JPH04288156A - Automatic cup water feeder for dental use - Google Patents

Abstract

PURPOSE:To realize an automatic cup water feeder flat by detecting a slight change in displacement as caused by the weight of a cup on a cup receiving base and the weight of water to be supplied into the cup with a non-contact magnetic field sensor. CONSTITUTION:A metal plate 3 is stuck on a cup receiving base 1 formed by a sheet to be deflected and a magnetic field sensor 4 which detects a displacement non-contact utilizing a magnetic field is set therebelow to detect a displacement generated by an external force applied to the cup receiving base as voltage signal. A voltage signal corresponding to the weight of a cup set with a water supply setting switch 11 beforehand and an amount of supply water is compared with a voltage signal to be generated with a displacement of the cup receiving base part by means of a control circuit 6 to control water supply solenoid valve 5.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic cup water supply control system and apparatus for automatically controlling water supply to a dental treatment cup.

0002

2. Description of the Related Art A conventional device for controlling the water supply to a dental cup of this kind is known from Japanese Utility Model Publication No. 56-4006, in which cup detection and water supply amount detection are performed by rotating a cup tray to detect the deflection of a coil spring, etc. The solenoid valve for water supply was controlled by changing the amount and turning on and off a contact switch or non-contact switch at a position that matched the weight of the cup and the weight of water supply. Also, special fair 2-2
There has also been devised, as disclosed in Japanese Patent No. 68757, which uses a detector such as a strain gauge at the bottom of the cup holder to detect the amount of water supplied.

0003

SUMMARY OF THE INVENTION The conventional cup water supply device as described above has the following drawbacks. The method of detecting the amount of deflection of a spring or the like also requires a large deflection stroke of the spring, resulting in an increase in size. Furthermore, since it relied on the ON/OFF operation of mechanical contacts, it lacked reliability and caused failures. In recent years, there has been a demand for flat surfaces from the standpoint of infection prevention and cleaning, and this has been difficult to meet with this configuration.

[0004] Therefore, an automatic cup water supply system using a strain gauge has been devised. FIG. 8 is a partial cross-sectional view of a conventional automatic cup water supply device using a strain gauge, but the installation of the strain gauge 34 required special techniques, making it difficult to work with, and the structure was complicated and expensive. . Furthermore, since the strain gauge 34 is attached to the elastic beam 33 at the bottom of the cup receiving sheet, its elastic force makes it difficult to generate enough strain to detect lightweight cups such as paper cups. It was impossible. In addition, the distortion state varied depending on the position of the cup and the use of a raised bottom cup, making it impossible to obtain a stable amount of water supply. The present invention was devised to solve these problems.

[0005]

The present invention solves the above problem by detecting the displacement of the cup receiving seat caused by the weight of the cup in a non-contact manner using a magnetic field sensor.

FIGS. 1 and 2 show a cup holder used to implement the apparatus of the present invention, and in the figures, 1 is a cup holder, 2 is a mounting surface, 3 is a metal plate, and 4 is a magnetic field sensor. In FIG. 1, a cup holder 1 is made of a flexible sheet of rubber, resin, or the like, and is fixed to a mounting surface 2. Figure 2
This figure shows a case in which the cup holder is formed of a plate made of metal, resin, etc., and an elastic material 32 is inserted between it and the mounting surface. In both cases, a metal plate 3 is provided at the center of the cup holder, and a magnetic field sensor 4 is installed below the metal plate 3 to detect the cup placed on the cup holder and the water supplied into the cup. The amount of displacement caused by weight is detected as a voltage signal. Then, the signal obtained from this magnetic field sensor is compared with a voltage signal corresponding to the preset weight of the cup and the set water supply amount to determine the presence or absence of the cup and to control the water supply.

FIGS. 3, 4 and 5 are conceptual diagrams showing magnetic field sensors used in implementing the apparatus of the present invention. The second claim will be explained with reference to FIG. This sensor uses a primary and secondary coil to detect changes in mutual inductance. An AC excitation power source 26 is connected to the primary side of the air-core or iron-core coil, and the secondary coil is connected to the magnetic detection section. That is. The secondary coil consists of two coils connected in series so that the secondary voltage can be applied in opposite phase, and the two secondary coils detect changes in magnetic flux due to eddy current generated in the metal plate 3 of the cup holder. However, the comparison and detection circuit 28 obtains the voltage difference between the two secondary coils.

