JPH049092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a circulating rice milling machine that automatically adjusts milling power by moving a resistor back and forth in a grain circulation path.

(Prior Art) In general, in a circulating rice mill, as time passes and rice milling progresses, the flow resistance of grains decreases and the milling power tends to decrease. For this reason, there is a conventionally known system that detects the load current of a rice milling motor that rotates a rice milling screw and automatically moves a resistor based on the detected value to keep the milling power constant ( For example, Japanese Patent Application Laid-Open No. 57-21942).

(Problem to be solved by the invention) Conventionally, in a rice milling machine equipped with an automatic polishing force adjustment mechanism that automatically moves the resistor, for example, in the middle of operation, the rice milling motor is turned off and then restarted. When restarting after interrupting the process, the resistor moves forward and applies a large amount of resistance to the grains, and this is combined with the initial resistance when restarting, causing the rice milling motor to overload. In some cases, the rice milling screw became unable to rotate.

Not only when restarting operation after such an interruption, but generally when starting operation with a resistor protruding into the grain circulation path and applying resistance (or load) to the grain,
In the past, the rice milling motor had the disadvantage of locking up due to overload, and in particular, the circulation shutter on the inlet side of the rice milling screw was kept open, and grains were loaded into the rice milling tank and the start switch was turned on, or the rice to be milled was When rice had a high moisture content, the rice milling motor was more likely to be overloaded.

The object of the present invention is to eliminate the locking (inability to rotate) of the rice milling motor due to overload, which is likely to occur at the time of startup, and to smoothly start the rice milling machine.

(Means for solving the problem) In order to achieve the above object, the present invention provides a resistor position detector that detects when the resistor has retreated, and when starting, the resistor position detector detects when the resistor has retreated. After checking this, rotate the rice polishing motor.

That is, the present invention, as shown in the functional block diagram of FIG. resistor control means 103 that outputs a retreat signal based on the signal;
resistor moving means 104 for retracting the resistor based on the retraction signal; motor control means 105 for outputting a motor start signal when the resistor is retracted based on the position detection signal; and motor control means 105 for outputting a motor start signal based on the motor start signal. It consists of a rice polishing motor M that starts rotating.

(Function) Since the present invention has the above-mentioned configuration, when the start switch 102 is turned on to start the operation of the rice milling machine, a close signal is output and the resistor control means 103 outputs a retreat signal, thereby causing the resistor to The moving means 104 retracts the resistor to minimize the resistance on the grain.

When the resistor retreats to its home position, the resistor position detector 101 detects this, and based on the position detection signal, the motor control means 105 outputs a motor start signal to start rotating the rice milling motor M, thereby starting the rice milling operation. Start.

If the resistor is already at a predetermined retracted position when the start switch 102 is turned on, the motor control means 1
05 outputs a motor start signal to immediately start the rice milling motor M without moving the resistor.

(Example) Next, embodiments of the present invention will be described based on the drawings.

Figure 2 shows the entire circulating rice mill.

Reference numeral 51 denotes a rice polishing tank, and a rice polishing screw 52 is horizontally suspended in a rice polishing chamber communicating with the bottom of the tank, and a rice polishing motor M is connected to one end of the rice polishing screw 52. 53 indicates a rice bran removal net.
54 is a circulation shutter that opens and closes the entrance to the rice milling room;
Reference numeral 5 denotes a resistor that extends into the pressure chamber 62 on the outlet side and is rotatably mounted around the base shaft 60 as a fulcrum.

As shown in FIGS. 3 and 4, a threaded rod 57 rotated by a resistor moving motor m rotatably mounted around a support shaft 56 is attached to a threaded pin 59 provided at one end of the support bar 58 of the resistor 55. Screw through the screw pin 5 by rotating the resistor moving motor m forward or reverse.
By moving the resistor 9 back and forth along the threaded rod 57, the resistor 55 is advanced into the grain flow path to the position indicated by the imaginary line or retreated to the position indicated by the solid line.

When the rice milling screw 52 is rotated by the rice milling motor M, the grains in the rice milling tank 51 are forcibly circulated in the direction of the arrows in FIGS. 2 and 3, and the resistor 55 applies resistance to the flow of the grains. The whitening power is adjusted by changing the amount of protrusion.

