JPH0778535B2 - Ultrasonic switch - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic switch, and particularly to an angle adjustment of an ultrasonic switch horn and a structure for holding the angle.

(Prior Art) As a horn angle adjusting structure in a conventional ultrasonic switch, for example, as shown in Japanese Patent Publication No. 59-32958, a sphere is provided at the rear of the horn, and a sphere receiving surface provided on a main body housing is provided. Support the rotating sphere through an elastic body,
There is one in which the horn is rotatably held in a main body housing.

By the way, in this structure, when an excessive stress is applied to the tip of the horn due to a fall of the ultrasonic switch or the like, an elastic body such as a leaf spring is pushed by the rotating ball, and this elastic body is mounted on the control circuit. The printed circuit board comes into contact with the printed circuit board to absorb the stress. Therefore, there has been a problem that excessive stress is applied to the printed board, and the printed board is cracked or the like.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, in which the stress applied to the tip of the horn is absorbed by the bottom plate instead of being absorbed by the printed plate, and the elastic body causes permanent strain. It is an object to provide an ultrasonic switch that does not receive the ultrasonic waves.

(Structure of the Invention) According to the present invention, a rotating sphere is provided at the rear of a horn and a spherical body receiving surface is provided on a main body housing, and an elastic body attached to the main body housing imparts a constant holding force to the rotating sphere on the spherical body receiving surface. In an ultrasonic switch in which the horn is rotatably held in the main body housing, the supporting base made of a member having a large friction coefficient is interposed between the rotating ball and the elastic body. Further, the printed circuit board on which the control circuit is mounted is covered with the main body housing and the bottom plate and fixed to a part of the main body housing, and the tip of the support base is kept in contact with the printed board without exceeding the stress limit of the elastic body. It is made to face the position where it can come into contact with the bottom plate at the changed position of.

With this configuration, when an excessive stress is applied to the tip of the horn, the tip of the supporting base abuts the bottom plate, and the stress can be absorbed by this bottom plate.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

A microphone (not shown) for transmitting and receiving ultrasonic waves is mounted on the rear portion of the horn 1, and a rotating ball 2 for supporting the horn 1 is provided around the microphone.

The main body housing 3 is formed with a spherical receiving surface 4 for supporting the rotating sphere 2, and an elastic body 5 made of a leaf spring or the like is attached by a screw 6, and the elastic body 5 receives the rotating sphere 2 on a spherical surface. The surface 4 is supported with a constant holding force applied, and the horn 1 is rotatably held by the main body housing 3. Further, between the rotating ball 2 and the elastic body 5, a support base 7 made of a material such as rubber having a large friction coefficient is provided.
The base of is intervened.

Further, the printed circuit board 8 on which the control circuit is mounted is covered with the main body housing 3 and the bottom plate 9 provided at the opening end of the main body housing 3, and the boss portion 3 a rising from the main body housing 3 and the bottom plate 9 are provided. It is sandwiched by the raised spacer portion 9a and fixed by a screw 10 screwed into the boss portion 3a of the main body housing from the lower side of the bottom plate 9.

Further, the support base 7 has a fitting insertion hole 8a formed in the printed board 8.
Is inserted into the printed board 8 without contacting the printed board 8, and its tip portion 7a is opposed to a position where it can come into contact with the bottom plate 9 at a changed position within the stress limit of the elastic body 5.

The bottom plate 9 is made of a conductor such as an iron plate, and the spacer portion 9a integrally formed with the bottom plate 9 is provided.
As shown in FIG. 2, it can come into contact with the grounding copper foil 8b of the circuit of the printed board 8. In addition, 8c is a screw
10 is a screw hole to be inserted, and 8d is a lead wire.

Thus, by connecting the ground of the control circuit to the bottom plate 9 made of a conductor, the ultrasonic switch can be made less susceptible to external unwanted radiation noise.

