Limiting sensor device and greenhouse cotton quilt spreading system

Abstract

The application relates to a limiting sensor device and a greenhouse cotton quilt spreading system. The limiting sensor device comprises a shell, a circuit board and a mercury switch. The shell is a hollow cuboid. The circuit board is arranged in the interior of the shell and located at the bottom of the shell. The mercury switch is arranged in the shell. The mercury switch is a hollow columnar structure. The mercury switch is arranged longitudinally on the circuit board. The interior of the mercury switch is provided with a mercury bead. The mercury bead can flow along the column length direction of the mercury switch. The bottom end of the mercury switch is electrically connected with the circuit board through a wire. The top end of the mercury switch extends upwards. The number of the mercury switches is two or more. Any two adjacent mercury switches are connected in series. The plurality of mercury switches are suitable for transmitting electric signals to the outside. The limiting sensor device has high sensitivity. The plurality of mercury switches can realize on-off control of the switches under a slight angle inclination. Therefore, the current rolling and spreading state of the greenhouse cotton quilt can be obtained more timely.

Description

Technical Field

[0001] This application relates to the field of greenhouse cotton quilt control technology, and in particular to a limit sensor device and a greenhouse cotton quilt spreading system. Background Technology

[0002] As consumers increasingly demand food safety and quality, the demand for organic and green food continues to grow, further driving the development of greenhouse agriculture and consequently boosting the market demand for greenhouse quilts. Currently, using limit switches as a stopping mechanism is a common practice in quilt spreading systems. Physical contact triggers a change in a switching quantity, which is then converted into an electrical signal and sent to the controller. The controller then uses the received signal to stop the motor.

[0003] Existing greenhouses consist of a greenhouse film, an arched support frame, and a rolling shutter machine. In winter, cotton blankets are used to regulate light and heat. To prevent the blankets from rolling excessively to the bottom, a vertical pole-type lower limit sensor is used, fixed to the front edge of the greenhouse bottom with angle iron or steel pipe, and a spring sensor is installed at the top. When the blanket touches the spring, the sensor cuts off the power to the rolling shutter machine, preventing over-rolling. However, the spring in the limiter has a short lifespan due to metal fatigue caused by the spring's expansion and contraction, making it prone to malfunction. Furthermore, current mercury sensors are easily triggered by external interference, causing the blanket-laying system to issue incorrect commands and affecting the efficiency of the greenhouse blanket-laying process. Utility Model Content

[0004] In view of this, this application proposes a limit sensor device and a greenhouse cotton quilt spreading system.

[0005] According to one aspect of this application, a limit sensor device is provided, comprising: a housing, a circuit board, and a mercury switch;

[0006] The shell is a hollow cuboid structure;

[0007] The circuit board is disposed inside the housing and located at the bottom of the housing;

[0008] The mercury switch is disposed inside the housing. The mercury switch is a hollow cylindrical structure and is longitudinally disposed on the circuit board.

[0009] The mercury switch has a mercury bead inside, which can flow along the length of the mercury switch column. The bottom of the mercury switch is connected to the circuit board via a wire, and the top of the mercury switch extends upward.

[0010] The number of mercury switches is two or more, and any two adjacent mercury switches are connected in series. The multiple mercury switches are suitable for transmitting electrical signals to the outside world.

[0011] In one possible implementation, a plurality of mercury switches are spaced apart within the housing, the mercury switches having a columnar structure, and the plurality of mercury switches are arranged relatively parallel to each other.

[0012] In one possible implementation, the mercury switch has an electrical contact at its bottom, the electrical contact being located at the center of the mercury switch, and one end of the electrical contact being electrically connected to the circuit board via the wire, while the other end of the electrical contact is adapted to electrically connect to the mercury bead corresponding to the mercury switch.

[0013] In one possible implementation, it further includes: a limiting block; the limiting block is disposed inside the housing and is sleeved on the mercury switch to limit the position of the mercury switch inside the housing.

[0014] In one possible implementation, it further includes: a connector; one end of the connector is inserted into any side wall of the housing and is electrically connected to the mercury switch, and the other end of the connector extends outward along the outer periphery of the housing, suitable for transmitting electrical signals to the outside.

[0015] In one possible implementation, the number of mercury switches is two, and the two mercury switches are symmetrically arranged about the center line of the terminal block.

