JPS6132009B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coffee maker equipped with a ringer for notifying completion of extraction of coffee liquid.

The heating device is configured to heat water using a heater as a heat source and supply the water to a coffee liquid extraction case containing coffee grounds while the heating device is turned off when the temperature of the heating device exceeds a predetermined value. In the case of a coffee maker equipped with a normally closed temperature switch and a buzzer for notifying the completion of extraction of coffee liquid that sounds when the temperature switch is turned off, a heater drive circuit, for example, a buzzer, is used to drive the heater. Typically, the contacts of the relay, the temperature switch, and the heater are connected in series to the AC power source, and a buzzer drive circuit, such as a buzzer drive relay, is provided, which is activated when the temperature switch is turned off. Further, both relays are configured to be supplied with power from the same DC power supply circuit. However, in this type of coffee maker, the heater drive relay is always operated in order to keep the extracted coffee liquid warm, so when the buzzer drive relay is operated, the output of the DC power supply circuit is This results in a doubling of the load current, which requires a DC power supply circuit with a large capacity, resulting in an increase in cost.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coffee maker in which the capacity of a DC power supply circuit serving as a common power supply for a heater drive circuit and a buzzer drive circuit can be reduced, thereby reducing costs.

An embodiment in which the present invention is applied to a coffee maker having both a hot water supply (drip) mechanism and a mill mechanism will be described below with reference to the drawings.

1 is a lid switch, which is configured to be turned on only when the lid of the case (none of which is shown), which is used for both grinding coffee beans and extracting coffee liquid, is properly set in a predetermined position. The lid switch 1, the heater 2, the bimetal switch 3 as a temperature switch, and the output switch 4a of the heater drive circuit 4, which will be described later, are connected in series in this order between both output terminals 5a and 5b of the AC power source 5. A heater circuit A is constituted by these series circuits.
Then, a series circuit of a mill motor 6 and an output switch 7a of a motor drive circuit 7 to be described later is connected in parallel with the series circuit of the heater 2, bimetal switch 3, and output switch 4a. In this case, the motor is attached to a mill mechanism (not shown), and the mill mechanism has a cutter rotated by the motor 6 in the case, and the coffee beans stored in the case are rotated by the cutter. Grind to produce coffee powder. Further, the heater 2 is attached to a hot water supply mechanism (not shown), and the hot water supply mechanism includes:
The water supplied from the water storage tank to the heater, which is the object to be heated, is turned into hot water by the heater 2, and the boiling pressure of the water thus produced is used to supply it into the case containing the coffee powder, thereby producing coffee liquid. Configured to extract. Further, the bimetal switch 3 is of a normally closed type that is turned off when the heater reaches a predetermined temperature, while the bimetal switch 8 rectifies the output of the AC power supply 5 and controls the control circuit 9 to be described later. It is a DC power supply circuit for supplying power.
In the figure, only the low potential side (zero potential side) output line 8a among the output lines is shown. 10 is a detection circuit for determining the state of the heater circuit A, which will be described below. That is, the common connection point of the heater 2 and the bimetal switch 3 in the heater circuit A constitutes a signal extraction point 11, and this signal extraction point 11 is connected to the detection circuit 10 via a resistor 12.
Connected to the base of PNP type transistor 13 inside. The emitter of the transistor 13 is connected to the output terminal 5b of the AC power supply 5, the collector of the transistor is connected to the low potential side output line 8a of the DC power supply circuit 8 via the resistor 14, and the base of the transistor 13 is connected to the output terminal 5b of the AC power supply 5. Resistance 15 between emitters
and a diode 16 in parallel circuit. Then, the collector of the transistor 13 forming the output end of the detection circuit 10 is connected to the line _L1 .

