JPS5946003B2 - Aerial ultrasonic position control device for tables or chairs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an airborne ultrasonic position control device for a dental or other medical treatment or treatment table or a barber or beauty chair, and more specifically, for controlling the relative straight line position of these tables or chairs. The vertical movement and tilting of a first member (for example, a base) and a second member (for example, a seat, a backrest, a headrest, etc.) whose facing distance changes with movement can be detected using aerial ultrasonic pulses as a position detection medium. The present invention relates to a device for automatically controlling electronically using the present invention.

The present invention will be explained below by taking a dental treatment table as an example and comparing it with the prior art.

1 and 2 are a front view and a partially cutaway plan view showing an example of a dental treatment table equipped with the device of the present invention. 1
A base 3 is placed on the floor 2, and a seat 5 is raised and lowered while maintaining a substantially horizontal state by a cylinder shaft 4 of a hydraulic lifting mechanism (not shown) built into the base 3.
, a backrest 9 that tilts back and forth around a rotating shaft 8 by expansion and contraction of a cylinder shaft 7 of a hydraulic tilting mechanism 6 with respect to this seat 5;
0, and a headrest 11 which can also be tilted forward and backward via the hood 2. The lifting and lowering of the seat 5 and the tilting of the backrest 9 are controlled by the lifting and lowering pedals 120 and tilting pedals 121 of the hood pedal device 12 placed on the floor 2. It is performed artificially through manipulation.

In other words, the base 5 is the first member, which is the base 3,
It becomes a second member that changes the facing distance by linear motion (elevating motion), and on the other hand, the tilting of the backrest 9 with respect to the seat 5 is replaced by the linear telescopic motion of the cylinder shaft 7 of the hydraulic tilting mechanism 6. In this case, the hydraulic tilting mechanism 6 fixed part 70
When the cylinder shaft 7 is the first member, the cylinder shaft 7 becomes a second member that changes its opposing position by linear motion, and the distance between these first and second members is artificially controlled. It turns out. By the way, from the current state of dental treatment diagnosis,
When continuously treating a large number of patients, the doctor or his/her assistant can position the table appropriately for various treatment positions while taking into account the individual differences of the patients, simply by operating the food pedal as described above. Since this would require significant additional effort for them, proposals have recently been made to control the position of the table electrically, and some methods have already been put into practice. The problems are pointed out below. (1) Corresponding to the height of the seat, a position detection device including a potentiometer is linked to the seat lifting mechanism (hereinafter referred to as the drive unit), and the position of the seat is determined as the electrical resistance value of the potentiometer. For example, Japanese Patent Publication No. 53-41477 discloses a system that reads the desired position of the seat and extracts the actual position of the seat as the difference between the resistance values and operates and controls the driving section.

This has the following problems. In other words, a structure in which the rotary shaft of the potentiometer and the drive part are mechanically interlocked to cause the resistor to slide is considered unavoidable, so the reliability of the detected resistance value is reduced even when wear occurs due to sliding contact. sex becomes lower,
The loss of reliability is further exacerbated by mechanical errors in the motion mechanism.

Therefore, in order to use a potentiometer in a non-heat generating area, it is necessary to use a highly reliable and expensive potentiometer.
This will increase costs. (Ii) A multi-tier seat with a desired height is provided, a limit switch is placed in each stage, and a mechanical actuator linked to the drive unit of the seat is provided, and one of the limit switches is selected by the actuator. In the case where the pedestal is controlled to a certain height by manually operating the pedestal, the desired predetermined position cannot be changed from the outside.

(111) A system has been proposed in which the movement of the seat to a desired position is controlled by timed driving of a motor or hydraulic pressure by setting a timer value. In the case of a hydraulically driven timed stop, the stop position tends to vary depending on the load and oil viscosity. (l!S7) Read the predetermined height of the sheet using the number of pulses input into the electronic fixed memory, compare it with the actual value of the number of pulses, and use the polarity of the difference and the difference value to determine the sheet position. A method for automatic control of distance control has been devised in Japanese Patent Application Laid-Open No. 54-30696. This method links the rotation of the drive motor with a pulse generation mechanism, and uses a comparator circuit to control the addition, subtraction, etc. necessary for distance control. Compared to the control side, the detection configuration is complicated and the error is large.The comparator circuit compares the voltage by the number of pulses and replaces it with the voltage once, so the circuit configuration is complicated and it is vulnerable to external interference signals, making it difficult to put into practical use. Not enough notes.

