Lifting type switch

Abstract

The utility model relates to a lifting type switch, and belongs to the technical field of electrical switches. When the pull shaft is inserted, the bottom end of the pull shaft can drive the limiting piece to retract into the radial sliding hole until the limiting piece reaches the position, right opposite to the limiting piece, of the limiting clamping groove, the limiting piece moves centripetally under the action of spring force of the compression spring A, the limiting clamping part is clamped with the limiting clamping groove in the outer wall of the pull shaft, and then the pull shaft is in a locked state; maintaining a circuit on the printed circuit board to be in a disconnected state; when the pull shaft is pulled out upwards, the side wall of the lower end of the limiting clamping groove extrudes the limiting clamping part of the limiting piece, after the spring force of the compression spring A is overcome, the limiting piece retracts into the radial sliding hole, the pull shaft can be pulled out smoothly, under the action of the reset spring force of the compression spring B, the core shaft moves upwards to be reset, and the circuit is continuously in an on state. According to the utility model, the opening and closing of the switch can be correspondingly realized only by inserting and pulling out the pull shaft, the rotation action is omitted, and the operation is more convenient.

Description

Technical Field

[0001] The utility model relates to a pull-type switch, belonging to the technical field of electrical switches. Background Art

[0002] The existing pull-type switch mainly includes a pull shaft and a switch body. The switch body includes a shell, a pull shaft fixing component and a contact opening and closing component. The inside of the shell is a shell mounting cavity with a hollow structure. The pull shaft fixing component and the contact opening and closing component are both arranged in the shell mounting cavity. The contact opening and closing component usually includes a moving contact, a static contact and a mandrel for controlling the engagement and disconnection of the moving contact and the static contact. The pull shaft is used to drive and control the movement of the mandrel. The pull shaft fixing component is used to lock the pull shaft, so that the circuit corresponding to the switch body is maintained in an on state or an off state. The existing pull shaft and the pull shaft fixing component usually adopt a rotating engagement method, by inserting the positioning end at the bottom of the pull shaft into the corresponding matching hole of the switch shell and then rotating 90° to fix it with the positioning groove in the switch shell; when the pull shaft needs to be pulled out, the operation process is reversed, and it is necessary to rotate 90° in the opposite direction before pulling out the pull shaft. This structure has some disadvantages: the pull shaft plugging and unplugging method is too cumbersome, and the switch cannot be quickly turned on and off at a critical moment. In addition, there is usually no sealing structure between the pull shaft and the switch body, which cannot be effectively waterproof. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a pull-type switch which has more convenient plugging and unplugging operations.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: a pull-type switch, including a pull shaft and a switch body, the switch body includes a shell, a pull shaft fixing component and a contact opening and closing component, the inside of the shell is a shell installation cavity with a hollow structure, the pull shaft fixing component and the contact opening and closing component are both arranged in the shell installation cavity, the contact opening and closing component includes a gasket, a core shaft, a printed circuit board, a probe, a conductive sheet, a compression spring B and a base, with the axis of the core shaft being arranged vertically as a reference state, the gasket, the printed circuit board and the base are fixedly arranged in the shell installation cavity from top to bottom in sequence, and the gasket and the printed circuit board are both provided with a contact with the core shaft The center hole is adapted to fit the core shaft, and the center hole of the liner forms a sliding fit. The conductive sheet is fixedly arranged at the lower end of the core shaft. The upper surface of the base has a base groove that can accommodate the conductive sheet and the lower end of the core shaft to move up and down. The compression spring B is arranged between the lower end of the core shaft and the bottom wall of the base groove. The probes are fixedly arranged on the printed circuit board in pairs. When the compression spring B is in a natural state, the conductive sheet contacts the probes so that the circuit on the printed circuit board is in a connected state; the pull shaft fixing assembly includes an inner sleeve, a limiter and a compression spring A. The inner sleeve is fixedly arranged at the upper position of the liner. The inner sleeve has a vertically arranged inner sleeve center hole. The side of the inner sleeve center hole The wall is provided with one or more radial sliding holes distributed in annular intervals, the inner ends of the radial sliding holes are connected with the center hole of the inner sleeve, and a set of limit pieces and compression springs A are correspondingly arranged in each radial sliding hole. The end of the limit piece close to the center hole of the inner sleeve has a limit clamping portion, and the compression spring A is arranged at the end of the limit piece away from the center hole of the inner sleeve. The limit piece can reciprocate along the radial sliding hole. When the compression spring A is in a natural state, the limit clamping portion of the limit piece extends outward into the center hole of the inner sleeve; the pull shaft can be inserted into the center hole of the inner sleeve from top to bottom and form a sliding fit with the center hole of the inner sleeve, and the lower end of the pull shaft can drive the core shaft to move downward. So that the conductive sheet is separated from the probe, and the circuit on the printed circuit board is in a disconnected state; the middle part of the outer wall of the pull shaft is provided with a limit slot matched with the limit engaging portion of the limit piece, the bottom end of the outer wall of the pull shaft is provided with a first driving surface for driving the limit piece to retract into the radial sliding hole, and the outer end of the lower side wall of the limit slot is provided with a second driving surface for driving the limit piece to retract into the radial sliding hole; when the pull shaft is inserted into the center hole of the inner sleeve, and the limit engaging portion of the limit piece is engaged with the limit slot on the outer wall of the pull shaft, the lower end of the pull shaft abuts against the upper end of the core shaft, and the circuit on the printed circuit board is in a disconnected state.

