JPH0416335Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Field of the invention This invention is applicable to, for example, 20 to 80 mm water column (mmH ₂
This invention relates to a pressure switch that operates at the low pressure of O) and detects gas leaks and other conditions.

(b) Background of the invention The pressure switch in the above example usually includes a pressure receiving element that expands and contracts in response to changes in fluid pressure, a plunger that moves forward and backward in conjunction with this pressure receiving element, and a contact point that moves in conjunction with the forward and backward movement of the plunger. It is equipped with an action switch that opens and closes the part, and in the action switch, the movable piece is moved by the movement of the plunger,
It controls the ON-OFF operation of the contacts. A biasing spring made of a bow spring is used as a means for pressing and biasing the movable piece in a certain direction.

Furthermore, as a locking structure for the fulcrum part of the biasing spring, conventionally, as shown in FIG.
or, as shown in FIG. 6, a locking groove 54 having a triangular cross section is provided in the fixing piece 50, and the fulcrum part 53 of the biasing spring 52 is engaged with the locking groove 54.
A locking mechanism is used.

However, if it has a trapezoidal groove shape as shown in Fig. 5,
Since there is enough room for the fulcrum portion 53 to slide between the position shown by the solid line and the position shown by the imaginary line, this allows the biasing spring 52 to move from the initial state to the operating state.
This causes rattling when the switch moves, and the characteristics of the action switch have largely fluctuated due to vibration, impact, repetitive motion, etc.

In addition, in the triangular groove shape shown in FIG. 6, in the initial state of the biasing spring 52, the fulcrum portion 53 fits and fits into the deep valley in the groove as shown in FIG. 6A, but in the operating state In this case, the contact of the fulcrum part 53 is shown in FIG. 6B.
In order to move to the downward slope 55, the biasing spring 52 has to perform a two-stage operation in which the actual fulcrum position moves from a to b, resulting in poor repeatability and vulnerability to impact. There was a problem.

(c) Purpose of the invention In view of the above-mentioned problems, the purpose of this invention is to provide a pressure switch that does not cause rattling in the action switch portion and does not cause movement of the fulcrum.

(Summary of the invention) In this invention, when pressing and urging the movable piece of an action switch in a certain direction using a biasing spring whose fulcrum part is locked to a fixed terminal, the fulcrum locking part of the fixed terminal is The pressure switch is characterized by having an inclined surface on the curved side of the biasing spring, a right-angled surface on the opposite side, and a groove shape on both sides connected by a vertical surface with a length approximately corresponding to the thickness of the bow spring. shall be.

(e) Effects of the invention According to this invention, the inside of the locking groove is shaped to be wide open in the direction of motion of the biasing spring due to the vertical and right-angled surfaces, so that the fulcrum of the biasing spring does not overlap with the inclined surface. Although the biasing spring operates from the initial state where it is locked at the intersection with the vertical plane, the fulcrum moves to the locking position between the biasing spring fulcrum and the locking groove as in the conventional example in Fig. 6. In addition, as mentioned above, the height of the vertical plane that opens the inside of the locking groove is set to approximately correspond to the spring thickness of the biasing spring. The sliding movement of the spring fulcrum portion is regulated by the right angle surface, and the biasing spring fulcrum portion is reliably retained in the locking groove by the stopper action of the right angle surface.

Therefore, there is no wobbling or spring dislodgement when the biasing spring is operated, and a switch structure that is resistant to vibrations and shocks can be achieved, and fluctuations in switch characteristics due to repeated operations can be suppressed.

Further, there is no movement of the fulcrum position of the biasing spring, and unstable operation unlike that of a two-stage snap does not occur.

(F) Embodiment of the invention An embodiment of the invention will be described below in detail based on the drawings.

