JPS6249690B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pneumatically responsive waterproof pressure switch that opens and closes an electric switch member based on changes in air signal pressure relative to atmospheric pressure.

Conventionally, in this type of pressure switch, the electric switch member is placed in an atmospheric chamber that introduces the atmosphere, so moisture, dust, etc. that enter with the atmosphere can damage the switch member and prevent it from functioning properly. Measures are taken to prevent the loss of information. Regarding this prevention device, the present applicant has already filed an application for one in which the atmospheric chamber side is sealed with a flexible cover that is thin and has pleats, and the volume of the atmospheric chamber side can be increased or decreased by deformation of the pleats. However, the present invention also belongs to this type of form, and the present invention aims to further improve its functionality and ensure ease of assembly.

Embodiments of the waterproof pressure switch of the present invention will be described below with reference to the drawings.

FIG. 1 shows a type of pneumatic responsive waterproof electric switch in which vacuum (negative pressure) is used as the air signal pressure.

A casing is constituted by a first housing 1 and a second housing 2, and a diaphragm 3 that is airtightly sandwiched between the two causes a signal that a vacuum signal pressure is introduced from an input signal port 4 to one side inside the casing. A pressure chamber 5 is formed, and an atmospheric pressure chamber 6 into which the atmosphere is introduced is formed on the other side.

Inside the atmospheric pressure chamber 6, a terminal with a fixed contact 7, which is an electric switch member, is connected to a second terminal by a screw 8.
One bent end of a movable contact 10, which is an electric switch member, is fixed to a terminal 9 fixed to the housing 2 and fixed with a screw 8', and the other end is arranged so as to be able to come into contact with and separate from the fixed contact 7. .

Reference numeral 11 denotes a pressure plate that is engaged with the center of the diaphragm 3 and also engages the center of the movable contact 10. A spring 14 is tensioned between the pressure plate 11 and a retainer 13 supported by a spring pressure adjustment screw 12 screwed into the first housing 1. The movable contact 10 is brought into contact with the fixed contact 7, and the electric switch member is closed. Lead wires 1 electrically connected to terminals 7 and 9, respectively
5 and 16 are clamped to the second housing 2 by a support member 17 that supports a flexible cover, which will be described later. The support member 17 has a concave hole 17a (oval shape in the illustrated example) that receives the flexible cover in its central protrusion and exhibits a rotation prevention effect, and an appropriate number of mounting legs 17b. It is inserted and coupled into the engagement hole 2a of the housing 2 in a snap fit manner.

Reference numeral 18 is a flexible cover made of rubber material, and has an oval base 18a and thin folds 18b concentrically, forming an outer periphery flange 18c.

As can be seen in the figure, this flexible cover 18 airtightly sandwiches the lead wires 15 and 16 within its base 18a, and the base is connected to the recessed hole 1 of the support member 17.
It is inserted and supported by 7a.

The flange portion 18c is hermetically engaged with the flange recess 2b portion of the second housing 2.

Further, 19 is a chamber communicating with the atmospheric chamber 6 formed by the second housing 2 and the flexible cover 18;
0 is a cover that is coupled to the second housing 2 in a snap-fit manner and presses down on the flexible cover 18.

The waterproof pressure switch of the present invention is constructed as described above, and its operation will be described below.