[0005] A further preferred solution is that when the limiting engaging portion of the limiting member is engaged with the limiting engaging groove of the outer wall of the pull shaft, the lower end of the pull shaft is simultaneously in contact with the upper end of the pad.

[0006] A further preferred solution is that the limiting engaging portion of the limiting member is a spherical surface, and the inner wall of the radial sliding hole is provided with an annular limiting flange at one end close to the center hole of the inner sleeve, and the annular limiting flange makes the portion of the limiting engaging portion extending outward into the center hole of the inner sleeve less than half of a hemisphere.

[0007] A further preferred solution is that the limiting member is a spherical member, and the limiting grooves are continuously arranged in a ring shape.

[0008] A further preferred solution is that the outer end of the radial sliding hole is connected to the outer surface of the inner sleeve, and the end of the compression spring A away from the limiting member abuts against the inner wall of the housing installation cavity.

[0009] A further preferred solution is that a terminal is fixedly arranged on the printed circuit board, the terminal is arranged vertically, and the lower end of the terminal passes through the through hole on the base and extends to the outside of the shell.

[0010] A further preferred solution is: the top of the outer shell mounting cavity is an annular top plate of the outer shell, the lower surface of the annular top plate of the outer shell contacts the upper end surface of the inner sleeve, and a sealing ring A is arranged between the contact surfaces of the two, the annular top plate of the outer shell has a top plate center hole for the pull shaft to pass through, and the sealing ring A is arranged around the top plate center hole; the inner circumferential surface of the sealing ring A is located on the mating surface with the outer wall of the pull shaft.

[0011] A further preferred solution is: a sealing ring C is arranged between the outer circumferential surface of the gasket and the inner circumferential surface of the housing mounting cavity; a sealing ring B is arranged between the inner wall of the center hole of the gasket and the outer circumferential surface of the core shaft, the lower end of the center hole of the gasket is arranged as a step hole, the sealing ring B is arranged in the step hole, and a bushing coaxial with the core shaft is fixed in the step hole, and the upper end surface of the bushing serves as a limit for the sealing ring B.

[0012] A further preferred solution is that a pull ring is connected to the upper end of the pull shaft.

[0013] A further preferred solution is: a mounting assembly is arranged on the outer circumferential surface of the shell; the mounting assembly includes a mounting plate, a washer and a nut, a mounting hole is opened on the mounting plate, the shell is installed in the mounting hole of the mounting plate, the upper end of the shell has a limiting protrusion in contact with the upper surface of the mounting plate, the nut and the outer circumferential surface of the shell form a threaded connection, the washer is arranged between the upper end surface of the nut and the lower surface of the mounting plate, the washer is arranged around the shell, and the mounting plate is locked and fixed between the limiting protrusion of the shell and the washer by the nut.

