JPH0524772B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a coffee mill comprising a mill mechanism driven by a motor. [Technical background of the invention and its problems] Traditionally, in this type of coffee mill,
The mill mechanism is configured to control the energization time of the motor for driving the mill mechanism, that is, the mill time, using a mechanical or electronic timer. However, the optimal milling time differs depending on the amount of milling, that is, the amount of coffee beans stored in the mill mechanism and the degree of coarseness of coffee powder desired by the user. However, there was a problem in that it was difficult to obtain coffee powder with an optimum degree of roughness that met the user's preferences. Moreover, in the conventional configuration,
Since the user has to consider the setting time every time the mill time is set by the timer,
There was a problem in that the setting operation was not only troublesome but also required a certain degree of skill. [Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to adjust the milling time by the mill mechanism, the amount of coffee beans stored in the mill mechanism, and the coarseness of coffee powder desired by the user. It is now possible to automatically control the optimum time according to the degree of grinding, and it is possible to always obtain coffee powder that is milled in the optimum state that suits the user's preference.
To provide a coffee mill that can be used extremely easily by anyone without requiring any skill. [Summary of the Invention] In order to achieve the above object, the present invention provides a current detector for detecting a load current of a motor for driving a mill mechanism when coffee beans are stored in the mill mechanism, and a current detection method using the current detector. a first storage means for storing the maximum value; a setting means for setting the degree of roughness of the coffee powder by external operation; a second storage means for storing the settings of the setting means;
Further, calculation means for determining the mill time based on the stored contents of the first storage means and the second storage means are respectively provided, and a calculation means for controlling the energization/disconnection of the motor according to the operation of the switch for starting the mill operation is provided. The control means is configured to turn on the switch means to start energizing the motor, and then turn off the switch means to cut off the power to the motor when the mill time determined by the calculation means has elapsed. This allows the energization time of the motor, that is, the milling time, to be adjusted according to the amount of coffee beans stored in the mill mechanism, the magnitude of the load current of the motor, and the coarseness of the coffee powder set by the user. It is designed to automatically change depending on the degree of severity. [Embodiments of the Invention] Hereinafter, various embodiments in which the present invention is applied to a coffee maker will be described. First, a first embodiment will be described with reference to FIGS. 1 to 4. In FIG. 2 showing the overall configuration of the coffee maker, 1 is a coffee bean grinding mechanism which is a mill mechanism consisting of a cutter 3 disposed in a mill chamber 2, and 4 is a motor for driving this coffee bean grinding mechanism 1. When energized, the cutter 3 is rotated at high speed and the coffee beans stored in the mill chamber 2 are ground to produce coffee powder. 5 is a water storage tank, 6 is a heating plate on which a bottle 7 is placed, and a heater 8 and a heating pipe 9 are attached to the lower surface of this heating plate 6. The heating pipe 9 has one end communicating with the water supply tank 5 and the other end communicating with the upper part of the mill chamber 2, and when the heater 8 is energized and generates heat,
Water from the water supply tank 5 is heated in the heating pipe 9 to generate hot water, and the hot water is raised by boiling pressure and supplied into the mill chamber 2. After passing through the coffee powder in the mill chamber 2, the hot water supplied to the mill chamber 2 is dripped into the bottle 7 through a filter 10 at the bottom of the mill chamber 2, whereby coffee liquid is extracted. In addition, 11 is a start switch arranged on the operation panel 12 and is a switch for starting the mill operation, 13
is a stop switch also located on the operation panel 12, and 14, 15, and 16 are setting means located on the operation panel 12, and selection switches for selecting the degree of coarseness of the coffee powder, ``fine,''``medium,'' and ``coarse,'' respectively. It is. FIG. 1 shows the circuit configuration of a control device installed in the coffee maker, and will be described below. However, it goes without saying that the functions of each part shown in blocks in the circuit configuration of FIG. 1 may be obtained by a microcomputer program, if necessary. Now, the motor 4 and a motor drive switch 18 serving as a switching means are connected in series to both ends of the commercial AC power supply 17, and a current detector serving as a current detector for detecting the load current is connected to the current carrying path of the motor 4. vessel 19
is mediated. Further, a series circuit including a thermostat 20, the motor 8, a temperature fuse 21, and a heater drive switch 22 is connected to both ends of the power source 17. Reference numeral 23 denotes a DC power supply circuit that is supplied with power from the power supply 17 via a step-down transformer 24, and power is supplied to each circuit section described below from its output lines La and Lb. That is, 25 is a differentiating circuit consisting of a capacitor 26 and a resistor 27, which outputs an initializing pulse P ₀ every time the power is turned on. 28 is a waveform shaping circuit that shapes the secondary side output waveform of the transformer 24 into a rectangular wave and outputs a synchronization pulse P ₁ synchronized with the power supply frequency; 29
is a frequency dividing circuit which divides the output of the waveform shaping circuit 28 to generate, for example, a 1 Hz clock pulse _P2 . The secondary output of the current transformer 19 is connected to a diode 30, a capacitor 31, and a sampling resistor 3.