Due to the spherical receiving surface 4 of the main body housing 3 and the elastic body 5,
Due to the structure of supporting the rotating ball 2 of the horn 1, via the base of the support base 7 interposed between the rotating ball 2 and the elastic body 5,
The elastic force of the elastic body 5 pushes up the rotating ball 2, which causes the rotating ball 2 to be stressed, and thus the direction of the horn 1,
The angle can be set arbitrarily, and the orientation of the detection area of the ultrasonic switch can be freely changed.

Now, in the above structure, when an excessive stress is applied to the tip of the horn 1 from the outside, the elastic body 5 is pushed downward on the rotating ball 2 and the support base 7 in contact with the rotating ball 2 is moved downward. Pushed by. At this time, the stress applied to the tip of the horn 1 does not cause permanent deformation of the elastic body 5 at the displacement of the elastic body 5 within the stress limit and the tip of the support base 7 abuts on the bottom plate 9. It will be dispersed and absorbed by the screw portion fixing the bottom plate 9.

Further, at this time, the support base 7 has the insertion hole 8a of the printed board 8
Since the printed board 8 is fitted without being in contact with the printed board 8, no stress is applied to the printed board 8.

FIG. 3 shows an example of a circuit block configuration of the ultrasonic switch.

In the figure, the integrator circuit (I) 11 starts integration at the same time when the power is turned on, and when the potential reaches a certain level, the monostable multi (I) 12 at the next stage is driven, and the monostable multi (I) is driven.
The charge integrated by the signal of 12 is discharged by the switching circuit (I) 13.

The switching circuit (I) 13 receives the signal from the monostable multi (I) 12 and discharges the electric charge accumulated in the integrating circuit (I) 11 in an instant.

The monostable multi (I) 12 receives a signal from the integrating circuit (I) 11 and outputs a signal for driving the gate 14, the switching circuit (I) 13, and the monostable multi (II) 15 for a certain period of time. To do.

The gate 14 outputs a signal to the integrator circuit (II) 24 after a certain period of time after receiving the signal of the monostable multi (I) 12, and is a so-called time gate for determining the detection distance. .

The monostable multi (II) 15 receives the signal of the monostable multi (I) 12 and outputs a signal for a certain period of time. This signal determines the application time of the microphone drive of the transducer 19. Further, this signal resets the flip-flop circuit 16.

The transmitting circuit 17 receives the signal of the monostable multi (II) 15 and
The driver 18 generates a high-frequency signal for driving the microphone for a predetermined time.
It is for creating a signal of a level necessary to drive a microphone from a high frequency signal created in.

The ultrasonic wave transmitter / receiver wave 19, which is the main body of the ultrasonic switch, emits an ultrasonic wave based on the transmission signal from the driver 18 and receives a reflected wave from the detection object 20, and has the functions of a microphone and a microphone. .

The amplification circuit 21 is for amplifying the received signal due to the weak reflection from the microphone to a certain level.
22 removes the high frequency component of the vibration frequency of the microphone of the amplified signal and extracts only the envelope of the reflected wave.The level detection circuit 23 outputs the level of the output component of the detection circuit 22 to a predetermined level. It is a circuit that determines whether or not it has reached.

The integrator circuit (II) 24 is a circuit that determines whether or not the time width of the input signal that has reached a predetermined level has a predetermined time width. If this time is shorter than a predetermined value, electrical noise or the like will occur. , It is determined that it is not the reflected wave of the detected object. Here, a gate signal is applied from the gate 14, and it is also determined whether the input wave is within a predetermined time (within the gate).

Further, the flip-flop circuit 16 is an integration circuit (II).
At 24, when there is an input wave that is judged to be in the gate due to the predetermined time width, the signal causes the flip-flop operation to store the existence of the signal.
The memory is reset by the monostable multi (II) 15 and is no longer stored when the reflected wave (input wave) disappears.

The switching circuit (II) 25 is a flip-flop circuit 16
Is for turning on the relay 26 while the memory signal is present, and the relay 26 is for driving other equipment (load).

Next, another embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the bottom plate is a conductor and the conductor is provided with a ground for the control circuit, and the ground structure is devised when the bottom plate is attached to a building as a mounting plate. Is.