[0014] The beneficial effects of the utility model are as follows: the opening and closing actions of the utility model are simple and quick. When inserting the pull shaft, the bottom end of the pull shaft can drive the limiter to retract into the radial sliding hole until the limiter slot is directly opposite to the limiter. The limiter moves centripetally under the spring force of the compression spring A, so that the limiter engages with the limiter slot on the outer wall of the pull shaft, thereby making the pull shaft in a locked state and maintaining the circuit on the printed circuit board in a disconnected state; when the pull shaft is pulled upward, the lower end side wall of the limiter slot squeezes the limiter engages, and after overcoming the spring force of the compression spring A, the limiter retracts into the radial sliding hole, and the pull shaft can be pulled out smoothly. Under the reset spring force of the compression spring B, the core shaft moves upward and resets, and the conductive sheet contacts the probe to keep the circuit on the printed circuit board in a connected state. The utility model only needs to insert and pull out the pull shaft to realize the disconnection and closing of the switch, eliminating the rotation action and making the operation more convenient. In addition, the utility model uses the probe on the printed circuit board as a static contact, which can meet the soft connection opening and closing and increase the service life of the switch. The utility model has a sealing waterproof structure between the pull shaft and the switch body, the switch interior and the shell, and the core shaft and the switch interior, which can meet the waterproof requirements of the switch in different states of opening and closing. In summary, the utility model has the advantages of reliable operation, simple operation, vibration resistance, waterproofness, and good reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a half-section schematic diagram of the overall structure of the utility model.

[0016] Figure 2 for Figure 1 A partial enlargement of the area where the middle pad is located.

[0017] Markings in the figure: pull ring 1, pull shaft 2, outer shell 3, sealing ring A4, inner sleeve 5, limit piece 6, compression spring A7, sealing ring B8, gasket 9, sealing ring C10, core shaft 11, bushing 12, printed circuit board 13, probe 14, conductive sheet 15, compression spring B16, base 17, mounting plate 18, washer 19, nut 20, terminal 21. DETAILED DESCRIPTION

[0018] The utility model will be further described below in conjunction with the accompanying drawings.

[0019] like Figure 1 and Figure 2As shown, the utility model includes a pull shaft 2 and a switch body, the switch body includes a shell 3, a pull shaft fixing assembly and a contact opening and closing assembly, the interior of the shell 3 is a shell mounting cavity with a hollow structure, the pull shaft fixing assembly and the contact opening and closing assembly are both arranged in the shell mounting cavity, the contact opening and closing assembly includes a gasket 9, a core shaft 11, a printed circuit board 13, a probe 14, a conductive sheet 15, a compression spring B16 and a base 17, with the axis of the core shaft 11 being arranged vertically as a reference state, the gasket 9, the printed circuit board 13 and the base 17 are fixedly arranged in the shell mounting cavity from top to bottom in sequence, the gasket 9 and the printed circuit board 13 are both provided with a center hole adapted to the core shaft 11, and the core shaft 11 and The center hole of the gasket 9 forms a sliding fit, the conductive sheet 15 is fixedly arranged at the lower end of the core shaft 11, and the upper surface of the base 17 has a base groove that can accommodate the conductive sheet 15 and the lower end of the core shaft 11 to move up and down. The compression spring B16 is arranged between the lower end of the core shaft 11 and the bottom wall of the base groove. The probes 14 are fixedly arranged in pairs on the printed circuit board 13. When the compression spring B16 is in a natural state, the conductive sheet 15 contacts the probes 14 so that the circuit on the printed circuit board 13 is in a connected state; the pull shaft fixing assembly includes an inner sleeve 5, a limit member 6 and a compression spring A7. The inner sleeve 5 is fixedly arranged at the upper position of the gasket 9. The inner sleeve 5 has a vertically arranged inner sleeve center hole. The side wall of the center hole is provided with one or more radial sliding holes distributed in an annular manner, the inner end of the radial sliding hole is connected to the center hole of the inner sleeve, and a set of limit members 6 and compression springs A7 are correspondingly arranged in each radial sliding hole. The end of the limit member 6 close to the center hole of the inner sleeve has a limit clamping portion, and the compression spring A7 is arranged at the end of the limit member 6 away from the center hole of the inner sleeve. The limit member 6 can reciprocate along the radial sliding hole. When the compression spring A7 is in a natural state, the limit clamping portion of the limit member 6 extends outward into the center hole of the inner sleeve; the pull shaft 2 can be inserted into the center hole of the inner sleeve from top to bottom and form a sliding fit with the center hole of the inner sleeve, and the lower end of the pull shaft 2 can drive the core shaft 11 to move downward to The conductive sheet 15 is disengaged from the probe 14, thereby placing the circuit on the printed circuit board 13 in a disconnected state; the middle portion of the outer wall of the pull shaft 2 has a limit slot matched with the limit engaging portion of the limit member 6, the bottom end of the outer wall of the pull shaft 2 has a first driving surface for driving the limit member 6 to retract into the radial sliding hole, and the outer end of the lower side wall of the limit slot has a second driving surface for driving the limit member 6 to retract into the radial sliding hole; when the pull shaft 2 is inserted into the center hole of the inner sleeve, and the limit engaging portion of the limit member 6 is engaged with the limit slot on the outer wall of the pull shaft 2, the lower end of the pull shaft 2 abuts against the upper end of the core shaft 11, and the circuit on the printed circuit board 13 is in a disconnected state.