2 and an A-D converter 33.
4, and this current detection circuit 34 outputs a detection signal Sa of a digital value indicating the load current of the motor 4. 35 is a motor drive circuit which turns on the motor drive switch 18 when a "1" signal is input, and turns on the "0" signal.
When the signal is input, the motor drive switch 18 is turned off. 36 is a heater drive circuit which turns on the heater drive switch 22 when a "1" signal is input, and turns off the motor drive switch 22 when a "0" signal is input. 37-40 are R-S flip-flops, 4
1 to 47 are OR circuits, 48 to 64 are AND circuits, 6
5 is a NAND circuit, and 66 to 69 are inverters. Reference numerals 70 to 82 designate transfer gates which are conductive only when a "1" signal is received at their gate terminals. Trigger circuits 83 to 86 each output a trigger pulse _P3 when the input signal rises from "0" to "1". 87,
Reference numeral 88 denotes a delay circuit, which outputs the input signal with a slight delay. 89 is a counter which counts the clock pulse _P2 inputted to the clock terminal CK via the transfer gate 70 and resets the count value to zero when the input to the reset terminal R rises. It outputs a numerical signal Sn indicating the count contents. 90 to 95 are comparison circuits that compare each input to input terminals A and B;
When A≧B, a “1” signal is output, and when A<B, a “0” signal is output. Reference numerals 96 to 99 are memory circuits, which store the data at the read terminal M at that time when the input to the trigger terminal T rises.
Store the input signal for. In this case, in particular, the memory circuits 96 and 97 have a reset terminal R, and are configured to initialize the memory contents when the input to the reset terminal R rises, and the other memory circuits 98 and 99 are configured to initialize the memory contents as follows. The memory contents are held until a trigger input is received. Reference numeral 100 denotes a comparison circuit having a different function from the comparison circuits 90 to 95, which compares the input values to the input terminals I ₁ and I ₂ when the input to the trigger terminal T rises, and selects the larger input value. It stores the stored contents and outputs the stored contents as a numerical signal Sm, and initializes the stored contents when the input to the reset terminal R rises. 101 to 103 are multiplication circuits, which multiply the respective input values to the input terminals X and Y, and output the multiplication results from the output terminal Z. 1
Reference numerals 04 to 121 are constant storage sections, in which, for example, the following constants are stored in advance. That is, the constant storage unit 104 has 2 (seconds), the constant storage unit 1
05 is 3 (seconds), constant storage section 106 is 1.4 (ampere), constant storage section 107 is 1.3 (multiply value), constant storage section 108 is 1.2 (multiply value), constant storage section 10
9 is 1.1 (multiplier value), constant storage section 110 is 20
(seconds), 13 (seconds) in the constant storage section 111, 8 (seconds) in the constant storage section 112, 18 (seconds) in the constant storage section 113
(seconds), 12 (seconds) in the constant storage section 114, 7 (seconds) in the constant storage section 115, 16 (seconds) in the constant storage section 116
(seconds), 11 (seconds) in the constant storage section 117, 6 (seconds) in the constant storage section 118, and 14 (seconds) in the constant storage section 119.
