Pull rod reset type small air-tight seal travel switch

Abstract

The utility model provides a pull rod reset type small air-tight seal travel switch, which comprises a shell, a base and an air-tight seal microswitch unit, the shell is installed on the upper end face of the base, and the air-tight seal microswitch unit is installed in the base. A push cylinder is arranged in the shell, and the upper end of the push cylinder is connected with a roller through a roller shaft; an ejector rod is arranged between the push cylinder and the base and is connected with the push cylinder through a pull rod; a first reset pressure spring is arranged between the ejector rod and the push cylinder, and a second reset pressure spring is arranged between the base and the push cylinder. In a travel switch range-extending mechanism, especially a plunger type range-extending mechanism, the composite application of the pull rod and the reset pressure spring can save the use of the reset pressure spring at the bottom of the push rod, so that the space in the height direction of the switch can be saved, and the purpose of reducing the size of the switch is achieved; the air-tight travel switch is suitable for the air-tight travel switch of which the size of the switch body is strictly controlled.

Description

Technical Field

[0001] The utility model relates to a pull-rod reset type small airtight seal travel switch, belonging to the technical field of mechanical switches. Background Art

[0002] Hermetic micro switches have good environmental adaptability and explosion-proof properties, so they are widely used in aerospace (low temperature, high temperature, vacuum, radiation, etc.) and special environments in aviation (engine compartment high temperature, oil and gas, etc.).

[0003] Due to the special requirements of airtightness, the hermetic micro switch usually adopts bellows or metal diaphragm to achieve dynamic sealing. Since the effective deformation of the metal diaphragm is small, the switch does not have a large stroke characteristic. Therefore, in order to increase the stroke characteristic or operating force of the hermetic switch, it is usually necessary to add a range-extending mechanism outside the hermetic switch unit. Common range-extending mechanisms include spring-type, lever-type, plunger-type, etc. Among them, the plunger-type range-extending mechanism can well control the stroke parameters of the switch because of the use of compression spring reset. This type of range-extending mechanism also has the advantages of high life and vibration resistance. However, since the plunger-type range-extending mechanism adopts compression spring reset, the internal space needs to consider the height of the compression spring and other issues, resulting in the large height dimension of this type of range-extending mechanism, and its height dimension is usually more than 20mm.

[0004] Therefore, when the use environment has high requirements on the height size of the switch, this type of range extension mechanism cannot be applied. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a pull rod reset type small airtight seal travel switch, which utilizes the combined application of a pull rod and a compression spring to reduce the use of a push rod reset compression spring and save switch height space.

[0006] The utility model is realized through the following technical solutions.

[0007] The utility model provides a pull rod reset type small air-sealed travel switch, comprising a shell, a base and an air-sealed micro switch unit; the shell is installed on the upper end surface of the base, and the air-sealed micro switch unit is installed in the base; a push cylinder is provided in the shell, and the upper end of the push cylinder is connected to a roller through a roller shaft; a push rod is provided between the push cylinder and the base, and the push rod is connected to the push cylinder through a pull rod; a reset compression spring A is provided between the push rod and the push cylinder, and a reset compression spring B is provided between the base and the push cylinder.

[0008] The upper end surface of the shell is provided with a waist-shaped through hole with a flat position, and the push tube is installed in the waist-shaped through hole and slides along the waist-shaped through hole.

[0009] The two sides of the push cylinder are milled with flat surfaces, which cooperate with the waist-shaped through hole to stop rotation.

[0010] A sealing ring is arranged between the airtight micro switch unit and the base, and the sealing ring and the airtight micro switch unit are pressed tightly in the base through a compression screw sleeve.

[0011] A tail ring is provided at the bottom of the base.

[0012] The lower end of the pull rod is welded and fixed to the push rod, and the upper end of the pull rod slides along the height direction of the push cylinder.

[0013] The beneficial effect of the utility model is that in the travel switch range extending mechanism, especially the plunger type range extending mechanism, the combined application of the pull rod and the return compression spring can save the use of the return compression spring at the bottom of the push rod, thereby saving space in the height direction of the switch, achieving the purpose of reducing the size of the switch, and is suitable for airtight travel switches with strict control over the size of the switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model;

[0015] Figure 2 It is a structural schematic diagram of the utility model from another angle;

[0016] In the figure: 1-housing, 2-push cylinder, 3-roller, 4-roller shaft, 5-reset spring A, 6-reset spring B, 7-pull rod, 8-thrust rod, 9-base, 10-sealing ring, 11-compression screw sleeve, 12-tail ring, 13-air-sealed micro switch unit. DETAILED DESCRIPTION

[0017] The technical solution of the utility model is further described below, but the scope of protection required is not limited to the description.