The drawing shows a pressure switch, and in FIG. 2, which is based on FIG. Disc-shaped protective cap 4
A switch case 5 made of synthetic resin, a ring-shaped metal holding plate 7 attached to an annular recess 6 in the vertically intermediate portion of the switch case 5, and a pressure receiving port communicating with the pressure receiving port 3 described above. Located in room 8,
A pressure receiving element 9 that expands and contracts in response to changes in gas or other fluid pressure; A plunger 11 that moves forward and backward in conjunction with the pressure receiving element 9 and is disposed within the plunger sliding hole 10 of the switch case 5; Skirt portion 1 in switch case 5 of
By engaging the locking protrusions 14, 14 in the locking holes 13, 13, the switch base 15, which is fixed to the switch case 5, and the plunger 11, which is assembled to the switch base 15, are assembled. It is provided with an action switch 16 that opens and closes between the contact portions in conjunction with forward and backward movement.

Here, the aforementioned pressure receiving flange 1 has its lower end
It is fixed to the upper outer periphery of the holding plate 7 in an airtight manner.

Further, the aforementioned pressure receiving element 9 includes a cylindrical metal bellows 17 whose lower end is fixed to the holding plate 7, a bellows top plate 18 that seals the upper end opening of this metal bellows 17, and a tightly fixed fixation to the top surface of this bellows top plate 18. The outside of the pressure receiving element 9 is set as the above-mentioned pressure receiving chamber 8, and the inside of the pressure receiving element 9 is set as an atmospheric pressure chamber 20.

Further, an input fixed terminal 21 is formed as an insert on the right side of the switch base 15, and an output fixed terminal 22 is formed as an insert on the left side.

Then, by extending the upper end of the input fixed terminal 21 into the switch internal space 23 and bending this extended upper end in the horizontal direction, a fixed piece 24 integrally formed with the input fixed terminal 21 is attached to the upper end of the input fixed terminal 21. is forming.

The above-mentioned fixed piece 24 has its free end connected to the plunger 1.
1, and by forming an opening 25 in this extending portion, the extending end portion 26 is configured to be movable in the vertical direction.

On the other hand, the upper end of the aforementioned output fixed terminal 22 similarly extends into the switch internal space 23, and by bending this extended upper end in the horizontal direction, a fixed tongue piece 27 is integrally formed.

Further, as shown in FIG. 3, an annular movable piece 28 made of a flat plate spring and an urging spring 29 made of a bow spring and curved in an arch shape are provided.

Then, the right inner end 28a of the above-mentioned movable piece 28
is locked in the approximately V-shaped notch in the right bent portion 30 of the above-mentioned fixed piece 24, and the right end fulcrum portion 31 of the biasing spring 29 corresponds to the left bent portion of the above-mentioned fixed piece 24. A locking hole 39 (described later) of the extending end portion 26
At the same time, the notch steps 32, 32 at the left end of the biasing spring 29 are engaged with the locking part 33 inside the left side of the movable piece 28, and each of the above-mentioned elements 21
~33, the action switch 1 shown in FIG.
6.

This action switch 16 is connected to the plunger 1
Normally open, which opens and closes between the fixed contact 34 on the lower surface of the fixed tongue piece 27 (see Fig. 3) and the movable contact 35 on the left upper surface of the movable piece 28 (see Fig. 2) in conjunction with the forward and backward movements of the movable piece 28. The first switch is
In the figure, this action switch 16 is
The figure shows the ON state.

The above-mentioned plunger 11 has a fixing piece 2 at its lower part.
This is a synthetic resin plunger integrally formed with gate-shaped pushers 36, 36 that span over 4, and each of these pushers 36, 3
The lower end of the plunger 6 is brought into contact with the upper surface of the central portion of the movable piece 28, and the upper end of the plunger 11 is brought into contact with the inner surface of the bellows top plate 18 mentioned above.

Left side extending end 26 of the aforementioned fixing piece 24
A metal plate 37 is formed as an insert in the switch base 1 that faces the metal plate 37.
An adjustment screw 38 is screwed together.

This adjustment screw 38 is a screw for vertically adjusting the position of the fulcrum part 31 of the above-mentioned biasing spring 29 from outside the switch, and the upper end of this adjustment screw 38 is always connected to the bent lower end of the above-mentioned extension end part 26. It is in contact with the

By the way, the right end fulcrum portion 3 of the biasing spring 29 mentioned above
The locking groove 39 for locking 1 to the fixed piece 24 is
As shown in FIG. 1, the biasing spring 29 exhibits an inclined surface 40 on the arched side (the upper side in the drawing),
The opposite side (lower side in the drawing) presents a horizontally right-angled surface 41, and both surfaces are shaped like a groove connected by a vertical surface 42 with a height approximately corresponding to the spring thickness h of the biasing spring 29.

