properties of the items to be weighed and the size of the set opening, it is possible to select either input amount control based on a set time or input amount control based on input weight.

(4) In a preferred embodiment of the present invention, in the feed amount control based on the set time in the second feed stage, the control means drives the stepping motor at a constant speed so that the opening of the cut gate changes from the first set opening to the second set opening during the set time.

In this embodiment, the stepping motor is driven at a constant speed, so that the opening of the cut gate can be changed from the first set opening to the second set opening in a set time.

(5) In another embodiment of the present invention, the control means includes a setting display unit on which the set time, the first set weight, the second set weight, the first set opening, and the second set opening are set and the set contents are displayed.

In this embodiment, the settings required for switching between each input stage can be made by operating the setting display unit.

(6) In yet another embodiment of the present invention, the stepping motor parameters for reducing the opening of the cut gate from the first set opening to the second set opening in the input amount control based on the set time in the second input stage are set on the setting display unit, and the setting contents are displayed.

In this embodiment, the stepping motor parameters required to adjust the opening of the cut gate for input amount control based on the set time can be set by operating the setting display unit.

According to the present invention, the cut gate installed at the discharge outlet of the storage hopper is driven by a stepping motor, so that a fixed amount of the material to be weighed can be supplied with a simple and inexpensive configuration without using a servo mechanism.

Furthermore, in the second feeding stage, the opening of the cut gate is reduced from the first set opening to the second set opening over a pre-set time while feeding the objects to be weighed, and feeding amount control is performed based on a set time. This enables highly accurate weighing without being affected by vibration components contained in the weight of the objects to be weighed fed from the storage hopper to the weighing hopper, as is the case when the opening of the cut gate is controlled based on the weight of the objects to be weighed fed from the storage hopper to the weighing hopper.

FIG. 1 is a schematic diagram of a constant volume supply device according to an embodiment of the present invention. Figure 2 shows an example of the progression of large, medium and small inputs over time to explain input amount control based on a set time, where Figure 2(a) shows the input weight of the object to be weighed in the weighing hopper, Figure 2(b) shows the opening degree of the cut gate, and Figure 2(c) shows the opening degree of the discharge gate. Figure 3 shows an example of the progression of large, medium and small inputs over time to explain input amount control based on input weight, where Figure 3(a) shows the input weight of the objects to be weighed in the weighing hopper, Figure 3(b) shows the opening degree of the cut gate, and Figure 3(c) shows the opening degree of the discharge gate. FIG. 4 is a diagram showing the first setting display screen. FIG. 5 is a diagram showing the second setting display screen. FIG. 6 is a flow chart illustrating the operation. FIG. 7 is a flow chart illustrating the operation.

The following describes in detail an embodiment of the present invention with reference to the drawings.

Figure 1 is a schematic diagram of a constant volume supply device according to one embodiment of the present invention.

The quantitative supply device 1 of this embodiment is suitable for supplying a specified amount of powdered or granular material such as resin pellets, polished rice, or feed.

This quantitative supply device 1 is equipped with a storage hopper 3 that contains powdered or granular objects 2 to be weighed, and a weighing hopper 4 that is disposed below the storage hopper 3 and into which the objects 2 to be weighed discharged from the storage hopper 3 are fed.

The objects to be weighed 2 are constantly dropped into the rectangular cylindrical storage hopper 3 via a supply chute from a large storage hopper above (not shown). A cut gate 5 is provided at the discharge outlet at the bottom of the storage hopper 3 so that it can rotate forward and backward around a horizontal fulcrum 5a. By rotating this cut gate 5 to adjust the opening of the discharge outlet at the bottom of the storage hopper 3, the amount of objects to be weighed 2 discharged from the storage hopper 3 and fed into the weighing hopper 4 is controlled.

In this embodiment, in order to simplify the configuration and reduce costs compared to conventional examples that use a servo mechanism, the cut gate 5 is driven to rotate by a cut gate stepping motor 10 via a link mechanism (not shown).

Figure 1 shows the weighing hopper 4 in a state where no objects 2 to be weighed have been put in, i.e., the cut gate 5 is closed, and also shows, by imaginary lines, the cut gate 5 rotating counterclockwise around the horizontal fulcrum 5a, so that the objects 2 to be weighed are put in the weighing hopper 4.