In addition, the comparator circuit for voltage comparison requires an expensive encoder or servo motor to maintain electrical characteristics of a potentiometer, etc., in order to maintain parameters for comparison at the time of reuse when the device is stopped or the power is cut off during use. The disadvantages include that it is necessary and expensive. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a device for controlling the position of a table or chair, which overcomes the problems of the prior art described above. According to the device of the present invention, automatic control is performed in a completely non-contact manner without including any mechanical contact member in the control device;
Because we use pulses with a relatively narrow pulse width and narrow directivity as the medium for position measurement control, it is possible to make highly accurate measurements at relatively short distances, as well as when there is a relative linear motion relationship. The first that can be converted into linear motion
It can be widely applied to control the distance between the first member and the second member, the position can be controlled without changing the structure of a conventional table or chair, and it can be continuously set to a desired position. It becomes possible to generate distinctive profits such as . The present invention will be explained in more detail with reference to the drawings below. Fig. 3A is an explanatory diagram showing the transmission state of the ultrasonic pulse used in the present invention, and Fig. 3B is a conventional ultrasonic pulse waveform diagram. , Figure C is a waveform diagram of the ultrasonic pulse of the present invention, Figures D and E are longitudinal cross-sectional views of the wave transmitting device and the wave receiving device used in the present invention, and Figure 4 shows the control principle of the device of the present invention. 5 is a time chart of FIG. 4, FIG. 6 is a circuit diagram corresponding to FIG. 4, and FIG. 7 is an explanatory diagram showing another embodiment of the present invention.

In FIGS. 1 and 2, 13 is an ultrasonic pulse transmitter attached to the lower surface of the seat 5, and 14 is the transmitter 1.
3 are preferably ultrasonic pulse receivers fixed to the base 3 with their main axes substantially aligned and facing each other in a straight line, and these transmitter/receivers 13 and 14 are for controlling the position of the seat 5. belongs to.

Similarly, reference numerals 15 and 16 indicate an ultrasonic pulse transmitting device and a wave receiving device for controlling the tilting position of the back seat 9. They are placed facing each other. 1
7 is a control box whose main body is built into the backrest 9, as shown in FIG.
7 includes an ultrasonic pulse generating section 30, a receiving pulse generating section 40, a position setting section 50, a position detecting section 60, and a logic control section 70 for raising and lowering the seat and for tilting the backrest, which will be described later. It consists of 18, 19, 2
0 and 21 are setting dials for manually setting the positions of the seat 5 and backrest 9;
is a setting dial dedicated to raising and lowering the seat 5, 19 and 21 are setting dials dedicated to tilting the backrest 9, and setting dials 18-19
, 2021 form a pair.

Setting dials 18, 19, 20 and 21 are adapted to allow the positions of the seat 5 and backrest 9 to be set continuously. 22 is a command button box whose main body is built into the back seat 9 like box 17, and 23 is a press operation switch for controlling the seat 5 and backrest 9 to the positions set by the setting dials 18-19. , 24 are push-operated switches whose positions are controlled in correspondence with the setting dials 20-21.

The lifting and lowering of the seat 5 and the tilting of the backrest 9 are carried out by the hydraulic tilting mechanism 6 as described above, and these are controlled by foot movements by the hood pedal device 12 and by the above-mentioned operation switch 2.
It consists of two types of combinations of press-type automatic control by means 3 and 24, and each control is selectively performed by means not shown. Next, details of the lifting control of the seat 5 and the tilting control of the backrest 9 with respect to the seat 5 by the above device will be explained below.This control can be roughly divided into transmission of ultrasonic pulses, position setting based on these pulses, and measurement. It can be divided into two types: position control based on the results of
The details will be explained in this order.

[0 Transmission of ultrasonic pulses: Conventionally, various methods have been proposed for using ultrasonic waves underwater as measurement or communication means. Regarding the method of using this as a transmission signal to mechanically control the position between two movable members in a non-contact manner, it is difficult to put it into practical use due to technical constraints for the reasons explained below. Katta.