Now, the configuration of the control circuit 9 will be described below. In this case, most of the functions of the control circuit 9 can be obtained by a program of a microcomputer, but here, for convenience of explanation, a combination of block circuits will be described. It is shown with. That is,
A frequency divider 17 divides the frequency of the output of the AC power supply 5, and outputs a counting pulse Pc at a period of, for example, 1 Hz. Reference numeral 18 denotes a set switch that is turned on only in the manual operation state, and a high level signal is applied to one input terminal of the AND circuit 19 only when this switch is turned on. The other input terminal of the AND circuit 19 is connected to receive the counting pulse Pc, and therefore, the AND circuit 19 passes the counting pulse Pc only during the ON period of the set switch 18. For example, 20 is a hexadecimal up counter, which is the clock input terminal from the AND circuit 19.
It adds and counts the pulses input to CK and outputs the counted contents as a digital signal Sn. 21 is, for example, 3 consisting of a 7-segment light emitting diode, etc.
digit digital display, this is the digital signal
When Sn is received through the transfer gate 22, a numerical value (two digits at most) corresponding to the digital signal Sn is displayed. The transfer gate 22 has a configuration that exhibits low impedance and allows the signal to pass only when a high level signal is input to its control terminal 22a, and the other transfer gates described below have the same configuration. be.
A storage circuit 23 stores a display information signal Sd of a predetermined mode, and the information signal Sd is input to the digital display 21 when the transfer gate 24 is in a conductive state. When the information signal Sd is input to the digital display 21, the digital display 21 displays, for example, "LId" as shown in FIG. On the other hand, 25 is a start switch that is turned on only in the manual operation state, and when this is turned on, a high level signal is given to one of the input terminals of the 3-input type AND circuit 26. 27
is also a stop switch that is only turned on during manual operation, and when it is turned on, the line
A high level signal is output to _L2 . 28 has its set input terminal S connected to the output terminal of the AND circuit 26, and its reset input terminal R connected to the line.
The output from the set output terminal Q of the R-S flip-flop connected to _L2 is the delay circuit 29.
is applied to one input terminal of the AND circuit 30 via the input terminal, and also directly applied to one input terminal of the other AND circuit 31.
The other input terminal of the AND circuit 31 is connected to the line _L1 .
It is connected to. At this time, the delay circuit 29 is
The delay time is set to about 20ms, for example. The delay circuit 29 is located downstream of the delay circuit 29.
The output terminal of the AND circuit 30 is connected to the control terminal 22a of the transfer gate 22 via an inverter 32, and is also directly connected to the control terminal 24a of the transfer gate 24. is AND
The transfer gate 24 is conductive when the circuit 30 outputs a low level signal, and the transfer gate 24 is conductive when the AND circuit 30 outputs a high level signal. 33 is an RS flip-flop whose set input terminal S is connected to the output terminal of the AND circuit 31 and whose reset input terminal R is connected to the line _L2 . is applied directly to the other input terminal of the AND circuit 30 and is applied directly to the monostable multivibrator 35 which outputs a high level signal for a short time when receiving a rising signal, and is also applied to the AND circuit 37 via a delay circuit 36. It is designed so that it can also be applied to one input terminal of the . 38 is a down counter having a preset function and a clear function;
This presets the numerical value corresponding to the input digital signal when a digital signal is input to the data input terminal D, and also presets the value corresponding to the input digital signal.
Each time a pulse is input to CK, the count is subtracted from the preset value, and when a high level signal is input to the clear terminal CL, the count value is cleared to "0". Furthermore, this down counter 38 is configured to output a high level signal only during a period when its count value is other than "0", and operate the motor drive circuit 7 with this high level signal, so that the motor drive circuit 7 is operated. When the circuit 7 is operated properly, it turns on its output switch 7a. Further, the data input terminal D of the down counter 38 is connected to the output terminal P of the up counter 20 via the transfer gate 39, the clock input terminal CK is connected to the output terminal of the AND circuit 40, and the clear input terminal CL is connected to the output terminal P of the up counter 20. Connected to the line _L2 . One input terminal of the AND circuit 40 is connected to receive the counting pulse Pc, and the other input terminal is connected to the output terminal P of the down counter 38. The control terminal 39a of the transfer gate 39 is connected to receive the output from the monostable multivibrator 35. Further down counter 38
The output terminal P of the AND circuit 26 is connected to the input terminals of the AND circuits 26 and 37 after passing through an inverter 41 and being branched into two, and the remaining input terminals of the AND circuit 26 are connected to the AND circuit 37 via an inverter 42.
is connected to the output terminal of the Also, the above AND
The output terminal of the circuit 37 is connected to one input terminal of an AND circuit 44 via a delay circuit 43 with a delay time of about 10 ms, for example.
Line _L1 is connected to the other input terminal of 4. 45 is a D flip-flop whose data input terminal D is connected to a high level signal source 46;
Its clear input terminal CL is connected to line _L2 , and its clock input terminal CK is connected to the output terminal of AND circuit 44. 47 is a monostable multivibrator that outputs a high level signal for a predetermined period in response to the rise of the output of the D flip-flop 45 to a high level signal; its output is sent to the AND circuit 49 via an inverter 48; In addition to being applied to one input terminal, it is also applied directly to a buzzer drive circuit 50 which is a ringer drive circuit, and at this time, the inverter 48 and
The AND circuit 49 constitutes a stop circuit B in the present invention. This buzzer drive circuit 50 causes a buzzer 51, which is a ringer for notifying completion of extraction of coffee liquid, to ring only during a period when a high level signal is input. On the other hand, the AND circuit 49 is connected to give its output to the heater drive circuit 4, and this heater drive circuit 4 is operated while the high level signal is being input to turn on the output switch 4a. This is a configuration that allows still,
The other input terminal of the AND circuit 49 is the AND circuit 37
is connected to the output terminal of the