Reference numeral 61 denotes a pair of support plates that support both ends of the support shaft 56, and on the sides thereof, a limit switch LS1 for detecting the backward position and a limit switch LS2 for stopping the forward movement, which detect the backward position of the resistor 55, are attached to the mounting frame 63 of the motor m. It is attached oppositely above and below.

In the figure, 64 is a white rice discharge port, 65 is a knob for a starting timer TM, which will be described later, and 66 is an electrical box, which is equipped with a control circuit shown in FIG.

Next, the circuit shown in FIG. 6 will be explained.

39 is an AC power supply, 1 is an overload prevention relay, 2 is a fuse, 3 is a transformer, 4 and 8 are diode bridges, 5 is a constant voltage circuit, 6 is a rice milling motor opening/closing contact, and 7 is a current for detecting load current. It's trance.

21 and 22 are two-stage contacts of the start timer TM. When the start timer TM is set, the break contact 21 is turned on and the make contact 22 is turned off. When a certain period of time T1 has elapsed after setting, 22 is turned on, and then it is turned on again for a certain period of time. When T2 has elapsed, 21 is turned off.

Comparators 9 to 15 each receive two inputs: a reference voltage and a signal voltage. Switches 16, 17, and 18 change the reference voltages of the comparators 11 and 12 by switching the resistors 34, 35, and 36. Comparator 10
The resistors 81, 82 and 83 on the input side of the comparator 10 are 30 kilohms, and the resistor 84 is 10 kilohms, which allow the comparator 10 to operate properly.

Reference numerals 32 and 33 indicate light emitting diodes for monitoring, respectively, indicating whether the resistor moving motor m is rotating in the forward direction or in the reverse direction. 19, 20 and 29 are transistors for switches; 27 is a relay for switching the contact 25 for reversing the resistor moving motor m;
8 is a relay that switches the contact 26 for forward rotation;
30 is a relay that switches the rice milling motor opening/closing contact 6.

Diodes 43 to 45 are comparators 10 and 13.
It is for self-holding, and diodes 43 and 4
4 and line 42 are silicon diodes.

In the figure, LS3 is a limit switch for detecting opening/closing of the shutter of the white rice discharge port 64, and LS4 is a limit switch for detecting opening/closing of the circulating shutter 54, as shown in FIG.

First, the power switch 40 is closed, and then the startup timer TM is set. When the timer TM is set, the contact 21 is turned on and the contact 22 is turned off as described above, so power is supplied to the line 41 and each comparator is activated.

At this time, if the resistor 55 is neither in the forward position (position at the limit of forward movement) nor at the backward position (position at the limit of backward movement), the mounting frame 63 of the resistor moving motor m will not contact limit switches LS1 and LS2. , both of these limit switches are closed.

When limit switch LS1 is closed like this,
The comparator 10 outputs an H signal (high level signal) to the line 38, and the line 37 becomes H. In response to this H signal, the comparator 11 outputs an L signal, the transistor 19 is turned on, the relay 27 is turned on, the contact 25 is closed, and the resistor moving motor m
energize.

As a result, the resistor moving motor m is reversed, and when the resistor 55 is moved to the position shown by the solid line in FIG. , the resistor 55 stops at the retracted position. When the limit switch LS1 is opened in this manner, an L signal is input to the comparator 10, and an L signal is output to the line 38. Therefore, the line 37 changes from H to L, and the signal (analog value) from the current transformer 7 is transmitted to the comparators 11 and 12 through the line 37. Note that at this time, since the contact 22 is off as described above, the comparator 14 outputs an H signal to the line 42, and the reference voltage of the comparator 10 is not affected.

When the resistor 55 is not in the retracted position as described above, when the start switch TM is set, the resistor moving motor m is automatically reversed to retract the resistor 55. When the line 38 becomes L as described above due to the operation of the limit switch LS1, the comparator 1
3 outputs H, the transistor 29 turns on, the relay 30 closes the rice polishing motor opening/closing contact 6, and as a result, the rice polishing motor M starts. Then, the rice polishing screw 52 is rotated by the rice polishing motor M.
During the rice milling operation, the current transformer 7 detects the load current of the motor M and transmits the signal level t (analog value) to the line 37.