7' That is, (1) When the wave transmitting device and the wave receiving device are installed close to a mechanical structure (actually, this is the case in most cases).

) Since the transmission area in which ultrasonic pulses are transmitted in the air is limited by the mechanical structure, reflected waves are superimposed on the transmitted waves, making accurate ultrasonic pulse transmission difficult. (2) When the wave transmitting device and the wave receiving device are installed at a short distance and in an environment with many obstacles, standing waves tend to occur and accurate ultrasonic pulse transmission is difficult.

(3) Ultrasonic waves must be transmitted while both the transmitter and receiver are moving, and air fluctuations caused by movement, vibrations from the mounting surface, natural convection, etc. are detected as external noise. However, since the ultrasonic pulses are superimposed on the ultrasonic pulses transmitted in the air, accurate ultrasonic pulse transmission has been difficult.

To explain in more detail, FIG. 3B is an explanatory diagram showing the outline of an ultrasonic pulse generated by a single drive pulse from a piezoelectric element of a conventional ultrasonic wave transmitter. When a driving pulse is applied to the tool via a pulse transformer, the piezoelectric element is greatly excited by the piezoelectric effect, and the piezoelectric element emits an ultrasonic pulse of a constant frequency (FO) into the air due to its resonance characteristics. The ultrasonic pulse emitted by the piezoelectric element exhibits a large excitation when the driving pulse is applied to the piezoelectric element, but even after the driving pulse disappears, there is still a long aftershock. Because the vibration propagates through the case with a slight delay from the vibration of the surface, wraps around the front end surface, and interferes with it, it is not practical to emit ultrasonic pulses with good damping characteristics corresponding to the drive pulse and a narrow directivity angle. It was considered difficult.

In other words, a conventional wave transmitter emits ultrasonic pulses, and a wave receiver with the same structure as the wave transmitter is installed oppositely within a short distance.
Furthermore, if there is an obstacle near the transmitter or receiver, the ultrasonic pulses emitted from the transmitter will be received by the receiver, and some will be reflected by the obstacle and transmitted. Returned to wave gear. At this time, if the wave transmitting device is in aftershock, standing waves are generated by the reflected waves and aftershocks, which interfere with ultrasonic pulse transmission. Also, it is known that the directivity angle can be narrowed by using a thick transducer as a characteristic of ultrasonic waves, but with the conventional casing method, the vibration of the rear end of the thick transducer lags slightly behind the vibration of the front end, causing the case to collapse. It propagates around the front end face and interferes, destroying the original directivity angle of the thickness transducer and making it difficult to emit narrowly directional ultrasonic pulses. It was difficult to use it in environments restricted by structures. Alternatively, currently, as a device that uses ultrasonic waves between a transmitting device and a wave receiving device in the air, a device that detects air fluctuations or interruption of ultrasonic waves between the transmitting device and the wave receiving device has been put into practical use. ing. In the above-mentioned wave transmitting device and wave receiving device, in order to obtain gain, that is, to make maximum use of the piezoelectric effect, the capacitance of the piezoelectric element is increased to perform wave transmission with a large capacitive load. On the other hand, because the mechanical Q is low, it is disadvantageous to unnecessary radiation other than limited frequencies, and air fluctuations due to movement, vibrations from the mounting surface, natural convection, etc. are detected as external noise, and when used It has been difficult to accurately transmit ultrasonic pulses over the air as they are superimposed on ultrasonic transmission signals. Next, the ultrasonic pulse transmitting device (13, 15...hereinafter only 13 will be taken) and the wave receiving device (14, 16...
In the following, only 14 will be taken). Since both of them have exactly the same cross-sectional structure and their front ends are arranged in a relationship facing each other on one straight line, the wave transmission is done in order to avoid duplication of explanation. Only tool 13 will be described.