[0018] like Figure 1 and 2 As shown, the upper end face of the shell 1 is processed with a waist-shaped through hole with a flat position, and the shell 1 is equipped with a push cylinder 2 that can slide along the waist-shaped through hole of the shell. Flat surfaces are milled on both sides of the push cylinder 2 to cooperate with the waist-shaped through hole of the shell to stop rotation; the upper end of the push cylinder 2 is equipped with a roller 3 by welding a roller shaft 4, and the lower end face of the push cylinder 2 is equipped with a reset spring A 5 and a reset spring B 6; the upper end face of the reset spring A 5 contacts the push cylinder 2, and the lower end face contacts the push rod 8, and the push rod 8 is connected to the push cylinder 2 through two pull rods 7; the upper end face of the reset spring B 6 contacts the push cylinder 2, and the lower end face contacts the base 9, and a tail ring 12 is welded to the bottom of the base 9; a micro switch unit 13 with an air-sealing function is installed in the base 9, and a sealing gasket 10 is installed between the mating surfaces of the air-sealed micro switch unit 13 and the base 9; the sealing gasket 10 and the air-sealed switch unit 13 are pressed in the base 9 by a compression screw sleeve 11 to ensure the electrical reliability of the switch in a water vapor environment.

[0019] Specifically, the lower end surface of the pull rod 7 is fixed to the push rod 8 by welding, and the upper end can slide along the height direction of the push tube 2; the pull rod 7 and the reset compression spring B 6 can realize the reset function of the push rod 8.

[0020] The working process of the utility model is:

[0021] When the switch roller 3 is driven by an external force, the push cylinder 2 moves downward to compress the reset spring A5 and the reset spring B7. Under the action of the reset spring A5, the push rod 8 is pushed downward to trigger the internal airtight micro switch unit 13. During the downward movement of the push rod 8, the pull rod 7 is driven downward. When the limit surface of the push rod 8 is in rigid contact with the limit surface of the base 9, the push rod 8 stops moving. At this time, if the driving force is continued to be applied to use the switch overtravel, the position of the push cylinder 2 continues to decrease, and the upper end of the pull rod 7 slides upward relative to the position of the push cylinder 2. When the external driving force is withdrawn, the push cylinder 2 is reset upward under the action of the reset spring B6. When the push cylinder 2 reaches the contact position with the pull rod 7, it drives the pull rod 7 to reset upward together. The pull rod 7 drives the push cylinder 8 to reset upward, and the internal airtight micro switch unit 13 is released.

Claims

1. A pull rod reset type small airtight travel switch, comprising a housing (1), a base (9) and an airtight micro switch unit (13), characterized in that: The housing (1) is mounted on the upper end surface of the base (9), and the airtight micro switch unit (13) is mounted inside the base (9); a push cylinder (2) is arranged inside the housing (1), and the upper end of the push cylinder (2) is connected to a roller (3) via a roller shaft (4); a push rod (8) is arranged between the push cylinder (2) and the base (9), and the push rod (8) is connected to the push cylinder (2) via a pull rod (7); a return spring A (5) is arranged between the push rod (8) and the push cylinder (2), and a return spring B (6) is arranged between the base (9) and the push cylinder (2).

2. The pull-rod reset type small airtight travel switch according to claim 1, characterized in that: The upper end surface of the shell (1) is provided with a waist-shaped through hole with a flat position, and the push cylinder (2) is installed in the waist-shaped through hole and slides along the waist-shaped through hole.

3. The pull-rod reset small airtight travel switch according to claim 2, characterized in that: The two sides of the push cylinder (2) are milled with flat surfaces, which cooperate with the waist-shaped through hole to stop rotation.

4. The pull-rod reset type small airtight travel switch according to claim 1, characterized in that: A sealing ring (10) is provided between the airtight micro switch unit (13) and the base (9), and the sealing ring (10) and the airtight micro switch unit (13) are pressed tightly into the base (9) via a compression screw sleeve (11).

5. The pull-rod reset type small airtight travel switch according to claim 1, characterized in that: A tail ring (12) is provided at the bottom of the base (9).

6. The pull-rod reset type small airtight travel switch according to claim 1, characterized in that: The lower end of the pull rod (7) is welded and fixed to the push rod (8), and the upper end of the pull rod (7) slides along the height direction of the push cylinder (2).

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