Pressure switch

Abstract

To provide a pressure switch that can prevent leakage of pressure medium by suppressing damage to a pressure-responsive portion.SOLUTION: A pressure switch 1 includes a bellows 3 which is a pressure-responsive portion within a main body 2, an operating plate 4 which has an insertion hole through which a fulcrum 2a provided on the main body 2 is rotatably inserted and which rotates around a fulcrum 2a as the bellows 3 expands and contracts, a spring 5 which opposes the movement of the operating plate 4, an operating shaft 6 which responds to the movement of the operating plate 4, and a movable contact plate 11 which moves a movable contact 13 towards and away from fixed contacts 12A, 12B as the operating shaft 6 operates.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure switch.

Background Art

[0002] Conventionally, as a pressure switch, there is known one including a bellows as a pressure-responsive part inside a main body, an L-shaped operating plate that rotates around a fulcrum provided on the main body as the bellows expands and contracts, a spring connected to a vertical side portion of the operating plate to oppose the movement of the operating plate, an operating shaft that responds to the movement of the operating plate, and a movable contact plate that controls a micro switch by the operation of the operating shaft (see, for example, Patent Documents 1 and 2).

[0003] In such a pressure switch, one end side of the operating shaft is engaged with a vertical side portion of the operating plate, and the other end side is engaged with a movable contact plate constituting the micro switch. The micro switch includes, for example, two fixed contacts and a movable contact disposed between them. In the micro switch, the movable contact with respect to the fixed contacts is provided at a free end portion of the movable contact plate. The movable contact plate has a rapid reversal mechanism including a deformation spring.

[0004] And in such a conventional pressure switch, when the pressure applied to the bellows increases or decreases and the operating plate rotates around the fulcrum, the movable contact plate operates via the operating shaft that responds to the movement of the operating plate. Thereby, the movable contact plate selectively connects the movable contact between one or two fixed contacts, and the micro switch is reversed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the conventional pressure switches described in Patent Documents 1 and 2, on the main body, a pressure increase side stopper that restricts the rotational movement of the operating plate and a pressure decrease side stopper (Patent Document 1 has only the latter) are provided at a predetermined interval in the vertical direction near the end portion on the lateral side portion of the operating plate. And when an excessive pressure is applied to the bellows, the operating plate is held by a fulcrum provided on the main body and a pressure increase side stopper provided above the side portion inside the main body, thereby preventing the bellows from extending.

[0007] However, in such a conventional pressure switch, when the pressure applied to the bellows becomes higher, the bellows may extend while tilting, and the operating plate of the main body may tilt. As a result, the operating plate that has lost the support relationship with the main body is pushed up by the lower bellows in a state where the end portion of the lateral side portion is tilted downward, so there is a risk that the end portion of the lateral side portion will come off from the pressure decrease side stopper and drop toward the bottom plate. In this case, the dropping of the operating plate not only causes damage to the bellows but also may cause leakage of a pressure medium such as a refrigerant.

[0008] An object of the present invention is to provide a pressure switch that can suppress damage to the pressure-responsive portion and prevent leakage of the pressure medium.

Means for Solving the Problems

[0009] The pressure switch of the present invention includes a pressure-responsive portion inside the main body, an operating plate provided with an insertion hole through which a fulcrum provided on the main body is rotatably inserted and that rotates about the fulcrum due to the expansion and contraction of the pressure-responsive portion, a spring that opposes the movement of the operating plate, an operating shaft that responds to the movement of the operating plate, and a movable contact plate that makes the movable contact contact and separate from the fixed contact by the operation of the operating shaft, and is a pressure switch having: The operating plate has a first side portion including a contact portion with which the pressure-responsive portion abuts, and a second side portion that is continuous with one end side of the first side portion via a bent portion. In the unpressurized state of the pressure switch, the contact portion is located within the range of the opening of the insertion hole in the expansion and contraction direction of the pressure-responsive portion.

[0010] According to the present invention as described above, it is possible to suppress damage to the pressure-responsive portion and prevent leakage of the pressure medium.

[0011] At this time, the insertion hole is preferably located inside the outer shape of the upper surface of the pressure-responsive portion.