In FIG. 3D, the wave transmitting device 13 is a thickness vibrating piezoelectric element 1.
31 except for the front end face is surrounded and sealed with a vibration absorbing member or vibration damping member 132, and the rest except for the front outer circumference of this member 132 is fitted in contact with a casing 133, and the acoustic conductivity is A front cover 135 having a good front protective thin film 134 is fitted onto the front outer periphery of the absorbing member or braking member 132 in contact with the casing 133, and the front cover 135 is provided with a good front protective thin film 134 and the front end surface of the piezoelectric element 131. An adhesive layer 136 with good acoustic vibration transmission properties is interposed between the two, and a vibration damping adhesive layer 137 is interposed at the boundary between the casing 133 and the front cover 135. 138 is a lead connected to the electrode 1380, and 139 is a lead connected to the electrode 1390, respectively. In the illustrated example, a rear surface treatment layer having vibration absorbing or vibration damping properties and sealing properties is provided in contact with the rear surface member 1331 of the casing 133. 1332 is provided.

Next, each of the above constituent members will be explained in detail.
The thickness vibrating piezoelectric element 131 is a known cylindrical piezoelectric element, and its material and shape are not particularly new. The vibration absorbing member or vibration damping member 132 absorbs the radial vibration generated in the diametrical direction of the piezoelectric element 131 and the vibration damping member 132.
It is for primarily absorbing or damping thickness vibrations generated from the rear surface of the piezoelectric element 131 and for supporting the piezoelectric element 131, and is made of polyurethane foam, other plastic foam, glass fiber, or the like.

The casing 133 supplementally absorbs vibrations in the radial and thickness directions that could not be absorbed by the absorbing member or braking member 132, mechanically reinforces the member 132, and transmits external vibrations to the inside. It is made of, for example, polyacetal resin or other hard plastics. The front cover 135 covers the front surface of the element 131 with its front protective thin film 134 to prevent moisture from entering the inside, and also surrounds the exposed front outer periphery of the absorbing member to cover the casing. 133
The protective thin film 134 vibrates in resonance with the thickness vibration radiated from the front surface of the piezoelectric element 131, vibrates the air in front, and facilitates the generation of aerial ultrasonic waves due to the thickness vibration. belongs to. The material is preferably selected from polystyrene and other high polymer soft plastics. The vibration-transmitting adhesive layer 136 is for adhering the element 131 to the thin film 134 while allowing vibration, and is selected from adhesives that do not absorb vibration. The vibration damping adhesive layer 137 is attached to the front cover 135 and the casing 1.
Vibration absorbing member or braking member 1 with the function of adhesion with 33
The vibrations that could not be absorbed by the casing 13
This is to absorb vibrations so as not to cause radiated vibrations that cause so-called "wrapping" that interferes with the thickness vibrations transmitted through 3 and radiated from the front end surface of the element 131.In order to emit narrowly directional ultrasonic waves, It is inevitable.

The adhesive layer 137 in the figure is represented as a kind of stepped flange ring whose diameter can be increased stepwise in the diameter direction of the element 131, and silicone rubber or other viscoelastic rubber adhesive is preferably used as the material. The rear surface treatment layer 1332 cooperates with the rear surface member 1331 of the casing 133 to sufficiently block thickness vibration from the rear surface, and
8,139, and the material is bituminous material such as tar pitch.

However, it is not necessary to use this treatment layer if the casing 133 can sufficiently absorb or damp vibrations and the suspension doors 138 and 139 can be properly sealed. The wave receiving device 14 has exactly the same structure as above, so the third
As shown in FIG. Therefore, the ultrasonic wave transmitting device 13 and the wave receiving device 14 having the above structure have the following features. (1)' Because the casing 133 and the front cover 135 are acoustically separated by the vibration damping adhesive layer 137, the casing 13
The radiated vibrations transmitted from 3 have become so small that they can be ignored in practical terms, making it possible to emit narrowly directed ultrasonic pulses.