When the vacuum signal pressure (vacuum pressure relative to atmospheric pressure) introduced from the input signal port 4 to the signal pressure chamber 5 is lower (in the direction of atmospheric pressure) than the set pressure set by the biasing of the spring 14, the diaphragm 3 and the Tsusha plate 11 is spring 1
4, the movable contact 10 is displaced to the illustrated position.
contacts the fixed contact 7, and the electric switch member is switched closed. Next, when the vacuum signal pressure introduced from the input port 4 into the signal pressure chamber 5 is higher than the set pressure (in the vacuum direction), the diaphragm 3 and the pressure plate 11 are moved from the illustrated position against the bias of the spring 14. The movable contact 10 is disengaged from the fixed contact 7 due to the leftward displacement of the pressure plate 11, and the electric switch member is switched open. If there is a change in the temperature around the vacuum response electric switch, for example if the temperature rises from room temperature, the flexible cover 18 will be affected by the expansion due to the expansion of the atmosphere as the temperature of the atmospheric chambers 6 and 19 increases. Accordingly, the pleat portion 18b deforms in the direction of protruding to the right in the figure, and the volume of the chamber 19 increases and changes in accordance with the expansion of the atmosphere in the atmospheric chamber 6 and the chamber 19 due to the rise in temperature. is maintained at atmospheric pressure.

For example, if the ambient temperature of the vacuum response electric switch falls from room temperature, the atmospheric chamber 6 and the chamber 19
Due to the contraction of the atmosphere as the temperature decreases, the pleats 18b of the flexible cover deform to the left in the figure in response to the contraction, thereby maintaining the atmospheric chambers 6 and 19 at atmospheric pressure. Therefore, the vacuum-responsive electric switch has a vacuum-responsive electric switch, since the air in the sealed atmospheric chamber side 6 is maintained at atmospheric pressure by the deformation of the flexible cover 17 in response to changes in ambient temperature. A predetermined opening/closing switching operation can be performed using the set value of the signal pressure.

In the structure of the waterproof member in the present invention, in order to ensure ease of assembly and improve functionality, the base 18a (illustrated oval type) of the flexible cover 18 is received 17a to prevent relative rotation. A protectively coupled support member 17 is snap-fitted to the second housing 2 and is also attached to the collar 1 of the flexible cover.
8c is pressed onto the airtight recess 2b of the second housing by the cover 20 in a snap-fit manner. This means that during operation, the flexible cover base 18a does not deviate outward from the center due to temperature fluctuations in the chamber 19, and is always kept at the center position, allowing the predetermined valve switching operation to be carried out. No negative effect on pressure. Moreover, its assembly and arrangement can be performed reliably and easily. Moreover, the flexible cover 18 is
The flange 18c can be easily and closely attached to the second housing 2 around the assembled base, and is covered by the snap fitting of the cover 20, so it can replace the conventional one for the same purpose. Compared to the provided device means, it has great advantages in terms of function and assembly.

In this embodiment, a support member is provided to receive the flexible cover and clamp the lead wire, but a clamp member for the lead wire is provided separately, and the flexible cover receiving portion is integrated into the second housing. It is also possible to provide a

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the waterproof pressure switch of the present invention, FIG. 1-1 is a view taken in the direction of the arrow A-A in FIG. 1, and FIG. It is an enlarged explanatory diagram. 1...First housing, 2...Second housing, 3...Diaphragm, 5...Signal room, 6...
Atmospheric pressure chamber, 7...Fixed contact, 9...Terminal,
10... Movable contact, 11... Pressure plate, 17... Support member, 18... Flexible cover,
20...Cover.

Claims (1)

[Claims] 1. A casing in which a signal pressure chamber into which air signal pressure is introduced and an atmospheric chamber into which atmospheric air is introduced are airtightly partitioned by a diaphragm, and in the atmospheric chamber, a movable contact is brought into contact with and separated from a fixed contact by displacement of the diaphragm. An electric switch member is provided that operates to switch,
On one side of the casing, a support member that receives the base of a flexible cover concentrically with thin folds in a non-rotatable manner is attached in a snap-fit manner, or a base receiving portion formed integrally is attached to one side of the casing. The flexible cover receives and supports the base, and the outer edge of the flexible cover is hermetically locked to the casing to seal the atmospheric chamber side, and the volume of the atmospheric chamber side is increased by deformation of the pleats of the flexible cover. A waterproof pneumatic responsive electric switch which can be adjusted to increase or decrease, and wherein the flexible cover is press-fitted with a cover that snaps onto the casing from the outside.