Next, the operation of this embodiment having the above configuration will be explained. When producing coffee liquid, an amount of water corresponding to the desired number of people is supplied into the water storage tank of the hot water supply mechanism, and with the corresponding amount of coffee beans stored in the case, the lid is placed on the case. A bottle for storing coffee liquid is placed on the heater of the hot water supply mechanism. Then, in this state, coffee beans are first milled. In this case, when the set switch 18 is turned on and kept in the on state, the count pulse Pc from the frequency divider 17 is given to the up counter 20 via the AND circuit 19, which adds and counts the count pulse Pc. The content of the count is then output as a digital signal Sn. At this time,
As will be clear from the description below, since the AND circuit 30 outputs a low level signal and the transfer gate 22 is conductive, the digital display 2
1 will now receive the digital signal Sn,
Therefore, on the digital display 21, the numerical value corresponding to the digital signal Sn changes from "0" to "1" to
Since the display is sequentially increased from "2" to "3", etc., the operator releases the on operation of the set switch 18 when the display reaches an arbitrary value, for example "12". In this way, set switch 1
8 is released, the high level signal is no longer input to the AND circuit 19 and the AND circuit 19 blocks the passage of the counting pulse Pc, so the up counter 20 stops counting operation. Then, the count value "12" which is the count result is stored, and a digital signal Sn corresponding to the count value "12" is output. Therefore, at this time, the digital display 21 continues to display "12". After this, when the start switch 25 is turned on, in this case, as will be understood from the description below, a high level signal is output from the inverters 41 and 42, so a high level signal is output from the AND circuit 26, and this high level signal is output from the AND circuit 26. The RS flip-flop 28 which receives the signal at its set input terminal S is set and outputs a high level signal from its set output terminal Q. However, in such a state, if the lid of the case is not properly set at the predetermined position, the lid switch 1 is off, and the output switch 4a is also off, so the signal extraction point 11 is turned off. Since no base current serving as a detection current is applied to the base of the transistor 13, the transistor 13 is in an off state. Therefore, a low-level signal corresponding to the potential of the low-potential side output line 8a of the DC power supply circuit 8 is output to the line _L1 , and the AND circuit 31 continues to output the low-level signal. The RS flip-flop 33 also maintains the reset state and outputs a low level signal from its set output terminal Q. As mentioned above, when a high level signal is output from the R-S flip-flop 28, the high level signal is sent to the delay circuit 28.
9 to one input terminal of the AND circuit 30, and the low level signal from the R-S flip-flop 33 to the other input terminal of the AND circuit 30 via the inverter 34. Then, a high level signal is output from the AND circuit 30, and the transfer gate 24 becomes conductive. Then, the information signal Sd from the memory circuit 23 is input to the digital display 21, which starts to display "LId" (see Figure 2), thereby notifying the user that the lid is not properly set. It will be done. Incidentally, when the start switch 25 is turned on with the lid not properly set, the monostable multivibrator 35 is driven because a high level signal is not output from the R-S flip-flop 33 as described above. Therefore, the transfer gate 39 maintains a non-conducting state. Therefore, down counter 3
8, the digital signal Sn is not input to the data input terminal D of the down counter 3.
