A watertight limiting device suitable for polar ice environment

Abstract

The application relates to the field of limit switches, in particular to a watertight limit device suitable for polar ice region environment, which mainly comprises a box body, a limit switch, a sealing cylinder sleeve and a linkage mechanism. The inner cavity of the box body is vertically isolated into a transmission cabin and a sealing cabin, the limit switch is installed in the sealing cabin, the sealing cylinder sleeve is connected at a through hole, the linkage mechanism comprises a contact swing lever and a lifting rod, the contact swing lever is installed in the transmission cabin, the contact swing lever has a first rod part and a second rod part which are separated on the two sides of a fulcrum, one end of the first rod part extends out of the transmission cabin, the lifting rod is arranged in the sealing cylinder sleeve, the upper end of the lifting rod is connected with a trigger swing arm, and the lower end of the lifting rod is hinged with the first rod part of the contact swing lever. The downward swing of the contact swing lever drives the lifting rod to slide upward in the sealing cylinder sleeve, drives the trigger swing arm to rotate to trigger the limit switch, and the limit device has the advantages that the risk of electrical immersion short circuit and icing jam of the limit switch under the polar water working condition can be greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of limit switch technology, and in particular to a watertight limit device suitable for polar ice environments. Background Technology

[0002] In the field of shipbuilding and marine engineering, lifting machinery installed on the outside of open decks (such as lifeboat davits, cargo handling cranes, etc.) is a key piece of equipment to ensure the safety of ship operations. Highly reliable limit devices must be installed at the end of their travel to protect the vessel's stroke. Ships adapted to navigation in polar ice regions face extremely harsh combined conditions during operation, including dynamically changing waterlines, prolonged extreme low temperatures (such as -30°C to -40°C), and sea ice and seawater splash.

[0003] Currently, marine travel limit devices in this field typically employ a fixed installation scheme, directly exposing the limit switch to the hull structure or mechanical support. However, this design, which exposes the limit switch directly to the external environment, has inherent flaws in actual operation in polar ice regions and is ill-suited to the harsh polar conditions. Firstly, due to significant dynamic changes in the ship's draft under different loading conditions or wave action, the directly exposed limit switch is highly susceptible to frequent seawater inundation. Once seawater seeps into the limit switch, it directly causes electrical short circuits and functional failure. Secondly, under the long-term alternating effects of extreme low temperatures and seawater splashes, the limit switch body and its external mechanical actuation structures (such as the trigger arm and shaft) directly exposed to the polar environment will rapidly freeze after being wetted by the ice-water mixture. As the ice thickness increases and the ice expansion effect occurs, the mechanical components of the limit switch will freeze and become jammed. This mechanical jamming prevents the limit switch from sensing and transmitting travel signals, ultimately leading to the related lifting machinery operating without protection for extended periods, posing a significant safety hazard.

[0004] In view of this, how to change the current situation where limit switches are directly exposed to the external environment, so as to achieve waterproof and anti-icing protection for the limit switches, while ensuring that the contact signals of external mechanical movement are reliably transmitted to the limit switches, thereby ensuring the stable triggering and reliable operation of the limit device in the polar environment, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a watertight limiting device suitable for polar ice environments. This limiting device has the advantage of significantly reducing the risk of electrical short circuits and icing jamming of the limit switch under polar water conditions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A watertight limiting device suitable for polar ice environments includes: a housing, the inner cavity of which is vertically separated into a lower transmission chamber and an upper sealed chamber, the sealed chamber being a closed, independent cavity with a through hole at its bottom; a limit switch installed inside the sealed chamber, the limit switch having a trigger swing arm; a sealing cylinder sleeve, one end of which is threadedly connected to the through hole and the other end extending vertically into the transmission chamber; and a linkage mechanism including a contact swing arm and a lifting rod; the contact swing arm is installed inside the transmission chamber in a manner that allows it to swing up and down around a set fulcrum, and the... The contact lever has a first rod portion and a second rod portion separated on both sides of the set fulcrum. One end of the second rod portion extends out of the transmission chamber, allowing an external object to collide with it and trigger the limit switch. The lifting rod is slidably inserted into the sealed cylinder sleeve, and the two are dynamically sealed together. Its upper end extends into the sealed chamber and is connected to the triggering swing arm, and its lower end extends into the transmission chamber and is hinged to the first rod portion of the contact lever. The downward swing of the contact lever drives the lifting rod to slide upward within the sealed cylinder sleeve, driving the triggering swing arm to rotate and trigger the limit switch.

[0007] To optimize the above plan, the following measures were also taken: As a preferred embodiment, the trigger arm is configured to swing about a set axis and has two symmetrical joints about the set axis. Two sets of sealing cylinder liners are provided. The linkage mechanism includes two lifting rods that can slide up and down through the two sealing cylinder liners respectively. The lower end of one lifting rod is hinged to the first rod portion of the contact rocker arm, and the lower end of the other lifting rod is hinged to the second rod portion. The upper ends of the two lifting rods are respectively hinged to the two joint portions. The two lifting rods, the trigger rocker arm, and the contact rocker arm together form a parallelogram mechanism.

[0008] As one of the preferred embodiments, the lifting rod is provided with an annular piston ring on the rod body inside the sealing cylinder sleeve. The outer circumferential surface of the piston ring slides and seals with the inner wall of the sealing cylinder sleeve, and divides the hollow inner cavity of the sealing cylinder sleeve into an upper chamber located above it and a lower chamber located below it. The upper chamber is provided with a spring sleeved on the outside of the lifting rod for resetting the lifting rod. The two ends of the spring abut against the top inner wall of the sealing cylinder sleeve and the top surface of the piston ring, respectively.