[0016] Another aspect of this application discloses a greenhouse cotton quilt rolling system, comprising: a fixing plate and the aforementioned limiting sensor device;

[0017] The fixing plate is a long strip structure, suitable for laying along the rolling direction of the greenhouse quilt, and the fixing plate can be bent as the greenhouse quilt is rolled up; one end face of the fixing plate is suitable for fitting against the greenhouse quilt, and the other end face of the fixing plate is provided with the mercury switch; and the fixing plate and the circuit board are arranged opposite to each other on both sides of the corresponding mercury switch.

[0018] The number of the limit sensor devices is two or more, and the multiple limit sensor devices are spaced apart along the length direction of the fixed plate, and the top plate of the limit sensor device is located close to the fixed plate.

[0019] Specifically, when the greenhouse quilt is in an unfolded state, two or more of the limiting sensor devices are in a disconnected state; when the greenhouse quilt is in a rolled-up state, at least one of the limiting sensor devices is in a connected state.

[0020] In one possible implementation, multiple limit sensor devices are connected in parallel.

[0021] In one possible implementation, a plurality of the limit sensor devices are arranged parallel to each other on the fixed plate, and the limit sensor devices are installed in the same direction.

[0022] In one possible implementation, there are three limit sensor devices, and when the greenhouse quilt is rolled up, the interval angle between any two adjacent limit sensor devices is 120 degrees.

[0023] The beneficial effects of this application are:

[0024] The limit sensor device of this application has a simple structure, high sensitivity, and high integration. Firstly, a mercury switch is incorporated into the limit sensor device. When the housing tilts and rotates, the mercury switch inside the housing moves to a specific position, thereby electrically connecting the mercury switch to the circuit board and closing the circuit, thus indicating the current rolled-up state of the greenhouse quilt. Specifically, since the mercury droplets can flow within the columnar structure of the mercury switch, when the limit sensor rotates, the mercury droplets fall to the bottom of the mercury switch. These droplets are electrically connected to the circuit board via wires, thus conducting electricity and transmitting electrical signals to the outside. When the limit sensor rotates another 180 degrees, the mercury droplets fall to the top of the mercury switch. Because the circuit board is located at the bottom of the housing, the mercury droplets cannot conduct electricity to the circuit board via wires, thus preventing the transmission of electrical signals. Therefore, the location of the mercury switch structure is determined by the electrical signals transmitted by the limit sensor. Furthermore, compared to traditional spring limit sensors, the limit sensor device of this application does not experience metal deformation. Therefore, the limit sensor device of this application will not experience limit switch malfunction and has higher sensitivity. Furthermore, the limit sensor device of this application incorporates two or more mercury switches, which are spaced a certain distance apart. Adjacent mercury switches are electrically connected, and the two mercury switches are connected in series via a lower circuit board. If one mercury switch fails, the entire limit sensor device will cease operation, ensuring the safety of the limit sensor device and preventing direct short circuits in the internal wiring.

[0025] The greenhouse quilt rolling system of this application is simple to set up and more flexible. Limit sensor devices are installed at intervals along the length of a fixed plate, which is then encircled around the greenhouse quilt. When the quilt is laid flat, the limit sensor devices on the fixed plate are in an open state, unable to transmit electrical signals, because the circuit board and the fixed plate are positioned opposite each other on either side of the mercury switch. As the quilt is gradually rolled up, the mercury switch in the limit sensor device tilts, causing mercury beads that were initially far from the circuit board to gradually approach it until they reach the electrical contacts of the mercury switch. This allows the mercury beads in the switch to conduct through wires to the circuit board, closing the circuit and transmitting electrical signals. At this point, the circuit boards are electrically connected, transmitting information about the quilt rolling status. Furthermore, when the quilt is laid flat, the mercury switches in the multiple limit sensor devices are disconnected from the circuit board, allowing the circuit board to promptly stop the quilt rolling process.

[0026] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0027] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0028] Figure 1 This diagram shows the internal structure of a limit sensor device according to an embodiment of this application.

[0029] Figure 2 This diagram shows a schematic of the housing of the limit sensor device according to an embodiment of this application;

[0030] Figure 3 This diagram shows the closed configuration of the mercury switch according to an embodiment of this application;

[0031] Figure 4 This shows a rear view of the limit sensor device according to an embodiment of this application;

[0032] Figure 5 This diagram illustrates the structure of the greenhouse quilt rolling system according to an embodiment of this application.