The weighing hopper 4 is provided with a pair of discharge gates 4a, 4b at its bottom that open and close simultaneously. When the pair of discharge gates 4a, 4b are closed, the weighing hopper 4 stores the objects to be weighed that are input from the storage hopper 3, and by opening the discharge gates 4a, 4b, a predetermined amount of the stored objects to be weighed 2 can be discharged downward. The discharge gates 4a, 4b are driven to open and close by a discharge gate stepping motor 11 via a link mechanism (not shown).

The weighing hopper 4 is equipped with a load cell 6 as a load sensor that measures the input weight, which is the weight of the objects to be weighed that are discharged from the storage hopper 3 and input into the weighing hopper 4. The load signal from this load cell 6 is input to the control unit 7 of the control means 15. The control means 15 performs various settings such as the set time, set weight, set opening, and motor parameters described below, and is equipped with a setting display unit 8 that displays the settings. This setting display unit 8 is composed of, for example, a touch panel, and is connected to the control unit 7. This control unit 7 has a built-in timer function that measures the set time, etc.

The control unit 7 controls the cut gate stepping motor 10 via the first driver 9 to adjust the opening of the cut gate 5 rotated by the stepping motor 10, thereby controlling the amount of weighed objects 2 fed from the storage hopper 3 to the weighing hopper 4.

The larger the opening of the cut gate 5, the larger the amount of the objects 2 to be weighed that is fed into the weighing hopper 4, and the smaller the opening of the cut gate 5, the smaller the amount of the objects 2 to be weighed that is fed into the weighing hopper 4. When the cut gate 5 is closed, the feeding of the objects 2 to be weighed from the storage hopper 3 into the weighing hopper 4 is stopped.

The control unit 7 controls the discharge gate stepping motor 11 via the second driver 12 to control the opening and closing of the discharge gates 4a and 4b of the weighing hopper 4. When the weight of the objects 2 to be weighed fed into the weighing hopper 4 reaches a predetermined amount, the control unit 7 opens the discharge gates 4a and 4b to discharge the predetermined amount of the objects 2 to be weighed.

In this embodiment, the control unit 7 controls the amount of weighed objects 2 fed from the storage hopper 3 to the weighing hopper 4 in three broad steps.

That is, when the objects 2 to be weighed are first loaded from the storage hopper 3 into the weighing hopper 4, the load is switched between three stages: a large load as the first loading stage, in which the opening of the cut gate 5 is set to a relatively large opening and the objects 2 to be weighed are loaded into the weighing hopper 4 in a large load; a medium load as the second loading stage, in which the opening of the cut gate 5 is reduced and the objects 2 to be weighed are loaded into the weighing hopper 4 in a medium load; and a small load as the third loading stage, in which the objects 2 to be weighed are loaded into the weighing hopper 4 in a small load while keeping the opening of the cut gate 5 reduced during the medium load.

In this embodiment, as described above, in order to simplify the configuration and reduce costs, the cut gate 5 is driven by a cut gate stepping motor 10 without using a servo mechanism.

However, with a stepping motor, which has a smaller output torque and a coarse step angle than a servo motor, when the opening of the cut gate 5 is switched to feed the objects 2 to the weighing hopper 4, a wavy vibration component may be generated in the weight of the objects fed into the weighing hopper 4 and weighed due to the difference in the amount fed before and after the switch and the properties of the objects.

For this reason, in this embodiment, even if the weight of the objects to be weighed that are put into the weighing hopper 4 contains vibration components, the weighing can be performed with high accuracy without being affected by the vibration components, as follows.

In other words, in the medium charge following a large charge in which a large amount of the objects 2 to be weighed is charged into the weighing hopper 4, the amount of the objects 2 to be weighed charged from the storage hopper 3 into the weighing hopper 4 can be controlled based on a set time.

This input amount control based on the set time is a control in which the objects to be weighed 2 are input into the weighing hopper 4 while decreasing the opening of the cut gate 5 from a first preset opening to a second preset opening over a preset time.

Figure 2 shows an example of the progression of large input (large input), medium input (medium input) and small input (small input) over time to explain the input amount control based on this set time, where Figure 2(a) shows the input weight Wx, which is the measured weight of the object 2 to be weighed weighed in the weighing hopper 4, Figure 2(b) shows the opening degree of the cut gate 5, and Figure 2(c) shows the opening degree of the discharge gates 4a and 4b.