[0020] When the pull shaft 2 is inserted downward, the bottom end of the pull shaft 2 can drive the limiter 6 to retract into the radial sliding hole, and the lower end surface of the pull shaft 2 will first contact the core shaft 11 and drive the core shaft 11 to move downward, so that the conductive sheet 15 is separated from the probe 14, and then the circuit on the printed circuit board 13 is disconnected; the pull shaft 2 and the core shaft 11 move downward as a whole until the pull shaft 2 reaches the position where the limiter slot is opposite to the limiter 6, and the limiter 6 generates a centripetal movement under the spring force of the compression spring A7, so that its limiter engaging portion is in contact with the outer surface of the pull shaft 2. The limit slots of the wall are engaged with each other, so that the pull shaft 2 is in a locked state, maintaining the circuit on the printed circuit board 13 in a disconnected state; when the pull shaft 2 is pulled out upward, the lower end side wall of the limit slot squeezes the limit engaging portion of the limit member 6, and after overcoming the spring force of the compression spring A7, the limit member 6 is retracted into the radial sliding hole, and the pull shaft 2 can be smoothly pulled out upward. Under the action of the reset spring force of the compression spring B16, the core shaft 11 moves upward and resets, and the conductive sheet 15 contacts the probe 14 so that the circuit on the printed circuit board 13 is continuously in the connected state. It can be understood that the pull shaft 2 only needs to be able to meet the vertical displacement requirements of the switch opening and closing. When the pull shaft 2 is pulled out upward, it is only necessary to ensure that the core shaft 11 moves upward and resets, and the conductive sheet 15 contacts the probe 14. The pull shaft 2 can be retained in the switch body, or the switch body can be completely pulled out.

[0021] To further facilitate the operation and ensure that the limiting engaging portion of the limiting member 6 can be smoothly engaged with the limiting slot on the outer wall of the pull shaft 2, it is usually considered to add a vertical displacement stroke limiting mechanism to the pull shaft 2. To make the structure simple and reliable, the preferred solution is that when the limiting engaging portion of the limiting member 6 is engaged with the limiting slot on the outer wall of the pull shaft 2, the lower end of the pull shaft 2 is simultaneously in contact with the upper end of the liner 9, which is equivalent to the upper end surface of the liner 9 being the lower limit position of the movement of the pull shaft 2. In some alternative embodiments, it is also considered to add a vertical slide groove to the center hole of the inner sleeve, and to add a corresponding guide protrusion to the side wall of the pull shaft 2. The guide protrusion can slide in the vertical slide groove, and the bottom end position of the vertical slide groove is used as the lower limit position of the movement of the pull shaft 2.