[0009] As a preferred embodiment, it also includes an antifreeze tank, a pressure tank, and an operating nozzle, wherein the antifreeze tank and the pressure tank are located in the transmission compartment; The lower chambers in both sets of the sealing cylinder liners have an inlet and an outlet. In the non-de-icing state, the inlet and outlet of the lower chamber are both closed. In the de-icing state, the inlet of the lower chamber is connected to the antifreeze reservoir via a pipe, and the pipe is equipped with an inlet check valve to limit the unidirectional flow of antifreeze from the antifreeze reservoir to the lower chamber; the outlet of the lower chamber is connected to the pressure tank via a pipe, and the pipe is equipped with an outlet check valve to limit the unidirectional flow of antifreeze from the lower chamber to the pressure tank. The pressure tank's output port is connected to the operating nozzle via a flexible hose, and a switch valve is provided between them; in non-de-icing mode, the operating nozzle is stored in the transmission compartment.

[0010] As one preferred embodiment, the sealing cylinder liner includes a body and a sealing nut connected to the bottom end of the body by threads. The body includes an integrally formed inner section and a sleeve section. The outer wall of the inner section has external threads and is threadedly connected to the through hole. The upper end face of the sleeve section abuts against the outer surface of the bottom of the sealing chamber. The lower end of the sleeve section is connected to the sealing nut. The sealing nut has a movable hole in the middle for the lifting rod to pass through. An O-ring is provided between the inner wall of the movable hole and the outer wall of the lifting rod.

[0011] As a preferred embodiment, an O-ring is provided between the upper end face of the sleeve section and the sealing chamber, surrounding the through hole; an O-ring is provided around the lifting rod on the inner wall of the inner section; and an O-ring is provided between the sealing nut and the lower end face of the sleeve section, surrounding the inner cavity of the sealing cylinder liner.

[0012] As one preferred embodiment, the sleeve section includes an inner sleeve and an outer sleeve arranged concentrically, and an annular first heating blanket sandwiched between the outer wall of the inner sleeve and the inner wall of the outer sleeve. The first heating blanket is used to conduct heat to heat the inner sleeve and the lifting rod inserted therethrough. A second heating blanket is laid on the inner side wall surface of the sealed chamber for heating the inner cavity of the sealed chamber. A temperature control power supply is provided on the outer side wall of the sealed chamber, and the temperature control power supply is electrically connected to both the second heating blanket and the first heating blanket.

[0013] As a preferred embodiment, the linkage mechanism further includes a vertical support rod located at the bottom of the transmission compartment. The contact swing rod is supported on the top of the support rod and can swing up and down. A roller is provided at the end of the contact swing rod that extends out of the transmission compartment.

[0014] As a preferred embodiment, one side surface of the sealed chamber is provided with an installation port for the limit switch to be inserted and installed, and the edge of the installation port is sealed with a cover plate for closing the installation port by fasteners; the top of the box is provided with a stuffing box that communicates with the inner cavity of the sealed chamber.

[0015] As a preferred embodiment, a connecting plate is fixed on the outer wall of the box body near the ship carrier. The surface of the connecting plate has multiple connecting holes, and fixing bolts for fastening the box body to the ship deck are inserted into the multiple connecting holes.

[0016] Because of the above-described solutions, one or more technical solutions provided in this application embodiment have at least the following technical effects or advantages: As one aspect, to avoid exposing the limit switch, the limit device uses a partition to separate the upper and lower parts of the housing. The upper part is a fully enclosed sealed chamber, where the limit switch body is installed to achieve waterproof and anti-icing isolation protection for the limit switch body. The lower part is a transmission chamber, mainly used to install the linkage mechanism and provide the space required for linkage. Specifically, in order to transmit the triggering action of the lower part to the upper part, a sealed cylinder sleeve and a lifting rod that slides and seals with the inner cavity of the sealed cylinder sleeve are set at the through hole of the partition. The bottom end of the lifting rod is hinged to the contact swing rod. When external machinery touches the contact swing rod, the swing rod pushes the lifting rod to slide upward in the sealed cylinder sleeve. The upper end of the lifting rod passes through the sealed cylinder sleeve, driving the trigger swing arm in the sealed chamber to rotate, thereby triggering the switch. Compared to existing technologies, the upper and lower compartments achieve spatial isolation between the switching elements and the external water environment, cutting off the path for seawater to enter the switch body and cause a short circuit. At the same time, at the waterproof interface between the inner and outer compartments, the vertical linear sliding of the lifting rod replaces the traditional rocker arm shaft rotation transmission to trigger the switch. When the lifting rod makes axial reciprocating motion, under the obstruction of the sealing cylinder and the gravity of ice, the sealing cylinder will scrape and push away the ice on the surface of the rod along the axial direction, instead of continuously rolling hard ice into the waterproof interface, such as the sealing ring, causing it to cut in place and tear the sealing ring and leak water. This ensures reliable and highly watertight cross-compartment transmission of contact displacement.

[0017] On another front, the linkage mechanism has a lifting rod hinged to the first and second rods, respectively, and the lifting rods are connected to the joints on both sides of the trigger swing arm, forming a parallelogram linkage mechanism. When the contact swing arm is forced to swing downward, based on the lever principle, the connecting rods on both sides of the fulcrum produce opposite displacements, one up and one down. This displacement forces one side of the lifting rod to generate an upward thrust, while simultaneously pulling the other side of the lifting rod to generate a downward pull. The two opposing forces are applied to the trigger swing arm at the same time, forming a torque couple that works together. If the sliding resistance of one side of the lifting rod increases sharply due to icing, the opposing force output by the other side of the lifting rod can directly assist it in overcoming the local freezing resistance through the rigid connecting rod, thus forming a bidirectional push-pull power redundant transmission structure. When one side of the lifting rod is frozen and stuck, the torque compensation on the other side can forcibly break the freezing resistance, avoiding the risk of a single transmission rod being easily frozen and locked, and ensuring rigid linkage triggering under extreme freezing conditions.