[0033] Figure 6 This diagram illustrates the principle of the greenhouse quilt rolling system according to an embodiment of this application. Detailed Implementation

[0034] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0035] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application or to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0038] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0039] like Figures 1-4 As shown, the limit sensor device includes: a housing 1, a circuit board 5, and a mercury switch 3; the housing 1 is a hollow cuboid structure; the circuit board 5 is disposed inside the housing 1 and located at the bottom of the housing 1; the mercury switch 3 is disposed inside the housing 1, and the mercury switch 3 is a hollow columnar structure, which is longitudinally disposed on the circuit board 5; the mercury switch 3 has mercury beads inside, which can flow along the columnar length of the mercury switch 3, and the bottom end of the mercury switch 3 is connected to the circuit board 5 via a wire, and the top end of the mercury switch 3 extends upward; there are two or more mercury switches 3, and any two adjacent mercury switches 3 are connected in series, and multiple mercury switches 3 are suitable for transmitting electrical signals to the outside.

[0040] The limit sensor device of this embodiment has a simple structure, high sensitivity, and high integration. First, a mercury switch 3 is installed in the limit sensor device. When the housing 1 tilts and rotates, the mercury switch 3 inside the housing 1 moves to a specific position, thereby electrically connecting the mercury switch 3 to the circuit board 5, and the circuit is closed, thus obtaining the current rolled-up state of the greenhouse quilt. Specifically, since the mercury beads can flow in the columnar structure of the mercury switch 3, when the limit sensor rotates, the mercury beads fall to the bottom of the mercury switch 3. These mercury beads are electrically connected to the circuit board 5 through wires, thus conducting electricity and transmitting electrical signals to the outside. When the limit sensor rotates another 180 degrees, the mercury beads fall to the top of the mercury switch 3. Since the circuit board 5 is located at the bottom of the housing 1, the mercury beads cannot conduct electricity to the circuit board 5 through wires, thus preventing the transmission of electrical signals to the outside. Therefore, the location of the mercury switch 3 structure is determined by the electrical signals transmitted to the outside by the limit sensor. Compared to traditional spring-loaded limit sensors, the limit sensor device of this application does not experience metal deformation. Therefore, the limit sensor device of this application does not suffer from limiter malfunction and has higher sensitivity. Furthermore, the limit sensor device of this application incorporates two or more mercury switches 3, with a certain distance maintained between them. Adjacent mercury switches 3 are electrically connected, and the two mercury switches are connected in series using the lower circuit board 5. If one mercury switch 3 malfunctions, the entire limit sensor device will not operate, ensuring the safety of the limit sensor device and preventing direct short circuits in the internal wiring. It should be noted that the preset distance between the circuit board 5 and the mercury switches 3, as well as the set distance between any two adjacent mercury switches 3, needs to be determined based on the actual tilt situation. The mercury switches 3 can connect or disconnect the circuit at specific angles or positions. It should also be noted that when one mercury switch 3 is mistakenly connected due to external interference, the other mercury switches 3 can remain in normal operation, thus preventing electrical connection with the circuit board 5 and the issuance of erroneous commands.

[0041] In one specific embodiment, a plurality of mercury switches 3 are spaced apart inside the housing 1. The mercury switches 3 have a columnar structure and are arranged in parallel relative to each other.

[0042] In one specific embodiment, the mercury switch 3 has an electrical contact at its bottom, which is located at the center of the mercury switch 3. One end of the electrical contact is electrically connected to the circuit board 5 via a wire, and the other end of the electrical contact is used to electrically connect to the mercury bead inside the corresponding mercury switch 3. In this embodiment, it should be noted that, preferably, the multiple mercury switches 3 are arranged in a rectangular array, that is, the distance from the bottom of the mercury switch 3 to the circuit board 5 is equal, and the tops of the mercury switches 3 are flush.

[0043] In one possible implementation, there are two mercury switches 3, symmetrically arranged about the center line of the connector. In this embodiment, it should be noted that there are two mercury switches 3, and the distances from both mercury switches 3 to the connector 2 are equal. Furthermore, the distances from both mercury switches 3 to the circuit board 5 are equal. This makes the limit sensor device more symmetrical and balanced in structure. The symmetrical position of the two mercury switches 3 helps reduce detection errors caused by positional deviations. The symmetrical layout also helps improve the consistency of the sensor's response in different directions and angles, thereby enhancing the overall performance stability of the limit sensor device.