[0022] Specifically, the first driving surface involved in the downward insertion of the pull shaft 2, the outer wall bottom end of the pull shaft 2 driving the limiter 6 to retract into the radial sliding hole, and the second driving surface involved in the upward pulling of the pull shaft 2, the lower side wall outer end of the limiter slot driving the limiter 6 to retract into the radial sliding hole, can be implemented in a variety of ways, and any transmission mechanism that can convert vertical displacement into lateral displacement in the prior art can be adopted, such as conventional inclined planes and inclined planes, inclined planes and curved planes, curved planes and curved planes, etc. That is, in order to meet the above-mentioned motion principle, the first driving surface and the second driving surface can usually be inclined plane structures or curved surface structures; the limiting engaging part of the limiter 6 only needs the outer end upper surface and the outer end lower surface to have inclined plane structures or curved surface structures respectively, and in some special embodiments, the first driving surface and the second driving surface can also be planes, for example, the limiter 6 is in the form of a steel ball, and the outer convex transmission part of the steel ball only needs to be less than half of a hemisphere, and the up and down movement of the horizontal driving surface can also squeeze the steel ball to move horizontally. In order to make the structure simple and reliable, the limiting engaging part of the limiting member 6 is designed as a spherical surface. In order to prevent the limiting member 6 from slipping out of the inner sleeve center hole and ensure that the limiting member 6 can be squeezed and retracted into the radial sliding hole when the pull shaft 2 moves vertically to the corresponding position, the preferred solution is that the inner wall of the radial sliding hole is provided with an annular limiting flange at one end close to the inner sleeve center hole, and the annular limiting flange makes the portion of the limiting engaging part extending outward into the inner sleeve center hole less than half of the hemispherical surface. It can be understood that in some alternative embodiments, the two ends of the compression spring A7 can also be fixedly arranged to prevent the limiting member 6 from slipping out of the inner sleeve center hole. Here, "the limiting engaging part of the limiting member 6 is designed as a spherical surface" can be understood in a broad sense, for example, the limiting member 6 can be designed as a cylindrical member with a hemispherical surface at one end, or the limiting member 6 can be directly designed as a spherical member as a whole. The preferred solution is to design it as a spherical member as a whole, which can usually be in the form of a steel ball.

[0023] In addition, the limit slots can be in a one-to-one correspondence with the limit member 6, or can be arranged in a continuous annular shape. The preferred solution is that the limit slots are arranged in a continuous annular shape, which can simplify the device structure and improve the convenience of inserting the pull shaft 2. The main body of the pull shaft 2 can generally adopt a cylindrical structure. No matter from which angle the pull shaft 2 is inserted downward, it can be ensured that the limit slots can form a snap fit with the limit member 6. When the limit slots are in a one-to-one correspondence with the limit member 6, the pull shaft 2 needs to be inserted downward along a specific angle. At this time, the cross-section of the pull shaft 2 can be designed to be a rectangle. Of course, it can also be achieved by adding a vertical guide structure to the mating surface of the pull shaft 2 and the center hole of the inner sleeve. For example, the vertical slide groove is added to the center hole of the inner sleeve as mentioned above, and a guide protrusion is added to the side wall of the pull shaft 2. The guide protrusion can slide in the vertical slide groove.

[0024] On the basis of the above preferred solution, in order to facilitate processing and assembly, it is preferred that the outer end of the radial sliding hole is connected to the outer surface of the inner sleeve 5, and the end of the compression spring A7 away from the stopper 6 is in contact with the inner wall of the housing installation cavity. In this solution, the two ends of the compression spring A7 can be freely arranged without the need for an additional fixing structure, and one end of the compression spring A7 is in contact with the stopper 6 and the other end is in contact with the inner wall of the housing installation cavity.

[0025] A terminal 21 for connecting wires is fixedly provided on the printed circuit board 13. The terminal 21 can be designed at a suitable position of the switch body. To facilitate assembly and wiring, the preferred arrangement is that the terminal 21 is vertically arranged, and the lower end of the terminal 21 passes through the through hole on the base 17 and extends to the outside of the housing 3.