That is, the transmission area where the ultrasonic pulse is transmitted has the same structure as the spatial area where the wave transmitting device 13 emits ultrasonic pulses with a narrow directivity angle, and is opposite to the wave transmitting device 13. The spatial region shown by Ax in FIG. 3, which fills the entire region in which the installed wave receiver 14 can sense the emitted ultrasonic pulses, can be extremely narrow. Therefore, even if the wave transmitting device 13 and the wave receiving device 14 are installed close to a mechanical structure, accurate ultrasonic pulse transmission is possible as long as there are no obstacles between the wave transmitting device 13 and the wave receiving device 14. (In order to absorb the after-vibration of the piezoelectric element 131 by the 2Y vibration absorbing member or vibration damping member 132, a driving pulse is applied to the piezoelectric element 131 in the wave transmitting device 13, as shown in FIG. 3C. By vibrating the piezoelectric element with a large amplitude for the first cycle and making the time constant of the envelope of the subsequent damped vibration of the piezoelectric element 131 small, the wave transmitting device 13 and the wave receiving device 14 are
Ultrasonic pulse transmission is now possible without being affected by standing waves even if the device is installed at close range and in an environment with many obstacles.

(3Y In the wave transmitting device 13 and wave receiving device 14 having the above structure, the minimum necessary ultrasonic output to reach the distance to be actually controlled is obtained, and piezoelectric elements with high mechanical Q are used. Therefore, it became insensitive to frequencies other than limited frequencies.

Therefore, accurate ultrasonic pulse transmission is possible without sensing air fluctuations, vibrations from the mounting surface, natural convection, etc. as external noise. From what has been described above, the structure of the ultrasonic wave transmitting device 13 and the wave receiving device 14 of the present invention and the transmission method of narrow directional ultrasonic pulses that are effectively transmitted in the air between the wave transmitting device 13 and the wave receiving device 14 are as follows. It became clear. In the control method described below, in order to simplify the explanation, a case will be described in which the distance 1 between the movable wave transmitting device 13 and the movable wave receiving device 14 is controlled.

Control principle: The control principle of the present invention will be explained. 4 is a block diagram for carrying out the present invention, FIG. 5 is a timing chart of FIG. 6, and FIG. 6 is an electric circuit diagram more specifically showing the block diagram of FIG. 4. It is.

In FIG. 4, the configuration of the electric circuit for implementing the present invention is an ultrasonic pulse generation circuit section 30, an ultrasonic pulse reception circuit section 40, a setting pulse generation circuit section 50, a position determination control circuit section 60, and a drive circuit section 70. It consists of To roughly explain the operating principles of these circuits according to the marks, the ultrasonic pulse generation circuit section 30 is connected to the periodic trigger pulse generation circuit 31.
The trigger pulse as shown in Fig. 5a generated by
The ultrasonic pulse drive circuit 32 is switched, thereby applying a voltage as shown in FIG. Ultrasonic pulses as shown in FIG. 5c are emitted from the tool 13.

The ultrasonic pulse emitted by the above method is amplified, detected, and waveform-shaped by the ultrasonic pulse reception amplification and detection circuit 41 and waveform shaping circuit 42 as shown in FIG. The signal is input to the latch circuit 61 of the determination control circuit section 60. The setting pulse generating circuit section 50 is configured so that the time constant of the multi-vibrator 502 can be varied by changing the external resistor 503 of the multi-vibrator 502 using the setting dials 18, 19, 20, and 21. When the switch 23 is turned ON, the command circuit 52 issues a command signal as shown in FIG.
The transistor 504 is energized, and the two inputs of the position determination control circuit section 60 are generated as a setting pulse (h in FIG. 5) which is generated with a delay of the time constant of the external resistor 503 after the generation of the trigger pulse (a in FIG. 5). The signal is input to a match comparison circuit 63 composed of a NAND gate. In the case of FIG. 6, the press operation switches 23, 24, 25 for generating setting pulses are 3
Although only one switch is shown, it is also possible to install a plurality of switches if desired. In addition, in FIG. 6, the three push-operated switches 23, 24, and 25 are simultaneously
It is configured so that no more than one person works. It can be easily inferred that when a plurality of push-operated switches are installed, the type of control corresponding to the number of push-operated switches becomes possible. In the following description, in order to simplify the explanation, only the press-operated switch 23 will be used.

Next, details of the position determination control circuit section 60 will be explained.
The position determination control circuit section 60 is the position determination circuit 6 in the example diagram.
41 latch circuit 61, rising differential pulse generation circuit 62, 2
It consists of a coincidence comparison circuit 63 composed of an input NAND gate, and the reception pulse detected by the wave receiver 14 (FIG. 5f) and the error generated by the setting pulse generation circuit section 50 are The system is configured to input setting pulses as shown in FIG. 5h indicating positions set by the user, detect the order in which these pulses are input, and perform desired control.