[0044] In one specific embodiment, the device further includes a connector 2; one end of the connector 2 is inserted into any side wall of the housing 1, and the connector 2 extends outward along the outer periphery of the housing 1, suitable for electrically connecting to the mercury switch 3. One end of the connector 2 is electrically connected to the mercury switch, and the other end transmits an electrical signal to the outside through a splitter. In this embodiment, it should be noted that a mounting hole is provided on the side wall of the housing 1 away from the circuit board 5, and the mounting hole is located in the lower middle part of the housing 1. The connector 2 is fixedly connected to the housing 1 through the mounting hole. It should be noted that the housing 1 is composed of a top plate, a bottom plate 11, and four side plates, wherein the bottom plate 11 is detachably connected to the other side plates. The mercury switch 3, the limit block, the circuit board 5, and the connector 2 are installed inside the housing 1, and then the bottom plate 11 is fixed to encapsulate the entire limit sensor device.

[0045] In one specific embodiment, the device further includes a limiting block 5. The limiting block 5 is disposed inside the housing 1 and is sleeved on the mercury switch 3, restricting the position of the mercury switch 3 within the housing 1. Two through holes 51 are formed in the limiting block 5 corresponding to the mercury switch 3, and the two through holes 51 are matched to the size of the mercury switch 3, with the mercury switch 3 inserted into the through holes 51. It should be further noted that the mercury switch 3, the limiting block 5 sleeved on the mercury switch 3, and the connector 2 are arranged opposite each other on both sides of the housing 1, maintaining a harmonious layout of the entire limit sensor device and thus ensuring the stability of the entire limit sensor device.

[0046] Without the limit block 5, the mercury switch 3 might move excessively due to external impacts or vibrations, leading to false triggering or damage. The presence of the limit block 5 effectively prevents this from happening, protecting the stability and reliability of the mercury switch 3. In some applications, such as automated equipment or industrial production lines, limit sensor devices need to ensure that they are triggered only at specific positions or angles. The presence of the limit block 5 prevents false triggering caused by misoperation or external interference, thereby improving the safety and reliability of the system.

[0047] Furthermore, it should be noted that the system also includes a screw plug 7, which matches the mounting hole and is inserted into the mounting hole to seal the housing 1. In this embodiment, a screw 4, specifically an M1.5 self-tapping screw, is also provided. The gap between the connector 2 and the mounting hole can be directly sealed with sealant. The screw plug 7 fits tightly into the mounting hole, effectively sealing the internal space of the housing 1 after insertion and tightening, preventing leakage of mercury or other media due to external pressure, temperature changes, or vibration. This sealing is crucial for maintaining the stability of the sensor's internal environment and protecting internal components from external contamination.

[0048] In one specific embodiment, the housing 1 has a cuboid structure, and the corners of the housing 1 are rounded. This prevents the corners of the housing 1 from bumping into or injuring the user, thus improving the safety of the limit sensor device. Specifically, with... Figure 1 The top and bottom directions are the width directions of shell 1, with Figure 2 The upper and lower directions are the height directions of shell 1, with Figure 2 The left and right directions are the length directions of housing 1. The width of housing 1 is 20cm, the length of housing 1 is 22cm, the height of housing 1 is 24cm, and the length of connector 2 is 70cm.

[0049] like Figure 3 As shown, in one specific embodiment, one end of the connector 2 is connected to the interior of the housing 1, and the other end is provided with a wire storage box 8, which contains a wire. In this embodiment, it should be noted that the wire storage box 8 contains a wire that can be electrically connected to the mercury switch 3, thereby enabling the controller to be electrically connected to the limit sensor device.

[0050] The greenhouse quilt rolling system includes: a fixing plate 10 and the aforementioned limit sensor device 20; the fixing plate 10 is a long strip structure, suitable for laying along the rolling direction of the greenhouse quilt, and the fixing plate 10 can bend as the greenhouse quilt is rolled up; one end face of the fixing plate 10 is suitable for fitting against the greenhouse quilt, and the other end face of the fixing plate 10 is provided with a mercury switch; and the fixing plate 10 and the circuit board are arranged opposite each other on both sides of the corresponding mercury switch; the number of limit sensor devices 20 is two or more, and the multiple limit sensor devices 20 are spaced apart along the length direction of the fixing plate 10, and the top plate of the limit sensor device 20 is close to the fixing plate 10; specifically, when the greenhouse quilt is in the unfolded state, two or more limit sensor devices 20 are in the disconnected state, and when the greenhouse quilt is in the rolled-up state, at least one limit sensor device 20 is in the connected state.