FIG. 4 shows the primary coil and the secondary coil in the sensor.
The relationship with the next coil is reversed. When the primary coil is composed of two coils, and these two coils are connected in series so that AC excitation voltage is applied to them in opposite phases, each coil generates a magnetic field, but they work to cancel each other out. When the metal plate 3 of the cup holder approaches, the magnetic field balance is disrupted, thereby generating a voltage in the secondary coil according to the displacement.

FIG. 5 explains the third aspect of the present invention, and shows a change in the impedance of the oscillation coil detected by the magnetic field sensor 4. In FIG. The oscillation circuit 27 generates a high-frequency magnetic field in the detection coil at the tip of the sensor, and when metal approaches this magnetic field, heat loss occurs due to the induced current in the metal, changing the impedance of the oscillation coil and attenuating the oscillation. This oscillation state is detected by an oscillation state detection circuit 29 and outputted as a voltage change by an output circuit 30.

[0010] In either case, very small displacements can be detected without contact, and stable signals with high accuracy and good linearity can be obtained. Furthermore, since the structure is simple, the above-mentioned problem can be solved.

[0011]In addition, in a cup water supply device that supplies water by opening a water supply solenoid valve for a certain period of time without detecting the displacement of the cup holder portion as claimed in claim 4, a fixed non-metallic cup is used. By installing the magnetic field sensor below the cradle, it is possible to detect the presence or absence of a metal cup holder into which a metal cup or paper cup is inserted, start water supply, and control the water supply to stop after a certain period of time. be.

0012

Embodiments An embodiment of the present invention will be described below with reference to FIGS. 6 and 7. In this embodiment, as shown in FIG. 7, in order to detect the amount of water supplied, a magnetic field sensor is used, which is composed of a primary coil 13 and secondary coils 14 and 15, and detects changes in mutual inductance. FIG. 6 is a partially sectional explanatory diagram of the device of the present invention. The cup holder 1 is formed of a circular sheet of urethane rubber, and is fixed to the mounting surface 2 with a cylindrical base 9 and an O-ring 10. A metal plate 3 is attached to the lower part of the cup holder sheet. metal plate 3
An iron plate or the like with high magnetic permeability is used, and a magnetic field sensor 4 is fixed below the metal plate 3.

When an external force is applied to the cup holder 1 by the cup 7 or water supply, the magnetic field sensor 4 detects the amount of displacement between the cup holder 1 and the metal plate 3, and the control circuit 6 obtains a voltage signal corresponding to the weight. The voltage signal value obtained from the magnetic field sensor 4 is compared with a reference voltage signal value corresponding to the weight of the cup set in advance, and the presence or absence of a cup on the cup holder 1 is detected, and the water supply solenoid valve 5 is opened. water supply from the water supply port 8. Further, the control circuit 6 compares both the voltage signal value of the water supply amount set in advance with the water amount setting switch 11 and the voltage signal value obtained from the magnetic field sensor, and when the latter becomes equal to the former, the water supply solenoid valve 5 is closed. It is something.

FIG. 7 is a block diagram of the circuit of the device of the present invention. Reference numerals 13, 14, and 15 in the figure indicate coils with an air core or an iron core, and an AC excitation power source 12 is connected to the primary coil, and changes in mutual inductance are detected by the secondary coils 14 and 15. The secondary coils 14 and 15 are given the same turns ratio, and when an AC voltage is applied to the primary coil, the two secondary coils 14 and 15 have equal secondary voltages E1 and E.
2 occurs. If these two secondary voltages E1 and E2 are connected in series so that they can be applied in opposite phases, E1 = E2
If so, the output voltage E0 will be as shown in Equation 1.