The comparator 11 is for controlling the resistance moving motor m in the direction of reducing the grain flow load, and the comparator 12 is for controlling the resistance moving motor m in the opposite direction.
This is to control the motor in the direction of normal rotation and increase the load. Here, the reference voltage A for comparison in the comparator 11 is set higher than that in the comparator 12, and when the value t on the line 37 is higher than the reference voltage in the comparator 11, the resistor moving motor m
is reversed, and if the value t on line 37 is lower than the reference voltage B in comparator 12, the resistor moving motor m
is rotated forward to move the resistor 55 backward or forward, respectively.

There is a dead zone between the reference voltages A and B of the comparators 11 and 12, and when the value t of the line 37 is within that range, no drive signal is output to the resistor moving motor m. This dead zone is the control target load range to be applied to the grain. Further, by switching the resistance values using the switches 16, 17, and 18 and changing the reference voltage as appropriate, the target load range is set to a value that corresponds to the moisture content and grain quality of the grains. Note that if the reference voltages A and B are set to the same value to eliminate the width of the dead zone, it is possible to control the target load state sensitively.

When the rice milling motor M starts, a signal from the current transformer 7 is transmitted to the line 37, but since the signal level t has low resistance immediately after starting, the comparator 12 acts, turning on the transistor 20, and relay 28
is activated, the contact point 26 is switched, the resistor moving motor m rotates in the normal direction, the resistor 55 moves forward, and the polishing resistance increases. As a result, the load current of the rice milling motor M increases, and the value of the line 37 gradually rises. In the target load range, the signal from the comparator 12 turns off the transistor 20 and the relay 28, and the contact 2
6 is restored, the normal rotation of the resistor moving motor m is stopped, and the resistor 55 is fixed at the target position.

In addition, when the load current increases as rice milling progresses, the comparator 11 acts to turn on the transistor 19 and relay 27, switching the contact 25 and rotating the resistor moving motor m in the reverse direction, again aiming at the target. Once it is within the load range, stop reversing.

In this way, the rice milling operation is continued by keeping the load on the rice milling motor M constant while moving the resistor 55 forward or backward by rotating the resistor moving motor m in the forward or reverse direction, and when the initially set fixed time T1 has elapsed. Contact 22 of timer TM closes.

This causes the output of comparator 14 to go low, acting on the reference voltage of comparator 10, resulting in line 38
becomes H, and therefore line 37 also becomes H. Therefore, the comparator 11 turns on the transistor 19 and the relay 27, switches the contact 25, and rotates the resistor moving motor m in the reverse direction. Then, the resistor 55 reaches the retracted position, and the mounting frame 63 releases the limit switch.
Touching LS1 turns it off, which causes the output of comparator 10 to pull line 38 low. Therefore, the input to the comparator 15 is that the line 38 is L and the line 42 is L as described above, so the output of the comparator 15 is H, the line 37 is H, and the comparator 11
The transistor 19 and relay 27 are turned on by the action of , and the contact 25 remains switched.
In other words, the resistor moving motor m remains in a position where it can rotate in reverse. However, since the limit switch LS1 is off and the resistor moving motor m is not energized, the resistor moving motor m does not rotate in reverse, and the resistor 55 remains in the retracted position.

For this reason, the grains are circulated under a minimum load condition, so that the surface of the grains is quickly debraned and well polished (bran removal cycle).

Then, after the contact 22 closes, a certain period of time T2
When , the contact 21 is opened, which turns off the power to the control unit, opens the relay 6, and stops the rice milling motor M, completing the entire rice milling process (see the flowchart in Figure 7). ).

If you want to operate manually without using a timer, rotate the Start TimerTM knob 65 in the opposite direction.
By closing contact 21 and keeping contact 22 open, line 37
Set to H. As a result, the resistor moving motor m is reversed, and when the limit switch LS1 is turned off, an L signal is output from the comparator 10, and the comparator 13 turns on the transistor 29 and the relay 30, and the relay 6 is turned on and the rice milling motor M is turned on. to start. To stop the rice polishing motor M, manually turn the knob 65 to OFF.

By the way, when the shutter of the polished rice discharge port 64 is opened during rice milling, the load is reduced and the resistor 55 moves forward. For this reason, when the shutter is closed again, the resistance applied to the grains increases rapidly and there is a risk that the grains will become clogged. However, in this embodiment, when the shutter of the polished rice discharge port 64 is opened, the limit switch LS3 is closed and the line 37 is set to H. Since the resistor 55 is forcibly moved back, the polished rice flows without clogging when the shutter is closed again.