[0018] On the other hand, when de-icing and cleaning of the limiting device is required, the lower chamber within the sealed cylinder liner can be used as a pumping chamber. An antifreeze cleaning flow path is established through pipelines and check valves. By operating the contact lever, the lifting rod moves up and down reciprocally, thereby moving the piston rings. The upward movement of the piston rings increases the volume of the lower chamber, creating negative pressure. Antifreeze is drawn in from the storage tank through the input check valve. The downward movement of the piston rings compresses the lower chamber, and the antifreeze is forced into the pressure tank through the output check valve for pressure storage. During de-icing, the operating nozzle is removed and aimed at the area requiring de-icing, such as the exposed section of the contact lever or the exposed section of the lifting rod. The switch valve is opened, and the contact lever continues to swing up and down. The high-pressure fluid accumulated in the pressure tank is sprayed through pressure nozzles on both sides to flush away the ice layer. After one operation, the operating nozzle can be retracted into the transmission compartment, the switch valve closed, and the corresponding pipelines and check valves removed. This achieves self-driven pressure storage de-icing without an external electric pump, requiring only periodic antifreeze replenishment, greatly improving the convenience of de-icing maintenance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only involve some embodiments of this application and should not be construed as limiting this application.

[0020] Figure 1 This is a schematic diagram of the internal structure of the watertight limiting device suitable for polar ice environments in Embodiment 1; Figure 2 This is a schematic diagram of the side structure of the watertight limiting device suitable for polar ice environments in Embodiment 1; Figure 3 This is a schematic diagram of the internal structure of the watertight limiting device suitable for polar ice environments in Embodiment 2 in the first state; Figure 4 This is a schematic diagram of the internal structure of the watertight limiting device suitable for polar ice environments in Embodiment 2 in the second state; Figure 5 This is a schematic diagram of the liquid circuit connection in Example 2.

[0021] Figure label: 1. Housing; 11. Transmission compartment; 111. Cover plate; 12. Sealing compartment; 13. Connecting plate; 14. Fixing bolt; 15. Stuffing gland; 2. Limit switch; 21. Mounting seat; 22. Trigger swing arm; 221. Joint; 3. Sealing cylinder liner; 30. Main body; 301. Inner section; 302. Sleeve section; 31. Upper chamber; 32. Lower chamber; 33. Sealing nut; 34. Spring; 4. Linkage mechanism; 41. Support rod; 42. Contact swing arm; 421. Roller; 43. Lifting rod; 431. Piston ring; 51. Antifreeze tank; 52. Pressure tank; 53a. Input check valve; 53b. Output check valve; 54. Operating nozzle; 541. Pressure nozzle; 57. Switch valve; 61. First heating blanket; 62. Second heating blanket; 63. Temperature control power supply; 7. O-ring seal. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings, so as to more clearly understand the purpose, features and advantages of this invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of this invention, but are only for illustrating the essential spirit of the technical solutions of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0023] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0024] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0025] The singular forms “a” and “the” used in this specification and the appended claims include plural references unless otherwise expressly stated herein. It should be noted that the term “or” is generally used to mean “and / or” unless otherwise expressly stated herein.

[0026] In the following description, in order to clearly demonstrate the structure and working method of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0027] The implementation details of embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following content is only for the convenience of understanding the implementation details and is not necessary for implementing this solution.

[0028] Example 1 refer to Figures 1 to 2 This embodiment provides a watertight limiting device suitable for polar ice environments. It aims to solve the problems of existing marine limit switches being exposed to the polar environment and easily susceptible to short circuits and functional failures due to seawater seepage caused by changes in the ship's draft, as well as the technical problem of mechanical transmission components freezing and jamming due to extreme cold and icing. It not only achieves absolute spatial isolation between the limit switch and the water environment, but also realizes icebreaking and active de-icing under conditions without external power through a push-pull linkage mechanism and a mechanical self-driven hydraulic de-icing mechanism, significantly improving the reliability of the limit device in extreme polar conditions.

[0029] Specifically, refer to Figures 1 to 2 The watertight limiting device suitable for polar ice environments specifically includes a housing 1, a limit switch 2, a sealing cylinder liner 3, and a linkage mechanism 4. The housing 1's internal cavity is vertically divided into a lower transmission chamber 11 and an upper sealing chamber 12 by a horizontal partition. The sealing chamber 12 is a closed, independent cavity with a through hole at its bottom. The limit switch 2 is installed inside the sealing chamber 12 and has a trigger swing arm 22 that can rotate around a set axis. One end of the sealing cylinder liner 3 is threaded to the through hole, and the other end extends vertically into the transmission chamber 11. The linkage mechanism 4 includes a support rod 41, a contact swing arm 42, and a lifting rod 43. The support rod 41 is a vertical rod located at the bottom of the transmission chamber 11. The contact swing arm 42... The contact swing rod 42 is positioned at the top of the support rod 41 in a manner that allows it to swing up and down around a set fulcrum. The contact swing rod 42 has a first rod portion and a second rod portion separated on both sides of the set fulcrum. One end of the second rod portion extends out of the transmission chamber 11, forming an exposed end, which is triggered by collision with an external object to activate the limit switch. The lifting rod 43 is slidably inserted into the sealing cylinder liner 3 and the two are dynamically sealed together. Its upper end extends into the sealing chamber 12 and is connected to the trigger swing arm 22. Its lower end extends into the transmission chamber 11 and is hinged to the first rod portion of the contact swing rod 42. The downward swing of the contact swing rod 42 drives the lifting rod 43 to slide upward within the sealing cylinder liner 3, thereby driving the trigger swing arm 22 to rotate and trigger the limit switch 2.