(seconds), 10 (seconds) is stored in the constant storage section 120, and 5 (seconds) is stored in the constant storage section 121, respectively. In this embodiment, the memory circuits 96 to 98 and the comparison circuit 100 constitute the first memory means 122, and the R-S flip-flops 38 to 40, the OR circuits 44 to 47, and the AND circuit 50 constitute the second memory means. Storage means 123 is configured, AND circuits 51 to 64,
Inverters 67 to 69, transfer gate 71
~82, comparison circuits 93-95, multiplication circuit 101~
103, constant storage units 106 to 121 constitute calculation means 124, and motor drive circuit 35, R-
S flip-flop 37, AND circuit 48,
The NAND circuit 65, comparison circuits 91 and 92, and constant storage section 105 constitute a control means 125. Incidentally, when the start switch 11, the stop switch 13, and the selection switches 14 to 16 are turned on, a start pulse _P4 , a stop pulse _P5 , and selection pulses _P6 , _P7 , and _P8 are output from each of them. Next, the operation of the above structure will be explained with reference to the time chart shown in FIG. In addition, this FIG. , AND circuit 51, start switch 11, R-S flip-flop 37, comparison circuit 90, trigger circuits 85, 86, comparison circuits 92, 9
1. The outputs of the NAND circuit 65, AND circuits 48 and 49, the stop switch 13, and the energization period of the heater 8 are shown in correspondence with the respective symbols. Now, when extracting coffee liquid, first, coffee beans for the number of people are stored in the mill chamber 2, and a required amount of water is supplied into the water storage tank 5. At this time, the user turns on the selection switch corresponding to the coarseness of the coffee powder desired by the user among the selection switches 14 to 16. At this time, in the second storage means 123, when the selection switch 14 corresponding to "fine" is turned on, the selection pulse _P6 output in response to this selects the R-S flip-flop 38.
is set, and the "1" signal from its output terminal Q causes the other R-S flip-flops 39, 40 to
is reset, and as a result, the fact that the coarseness of the coffee powder is set to "fine" is stored in the R-S flip-flop 38, and a "1" signal is output only to line _L1 . Furthermore, when the selection switches 15 and 16 corresponding to "medium" and "coarse" are turned on, the R-S flip-flop 39 or 40 is set by the selection pulses P ₇ and P ₈ , respectively. The fact that the coarseness of the coffee powder is set to "medium" or "coarse" is stored and a "1" signal is output to line _L2 or _L3 . When the power is turned on, all of the R-S flip-flops 38 to 40 are reset and a "1" signal is output from each reset output terminal, so the "1" signal from the AND circuit 50 is output to line _L2. Therefore, if the selection switches 14 to 16 are not operated at all, the coarseness of the coffee powder will be set to "medium".
The state set to is automatically selected. and,
After this, at time t ₁ in Fig. 3, start switch 1 is turned on.
1, a start pulse _P4 is output, and accordingly, the memory contents of the memory circuits 96, 97 and the comparison circuit 100 are initialized, and the R
-S flip-flop 37 is set and a "1" signal is output from its output terminal Q. Therefore, the transfer gate 70 becomes conductive, and the trigger pulse P ₃ is output from the trigger circuit 84 to reset the counter 89. Start counting ₂ .