In this embodiment, as shown in FIG. 2(b), the cut gate 5 starts to open from time t0 and is maintained at the first set opening AP1, which is the preset opening for large input (large input opening), and the objects 2 to be weighed are input from the storage hopper 3 to the weighing hopper 4, so that the input weight Wx of the objects 2 to be weighed in the weighing hopper 4 increases, as shown in FIG. 2(a).

This first set opening AP1 is set to a relatively large value, and in the case of large loading, a relatively large amount of the objects 2 to be weighed is loaded from the storage hopper 3 to the weighing hopper 4.

When the weight Wx of the objects 2 to be weighed that are fed into the weighing hopper 4 by this large feed reaches a first set weight W1, which is a preset large feed amount, as shown in FIG. 2(a), at time t1, the feed switches from large feed to medium feed.

During this medium input, input amount control based on a set time is performed. In input amount control based on a set time, the opening of the cut gate 5 is reduced from the above-mentioned first set opening (large input opening) AP1 to a second set opening AP2, which is a preset small input opening (small input opening), at a set time T1, as shown in FIG. 2(b). At this time, the cut gate stepping motor 10 is driven at a constant speed.

The constant speed of the cut gate stepping motor 10 is calculated from the first set opening AP1 for large input, the second set opening AP2 for small input, and the set time T1 for medium input, which are preset by the setting display unit 8, as described below.

In this input amount control based on the set time, at time t1, medium input is started at the first set opening AP1 for large input, and at time t2, when the set time T1 for medium input has elapsed, the opening of the cut gate 5 becomes the second set opening AP2 for small input. As a result, in medium input, as the opening of the cut gate 5 decreases over time, the rate of increase in the input weight Wx of the objects 2 to be weighed also decreases, as shown in Figure 2(a).

Then, when the set time T1 for medium input has elapsed and the opening of the cut gate 5 reaches the second set opening AP2, which is the opening for small input, at time t2, the input switches from medium input to small input, and during small input, the opening of the cut gate 5 is maintained at the second set opening AP2, as shown in FIG. 2(b).

As a result, the amount of weighed object 2 poured in becomes a relatively small constant value corresponding to the second set opening AP2, and the rate of increase in the poured weight Wx further decreases, as shown in Figure 2(a).

Even after the cut gate 5 is closed, the input weight Wx continues to increase by the drop amount Wd, which corresponds to the drop from the storage hopper 3 to the weighing hopper 4.

For this reason, in the case of small loading, as shown in FIG. 2(a), when the loading weight Wx reaches the second set weight W2 (=Wp-Wd), which is the weight obtained by subtracting the drop difference Wd from the predetermined amount Wp, which is the target weight, at time t3, the opening of the cut gate 5 is reduced and closed to stop the loading of the objects 2 to be weighed.

Finally, as shown in FIG. 2(a), at time t4 when the stabilization time T2 measured by the stabilization timer has elapsed, the input weight Wx converges to a value close to the predetermined amount Wp, which is the target weight value. When this predetermined amount Wp is obtained, the discharge gates 4a and 4b of the weighing hopper 4 are opened and closed for the discharge time T3 measured by the discharge timer, as shown in FIG. 2(c), and the predetermined amount of the objects 2 to be weighed that were supplied to the weighing hopper 4 is discharged from the weighing hopper 4. This completes one fixed-quantity supply.

As described above, in the intermediate loading mode, the amount of the objects 2 to be weighed loaded from the storage hopper 3 into the weighing hopper 4 is controlled based on a set time without using the loading weight Wx of the objects 2 to be loaded into the weighing hopper 4 and weighed. Therefore, even if a vibration component occurs in the loading weight Wx of the objects 2 to be loaded into the weighing hopper 4 and weighed due to the difference in the loading amount before and after the opening of the cut gate 5 is switched or the properties of the objects to be weighed, the measurement can be performed with high accuracy without being affected by the vibration component.