When the received pulse is input, the latch circuit 61 raises its [H] level output to the differential pulse generation circuit 6.
2 and its "L" level output to JKF/F.
Each time a trigger pulse (FIG. 5a) is inputted to the K input terminal of a determination circuit 641, the output is inverted as shown in FIG. 51. Therefore, even if noise is input to the wave receiving device 14 after the received pulse (FIG. 5f) is input, its output will maintain the above-mentioned latched state and will not malfunction due to noise. The rising differential pulse generating circuit 62 generates a coincidence detection pulse shown in FIG. 5k having the same width as the setting pulse (FIG. 5h) at the rise of the "H" level output of the latch circuit 61. The judgment circuit 641 is composed of a JK input terminal, and is configured so that the output of the latch circuit 61 is inputted to the J input terminal and the K input terminal, respectively, and the setting pulse (h in FIG. 5) is inputted to the CK input terminal. . The coincidence comparison circuit 63 is composed of a two-input NAND gate that receives the setting pulse and the coincidence detection pulse as input, and when the setting pulse and the coincidence detection pulse are input simultaneously, R-
It is input to the R input terminal of the S latch circuit 642. The R-S latch circuit 642 operates when the circuit shown in FIG. 6 starts operating, that is, when the power of the circuit shown in the example is input.
It is configured so that it is initially reset and fixed at the output "L" level. Control signal command circuit 643
When the press operation switch 23 is not operated or the distance between the wave transmitting device 13 and the wave receiving device 14 matches the distance set by the user, the setting pulse and the coincidence detection pulse are simultaneously input to the comparison coincidence circuit 63. output signal M,
n is set to the "L" level, and when the press operation switch 23 is turned on, the Q of the determination circuit 641 is
It selects a signal determined by the output as appropriate and outputs the signal necessary for control. How the position determination control circuit section 60 configured as described above operates in response to input signals from the outside and performs the intended position control is explained in detail in the wave transmitting device 1.
3 and the wave receiving device 14 are shorter than the set distance desired by the user, as an example, and a more specific explanation will be given.

However, in the following description, in order to facilitate understanding of the present invention, it is assumed that the wave receiving device 14 is fixed and only the wave transmitting device 13 is movable, and the m signal is transmitted by separating the wave transmitting device 13 from the wave receiving device 14. This is a drive signal to the boost drive circuit 71 for The n signal is a drive signal to the lower drive circuit 72 for moving the wave transmitter 13 closer to the wave receiver 14. Furthermore, in practice, the wave transmitting device 1 moves two movable members and detects the facing distance L between them.
The distance L between the movable members described above is controlled by knowing the distances between the wave transmitting device 13 and the wave receiving device 14. explain. When the power is turned on to operate the circuit in the example diagram, R-
The S latch circuit 642 is initially reset as described above and holds its output at the "L" level.

Therefore, an "L" level signal is input to each of the two NAND gates of the control signal command circuit 643, and the output of the control signal command circuit 643 remains "L" as before the power was turned on.
'' level is maintained, and as a result, the distance L between the wave transmitting device 13 and the wave receiving device 14 is also maintained in the same state as before the power was turned on. Next, after the ultrasonic pulses emitted from the wave transmitting device 13 are periodically received by the wave receiving device 14, the push operation switch 23 is activated.
When inputting the JK input, the setting pulse shown in FIG. As shown in FIG. 1, an "H" level signal is outputted from the Q output terminal of.

This "H" level output is generated by the control signal command circuit together with the "H" level signal which the R-S latch circuit 642 inverts and outputs in response to the command signal as shown in FIG. The input signal is input to two NAND gates of 643, and a day/month level signal is generated at the m output terminal of the control signal command circuit.