Effect of the Invention

[0012] According to the pressure switch of the present invention, it is possible to suppress damage to the pressure-responsive portion and prevent leakage of the pressure medium.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0014] The pressure switch according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the pressure switch 1 of the present embodiment includes a box-shaped main body 2 that constitutes an outer shell as a case, a bellows 3 as a pressure-responsive portion disposed at the bottom of the main body 2, and an L-shaped operating plate 4 that rotates about a fulcrum 2a by the expansion and contraction of the bellows 3.

[0015] The actuating plate 4 is formed in an L shape having a vertical side portion 4a which is the second side portion and a horizontal side portion 4b which is the first side portion, in a state where one first side portion on the side where the bellows 3 abuts is arranged horizontally and the other second side portion is arranged in the vertical direction provided upright with respect to the first side portion. That is, the actuating plate 4 is formed in an L shape in which the vertical side portion 4a and the horizontal side portion 4b are bent starting from the bent portion 4c. The bellows 3 is arranged to abut against the lower portion of the horizontal side portion 4b of the actuating plate 4. Further, a spring 5 that opposes the movement of the actuating plate 4 and an actuating shaft 6 that operates in response to the movement of the actuating plate 4 are engaged with the vertical side portion 4a of the actuating plate 4. In FIG. 2, the spring 5 and the actuating shaft 6 are omitted for convenience.

[0016] In such a pressure switch 1, one end side of the actuating shaft 6 is engaged with the vertical side portion 4a of the actuating plate 4, and the other end side is engaged with the movable contact plate 11 that constitutes the microswitch 10. Further, the microswitch 10 includes, for example, two fixed contacts 12A, 12B and a movable contact 13 arranged therebetween. In the microswitch 10, the movable contact 13 with respect to the fixed contacts 12A, 12B is provided at the free end of the movable contact plate 11. The movable contact plate 11 has a rapid inversion mechanism including a deformation spring 14. The movable contact plate 11 receives the operation of the actuating plate 4 via the actuating shaft 6, and thereby makes the movable contact 13 contact and separate from the fixed contacts 12A, 12B.

[0017] And in such a pressure switch 1, when the pressure applied to the bellows 3 increases or decreases, and the actuating plate 4 rotates about the fulcrum 2a, the movable contact plate 11 operates via the actuating shaft 6 that operates in response to the movement of the actuating plate 4. As a result, the movable contact plate 11 selectively connects the movable contact 13 between one or two fixed contacts 12A, 12B, and the microswitch 10 is inverted.

[0018] Also, in the pressure switch 1, on the main body 2, a pressure increase side stopper 2b that restricts the rotational movement of the operating plate 4 and a pressure decrease side stopper 2c are provided at a predetermined interval in the vertical direction near the end of the lateral side portion 4b of the operating plate 4. When excessive pressure is applied to the bellows 3, the operating plate 4 is held by the fulcrum 2a provided on the main body 2 and the pressure increase side stopper 2b provided above the side portion inside the main body 2, thereby preventing the bellows 3 from extending.

[0019] Here, in a conventional pressure switch, when the pressure applied to the bellows becomes even higher, the bellows may extend while tilting, causing the operating plate of the main body to tilt. Then, the operating plate that has lost its support relationship with the main body tilts with the end of the lateral side portion facing downward, and is pushed up by the lower bellows As a result, the end of the lateral side portion may come off the pressure decrease side stopper and drop toward the bottom plate. In this case, the dropout of the operating plate not only causes damage to the bellows, but also there is a risk of leakage of a pressure medium such as a refrigerant.

[0020] Therefore, the pressure switch 1 of the present embodiment includes a shaft 7 provided coaxially with the fulcrum 2a near the operating plate 4 inside the main body 2, and a displacement prevention stopper 9 provided at a position on the end side of the lateral side portion 4b of the operating plate 4 with respect to the shaft 7. Then, as shown in FIG. 2, when excessive pressure is applied to the bellows 3 and the fulcrum 2a is destroyed, the displacement prevention stopper 9 abuts against the shaft 7.

[0021] Specifically, the shaft 7 is located on the side of the lateral side portion 4b of the operating plate 4 inside the main body 2 that is opposite to the bellows 3, on the other end side of the lateral side portion 4b sandwiching the contact position of the bellows 3 with respect to the fulcrum 2a, and on the side of the bent portion 4c of the operating plate 4 with respect to the displacement prevention stopper 9.