Furthermore, in this embodiment, the control means 15 drives the cut gate stepping motor 10 in microsteps so that the cut gate stepping motor 10 can be rotated at fine step angles. It is preferable to make the basic step angle finer, about 1/4 to 1/8, and in this embodiment, for example, one step of 1.8° is rotated at 1/8 of that, that is, 0.225°. By driving the cut gate stepping motor 10 in this way in microsteps, vibrations can be reduced and measurement can be performed with even higher accuracy.

In cases where a vibration component occurs in the input weight Wx of the objects to be weighed that are input into the weighing hopper 4 and weighed, the input amount control based on the set time described above allows for appropriate control without being affected by the vibration component of the input weight Wx. However, depending on, for example, the properties of the objects to be weighed and the size of the set opening, it may be preferable to control the input amount based on the input weight Wx rather than the set time, since no vibration component occurs in the input weight Wx.

In this embodiment, instead of the input amount control based on the set time described above, the input amount control based on the input weight Wx of the object to be weighed is switched to and selected, in which the opening of the cut gate 5 is reduced while the object to be weighed 2 is input, based on the input weight Wx of the object to be weighed. This switching selection can be performed by the setting operation of the setting display unit 8.

This control based on the input weight Wx is a control that inputs the objects 2 to be weighed into the weighing hopper 4 while reducing the opening of the cut gate 5 based on the input weight Wx, which is the measured weight of the objects 2 to be weighed that are input from the storage hopper 3 to the weighing hopper 4 and weighed in the weighing hopper 4.

Figure 3 shows an example of the progress over time of large input (large input), medium input (medium input) and small input (small input) to explain input amount control based on this input weight Wx. Figure 3(a) shows the input weight Wx, which is the measured weight of the objects 2 to be weighed measured by the weighing hopper 4, Figure 3(b) shows the opening degree of the cut gate 5, and Figure 3(c) shows the opening degree of the discharge gates 4a and 4b.

After the large and small inputs, the process is the same as in Figure 2 above, so we will explain medium input, which controls the input amount based on the input weight Wx.

When the input weight Wx of the objects 2 to be weighed that have been input into the weighing hopper 3 by large input and weighed reaches the first set weight W1, as shown in FIG. 3(a), at time t1, the input switches from large input to medium input.

During this intermediate loading, the opening degree AP of the cut gate 5 is reduced as the loading weight Wx measured by the weighing hopper 4 increases. Specifically, the opening degree AP of the cut gate 5 is controlled to an opening degree calculated based on the following equation 1.

この数１において、Ｗ３は、予め設定された第３設定重量であり、この第３設定重量Ｗ３は、上記の第１設定重量Ｗ１より大きく、小投入の投入を停止する上記の第２設定重量Ｗ２(＝Ｗｐ－Ｗｄ)より小さい（Ｗ１＜Ｗ３＜Ｗ２）。また、冪指数αは、０．３≦α≦０．７を満足する任意の値であり、この実施形態では、α＝０．５である。なお、ＡＰ１及びＡＰ２は、上記の大投入の第１設定開度ＡＰ１及び小投入の第２設定開度ＡＰ２である。

In this equation 1, W3 is a third preset weight, which is greater than the first preset weight W1 and less than the second preset weight W2 (=Wp-Wd) at which small input is stopped (W1<W3<W2). The exponent α is an arbitrary value that satisfies 0.3≦α≦0.7, and in this embodiment, α=0.5. AP1 and AP2 are the first preset opening AP1 for large input and the second preset opening AP2 for small input.

During intermediate loading, where loading amount control is performed based on this loading weight Wx, as the opening AP of the cut gate 5 decreases over time t in accordance with the above equation 1, the loading amount of the objects 2 to be weighed is gradually reduced, and the rate at which the loading weight Wx increases also gradually decreases.

Then, when the input weight Wx reaches the third set weight W3 (Wx = W3), at time t2, the input switches from medium to small.

The cut gate opening AP at time t2 when the medium input is switched to the small input is the second set opening AP2, as can be seen from the above formula 1. The rest is the same as in Figure 2 above.

Next, we will explain the setting operations required to control the large, medium, and small inputs mentioned above.

Figure 4 shows a first setting display screen, which is an example of a setting display screen by the setting display unit 8, and Figure 5 shows a second setting display screen.

As shown in Figure 4, the above-mentioned predetermined amount Wp, which is the target weight of the objects 2 to be weighed discharged from the weighing hopper 4, the upper weight limit, the lower weight limit, the above-mentioned stability timer time, the discharge timer time, and the waiting time after discharge are set.