Since 8 continues in its initial state, that is, its count value is "0" and it outputs a low level signal,
The motor drive circuit 7 prevents its output switch 7a from being turned on, thereby maintaining the motor 6 in a non-energized state. That is, the milling operation will not be started unless the lid is properly set. On the other hand, when the case lid is properly set in the predetermined position, the lid switch 1 is on and the output switch 4a is off, so that every half wave period when the output terminal 5b side of the AC power source 5 is at a high level. A base current is supplied from the signal extraction point 11 to the transistor 13, and the transistor 13 is turned on periodically according to the frequency of the AC power supply 5. For this reason, line L ₁
A high level signal is intermittently outputted every time the transistor 13 is turned on. Therefore, if the lid is not properly set, the start switch 25
When the lid is normally set again based on the display "LId" on the digital display 21 as described above after the lid is turned on, and when the start switch 25 is turned on with the lid set normally. In this case, a high level signal is input to both input terminals of the AND circuit 31, and this AND circuit 31 outputs a high level signal, so the R-S flip-flop 33 is set and a high level signal is output from its set output terminal Q. Output. Then, the monostable multivibrator 35 driven by this low-level signal outputs a high-level signal for a short period of time to make the transfer gate 39 conductive, so that the digital signal Sn stored in the up counter 20 becomes the data input of the down counter 38. The down counter 38 presets a numerical value "12" corresponding to the input digital signal Sn, and outputs a high level signal from the output terminal P to operate the motor drive circuit 7. This turns on the output switch 7a and energizes the motor 6, which rotates the cutter and starts grinding the coffee beans in the case. Also,
At the same time, the high level signal is output to the AND circuit 40.
is applied to one input terminal of the AND circuit 4.
Counting pulse Pc given to the other input terminal of 0
passes through this, and the down counter 38, which receives the counting pulse Pc at its clock input terminal CK, starts a subtractive counting operation. Such a subtraction counting operation is started with the preset value "12" as a reference, and the counted value is sequentially decreased from "12" to "11" to "10", and so on. When the count value of the down counter 38 reaches "0", a low level signal is output from the output terminal P instead of a high level signal, so the motor drive circuit 7 is stopped and its output is The switch 7a is turned off, and the motor 6
At the same time as the power is cut off and grinding of the coffee beans is completed, the AND circuit 40 is turned off and the input of the counting pulse Pc to the down counter 38 is stopped. Therefore, the time it takes for the count value of the down counter 38 to go from "12" to "0" is 12 seconds because the output cycle of the count pulse Pc is 1 Hz, and therefore The time (mill time) is controlled to 12 seconds. As mentioned above, when a high level signal is output from the set output terminal Q of the R-S flip-flop 33, the high level signal is inverted by the inverter 34 and input to the AND circuit 30.
0 comes to output a low level signal, therefore, the transfer gate 22 becomes conductive and the digital display 21 comes to display the numerical value "12" corresponding to the digital signal Sn from the up counter 20. Furthermore, since the R-S flip-flop 28 in the reset state is outputting a low level signal before the start switch 25 is turned on, this low level signal is received via the delay circuit 29.
The AND circuit 30 outputs a low level signal as described above. Furthermore, the delay circuit 29
Since the high level signal output to _L1 is intermittent, this is provided to compensate for this.