[0026] In order to improve the waterproof performance, the utility model is designed with a series of sealing structures, specifically as follows: the top of the housing installation cavity is a housing annular top plate, the lower surface of the housing annular top plate contacts the upper end surface of the inner sleeve 5, and a sealing ring A4 is arranged between the contact surfaces of the two, the housing annular top plate has a top plate center hole for the pull shaft 2 to pass through, and the sealing ring A4 is arranged around the top plate center hole; the inner circumference of the sealing ring A4 is preferably arranged on the matching surface with the outer wall of the pull shaft 2. A sealing ring C10 is arranged between the outer circumference of the gasket 9 and the inner circumference of the housing installation cavity; a sealing ring B8 is arranged between the inner wall of the center hole of the gasket 9 and the outer circumference of the core shaft 11. In order to facilitate assembly and ensure the reliability of the guiding performance of the core shaft 11, the lower end of the center hole of the gasket 9 is arranged as a step hole, and the sealing ring B8 is arranged in the step hole. A bushing 12 coaxial with the core shaft 11 is fixedly arranged in the step hole, and the upper end of the bushing 12 plays a limiting role for the sealing ring B8.

[0027] In order to facilitate pulling out the pull shaft 2, a pull ring 1 is connected to the upper end of the pull shaft 2. The pull ring 1 can usually be connected to the connecting through hole at the upper end of the pull shaft 2.

[0028] To facilitate installation, a mounting assembly is provided on the outer circumference of the housing 3; the mounting assembly includes a mounting plate 18, a washer 19 and a nut 20. The mounting plate 18 is provided with a mounting hole, the housing 3 is mounted in the mounting hole of the mounting plate 18, the upper end of the housing 3 has a limiting protrusion in contact with the upper surface of the mounting plate 18, the nut 20 is threadedly connected with the outer circumference of the housing 3 (that is, the outer circumference of the housing 3 has a corresponding external thread structure), the washer 19 is provided between the upper end surface of the nut 20 and the lower surface of the mounting plate 18, the washer 19 is provided around the housing 3, and the mounting plate 18 is locked and fixed between the limiting protrusion of the housing 3 and the washer 19 through the nut 20. The limiting protrusion is usually designed to be arranged continuously in an annular shape.

Claims

1. A pull-type switch, comprising a pull shaft (2) and a switch body, wherein the switch body comprises a housing (3), a pull shaft fixing assembly and a contact opening and closing assembly, wherein the interior of the housing (3) is a housing mounting cavity of a hollow structure, wherein the pull shaft fixing assembly and the contact opening and closing assembly are both arranged in the housing mounting cavity, and wherein: The contact opening and closing assembly comprises a gasket (9), a core shaft (11), a printed circuit board (13), a probe (14), a conductive sheet (15), a compression spring B (16) and a base (17). The axis of the core shaft (11) is arranged vertically as a reference state. The gasket (9), the printed circuit board (13) and the base (17) are fixedly arranged in the housing installation cavity from top to bottom. The gasket (9) and the printed circuit board (13) are both provided with a center hole adapted to the core shaft (11). The core shaft (11) and the center hole of the gasket (9) form a sliding fit. The conductive sheet (15) is fixedly arranged at the lower end of the core shaft (11). The upper surface of the base (17) has a structure capable of accommodating the conductive sheet (15) and the core shaft. (11) The base groove at the lower end of the core shaft (11) moves up and down, the compression spring B (16) is arranged between the lower end of the core shaft (11) and the bottom wall of the base groove, and the probes (14) are fixedly arranged on the printed circuit board (13) in pairs. When the compression spring B (16) is in a natural state, the conductive sheet (15) contacts the probes (14) so ​​that the circuit on the printed circuit board (13) is in a connected state; the pull shaft fixing assembly includes an inner sleeve (5), a limit member (6) and a compression spring A (7), the inner sleeve (5) is fixedly arranged at a position above the gasket (9), the inner sleeve (5) has an inner sleeve center hole arranged vertically, and the side wall of the inner sleeve center hole is provided with one or more radial sliding holes distributed in an annular manner, and the radial sliding holes are arranged in a circular manner. The inner end of the movable hole is connected to the center hole of the inner sleeve, and a group of limit pieces (6) and compression springs A (7) are correspondingly arranged in each radial sliding hole. The end of the limit piece (6) close to the center hole of the inner sleeve has a limit clamping portion, and the compression spring A (7) is arranged at the end of the limit piece (6) away from the center hole of the inner sleeve. The limit piece (6) can move back and forth along the radial sliding hole. When the compression spring A (7) is in a natural state, the limit clamping portion of the limit piece (6) extends outward into the center hole of the inner sleeve; the pull shaft (2) can be inserted into the center hole of the inner sleeve from top to bottom and form a sliding fit with the center hole of the inner sleeve, and the lower end of the pull shaft (2) can drive the core shaft (11) to move downward, so that the conductive sheet (15) is separated from the probe (14). , thereby placing the circuit on the printed circuit board (13) in a disconnected state; the middle portion of the outer wall of the pull shaft (2) has a limit slot matched with the limit engaging portion of the limit member (6); the bottom end of the outer wall of the pull shaft (2) has a first driving surface for driving the limit member (6) to retract into the radial sliding hole; the outer end of the lower side wall of the limit slot has a second driving surface for driving the limit member (6) to retract into the radial sliding hole; when the pull shaft (2) is inserted into the central hole of the inner sleeve, and the limit engaging portion of the limit member (6) is engaged with the limit slot on the outer wall of the pull shaft (2), the lower end of the pull shaft (2) abuts against the upper end of the core shaft (11), and the circuit on the printed circuit board (13) is in a disconnected state.