Therefore, the raising drive circuit 71 is energized by this m output signal, and the wave transmitting device 13 is driven upward so as to be further separated from the wave receiving device 14. While the wave transmitting device 13 is being driven upward by the m signal so as to be separated from the wave receiving device 14, the trigger pulse is repeatedly emitted, and each time the wave receiving device 14 receives the received pulse as a received pulse. The order in which the coincidence detection pulse (FIG. 5h) indicating the arrival of the signal and the setting pulse generated by the trigger pulse are input is repeatedly determined, and as a result, the distance between the wave transmitting device 13 and the wave receiving device 14 is determined. When L matches the setting distance desired by the user, the setting pulse and the coincidence detection pulse are simultaneously input to the NAND gate of the coincidence comparison circuit 63, as shown in FIG.
The AND gate outputs an “L” level signal, and as a result, R
- Invert the output of the S latch circuit 642 to "L" level,
The "H" level signal shown in FIG. 5m outputted by the control signal command circuit 643 is inverted to "L" level. Therefore, the m signal to the lift drive circuit 71 is deenergized, the distance L between the wave transmitting device 13 and the wave receiving device 14 is controlled to the distance desired by the user, and the control operation is completed. If the actual distance L between the wave transmitting device 13 and the wave receiving device 14 is longer than the set distance desired by the user, it is easy to infer that the step-down drive circuit 72 is input and control is performed using the same principle as above. will be done. Therefore, a wave receiving device 14 is installed on the base 3 of the pedestal 5 shown in FIG. In controlling the lifting and lowering of a chair or a stand equipped with a wave transmitting device 13 having a structure, for example, the actual height of the seat 5 is determined by the driving m signal from the position determination circuit 641 to be lower than the height set by the user. is low, the user presses the push operation switch 23 of the command circuit 52.
By pressing , the lift drive circuit 71 is energized and the seat 5 is moved upward by the operating device connected to it, and when the height of the seat 5 reaches the height set by the user, the above-mentioned match is reached. It will be easily understood that the output signal of the comparison circuit 63 stops the above-mentioned upward movement and the control is completed, and if the height of the seat 5 is higher than the height set by the user. It can be easily inferred that the step-down drive circuit 72 is energized and control is performed based on the same principle as described above. In addition, the output terminal 7 of the up drive circuit 71 and the down drive circuit 72
It goes without saying that 3 and 74 are incorporated in parallel into the existing lifting and lowering and driving circuit of the treatment table 1. The above position control describes the elevation control of the base 3 and the seat 5, but regarding the tilt control of the seat 5 and the backrest 9, the wave transmitter 15 is attached to the fixed part 70 of the hydraulic mechanism 6. The wave receiver 16 is attached to the cylinder shaft 7 (movable part) with its respective main shaft.
4. If the wave transmitting/receiving devices 15 and 16 are placed almost in alignment and facing each other,
Since the relationship of opposing distance on a straight line is always kept constant regardless of the elevation of the seat 5, the mutual expansion/contraction distance between the wave transmitters 15 and 16 is proportional to the tilt angle of the backrest 9 with respect to the seat 5. It will be understood without explanation that the above-mentioned tilting control is performed by maintaining a constant relationship and controlling the wave transmitting/receiving devices 15 and 16 with respect to each other.

The description is merely an explanation of the device of the present invention using one dental treatment table as an example, and the device is not limited to this example but has many uses, such as applications other than dentistry. If the wave transmitter/receiver device is attached at an appropriate location on a medical treatment table (including an operating table), a barber chair, a beauty chair, or other transportation lifting device (hereinafter referred to as a ``chair treatment table, etc.''), facing each other at a relatively short distance, It is advantageously applied to position control of movable parts such as these chairs and treatment tables. Further, in the structural description of the above example, the relative relationship and position of the wave transmitting device and the wave receiving device, the setting positions of the push operation switch, the control box, etc. can be arbitrarily changed.

In addition, as shown in FIG. 7, as another embodiment of the device of the present invention, when controlling the height H during the movement up and down by the pantograph mechanism P, the transmission/reception is carried out at the location indicated by the dotted line. It is sufficient to make the corrugations face each other in a straight line, but if this is not possible for some reason, as shown in the figure, between the four links P3 and P5 that extend and contract up and down, and between the links P4 and P6. By arranging the wave transmitting tool 13 and the wave receiving tool 14 oppositely on the horizon, the height H can also be controlled by adjusting the distance between the two tools 13 and 14.