Note that the memory circuits 96 and 97, the comparison circuit 100, and the counter 89 are also initialized or reset when the power is turned on and the initialization pulse _P0 is output from the differentiating circuit 25. R
-S flip-flop 37 is also reset at the same time. When the counter 89 is reset, its output, ie, the numerical signal Sn, is zero, so in the case of the comparator circuit 92, its input terminals A and B
Each input of A<B (A=0, B=3 (constant storage unit 1)
05) and outputs a "0" signal. Therefore, the NAND circuit 65 outputs a “1” signal, and the AND circuit 48 receives this “1” signal and the “1” signal from the R-S flip-flop 37 and outputs a “1” signal to the motor drive circuit 35. Start giving. Therefore, the motor drive switch 18 is turned on by the motor drive circuit 35, and in response, the motor 4 is energized to start driving the mill mechanism 1. In this case, motor 4
As shown in Fig. 4, the load current increases once and then stabilizes at a substantially constant value, and the maximum value of the load current varies depending on the amount of coffee beans stored in the mill chamber 2. Change. According to experiments conducted by the applicant of the present application, the maximum value of the load current appears 0.1 to 0.2 seconds after the start of energization.
It takes about 1 to 2 seconds to settle down to a substantially constant value. Thus, the current detection circuit 34 outputs a detection signal Sa indicating the load current of the motor 4, and the first storage means 122 receives the detection signal Sa at the read terminal M of the storage circuit 96. This memory circuit 9
The trigger terminal T of 6 is given the trigger pulse P ₃ outputted from the trigger circuit 83 in synchronization with the output of the waveform shaping circuit 28, that is, the synchronizing pulse P ₁ .
The storage circuit 96 sequentially newly stores the detection signal Sa in synchronization with the power supply frequency. At this time, the trigger pulse P ₃ is applied to the trigger terminal T of the comparison circuit 100 after being delayed by the delay circuit 87. , and a numerical signal Sm corresponding to the larger value is applied to the read terminal M of the memory circuit 97. The storage circuit 97 sequentially stores the numerical signal Sm input in this manner in synchronization with the trigger pulse ₃ from the trigger circuit 83, and the storage contents of the comparison circuit 100 are such that the level value of the detection signal Sa increases. It increases sequentially only while Therefore, as a result, the memory contents of the comparator circuit 100 (numeric signal Sm)
represents the maximum value of the detection signal Sa and thus the load current of the motor 4. After that, when the count value of the counter 89 reaches a value corresponding to 2 (seconds) corresponding to the value stored in the constant storage section 104 (time t ₂ ), each input to the input terminals A and B of the comparison circuit 90 is Since A≧B, the output of the comparison circuit 90 is inverted to a “1” signal. Then, at time _t2 , the trigger pulse _P3 is output from the trigger circuit 85 and applied to the trigger terminal T of the storage circuit 98, so that the storage circuit 98 stores the numerical signal Sm from the comparison circuit 100. The stored contents are output as a numerical signal S'm. In this case, as mentioned above, the load current of the motor 4 settles to a constant value in about 1 to 2 seconds after the start of energization, so the numerical signal S'm from the memory circuit 98 is the maximum of the load current. It indicates the value. On the other hand, the multiplication circuits 101 and 1 in the calculation means 124
02, 103, 1.4 (ampere) corresponding to the value stored in the constant storage unit 106 and the constant storage unit 10
Multiply the stored values 1.3, 1.2, and 1.1 of 7, 108, and 109, respectively, and the multiplication results are 1.82 (ampere) and 1.68
(ampere), 1.54 (ampere) comparison circuit 93,
It is applied to each input terminal B of 94 and 95. A numerical signal S'm indicating the output of the memory circuit 98, that is, the maximum value of the load current of the motor 4, is applied to each input terminal A of the comparison circuits 93, 94, and 95. Therefore, the maximum value of the load current of motor 4 is ()1.82
In each state of ampere or more, () 1.68 ampere or more and less than 1.82 ampere, () 1.54 ampere or more and less than 1.68 ampere, and () less than 1.54 ampere, the calculation means 124 functions as described below. () When S′m≧1.82 ampere……Comparison circuit 9
3, 94, and 95 respectively, and therefore, the outputs of the AND circuits 51, 52, and the inverter 69 all become "0" signals, and at this time, the AND circuits 53 to 55 output the comparator circuit 62.