That is, in FIGS. 4 to 6, the same members as those described above are denoted by the same reference numerals, the main body housing 3 is made of an insulator, and the bottom plate 9 is a mounting plate made of a conductor. Is formed with a recess 9a ', and the main body housing 3 and the bottom plate 9 are formed.
When the and are assembled, the printed board 8 is sandwiched between the boss portion 3a of the main body housing 3 and the recess 9a 'of the bottom plate 9,
Moreover, the grounding copper foil 8b of the control circuit formed around the screw hole 8c of the printed circuit board 8 is configured to electrically contact with the recess 9a 'of the bottom plate 9, and the ultrasonic switch main body is made conductive by the bottom plate 9. When attached to the construction 100 consisting of,
The structure installation screw 101 is used to electrically connect the two.

In addition, 102 is a terminal block provided in the main body housing 3, 103 is a terminal screw, and 104 is a lead wire.

The operation of the above configuration will be described. The grounding copper foil 8b of the control circuit is brought into electrical contact with the bottom plate 9 made of a conductor to provide a shielding effect against external radio noise (unnecessary radiation noise). It is possible to obtain stable operation because it becomes strong against noise.

Here, when the ultrasonic switch is directly attached to a construction made of an insulating material such as wood, it is not necessary to consider the influence of noise, but the construction to which the ultrasonic switch is attached is made of aluminum, an iron plate, or the like. When it is a conductor and it has not fallen to the ground, noise will be transmitted to the construction made of this conductor, the construction itself will become an antenna, collect unnecessary radiation noise, and the ultrasonic switch will be affected by the noise. It may be easier.

However, as in this embodiment, the bottom plate 9 made of a conductor is used as a mounting plate, and is electrically connected to the structure 100 made of a conductor with the structure installation screw 101, thereby grounding the circuit and constructing the structure 100. The building with a large area, which is electrically connected to, will have a more effective shielding effect.

Further, the structure of the support base 7 interposed between the rotating ball 2 provided at the rear portion of the horn 1 and the elastic body 5 is similar to that of the above-mentioned embodiment, and excessive stress is applied to the tip of the horn 1. The action and effect of the above are the same as described above.

(Effects of the Invention) As described above, according to the present invention, the elastic member of the elastic body can be disposed without contacting the printed board with the tip of the support base interposed between the rotating ball supporting the horn and the elastic body. Since it is opposed to the position where it can come into contact with the bottom plate at a deformed position within the stress limit, the support base should contact the bottom plate even if excessive load is applied to the tip of the horn due to the fall of the ultrasonic switch. As a result, the deformation of the elastic body can be prevented, so that there is no change in the contact pressure between the rotating sphere of the horn and the spherical receiving surface of the main body housing, and the horn angle adjustment and its angle holding function are maintained for a long period of time. In this way, it is possible to ensure stable.

[Brief description of drawings]

FIG. 1 is a side sectional view of an ultrasonic switch according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a main part of the ultrasonic switch, and FIG. 3 is a block diagram including a control circuit of the ultrasonic switch. FIG. 4 is a perspective view of an ultrasonic switch according to another embodiment of the present invention, FIG. 5 is a side sectional view of the same embodiment, and FIG. 6 is an exploded perspective view of a main part of the same embodiment. 1 ... Horn, 2 ... Rotating sphere, 3 ... Main body housing, 4 ... Sphere receiving surface, 5 ... Elastic body, 7 ... Support base, 8 ... Printed board, 8a
… Fitting holes, 9… Bottom plate.

Claims (1)

[Claims] 1. A sphere is provided with a rotating sphere at the rear of the horn and a sphere receiving surface is provided on a main body housing, and a constant holding force is applied to the sphere receiving surface by an elastic body attached to the main body housing. In an ultrasonic switch which is supported and rotatably holds the horn in a main body housing, a support base made of a member having a large friction coefficient is interposed between the rotating ball and an elastic body, and a control circuit is provided. The mounted printed board is covered with the main body housing and the bottom plate and fixed to a part of the main body housing, and the tip of the support base is not brought into contact with the printed board,
An ultrasonic switch characterized in that it is opposed to a position where it can come into contact with the bottom plate at a changed position within the stress limit of the elastic body.