[0030] Specifically, the limit switch 2, also known as a travel switch, typically includes a mounting base 21 and a trigger swing arm 22 that can swing around a set axis within a set range on the mounting base 21. The set axis is vertically aligned with the set fulcrum. A torsion spring reset member is provided between the trigger swing arm 22 and the mounting base 21 to reset the trigger swing arm 22. The limit switch 2 realizes the switching between the internal contacts of the switch by rotating the trigger swing arm 22 within a certain range, that is, the triggering of the switch signal.

[0031] In this embodiment, the limit switch 2 is not directly installed on the hull structure and exposed to the polar environment. Instead, it is installed inside the sealed chamber 12. The limit switch 2 inside the sealed chamber 12 is then triggered by the linkage mechanism 4. Waterproofing and ice prevention are achieved through the sealing cooperation of the sealed chamber, the sealed cylinder liner 3, and the lifting rod 43. This is fundamentally different from the sealing and waterproofing measures adopted by the limit switch 2 itself. The internal structure of the limit switch 2 or the limit switch is known technology and will not be elaborated here.

[0032] Specifically, such as Figure 1 As shown, in one scenario, the top end of the lifting rod 43 abuts against the triggering swing arm 22. The downward swing of the contacting swing arm 42 drives the lifting rod 43 to slide upward within the sealing cylinder liner 3, pushing the triggering swing arm 22 to rotate clockwise, thereby triggering the limit switch 2.

[0033] Specifically, such as Figure 3 and Figure 4 As shown, in another scenario, the top end of the lifting rod 43 is hinged to the triggering arm 22, for example, via a pivot hinge. The downward swing of the contact arm 42 drives the lifting rod 43 to slide upward within the sealing cylinder liner 3, pushing the triggering arm 22 to rotate clockwise, thereby triggering the limit switch 2. In this case, the lifting rod 43 and the triggering arm 22 are inseparably connected, and the triggering arm 22 must rotate in sync with the lifting rod 43's upward and downward movement.

[0034] Both of the above methods can trigger the limit switch 2 inside the sealed chamber 12, and technicians can choose according to their needs.

[0035] Specifically, the exposed end of the contact lever is provided with a roller 421, which is used to contact and stop the target object, converting the sliding friction between the two into rolling friction, greatly reducing wear. Furthermore, the rolling contact allows the instantaneous impact force of the external lifting device touching the lever downward to be smoothly and seamlessly converted into the torque of the contact lever 42 swinging downward, ensuring the continuity and accuracy of the subsequent actions of the lifting rod 43 and the limit switch 2.

[0036] When the device is running, external equipment such as lifting machinery such as lifeboat davits and cargo loading and unloading cranes will touch the contact arm 42 downwards, driving the lifting rod 43 to slide upwards in a straight line against friction, thereby causing the trigger arm 22 to swing around the set axis, thus triggering the limit switch 2.

[0037] In summary, to prevent the limit switch 2 from being exposed, the limit device uses a partition to separate the upper and lower parts of the housing. The upper part is a fully enclosed sealed chamber 12, inside which the limit switch body is installed to achieve waterproofing, anti-icing, and other isolation protection for the limit switch body. The lower part is a transmission chamber 11, mainly used to install the linkage mechanism 4 and provide the space required for linkage. Specifically, to transmit the triggering action of the lower part to the upper part, a sealed cylinder sleeve 3 and a lifting rod 43 that slides and seals with the inner cavity of the sealed cylinder sleeve 3 are set at the through hole of the partition. The bottom end of the lifting rod 43 is hinged to the contact swing rod 42. When external machinery touches the contact swing rod 42, the swing rod pushes the lifting rod 43 to slide upward in the sealed cylinder sleeve 3. The upper end of the lifting rod 43 passes through the sealed cylinder sleeve 3, driving the triggering swing arm 22 in the sealed chamber 12 to rotate, thereby triggering the switch. Compared with the prior art, the upper and lower compartments achieve spatial isolation between the switch element and the external water environment, cutting off the path of seawater entering the switch body and causing a short circuit.

[0038] In existing technology, the rocker arm of the limit switch 2 is directly exposed to the external environment, and ice fragments or ice shards easily accumulate at the rocker arm's pivot. Typically, a sealing ring is installed between the pivot and the pivot hole. As the pivot rotates, ice fragments are easily drawn into the gap between the sealing ring and the pivot, causing wear or tear on the sealing ring, leading to water leakage inside the limit switch and causing short circuits or circuit failures. In this embodiment, at the waterproof interface between the inner and outer sides of the sealed chamber 12, a vertical linear sliding lifting rod 43 is used instead of the traditional rocker arm pivot rotation transmission trigger switch. When the lifting rod 43 reciprocates axially along the vertical direction, under the combined action of gravity and the obstruction of the sealing cylinder liner 3, the ice shards on the surface of the rod are scraped and pushed away axially downwards, preventing hard ice shards from being continuously drawn into the waterproof interface, such as at the sealing ring, causing in-situ cutting and tearing of the sealing ring, thus ensuring reliable and highly watertight cross-chamber transmission of the contact displacement.