It is in a state where it receives a "1" signal from and allows the signal to pass through. Therefore, when the selection switch 14 is turned on and a "1" signal is output to the line _L1 , only the transfer gate 71 becomes conductive and the stored contents of the constant storage section 110 (20 (seconds))
is applied to the read terminal M of the storage circuit 99, and when the selection switches 15 and 16 are turned on, only the transfer gates 72 and 73 are conductive, and the respective storage contents (13( seconds) or 8 (seconds)) is the memory circuit 9
It is applied to the read terminal M of No. 9. () If 1.82 ampere＜S′m≧1.68 ampere...
...“0” signal from comparison circuit 93, comparison circuit 9
A “1” signal is output from 4,95, so
A “1” signal is output only from the AND circuit 51,
The AND circuits 56 to 58 receive the "1" signal and exhibit a state in which the signal is allowed to pass. Therefore, the selection switch 14 is turned on and the line _L1
When the “1” signal is output to the transfer gate 74, only the transfer gate 74 becomes conductive and the
3 (18 seconds) is applied to the read terminal M of the memory circuit 99, and the selection switch 15,
16 is turned on, only the transfer gate 75 or 76 is conductive, and the stored contents (12 (seconds) or 7 (seconds)) of the constant storage sections 114 and 115 are transferred to the read terminal M of the storage circuit 99. given to. () If 1.68 ampere＞S′m≧1.52 ampere...
...The comparator circuits 93 and 94 output a "0" signal, and the comparator circuit 95 outputs a "1" signal.
A “1” signal is output only from the AND circuit 52,
The AND circuits 59 to 61 receive the "1" signal and exhibit a state in which the signal is allowed to pass. Therefore, the selection switch 14 is turned on and the line _L1
In a state where a “1” signal is output to
6 (16 seconds) is applied to the read terminal M of the memory circuit 99, and the selection switch 15,
16 is turned on, only the transfer gate 78 or 79 is conductive, and the stored contents (11 (seconds) or 6 (seconds)) of the constant storage sections 117 and 118 are transferred to the read terminal M of the storage circuit 99. given to. () If 1.52 ampere > S′m... Comparison circuit 9
Since the "0" signal is output from all of the inverter 69, the "1" signal is output only from the inverter 69, and the AND circuits 62 to 64 receive the "1" signal and allow the signal to pass. . Therefore, the selection switch 14 is turned on and the line
When the " ₁ " signal is output to L1, only the transfer gate 80 becomes conductive, and the stored contents (14 (seconds)) of the constant storage section 119 are applied to the read terminal M of the storage circuit 99, and the selection switch 1
In each state in which gates 5 and 16 are turned on, only transfer gates 81 and 82 are conductive, and each storage content of constant storage sections 120 and 121 (10 (seconds)
5 (seconds)) is applied to the read terminal M of the memory circuit 99. Then, as described above, "1" is output from the comparison circuit 90.
At time _t3 , which is slightly delayed from time _t2 when the signal is output, the trigger circuit 86 receives the "1" signal from the comparator circuit 90 via the delay circuit 88 and outputs the trigger pulse _P3 . The circuit 99 receives this trigger pulse _P3 and outputs its read terminal M.
The input as described above (constant storage units 110 to 1
21), and outputs the stored content as a time signal St indicating the mill time and supplies it to the comparator circuit 91. Therefore, the comparison circuit 91 receives the numerical signal Sn from the counter 89, that is, the duration of the mill operation after the motor 4 starts being energized, and the time signal St, that is, the amount of coffee beans in the mill chamber 2, as well as the selection switches 14- 16 is compared with the mill time T determined by the ON state of the mill 16, and at time _t5 when the duration of the mill operation reaches the mill time T, a "1" signal is output. At this time, the comparator circuit 92 has already outputted the "1" signal at time _t4 with the input relationship A≧B, and as a result, the "1" signal is given to both input terminals of the NAND circuit 65. Since this output is inverted to a "0" signal, the AND circuit 48 outputs a "0" signal, and the motor drive circuit 35 turns off the motor drive switch 18. Therefore, the motor 4 is cut off and the mill operation is ended. At the same time, a "1" signal is applied to both input terminals of the AND circuit 49, so the heater drive circuit 36 that receives the "1" signal from the AND circuit 49 switches the heater drive switch 22.
