JPS62246332A - Coffee mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a coffee mill for grinding coffee beans.

2. Description of the Related Art A conventional coffee mill having a structure as shown in FIG. 6 is known. In the figure, 1o1 is a commercial power supply, 102 is a time switch contact, and 1o3 is a start switch. This start switch f-103 is linked to the time switch 104 together with the time switch contact 102. A motor 105 drives a cutter for grinding coffee beans. If the user operates the time switch 104 to set the grinding time, the time switch contact 102 closes. Next, when the start switch 103 is pressed, the time switch contact 1o2. Start switch 103
Through the AC voltage of the commercial power source 101 is applied to the motor 106, which drives the cutter to grind the coffee beans. Then, once the set grinding time has elapsed,
Time switch contact 102 and start switch 103 open from time switch 1o4tDmJK, and motor 1
06 stops.

Problems to be Solved by the Invention However, even if the grinding time setting can be changed depending on the amount of beans, the grinding time may vary depending on the type of coffee beans, the degree of wear of the coffee bean grinding cutter, voltage fluctuations in the commercial power supply, etc. As a result, the conventional configuration described above has problems such as some coffee beans remaining unground and the rotation of the motor 105 not stopping even after grinding has been completed.

The present invention solves these problems, and aims to provide a coffee mill that can detect the completion of grinding coffee beans and stop the motor.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a grinding means for grinding coffee beans, a motor that is installed in the main body and drives the grinding means, and controls the energization of this motor. a control element, a crushing chamber attached to the main body and housing the crushing means, a sound wave detection element for detecting sound waves, and a filter that receives an output signal of the sound wave detection element and passes only a specific frequency component. a reference voltage generating means for generating a reference voltage; a comparator for comparing the output voltage of the filter means with the reference voltage; The control means outputs an ignition signal to the control element when the voltage is higher than the voltage, and outputs an ignition signal for a certain period of time when the voltage becomes lower, and then outputs a non-ignition signal.

Effect According to the above configuration, a grinding sound is generated while the grinding means is grinding the coffee beans, and once the grinding is finished, the grinding sound is no longer generated and only the motor sound is generated, so that the sound wave detection element detects the difference in sound pressure, the filter means detects the difference in sound frequency, and after detecting this, the motor is rotated for a certain period of time to prevent coffee powder from remaining in the grinding chamber, and then the motor is stopped. As a result, there are no problems such as the coffee beans leaking out or the motor not stopping even though the grinding is finished, as was the case in the past. This will ensure that the motor stops.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In FIGS. 1 to 3, 1 is a main body, and 2 is a cutter for crushing coffee beans, which constitutes a crushing means. 3 is a storage chamber for storing ground coffee bean powder, 4 is a storage chamber 3
A lid attached to the top surface, 6 a crushing chamber housing the cutter 2, 6 a motor for driving the cutter 2, 7 a sound wave detection element for detecting sound waves, which are attached to a printed circuit board 26 along with other electronic components. . 24 is a porous portion provided in a part of the peripheral wall of the grinding chamber 6, 8 is a commercial power source, and 9 is a bidirectional thyristor for controlling energization of the motor 6, which corresponds to a control element. 10 is a constant voltage power supply, resistor 11°, 12mm diode 1
3, an electrolytic capacitor 14, and a constant voltage diode 16. 30 is a filter means, and a capacitor 3
1 and a resistor 32. 16 is a reference voltage generating means, and a resistor 17. Configured by IEi. 1
9 is a comparator for comparing the reference voltage generated by the reference voltage generating means 16 and the output voltage of the filter means 30, and 2° is a start means, which is composed of a switch 21 and a resistor 22. 23 is the output signal of the start means 2o and the comparator 1
This is a control means that receives the output signal of the control element 9 as an input and outputs the signal to the control element 9.

Next, the operation of the above configuration will be explained.

The commercial power supply 8 has a resistor 11. Is it rectified by diode 13 and is an electrolytic capacitor? 14 and resistor 12.
The voltage is regulated by a constant voltage diode 16. This constant voltage serves as a power source for the reference voltage generation means 1e, the comparator 19, the start means 2o, and the control means 23. When the user opens the lid 4 of the coffee mill, puts coffee beans into the grinding chamber 5, and closes the lid 4, the setting is completed. If the switch 21 is pressed in this state, part a changes from LOW to HIGH, and is inputted to the control means 23 as an output signal of the start means 20.