[0039] Example 2 refer to Figures 3 to 4The difference between this embodiment and Embodiment 1 is that in this embodiment, the trigger swing arm 22 is configured to swing around a set axis and has two symmetrical joints 221 about the set axis. Two sets of sealing cylinder sleeves 3 are provided. The linkage mechanism 4 includes two lifting rods 43 that can slide up and down through the two sealing cylinder sleeves 3 respectively. The lower end of one lifting rod 43 is hinged to the first rod portion of the contact swing arm 42, and the lower end of the other lifting rod 43 is hinged to the second rod portion. The upper ends of the two lifting rods 43 are respectively hinged to the two joints 221. The two lifting rods 43, the trigger swing arm 22 and the contact swing arm 42 together form a parallelogram mechanism.

[0040] Specifically, the trigger swing arm 22 includes a rectangular body and joint portions 221 that are respectively protruding on both sides of the rectangular body. The joint portions 221 are hinged to the corresponding lifting rod 43, for example, by a pivot. Preferably, the joint portions 221 are semi-circular and coaxial with the pivot.

[0041] refer to Figures 3 to 4 As shown, in the first state, the contact lever 42 is not subjected to external force, and at this time, the triggering arm 22 of the limit switch 2 is in the reset position. In the second state, the contact lever 42 is forced to swing downward, and the triggering arm 22 is in the triggering position. In this embodiment, the linkage mechanism 4 uses the top of the support rod 41 as the fulcrum, and a lifting rod 43 passing through the sealing cylinder sleeve 3 is hinged to the first rod part and the second rod part respectively. The upper end of the lifting rod 43 is connected to the joint 221 on both sides of the triggering arm 22, forming a parallelogram linkage mechanism. When the contact lever 42 is forced to swing downward, based on the lever principle, the connecting rods on both sides of the fulcrum produce opposite displacements of one up and one down. The displacement forces one side of the lifting rod 43 to generate an upward thrust, while simultaneously pulling the other side of the lifting rod to generate a downward pull. The two opposing forces are applied simultaneously to the triggering swing arm 22, forming a torque couple that works together. If the sliding resistance of one side of the lifting rod 43 increases dramatically due to icing, the opposing force output by the other side of the lifting rod 43 can directly assist it in overcoming the local freezing resistance through the rigid connecting rod. This forms a bidirectional push-pull power redundant transmission structure. When one side is stuck due to icing, the torque compensation on the other side can forcibly break the icing resistance, avoiding the risk of a single transmission rod being easily frozen and locked, and ensuring rigid linkage triggering under extreme freezing conditions.

[0042] like Figures 3 to 4In this embodiment, the lifting rod 43 is provided with an annular piston ring 431 on the rod body inside the sealing cylinder sleeve 3. The outer circumferential surface of the piston ring 431 slides and seals with the inner wall of the sealing cylinder sleeve 3, and divides the hollow inner cavity of the sealing cylinder sleeve 3 into an upper chamber 31 located above it and a lower chamber 32 located below it. The upper chamber 31 is provided with a spring 34 sleeved on the outside of the lifting rod 43. The spring 34 is a cylindrical helical spring used to reset the lifting rod 43. The two ends of the spring 34 respectively abut against the top inner wall of the sealing cylinder sleeve 3 and the top surface of the piston ring 431.

[0043] Here, the piston ring 431 serves a dual function of isolation and mechanical guidance. In terms of mechanical guidance, when the contact rocker arm 42 is subjected to an external impact, the lifting rod 43 moves upward, and the piston ring 431 follows, compressing the spring 34 to store energy. After the impact is unloaded, the spring 34 releases its potential energy, driving the lifting rod 43 to return to its original position. At the same time, the displacement of the piston ring 431 within the cylinder liner, constrained by the dynamic seal, changes the physical volume of the lower chamber 32.

[0044] refer to Figure 5 As shown, to facilitate de-icing and cleaning of the limiting device, in this embodiment, the limiting device also includes an antifreeze tank 51, a pressure tank 52, and an operating nozzle 54. The antifreeze tank 51 and the pressure tank 52 are located inside the transmission compartment 11. The operating nozzle 54 is equipped with several pressure nozzles 541. The lower chambers 32 in both sets of sealing cylinder liners 3 have inlet and outlet ports. In the non-de-icing state, the inlet and outlet ports of the lower chambers 32 are sealed by plugs or covers. In the de-icing state, the inlet port of the lower chamber 32 is connected to the antifreeze tank 51. 1. The system is connected via a pipe, and the pipe is equipped with an input check valve 53a for limiting the unidirectional flow of antifreeze from the antifreeze reservoir 51 to the lower chamber 32. The output port of the lower chamber 32 is connected to the pressure tank 52 via a pipe, and the pipe is equipped with an output check valve 53b for limiting the unidirectional flow of antifreeze from the lower chamber 32 to the pressure tank 52. The output port of the pressure tank 52 is connected to the operating nozzle 54 via a flexible hose, and a switch valve 57 is provided between the two. In the non-de-icing state, the operating nozzle 54 is retracted and stored in the transmission compartment 11.

[0045] Specifically, each end of the pipe connecting the lower chamber 32 to the antifreeze tank 51 and the pressure tank 52, as well as the inlet and outlet, are provided with a matching quick-connect fitting for quick assembly and disassembly of the pipes between the non-de-icing state and the de-icing state.

[0046] In this embodiment, the limiting device has at least two states. In the non-de-icing state, i.e., in normal use, the inlet and outlet of the lower chamber 32 are sealed with plugs or covers, no liquid is left in the pipeline, and the operating nozzle 54 is also placed in the transmission chamber 11 for protection.