is turned on, and in response, the heater 8 is energized and the drip operation is started. After the dripping operation is completed, the temperature of the heating plate 6 rises and the thermostat 20 is turned off, and from then on the heater 8 is turned off.
A heat-retaining operation is performed in which the temperature is controlled by the thermostat 20. After this, the stop switch 13 is activated at time _t6 .
When is turned on, the stop pulse will start
_P5 is output and R-S flip-flop 37,
Counter 89, memory circuits 96, 97, comparison circuit 1
00 is reset or initialized, especially R-
In response to the reset of S flip-flop 37
The output of the AND circuit 49 is inverted to a "0" signal, and the heater drive circuit 36 turns off the heater drive switch 22, thereby stopping the heat retention operation. By the way, the coffee beans stored in the mill chamber 2 are set to "thin", which corresponds to the selection switches 14 to 16.
The relationship between the time Ta, Tb, Tc required to grind to each state of "medium" and "coarse" and the amount of coffee beans X, and the maximum value of the amount of coffee beans X and the load current of the motor 4. In the case of the coffee bean grinding mechanism 1 of this embodiment, the relationship is as shown in the following table.

[Table] Therefore, in this embodiment, the mill time according to the above table is obtained for the amount of coffee beans stored in the mill chamber 2 (and therefore the maximum value of the load current of the motor 4). Since the stored values in each of the constant storage units 106 to 121 in the calculation means 124 have been set, the milling time T determined by the calculation means 124 depends on the coarseness of the coffee powder selected by the user using the selection switches 14 to 16 and The coffee powder is optimized according to the amount of coffee beans stored in the mill chamber 2, so that the coffee powder can always be milled in a state that matches the user's preference, and the mill time T
is determined automatically by simply operating the start switch 11, so even a first-time user can use it extremely easily without requiring any skill. In addition, the selection switch 14~
The coarseness degree of coffee powder set by 16 is:
Once set, it remains stored in the second storage means 123, so there is no need to perform the setting operation frequently. The constants stored in the constant storage units 104 to 121 are determined according to the performance of the mill mechanism 1 or the characteristics of the motor 4. Therefore, the constants stored in the constant storage units 104 to 121 are
Of course, the storage constants 04 to 121 are not limited to those in the above embodiment, and a constant storage section for storing even more constants may be added by subdividing the ranks of the amount of coffee beans stored. . In addition, counter 8 is used for fine-grained control.
9 may be accelerated, and a time switch may be provided as a switch for starting mill operation, and the start pulse _P4 may be generated in accordance with the operation of this time switch. Next, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. That is, this embodiment is intended to provide an effective means when the individual characteristics of the motor 4 vary, and only the parts different from the first embodiment will be explained below. Reference numeral 126 designates a check switch as an auxiliary switch, which is placed on the operation panel 12 (see Figure 2) alongside the start switch 11, stop switch 13, and selection switches 14 to 16, and outputs a check pulse _P9 when turned on. do. 127, 128 are R-S flip-flops, 129-132 are OR circuits, 133-135
1 is a transfer gate, 136 and 137 are trigger circuits, and 138 is a delay circuit. Further, 139 is a counter having the same configuration as the counter 89 in the first embodiment, 140 is a comparison circuit having the same configuration as the comparison circuits 90 to 95, and 141 and 142 are memory circuits having the same configuration as the memory circuits 96 and 97. , 143 is a memory circuit having the same configuration as the memory circuits 98 and 99;
4 is a comparison circuit having the same configuration as the comparison circuit 100. 145 is a constant storage section, which contains a constant 2 (seconds)
is memorized. In this embodiment, the memory circuits 96 to 98, 141 to 143, and the comparison circuit 10
0,144 constitutes a first storage means 146, an R-S flip-flop 128, an OR circuit 1
32, AND circuits 51-64, inverter 67-
69, Transfer Gate 71-82, 133-
135, trigger circuit 136, 137, delay circuit 1
38, counter 139, comparison circuits 93 to 95, 1
40, multiplication circuits 101 to 103, constant storage unit 10
6 to 121, 145 constitute a calculation means 147, which includes a motor drive circuit 35, an R-S flip-flop 37, 127, an OR circuit 131, and an AND circuit 4.