[0015]

[Math 1]

That is, the output voltage E0 is E1 - E2
A voltage difference appears. When the metal plate 3 approaches this coil due to an external force applied to the cup holder, the primary coil 1
The magnetic flux generated by 3 generates an eddy current in the metal plate 3, the magnetic flux changes, and the mutual inductance changes. For this reason,
The secondary voltages generated in the secondary coils 14 and 15 are different from each other, and the difference between the voltages can be detected. This voltage difference is amplified by an AC amplifier 16 and detected 17 so that it can be easily taken into the CPU 20. Further, only the voltage difference is amplified by a DC amplifier 18, and its output is sent to an analog-to-digital converter 19.
The data is analog-to-digital converted and processed by the CPU.

By writing the water supply amount data and the cup weight into the memory 22 via the input/output device I/O 21, the water supply amount can be easily set. The water supply switch 23 is pressed in advance to set the amount of water to be stored in the cup, and the memorization is completed by pressing the water supply switch 23 again while pressing the memory switch 24. Thereafter, by placing the cup on the cup holder 1, the stored water supply data is read out, compared with the voltage signal value from the magnetic field sensor as described above, and sent to the solenoid valve drive circuit 25 via the input/output device I/O21. The system drives the water supply system to supply water.

[0018]

Effects of the Invention As is clear from the above description, according to the present invention, the detection of a cup and the amount of water supplied are made possible by detecting changes in displacement using a non-contact magnetic field sensor. It is possible to perform highly reliable detection without any problems. Furthermore, a device with a simple structure and a small size can be provided at low cost. Furthermore, since the magnetic field sensor can detect very small changes in displacement, it not only makes it easier to flatten the cup holder, but also makes it possible to detect paper cups, which greatly contributes to infection prevention.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a cup holder and a detection section according to the present invention.

FIG. 2 is a conceptual diagram showing a cup holder and a detection unit according to the present invention.

FIG. 3 is a conceptual diagram showing a detection circuit which is a component according to the present invention.

FIG. 4 is a conceptual diagram showing a detection circuit that is a component according to the present invention.

FIG. 5 is a conceptual diagram showing a detection circuit which is a component according to the present invention.

FIG. 6 is a partially sectional explanatory diagram of one embodiment of the device of the present invention.

FIG. 7 is a block diagram of a control circuit in one embodiment of the device of the present invention.

FIG. 8 is a partially sectional explanatory diagram of a conventional automatic cup water supply device using a strain gauge.

[Explanation of symbols]

1 Cup holder 2 Mounting surface 3 Metal plate 4 Magnetic field sensor 5 Water supply solenoid valve 6 Control circuit 7 Cup 8 Water supply port 9. Base 10 O-ring 11 Water volume setting switch 12 AC excitation power supply 13 Primary coil 14 Secondary coil 15 Secondary coil 16 AC amplifier 17 Detection 18 DC amplifier 19 A/D converter 20 CPU 21 I/O 22 Memory 23 Water supply switch 24 Memory switch 25 Solenoid valve drive circuit

Claims (4)

[Claims] Claim 1: In an automatic dental cup water supply device that detects a cup placed on a cup holder and supplies water into the cup, the cup holder is made of metal or metal is attached thereto, and a non-contact portion is provided below the cup holder. A dental clinic characterized in that a magnetic field sensor is installed to detect a change in the displacement of a cup holder caused by the weight of the cup and the amount of water supplied, and the magnetic field sensor detects the presence or absence of a cup and controls the amount of water supplied. Automatic cup water supply device. 2. The automatic dental cup water supply device according to claim 1, wherein the magnetic field sensor includes a primary coil and a secondary coil and a detection section for detecting a change in mutual inductance. 3. The automatic dental cup water supply according to claim 1, wherein the magnetic field sensor uses an oscillation coil that generates a high-frequency magnetic field, and further includes a detection section that detects a change in impedance of the oscillation coil due to an eddy current generated in the metal part. Device. 4. In an automatic dental cup water supply device that supplies water for a fixed period of time to a cup placed on a cup holder under timer control, metal is detected below a fixed non-metallic cup holder without contact. 4. An automatic dental cup water supply device which includes a magnetic field sensor according to claim 2 or claim 3, and detects by the sensor that a metal cup is placed on a cup holder and automatically starts water supply. 0001