[0047] When de-icing is required, the operator removes the plug and connects the lower chamber 32 to the antifreeze reservoir 51 and the pressure tank 52 via a pipe equipped with a one-way valve. Then, by manually pushing and pulling the external contact lever 42 (or by jogging the lifting device to touch the lever), the lifting rod 43 reciprocates linearly within the sealed cylinder liner 3. The up-and-down movement of the piston ring 431 causes alternating compression and expansion of the lower chamber 32, continuously drawing antifreeze from the reservoir and forcibly pressing it into the pressure tank 52 to complete pressurization. After pressurization, the operator holds the operating nozzle 54 connected via a flexible hose, aims it at the external ice-accumulated area, and manually opens the switch valve 57. The pressure difference accumulated in the pressure tank 52 releases high-pressure antifreeze for targeted flushing and ice melting. Simultaneously, the contact lever 42 can be operated while pressurizing, similar to a foot switch.

[0048] Specifically, during normal use of the limit device (non-de-icing state), the antifreeze reservoir 51 in the transmission compartment 11 is physically disconnected from the lower chamber 32, and the inlet and outlet of the lower chamber 32 are tightly sealed with plugs. At this time, there is no liquid remaining inside the sealing cylinder liner 3, completely eliminating the potential risk of pipeline freezing and cracking due to water retention; the operating nozzle 54 and flexible hose are also properly stored inside the transmission compartment 11, avoiding physical collisions caused by external floating ice or hoisting machinery.

[0049] When the external contact lever 42 and lifting equipment are severely iced and de-icing is required, the operator shall perform the following assembly and operation procedures: Step 1 (Pipeline Assembly): The operator opens the transmission compartment 11 and removes the plug or cap on the lower chamber 32. Using a quick-connect fitting, connect the pipe with the inlet check valve 53a between the antifreeze reservoir 51 and the inlet of the lower chamber 32, and simultaneously connect the pipe with the outlet check valve 53b between the outlet of the lower chamber 32 and the pressure tank 52.

[0050] Step Two (Pump-Free Accumulation): Without relying on any external electric pump, the operator manually pushes and pulls the contact lever 42 up and down continuously (or controls an external lifting mechanism to slightly jog the lever). The swing of the contact lever 42 is converted into the linear reciprocating motion of the lifting rod 43 within the sealed cylinder liner 3. When the piston ring 431 moves upward, the volume of the lower chamber 32 expands, creating a negative pressure that draws antifreeze from the antifreeze reservoir 51 through the input check valve 53a. When the piston ring 431 moves downward, the volume of the lower chamber 32 compresses, generating high pressure that squeezes the antifreeze and forces it into the pressure tank 52 through the output check valve 53b. Repeating this process several times accumulates high-pressure antifreeze inside the pressure tank 52.

[0051] Step 3 (Spraying to Melt Ice): After pressurization is complete, the operator removes the operating nozzle 54 from the transmission compartment 11, stretches the flexible hose to lead it to the external space, and precisely aligns the nozzle nozzle with the contact lever 42 and mechanical shaft, as well as other areas prone to icing. The operator manually opens the switch valve 57, and the fluid pressure difference released from the pressure tank 52 instantly drives the high-pressure antifreeze to spray out, performing high-pressure flushing and chemical melting of the ice layer.

[0052] Step 4 (Draining and Resetting): After de-icing is complete, the operator closes the switch valve 57, disconnects all quick-connect fittings and separates the pipes, drains the small amount of residual liquid in the lower chamber 32, replaces the plug, and retracts the operating nozzle 54 into the transmission compartment 11 to return to the non-de-icing state.

[0053] In summary, in this embodiment, when the limiting device needs to be de-iced and cleaned, the lower chamber 32 within the sealed cylinder liner 3 can be used as a pumping chamber. An antifreeze cleaning flow path is established through the constraints of the pipeline and the one-way valve. By operating the contact lever 42, the lifting lever 43 moves up and down reciprocally, thereby driving the piston ring 431 to move. The upward movement of the piston ring 431 increases the volume of the lower chamber 32, generating negative pressure. Antifreeze is drawn in from the storage tank through the input one-way valve. The downward movement of the piston ring 431 compresses the volume of the lower chamber 32, thus preventing the antifreeze from being drawn in. The coolant is pressurized into the pressure tank 52 via the output check valve for pressure storage and energy accumulation. During de-icing, the operating nozzle 54 is removed and aimed at the part requiring de-icing, such as the exposed section of the contact swing arm or the exposed section of the lifting rod. The switch valve 57 is opened, and the contact swing arm is simultaneously operated to swing up and down. The high-pressure fluid accumulated in the pressure tank 52 is sprayed through the pressure nozzles 541 on both sides to flush away the ice layer. After one operation is completed, the operating nozzle 54 can be stored in the transmission compartment 11, the switch valve 57 is closed, and the corresponding pipes and check valves are disconnected. In this way, self-driven pressure storage de-icing without an external electric pump is achieved. Only antifreeze needs to be replenished periodically, greatly improving the convenience of de-icing maintenance.

[0054] In this embodiment, the sealing cylinder liner 3 includes a main body 30 and a sealing nut 33 threadedly connected to the bottom end of the main body 30. The main body 30 includes an integrally formed inner section 301 and a sleeve section 302. The outer wall of the inner section 301 has external threads and is threadedly and sealed to the through hole at the bottom of the sealing chamber 12. The upper end face of the sleeve section 302 abuts against the outer surface of the bottom of the sealing chamber 12. The lower end of the sleeve section 302 is connected to the sealing nut 33. The sealing nut 33 has a movable hole in the middle for the lifting rod 43 to pass through. An O-ring 7 is provided between the inner wall of the movable hole and the outer wall of the lifting rod 43 to achieve dynamic sealing between the lifting rod 43 and the movable hole.