Furthermore, if the circulation shutter 54 is closed by mistake during rice milling operation, the grains in the rice milling chamber become empty and the load on the rice milling motor M decreases. For this reason, the above-mentioned automatic resistance mechanism works and the resistor 55 moves forward in the direction of increasing the load, and when the circulation shutter 54 is subsequently opened, the rice milling motor M may be overloaded and lock stopped. In the embodiment, a limit switch LS4 is provided to detect opening and closing of the circulation shutter 54,
When the circulation shutter 54 is closed, the limit switch
LS4 is closed, line 46 is H and line 37
also becomes H, the comparator 11 is activated and the resistor 55 is forced to retreat. Therefore, the circulation shutter 54
When opening the rice polishing motor M, the rice milling motor M is not overloaded and continues to operate without any trouble. When the circulation shutter 54 is opened, the limit switch LS4 is opened and the line 46 is opened.
Since the line 37 is L and the line 37 is L, the resistor 55 is automatically controlled as usual.

Note that when the circulation shutter 54 is closed, the limit switch LS4 is operated to prevent the resistor 55 from moving forward or backward, and by fixing the resistor 55 in the same position, it is possible to avoid overload when the shutter is restarted.

FIG. 8 is another embodiment of the resistor 55, showing a support bar 58 for the resistor and a mounting frame 6 for the resistor moving motor m.
3 are connected via a fulcrum shaft 70, the screw rod 57 is screwed into a rotatably mounted screw pin 71, the screw rod 57 is rotated by a resistor moving motor m, and the fulcrum shaft 70 is moved back and forth with the motor. The movement pivots the support bar 58 and moves the resistor forward or backward.

In this embodiment, the support plate 61 shown in FIGS.
The advantage is that the number of parts is small in that it can be omitted, but in both embodiments, mechanical parts having electrical contacts such as the resistor moving motor m and limit switches LS1 and LS2 are installed outside the rice bran chamber. Therefore, it has the advantage of being dustproof and having little trouble.

Note that to move the resistor 55, a solenoid may be used instead of a motor, and to detect the position of the resistor 55, a non-contact type such as a photoelectric conversion means or a reed switch may be used instead of a limit switch. Needless to say, this is a good thing.

(Effects of the Invention) In short, according to the present invention, a resistor position detector 101 is provided to detect when the resistor 55 such as the limit switch LS1 is retracted, and when the rice milling machine is started, the resistor 55 is retracted once. Since the rice milling motor M is rotated after confirming that the rice milling motor M is rotated, the resistance applied to the grains at the time of startup is minimal, and even a small rice milling motor can start rotating smoothly. Even when restarting the operation with the resistor largely protruding after interruption, the rice milling motor M can be started without any trouble, and even an operator who is inexperienced in handling the rice milling machine can easily operate it.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of the present invention. FIG. 2 is an overall view of the circulating rice mill of this embodiment, showing the main parts in cross section. FIG. 3 is an enlarged sectional view of the front of the main part. FIG. 4 is a side view of FIG. 3. FIG. 5 is an enlarged sectional view of the circulation shutter. Figure 6 is the control circuit diagram, Figure 7
The diagram is a flowchart. FIG. 8 is a diagram showing another embodiment of the resistor moving mechanism, showing a main part thereof in cross section. 101 is a resistor position detector, 102 is a starting switch, 103 is a resistor control means, 104 is a resistor moving means, 105 is a motor control means, M is a rice polishing motor, and m is a resistor moving motor.

Claims (1)

[Scope of Claims] 1. A circulating rice mill that automatically adjusts milling power by protruding or retracting a resistor into a grain circulation path, comprising: a resistor that detects when the resistor has retreated from the grain circulation path; body position detector 101; and resistor control means 103 that outputs a backward signal based on the closing signal of the start switch 102 that starts the rice milling machine.
and a resistor moving means 104 for retracting the resistor based on the retraction signal; and a motor control means 10 for outputting a motor start signal when the resistor is retracted based on the position detection signal.
5; and a rice milling motor M that starts rotating a rice milling screw based on the motor starting signal.