8, a NAND circuit 65, comparison circuits 91 and 92, and a constant storage section 105 constitute a control means 148. In the above configuration, when the check switch 126 is turned on at time _t0 in the time chart of FIG. 6 before coffee beans are stored in the mill chamber 2, a check pulse P9 is output, and in response to this, a check pulse _P9 is output. The storage contents of the storage circuits 141, 142 and the comparison circuit 144 are initialized, and the R-S
Flip-flop 127 is set and a "1" signal is output from its output terminal Q. Then, the motor drive circuit 35 that receives the above-mentioned "1" signal via the OR circuit 131 turns on the motor drive switch 18 and starts to energize and drive the motor 4.
The maximum value of the load current of the motor 4 at this time is detected by the memory circuits 141, 142 and the comparison circuit 144, as in the first embodiment, and the comparison circuit 14 detects the maximum value of the load current of the motor 4 at this time.
4 will be stored as a numerical signal So.
In addition, as mentioned above, the R-S flip-flop 12
At time _t0 when the "1" signal is output from the trigger circuit 136, the counter 139 is reset by the trigger pulse _P3 from the trigger circuit 136, and at the same time, the transfer gate 133 becomes conductive. Therefore, the counter 139 is
The counting operation starts from the ON operation time t ₀ of 6,
After this, when reaching time t' ₀ at which two seconds stored in the constant storage section 145 have elapsed, the comparator circuit 140 outputs a "1" signal and the trigger circuit 137 outputs a trigger pulse P ₃ . Then, the memory circuit 1 receives the trigger pulse _P3 at the trigger terminal T.
43 stores the numerical signal So from the comparator circuit 144 as a numerical signal S'o as an auxiliary value, and at the same time, the R-S flip-flop 127 is reset by the trigger pulse _P3 , so that the motor drive circuit 35 receives "0". '' signal is applied, the motor drive switch 18 is turned off, and the drive of the mill mechanism 1 is thereby stopped. Also, at this time t' ₀ , the trigger circuit 1
Trigger pulse _P3 from 37 sets R-S flip-flop 128, and its output terminal Q
Transfer gate 1 is activated by the “1” signal from
34 exhibits a conductive state. Therefore, the memory circuit 14
The numerical signal S'o from 3 is sent to the multiplier circuits 101 to 10.
3, instead of the output from the constant storage unit 106. After that, when the coffee beans are stored in the mill chamber 2 and the start switch 11 is turned on in this state,
The calculation means 147 receives the numerical signal S'o (i.e., the motor 4
The milling time is determined by the milling time (a value corresponding to the characteristics of will be carried out. still,
When the check switch 126 is not turned on, the R-S flip-flop 128 is not set and a "1" signal is output from its output terminal, so that the transfer gate 135 is in a conductive state. 11 is turned on, the mill time is determined based on the stored value in the constant storage section 106 in the same manner as in the first embodiment. Furthermore, the R-S flip-flops 127 and 128, the counter 139, the memory circuits 141 and 142, and the comparison circuit 144 are also reset or initialized when the power is turned on and the initialization pulse _P0 is output from the differentiating circuit 25. It is something that will be done. According to the present embodiment described above, the motor 4 is operated in a state where no coffee beans are stored in the mill chamber 2.