[0055] Here, the sealing cylinder liner 3 adopts a top-down combined connection structure. The upper inner section 301 ensures that it is sealed and fixed to the bottom of the sealing chamber 12. In one embodiment, the inner section 301 is connected to the through hole by a thread. When performing subsequent maintenance of the sealing components, the maintenance personnel can unscrew the outer sealing nut 33 from the lower non-sealed transmission chamber 11 to release the O-ring 7. After pulling out the old part along the rod body to replace the new part, the radial sealing pressure can be restored by tightening it again.

[0056] Furthermore, an O-ring is provided between the upper end face of the sleeve section 302 and the sealing chamber 12, surrounding the through hole, to prevent external moisture from entering the sealing chamber 12 through the gap between the through hole and the inner section 301. An O-ring is provided around the lifting rod 43 on the inner wall of the inner section 301. In this way, a double-acting sealing fit is formed between the lifting rod 43 and the sealing cylinder 3 along the length direction of the sealing cylinder liner 3 or along the length direction of the lifting rod 43, further improving the sealing and waterproofing effect. An O-ring is provided between the sealing nut 33 and the lower end face of the sleeve section 302, surrounding the inner cavity of the sealing cylinder liner 3, to prevent external moisture from entering the sealing chamber 12 through the gap between the sealing nut 33 and the lower end face of the sleeve section 302.

[0057] To improve thermal insulation performance, the sleeve section 302 includes an inner sleeve and an outer sleeve arranged concentrically, and an annular first heating blanket 61 sandwiched between the outer wall of the inner sleeve and the inner wall of the outer sleeve. The first heating blanket 61 is used to conduct heat to heat the inner sleeve and the lifting rod 43 passing through it. A second heating blanket 62 is laid on the inner side wall surface of the sealed chamber 12 for heating the inner cavity of the sealed chamber 12. A temperature control power supply 63 is provided on the outer side wall of the sealed chamber 12. The temperature control power supply 63 is electrically connected to the second heating blanket 62 and the first heating blanket 61.

[0058] Here, the inner sleeve has a much higher thermal conductivity than the outer sleeve. Utilizing the thermal conductivity and insulation properties of the concentric metal tubes, the outer sleeve blocks the convective heat loss from the electric heating to the surrounding air, forcing the Joule heat generated by the first heating blanket 61 to be transferred radially along the inner sleeve, forming targeted heating for the movement gap of the lifting rod 43. The second heating blanket 62, on the other hand, maintains the cabin temperature through radiant heat. In this way, the freezing and jamming of the sliding dynamic seal gap due to condensation can be suppressed with extremely low power consumption, while ensuring the triggering reliability of the internal limit switch 2 in extremely cold environments.

[0059] In this embodiment, a mounting opening is provided on one side surface of the sealed chamber 12 for the limit switch 2 to be inserted and installed. The edge of the mounting opening is sealed with a cover plate 111 for closing the mounting opening by fasteners. A stuffing box 15 communicating with the inner cavity of the sealed chamber 12 is provided on the top of the housing 1. The mounting opening on the side provides an installation channel to facilitate the installation of the limit switch 2. The external cable introduced through the chamber is cut into the top of the housing from a high position, and the elastic sealing ring in the stuffing box 15 is screwed and tightened to seal the cable sheath.

[0060] In this embodiment, a connecting plate 13 is fixed on the outer wall of the box 1 near the ship carrier. The surface of the connecting plate 13 has multiple connecting holes, and fixing bolts 14 for fastening the box 1 to the ship deck are inserted into the multiple connecting holes.

[0061] In summary, the above embodiments not only significantly improve the watertight protection level of the limiting device in terms of structure, but also construct a redundant transmission structure to effectively prevent the lifting rod 43 from freezing and getting stuck. Furthermore, an ice-removing operation mechanism that does not require an external electric pump is introduced, which greatly reduces the operating cost and difficulty of ice removal and cleaning.

[0062] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A watertight limiting device suitable for polar ice environments, characterized in that, include: The housing (1) has its inner cavity vertically separated into a transmission compartment (11) located at the lower level and a sealed compartment (12) located at the upper level. The sealed compartment (12) is a closed independent cavity with a through hole at its bottom. Limit switch (2) is installed inside the sealed chamber (12), and the limit switch (2) has a trigger swing arm (22). A sealing cylinder liner (3) has one end threadedly connected to the through hole and the other end extending vertically toward the transmission compartment (11); The linkage mechanism (4) includes a contact swing rod (42) and a lifting rod (43). The contact swing rod (42) is installed in the transmission chamber (11) in a manner that allows it to swing up and down around a set fulcrum. The contact swing rod (42) has a first rod portion and a second rod portion separated on both sides of the set fulcrum. One end of the second rod portion extends out of the transmission chamber (11) to allow external objects to collide and trigger the limit switch. The lifting rod (43) is slidably inserted into the sealing cylinder sleeve (3) and the two are dynamically sealed together. Its upper end extends into the sealing chamber (12) and is connected to the trigger swing arm (22). Its lower end extends into the transmission chamber (11) and is hinged to the first rod portion of the contact swing rod (42). The downward swing of the contact swing rod (42) drives the lifting rod (43) to slide upward in the sealing cylinder sleeve (3), driving the trigger swing arm (22) to rotate and trigger the limit switch (2).