2. The pull switch according to claim 1, characterized in that: When the limiting engaging portion of the limiting member (6) is engaged with the limiting engaging groove on the outer wall of the pull shaft (2), the lower end of the pull shaft (2) is simultaneously in contact with the upper end of the liner (9).

3. The pull switch according to claim 1, characterized in that: The limiting engaging portion of the limiting member (6) is a spherical surface, and the inner wall of the radial sliding hole is provided with an annular limiting flange at one end close to the center hole of the inner sleeve. The annular limiting flange makes the portion of the limiting engaging portion extending outward into the center hole of the inner sleeve less than half of a hemisphere.

4. The pull switch according to claim 3, characterized in that: The limiting member (6) is a spherical member, and the limiting grooves are continuously arranged in a ring shape.

5. The pull switch according to claim 3, characterized in that: The outer end of the radial sliding hole is connected to the outer surface of the inner sleeve (5), and the end of the compression spring A (7) away from the limiting member (6) is in contact with the inner wall of the housing installation cavity.

6. The pull switch according to claim 1, characterized in that: A terminal (21) is fixedly arranged on the printed circuit board (13). The terminal (21) is arranged vertically. The lower end of the terminal (21) passes through a through hole on the base (17) and extends to the outside of the housing (3).

7. The pull switch according to claim 1, characterized in that: The top of the housing installation cavity is a housing annular top plate, the lower surface of the housing annular top plate contacts the upper end surface of the inner sleeve (5), and a sealing ring A (4) is arranged between the contact surfaces of the two. The housing annular top plate has a top plate center hole for the pull shaft (2) to pass through, and the sealing ring A (4) is arranged around the top plate center hole; the inner circumferential surface of the sealing ring A (4) is located on the matching surface with the outer wall of the pull shaft (2).

8. The pull switch according to claim 1, characterized in that: A sealing ring C (10) is arranged between the outer circumference of the gasket (9) and the inner circumference of the housing mounting cavity; a sealing ring B (8) is arranged between the inner wall of the center hole of the gasket (9) and the outer circumference of the core shaft (11); the lower end of the center hole of the gasket (9) is arranged as a step hole, the sealing ring B (8) is arranged in the step hole, and a bushing (12) coaxial with the core shaft (11) is fixed in the step hole, and the upper end surface of the bushing (12) plays a limiting role for the sealing ring B (8).

9. The pull switch according to any one of claims 1 to 8, characterized in that: The upper end of the pull shaft (2) is connected with a pull ring (1).

10. The pull switch according to any one of claims 1 to 8, characterized in that: A mounting assembly is arranged on the outer peripheral surface of the housing (3); the mounting assembly comprises a mounting plate (18), a washer (19) and a nut (20); a mounting hole is arranged on the mounting plate (18); the housing (3) is mounted in the mounting hole of the mounting plate (18); the upper end of the housing (3) has a limiting protrusion in contact with the upper surface of the mounting plate (18); the nut (20) is threadedly connected to the outer peripheral surface of the housing (3); the washer (19) is arranged between the upper end surface of the nut (20) and the lower surface of the mounting plate (18); the washer (19) is arranged around the housing (3); and the mounting plate (18) is locked and fixed between the limiting protrusion of the housing (3) and the washer (19) through the nut (20).

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