Now, when the milling operation is completed as described above, the operation automatically shifts to the dripping operation. That is, when the down counter 38 outputs a low level signal and the milling operation is completed, the inverter 41 that has received the low level signal outputs a high level signal, and this high level signal is sent to the AND circuit 37.
is applied to one input terminal of . At this time, AND
A high level signal is input to the other input terminal of the circuit 37 via the delay circuit 36 at the time when the high level signal is output from the flip-flop 33 (in other words, at the time when the milling operation is started). Therefore, as a result, the AND circuit 37 outputs a high level signal in place of the previous low level signal at the same time as the milling operation ends.
This high level signal is passed through the delay circuit 43.
In addition to applying it to one input terminal of the AND circuit 44,
It is also applied directly to the other input terminal of the AND circuit 49. In this case, at the moment when a high level signal is output from the AND circuit 37, a low level signal is applied to one input terminal of the AND circuit 44 (the input terminal connected to the delay circuit 43), and the AND circuit 44 receives a low level signal.
Since the circuit 44 is outputting a low level signal,
The D flip-flop 45 is in an initial state (clear state) and outputs a low level signal from its output terminal Q, and the monostable multivibrator 47
outputs a low level signal when in the non-drive state,
Inverter 48 receiving this outputs a high level signal. Therefore, the AND circuit 37 receives the high level signal at the moment it is output.
Since the circuit 49 outputs a high level signal, the heater drive circuit 4 is operated and the output switch 4a is turned on, so that the heater 2 is energized and generates heat. When the output switch 4a is turned on in this way, the base current is no longer supplied to the base of the transistor 13 from the signal take-out point 11 and the transistor 13 is turned off, so that a low voltage is applied to the line _L1 . A level signal is now output, and therefore a low level signal is applied to the input terminal of the AND circuit 44 connected to line _L1 . Here, the delay circuit 4
The delay time 3 is set to, for example, 10 ms, which is longer than the delay time from the time when the high level signal is output from the AND circuit 37 to the time when the output switch 4a is turned on and the low level signal is output to the line _L1 . Therefore, when the AND circuit 37 outputs a high level signal, the AND circuit 44
The delay action of the delay circuit 43 prevents a high level signal from being input to both input terminals at the same time. Due to this action, the D flip-flop 45 is maintained in its initial state. Now, as mentioned above, when the heater 2 is energized and generates heat, the water in the heater supplied from the water storage tank is heated by the heater 2 and becomes boiling water, and the hot water thus generated is heated by its boiling pressure. The coffee liquid is extracted by being supplied into the case, and the extracted coffee liquid flows down and is stored in a bottle placed on a heater. When all the water in the water storage tank is consumed by such coffee liquid extraction or dripping operation, the temperature of the heater will rise rapidly due to no heat exchange between the heater and the water. The bimetal switch 3 detects this and turns off the heater 2, thereby completing the dripping operation. When the dripping operation is completed as described above, that is, when the bimetal switch 3 is turned off, the base signal is again applied from the signal extraction point 11 to the base of the transistor 13, and the transistor 13 is turned on. A high level signal will be output intermittently to _L1 . Then, a high level signal is input to both input terminals of the AND circuit 44, and the AND circuit 4
4 will now output a high level signal, so
The D flip-flop 45 is triggered and outputs a high level signal, and in response, the monostable multivibrator 47 outputs a high level signal for a predetermined period. Therefore, the buzzer drive circuit 5
0 is operated for a predetermined period and the buzzer 5 is activated during this period.
1 sounds to notify that the dripping operation has been completed. Then, while the buzzer 51 is ringing, that is, while the monostable multivibrator 47 is outputting a high level signal, the high level signal is inverted to a low level signal by the inverter 48 and input to the AND circuit 49. Therefore, a low level signal is output from the AND circuit 49, and the operation of the heater drive circuit 4 is temporarily stopped. After the above-described dripping operation is completed, the bimetal switch 3 is intermittently turned on and off to control the heater 2 to be turned on and off, and the coffee liquid in the bottle is kept warm by the heater. To stop such heat retention, the stop switch 27 is turned on.
Then, due to the high level signal output to line _L2 due to the on operation, the R-S flip-flops 28, 33, down counter 38 and D
All the flip-flops 45 are reset or cleared, and in particular, by resetting the R-S flip-flop 33, a low level signal is input to the AND circuit 37, and the AND circuit 49 at the subsequent stage is inputted to the AND circuit 37.
A low level signal is output from the heater drive circuit 4, and the operation of the heater drive circuit 4 is stopped, and the heater 2 is cut off, that is, the heat retention is stopped. Furthermore, if the stop switch 27 is turned on during the above-described dripping operation, the heater 2 is similarly cut off and the dripping operation is stopped midway. Furthermore, stop switch 2 is activated during mill operation.
When 7 is turned on, down counter 3
Since the count value of 8 is cleared to "0" and a low level signal is now output, the motor drive circuit 7 is stopped and the motor 6 is cut off, and the mill operation is stopped midway. Ru. Note that the delay circuit 36 prevents a situation in which high-level signals are input to both input terminals of the AND circuit 37 at the same time at the start of the mill operation, that is, at the moment when the high-level signal is output from the R-S flip-flop 35. It is set up for the purpose of