Since the calculation of the mill time by the calculating means 147 is corrected based on the maximum value of the load current of Even if the voltage value of step 4 fluctuates, coffee beans can always be milled in a constant state. Moreover, since the numerical signal So, which is a determining factor for the mill time, remains stored in the memory circuit 143, once the no-load current of the motor 4 is checked by the check switch 126, accurate mill operation can be performed any number of times. be able to. Note that in each of the above embodiments, the first storage means 12
When detecting the maximum load current value of the motor 4 at step 2, 146, the configuration is such that the maximum load current value of the motor 4 is stored when the time corresponding to the value stored in the constant storage section 104 or 145 has elapsed, but the present invention is not limited to this. It goes without saying that a known maximum value detection means may be used, such as a configuration in which the maximum value of the load current is sequentially detected and stored when the maximum value is determined. In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications within the scope of the invention, for example, it may be applied to a single coffee mill. . [Effects of the Invention] According to the present invention, as is clear from the above description, in a coffee mill in which the milling mechanism is driven by a motor, the milling time of the milling mechanism is stored in the milling mechanism. The time can be automatically controlled to be the optimum amount according to the amount of coffee beans and the coarseness of coffee powder desired by the user, so that the mill is always in the optimal condition that matches the user's preferences. This method has the excellent effect of not only making it possible to obtain coffee powder but also being extremely easy to use even as a bullet without requiring any skill.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a block diagram, FIG. 2 is a partially cutaway side view of the entire coffee maker, and FIG.
The figure is a time chart for explaining the operation, and FIG. 4 is a time change characteristic diagram of the load current of the motor. Also the fifth
1 and 6 correspond to FIG. 1 and FIG. 3, respectively, showing a second embodiment of the present invention. In the figure, 1 is a mill mechanism, 2 is a mill chamber, 4 is a motor, 11 is a start switch (switch for starting mill operation), 13 is a stop switch, 14 to 16
18 is a selection switch (setting means); 18 is a motor drive switch (switch means); 19 is a current transformer (current detector); 122 and 146 are first storage means;
123 is a second storage means, 124 and 147 are calculation means, 125 and 148 are control means, and 126 is a check switch (auxiliary switch).

Claims (1)

[Claims] 1. A motor for driving a mill mechanism, a switch means for controlling power on/off of this motor, and a load current of the motor when coffee beans are stored in the mill mechanism. A current detector for detecting, a first storage means for storing the maximum value of the current detected by the current detector, and a setting means for setting the degree of roughness of the coffee powder by external operation;
a second storage means for storing the setting contents of the setting means; a calculation means for determining the mill time based on the stored contents of the first storage means and the second storage means; and operation of a mill operation start switch. control means for turning on the switch means to start energizing the motor in response to the operation, and turning off the switch means to cut off the power to the motor when the mill time determined by the calculation means has elapsed. A coffee mill that is characterized by: 2 The first storage means is provided to store, as an auxiliary value, the maximum value of the detected current value when no coffee beans are stored in the mill mechanism according to the operation of the auxiliary switch, and the calculation means The coffee mill according to claim 1, wherein the coffee mill is configured to correct the calculation content of the mill time based on the auxiliary memory value. 3. A patent characterized in that the control means is configured to turn on the switch means in response to the operation of the auxiliary switch, and then turn off the switch means when the storage means stores the auxiliary memory value. A coffee mill according to claim 2. 4. The coffee mill according to claim 2, wherein the first storage means is configured to hold the auxiliary value once stored until the auxiliary switch is operated next time. 5. Claim No. 5, characterized in that the second storage means is configured such that once the setting contents of the setting means are stored, the second storage means retains the stored contents until the setting means is operated next time. The coffee mill according to item 1. 6. The coffee mill according to claim 1, wherein the second storage means is configured to automatically store a predetermined roughness degree of coffee powder in response to power-on. .