2. The watertight limiting device suitable for polar ice environments according to claim 1, characterized in that, The trigger arm (22) is configured to swing about a set axis and has two joints (221) that are symmetrical about the set axis. The sealing cylinder liner (3) is provided in two sets. The linkage mechanism (4) includes two lifting rods (43) that can slide up and down through the two sealing cylinder liners (3). The lower end of one lifting rod (43) is hinged to the first rod part of the contact rocker arm (42), and the lower end of the other lifting rod (43) is hinged to the second rod part. The upper ends of the two lifting rods (43) are respectively hinged to the two joints (221). The two lifting rods (43), the trigger rocker arm (22), and the contact rocker arm (42) together constitute a parallelogram mechanism.

3. The watertight limiting device suitable for polar ice environments according to claim 2, characterized in that, Each of the lifting rods (43) has an annular piston ring (431) on the rod body inside the corresponding sealing cylinder sleeve (3). The outer circumferential surface of the piston ring (431) slides and seals with the inner wall of the sealing cylinder sleeve (3), and divides the hollow inner cavity of the sealing cylinder sleeve (3) into an upper chamber (31) located above it and a lower chamber (32) located below it. The upper chamber (31) is provided with a spring (34) sleeved on the outside of the lifting rod (43) for resetting the lifting rod (43). The two ends of the spring (34) abut against the top inner wall of the sealing cylinder sleeve (3) and the top surface of the piston ring (431).

4. The watertight limiting device suitable for polar ice environments according to claim 3, characterized in that, It also includes an antifreeze tank (51), a pressure tank (52) and an operating nozzle (54), wherein the antifreeze tank (51) and the pressure tank (52) are located in the transmission compartment (11); Both sets of sealing cylinder liners (3) have an inlet and an outlet in the lower chamber (32). In the non-de-icing state, the inlet and outlet of the lower chamber (32) are closed. In the de-icing state, the inlet of the lower chamber (32) is connected to the antifreeze reservoir (51) via a pipe, and the pipe is provided with an inlet check valve (53a) for limiting the antifreeze to flow unidirectionally from the antifreeze reservoir (51) to the lower chamber (32); the outlet of the lower chamber (32) is connected to the pressure tank (52) via a pipe, and the pipe is provided with an outlet check valve (53b) for limiting the antifreeze to flow unidirectionally from the lower chamber (32) to the pressure tank (52). The outlet of the pressure tank (52) is connected to the operating nozzle (54) via a flexible hose, and a switch valve (57) is provided between them; in the non-de-icing state, the operating nozzle (54) is stored in the transmission compartment (11).

5. The watertight limiting device suitable for polar ice environments according to any one of claims 1 to 4, characterized in that, The sealing cylinder liner (3) includes a main body (30) and a sealing nut (33) connected to the bottom end of the main body (30) by threads. The main body (30) includes an integrally formed inner section (301) and a sleeve section (302). The outer wall of the inner section (301) has external threads and is threadedly connected to the through hole. The upper end face of the sleeve section (302) abuts against the bottom outer surface of the sealing chamber (12). The lower end of the sleeve section (302) is connected to the sealing nut (33). The sealing nut (33) has a movable hole in the middle for the lifting rod (43) to pass through. An O-ring (7) is provided between the inner wall of the movable hole and the outer wall of the lifting rod (43).

6. The watertight limiting device suitable for polar ice environments according to claim 5, characterized in that, The upper end face of the sleeve section (302) and the sealing chamber (12) are provided with an O-ring seal around the through hole. The inner wall of the inner section (301) is provided with an O-ring seal around the lifting rod (43). The sealing nut (33) and the lower end face of the sleeve section (302) are provided with an O-ring seal around the inner cavity of the sealing cylinder liner (3).

7. The watertight limiting device suitable for polar ice environments according to claim 6, characterized in that, The sleeve section (302) includes an inner sleeve and an outer sleeve arranged concentrically, and an annular first heating blanket (61) sandwiched between the outer wall of the inner sleeve and the inner wall of the outer sleeve. The first heating blanket (61) is used to conduct heat to heat the inner sleeve and the lifting rod (43) inserted therein. The inner wall surface of the sealed chamber (12) is covered with a second heating blanket (62) for heating the inner cavity of the sealed chamber (12). A temperature control power supply (63) is provided on the outer wall of the sealed chamber (12). The temperature control power supply (63) is electrically connected to the second heating blanket (62) and the first heating blanket (61).

8. The watertight limiting device suitable for polar ice environments according to claim 1, characterized in that, The linkage mechanism (4) also includes a vertical support rod (41), which is located at the bottom of the transmission compartment (11). The contact swing rod (42) can swing up and down and is supported on the top of the support rod (41). A roller (421) is provided at the end of the contact swing rod (42) that extends out of the transmission compartment (11).

9. The watertight limiting device suitable for polar ice environments according to claim 1, characterized in that, The sealing chamber (12) has an installation port on one side surface for the limit switch (2) to be inserted and installed. The edge of the installation port is sealed with a cover plate (111) for closing the installation port by fasteners. The top of the box (1) is provided with a stuffing box (15) that communicates with the inner cavity of the sealing chamber (12).

10. The watertight limiting device suitable for polar ice environments according to claim 1, characterized in that, A connecting plate (13) is fixed on the outer wall of the box (1) near the ship carrier. The surface of the connecting plate (13) has multiple connecting holes, and fixing bolts (14) for fastening the box (1) to the ship deck are inserted in the multiple connecting holes.

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