Based on this input, the control means 23 outputs a signal to the bidirectional thyristor 9, ignites the bidirectional thyristor 9, and applies the AC voltage of the commercial power supply 8 to the motor 6. As a result, the motor 6 rotates the cutter 2 to grind the coffee beans placed in the grinding chamber 6. While the coffee beans are being ground, the peripheral wall of the grinding chamber S vibrates due to the grinding, and the vibration sound is transmitted to the sound wave detection element 7. As the coffee beans are ground, the particle size becomes finer and the hole diameter of the porous portion 24 becomes finer, and the coffee bean powder passes through the outer hole portion 24 due to centrifugal force and is stored in the storage chamber 3. be done. In this case, the sound pressure of the vibration sound is large when the coffee beans are being ground, and becomes small once the grinding is finished. In addition, when coffee beans are being ground, the frequency of the vibration sound is 1 due to the impact.
! @Since it is a sound, the frequency is several (h), but after the grinding is finished, it is a motor sound, so the frequency is several hundred Hz.
I feel like throwing up. On the other hand, if the capacitance of the capacitor 31 and the resistance value of the resistor 32 of the filter means 30 connected to the output of the sound wave detection element 7 are set optimally, most of the frequency components below several KHz can be cut out, so that the crushing is completed. Most of the motor noise after that can be cut out. As a result, the output voltage of the filter means 30 becomes as shown in FIG. Therefore, if the resistance value of the resistor 17.18 is set so that the reference voltage of the reference voltage generating means 1θ is optimal (as shown in C in Fig. 3), the comparator will 1
Since the non-inverting input voltage of the comparator 19 is always lower than the inverting input voltage of the comparator 19, the output of the comparator 19 is always HIGH, but while the coffee beans are being ground, the inverting input voltage of the comparator 19 is lower than the non-inverting input voltage. The output signal of the comparator 19 becomes a repeating HIGH and LOW signal. Therefore, the point at which this repeated signal changes to HIGH is the point at which the end of the grinding is detected, but since some powder may remain in the grinding chamber 5, the output signal of the comparator 19 is sent to the control means 23. Enter it and set it to HIGH.

If the output from the control means 23 to the bidirectional thyristor 9 is stopped after a certain period of time (here, 2 seconds) has elapsed since the LOW repeating signal changed to HIGH, the bidirectional thyristor 9 becomes non-active. Electricity is established, and the rotation of the motor 6 is stopped.

FIG. 4 shows another embodiment of the present invention. In the above-mentioned embodiment, a cutter was used as a component of the crushing means 2, but in this embodiment, a cutter was used as a component of the crushing means 2. It is composed of thin paper.

In this embodiment, when the coffee beans are ground in fixed quantities by the grinding means 2, the resulting coffee powder falls and is stored in the storage chamber 3. For this reason, the vibration sound is constant until the end of crushing approaches, so the output voltage of the filter 30 is constant, and when the end of crushing approaches, the output voltage decreases, and after the end, the output voltage almost disappears (fifth figure). Note that the other configurations are the same as those in the above embodiment, so the explanation thereof will be omitted.

Note that the present invention is of course applicable not only to the coffee mill in the above embodiment but also to a coffee maker equipped with a mill.

Effects of the Invention As described above, according to the present invention, the vibration sound during coffee bean grinding and the motor sound after grinding are detected by a sound wave detection element, and the end of grinding is detected using the sound pressure difference and frequency difference. Since the motor is stopped after a certain period of time has elapsed since this detection, coffee grounds are not left in the grinding chamber and the coffee beans can be reliably ground. Depending on the amount of coffee beans produced when setting the settings, the type of coffee beans, the wear of the coffee bean grinding means, and the voltage fluctuations of the commercial power supply, some coffee beans may remain unground, or some coffee beans may remain unground even though they have been ground. This solves problems such as the motor not stopping. Furthermore, in order to detect the sound of grinding coffee beans, the sonic wave detection element can be mounted in any location, such as directly mounted on a printed circuit board, making it very practical.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a coffee mill showing an embodiment of the present invention, Fig. 2 is a circuit diagram of the coffee mill, Fig. 3 is a voltage waveform diagram of various parts of the coffee mill, and Fig. 4 is a diagram of the coffee mill according to the present invention. FIG. 6 is a sectional view of a coffee mill showing another embodiment, FIG. 6 is a voltage waveform diagram of various parts of the same coffee mill, and FIG. 6 is a circuit diagram of a conventional coffee mill. 1...Main body, 2...Crushing means, 6...
... Grinding chamber, 6 ... Motor, 7 ... Sonic wave detection element, 9 ... Mountain bidirectional thyristor (control element), 16 ... Reference voltage generation means , 19... Song comparator, 23... Song control means, 30... Filter means. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
-One Body 2-6 Roles S-S Pavilion Figure 1 7-Ototomo Hochi Sachikoq〕 Acupuncture +10 Leaves/--One Piece 2- Confectionery Child 6-I Breaking Room No. 5 Figure 6/θ4

Claims (1)

[Claims] A grinding means for grinding coffee beans, a motor mounted on a main body and driving the grinding means, a control element controlling energization of the motor, and a grinding chamber mounted on the main body and housing the grinding means. , a sound wave detection element that detects sound waves, a filter means that receives an output signal of the sound wave detection element and passes only a specific frequency component, a reference voltage generation means that generates a reference voltage, and an output voltage of the filter means. a comparator that compares the output voltage with a reference voltage; the output signal of the comparator is input, and when the output voltage of the sound wave detection element is higher than the reference voltage, outputting an ignition signal to the control element;
A coffee mill comprising: a control means for outputting a non-ignition signal after outputting an ignition signal for a certain period of time when the temperature becomes low.