[0022] According to the above-described embodiment, even when an excessive pressure is applied to the bellows 3 and the operating plate 4 loses its support relationship with the main body 2 due to the destruction of the fulcrum 2a, the end portion of the lateral side portion 4b is pushed upward by the lower bellows 3 in a state of being inclined downward. Therefore, by the displacement prevention stopper 9 coming into contact with the shaft 7, it is possible to prevent the operating plate 4 from dropping in the direction of the bottom plate, suppress damage to the main body 2 and the bellows 3, and improve pressure resistance.

[0023] Further, the shaft 7 is located on the side of the operating plate 4 in the main body 2 opposite to the bellows 3, on the diagonal line with respect to the fulcrum 2a, and on the side of the bent portion 4c of the operating plate 4 rather than the displacement prevention stopper 9 above the lateral side portion 4b of the operating plate 4. Therefore, even when an excessive pressure is applied to the bellows 3 and the bellows 3 extends while tilting, causing the operating plate 4 of the main body 2 to tilt, the displacement prevention stopper 9 surely comes into contact with the shaft 7, ensuring the dropping of the operating plate 4 as described above and improving pressure resistance, thereby surely suppressing damage to the bellows 3 and preventing leakage of the pressure medium.

[0024] Although not shown here, the operating plate 4 may form a raised portion protruding toward the side where the shaft 7 of the lateral side portion 4b is arranged, and the raised portion may function as a displacement prevention stopper. In this case, by simply forming a raised portion protruding inward on the lateral side portion 4b of the operating plate 4, the displacement prevention stopper can be easily configured, and there is no need to provide the displacement prevention stopper as a separate member, which has the advantage of reducing parts.

[0025] Further, the pressure switch of the present invention is not limited to the above-described embodiment. That is, as shown in FIGS. 3 and 4 in which the same reference numerals are given to the corresponding portions as in FIGS. 1 and 2, a reset plate 20 may be further provided, which is arranged along the upper portion of the operating plate 4, has a bent portion 20a at the free end, and is fastened to the lateral side portion 4b of the operating plate 4 using a rivet 21. Note that the spring 5 in FIG. 3, the spring 5 in FIG. 4, and the operating shaft 6 are omitted for convenience.

[0026] In this case, the rivet 21 functions as a displacement prevention stopper by engaging with the shaft 7. Although not shown here, the operating plate 4 may have a raised portion that protrudes inwardly from the lateral side portion 4b, and the raised portion may be made to function as a displacement prevention stopper.

[0027] According to the above modification, the reset plate 20 fastened using the rivet 21 to the lateral side portion 4b of the operating plate 4 is further provided, and since the rivet 21 for fixing the reset plate 20 can be diverted as a displacement prevention stopper, in addition to the effects of the above-described embodiment, the labor and cost of providing a stopper can be saved.

[0028] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and design changes and the like within the scope not departing from the gist of the present invention are also included in the present invention.

Explanation of Reference Numerals

[0029] 1 Pressure switch 2 Body 2a Fulcrum 3 Bellows (pressure-responsive part) 4 Operating plate 4a Vertical side portion (second side portion) 4b Lateral side portion (first side portion) 4c Bent portion 4d Raised portion 5 Spring 6 Operating shaft 7 Shaft 9 Displacement prevention stopper 10 Microswitch 11 Movable contact plate 12A, 12B Fixed contacts 13 Movable contact 14 Deformation spring 20 Reset plate 21 Rivet 22 Screw

Claims

1. A pressure switch having a pressure responsive portion within a body, an actuating plate having an insertion hole through which a fulcrum provided on the body is rotatably inserted and which rotates about the fulcrum by expansion and contraction of the pressure responsive portion, a spring which opposes the movement of the actuating plate, an actuating shaft which responds to the movement of the actuating plate, and a movable contact plate which moves a movable contact with and away from a fixed contact by the movement of the actuating shaft, The actuation plate has a first side portion having a contact portion with which the pressure responsive portion contacts, and a second side portion continuing to one end side of the first side portion via a bent portion, A pressure switch, characterized in that, in a non-pressurized state of the pressure switch, the abutment portion is located within a range of an opening of the insertion hole in a direction in which the pressure responsive portion expands and contracts.

2. 2. The pressure switch according to claim 1, wherein the insertion hole is located inside an outer shape of an upper surface of the pressure responding portion.

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