The fulcrum portion 31 is fitted in an initial state in which the upper corner portion of the fulcrum portion is pressed against and locked at the intersection 43 of the inclined surface 40 and the vertical surface 42.

When this pressure switch is used for gas leak detection, the pressure receiving port 3 described above is connected to the gas pipe for use.

Now, gas leakage occurs in the above-mentioned gas pipe from under the normal normally open state shown by the solid line in FIG. 4, and the pressure in the pressure receiving chamber 8 decreases, causing the When the differential pressure falls below a predetermined value, the pressure receiving element 9 moves upward due to the restoring force of the metal bellows 17, and as the pressure receiving element 9 moves upward, the above-mentioned plunger 11 moves upward.

As a result, the movable piece 28 of the action switch 16 is moved upward by the force of the biasing spring 29, and the normally open state shown by the solid line in FIG. ,
A gas leak detection current is applied through each element 21, 24, 28, 34, 22 shown in the figure.

By the way, in the initial state of the biasing spring 29, the upper corner of the fulcrum portion 31 is at the intersection 43 of the inclined surface 40 of the locking groove 39 and the vertical surface 42, as shown by the solid line in FIG.
The action switch 16 is turned ON from the initial state in which it is locked to a part and the locked part is used as a fulcrum position.
It expands with the movement, but in this case, the above intersection 43
There is no sloped surface formed in the lower part of the groove, and the inside of the groove is left wide open between the vertical face 42 and the right angle face 41, so there is nothing that comes into contact with the lower corner of the fulcrum part 31. Therefore, the movement of the fulcrum as in the conventional example shown in FIG. 6 does not occur.

Moreover, since the height of the vertical plane 42 below the intersection 43 is made to correspond approximately to the spring thickness h of the biasing spring 29, even if the fulcrum part attempts to slide as in the conventional example in FIG. The right angle surface 41 acts as a stopper and prevents the fulcrum portion 31 from moving,
This prevents the biasing spring 29 from wobbling during operation, and prevents the fulcrum portion 31 from being pulled out.

In the correspondence between the structure of this invention and the above embodiment, the contact of this invention corresponds to the fixed contact 34 and the movable contact 35 of the embodiment, and similarly, the fixed terminal is the fixed piece of the input fixed terminal 21. 24 and other parts with the same names, the present invention is not limited to the configuration of the above-described embodiment.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; Fig. 1 is an enlarged view of the locking structure of the urging spring fulcrum, Fig. 2 is a vertical cross-sectional view of the pressure switch, and Fig. 3 is a partial exploded view of Fig. 1. A perspective view, FIG. 4 is an electric circuit diagram of the pressure switch, FIG. 5 is a diagram showing an example of a locking structure of the fulcrum part of a conventional biasing spring, and FIGS. 6A and B are operation explanations showing other examples. It is a diagram. 9...Pressure receiving element, 11...Plunger, 16...
...Action switch, 24...Fixing piece, 28...
...movable piece, 29...biasing spring, 31...fulcrum part,
34... Fixed contact, 35... Movable contact, 39...
Locking groove, 40... Inclined surface, 41... Right angle surface, 42
...Vertical surface.

Claims (1)

[Claims for Utility Model Registration] A pressure receiving element that expands and contracts in response to changes in fluid pressure, a plunger that moves forward and backward in conjunction with the pressure receiving element, and an actuator that opens and closes between contact portions in conjunction with the forward and backward movement of the plunger. In pressing and urging the movable piece of the action switch in a certain direction using a biasing spring whose fulcrum part is locked to a fixed terminal, the fulcrum part of the fixed terminal is A pressure switch in which the stop part has a groove shape with an inclined surface on the curved side of the bow spring, a right-angled surface on the opposite side, and both sides are connected by vertical surfaces with a length approximately corresponding to the thickness of the biasing spring.