[0051] The greenhouse quilt spreading system proposed in this embodiment is simple to set up and more flexible. Limit sensor devices 20 are installed at intervals along the length of a fixing plate 10, which is then encircled around the greenhouse quilt. When the quilt is rolled up, the mercury switch 3 in the limit sensor device 20 tilts, causing the mercury switch 3 to be in a closed state with the controller, and thus with the circuit board 5. At this time, the circuit board 5 is electrically connected to the controller, transmitting the quilt rolling status to the controller. When the mercury switch 3 in the limit sensor device 20 tilts again, it disconnects from the controller, and also disconnects from the circuit board 5, allowing the quilt controller circuit board to stop working promptly. Specifically, when the greenhouse quilt is laid flat, since the circuit board 5 and the fixing plate 10 are positioned opposite each other on either side of the mercury switch 3, the limit sensor devices 20 on the fixing plate 10 are all in a disconnected state and cannot transmit electrical signals to the outside. As the greenhouse quilt is gradually rolled up, the mercury switch 3 in the limit sensor device 20 tilts, causing the mercury beads that were originally far away from the circuit board 5 to gradually approach the circuit board 5 until the mercury beads flow to the electrical contacts of the mercury switch 3. This allows the mercury beads in the mercury switch 3 to conduct through the wires to the circuit board 5, and the mercury switch 3 and the circuit board 5 are in a closed state, transmitting electrical signals to the outside.

[0052] like Figure 5 and Figure 6 As shown, in one specific embodiment, multiple limit sensor devices 20 are connected in parallel. In this embodiment, it should be noted that as long as one limit sensor device 20 is connected, the entire greenhouse quilt spreading system is in a connected state, thus enabling timely determination of the quilt's rolling and spreading status.

[0053] In one specific embodiment, multiple limit sensor devices 20 are arranged parallel to each other on the fixed plate 10, and the limit sensor devices 20 are installed in the same direction. In this embodiment, it should be noted that "installed in the same direction" means that the limit sensor devices 20 are located on the same surface of the fixed plate 10, so that when the greenhouse quilt is rolled up, the other surface of the fixed plate 10 without limit sensor devices 20 is in closer contact with the greenhouse quilt, thus accurately determining whether the greenhouse quilt is rolled up or laid flat. Specifically, during use, the mercury switch 3 moves inside the limit sensor device 20, disconnecting or connecting the limit sensor device 20 to the controller. The limit sensor devices 20 are installed in the same direction, and preferably there are three limit sensor devices 20. Therefore, when the greenhouse quilt is in a rolled-up state, at least two of the limit sensor devices 20 will have mercury switches 3 moving in similar directions, thus determining that the greenhouse quilt is in a rolled-up state. When the greenhouse quilt is fully spread out, the three limit sensor devices 20 are on the same straight line, and the mercury switches 3 in the three limit sensor devices 20 are in the same position and are all disconnected, so it can be determined that the greenhouse quilt is spread out.

[0054] In one specific embodiment, there are three limit sensor devices 20, and when the greenhouse quilt is rolled up, the angle between any two adjacent limit sensor devices 20 is 120 degrees. In this embodiment, it should be noted that there are multiple limit sensor devices 20, and a preset distance is provided between the multiple limit sensor devices 20. Preferably, this application uses three limit sensor devices 20, and when the greenhouse quilt is rolled up, the three limit sensor devices 20 are arranged in a ring at equal intervals on the outer periphery of the greenhouse quilt, and preferably, the angle between any adjacent limit sensor devices 20 with a preset distance is 120 degrees.