According to the present embodiment described above, the operation of the heater drive circuit 4 is temporarily interrupted by the stop circuit B consisting of the inverter 48 and the AND circuit 49 while the buzzer 51 is ringing, that is, while the buzzer drive circuit 50 is operating. In other words, the buzzer drive circuit 50 is operated when the heater drive circuit 4 is in a stopped state)
Therefore, the capacity of the DC power supply circuit 8, which serves as a common power supply for both drive circuits 4 and 50, can be reduced. That is, if both drive circuits 4 and 50 were each constructed of relays, for example, the total load current would be about 30 mA, but according to this embodiment, both drive circuits 4 and 50 can be operated simultaneously. Since there is no load current, the load current only needs to be 15 mA at all times, thereby making it possible to reduce the capacity of the DC power supply circuit 8.

In summary, according to the present invention, it is possible to provide a coffee maker in which the capacity of the DC power supply circuit serving as a common power supply for the heater drive circuit and the buzzer drive circuit can be reduced, thereby reducing costs.

[Brief explanation of the drawing]

FIG. 1 is an electrical configuration diagram showing an embodiment of the present invention, and FIG. 2 is a front view showing an example of one state of a digital display in the embodiment. In the figure, 2 is a heater, 3 is a bimetal switch (temperature switch), 4 is a heater drive circuit, 8 is a DC power supply circuit, 21 is a digital display, 48 is an inverter, 49 is an AND circuit, B is a stop circuit, and 50 is a A buzzer drive circuit (sounder drive circuit), 51 is a buzzer (sounder).

Claims (1)

[Claims] 1 A temperature switch that detects the temperature of a heater for boiling water, a sounder drive circuit that drives a sounder for notifying coffee liquid extraction completion in accordance with the operation of the temperature switch, and a heat source for the heater. and a heater drive circuit for forming an energization circuit for the heater, in which a DC power supply circuit is provided as a common power source for the sounder drive circuit and the heater drive circuit, and the sounder drive circuit is connected to the heater drive circuit. A coffee maker characterized in that it is configured to be operated when the drive circuit is in a stopped state.