Also, as shown in FIG. 5, in the control based on the input weight Wx, the predetermined amount before switching from medium input to small input, which is the third set weight W3, the large input amount, which is the first set weight W1, which switches from large input to medium input, the drop amount Wd required to calculate the second set weight W2 (=Wp-Wd), which is the weight at which small input is stopped, the large input opening, which is the first set opening AP1, the small input opening, which is the second set opening AP2, the input amount control based on the set time or the input amount control based on the input weight, and the medium input time, which is the set time T1, are set when input amount control based on the set time is selected.

When "0.00" is set for the mid-throw time, input amount control based on the input weight is selected, and when a value other than "0.00" is set, input amount control based on the set time is selected and the mid-throw time (set time T1) is set to the set value.

Also, as shown in FIG. 5, in order to control the drive of the cut gate stepping motor 10, motor parameters such as the motor start speed, end speed, motor maximum speed, motor acceleration, and motor deceleration offset are set for large input and small input.

Here, we will explain how to calculate the speed of the cut gate stepping motor 10 when controlling the input amount based on the above set time.

In this input amount control based on the set time, the required speed of the cut gate stepping motor 10 is calculated from the first set opening AP1, which is the large opening, the second set opening AP2, which is the small opening, and the medium opening time, which is the set time T1.

The speed V (Hz) of the cut gate stepping motor 10 is calculated by the following formula, assuming that the number of pulses A and B for the first set opening AP1 and the second set opening AP2 are set to a medium opening time T1.

V=(A-B)/T1
For example, in the example of Figure 5, one rotation is 360° and normally one step is 1.8°, but as described above, by using microstep driving, one step is divided into 1/8, so the number of motor drive pulses per rotation is 1600 pls (= 360 * 8 / 1.8).

If the full opening of the cut gate 5 is set to, for example, 50%, the number of pulses when the cut gate 5 is fully open will be 800 pls.

If the first set opening AP1, which is the large opening, is set to, for example, 29% as shown in FIG. 5, the number of pulses A of the first set opening AP1 is as follows:
A=800×029=232
In addition, if the second set opening AP2, which is the small throw opening, is set to, for example, 14% as shown in FIG.
The number of pulses B of the second set opening AP2 is
B=800×0.14=112
It becomes.

If the set time T1, which is the intermediate throw time, is set to, for example, 0.5 sec, the motor speed V of the cut gate stepping motor 10 is
The motor speed V is (232-112)/0.5=240 (Hz), and the drive settings of the cut gate stepping motor 10 are as follows:

Motor start and end speed 240 (Hz)
Maximum motor speed: 240 (Hz)
Motor acceleration 0 (Hz)
Motor deceleration offset 0 step
By driving the cut gate stepping motor 10 at this calculated speed, the opening degree of the cut gate 5 is reduced from the first set opening degree AP1 to the second set opening degree AP2 in the set time T1.

Figures 6 and 7 are flowcharts explaining the operation of the above embodiment.

First, in FIG. 6, input is started (step S1), and the input sequence process of FIG. 7 described later is started (step S2), and it is determined whether there is a sequence reset request such as an emergency stop (step S3). If there is no sequence reset request, it is determined whether an alarm is generated, for example, due to the input weight exceeding the weight upper limit (step S4). If no alarm is generated, it is determined whether the sequence is completed (step S5). If it is completed, it transitions to a 10 ms sleep mode (step S6) since it is a sequence that is started every 10 ms. If there is no sequence reset request in step S3 above, and if there is no alarm in step S4, it transitions to a sequence reset process (step S7), and then transitions to step S6. If the sequence is not completed in step S5 above, it is determined whether there is a step progress (step S8), and if there is a step progress, it returns to step S2, and if there is no step progress, it transitions to a 10 ms sleep mode (step S9).

In the input sequence process, as shown in FIG. 7, it is determined whether input has started or whether the input amount has reached a target (step S10).
It is determined whether a large input, a medium input, a small input, or the input is complete.

When input begins or when the input amount reaches the target, the parameters are rewritten to parameters corresponding to the next input (step S15). Specifically, the motor parameters such as the input opening, start and end speeds, maximum speed, acceleration, and deceleration offset are rewritten to parameters corresponding to the next input.