[0055] In one specific embodiment, it should be noted that multiple fixing boxes 30 are provided on the same side of the fixing plate 10, and the number of fixing boxes 30 matches the number of limit sensor devices 20, with equal distance between any two adjacent fixing boxes 30. The fixing plate 10 is a long strip structure, with multiple mounting holes along its length, allowing the fixing plate 10 to be fixed by wrapping it with steel wire along the rolling direction of the greenhouse quilt, and also allowing the fixing boxes 30 for mounting the limit sensor devices 20 to be fixed by wrapping them with steel wire along the length of the fixing plate 101. Furthermore, the fixing plate 10 is made of a deformable material, such as metal. Thus, the fixing plate 10 can be arranged in a ring shape along the rolling direction of the quilt. During the rolling process of the greenhouse quilt, the mercury switch 3 inside the limit sensor device 20 moves with the rolling of the quilt, thereby determining the rolling status of the greenhouse quilt by acquiring the connection / disconnection relationship between the limit sensor device 20 and the external controller.

[0056] In one specific embodiment, it should be noted that the fixing plate 10 is located at one end of the rolled-up greenhouse quilt, that is, the fixing plate 10 is located at the edge of the rolled-up greenhouse quilt. Alternatively, the fixing plate 10 can be located in the middle of the rolled-up greenhouse quilt to determine whether the greenhouse quilt is fully unfolded.

[0057] It should be noted that although the limit sensor device and the greenhouse quilt rolling system have been described above as examples, those skilled in the art will understand that this application is not limited to these. In fact, users can flexibly set parameters according to their personal preferences and / or actual application scenarios, as long as it is reasonable.

[0058] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A position-limiting sensor device, characterized by include: The housing, circuit board, and mercury switch; the housing is a hollow cuboid structure. The circuit board is disposed inside the housing and located at the bottom of the housing; The mercury switch is disposed inside the housing. The mercury switch is a hollow cylindrical structure and is longitudinally disposed on the circuit board. The mercury switch has a mercury bead inside, which can flow along the length of the mercury switch column. The bottom of the mercury switch is connected to the circuit board via a wire, and the top of the mercury switch extends upward. The number of mercury switches is two or more, and any two adjacent mercury switches are connected in series. The multiple mercury switches are suitable for transmitting electrical signals to the outside world.

2. The position-limit sensor apparatus according to claim 1, characterized in that Multiple mercury switches are spaced apart within the housing. Each mercury switch has a columnar structure and is arranged in parallel relative to each other.

3. The position-limit sensor apparatus according to claim 1, wherein The mercury switch has an electrical contact at its bottom, which is located at the center of the mercury switch. One end of the electrical contact is electrically connected to the circuit board via the wire, and the other end of the electrical contact is used to electrically connect to the mercury bead inside the mercury switch.

4. The position-limit sensor apparatus according to claim 1, characterized in that Also includes: Limit block; The limiting block is disposed inside the housing and is sleeved on the mercury switch to restrict the position of the mercury switch inside the housing.

5. The position-limit sensor apparatus according to claim 1, characterized by Also includes: Connector; One end of the connector is inserted into any side wall of the housing and is electrically connected to the mercury switch. The other end of the connector extends outward along the outer periphery of the housing and is suitable for transmitting electrical signals to the outside.

6. The position-limit sensor apparatus according to claim 5, wherein The number of mercury switches is two, and the two mercury switches are symmetrically arranged about the center line of the terminal block.

7. A system for spreading a cotton quilt in a greenhouse, characterized in that, include: The fixing plate and the limit sensor device according to any one of claims 1-6; The fixing plate is a long strip structure, suitable for laying along the rolling direction of the greenhouse quilt, and the fixing plate can be bent as the greenhouse quilt is rolled up. One end face of the fixing plate is adapted to fit against the greenhouse quilt, and the other end face of the fixing plate is provided with the mercury switch; and the fixing plate and the circuit board are arranged opposite to each other on both sides of the corresponding mercury switch; The number of the limit sensor devices is two or more, and the multiple limit sensor devices are spaced apart along the length direction of the fixed plate; Specifically, when the greenhouse quilt is in an unfolded state, two or more of the limiting sensor devices are in a disconnected state; when the greenhouse quilt is in a rolled-up state, at least one of the limiting sensor devices is in a connected state.

8. The system of claim 7, wherein, Multiple limit sensor devices are connected in parallel.

9. The system of claim 7, wherein, Multiple limit sensor devices are arranged parallel to each other on the fixed plate, and the limit sensor devices are installed in the same direction.

10. The system of claim 7, wherein, There are three limit sensor devices, and when the greenhouse quilt is rolled up, the interval angle between any two adjacent limit sensor devices is 120 degrees.

Images