According to the description, according to the device of the present invention, automatic control is performed in a completely non-contact manner without including a mechanical contact member in the control device, and because ultrasonic pulses are used as a medium for position measurement control, Being able to perform highly accurate measurements;
The present invention can be widely applied not only to cases in which there is a relative linear motion relationship, but also to distance control between a first member and a second member that can be converted into linear motion, and to make changes to the structure of a conventional table or chair. It should be understood that the present invention brings about unique advantages such as being able to control the position without any need for control, and being able to control the desired position continuously.

Ku! Brief description of aspects Figure 1 is a front view of an example of a dental treatment table including the device of the present invention, Figure 2 is a plan view of the same, and Figure 3A is a diagram of narrow directional ultrasound used in the present invention 1. An explanatory diagram showing the pulse transmission state. Figure B is a conventional ultrasonic pulse waveform diagram, Figure C is an ultrasonic pulse waveform diagram of the present invention, and Figures D and E are the wave transmitting device and wave receiving device used in the present invention. 4 is a block diagram showing the control principle of the device of the present invention, FIG. 5 is a time chart of FIG. 4, and FIG. 6 is a circuit diagram corresponding to FIG. 4. FIG. 7 is an explanatory diagram showing another embodiment of the present invention.

Claims (1)

[Claims] Directly or indirectly disposed between a first member and a second member in a relationship that changes the facing distance by relative linear motion in one chair or chair. , an ultrasonic wave transmitting device and a wave receiving device that are opposed to each other on a straight line, and an ultrasonic pulse generator that periodically excites the wave transmitting device in a time-limited manner;
a receiving pulse generating section that generates a receiving pulse based on the ultrasonic pulse received by the wave receiving device; a position setting section that generates a setting pulse obtained by converting the distance of the ultrasonic pulse to a desired setting position into a time; a position detection circuit unit that compares the received pulse with the set pulse and determines the time difference between the two; and an operation switch unit provided on the table or chair; a logic control section that provides an operation output to a drive section of the chair; and by operating the operation switch section, one or more of the first and second members is operated according to a signal from the position setting section. An aerial ultrasonic position control device for a table or chair, which is configured to automatically drive both to their set positions and stop the driving when the time difference of the position detection circuit section becomes zero. 2. The first member is a base of a chair or table for dental, medical, barber, beauty, etc., and the second member is a seat that is movable up and down by a lifting mechanism on this base, 2. The device according to claim 1, wherein the wave transmitting device and the wave receiving device are provided directly or indirectly between the base and the pedestal. 3. The first member is a pedestal for a dental, medical, barber, or beauty chair or pedestal, and the second member is a backrest that is tiltable with respect to the pedestal by a tilting mechanism. and the wave transmitting device and the wave receiving device are provided indirectly with respect to the first and second members between the telescopic movable part and the fixed part of the tilting mechanism that tilts the backrest. The device according to item 1. 4. The device according to claim 1, wherein the first member and the second member are arranged in one or more sets. 5. The first member is a base of a table or chair for dental, medical, barber, beauty, etc., and the second member is a seat that is movable up and down by a lifting mechanism on this base, The wave transmitting device and the wave receiving device are indirectly provided between the base and the pedestal, and another first member is a pedestal of a chair or pedestal for dental, medical, barber, beauty, etc. and another second member is a backrest that is tiltable with respect to the seat by a tilting mechanism, and the wave transmitting device and the wave receiving device are telescopic movable parts of the tilting mechanism that tilts the backrest. 5. The device according to claim 4, wherein the device is indirectly provided between the first and second members and the fixing portion. 6. The telescopic movement distance of the wave transmitting device and the wave receiving device provided between the base and the pedestal is equal to that of the base and the pedestal, and the distance of the telescopic movement of the wave transmitting device and the wave receiving device provided between the base and the pedestal is equal to that of the base and the pedestal, and the device is provided between the telescopic movable part and the fixed part of the tilting mechanism. 6. The device according to claim 5, wherein the distance of expansion and contraction of the wave transmitting device and the wave receiving device maintains a constant relationship with the tilting angle of the backrest with respect to the seat. 7. The first member is a base of a dental, medical, barber, beauty, etc. chair or stand, and the second member is a seat that is tiltable by a tilting mechanism on the base. An apparatus according to claim 1.