In step S10 above, if the injection has not started and the injection amount has not reached the target, it is determined whether or not medium injection is in progress (step S11), and if medium injection is not in progress, it is determined that large injection or small injection is in progress and the current opening is maintained (step S16).

When the medium injection is selected in step S11, it is determined whether or not the medium injection time is set (step S12). If the medium injection time is not set, the opening degree is updated to an opening degree corresponding to the injection weight (step S13). If the medium injection time is set, the opening degree is updated to a value based on the injection time (step S14).

As described above, according to this embodiment, the cut gate 5 provided at the discharge outlet of the storage hopper 3 is driven by the cut gate stepping motor 10, so that a fixed amount of the material to be weighed can be supplied with a simple and inexpensive configuration without using a servo mechanism.

Furthermore, in the medium loading mode, the opening of the cut gate 5 is reduced from the first set opening AP1 to the second set opening AP2 over a preset time while the weighed objects are being loaded, and the loading amount is controlled based on a set time. This allows for highly accurate weighing without being affected by vibration components contained in the weight of the weighed objects loaded from the storage hopper 3 to the weighing hopper 4, as is the case when the opening of the cut gate 5 is controlled based on the loading weight of the weighed objects loaded from the storage hopper 3 to the weighing hopper 4.

In the above embodiment, the discharge gates 4a and 4b of the weighing hopper 4 are opened and closed by a stepping motor, but they may also be opened and closed by an air cylinder or the like.

REFERENCE SIGNS LIST 1 Fixed quantity supply device 3 Storage hopper 4 Weighing hopper 5 Cut gate 6 Load cell 7 Control unit 8 Setting display unit 10 Cut gate stepping motor 15 Control means

Claims (6)

A quantitative supply device comprising: a storage hopper for storing objects to be weighed and discharging the objects from a discharge port at a lower portion thereof and feeding the objects into a weighing hopper; the weighing hopper for storing and weighing the objects fed from the storage hopper; and a control means for controlling an amount of the objects to be weighed fed from the storage hopper into the weighing hopper,
A cut gate is provided at the discharge port of the storage hopper, and a stepping motor is provided to drive the cut gate.
the control means controls the stepping motor to adjust the opening degree of the cut gate, thereby controlling the amount of the objects to be weighed that is fed from the storage hopper to the weighing hopper;
the control means switches between a first input stage in which the opening of the cut gate is maintained at a first set opening and the objects to be weighed are input from the storage hopper to the weighing hopper until the input weight of the objects to be weighed reaches a first set weight, a second input stage in which the opening of the cut gate is reduced from the first set opening to a second set opening over a preset time period while controlling the input amount based on a set time, and a third input stage in which the opening of the cut gate is maintained at the second set opening and the objects to be weighed are input until the input weight of the objects to be weighed reaches a second set weight that is larger than the first set weight.
A quantitative supply device characterized by: The control means drives the stepping motor in micro steps.
The constant rate supply device according to claim 1. the control means is capable of selectively switching, in the second feeding stage, to feeding amount control based on a feeding weight, in which the objects to be weighed are fed into the weighing hopper while reducing the opening degree of the cut gate, based on the feeding weight of the objects to be weighed, instead of the feeding amount control based on the set time,
In the input amount control based on the input weight, the control means inputs the objects to be weighed while decreasing the opening degree of the cut gate from the first set opening degree until the input weight of the objects to be weighed becomes a third set weight which is smaller than the second set weight.
3. The constant volume supply device according to claim 1 or 2. In the control of the input amount based on the set time in the second input stage, the control means drives the stepping motor at a constant speed so that the opening degree of the cut gate changes from the first set opening degree to a second set opening degree within the set time.
4. The constant volume supply device according to claim 1. the control means includes a setting display unit on which the set time, the first set weight, the second set weight, the first set opening degree, and the second set opening degree are set and the set contents are displayed,
5. A constant volume supply device according to claim 1. The setting display unit sets parameters of the stepping motor for reducing the opening degree of the cut gate from the first set opening degree to the second set opening degree in the input amount control based on the set time of the second input stage, and displays the setting contents.
The constant rate supply device according to claim 5.

Images